Intravoxel incoherent motion model–based analysis of diffusion-weighted magnetic resonance imaging with 3 b-values for response assessment in locoregional therapy of hepatocellular carcinoma
Authors Mürtz P, Penner AH, Pfeiffer AK, Sprinkart AM, Pieper CC, König R, Block W, Schild HH, Willinek WA, Kukuk GM
Received 30 May 2016
Accepted for publication 5 August 2016
Published 19 October 2016 Volume 2016:9 Pages 6425—6433
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Jia Fan
Peer reviewer comments 2
Editor who approved publication: Dr Yao Dai
Petra Mürtz, Arndt-Hendrik Penner, Anne-Kristina Pfeiffer, Alois M Sprinkart, Claus C Pieper, Roy König, Wolfgang Block, Hans H Schild, Winfried A Willinek, Guido M Kukuk
Department of Radiology, University of Bonn, Bonn, Germany
Purpose: The aim of this study was to evaluate an intravoxel incoherent motion (IVIM) model–based analysis of diffusion-weighted imaging (DWI) for assessing the response of hepatocellular carcinoma (HCC) to locoregional therapy.
Patients and methods: Respiratory-gated DWI (b=0, 50, and 800 s/mm2) was retrospectively analyzed in 25 patients who underwent magnetic resonance imaging at 1.5 T before and 6 weeks following the first cycle of transarterial chemoembolization therapy, transarterial ethanol-lipiodol embolization therapy, and transarterial radioembolization therapy. In addition to the determination of apparent diffusion coefficient, ADC(0,800), an estimation of the diffusion coefficient, D', and the perfusion fraction, f', was performed by using a simplified IVIM approach. Parameters were analyzed voxel-wise. Tumor response was assessed in a central slice by using a region of interest (ROI) covering the whole tumor. HCCs were categorized into two groups, responders and nonresponders, according to tumor size changes on first and second follow ups (if available) and changes of contrast-enhanced region on the first follow up.
Results: In total, 31 HCCs were analyzed: 17 lesions were assigned to responders and 14 were to nonresponders. In responders, ADC(0,800) and D' were increased after therapy by ~30% (P=0.00004) and ~42% (P=0.00001), respectively, whereas f' was decreased by ~37% (P=0.00094). No significant changes were found in nonresponders. Responders and nonresponders were better differentiated by changes in D' than by changes in ADC(0,800) (area under the curve =0.878 vs 0.819 or 0.714, respectively).
Conclusion: In patients with HCCs undergoing embolization therapy, diffusion changes were better reflected by D' than by conventional ADC(0,800), which is influenced by counteracting perfusion changes as assessed by f'.
Keywords: MRI, DWI, IVIM, HCC, locoregional therapy, therapy monitoring
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