Brief Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Oct 21, 2013; 19(39): 6651-6655
Published online Oct 21, 2013. doi: 10.3748/wjg.v19.i39.6651
Importance of b value in diffusion weighted imaging for the diagnosis of pancreatic cancer
Jin-Gang Hao, Jia-Ping Wang, Ya-Lv Gu, Ming-Liang Lu
Jin-Gang Hao, Jia-Ping Wang, Ya-Lv Gu, Department of Radiology, the Second Affiliated Hospital of Kunming Medical University, Kunming 650101, Yunnan Province, China
Ming-Liang Lu, Department of Gastroenterology, the Second Affiliated Hospital of Kunming Medical University, Kunming 650101, Yunnan Province, China
Author contributions: Lu ML designed the research and controlled the structure and quality of the paper; Hao JG proposed the study and collected and analyzed the data, and wrote the first draft; Wang JP and Gu YL enriched and improved the discussion section.
Correspondence to: Ming-Liang Lu, Attending Doctor, Department of Gastroenterology, the Second Affiliated Hospital of Kunming Medical University, Kunrui Road 112, Kunming 650101, Yunnan Province, China. lml19910@163.com
Telephone: +86-871-65351281 Fax: +86-871-65351281
Received: July 14, 2013
Revised: September 2, 2013
Accepted: September 16, 2013
Published online: October 21, 2013
Abstract

AIM: To investigate the use of multi-b-value diffusion-weighted imaging in diagnosing pancreatic cancer.

METHODS: We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the Second Affiliated Hospital of Kunming Medical University from December 2008 to January 2011. The demographic characteristics, clinical presentation, routine magnetic resonance imaging and diffusion weighted imaging (DWI) features with different b values were reviewed. Continuous data were expressed as mean ± SD. Comparisons between pancreatic cancer and benign pancreatic tumors were performed using the Student’s t test. A probability of P < 0.05 was considered statistically significant.

RESULTS: Thirty-three patients with pancreatic cancer were identified. The mean age at diagnosis was 60 ± 5.6 years. The male: female ratio was 21:12. Twenty cases were confirmed by surgical resection and 13 by biopsy of metastases. T1 weighted images demonstrated a pancreatic head mass in 16 patients, a pancreatic body mass in 10 cases, and a pancreatic tail mass with pancreatic atrophy in 7 cases. Eight patients had hepatic metastases, 13 had invasion or envelopment of mesenteric vessels, 4 had bone metastases, and 8 had lymph node metastases. DWI demonstrated an irregular intense mass with unclear margins. Necrotic tissue demonstrated an uneven low signal. A b of 1100 s/mm2 was associated with a high intensity signal with poor anatomical delineation. A b of 700 s/mm2 was associated with apparent diffusion coefficients (ADCs) that were useful in distinguishing benign and malignant pancreatic tumors (P < 0.05). b values of 50, 350, 400, 450 and 1100 s/mm2 were associated with ADCs that did not differentiate the two tumors.

CONCLUSION: Low b value images demonstrated superior anatomical details when compared to high b value images. Tumor tissue definition was high and contrast with the surrounding tissues was good. DWI was useful in diagnosing pancreatic cancer.

Keywords: Pancreatic cancer, Magnetic resonance imaging, b value, Apparent diffusion coefficient, Diffusion weighted imaging

Core tip: In this study, we retrospectively analyzed the conventional magnetic resonance imaging and diffusion weighted imaging (DWI) characteristics of 33 cases of pancreatic cancer using different b values, and assessed the value of the DWI examination in differentiating pancreatic cancer from benign pancreatic tumors.