Matthew Fenty¹, Roshan Shah², Yinan Kuang³, Jeff Stambough², John Kelly⁴, Ravinder Reddy¹, and Fotios Tjoumakaris^5
1Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, United States, ²McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States, ³School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States, ⁴Sports Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, United States, ⁵Sports Medicine, Rothman Institute, Egg Harbor Township, NJ, United States

Ten subjects who presented clinically with Kellgren-Lawrence grade 1 or 2 osteoarthritis were imaged using T₁ MRI following routine treatment using Hylan G-F 20 viscosupplementation. Quantitative assessments of cartilage health was analyzed prior to VS, 6 weeks post-, and 3 months post-surgery to examine effects of VS within the joint.

Ligong Wang¹, Gregory Chang¹, Jenny T. Bencardino¹, James S. Babb¹, Andrew Rokito², Laith Jazrawi², Orrin Sherman², and Ravinder R. Regatte^1
1Radiology, NYU Langone Medical Center, New York, New York, United States, ²Orthopaedic Surgery, NYU Langone Medical Center, New York, New York, United States

The goal of this study was to assess T1rho values of femorotibial cartilage in acute anterior cruciate ligament (ACL) injured patients compared to healthy controls and osteoarthritis (OA) patients at 3T. 53 subjects (16 healthy controls, 17 acute ACL injured patients, and 20 OA patients) were scanned. LFa in ACL injured patients had significantly higher T1rho values (P < 0.05) than whole femorotibial cartilage and all cartilage subregions except LFa in healthy controls. These findings imply that cartilage T1rho mapping may be sensitive in staging femorotibial cartilage disorder among acute ACL injured patients, healthy controls, and OA patients.

Nade Sritanyaratana¹, Alexey Samsonov², Habib Abdulmohsen Al Saleh³, Kevin M Johnson³, Walter F Block⁴, and Richard Kijowski^2
1Biomedical Engineering, UW-Madison, Madison, Wisconsin, United States, ²Radiology, UW-Madison, Madison, WI, United States, ³Medical Physics, UW-Madison, Madison, WI, United States, ⁴Biomedical Engineering, UW-Madison, Madison, WI, United States

Quantitative magnetization transfer (qMT) offers possible new biomarkers obtained through the magnetization transfer effect. Previous studies have observed qMT parameters of cadaveric or animal specimen cartilage, fixing T2b to calculate the fit. This study observed the bound pool fraction (f), exchange rate constant (k), and bound pool T2 (T2b) of patellar cartilage in human volunteers within 30 minutes. Significant differences (p=0.0001/0.002) were found in f/T2b between the deep and superficial layers of the cartilage. Additionally, it was found that the T2b in older active volunteers was significantly higher (p=0.01) than the T2b found in the younger sedentary volunteers.

Bragi Sveinsson^1,2, Ernesto Staroswiecki^1,2, Kristin Granlund^1,2, Garry E. Gold¹, and Brian A. Hargreaves^1
1Radiology, Stanford University, Stanford, California, United States, ²Electrical Engineering, Stanford University, Stanford, California, United States

Double Echo in Steady State is a 3D steady state method that has been demonstrated to provide accurate measurements of ADC in articular cartilage in short scan times with high SNR and low distortion. One approach estimates T1 and T2 as well as the ADC. Another approach eliminates dependency on T1 and T2 to estimate ADC more quickly. Both approaches suffer from sensitivity to B1 deviations when estimating ADC. We demonstrate a method to reduce errors caused B1 deviations. The method is tested in phantoms and in vivo with positive results.

Mai L.H. Nguyen¹, Weitian Chen², and Garry E. Gold^3
1Stanford University, Stanford, CA, United States, ²Global MR Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, ³Radiology, Bioengineering, and Orthopedics, Stanford University, Stanford, CA, United States

This work assesses the ability of CubeQuant, a new MR method based on 3D FSE, for 3D T1rho and T2 quantification of articular cartilage. A total of 9 patients were imaged with CubeQuant and a comparison of CubeQuant with MAPSS was performed on phantoms. There was good agreement between T2 relaxation time measurements with CubeQuant and MAPSS. In addition, correlation was seen between T1rho and T2 measurements in most regions of the cartilage. T1rho relaxation times were longer than T2 in all cartilage regions. CubeQuant can potentially provide traditional anatomic information in addition to biochemical data regarding cartilage.

Toshiyuki Shiomi¹, Pavol Szomolanyi^1,2, Vladimir Juras^1,2, Stefan Zbyn¹, Takashi Nishii³, and Siegfried Trattnig^1
1MR Centre of Excellence, Department of Radiology, Medical University Vienna/Vienna General Hospital, Vienna, Austria, ²Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, ³Department of Orthopaedics, Osaka University Medical School, Osaka, Japan

The purpose of this study was to characterize the time-dependence of cartilage stiffness under static loading using T2 mapping of the femoral cartilage of the knee joint in vivo in healthy volunteers. During the first loading period (10 minutes), the largest decrease of -8.2% of the T2 value was observed. T2 values exhibited a nonlinear dynamic change over time and reached stable values after 10 minutes of loading/unloading. Loading of the knee during MRI can provide biomechanical characteristics of the human knee cartilage. Statistically significant changes in cartilage T2 during the loading and unloading phases provide insight into cartilage properties.

Peter Huy Pham¹, Scott Somers², Nirmalya Ghosh³, and Hiroshi Yoshioka^1
1Radiologic Sciences, University of California, Irvine, Orange, CA, United States, ²Radiology, Loma Linda University Medical Center, Loma Linda, CA, United States, ³Non-invasive Imaging Lab, Loma Linda Univeristy Medical Center, Loma Linda, CA, United States

We attempt to identify early knee cartilage damage and distinguish it from magic angle effect using a novel orientation and thickness dependent T2 mapping approach in Osteoarthritis Initiative patients. Custom software measured T2 relaxation time in cartilage divided by orientation relative to B0 and thickness. Approximately 85% of signal heterogeneity lesions and 100% of focal lesions <1cm were detected. Lesions at 55 degrees were distinguished from magic angle effect. Some lesions were only detectable on separate analysis of deep and superficial layers. Orientation and thickness dependent T2 mapping is sensitive for early cartilage degeneration and can separate it from magic angle effect.

Scott M Somers¹, Peter Pham², Nirmalya Ghosh¹, and Hiroshi Yoshioka^2
1Radiology, Loma Linda University Medical Center, Loma Linda, California, United States, ²Radiology, University of California Irvine, Orange, California, United States

Because T2 relaxation time increases in cartilage before morphologic changes are visible, understanding the normal profile in cartilage is essential to identifying early disease. Using custom software, we measured T2 relaxation time in 5 degree segments for deep, superficial, and full thickness cartilage of the medial femoral condyle in 105 patients using a novel T2 mapping approach. The results of this study emphasize the importance of evaluating deep and superficial cartilage separately, as well as considering orientation of the cartilage to the main magnetic field when T2 mapping is used for diagnosis of cartilage disease.

Mikko Johannes Nissi¹, Jinjin Zhang¹, Djaudat Idiyatullin¹, Curtis Corum¹, Cathy Carlson², Ferenc Toth², Miika Tapio Nieminen^3,4, and Jutta Ellermann^1
1CMRR - Dept. of Radiology, University of Minnesota, Minneapolis, MN, United States, ²Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN, United States, ³Department of Medical Technology, University of Oulu, Oulu, Finland, ⁴Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland

The involvement of the osteochondral interface in osteoarthritis is known, but perhaps less appreciated than warranted. Recent developments in ultrashort/zero-echo time imaging methods have enabled the MRI investigation of calcified and subchondral structures. In uTE studies, the bright line at the cartilage-bone interface has been associated with calcified layer of cartilage and deep layers of cartilage. In the present study, SWIFT was utilized to further study the origin of this feature. The results confirmed the earlier findings but also pointed to a possible contribution of signal pileup due to susceptibility differences between cartilage and bone or calcified cartilage.

Yongxian Qian¹, Ashley A. Williams², Constance R. Chu², Cynthia A. Britton¹, and Fernando E. Boada^1,3
1Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ²Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States,³Bioengineering, University of Pittsburgh

This work illustrates the potential of high resolution (0.14mm) ultrashort echo time (UTE) imaging for non-invasively visualizing micro cartilage defects and damages in human knee. Five patients with clinically-graded cartilage defects (arthroscopic grading) were scanned on a clinical MRI scanner at 3T, using a customer-developed fast 3D UTE pulse sequence, acquisition-weighted stack of spirals (AWSOS). The findings on HR-UTE images were verified by the clinical arthroscopic grading.

Eveliina Lammentausta¹, Simo Saarakkala^2,3, Risto Ojala², and Miika T Nieminen^2,3
1Department of Clinical Imaging, Oulu University Hospital, Oulu, OYS, Finland, ²Oulu University Hospital, ³University of Oulu, Oulu, Finland

T1 relaxation time was measured 90 minutes after intravenous and intra-articular Gd-DTPA administration to investigate the transport routes of gadolinium into articular cartilage. Significan differences were observed in superficial and full thickness cartilage, but not in deep cartilage. The present results suggest that most of the Gd-DTPA transports into articular cartilage from the synovial fluid regardless of the injection method.

Annie Horng¹, José Raya², Monika Zscharn¹, Ulrike Hoehne-Hueckstaedt³, Ulrich Glitsch³, Rolf Ellegast³, Kurt Georg Hering⁴, Maximilian F Reiser¹, and Christian Glaser^1
1Department of Clinical Radiology, University Hospitals LMU Munich Campus Grosshadern, Munich, Bavaria, Germany, ²Center of Biomedical Imaging, New York University Medical Hospital, New York, New York, United States, ³Fachbereich 4, Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung, St. Augustin, Germany,⁴Department of Radiology and Nuclear Medicine, Knappschaftskrankenhaus, Dortmund, Germany

Cartilage strain is considered a potential cause for degeneration and osteoarthritis. 3D-HR-MRI was utilized and proved able to evaluate the dimension and distribution of cartilage deformation in the knee joint after different standardized flexion exercises. The deformation pattern was similar for the excercises, possibly a consequence of mutual knee flexion over 90°. Specific patterns were visible for squatting and knee bends possibly due to higher flexion grade in the former and dynamic movement character in the latter. The data may support the understanding of individual knee kinematics and contribute to improvement and validation of biomechanical models for the knee.

Ying Xia^1,2, Jurgen Fripp², Shekhar Chandra², Olivier Salvado², Raphael Schwarz³, Lars Lauer³, Craig Engstrom⁴, and Stuart Crozier^1
1School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia, ²The Australia e-Health Research Centre, CSIRO ICT Centre, Brisbane, Australia, ³Siemens Healthcare, Erlangen, Germany, ⁴School of Human Movement Studies, University of Queensland, Brisbane, Australia

Osteoarthritis (OA) is a common disease of the hip joint characterized by changes in structure and degeneration of cartilage tissue. Magnetic Resonance (MR) imaging has been shown to be an ideal modality for OA assessment, providing direct and non-invasive visualization of joint structure. Morphological measurements (volume, thickness and surface area) of the cartilage tissue have been shown to be important in characterizing and monitoring OA progression, which allows the prediction of its subsequent changes and in-time therapeutic treatment before permanent damage has been developed. In this paper, we present validation of our fully automated scheme for the bone segmentation and qualitative bone-cartilage interface (BCI) extraction and initial cartilage segmentation from MR images of the hip joint.

R Mark Wellard¹, Alf Pawlik², Sabrina Barheine², and Konstantin I Momot^3
1QUT, Brisbane, Qld, Australia, ²QUT, ³QUT, Australia

The early changes associated with osteoarthritis of articular cartilage are not well understood. Our objective was to better understand the metabolite distribution in cartilage. We studied the changes in intact bovine patellar cartilage using solid-state ¹H and ¹³C MAS NMR following incubation of the cartilage in D₂O to remove free water. The influence of freezing and thawing on the eluted metabolites was determined using ¹³C NMR. Examination of the ¹H MAS NMR spinning side-bands suggests the presence of multiple bound states of water. Metabolite elution following frozen storage of cartilage shows an increased loss of proteoglycans, relative to fresh tissue.

Gunthard Lykowsky¹, Kathrin Hemberger¹, Peter M. Jakob^1,2, and Daniel Haddad^1
1MRB Research Center, Würzburg, Germany, ²Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany

Sodium is known to be a sensitive MR imaging biomarker for early diagnosis of knee articular cartilage osteoarthritis (OA). The goat animal model closely matches the human knee anatomy and can be used to mimic the progressive nature of OA and monitor the loss of proteoglycans. We have developed a TORO (transmit-only, receive only) coil setup which allows, in combination with a 3D UTE sequence, improved sodium imaging of the goat knee at 1.5T. High quality sodium images of the goat knee are shown.

Anne-Laure Perrier¹, Emmanuel Chereul², Denis Grenier¹, Fabrice Taborik³, Mariam Abdallah¹, Thomas Chuzel², Stéphane Martin², Luc Magnier², Jean-Christophe Goebel¹, Xavier Pesesse⁴, Sandra Pietri⁵, Hugues Contamin³, and Olivier Beuf^1
1Université de Lyon; CNRS UMR 5220; Inserm U1044, INSA-Lyon; Université Lyon 1, Villeurbanne, France, ²VOXCAN, Marcy l'Etoile, France, ³Cynbiose, Marcy l’Etoile, France,⁴Bone Therapeuthics, Grosselies, Belgium, ⁵Laboratoire de Rhumatologie, Hôpital Erasme, ULB, Bruxelles, Belgium

Small animal model of osteoarthritis (OA) models do not always mimic with adequacy human disease. Moreover, despite superior tissue contrast and sensitivity to cartilage tissue structure, spatial resolution is limited compared to CT scanner and an accurate determination of cartilage morphology is challenging due to the small size of rodent joints. In the contrary, OA that closely resembles to the human condition occurs naturally in primate. In this context, the aim of this work was (i) to develop a dedicated protocol for knee joint examination of cynomolgus primates at 1.5T and with µ-CT arthroscanner (µCTA); (ii) to compare morphological parameters assessed based on MRI and µCTA acquisitions on a group of 10 old primates with spontaneous OA.

Ziying Yin¹, Thomas M. Schmid², Lawrence Madsen², Mrignayani Kotecha¹, and Richard L. Magin^1
1Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, ²Department of Biochemistry, Rush University, Chicago, IL, United States

Noninvasive assessment of tissue-engineered cartilage is essential to optimize the production of neocartilage with appropriate biochemical properties for implantation; MRI is ideally suited to this. One approach to regenerating cartilage involves culturing chondrocytes in scaffold-free pellet culture. In this study, we used MRI to evaluate the scaffold-free chondrocyte pellets over a 4-week period, and observed the distinct changes in histograms of T2, T1, T1¦Ñ and apparent diffusion coefficient, which were correlated with the results of biochemical determination of proteoglycan and collagen from the pellets. The results suggest that MRI could be used to assess specific biochemical properties of engineered cartilage.

Christina Hopfgarten¹, Stefan Kirsch¹, Gregor Reisig², Michael Kreinest², and Lothar R. Schad^1
1Computer Assisted Clinical Medicine, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany, ²Department for Experimental Orthopaedics and Trauma Surgery, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany

Interpretation of MR images of menisci is hampered by the magic angle (MA) effect. The MA effect manifests itself as a strong spatial inhomogeneity in the MR images caused by orientational dependence of the transverse relaxation time T2. Here we demonstrate experimentally that magnetization transfer ratio (MTR) maps show no visible sensitivity to the MA effect. Therefore, MTR maps have the potential to identify tissue degeneration while not being affected by the MA effect. This phenomenon could be useful in in vivo studies of pathological tissue degeneration of human menisci.

Emily J McWalter¹, Bragi Sveinsson¹, Ernesto Staroswiecki¹, Marcus T Alley¹, Brian A Hargreaves¹, and Garry E Gold^1
1Radiology, Stanford University, Stanford, CA, United States

We demonstrated the feasibility of measuring T2 and T2* relaxation of the meniscus in vivo using 3D quantitative DESS (qDESS) in 5 healthy individuals. The results of this study are consistent with previous meniscal T2 and T2* measurements in healthy volunteers with mean values of 10.5 ± 1.6 ms and 7.2 ± 0.6 ms, respectively; however, we were able to acquire data of similar resolution in shorter scan times and create maps in three planes. 3D qDESS has the potential to be used for detecting early meniscal degeneration.

Ping-Huei Tsai^1,2, Shih-Wei Chiang³, Yue-Cune Chang⁴, Chao-Ying Wang³, Ming-Chung Chou⁵, Hsiao-Wen Chung⁶, and Guo-Shu Huang^3
1Imaging Research Center, Taipei Medical University, Taipei, Taiwan, ²Department of Radiology, WanFang Hospital, Taipei, Taiwan, ³Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ⁴Department of Mathematics, Tamkang University, Taipei, Taiwan, ⁵Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ⁶Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan

Human meniscus plays an important role on maintenance of the knee mechanical functions and is strongly associated with early detection of osteoarthritis (OA) which is frequently characterized with degeneration of cartilage and mostly related to aging. Zonal difference of the meniscus was demonstrated by previous report using quantitative T2 measurements. In addition, aging and gender may be other factors that could affect the diagnostic value of quantitative T2 measurements in the menisci. The purpose of this study is to investigate the relationship between regional T2 variations and aging effect in asymptomatic men and women.

Sung M. Moon^1,2, Jon H. Yoder², Ed J. Vresilovic³, Dawn M. Elliott², and Alexander C. Wright^1
1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States, ³3Department of Orthopaedics and Rehabilatation, Penn State University, Hershey, PA, United States

Intervertebral disc degeneration is considered one of the key causes of back pain while very little is known about the MR characteristics of the CEP (cartilaginous end-plate) because it is very thin (~600µm) and difficult to image and recognize on routine MR exams. Visualizing CEP and/or measuring water content of the CEP are important for the evaluation of disc degeneration. However, measuring CEP thickness challenging in vivo due to voxel size. In this study, high-resolution ex vivo CEP images and low-res in vivo images were acquired and evaluated for different voxel sizes, and estimated error was reported using automated program.

Trevor Andrews^1,2, Richard Watts², Scott Hipko², Jay Gonyea², and Christopher Filippi^2,3
1Philips Healthcare, Cleveland, OH, United States, ²Radiology, University of Vermont College of Medicine, Burlington, VT, United States, ³Radiology, Fletcher Allen Health Care, Burlington, VT, United States

In this work the performance of 3D T1rho mapping of spine discs at 3T is investigated both with and without RF shimming.

Cheng Li¹, Jeremy Magland¹, and Felix Wehrli^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

Ultra-short echo time (UTE) imaging is a technique for directly imaging tissues with sub-millisecond T2 values. However, 2D UTE imaging is inherently time-inefficient because of half-pulse excitation and radial center-out sampling. In this work we describe 3D Compressed Sensing UTE (COMPUTE) imaging with a hybrid-radial encoding strategy to improve efficiency. Phantom and in vivo results demonstrate the feasibility of COMPUTE technique with an acceleration factor of 10. In work in progress, long-T2 suppression modules are being incorporated into COMPUTE, allowing spatial sparsity of the soft-tissue suppressed images to be exploited to achieve even higher acceleration factors.

David K.W. Yeung¹, James F Griffith², Heather T Ma^3,4, and Alvin F.W. Li^2
1Imaging and Interventional Radiology, Prince of Wales Hospital, Shatin, HKSAR, Hong Kong, ²Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, HKSAR, Hong Kong, ³Department of Electronic and Information Engineering, Harbin Institute of Technology, China, ⁴Imaging and Interventional Radiology, The Chinese University of Hong Kong, HKSAR, Hong Kong

What causes osteoporosis is still incompletely understood. One hypothesis that has recently attracted a lot of attention is the vascular origin of the disease. In this study we attempted to use BOLD imaging to study bone marrow perfusion. We showed that observable BOLD signal changes may be measured from the bone marrow of human volunteers.

Bailiang CHEN^1,2, Tryphon Lambrou³, Gabriela HOSSU^1,4, Pedro Teixeira⁵, Pierre-André VUISSOZ^1,2, and Jacques FELBLINGER^1,2
1IADI, INSERM U947, Nancy Université, Nancy, Lorraine, France, ²Pôle Imagerie, CHU de Nancy, Nancy, France, ³Institute of Nuclear Medicine, University College London, London, United Kingdom, ⁴CIC-IT 801, CHU de Nancy, Nancy, France, ⁵Service d’Imagerie Guilloz, CHU de Nancy, Nancy, France

Bone marrow is a dynamic organ with significant changes in its composition throughout life. Alterations in the conversion between red (hematopoietic) and yellow (adipose) marrow may be a sign for an alteration of the local microvascular environment caused by local or systemic diseases. The distribution pattern of red bone marrow, residual or reconverted, may assist the differentiation between normal and pathologic bone marrow. Such residual red marrow is sometimes difficult to be detected by conventional sequences. In this study, we presented an in-vivo diffusion based MR protocol to assess the red marrow in the tibia epiphysis.

Giulia Di Pietro^1,2, Vincenzo Vinicola³, Guglielmo Manenti⁴, Mauro Rebuzzi², Gisela Hagberg⁵, Salvatore Masala⁴, Giovanni Simonetti⁴, Marco Bozzali⁵, and Silvia Capuani^2,6
1IIT@Sapienza, Physics Department, Rome, Rome, Italy, ²“Sapienza” University of Rome, Physics Department, Rome, Rome, Italy, ³Rehabilitation Hospital IRCCS Santa Lucia Foundation, Rome, Italy, ⁴Department of Diagnostic Imaging and Interventional Radiology, University of “Tor Vergata”, Rome, Italy, ⁵Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy, ⁶CNR IPCF UOS Roma, Physics Department, Rome, Italy

Lipidic profile of bone marrow was investigated, using 1H-MRS at 3T, in the calcaneus and the femoral neck of postmenopausal healthy , osteopenic and osteoporotic women. Preliminary data obtained in femur, indicate that resonance L53 is a biomarker suitable for identifying healthy subjects, while resonance L09 is the best marker to identify osteoporotic subjects. Taken together, these measures might provide a sensitive and specific test for screening of populations at risk for osteoporosis. Additionally, in calcaneus, the simultaneous quantification of resonances L09,L43, L41 and L28+L23+L21 offers a chance to increase the diagnostic confidence of osteoporosis in low cost dedicated spectrometers.

Maite Aznarez-Sanado¹, Cheng Li¹, Jeremy F Magland¹, Chamith S Rajapakse¹, and Felix W Wehrli^1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Proton MR spectroscopy is a valuable technique for the assessment of bone marrow. The main purpose of this study was to evaluate the performance of a fast, multi-echo chemical-shift imaging method for in vivo quantification of vertebral marrow fat fraction. Five healthy subjects underwent the imaging paradigm twice with complete repositioning of the subject each time. In vivo marrow fat fraction measurements obtained at each vertebral level (L1-L5) were highly reproducible. The results suggest that this technique may reliably detect variations in the marrow fat fraction on the order of 4% in 95% of the cases.

Silvia Capuani¹, Guglielmo Manenti², Roberto Sorge³, Parfait Assako², Umberto Tarantino⁴, Salvatore Masala², and Giovanni Simonetti^2
1Physics Department, CNR IPCF Roma "Sapienza " University of Rome, Rome, Italy, Italy, ²Diagnostic and Interventional Radiology, Molecular Imaging and Radiotherapy, "Tor Vergata" University of Rome, Rome, Italy, ³Institute of Medical Informatics and Biometry, "Tor Vergata" University of Rome, Rome, Italy, ⁴Department of Orthopaedics and Traumatology, PTV Foundation, "Tor Vergata" University of Rome, Rome, Italy

We reported, for the first time, MD and FA results obtained from femoral neck of healthy (H), osteopenic (OPE) and osteoporotic (OPO) subjects, classified according to DXA criteria. Because MD and FA in cancellous bone depend on both the trabecular-bone rearrangement and the marrow fat-water ratio content (FF) a DTI protocol in combination with 1H-MRS was used. Our preliminary results, show that MD/FF and FA/FF differentiate among H, OPE and OPO subjects with a high sensitivity and specificity in identifying H subjects. DTI-1H-MRS assessment in femoral neck might represent a potential procedure to improve the diagnostic confidence of osteoporosis.

Maite Aznarez-Sanado¹, Chamith S Rajapakse¹, Ning Zhang¹, Jeremy F Magland¹, Michael J Wald¹, Alex C Wright¹, Yusuf A Bhagat¹, Wenli Sun¹, and Felix W Wehrli^1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Assessment of bone strength in the proximal femur, a frequent site of traumatic fracture, is of significant clinical interest. Micro finite-element analysis (FEA) is a valuable tool for estimating bone strength. To determine the viability of FEA on the basis of in vivo MR images obtained at the proximal femur, FEA based on ex vivo high-resolution micro-computed tomography, simulated low resolution MR and in vivo MR images were performed. Strain maps derived from the analyses qualitatively showed similar loading characteristics. The results indicate the feasibility of FEA based on in vivo MR images of the proximal femur.

Ning Zhang¹, Jeremy F Magland¹, Chamith S Rajapakse¹, Yusuf A Bhagat¹, and Felix W Wehrli^1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, PA, United States

High-resolution image-based non-linear micro-finite element (µFE) modeling can directly predict bone failure behavior thereby assessing osteoporotic fracture risk. In this work, a new program for non-linear μFE modeling was developed to estimate trabecular bone (TB) yield parameters based on a computationally efficient algorithm for linear µFE analysis in conjunction with establishment of a TB failure criterion. A reproducibility study on in-vivo μMR images was conducted to assess its performance. The ability to distinguish means between four healthy young subjects suggests that the yield parameters derived from the non-linear program have reproducibility adequate to evaluate treatment effects in interventional studies.

Ning Zhang¹, Jeremy Magland¹, Chamith Rajapakse¹, Yusuf Bhagat¹, and Felix Wehrli^1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

High-resolution MR or CT image-based micro-finite element modeling has shown promise for estimating bone mechanical behavior, assessing osteoporotic fracture risk and evaluating the response to drug intervention. Limitations in computing power so far have restricted μFE models to the linear regime yielding only bone elastic parameters. In contrast, nonlinear μFE models are able to predict bone’s failure strength but are computationally far more demanding. In this work we apply newly developed µFE software to explore the relationship between trabecular bone yield stress predicted by nonlinear μFE and axial stiffness computed from linear μFE models and present initial results on the basis of μMR and μCT images.

Wenli Sun¹, Chamith Rajapakse¹, and Felix W. Wehrli^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

Although micro-MRI-based biomechanics has been used to study mechanical alterations in trabecular bone due to disease or treatment, sensitivity of this approach under typical patient imaging conditions has not been well established. We investigated weather finite-element analysis performed on the basis of simulated ¡°in vivo¡± micro-MR images of the distal tibia is capable of detecting a reduction in axial stiffness resulting from a small amount of trabecular bone erosion and perforation. The data suggest that mechanical implications caused by subtle changes in trabecular bone are detectable via finite-element modeling under in-vivo micro-MR imaging conditions now achievable in patients.

Yusuf A Bhagat¹, Maite Aznarez-Sanato¹, Jeremy F Magland¹, Theresa M Scattergood², Peter J Snyder², and Felix W Wehrli^1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, PA, United States, ²Division of Endocrinology, Diabetes and Metabolism, University of Pennsylvania, Philadelphia, PA, United States

Recent advances in high-resolution structural imaging of trabecular and cortical bone and the use of these data as input into micro-finite-element (µFE) models have shown potential for assessing the effect of treatment in patients with osteoporosis. Here, we report baseline and 1 year follow-up data in an ongoing investigation of women with low bone density (N=15) receiving either zoledronic acid or teriparatide, conducted at 3T and 7T. The baseline data show moderate associations with pQCT bone density while µFE-derived axial stiffness is strongly correlated with bone volume fraction at the same site. Finally, repeat data in select subjects indicate large anabolic effects.

Cheng Li¹, Yusuf A Bhagat¹, and Felix W Wehrli^1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, PA, United States

Ultra-short echo-time (UTE) MRI enables detection of cortical bone water. Quantification of pore water would permit an indirect estimation of porosity, currently unachievable in vivo. In this study, we examined the role of the suppression ratio (SR, unsuppressed/soft-tissue suppressed UTE signal) as a surrogate measure for porosity in 18 healthy women (27-81 years old) who underwent scanning of the mid-diaphyseal tibia at 3T with three soft-tissue suppression UTE-MRI schemes. SR was found to increase with age and was inversely correlated with bone mineral density. SR may provide an in vivo surrogate measure of porosity.

Alan C Seifert¹, Alexander C Wright¹, Henry H Ong¹, Thomas J Connick¹, Stephen Pickup¹, Suzanne L Wehrli², and Felix W Wehrli^1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²NMR Core Facility, Children's Hospital of Philadelphia, Philadelphia, PA, United States

X-ray-based bone mineral density examinations measure apparent, rather than true, density. Solid-state 31P MRI has the potential to quantify true density, but due to uniquely unfavorable relaxation properties, SNR’s dependence on field strength is not certain. We therefore measured T1 and T2* of 31P in five lamb cortical bone samples by saturation-recovery and line width at five field strengths (3T-11.7T), and calculated predicted SNRs using the gradient-echo signal equation. With increasing B0, T1 increased from 26s to 97s, and T2* decreased from 189µs to 98µs. If k-space center is sampled <130µs after excitation, higher field strength should provide better SNR.

R. Adam Horch^1,2, Jeffry S Nyman^3,4, Daniel F Gochberg^2,5, Mary Kate Manhard^1,2, and Mark D Does^1,2
1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ²Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ³VA Tennessee Valley Healthcare System, ⁴Department of Orthopaedics & Rehabilitation, Vanderbilt University, Nashville, TN, United States, ⁵Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States

Modern ultrashort echo-time (uTE) MRI is a clinically feasible method for imaging human cortical bone. The conventional uTE signal from cortical bone contains non-discriminated contributions from both bound and pore water. Previous work has linked bound or pore water-discriminated measures to bone mechanical properties, so it is necessary to isolate bound from pore water for diagnostic utility. This work explores two modifications to uTE MRI, which incorporate T2-selective adiabatic full passage (AFP) RF pulses to selectively image bound or pore water. These AFP methods are performed with clinically-relevant scan parameters and provide quantitative images of bound or pore water.

Annie Papadaki¹, Jeff Hand², John Powell³, Donald McRobbie⁴, and Alister Hart^5
1Radiological Sciences Unit, Imperial College Healthcare NHS Trust, London, England, United Kingdom, ²Imaging Sciences, Imperial College, London, United Kingdom, ³Stroke and Dementia Research Centre, St Georges University of London, London, England, United Kingdom, ⁴Radiological Sciences Unit, Imperial College NHS Trust, London, England, United Kingdom, ⁵Department of Musculoskeletal Surgery, Imperial College, London, United Kingdom

Localised SAR around CoCr hip implants at 1.5T and 3T result in SAR10g exceeding the established limits. This is not necessarily worse at 3T and depends upon body shape and position within the RF transmit coil.

Catherine L Hayter¹, Matthew F Koff¹, Edwin P Su², Kevin M Koch³, Parina Shah¹, Stephanie L Gold¹, and Hollis G Potter^1
1Department of Radiology and Imaging - MRI, Hospital for Special Surgery, New York, New York, United States, ²Center for Hip Pain and Preservation, Hospital for Special Surgery, New York, New York, United States, ³Applied Science Laboratory, General Electric Healthcare, Waukesha, Wisconsin, United States

Metal-on-metal (MOM) hip resurfacing can be associated an adverse local tissue response (ALTR) which may manifest as synovitis or osteolysis. The purpose of this prospective, observational study was to review patterns of osteolysis and synovitis in symptomatic and asymptomatic individuals following MOM hip resurfacing. Synovitis was detected in a similar proportion of symptomatic and asymptomatic patients. Osteolysis was only detected in symptomatic individuals. The volume of synovitis was significantly higher in subjects with ALTR (p=0.01), as were levels of serum Cr (p=0.045) and Co (p=0.01). In the ALTR group there was a significantly higher proportion of females (p=0.048) and subjects with implants with abnormal acetabular component alignment (p=0.03). MRI is the most suitable non-invasive means by which to screen symptomatic and asymptomatic patients for the presence of synovitis. MRI can differentiate individuals with a normal pseudocapsule from those patients with synovitis, which, in combination with clinical findings and serum ion levels, will help to guide patient management. The finding of a high volume of synovitis on MRI should alert the clinician towards the need for close patient monitoring and possible revision surgery, particularly in the setting of elevated serum ion levels, female sex and abnormal component alignment.

Catherine L Hayter¹, Matthew F Koff¹, Stephanie L Gold¹, Giorgio Perino², Kevin M Koch³, and Hollis G Potter^1
1Hospital for Special Surgery, Department of Radiology and Imaging - MRI, New York, New York, United States, ²Hospital for Special Surgery, Department of Pathology and Laboratory Medicine, New York, New York, United States, ³Applied Science Laboratory, General Electric Healthcare, Waukesha, Wisconsin, United States

Metal on metal (MOM) prostheses may be complicated by aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL), which can manifest as synovitis or osteolysis. The purposes of this study were to review patterns of synovitis and osteolysis in subjects with pain following MOM hip resurfacing arthroplasty (RSA) and MOM total hip arthroplasty (THA) and correlate the MRI findings with results at revision surgery. Synovitis was present in 77% of RSA and 86% of THA hips. Mean synovial volume was higher in the THA group; however, this did not reach significance (p=0.18). There was no difference in the incidence of osteolysis (p=0.17), synovitis (p=0.51) or extracapsular disease (p=0.67) between the two groups. 20 subjects underwent revision surgery, of which 12 were diagnosed with ALVAL. Subjects with ALVAL had a significantly higher mean volume of synovitis (p=0.04) compared to those without ALVAL. Extracapsular disease and muscle edema were only detected in subjects with ALVAL. MRI is a useful assessment tool in patients with pain following MOM hip arthroplasty. MRI can detect synovitis, extracapsular disease and osteolysis, which may indicate ALVAL at revision surgery. Early results suggest that the most reliable MRI signs of ALVAL are extracapsular disease, high volumes of synovitis and intramuscular edema.

Jessica Winfield¹, and Donald McRobbie^1
1Imperial College Healthcare NHS Trust, London, United Kingdom

We present a method to use MRI to measure concentrations of metal ions in fluid-filled pseudotumours near metal-on-metal (MoM) hips. The method uses 3D gradient echo sequences which exhibit only moderate metal artefacts when a high receive bandwidth is employed. Measurements of T1 relaxation times can be used to place upper limits on concentrations of metal ions in fluid-filled lesions. The study forms part of the long-term follow-up of patients with painful and well-functioning MoM hips in order to investigate the clinical significance of pseudotumours and elevated levels of metal ions.

Qingwei Liu¹, Morgan B Giers², Alex McLaren³, Christopher S Estes³, Michael R Caplan⁴, Gregory H Turner¹, and Ryan Y McLemore^3
1Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, ²Harrington Department of BioMedical Engineering, Arizona State University, Tempe, AZ, United States, ³Orthopaedic Residency, Banner Good Samaritan Medical Center, Phoenix, AZ, United States, ⁴School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States

Periprosthetic infection is a devastating complication of joint replacement. Traditional local delivery experiments have been explored in vitro, but it is more important to study actual drug distribution in vivo. In this study, we used contrast enhanced MR imaging to track the delivery of small molecules through the complex delivery environment of bone, local tissues, and local blood flow. The elution of Gd marked drugs was observed after the surgery, which clearly showed continuous delivery of drugs in the tissue. The MRI T1 map technique was proved to be able to track the distribution of antibiotics in orthopaedic wounds.

Pia Baumann^1,2, Thomas Widek¹, Heiko Merkens¹, Julian Boldt³, Andreas Petrovic^1,4, Barbara Kirnbauer⁵, Norbert Jakse⁵, and Eva Scheurer^1,2
1Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria, ²Medical University, Graz, Austria, ³Department of Prosthodontics, Julius Maximilians University, Würzburg, Germany, ⁴University of Technology, Institute of Medical Engineering, Graz, Austria, ⁵University Clinic for Oral and Maxillofacial Medicine, Graz, Austria

Dental age estimation is important for forensic age estimation in living adolescents which to date is based on the evaluation of an orthopantomogram. However, the use of ionizing radiation without medical indication is not permitted in many countries. In this study, MRI was compared to the orthopantomogram regarding dental development. The developmental stages could well be differentiated in MRI. While mineralization in the MRI tended to be associated with stages higher than in the orthopantomogram, eruption showed an almost perfect correlation between both methods. These results show that MRI might replace the orthopantomogram for dental age estimation in the future.

Jakob Kreutner¹, Andreas J. Hopfgartner², Julian Boldt³, Kurt Rottner³, Daniel Haddad¹, Ernst J. Richter³, and Peter M. Jakob^1,2
1Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany, ²Experimental Physics 5, University of Würzburg, Würzburg, Germany, ³Prosthodontics, Dental School, University of Würzburg, Würzburg, Germany

Planing of dental implants requires precise knowledge about dimensions of the defect and bone strength at this position. This work shows that MRI is capable to clearly depict the nerve canal running in the mandbile as well as resolving the trabecular microstructure within a reasonable scan time in vivo. Thus MRI has the potential to provide further information to choose an appropriate therapy.

Elena Sophia Schreiber^1,2, Anna-Katinka Bracher¹, Erich Hell³, Johannes Ulrici³, Margrit-Ann Geibel², Leif-Konradin Sailer⁴, and Volker Rasche^1
1Department of Internal Medicine II, University Hospital of Ulm, Ulm, BW, Germany, ²Department of Oral and Maxillofacial Surgery, University Hospital of Ulm, Ulm, BW, Germany, ³Sirona Dental Systems GmbH, Bensheim, Germany, ⁴DOC Praxisklinik im Wiley, Neu-Ulm, Germany

The identification of the culprit lesion in apical periodontitis is often difficult due to the only limited performance of X-ray based techniques. MRI was applied in 30 patients and the results were qualitatively and quantitatively compared with cone beam CT images. MRI appears to reflect the actual size of the lesion much better than X-ray images and hereby an improvement of identification of the apical periodontitis can be achieved.

James F Griffith¹, Defeng Wang¹, Yi-Xiang Wang¹, Shi Lin¹, Min Deng¹, Lai-Shan Tam², and Edmund K Li^2
1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, ²Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong

Currently no method exists to objectively quantify spinal inflammation in ankylosing spondylitis (AS). Typically inflammation in AS involves the vertebral body corner areas. Several subjective scoring systems for spinal inflammation in AS exist. The proposed computerized quantification method automatically isolates the vertebral body corner area as well as the non-corner area of the vertebral body, excluding the basi-vertebral vein area. The entire process can be completed in 8 minutes. This method is reliable, seems sensitive to change and compares to clinical assessment more favorably than subjective assessment.

Conrad Rockel^1,2, Andrew Davis^2,3, Greg Wells⁴, and Michael Noseworthy^1,2
1School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada, ²Imaging Research Centre, St Joseph's Healthcare, Hamilton, Ontario, Canada, ³Medical Physics and Applied Radiation Science, McMaster University, Hamilton, Ontario, Canada, ⁴Faculty of Physical Education and Health, University of Toronto, Toronto, Ontario, Canada

The time course of diffusion within calf muscle following exercise was investigated using DTI in the presence and absence of caffeine. Two trials were performed, each involving two exercise sets one hour apart. In one trial, caffeine was consumed after the first exercise set. Eight DTI volumes were collected both prior to and immediately after each set. In gastrocnemius, post-exercise mean diffusivity(MD) and eigenvalues were approximately baseline, followed by a rapid increase and subsequent gradual decline. Soleus post-exercise MD and eigenvalues increased slightly from rest and appeared stable across time. The presence of caffeine did not affect diffusivity values.

Armen A. Gharibans¹, Curtis L. Johnson¹, Danchin D. Chen¹, Dolores D. Guest², Christie L. Ward³, Bhibha M. Das³, Ellen M. Evans³, and John G. Georgiadis^1
1Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ²Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ³Kinesiology, University of Georgia, Athens, GA, United States

Diffusion tensor imaging (DTI) was used to study microstructural changes in the thigh muscles of elderly, obese women before and after a diet or exercise intervention. Nineteen subjects underwent either a diet or a weight-stable exercise four-month program. Both weight loss and exercise regimens alter muscle microstructure and modify various DTI measures, but exercise impacts muscle quality more than weight loss.

Amanda K. W. Buck¹, Justin Montenegro¹, Jared Godar^1,2, and Bruce M. Damon^1
1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ²Department of Molecular Physiology and Biophysics, Vanderbilt University

Optimization of filter dimensions for HARP processing of cine tagged MRI data of contracting calf muscle with signal loss due to physiologic structures.

Anette Karlsson^1,2, Olof Dahlqvist Leinhard^2,3, Anna Vallin², Thobias Romu^1,2, and Magnus Borga^1,2
1Department of Biomedical Engineering, Linköping University, Linköping, Sweden, ²Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, ³Depts of Radiation Physics, Linköping University and Radiation Physics, UHL County Council of Ostergotland, Linköping, Sweden

We have previously developed methods where intensity normalized water and fat separated images can be used for fat quantification. This approach has now been developed for performing automatic muscle quantification in 3D whole body volumes. A water volume of a subject is used as a prototype where the muscles are segmented manually. The prototype volume is deformed to match the water volume of the target image using non-rigid registration. The muscle mask of the prototype is also deformed giving an automatic muscle mask to the target image which can be used for quantification.

Monika Gloor¹, Evelyn Ilg Hampe², Dirk Fischer³, Oliver Bieri¹, and Arne Fischmann^4
1University of Basel Hospital, Radiological Physics, Basel, Basel, Switzerland, ²Gesundheitsdepartement Basel-Stadt, Basel, Switzerland, ³University of Basel Hospital, Neurology, Basel, Switzerland, ⁴University of Basel Hospital, Neuroradiology, Basel, Basel, Switzerland

Fat quantification based on 2- and 3-point Dixon techniques is a promising measure for clinical trials e.g. in muscular dystrophies, where normal muscle is replaced by fatty and connective tissue. However, it is unclear which chemical components are exactly accounted for by MT-determined fat fractions. In this work, fat content in several meat samples is determined by an extended 2-point Dixon and a 3-point Dixon technique and compared to a chemical analysis of triglyceride and fatty acid content of the samples. The results are of interest for the interpretation of previous and future quantitative MR measurements of muscle fat content.

Noura Azzabou^1,2, Paulo Loureiro de Sousa^1,2, and Pierre G Carlier^1,2
1NMR Laboratory, Institute of Myology, Paris, France, ²NMR Laboratory, CEA, I²BM, MIRCen, IdM, Paris, France

In the field of neuromuscular disorders, muscle water T2 measurement is proposed as a marker of disease progression. However in case of fat infiltrated muscle since T2 values are higher in fat than in water, mono-exponential fits of non-fat-suppressed echo trains will result in T2 values that principally reflect the degree of fat infiltration. Yet fat-suppression often fails over large volumes. Here, we propose a solution to address this issue, based on voxel selection using B1 mapping and tri-exponential deconvolution in non-fat-suppressed multiple echo series, and validate the method in lower limb images of patients.

Claudia Fellner¹, Christine Hechtl¹, Roland Büttner², Okka H. Hamer¹, Christian Stroszczynski¹, and Cornelius Bollheimer^2
1Institute of Radiology, University Medical Center Regensburg, Regensburg, Germany, ²Internal Medicine I, University Medical Center Regensburg, Regensburg, Germany

To assess dietary-induced changes of the muscle, 20 female high fat fed rats (HFR) and 12 female control animals (CR) fed with standard diet as well as 8 male HFR and 14 male CR underwent MRI and MRS at the age of 16 months. Maximum cross sectional area of the M. quadriceps was smaller in HFR compared with CR, HFR yielded increased lipid content and prolonged T2 relaxation times. Although all effects were seen in both genders, dietary-induced differences were significantly more pronounced in male than in female rats indicating relevant gender-depenent differences in our animal model of sarcopenic obesity.

Jasper M Morrow¹, Christopher DJ Sinclair^1,2, Arne Fischmann², Xavier Golay², Tarek A Yousry^1,2, Mary M Reilly¹, Michael G Hanna¹, and John S Thornton^1,2
1MRC Centre for Neuromuscular Diseases, Dept. of Molecular Neurosciences, UCL Institute of Neurology, University College London, London, United Kingdom, ²Academic Neuroradiological Unit, Dept of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom

We measured lower-limb thigh and calf muscle fat-fractions by 3-point Dixon MRI in 20 Charcot-Marie-Tooth disease 1A (CMT1A) patients, 20 patients with inclusion body myositis (IBM) and 28 healthy controls. Mean %fat-fractions were increased in both patient groups relative to controls for all calf muscles (p<0.01) and in IBM patients for all thigh muscles (p<0.001). Relevant remaining cross-sectional muscle area, a composite measure accounting for both muscle atrophy and fat replacement, was highly correlated (R=0.57-0.90, p <0.001) with accurate functional measures of knee and ankle strength. Dixon lower-limb muscle-fat assessment shows promise as a trial outcome measure in neuromuscular diseases.

Barbara Janssen¹, Nicoline Voet², Rob Arts¹, Christine Nabuurs¹, George Padberg³, Alexander Geurts², Baziel van Engelen³, and Arend Heerschap^1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ²Rehabilitation, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ³Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

To assess natural progression towards a diseased state in FSHD-patients, and effects of Cognitive Behavioral Therapy and Aerobic Exercise Training (AET) we used muscle fraction measured by 1H¬-MRI of the thigh muscles as non-invasive biomarkers. A decrease in muscle fraction, corresponding to an increase in fatty infiltration, could be noticed in controls after a four month period of usual care. This increase was largest in intermediate affected muscles. Interventions appeared to beneficial to patient since no significant increase in fat infiltration could be noticed after four months after intervention, heavily affected muscles even showed an increase in muscle fraction.

Curtis L. Johnson¹, Danchin D. Chen¹, Diego Hernando², Dolores D. Guest³, Christie L. Ward⁴, Bhibha M. Das⁴, Ellen M. Evans⁴, and John G. Georgiadis^1
1Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ²Radiology, University of Wisconsin, Madison, WI, United States,³Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ⁴Kinesiology, University of Georgia, Athens, GA, United States

Proton magnetic resonance spectroscopy (MRS) was used to study lipid storage in the thigh muscles of elderly, obese women before and after a diet or exercise four-month intervention program. Subjects were divided in two groups, a diet group who lost 10% in body weight or a weight stable exercise group. The exercise group showed significant changes in EMCL and total lipid concentrations, with no change in IMCL concentration. The diet group showed no significant changes in lipid storage with intervention.

Vladimír Mlynárik¹, Maxime Pellegrin², Cristina Cudalbu¹, Lucia Mazzolai², and Rolf Gruetter^1,3
1Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland, ²Service of Angiology, University Hospital of Lausanne, Lausanne, Switzerland, ³Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

Diminished perfusion in peripheral arterial disease leads to the development of ischemia, which is thought to initiate angiogenesis, arteriogenesis and enhanced muscle metabolism. Our model of ligating right common iliac artery in mice led to a significant decrease of PCr/-ATP measured by localized phosphorus MRS in femoral muscles of the operated leg compared to sham-operated controls one week after surgery. The PCr/-ATP ratio was also reduced in the contralateral leg. Five weeks after operation this ratio increased in both legs to levels slightly higher than those in sham-operated animals. There was no significant difference between sedentary and treadmill-exercised animals.

Ladislav Valkovic^1,2, Barbara Ukropcova³, Marek Chmelik¹, Miroslav Balaz³, Martin Tkacov¹, Wolfgang Bogner¹, Albrecht Ingo Schmid⁴, Ivan Frollo², Iwar Klimes³, Erika Zemkova⁵, Jozef Ukropec³, Siegfried Trattnig¹, and Martin Krššák^6
1MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria, ²Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, ³Obesity section, Diabetes and Metabolic Disease Laboratory, Institute of Experimental Endocrynology, Slovak Academy of Sciences, Bratislava, Slovakia, ⁴Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ⁵Faculty of Physical Education and Sport, Commenius University, Bratislava, Slovakia, ⁶Division of Endocrynology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria

In this study different parameters of muscle energy and oxidative metabolism in quadriceps of overweight to obese healthy subjects (n=8) were compared. Maximal oxidative flux (Q_max) was measured by time resolved ³¹P-MRS during post exercise recovery. Six minutes of exercise at ~30% of MVC resulted in substantial decrease of PCr without alteration of pH. Mean value of Q_max reached 0.48±0.10 mM/s. Basal flux through ATPase (F_ATP) at rest was measured by magnetization transfer ³¹P-MRS experiment. Mean value of F_ATP was 0.23±0.09 mM/s. At this stage positive trend, but no significant correlation (r=0.535, p=0.19) was detected between Q_max and F_ATP.

Mary Charlotte Stephenson¹, Frances Gunner², Paul L Greenhaff², Peter G Morris¹, and Ian A MacDonald^2
1SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, ²School of Biomedical Sciences, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Ingestion of a high molecular weight glucose polymer (HMW) with low osmolality leads to greater early increases in blood glucose and insulin compared with a glucose polymer with lower molecular weight (LMW) and higher osmolality. This study aims to use ¹³C MRS to measure differences in muscle glycogen resynthesis rates following ingestion of three different drinks: HMW, LMW, and flavoured water. Despite significant increases in glycogen levels following HMW and LMW ingestion, rates of glycogen resynthesis were smaller than expected and were not significantly different between the two glucose polymers. No glycogen resynthesis was found following ingestion of flavoured water.

Erin Leigh MacMillan¹, Chris Boesch¹, and Roland Kreis^1
1Depts Clinical Research and Radiology, University of Bern, Bern, Switzerland

Non-water suppressed proton MRS via the metabolite cycling technique was applied to human soleus and tibialis anterior muscles with short TE PRESS at 3T revealing additional features in the downfield region. In addition, magnetization transfer of these downfield resonances, and the upfield creatine CH2 and CH3 peaks, was investigated by selectively inverting the water resonance with increasing mixing times. Changes in magnetization of the downfield resonances and creatine peaks in the soleus were similar to those in the tibialis anterior, which exhibits residual dipolar coupling. These results may help to gain a deeper understanding of underlying magnetization transfer phenomena.

Benjamin Leporq¹, Yann Le Fur², Patrick Cozzone², Olivier Beuf¹, and David Bendahan^2
1CREATIS; CNRS UMR 5220; INSERM U1044; INSA-Lyon; UCBL Lyon 1, Villeurbanne, Rhône-Alpes, France, ²CRMBM; CNRS UMR 6612; Université Aix-Marseille, Marseille, PACA, France

Due to its sensitivity to key processes in the diseased muscle such as edema and fat infiltration, MRI is emerging as a suitable quantitative method which could provide reliable surrogate markers of disease severity and progression. The aim of this work was to evaluate the feasibility of 3D segmentation of fat and muscular tissue using a triple-angles multiple gradient-echo acquisition. Our approach includes a complex-based technique for fat volume fraction (FVF) quantification with independent measurements of fat and water T1 and T2*and corrections from T1-related bias and spectral complexity of fat.

Claudia Fellner¹, Christine Hechtl¹, Roland Büttner², Okka H. Hamer¹, Christian Stroszczynski¹, and Cornelius Bollheimer^2
1Institute of Radiology, University Medical Center Regensburg, Regensburg, Germany, ²Internal Medicine I, University Medical Center Regensburg, Regensburg, Germany

Dietary-induced changes on quadriceps muscles were investigated in 20 female high fat fed rats (HFR) and 12 control rats (CR) fed with standard diet, who underwent MRI and MRS at the age of 6, 12, and 16 months. Until the age of 16 months, increased accumulation of body weight in HFR relative to CR was accompanied by a larger lipid content in quadriceps muscles – without changing the cross sectional area of the muscle. During this period of time, age-related and dietary-induced changes of the T2 relaxation times in the muscle can not be explained exclusively by an increased lipid content.

Andreas Petrovic^1,2, Kathrin Ogris³, Eva Hassler^3,4, Rudolf Stollberger⁵, and Eva Scheurer^3,4
1Institute of Medical Engineering, University of Technology Graz, Graz, Austria, Austria, ²Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria, Austria,³Ludwig Boltzmann Institute for Clinical Forensic Imaging, ⁴Medical University Graz, ⁵University of Technology Graz

In legal medicine the detection of hematomas in subcutaneous fatty tissue and especially the estimation of their age is highly relevant. The time dependent development of the MRI signal of blood is well known and described in the literature for intracranial hematomas for which a semi-quantitative staging scheme was defined. In this work we continuously measured the relaxation times T1, T2 and T2* of human blood samples to characterize the actual time course. Our measurements confirm the findings from the literature but also further provide valuable insight on the interdependence of the relaxation parameters.

Nathan D Bryant¹, Ke Li¹, Mark Does², Daniel Gochberg¹, Thomas Yankeelov¹, Jane Park^3,4, and Bruce Damon^1,4
1Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ²Biomedical Engineering, Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, ³Molecular Physiology and Biophysics, Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ⁴Co-Senior Author

Healthy skeletal muscle was compared to inflammation in the contralateral quadriceps muscles of mice. T2, indices of diffusion, quantitative magnetization transfer, and dynamic contrast enhancement (DCE) MRI data were acquired during the same imaging session. The edematous muscle exhibited a significant increase in T2, apparent diffusion coefficient (ADC) and the DCE estimate of the interstitial volume, while a concomitant decrease was observed in the proton pool ratio. The aim of this study is to provide a basis for understanding how inflammation, in isolation from complex pathology, influences the quantitative MRI parameters that are commonly used to characterize muscle disease.

Robert L. Janiczek^1,2, Christopher D.J. Sinclair², Giulio Gambarota³, Xavier Golay², Rexford D. Newbould⁴, and John S. Thornton^2
1Global Imaging Unit, GlaxoSmithKline, London, United Kingdom, ²Institute of Neurology, University College London, London, United Kingdom, ³Pharmaceutical and Biological Sciences, Université de Rennes 1, Rennes, France, ⁴Imanova Ltd., London, United Kingdom

A reduced magnetization transfer (MT) effect has been observed in muscles affected by neuromuscular diseases due to a combination of lipid infiltration, edema, and/or macromolecular differences relative to healthy muscle. Lipid infiltration can therefore mask MT changes due edema and biologically important macromolecular abnormalities. This work presents a technique, MT-IDEAL, that combines a chemical-species separation imaging technique, IDEAL, with an MT imaging acquisition. MT-IDEAL uses multiple echoes to increase SNR as well as produce fat fraction, T₂^*, and water-isolated MTR maps with no scan time penalty.

Sung-Hong Park¹, and Kyongtae Ty Bae^1
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States

In this article we evaluated the feasibility of alternate ascending/descending directional navigation (ALADDIN), a new imaging technique that provides interslice perfusion-weighted and MT asymmetry images, on human skeletal muscle. Subtraction artifacts in ALADDIN MT asymmetry images were suppressed by averaging signals over the readout gradient polarities. ALADDIN PW and MT asymmetry signals measured in muscle were about 10% and 30%, respectively, of those in brain, while MT ratio of muscle was similar to that of brain. Further studies are necessary to investigate clinical usefulness of simultaneous acquisition of blood flow, MT asymmetry, and MT ratio with ALADDIN in skeletal muscle.

Erik Hedstrom^1,2, Ashish S Patel^2,3, Tobias Voigt^1,4, Bijan Modarai^2,3, Tobias Schaeffter^1,2, Alberto Smith^2,3, and Eike Nagel^1,2
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, Greater London, United Kingdom, ²BHF Centre of Research Excellence and NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Fo, London, United Kingdom, ³Academic Department of Surgery, King's College London, London, Greater London, United Kingdom, ⁴Philips Research, Clinical Research Europe

BOLD MRI of lower limb muscle has shown low reproducibility using relatively low-resolution EPI-readout GRE sequences, which may partly be related to partial volume effects. We propose a high-resolution GRE sequence without EPI readout to decrease partial volume effects and test it in elderly men without limb disease during transient ischaemia induced by cuffing to suprasystolic pressure. We show low intrascan variability and high interscan reproducibility for measurement of T2* in limb muscle, indicating that serial assessment of limb muscle oxygenation is possible.

Paul Kennedy¹, Scott Semple¹, Calum Gray¹, Annette Cooper¹, Eric Barnhill¹, Colin Brown², David Donaldson³, Edwin van Beek¹, Pete Hoskins⁴, Dieter Klatt⁵, Ingolf Sack⁵, Jürgen Braun⁵, Carolyn Greig⁴, Angus Hunter⁶, and Neil Roberts^1
1Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, United Kingdom, ²The Mentholatum Company, East Kilbride, Glasgow, United Kingdom, ³Department of Psychology, University of Stirling, Stirling, United Kingdom, ⁴University of Edinburgh, ⁵Charité University, Berlin, Germany, ⁶Health and Exercise Sciences Research Group, University of Stirling, Stirling, United Kingdom

We present our ongoing work on the investigation of human skeletal muscle using MRI. We outline the variations in muscle morphology seen and how they correlate with stiffness measurements obtained by magnetic resonance elastography.

David K.W. Yeung¹, James F Griffith², Heather T Ma^2,3, and Alvin F.W. Li^4
1Imaging and Interventional Radiology, Prince of Wales Hospital, Shatin, HKSAR, Hong Kong, ²Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, Hong Kong, ³Department of Electronic and Information Engineering, Harbin Institute of Technology, China, ⁴Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin

Muscle perfusion may be studied using the BOLD technique. This method relies on an air-cuff to induce reactive hyperemia. However, oxygen in air is a paramagnetic molecule and whether an inflated air-cuff has an effect on T2* signal measurement is not known. This study attempts to answer this question and offers solutions to correct for aberrant T2* signal changes.

Yasuhiko Terada¹, Saki Kono¹, Daiki Tamada¹, Tomomi Uchiumi¹, Katsumi Kose¹, Ryo Miyagi², Eiko Yamabe², and Hiroshi Yoshioka^2
1Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan, ²Department of Radiological Sciences, University of California Irvine, Irvine, CA, United States

To measure child�fs skeletal age, which is a standard measure of child�fs growth status, an open compact MRI system was optimized for child�fs hand imaging. Left hands of 93 healthy children volunteers were imaged using a 3D coherent gradient-echo sequence. Despite the limited measurement time (2 min 44 s), each bone was well resolved in the MRI images, revealing the validity of the system. Furthermore, segmented volume of carpal bones highly correlates with skeletal age (r = 0.904 for boys and 0.917 for girls). This reveals that the bone volume is a new, good indicator of child�fs maturity.

Fredy Visser^1,2, Mies Korteweg¹, Michel Italiaander¹, Peter Luijten¹, and Dennis Klomp^1
17 Tesla, UMC, Utrecht, Utrecht, Netherlands, ²Philips Healthcare, Best, Brabant, Netherlands

The aim of this study is to develop a High Resolution TSE PD-weighted sequence for ankle imaging. We show that routine clinical TSE sequence in MSK is feasible at 7T . The combination of the high SNR at 7Tesla and a 32 channel high density flexible receive array has the potential to make the next step forward in High Resolution musculoskeletal imaging.

Thomas Lange¹, Julian Maclaren¹, Michael Herbst¹, Kaywan Izadpanah², and Maxim Zaitsev^1
1Department of Radiology, University Medical Center Freiburg, Freiburg, Germany, ²Department of Orthopedic and Trauma Surgery, University Medical Center Freiburg, Freiburg, Germany

Since chondromalacia is associated with altered mechanical cartilage properties, the response of tissue parameters such as cartilage thickness or relaxation times to loading is of particular interest. However, knee MRI studies with in situ loading are hampered by subject motion. Using prospective motion correction based on optical tracking, MRI of the patellofemoral joint with in situ mechanical loading is demonstrated. Results indicate that the rigid-body approximation required for prospective correction with optical motion tracking is fulfilled for the patellofemoral compartment and that with presaturation of the posterior knee compartment an image quality similar to an unloaded setup can be obtained.

Robert D. Darrow¹, Eric W. Fiveland¹, Xiaodong Tao², Ambey Govenkar³, Xiaofeng Liu¹, W. Thomas Dixon¹, Michael S. Jansen⁴, and Ileana Hancu^1
1GE Global Research, Niskayuna, N.Y., United States, ²GE Healthcare, Beijing, China, ³Extenprise, Inc., Pune, India, ⁴GE Healthcare, Milwaukee, WI, United States

An automated landmark system, positioning anatomy of interest at magnet isocenter, can simplify a MR exam. It can also ensure automatic scan plane prescription algorithms are provided with the correct input. A system is presented that localizes the imaging coil along the Superior/Inferior axis, enabling automatic translation of coil center from home position to magnet isocenter. Once the anatomy of interest is at isocenter, scout images are acquired and processed, localizing the coil relative to the patient, and enabling computation of the scan volume center. This dual localization permits imaging with optimal positioning, while completely eliminating the manual landmark.

Wingchi Edmund Kwok^1,2, Zhigang You¹, Johnny Monu¹, Gwysuk Seo¹, and Amy Lerner^3
1Department of Imaging Sciences, University of Rochester, Rochester, NY, United States, ²Rochester Center for Brain Imaging, University of Rochester, Rochester, NY, United States, ³Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States

To address insufficient resolution and chemical-shift artifacts that can hinder MRI evaluation of arthritis in finger joints, an interleaved water-fat (IWF) sequence without chemical-shift artifacts and a dedicated RF coil were used for high-resolution finger MRI. In this study, we evaluated this technique in the depiction of bone structures by correlating MR images of cadaver fingers with micro-CT that served as the gold standard. IWF images provided accurate depiction of bone structures and abnormalities as seen in micro-CT, and avoided false appearance of erosions. High-resolution IWF imaging should be useful for the diagnosis, treatment assessment and pathogenesis studies of arthritis.

Karupppasamy Subburaj¹, Deepak Kumar^1,2, Richard B Souza^1,2, Hamza Alizai¹, Xiaojuan Li¹, Thomas M Link¹, and Sharmila Majumdar^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, CA, United States

The mechanical function of the meniscus largely depends on the structural and molecular integrity of its matrix, composed of a network of collagen fibers (Type I) immobilizing proteoglycans (PG). Recent studies have shown the potential of quantitative MR imaging, including T2 and T1ρ quantifications for studying biochemical composition of meniscus. The purpose of this study was to determine the response of PG and collagen, which are responsible for the compressive stiffness and tensile strength of meniscus [5], respectively, to static- and cyclic-loading using magnetic resonance (MR) relaxation times (T1ρ and T2) in young healthy adults.

Michael Carl¹, and Jiang Du^2
1GE Healthcare, San Diego, CA, United States, ²University of California, San Diego, United States

We developed adiabatic pulses for non-selective inversion, which actively drive the magnetization vector along a path parallel to the effective B1 trajectory using driven adiabatic inversion (DAI) pulses. These pulses may play a particularly important role in IR prepared 3DUTE imaging, where the minimum TR (and hence scan-time) is limited by the SAR imparted by the adiabatic inversion pulses. Simulations, and phantom test were used to verify the inversion efficiency and SAR performance compared to conventional Silver-Hoult IR pulses.

Michael Carl¹, and Graeme McKinnon^2
1GE Healthcare, San Diego, CA, United States, ²GE Healthcare, Waukesha, WI, United States

There exists a variety of inconsistent definitions of TE for short echo time sequences throughout the literature. We investigate via theoretical analysis, Bloch simulations, and phantom experiments an appropriate definition of TE for short echo time FID sequences. Erroneous definitions of TE will underestimate the amount of T2 decay and off-resonance phase evolutions, which may result in errors in assessing T2 and/or resonance frequency of tissues.

Delphine Perie^1,2, Mohamed Aissiou^1,2, Julien Gervais^1,2, Francois Trocchu¹, Gilles Beaudoin³, and Guillaume Gilbert^4
1Mechanical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada, ²Research center, CHU Sainte-Justine, Montreal, Quebec, Canada, ³Physics and Biomedical Engineering, CHUM Hopital Saint-Luc, Montreal, quebec, Canada, ⁴MR Clinical Science, Philips Healthcare, Cleveland, OH, United States

The aim of this study is to validate the reconstruction of 2D and 3D images from low to high spatial resolution. We performed two quantitative MR acquisitions (low and high resolution) on bovine discs. We adopted the Dual-Kriging formulation and we introduced the technique of progressive Kriging. For each MR sequence, Kriging was compared to other interpolation techniques including the zero padding, nearest neighbour, bilinear and bicubic techniques. Progressive Dual-Kriging is a flexible technique that can be optimized to interpolate 2D and 3D data based on the signal distribution. The computation is relatively fast and the interpolation is better fitted to the signal distribution as opposed to other techniques.

Nikolaus M. Szeverenyi¹, and Graeme M. Bydder^1
1Radiology, University of California, San Diego, CA, United States

Residual dipolar coupling (RDC) provides an important contrast mechanism when imaging fibrocartilage. The presence of RDC produces change in T2* values and gives rise to the magic angle effect, providing angle dependent contrast between fiber structures. RDC should be viewed as a fundamental measurable tissue parameter, similar to a diffusion rate or T1 value. We have developed an imaging technique allowing the evaluation of this parameter on a per voxel basis. The RDC value provides a sensitive indicator reflecting the structure of fibrocartilage tissue, e.g. direction and distribution of fibers, how much collagen is present and state of hydration.

Monika Barczewska¹, Joanna Wojtkiewicz¹, Aleksandra Habich¹, Miroslaw Janowski^2,3, Zbigniew Adamiak⁴, Piotr Holak⁴, Hubert Matyjasik⁴, Jeff WM Bulte^2,3, Wojciech Maksymowicz¹, and Piotr Walczak^2,3
1Neurology and Neurosurgery, Division of Neurosurgery, Faculty of Medical Sciences, University of Warmia and Mazury, Olsztyn, Poland, ²Radiology and Radiological Science, Johns Hopkins University, ³Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, United States, ⁴Surgery and Radiology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Degenerative disc disease is related to substantial morbidity and no treatment exists that can restore disc structure. Stem cell-based therapy is a new promising therapeutic approach; however, for the use of stem cells a precise and minimally invasive cell delivery procedure is of critical importance. We show here that MR monitoring can be used to verify the accurate delivery of cells and provide a detailed picture of initial cell engraftment and biodistribution in a clinically relevant fashion.

Alexander C. Wright¹, Sung M. Moon^1,2, Jonathon H. Yoder², Edward J. Vresilovic², and Dawn M. Elliott^2
1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States

High-resolution MRI (200 µm isotropic) at 7T was used to visualize the anatomy of the sub-structures of the human intervertebral disc, and T1 and T2 relaxation parameter maps were acquired on a specimen. Based on these, a T1-T2 cluster analysis revealed distinct differentiation of the disc sub-structures. A similar trend was observed even for T1- and T2-weighted images. These concepts were tested in vivo at 3T in order to assess their potential role as a grading scheme for disc degeneration.

Gopal Varma¹, Fotini Kourtelidis¹, Ananth Madhuranthakam^1,2, David B Hackney³, Robert E Lenkinski^1,2, and Elena Vinogradov^1,2
1Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, ²Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ³Neuroradiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

Early signs of intervertebral disc (IVD) degeneration are associated with a decrease in glycosaminoglycan (GAG) content. Recently, chemical exchange saturation transfer, i.e. gagCEST, has been used to assess GAG distribution in vivo. This work looks at application of gagCEST for analysis of IVDs from the lumbar spine of volunteers of varying age. The IVDs are grouped based on Pfirrmann grading, as well as age, and a decrease in gagCEST contrast is observed with increasing disc degeneration.

Vladimir Juras^1,2, Christina Pressl¹, Iris-Melanie Noebauer-Huhmann¹, Stefan Zbyn¹, Pavol Szomolanyi¹, Stephan Domayer³, Ivan Frollo², and Siegfried Trattnig^1
1Department of Radiology, MR Centre of Excellence, Medical University of Vienna, Vienna, Austria, Austria, ²Department of Imaging Methods, Institute of Measurement Science, Bratislava, Slovakia, ³Department of Orthopedics, Medical University of Vienna, Vienna, Austria, Austria

Sodium MRI using 3D-GRE has been investigated as a possible marker for Achilles tendinopathy. Achilles tendinopathy is associated with an increase in proteoglycans and can be detected by sodium MR imaging which has been validated by in vitro study. Moreover, it was shown that the Achilles tendon is diffusely affected in Achilles tendinopathy.