Tobit Führes¹, Andreas Julian Riexinger¹, Jan Martin², Martin Gerhard Loh¹, Bernhard Hensel³, Michael Uder¹, and Frederik Bernd Laun^1
1University Hospital Erlangen, Erlangen, Germany, ²Lund University, Lund, Sweden, ³Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany

In this study, we acquired diffusion-weighted image data of 15 healthy volunteers at four different TE. A ROI-based IVIM analysis showed that the pseudodiffusion coefficients did not change with TE, whereas the perfusion fractions rose significantly for bi- and triexponential IVIM curves at longer TE. A quantitative analysis indicates that the triexponential perfusion fractions are unlikely attributable to venous and arterial blood compartments. Our results indicate moreover that the pseudodiffusion coefficients can be compared without TE-correction among studies performed with different TE.

Yuxin Zhang^1,2, Arnaud Guidon³, Xiaoili Zhao⁴, Gaohong Wu⁴, Hua Li⁴, Ruiqi Geng^1,2, and Diego Hernando^1,2
1Medical Physics, University of Wisconsin Madison, Madison, WI, United States, ²Radiology, University of Wisconsin Madison, Madison, WI, United States, ³GE Healthcare, Boston, MA, United States, ⁴GE Healthcare, Waukesha, WI, United States

Diffusion MRI of the liver has important applications in the detection of metastatic lesions. Unfortunately, conventional diffusion MRI is highly sensitive to cardiac-induced motion in the left lobe, whereas recently developed motion-robust diffusion MRI methods lead to lower SNR. This work demonstrates the feasibility of combining motion-robust diffusion MRI with DL reconstruction for improved DWI of the liver, including high motion robustness and high SNR. In early-stage evaluation, the combined technique provides excellent motion robustness, quantitative reliability, and high SNR throughout the entire liver, and may have application in the detection and evaluation of metastatic liver lesions.

Ruofan Sheng¹, Yunfei Zhang², Mengsu Zeng¹, and Yongming Dai^2
1Zhongshan Hospital affiliated to Fudan University, Shanghai, China, ²Central Research Institute, United Imaging Healthcare, Shanghai, China

Recently, a novel non-Gaussian DWI model, known as the fractional order calculus (FROC) model, was developed for biomedical applications. Until now, hardly has the FROC-DWI been applied in the hepatic imaging Thus, this study aimed to evaluate the value of FROC diffusion model in staging liver fibrosis. According to our results, the FROC-DWI-derived parameters (D, β, and μ) were significantly correlated with fibrosis stages, contributing positively to non-invasive assessment of liver fibrosis. The combination of FROC-DWI and conventional mono-exponential DWI held great potential in noninvasively staging liver fibrosis, superior to serum fibrosis biomarkers including APRI and FIB-4.

Maike Bode¹, Shuo Zhang^1,2, Nils A. Krämer¹, Christiane K. Kuhl¹, and Alexandra Barabasch^1
1Diagnostic and Interventional Radiology, University Hospital RWTH Aachen, Aachen, Germany, ²Philips Healthcare, Hamburg, Germany

Compressed sensing (CS) has been reported to accelerate acquisition time in morphological imaging without image quality loss. The impact of CS on diffusion weighted imaging (DWI) in liver MRI has not yet been investigated. Therefore, the aim of our study was to test whether CS-based reconstruction is useful in echo-planar imaging (EPI) DWI. In this intra-individual comparison, EPI-DWI with CS-based reconstruction (CS-DWI) received comparable image quality ratings as conventional EPI-DWI. However, in a direct head-to-head-comparison, we found that a small fraction of focal liver lesions was missed on CS-DWI without apparent reason.

Zheng Ye¹, Bin Song¹, Yuming Li¹, Qing Li², Lisha Nie³, and Xiaocheng Wei^3
1West China Hospital, Sichuan University, Chengdu, China, ²MR collaborations, Siemens Healthcare Ltd., Shanghai, China, ³MR Research, GE Healthcare, Beijing, China

Diffusion-weighted imaging (DWI) provides anatomic and functional information, and apparent diffusion coefficient (ADC) has been proposed as a valuable biomarker in liver diseases. Simultaneous multi-slice (SMS) technique allows for exciting and acquiring multiple slices at the same time, and thus reducing scan time, which has been recently proved to be feasible in liver imaging. Our study investigated the reproducibility and variability of liver ADC of SMS-DWI with different breathing schemes and different vendors. We found good reproducibility of liver ADC across different MR vendors in both breath-hold and free-breathing manner. However, liver ADC is less reproducible between different breathing schemes.

Jiqing Huang¹, Benjamin Leporq¹, BEUF Olivier¹, and Hélène Ratiney^1
1Univ Lyon, INSA Lyon, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69621, Lyon, Villeurbanne, France

 To determine an optimal b-values sampling scheme for different non-Gaussian diffusion models in the liver, including diffusion kurtosis imaging (DKI), stretched-exponential model (SEM), intravoxel incoherent motion (IVIM), we optimized diffusion-weighting b-values sets using simulations mimicking real data and a b-value selection based on a Monte Carlo-like approach. Estimation performances were evaluated in terms of mean square error on signal and mean absolute percentage error on parameters in simulated data. The parameter estimation, with optimized set of b-values was finally applied on real data. The results showed that comparable fitting parameters and reconstructing signal can be obtained with fractional b-values.

Qiying Ke¹, Tianyuan Zhang², Xuan Jin¹, Xinming Li¹, Yingjie Mei³, and Xianyue Quan^1
1Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, China, ²Department of Radiology, Foshan First People's Hospital, Foshan, China, ³Philips Healthcare, Guangzhou, China

Diffusion kurtosis imaging (DKI) is a promising non-invasive method for evaluating the expression of Ki-67, a marker of cellular proliferation in HCC, which may contribute to predict recurrence and prognosis preoperatively. In this study, we evaluated the potential role of DKI in preoperative prediction of Ki-67 expression in HCC. The results show that increased MK and decreased ADC values are potential predictive biomarkers for of Ki-67 expression of in HCC.

Anh T. Van¹, Sean McTavish¹, Johannes M. Peeters², Kilian Weiss³, Marcus R. Makowski¹, Rickmer F. Braren¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany, ²Philips Healthcare, Best, Netherlands, ³Philips Healthcare, Hamburg, Germany

In single shot diffusion imaging of moving organs, undesired motion during diffusion encoding introduces rapid phase variations in the obtained images. When partial Fourier encoding is used to reduce SNR loss in short T2 tissues, the motion-induced rapid phase variation compromises the partial Fourier reconstruction, resulting in “worm-like” artifacts in the reconstructed images. This work shows that by applying phase correction before the partial Fourier reconstruction motion-induced artifacts can be mitigated, improving the quality of diffusion-weighted images in liver applications.

Jie Yuan¹, Fan Mo², Yongming Dai², Yuan Feng³, Suhao Qiu³, Songhua Zhan¹, and Zhigang Gong^1
1Department of Radiology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, 201203, Shanghai, China, ²MR Collaboration, United Imaging Healthcare, Shanghai, China, ³Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China

Due to the non-invasive superiority, Magnetic Resonance Elastography (MRE) has emerged as an alternative approach to liver biopsy, the current golden standard for staging liver fibrosis. However, the use of external vibration devices brings costs of scan time and money. Diffusion Weighted Imaging (DWI) has shown the potential to characterize liver fibrosis at a microscopic level recently. The purpose of this study is to evaluate the potential of DWI to provide quantitative estimates of tissue stiffness without external devices among patients with different types of liver fibrosis and compare the inter-method agreement between MRE and the proposed method.

Hu Guo¹, Huiting Zhang², Junjiao Hu¹, and Jun Liu^1
1Department of Radiology, the Second Xiangya Hospital of Central South University, Changsha, China, ²MR Scientific Marketing, Siemens Healthcare, Wuhan, China

 The purpose of this study is to compare image quality and apparent diffusion coefficient (ADC) value between single-shot spin-echo echo-planar imaging (SS-EPI) and integrated slice-specific dynamic shimming (iShim) DWI methods in liver. Compared to SS-EPI, iShim had better image quality and showed more small lesions. No significant differences of ADC values were found between the two methods.

Sean McTavish¹, Anh T. Van¹, Johannes M. Peeters², Kilian Weiss³, Marcus R. Makowski¹, Rickmer F. Braren¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany, ²Philips Healthcare, Best, Netherlands, ³Philips Healthcare, Hamburg, Germany

Despite its strong clinical significance in lesion detection and tumor staging, liver DWI remains challenged by its strong sensitivity to motion effects. Motion-compensated diffusion encoding schemes have been recently proposed to improve DW liver signal homogeneity especially in the left liver lobe, a region typically affected by cardiac motion. In addition, a simplified gradient non-linearity correction scheme has been proposed for usage with standard pulsed gradient spin echo (pgse) diffusion encoding waveforms. The present work investigates the usage of this gradient nonlinearity correction algorithm with different motion compensated diffusion encoding gradient waveforms in the context of coronal ADC mapping in the liver.

Kosuke Morita¹, Masami Yoneyama², Hiroshi Hamano², Takeshi Nakaura³, Seitaro Oda³, Akira Sasao³, Hiroyuki Uetani³, Shogo Fukuda³, Masahiro Hatemura³, and Toshinori Hirai^3
1Radiology, Kumamoto university, kumamoto-shi, Japan, ²Philips Japan, shinagawa, Japan, ³Kumamoto university, kumamoto-shi, Japan

We used respiratory triggered MultiBand SENSE (MB-SENSE) DWI using variable-rate selective excitation (MB-VERSE). We first measured ADC values of liver and kidney and subsequently performed visual assessment. The MB-VERSE DWI reduced the imaging time while improving the image quality and robustness of ADC values.

Wen Huiquan¹, Zhang Yao², Lin Wusheng², Pi Shan², Fang Ling³, and Wang Jin^2
1Radiology, the Third Affiliated Hospital of Sun Yat-sen University (SYSU), Guangzhou, China, ²the Third Affiliated Hospital of Sun Yat-sen University (SYSU), Guangzhou, China, ³Department of Radiology, the Third Affiliated Hospital of Sun Yat-sen University (SYSU), Guangzhou, China

DWI is instrumental to screening and differential diagnosis of liver lesions. However, the diagnostic value DWI is often hindered by low SNR and severe image distortions, particularly in the left liver lobe. We explored the feasibility and efficacy of the combined use of AIR coil and multiplexed sensitivity encoding DWI (MUSE-DWI) in improving the image quality of liver. The results showed that MUSE-DWI with AIR Coil can effectively improve the image quality and reduce the image distortion of liver images, compared with the traditional abdomen coil, thus it is a feasible and effective method for detection of liver lesions.

Meryem Khalfallah¹, Gwenaël Pagé¹, Sabrina Doblas¹, Bernard Van-Beers^1,2, and Philippe Garteiser^1
1Center of research on inflammation (UMR1149), Inserm - Université de Paris, Paris, France, ²Beaujon hospital radiology departement, APHP, Paris, France

Temporal diffusion spectroscopy using oscillating encoding gradients enables assessing tissue microstructure at a user-selected, arbitrary spatial scale. It has been demonstrated that this method is feasible with OGSE-EPI sequence. To study its robustness an OGSE-EPI sequence was implemented and repeatability and signal to noise ratio were assessed with two radiofrequency hardware setups and with or without respiratory gating. The effect of OGSE frequency was assessed for the pure diffusion coefficient (D) and for the apparent diffusion coefficient (ADC). Using a 4-channel surface coil and respiratory gating when measuring ADC at 100 Hz, the optimal repeatability coefficient (28%) was obtained.

Pin Yang¹, YanLi Jiang¹, PengFei Wang¹, TieJun Gan¹, Rui Wang¹, Jing Zhang¹, and Kai Ai^2
1Department of Magnetic Resonance, LanZhou University Second Hospital, Lanzhou, China, ²Philips Healthcare, Xi’an, China

The correlation between T1 relaxation times of hepatobiliary phase (T1_HBP) and indocyanine green retention at 15min (ICG R15), as well as transient elastrography (TE) still need to be confirmed. This study evaluates the correlation among T1_HBP, ICG R15 and TE. Our research showed that T1_HBP had significant correlation with ICG R15 and TE. The above results demonstrated that T1_HBP may be a promising radiography biomarker for liver function assessment.

Qian Wan^1,2, Hao Peng ¹, Jianxun Lyu^1,2, Xiaoyi Liu³, Chuanli Cheng¹, Feng Liu³, Yangzi Qiao¹, Hairong Zheng¹, Xin Liu¹, Yi Wang³, and Chao Zou^1
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²Shenzhen College of Advanced Technology,University of Chinese Academy of Sciences, Shenzhen, China, ³Peking University People's Hospital, Beijing, China

The severity of live fibrosis is one of the most important prognostic factors for the long-term outcomes of Nonalcoholic steatohepatitis (NASH). Early and precise diagnosis is of crucial importance for the disease management of NASH patients. In this work, we detected the liver fibrosis using water specific T1 mapping with Gadoxetic Acid -enhanced MRI in a rat NASH model induced by methionine-choline deficient (MCD) diet. The study revealed that the reduction rates of water-T1 relaxation time before and after Gd-EOB-DTPA administration might be a useful tool to stage the mild and moderate live fibrosis in rat NASH model. 

Verena C. Obmann¹, Damiano Catucci¹, Annalisa Berzigotti², Christoph Gräni³, Lukas Ebner¹, Johannes Thomas Heverhagen¹, Andreas Christe¹, and Adrian Thomas Huber^1
1Radiology, Inselspital, University of Bern, Bern, Switzerland, ²Visceral Surgery and Medicine, University of Bern, Inselspital, Bern, Switzerland, ³Cardiology, University of Bern, Inselspital, Bern, Switzerland

This study demonstrates that the MRI T1 reduction rate, based on T1 mapping before and after GD-EOB-DTPA, allows an accurate analysis of liver function and may be used interchangeably at 1.5T and 3T without image post-processing. T1 reduction rate was able to distinguish patients with no liver disease, patients with CLD and patients with liver cirrhosis Child A-C from one another.

Xueqin ZHANG¹, Jian LU¹, Jifeng JIANG¹, and Weibo CHEN^2
1the Third People’s Hospital of Nantong, Nantong, China, ²Philips Healthcare, Shanghai, China

The purpose of this study was to assess the ability of hepatocyte fraction on Gd-EOB-DTPA-enhanced MRI for the quantitative evaluation of liver function. We used Look-Locker sequences to acquire T1 mapping images pre and post-contrast at 20 minutes after Gd-EOB-DTPA administration. T1 relaxation times (T1pre and T1post) of the liver, reduction rates of T1 relaxation times (rrT1), hepatocyte fraction (HeF) and K_Hep were measured. Our study showed that T1post, rrT1, HeF and K_Hep vlaues based on Gd-EOB-DTPA-enhanced T1 mapping MRI are efficient diagnostic tools for the quantitative evaluation of liver function.

Zuhui Zhu¹, Wei Xing¹, Haifeng Liu¹, Qing Wang¹, Yanan Du¹, Yufeng Li¹, and Jilei Zhang^2
1Department of Radiology, third Affiliated Hospital of Soochow University & Changzhou First People's Hospital, Changzhou, China, ²Philips Healthcare, Shanghai, China

To explore parameters obtained by Gd-EOB-DTPA T1 mapping and extracellular volume fraction in evaluating hepatic fibrosis (HF) in a rabbit model. The HF model was established by carbon tetrachloride (CCl4).Rabbits underwent pathological examination to determine the HF stage using the metavir classification system. Parameters including T1native, T110 min, T120 min, ECV10 min and ECV20 min were measured and compared among the different HF stages using spearman correlation coefficients and receiver operating characteristic curve. The AUC of T120 min was higher than that of other quantitative parameters. T1 mapping parameters and ECV fraction are closely associated with HF progression.

Christian Simonsson^1,2, Markus Karlsson¹, Nils Dahlström¹, Peter Lundberg^1,2, Wolf Claus Bartholomä^1,2, Gunnar Cedersund^2,3, Per Sandström⁴, and Anna Lindhoff Larsson3^4
1Department of Radiation Physics, Radiology, Linköping University, Linköping, Sweden, ²Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden, ³Department of Medical Engineering, Linköping University, Linköping, Sweden, ⁴3Department of Surgery, Department of biomedical and clinical sciences, Linköping University, Linköping, Sweden

A range of severe liver diseases are identified only in very late stages. At a late stage, the only remaining treatment may be resective liver surgery. The resection can lead to serious complications if the remnant tissue fails to match the requirement of liver function. Therefore, it is valuable to accurately measure both regional and global liver function to better predict the outcome of the surgery. Here we use DCE-MRI to show that there are differences in Gadoxetate uptake both between patients and regional difference between the adjacent segments before and after resective surgery.