Original Article
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Dec 14, 2009; 15(46): 5805-5812
Published online Dec 14, 2009. doi: 10.3748/wjg.15.5805
Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions
Naoto Koike, Akihiro Cho, Katsuhiro Nasu, Kazuhiko Seto, Shigeyuki Nagaya, Yuji Ohshima, Nobuhiro Ohkohchi
Naoto Koike, Yuji Ohshima, Department of Surgery, Seirei Sakura Citizen Hospital, 2-36-2 Ebaradai, Sakura, Chiba 285-8765, Japan
Akihiro Cho, Department of Surgery, Chiba Cancer Center, 666-2 Nitona, Chuhohku, Chiba 260-8717, Japan
Katsuhiro Nasu, Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
Kazuhiko Seto, Department of Radiology, Seirei Sakura Citizen Hospital, 2-36-2 Ebaradai, Sakura, Chiba 285-8765, Japan
Shigeyuki Nagaya, Department of Radiology, Seirei Mikatabara Hospital, 3453 Mikatabara, Kitaku, Hamamatsu, Shizuoka 433-8558, Japan
Nobuhiro Ohkohchi, Department of Surgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
Author contributions: Koike N wrote the paper; Cho A designed research; Koike N, Seto K, Nagaya S and Ohshima Y contributed to the imaging processing and analysis; Nasu K and Ohkohchi N critically revised the paper with an important conceptual and editorial input.
Correspondence to: Dr. Naoto Koike, Department of Surgery, Seirei Sakura Citizen Hospital, 2-36-2 Ebaradai, Sakura, Chiba 285-8765, Japan. naotk@sis.seirei.or.jp
Telephone: +81-43-4861151 Fax: +81-43-4868696
Received: August 15, 2009
Revised: October 26, 2009
Accepted: November 2, 2009
Published online: December 14, 2009
Abstract

AIM: To evaluate the utility of diffusion-weighted imaging (DWI) in screening and differential diagnosis of benign and malignant focal hepatic lesions.

METHODS: Magnetic resonance imaging (MRI) examinations were performed using the Signa Excite Xl Twin Speed 1.5T system (GE Healthcare, Milwaukee, WI, USA). Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas (HCC), four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio (RCR), and apparent diffusion coefficient (ADC) were compared between benign and malignant lesions on DWI. Superparamagnetic iron oxide (SPIO) was administered to 59 patients, and RCR was compared pre- and post-administration.

RESULTS: DWI showed higher contrast between malignant lesions (especially in multiple small metastatic cancers) and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs (mean ± SD × 10-3 mm2/s) were significantly lower (P < 0.05) in malignant lesions (HCC: 1.31 ± 0.28 and liver metastasis: 1.11 ± 0.22) and were significantly higher in benign lesions (hemangioma: 1.84 ± 0.37 and cyst: 2.61 ± 0.45) than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding hepatic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.

CONCLUSION: DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.

Keywords: Hepatic tumor; Liver imaging; Magnetic resonance imaging; Diffusion-weighted imaging; Apparent diffusion coefficient