ELECTRONIC POSTER - ismrm

Thursday 13:30-15:30 Computer 100
13:30 4706. Optimization of the B-Sampling for Bi-Exponential Analysis of Diffusion-Weighted
Imaging
Jeff Lei Zhang 1 , Eric E. Sigmund 1 , Hersh Chandarana 1 , Henry Rusinek 1 , Hua Guo 1 ,
Pippa Storey 1 , Qun Chen 1 , Vivian S. Lee 1
1 Department of Radiology, New York University, New York, NY, United States
Synopsis: To improve precision of bi-exponential parameters of diffusion weighted imaging (DWI), we proposed a method for
optimizing b values for DWI acquisition. Monte Carlo simulation was performed to explore whether the optimized b values would
improve the bi-exponential parameters’ ability in differentiating benign and malignant renal lesions. Results showed that, using the
optimized b values, the differentiability of perfusion fraction for the two types of lesions improved by 22%±7%, compared with
uniformly distributed b values. The method should be applicable to DWI of any other tissues or organs where bi-exponential analysis
is used.
14:00 4707. Signal to Noise Ratio of High B-Value Diffusion Weighted Images Is Improved
Using Computed Diffusion Weighted Imaging
Matthew David Blackledge 1 , David J. Collins 1 , Dow-Mu Koh 1 , Martin O. Leach 1
1 CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton,
Surrey, United Kingdom
AAn acquisition scheme optimized for computed Diffusion Weighted Imaging (cDWI) is discussed and a theoretical model for
diffusion weighted image noise is presented. It is demonstrated through theory and experimental studies that noise is reduced in
calculated high b-value images compared to conventional acquired high b-value DWI using this method.
14:30 4708. Comparison of Liver ADC Measurements Using Breath-Hold, Free Breath-Hold
and Respiratory Gating Echoplanar Diffusion-Weighted Imaging Sequences Using Parallel
Imaging Technique with Different Acceleration Factors
Chun-Jung Juan 1 , Hing-Chiu Chang 2,3 , Hsiao-Wen Chung 1,3 , Chi-Hong Chu 4 , Cheng-
Chieh Cheng 1,3 , Su-Chin Chiu 1,3 , Hui-Chu Chiu 5,6 , Cheng-Hsien Hsu 7 , Cheng-Yu Chen 1 ,
Guo-Shu Huang 1
1 Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan; 2 Applied Science Laboratory, GE
Healthcare Taiwan, Taipei, Taiwan; 3 Institute of Biomedical Electronics and Bioinformatics, National Taiwan
University, Taipei, Taiwan; 4 Section of General Surgery, Department of Surgery, Tri-Service General Hospital,
Taipei, Taiwan; 5 Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan; 6 EMBA in
Global Chinese Management, Department of Business Administration, College of Management, Tamkang
University, Taiwan; 7 Division of Software Design, Notebook Unit 5, Quanta Computer Inc., Taiwan
Inter-experimental comparison of the liver apparent diffusion coefficient (ADC) value remains challenging. In this study the effect of
repetition time (TR) and acceleration factors on the liver ADC measurement is examined. Our study shows that free-breath method
allows ADC measurement consistent with breath-hold method with the TR. The ADC values measured at a longer TR in both freebreath
and respiration-triggered methods are significantly higher than breath-hold method. Our results also depict significant
differences in liver ADC values when different acceleration factors are chosen. Our results highlight the important of TR and
acceleration factors in liver ADC measurements for inter-experimental comparison.
15:00 4709. Assessment of Variability of Region of Interest (ROI) Delineation on Diffusion
Weighted MRI (DW-MRI) Using Manual and Semi-Automated Computer Methods
Nina Tunariu 1 , James A. d'Arcy, Veronica A. Morgan 1 , Michael Germuska, Catherine G.
Simpkin, Sharon L. Giles 2 , David J. Collins, Nandita M. deSouza
1 CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital,
Sutton, Surrey, United Kingdom; 2 CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research
and Royal Marsden Hospital, United Kingdom
A major challenge for implementing diffusion-weighted magnetic resonance imaging (DW-MRI) as tumour response biomarker in
multicentre clinical trials is in measuring changes in individual patients reliably and reproducibly. The delineation of the region of
interest (ROI) has a great impact on final reproducibility. This study compares ADC values obtained using in-house computer ROI
drawing software (Diffusion View) to segment tumour with those obtained from a manual drawing technique. Computer generated
ROIs have the advantage of less variability, operator independence and significant time saving and support the feasibility of use of
automated DWI measurements in clinical trials.