Body Diffusion
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Tuesday 8 May 2012
Room 202  13:30 - 15:30 Moderators: David J. Collins, Bachir Taouli

13:30 0255.   The feasibility of evaluating treatment response of bone metastases by segmenting tumor diffusion volumes to estimate total disease burden on whole body diffusion-weighted imaging
Matthew D Blackledge1, Dow-Mu Koh1, Anwar R Padhani2, James J Stirling2, N J Taylor2, David J Collins1, and Martin O Leach1
1CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton, United Kingdom, 2Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Northwood, London, United Kingdom

There is currently no standard for evaluating response of bone metastases to novel therapeutics, greatly inhibiting pharmaceutical development. In this feasibility study we investigate the role of tumour burden estimates and apparent diffusion coefficients measured using whole body diffusion weighted imaging (WBDWI) for monitoring treatment response. Good correlations are found between final clinical outcome in patients diagnosed with bone metastases and changes in median ADC value and tumour burden, as predicted using semi-automatic segmentation methods. It is concluded that such measurements from WBDWI will provide a useful tool in future clinical trials.

13:42 0256.   
Whole-body MRI, including diffusion-weighted imaging, for staging lymphoma: comparison to CT in 101 patients
Thomas Kwee1, Malou Vermoolen1, Erik Akkerman2, Marie José Kersten3, Rob Fijnheer4, Inge Ludwig5, Frederik Beek1, Maarten van Leeuwen1, Marc Bierings6, Joseph Zsiros7, Henriëtte Quarles van Ufford1, Jaap Stoker2, Willem Mali1, and Rutger-Jan Nievelstein1
1Radiology, UMC Utrecht, Utrecht, Netherlands, 2Radiology, AMC Amsterdam, Amsterdam, Netherlands, 3Hematology, AMC Amsterdam, Amsterdam, Netherlands, 4Hematology, Meander MC, Amersfoort, Netherlands, 5Hematology, UMC Utrecht, Utrecht, Netherlands, 6Pediatric Hematology, UMC Utrecht, Utrecht, Netherlands, 7Pediatric Hematology, AMC Amsterdam, Amsterdam, Netherlands

Whole-body MRI may be an alternative to CT for staging lymphoma. Furthermore, the use of diffusion-weighted imaging (DWI) may facilitate staging because of its high lesion-to-background contrast. In this prospective multicenter study including 101 consecutive patients with newly diagnosed lymphoma, staging of newly diagnosed lymphoma using whole-body MRI (without and with DWI) equalled staging using CT in the majority of patients. Disagreements between whole-body MRI and CT were mostly caused by overstaging of the former relative to the latter, with the number of correctly and incorrectly overstaged cases being approximately equal. The potential advantage of DWI is still unproven.

13:54 0257.   Predict Metastatic and Benign Lymph Nodes in Patients with Gastric Carcinoma by Using Diffusion-Weighted Imaging
Jin Cheng1, Yi Wang1, Jie Deng2, Robert J McCarthy3, Gongwei Wang4, Yingjiang Ye5, He Wang6, and Xiangke Du1
1Department of Radiology, Peking University People's Hospital, Beijing, Beijing, China, 2Department of Radiology, Children's Memorial Hospital, Chicago, Illinois, United States, 3Department of Anesthesiology, Northwestern University, Chicago, Illinois, United States, 4Department of Pathology, Peking University People's Hospital, Beijing, Beijing, China, 5Department of Gastrointestinal Surgery, Peking University People's Hospital, Beijing, Beijing, China, 6GE Health Care

We prospectively proposed to assess the predictive capability of DWI in determing metastatic and benign lymph nodes in patients with gastric carcinoma. The median ADC value of metastatic nodes was lower than that of the benign nodes and a statistical difference was seen. DWI represented as ADC values shows more accurately diagnostic performance in predicting nodal metastases in gastric carcinoma than dose conventional MRI. Furthermore, DWI combined with conventional MRI had the greatest predictive power compared to DWI or anatomic MRI alone, which can provide a great help in determining appropriate therapeutic strateges.

14:06 0258.   
Effects of gradient nonlinearity, its correction methods and distortion on diffusion weighted imaging
Ek T Tan1, Luca Marinelli1, Zachary W Slavens2, Christopher J Hardy1, and Kevin F King2
1GE Global Research, Niskayuna, NY, United States, 2GE Healthcare, Waukesha, WI, United States

The apparent diffusion coefficient (ADC) obtained with diffusion weighted imaging (DWI) is a promising non-contrast cancer imaging bio-marker. Gradient nonlinearity (GN) results in spatially-varying ADC, an effect that is confounded by distortion related to the DWI acquisition. Evaluations were performed in two whole-body MRI systems at 1.5T in various anatomical regions. GN correction (GNC) used up to 13 orders of spherical harmonics, and was used with and without the full b-matrix in the diffusion-tensor computation. GNC resulted in a significant reduction in ADC error in both systems. Distortion effects resulted in a significant ADC difference between both systems.

14:18 0259.   In-vivo reliability assessment of Intravoxel incoherent motion diffusion weighted MRI parameters
Moti Freiman1, Jeannette M Perez-Rossello1, Michael J Callahan1, Mark Bittman1, Stephan D Voss1, Robert V Mulkern1, and Simon K Warfield1
1Radiology, Children's Hospital Boston/Harvard Medical School, Boston, MA, United States


14:30 0260.   Intravoxel incoherent motion imaging of the liver: Which affects more on apparent diffusion coefficient changes of cirrhosis and liver lesions, D or D*?
Shintaro Ichikawa1, Utaroh Motosugi1, Tomoaki Ichikawa1, Hiroyuki Morisaka1, Katsuhiro Sano1, Tetsuya Wakayama2, and Tsutomu Araki1
1University of Yamanashi, Chuo, Yamanashi, Japan, 2Advanced Application Center, GE Healthecare Japan


14:42 0261.   Free breathing Liver DWI using PROPELLER-DW-EPI with inherent reductions of geometric distortion and motion artifacts at 1.5T
Hing-Chiu Chang1,2, Nan-Kuei Chen3, Chun-Jung Juan4, Tzu-Chao Chuang5, Cheng-Wen Ko6, and Hsiao-Wen Chung2,4
1Global Applied Science Laboratory, GE Healthcare, Taipei, Taiwan, 2Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 3Brain Imaging and Analysis Center, Duke University, North Carolina, United States, 4Department of Radiology, Tri-Service General Hospital, Taiwan, 5Electrical Engineering, National Sun Yat-sen University, Taiwan, 6Department of Computer Science and Engineering, National Sun Yat-Sen University, Taiwan

Quantitative ADC measurement in liver has been shown to facilitate differential diagnosis of simple versus hydatid cyst. The consequent changes in repetition time of respiratory gating DW-EPI may lead to bias in ADC quantification, especially for long T1 hepatic cyst. The aim of this study is to demonstrate a free breathing ADC measurement method using PROPELLER-DW-EPI. The removal of oblique N/2 ghost prior to PROPELLER reconstruction was accomplished using reference-based and the other reference-free (2D phase-cycled reconstruction) methods, with their results compared. Our preliminary result demonstrates that free breathing PROPELLER-DW-EPI is an attractive alternative for precise ADC measurements in liver.

14:54 0262.   Intravoxel incoherent motion diffusion-weighted imaging for detection of liver fibrosis in HCV: comparison of four sequences
Hadrien Arezki Dyvorne1, Thomas Nevers1, Nicola Galea2, M. Isabel Fiel3, David Carpenter1, Edmund Wong1, Matthew Orton4, Andre de Oliveira5, Marie-Louise Vachon3, Manjil Chatterji1, Douglas Dieterich3, and Bachir Taouli1
1Radiology, Mount Sinai School of Medicine, New York, New York, United States, 2Sapienza University, Rome, Italy, 3Department of Medicine/Liver Disease, Mount Sinai School of Medicine, New York, New York, United States, 4CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton, Surrey, United Kingdom, 5AG Healthcare Sector, Siemens, Erlangen, Germany

This study compares the performance and reproducibility of four diffusion-weighted sequences using multiple b values and biexponential fit for the detection of liver fibrosis in chronic hepatitis C. We investigated the role of gradient polarity and respiratory monitoring on the reproducibility and diagnostic quality of IVIM parameters. For all sequences, results showed acceptable to excellent reproducibility and a marked decrease of diffusion, perfusion fraction and apparent diffusion coefficients with the degree of fibrosis. In addition, free breathing acquisitions were found to give the better results.

15:06 0263.   Effect of Diffusion Time on Liver DWI
Darwin S. Gao1,2, Zhongwei Qiao1,2, Matthew M. Cheung1,2, April M. Chow1,2, Shujuan Fan1,2, Kwan Man3, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, 3Department of Surgery, The University of Hong Kong, Hong Kong SAR, China

In liver, diffusion decay can depend on not only b-value but also the diffusion time (∆) because water molecule diffusion is hindered and restricted by cellular microstructures, such as cell membrane, cytoskeleton, and macromolecules in tissue environment. In this study, we aimed to investigate the dependence of various diffusion measurements on diffusion time ∆ by acquiring and analyzing DW signal with various b-values at different diffusion times (∆s) in normal rat liver in vivo. Restricted diffusion behavior was observed in liver in vivo, demonstrating the effect of both b-value and ∆ on liver DWI quantification.

15:18 0264.   Diffusion behavior in rectal cancer: comparison of mono-exponential, bi-exponential and continuously distributed exponential models
He Wang1, Yingshi Sun2, Yong Zhang1, and Guang Cao1
1Applied Science Lab, GE Healthcare, Shanghai, China, 2Department of Radiology, Peking University Cancer Hospital, Beijing, China

We compared three diffusion models to evaluate rectal cancer, which include mono-exponential, bi-mono-exponential and continuously distributed exponential model. We found the continuously distributed exponential model has an extremely small value of chi-square in fitting the rectal cancer diffusion data which means this model may reveal the ‘true’ distribution of diffusion components in rectal cancer.