Matthew D Blackledge¹, Dow-Mu Koh¹, Anwar R Padhani², James J Stirling², N J Taylor², David J Collins¹, and Martin O Leach^1
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.

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 Nievelstein^1
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.

Jin Cheng¹, Yi Wang¹, Jie Deng², Robert J McCarthy³, Gongwei Wang⁴, Yingjiang Ye⁵, He Wang⁶, and Xiangke Du^1
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.

Ek T Tan¹, Luca Marinelli¹, Zachary W Slavens², Christopher J Hardy¹, and Kevin F King^2
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.

Moti Freiman¹, Jeannette M Perez-Rossello¹, Michael J Callahan¹, Mark Bittman¹, Stephan D Voss¹, Robert V Mulkern¹, and Simon K Warfield^1
1Radiology, Children's Hospital Boston/Harvard Medical School, Boston, MA, United States

 

Shintaro Ichikawa¹, Utaroh Motosugi¹, Tomoaki Ichikawa¹, Hiroyuki Morisaka¹, Katsuhiro Sano¹, Tetsuya Wakayama², and Tsutomu Araki^1
1University of Yamanashi, Chuo, Yamanashi, Japan, ²Advanced Application Center, GE Healthecare Japan

 

Hing-Chiu Chang^1,2, Nan-Kuei Chen³, Chun-Jung Juan⁴, Tzu-Chao Chuang⁵, Cheng-Wen Ko⁶, and Hsiao-Wen Chung^2,4
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.

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 Taouli^1
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.

Darwin S. Gao^1,2, Zhongwei Qiao^1,2, Matthew M. Cheung^1,2, April M. Chow^1,2, Shujuan Fan^1,2, Kwan Man³, and Ed X. Wu^1,2
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.

He Wang¹, Yingshi Sun², Yong Zhang¹, and Guang Cao^1
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.