Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Radiol. Jul 28, 2012; 4(7): 302-310
Published online Jul 28, 2012. doi: 10.4329/wjr.v4.i7.302
Diffusion-weighted MRI in a liver protocol: Its role in focal lesion detection
Stefano Palmucci, Letizia Antonella Mauro, Martina Messina, Brunella Russo, Giovanni Failla, Pietro Milone, Massimiliano Berretta, Giovanni Carlo Ettorre
Stefano Palmucci, Letizia Antonella Mauro, Martina Messina, Brunella Russo, Giovanni Failla, Pietro Milone, Giovanni Carlo Ettorre, Radiodiagnostic and Oncological Radiotherapy Unit, University Hospital “Policlinico-Vittorio Emanuele”, 95123 Catania, Italy
Massimiliano Berretta, Department of Medical Oncology, National Cancer Institute, 33081 Aviano (PN), Italy
Author contributions: Palmucci S, Messina M and Russo B planned the research, performed the study and analyzed the data; Ettorre GC approved the research; Milone P provided some magnetic resonance imaging studies; Palmucci S and Berretta M were involved in the collection of clinical data; Palmucci S and Failla G critically revised the data; Palmucci S wrote the paper, assisted by Russo B and Messina M; and Mauro LA corrected the manuscript.
Correspondence to: Stefano Palmucci, MD, Radiodiagnostic and Oncological Radiotherapy Unit, University Hospital “Policlinico-Vittorio Emanuele”, 95123 Catania, Italy. spalmucci@sirm.org
Telephone: +39-095-3782360 Fax: +39-095-3782360
Received: September 8, 2011
Revised: February 21, 2012
Accepted: March 1, 2012
Published online: July 28, 2012
Abstract

AIM: To evaluate the role of diffusion-weighted imaging (DWI) in the detection of focal liver lesions (FLLs), using a conventional magnetic resonance imaging (MRI) protocol.

METHODS: Fifty-two patients (22 males, average age 55.6 years, range: 25-82 years), studied using a 1.5 Tesla magnetic resonance scanner, were retrospectively analyzed; detection of FLLs was evaluated by considering the number of lesions observed with the following sequences: (1) respiratory-triggered diffusion-weighted single-shot echo-planar (DW SS-EP) sequences; (2) fat-suppressed fast spin-echo (fs-FSE) T2 weighted sequences; (3) steady-state free precession (SSFP) images; and (4) dynamic triphasic gadolinium-enhanced images, acquired with three-dimensional fast spoiled gradient-echo (3D FSPGR). Two radiologists independently reviewed the images: they were blinded to their respective reports. DW SS-EP sequences were compared to fs-FSE, SSFP and dynamic gadolinium-enhanced acquisitions using a t-test. Pairs were compared for the detection of: (1) all FLLs; (2) benign FLLs; (3) malignant FLLs; (4) metastases; and (5) hepatocellular carcinoma (HCC).

RESULTS: Interobserver agreement was very good (weighted κ = 0.926, CI = 0.880-0.971); on the consensus reading, 277 FLLs were detected. In the comparison with fs-FSE, DW SS-EP sequences had a significantly higher score in the detection of all FLLs, benign FLLs, malignant FLLs and metastases; no statistical difference was observed in the detection of hepatocellular carcinoma (HCCs). In the comparison with SSFP sequences, DW SS-EP had significantly higher scores (P < 0.05) in the detection of all lesions, benign lesions, malignant lesions, metastases and HCC. All FLLs were better detected by dynamic 3D FSGR enhanced acquisition, with P = 0.0023 for reader 1 and P = 0.0086 for reader 2 in the comparison with DW SS-EP sequences; with reference to benign FLLs, DW SS-EP showed lower values than 3D FSPGR enhanced acquisition (P < 0.05). No statistical differences were observed in the detection of malignant lesions and metastases; considering HCCs, a very slight difference was reported by reader 1 (P = 0.049), whereas no difference was found by reader 2 (P = 0.06).

CONCLUSION: In lesion detection, DWI had higher scores than T2 sequences; considering malignant FLLs, no statistical difference was observed between DWI and dynamic gadolinium images.

Keywords: Diffusion weighted magnetic resonance imaging, Liver, Liver disease, Magnetic resonance imaging