Have an account? Please log in.
Text size: Small font Default font Larger font
.
Radiology Daily
Radiology Daily PracticalReviews.com Radiology Daily

Diffusion-Weighted MR Imaging Helpful the Differential Diagnosis of Pancreatic Cystic Lesions

July 6, 2009
Written by: , Filed in: Gastrointestinal Imaging
  • Comments
.

A recent study was conducted to determine if diffusion-weighted MR imaging may be of value in the characterization and differential diagnosis of pancreatic cystic lesions.

Design
Prospective analysis.

Participants

39 consecutive patients with 42 pancreatic cystic lesions measuring ≥1.0 cm. The lesions included 16 simple cysts, 7 pseudocysts, 5 abscesses, 3 hydatid cysts, 2 serous cystadenomas, 3 mucinous cystadenomas, 2 mucinous cystadenocarcinomas, and 4 cystic degenerated adenocarcinomas.

Methodology
MR examinations were performed on a 1.5-Tesla system. Routine abdominal MR protocol was employed, which included unenhanced axial T1-weighted breath-hold spoiled gradient echo with and without fat saturation, coronal and axial T2-weighted single-shot turbo spin-echo images, and axial T2-weighted single-shot turbo spin-echo images with fat saturation.

Subsequently, axial single-shot spin-echo planar diffusion-weighted imaging (DWI) sequences were acquired with b values of 0 second/mm2, 500 seconds/mm2, and 1000 seconds/mm2. Subsequently, T1-weighted breath-hold fast-field echo dynamic images were obtained following intravenous gadolinium administration.

Lesion signal intensity on DWI was compared with the signal intensity of the pancreas. The lesions were categorized into two groups. Group 1 included simple cysts and pseudocysts, while group 2 consisted of the other benign and malignant lesions.

Review for Practicing Radiologists The University of California, San Francisco School of Medicine, Department of Radiology and Biomedical Imaging Review for Practicing Radiologists an intensive clinical radiologic review and self-assessment covering the following radiology subspecialties: Vascular-Interventional, Breast, Neuro, Gastrointestinal and Pulmonary Imaging. The program is designed for radiologists in clinical practice. Click here to read more or order: Review for Practicing Radiologists

Results
All of the cystic lesions were hyperintense on DWI with b values of 0 and 500 seconds/mm2 at visual inspection. However, with a b value 1000 seconds/mm2, the abscesses and hydatid and neoplastic cysts were hyperintense, while the simple cysts and pseudocysts were isointense.

Accordingly, the corresponding apparent diffusion coefficient values and ratios were significantly lower in this group. The cyst-to-pancreas signal intensity ratios of the abscesses and hydatid and neoplastic cysts were also significantly higher than those of the simple cysts and pseudocysts at this b value.

Sensitivity was 70% and specificity was 90% for differentiating abscesses, hydatid cysts, and neoplastic cysts from simple cysts and pseudocysts when using a cyst-to-pancreas signal intensity ratio cutoff value of 1.9.

Reviewer’s Comments
Diffusion-weighted MR imaging may be of value and added benefit in the differential diagnosis of cystic lesions of the pancreas.

The results of this study are useful in demonstrating the additional information that can be acquired with the use of DWI. In particular, this may be helpful when trying to distinguish simple cysts and pseudocysts from neoplastic cystic lesions.

One of the limitations reported in this study was that the echoplanar sequence used with a higher b value consequently had a lower signal-to-noise ratio, which resulted in greater image distortion. (

Author: John C. Sabatino, MD).

Reference:

Inan N, Arslan A, et al. Diffusion-Weighted Imaging in the Differential Diagnosis of Cystic Lesions of the Pancreas.AJR; 2008;191 (October): 1115-1121

Review for Practicing Radiologists The University of California, San Francisco School of Medicine, Department of Radiology and Biomedical Imaging Review for Practicing Radiologists an intensive clinical radiologic review and self-assessment covering the following radiology subspecialties: Vascular-Interventional, Breast, Neuro, Gastrointestinal and Pulmonary Imaging. The program is designed for radiologists in clinical practice. Click here to read more or order: Review for Practicing Radiologists
.
  • Comments
.

Would you like to keep current with radiological news and information?

Post Your Comments and Responses

Comments are closed.