Masami Yoneyama¹, Takayuki Sakai², Shuo Zhang³, Daichi Murayama², Hajime Yokota⁴, Yansong Zhao⁵, Shinji Saruya⁶, Masashi Suzuki⁶, Atsuya Watanabe^7,8, Mamoru Niitsu⁶, and Marc Van Cauteren^9
1Philips Japan, Tokyo, Japan, ²Department of Radiology, Eastern Chiba Medical Center, Chiba, Japan, ³Philips Healthcare, Hamburg, Germany, ⁴Department of Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan, ⁵Philips Healthcare, Cleveland, OH, United States, ⁶Department of Radiology, Saitama Medical University, Saitama, Japan, ⁷Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Chiba, Japan, ⁸General Medical Services, Graduate School of Medicine, Chiba University, Chiba, Japan, ⁹Philips Healthcare, Best, Netherlands

3D high-resolution magnetic resonance imaging (MRI) is clinically essential for an accurate assessment of subtle pathophysiological changes in different anatomies. However, long exam time remains a practical challenge that requires additional scans for either complementary quantitative parametric mapping or morphological information for clinical diagnosis. In this study, we introduce a novel method termed Multi-Interleaved X-prepared TSE with inTUitive RElaxometry (MIXTURE) for simultaneous morphological and quantitative imaging with volumetric isotropic resolution within one single scan and demonstrate the approach in multi-contrast quantitative knee imaging with direct T2- or T1ρ-mapping.

Christian Waldenberg¹, Stefanie Eriksson¹, Hanna Hebelka², Helena Brisby³, and Kerstin Magdalena Lagerstrand^1
1Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden, ²Department of Radiology, University of Gothenburg, Gothenburg, Sweden, ³Department of Orthopaedics, University of Gothenburg, Gothenburg, Sweden

Annular tears of intervertebral discs (IVDs) are associated with ingrowth of nerve endings with the potential to cause discogenic pain. We propose a novel non-invasive workflow for detecting annular tears and determining its location based on conventional magnetic resonance imaging (MRI). 124 IVDs in 44 patients with low back pain were included. Based on MRI, texture analysis and neural networks, a classification algorithm and workflow for determining the presence and position of annular tears were proposed. Excellent classification sensitivity of 100% and specificity of 93% were reached. The position of the tears was correctly determined in 67% of the IVDs.

Lina Lin¹, Lutian Bai¹, Qun Cheng², Manuel Schneider³, Marcel Dominik Nickel³, Caixia Fu⁴, Guangwu Lin¹, and Shihong Li^1
1Department of Radiology, Huadong Hospital, Fudan University, Shanghai, China, ²Department of Osteoporosis, Huadong Hospital, Fudan University, Shanghai, China, ³MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany, ⁴Application Development, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China

This study is to explore the application value of fatty acid composition (FAC) measurements in the diagnosis of osteoporosis. 39 subjects who underwent dual-energy X-ray absorptiometry (DXA) and lumbar magnetic resonance imaging on a 3T scanner were included. We found that FF value was negatively correlated with T value (P < 0.05, r = -0.371), and SF value was positively correlated with T value (P < 0.05, r = 0.399). The PUF value of the osteopenia group was significantly higher than that of the osteoporosis group（P < 0.05）and normal bone mass group（P < 0.05）. 

Yayun Ji¹, Jianqiang Fang¹, Binyu Zhang¹, Siyuan Mi¹, Weiyin Vivian Liu², Weian Zhao¹, and Liheng Ma^3
1Xianyang Central Hospital, Xianyang, China, ²MR research, GE Healthcare, Beijing, China, ³The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, China

This study aims to investigate if advanced UTE T2* Mapping MRI quantitative sequence could sensitively assess the early changes in the biochemical components of the cartilage endplate. This might explain the pathological mechanism of cartilage endplate injury, that is, bone marrow fat content increased in vertebral body of degenerated intervertebral disc. To sum up, UTE T2* Mapping could a potential imaging tool to early diagnose cartilage endplate changes and assist clinical prevention of lumbar intervertebral disc degeneration at an earlier stage.

Cui Ren¹, Qing Li², Stefan Sommer^3,4, Qiao Zhu¹, and Huishu Yuan^1
1Radiology, Peking University Third Hospital, Beijing, China, ²MR Collaborations, Siemens Healthcare Ltd, Shanghai, China, ³Siemens Healthcare, Zurich, Switzerland, ⁴Swiss Center for Musculoskeletal Imaging (SCMI), Zurich, Switzerland

The aim of this study was to evaluate the performance of a 3D-UTE sequence in the detection of sacroiliac joint cartilage and bone cortex abnormalities in patients with clinically confirmed ankylosing spondylitis. T2* derived from 3D-UTE displayed potential as a quantitative measure to diagnose ankylosing spondylitis.

Victor Babu Kassey^1,2,3,4, Matthias Walle¹, Jonathan Egan¹, Diana Yeritsyan¹, Yaotang Wu^2,3,4, Brian D Snyder^2,4, Edward Rodriguez^1,2, Jerome Ackerman^2,5, and Ara Nazarian^1,2,4
1Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States, ²Harvard Medical School, Boston, MA, United States, ³Massachusetts General Hospital, Charlestown, MA, United States, ⁴Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA, United States, ⁵Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States

Bone matrix and mineral densities (BMD) are important parameters to identify bone diseases such as osteoporosis and osteomalacia. Micro-CT, CT, and DXA scans provide bone mineral densities but not bone matrix. In this study, a non-invasive, radiation-free, and clinically proven combined 1H/31P MRI method was developed to measure bone matrix and mineral densities from rat bones from the same volume-of-interest sequentially in a single session. A custom-designed home-made double-tuned single volume coil was designed for 7T, and 1H/31P ZTE rat bone images were obtained, auto-registered, bone matrix and mineral densities were computed quantitatively, and osteoporosis and osteomalacia were successfully identified.

Yijie Fang¹, Wenjun Yu¹, Long Qian², and Shaolin Li^1
1The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China, ²MR Research, GE Healthcare, Beijing, China

To explore the value of Synthetic magnetic resonance imaging (Sy MRI) in the quantitative monitoring of knee joint structural changes and cartilage of amateur marathon runners before and after the whole marathon. Twenty-six knee joints of healthy volunteers who took part in the marathon were scanned by Sy MRI technology one week before the race and within 48 hours after the race. The values of T1, T2 and PD of knee cartilage in whole and different regions before competition were higher than those of 48 hours after the marathon, and the difference was statistically significant

Baiyan Jiang¹, Ki-wai, Kevin Ho², Xiao Fan¹, Jian Hou¹, Chun-man Lawrence Lau², James Griffith¹, and Weitian Chen^1
1Imaging & Interventional Radiology, The Chinese University of Hong Kong, Sha Tin, Hong Kong, ²Orthopaedics & Traumatology, The Chinese University of Hong Kong, Sha Tin, Hong Kong

The measurement of R1rho (1/T1rho) spectrum and its asymmetry have several advantages over conventional CEST MTR asymmetry in probing chemical exchange effect. Previous studies have reported that AC-iTIP is a robust approach to obtain R1rho-spectrum and R1rho asymmetry. However, an accurate B0 map is required to perform R1rho asymmetry. In this work, we fit the entire R1rho spectrum to a mathematical expression and directly acquire the pool population parameter pb. A preliminary in vivo scan on 4 osteoarthritis patients was performed and AC-iTIP shows promising results in probing GAG content in knee cartilage at 3.0T.

Hanqi Wang¹, Qing Li², Stefan Sommer^3,4, and Yong Lu^1
1Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, ²MR Collaboration, Siemens Healthcare Ltd., Shanghai, China, Shanghai, China, ³Siemens Healthcare, Zurich, Switzerland, Zurich, Switzerland, ⁴Swiss Center for Musculoskeletal Imaging (SCMI), Balgrist Campus, Zurich, Switzerland, Zurich, Switzerland

UTE sequences were utilized to quantitatively assess deep and superficial cartilage. Deep cartilage T2* values demonstrated a significant difference in different load-bearing regions while there was no statistical difference for superficial cartilage. No significant change in T2* value of deep cartilage after activity was observed, while T2* values of the superficial layer decreased after activity in both the medial tibial and lateral femoral cartilage, indicating that different bio-mechanical properties exist within the deep and superficial cartilage.

Muhammad Ali Raza Anjum¹, Anshuman Swain ¹, Johannes Leisen², Felix Gonzalez¹, and David Reiter ^1
1Emory University, Atlanta, GA, United States, ²Georgia Tech, Atlanta, GA, United States

Bi-component T2* modelling is widely applied to tendon to elucidate structural and biochemical properties of tissue. This model does not incorporate magnetization exchange between collagen-bound water and interstitial water pools. This study reports intermediate exchange-rates compared with respective pool relaxation rate estimates, in ex vivo bovine and ovine Achilles tendon, measured using T2–T2 correlation NMR. Intermediate exchange causes the bi-component model to underestimate the population of the rapidly-relaxing pool and overestimate relaxation rates and the population of the slowly-relaxing pool. The two-pool exchange model could be more specific to structural and biochemical changes in tendon with pathology.  

Francesco Caliva¹, Victor Kaiyang Cheng², Rutwik Shah¹, Misung Han¹, Sharmila Majumdar¹, and Valentina Pedoia^1
1University of California San Francisco, San Francisco, CA, United States, ²University of California Berkeley, Berkeley, CA, United States

We propose an Adversarial Robust Training (ART) strategy to overcome the problem with accelerated MRI models, which are prone to missing small yet clinically relevant features. We introduced small, difficult to reconstruct synthetic features to undersampled MRIs and encouraged their reconstruction through robust training. To assess generalizability of our technique to real world applications, we annotated morphological features relevant to musculoskeletal disease diagnosis on images in the FastMRI dataset and tested ART. Overall, the approach has potential to reduce network instability and improve reliability and fidelity in image reconstruction.

Yu Song¹, Qingwei qing Song², Yingkun Guo¹, Gang Ning¹, Xuesheng Li¹, and Yu Song^3
1Department of Radiology, West China Second University Hospital, Sichuan University, Chengdu, China, ²Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China, ³Department of Radiology, West China Second University, Sichuan University, Chengdu, China

 The changes of adipose tissue in bone marrow will directly affect the changes of bone marrow composition. 3D mDixon Quant technology is a new method for precise fat quantification developed by Philips. It automatically generates high-quality FF and T2 * mapping maps by multi-echo acquisition combined with 7 peak fat model and T2 * correction, so as to achieve accurate and rapid quantification of bone marrow fat content.

Sebastian Werner¹, Bernhard Krauss², and Marius Horger^1
1Radiology, University Hospital Tuebingen, Germany, Tuebingen, Germany, ²Siemens Healthineers, Forchheim, Germany

Retrospective quantitative evaluation of 103 focal osteolytic lesions of the axial skeleton in virtual-non-calcium bone marrow images of 32 multiple myeloma patients in correlation to hematologic disease status, T1w signal intensity and ADC. Virtual-non-calcium bone marrow imaging allows differentiation between overall active and inactive disease with higher attenuation signifying an increasing likelihood of active disease. This is supported by a significant positive correlation between the attenuation and the ADC, as well as a corresponding inverse correlation to T1w signal intensity.

Kirstin D Olsen¹, Lumeng Cui¹, Brennan E Berryman², Ives R Levesque³, and Emily J McWalter^2
1Biomedical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ²Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ³Medical Physics, McGill University, Montreal, QC, Canada

The objective of this research was to determine if quantitative magnetization transfer (qMT) MRI can assess knee meniscus tissue health. Cadaver knee menisci underwent qMT assessment, biochemical content assessment, and histological scoring. Weak correlations were found between T_1f and collagen content, T_1f and histology score, and the histology scores and T_2f and T_2b. A moderate correlation was found between T_2f and collagen content. qMT shows promise as a measure of meniscal tissue health but future studies with more severely damaged tissue are required to elucidate relationships between qMT and measures of meniscal content and health.

Andrew S. Nencka¹, Peter S. Johnson¹, and Kevin M. Koch^1
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States

An average proton density weighted template of the hip with arthroplasty was developed, and multi-spectral images from patients acquired at both 1.5T and 3.0T were registered to it. As a proof-of-concept, maps of residual metal artifact were transformed into the template space and, for different implant compositions, probability maps of residual artifact were generated. Ceramic implants exhibit minimal cross-field artifact differences, while metal-on-metal implants show more profound differences and metal-on-poly implants exhibit more moderate differences. This template and registration software lays the foundation for future quantitative analysis of cross-session and cross-subject imaging of hip arthroplasty.

Zhao Wei^1,2,3, Hyungseok Jang¹, Zubiad Ibrahim¹, Mohammadamin Cheraghi¹, Graeme M. Bydder¹, Wenhui Yang^2,3, and Ya-Jun Ma^1
1Department of Radiology, UC San Diego, San Diego, CA, United States, ²Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, ³University of Chinese Academy of Sciences, Beijing, China

To improve the time efficiency for cortical bone T₁ measurement on clinical scanners, we proposed a new method which fits the datasets of 3D ultrashort echo time actual flip angle imaging (UTE-AFI) and UTE with a single TR (UTE-STR) simultaneously (UTE-AFI-STR). The results show that the UTE-AFI-STR can measure the T₁ of cortical bone accurately and more efficiently than the UTE-AFI-VTR method.

Rossana Terracciano^1,2, Yareli Carcamo-Bahena¹, Xiaowei Zou³, Joshua D. Harris⁴, Bradley Weiner⁴, John Scott Labis⁵, Nakul Gupta⁵, and Carly S. Filgueira^1,6
1Nanomedicine, Houston Methodist Research Institute, Houston, TX, United States, ²Electronics and Telecommunications, Politecnico di Torino, Torino, Italy, ³Siemens Medical Solutions USA Inc, Malvern, PA, United States, ⁴Orthopedic Surgery, Houston Methodist Research Institute, Houston, TX, United States, ⁵Clinical Radiology, Houston Methodist Research Institute, Houston, TX, United States, ⁶Cardiovascular Surgery, Houston Methodist Research Institute, Houston, TX, United States

No medical therapies have been shown to halt or slow the progression of post-traumatic osteoarthritis (PTOA), which develops after acute/repetitive injury to a joint. Improvements in non-invasive methods to assess PTOA will help diagnose stages for early clinical interventions. Rabbits offer a translationally relevant animal model where anterior cruciate ligament (ACL) injury allows for monitoring PTOA progression, determining a treatment window for early invention. In this work, we leveraged the high signal-to-noise ratio (SNR) of magnetic resonance imaging at 7T to develop a quantitative, non-invasive, 3D-ultrahigh-resolution dGEMRIC MRI exam for femoral-tibial observations and T1 quantification of matrix changes in rabbits.

Takayuki Sakai^1,2, Masami Yoneyama³, Atsuya Watanabe^4,5, Daichi Murayama¹, Shigehiro Ochi¹, and Tosiaki Miyati^6
1Radiology, Eastern Chiba Medical Center, Tonage, Japan, ²Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan, ³Philips Japan, Tokyo, Japan, ⁴General Medical Services, Chiba University Graduate School of Medicine, Chiba, Japan, ⁵Orthopaedic Surgery, Eastern Chiba Medical Center, Chiba, Japan, ⁶Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan

Cartilage degeneration can be evaluated non-invasively by qualitative T2 mapping MRI. Although cartilage evaluation using T2 mapping is desirable in cases which open reduction and internal fixation for fractures around the knee joint and osteotomy for knee osteoarthritis, evaluation is often difficult due to the existence of metal artifacts. Theoretically, metal artifacts are suppressed by metal artifact reduction techniques such as VAT and SEMAC. Therefore, we evaluated the usefulness of T2 mapping using VAT or SEMAC for cartilage around the knee joint that was metal-fixed after surgery.

Yu Shun¹, Lin Min-gui¹, Zhongshuai Zhang², Chen Xian-yuan¹, and Ma Mingping^1
1Radiology department, Fujian Provincial Hospital, fuzhou, China, ²Diagnostic Imaging, SIEMENS Healthcare, Shanghai, China

This study aimed to evaluate the feasibility of using MRI to monitor the efficacy of tumor necrosis factor-α antagonists in the treatment of SpA (axial spondyloarthritis).