Computed Diffusion-Weighted Image in the Abdomen

Transcription

1 Computed Diffusion-Weighted Image in the Abdomen Poster No.: C-0234 Congress: ECR 2014 Type: Scientific Exhibit Authors: T. Yoshikawa 1, N. Aoyama 1, Y. Ohno 1, K. Kyotani 1, Y. Kassai 2, K. Sofue 1, M. Nishio 1, H. Koyama 1, K. Sugimura 1 ; 1 Kobe/JP, 2 Otawara, Tochigi/JP Keywords: DOI: Abdomen, Biliary Tract / Gallbladder, Liver, MR-Diffusion/ Perfusion, Image manipulation / Reconstruction, Computer Applications-Detection, diagnosis, Technology assessment, Cancer, Image verification, Tissue characterisation /ecr2014/C-0234 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 10

2 Aims and objectives In current abdominal MRI, diffusion-weighted imaging (DWI) is one of the most important techniques and routinely used worldwide. However, problems still remain such as contamination of perfusion effect at lower b values, low signal-to-noise ratio at higher b values, inadequate signal suppression of fluid, and image distortions due to respiration or intestinal air. In general, estimation of optimal b value prior to examination is difficult. Interpretation of apparent diffusion coefficient (ADC) map needs expertise for MRI. Recently, computed DWI (cdwi) software has been developed and reportedly useful in body and pelvic DWI. This software allows image observers to reconstruct DW images at any b value as a post-processing after MR examination finishes. However, to date, we have only one report on application of this new technique for detection of liver metastasis with fixed b value. The purpose of this study was to assess capability of cdwi in evaluation of various abdominal diseases. Methods and materials Thirty-four patients (male: 16, female: 18, mean: 69.0 years) who had focal lesions in the liver, bile duct (BD), or pancreas were retrospectively analyzed. All of whom underwent MRI at a 3T scanner (Vantage Titan 3T; Toshiba Medical Systems, Otawara, Japan). Actual DWIs were obtained with SE-EPI sequence (TR/TE/FA= /70/90, b values: 0, 1000, matrix: , thk: 4-7 mm, slice, Nex: 4, scan time: 4-6 min, PASTA+SPAIR, PI: 2.2 (y), MPG: y, z) as one of routine sequences in our institution. cdwi images at low (500) and high (2000) b values were calculated and reconstructed to DICOM-formatted images using a personal computer and prototype software (Toshiba Medical Systems) (fig.1). Two patients had HCCs, 1 CCC, 1 bile duct cancer, 1 gallbladder cancer, 8 pancreatic cancers, 3 metastatic liver cancer, 1 metastatic pancreatic cancer, 3 node metastases, and 2 peritoneal disseminations. These lesions were assigned as malignant lesions. Three patients had hepatic hemangiomas, 3 bilomas, 1 hemorrhagic hepatic cyst, 3 IPMNs, and 3 pancreatic SCNs. These were assigned as cystic lesions. One had post- RFA lesion,1 cholangitis, and 4 pancreatitis. These were assigned as inflammatory lesions. Page 2 of 10

3 Image quality for cdwis (b=500) were assessed using a 5-point scale and compared to that of actual DWI (b=1000). One radiologist assessed conspicuity of lesions and signal suppression of benign lesions or areas on cdwi (b=2000) using 5-point scales and compared with those of actual DWI (b=1000). Images for this section: Fig. 1 Page 3 of 10

4 Results Image quality was significantly improved on cdwi (b=500) than on actual DWI (p<0.0001). Water signal in the gallbladder (p<0.0001) and cystic lesions (hepatic cysts (p=0.007), renal cyst (p=0.004)) were significantly reduced on cdwi (b=2000) than on actual DWI. Conspicuity of malignant lesions was significantly higher on cdwi (b=2000) than on actual DWI (p=0.02). Conspicuities of cystic (p=0.004) and inflammatory (p=0.02) lesions were significantly lower on cdwi (b=2000) than on actual DWI. Signal suppression in the necrotic part of metastatic tumors was more clearly seen on cdwi (b=2000) than on actual DWI in 3 cases. Representative cases are shown on figs 2-5. Images for this section: Page 4 of 10

5 Fig. 2 Page 5 of 10

6 Fig. 3 Page 6 of 10

7 Fig. 4 Page 7 of 10

8 Fig. 5 Page 8 of 10

9 Conclusion DISCUSSION cdwi software enables reconstruction of DW image with any b value after MR examinations with short time even on personal computers. It has the potentials to improve image quality when calculated at lower b values and to add useful information for diagnosis at higher b values. However, it should be noticed that perfusion effect cannot be eliminated when actual DW images are acquired at low b values. CONCLUSION cdwi has the potentials to improve image quality when calculated at lower b values and to add useful information for diagnosis at higher b values. Personal information References DWIBS Liver Prostate Koh DM, Blackledge M, Padhani AR, Takahara T, Kwee TC, Leach MO, Collins DJ. Whole-body diffusion-weighted MRI: tips, tricks, and pitfalls. AJR Am J Roentgenol. 2012;199(2): Blackledge MD, Leach MO, Collins DJ, Koh DM. Computed diffusionweighted MR imaging may improve tumor detection. Radiology Nov;261(2): Shimizu H, Isoda H, Fujimoto K, Kawahara S, Furuta A, Shibata T, Togashi K. 4. Comparison of acquired diffusion weighted imaging and computed diffusion weighted imaging for detection of hepatic metastases. Eur J Radiol. 2013;82(3): Page 9 of 10

10 Maas MC, Fütterer JJ, Scheenen TW. Quantitative Evaluation of Computed High b Value Diffusion-Weighted Magnetic Resonance Imaging of the Prostate. Invest Radiol. 2013;48(11): Ueno Y, Takahashi S, Kitajima K, Kimura T, Aoki I, Kawakami F, Miyake H, Ohno Y, Sugimura K. Computed diffusion-weighted imaging using 3- T magnetic resonance imaging for prostate cancer diagnosis. Eur Radiol. 2013;23(12): Rosenkrantz AB, Chandarana H, Hindman N, Deng FM, Babb JS, Taneja SS, Geppert C. Computed diffusion-weighted imaging of the prostate at 3 T: impact on image quality and tumour detection. Eur Radiol. 2013;23(11): Page 10 of 10