How accurate is multiparametric MR imaging in evaluation of prostate cancer volume? - Abstract

Purpose: To assess the factors influencing multiparametric ( MP multiparametric ) magnetic resonance (MR) imaging accuracy in estimating prostate cancer histologic volume ( Vh histologic volume ).

Materials and Methods: A prospective database of 202 patients who underwent MP multiparametric MR imaging before radical prostatectomy was retrospectively used. Institutional review board approval and informed consent were obtained. Two independent radiologists delineated areas suspicious for cancer on images (T2-weighted, diffusion-weighted, dynamic contrast material-enhanced [ DCE dynamic contrast enhanced ] pulse sequences) and scored their degree of suspicion of malignancy by using a five-level Likert score. One pathologist delineated cancers on whole-mount prostatectomy sections and calculated their volume by using digitized planimetry. Volumes of MR true-positive lesions were measured on T2-weighted images ( VT2 volume measured on a T2-weighted image ), on ADC apparent diffusion coefficient maps ( VDCE volume measured on an ADC map ), and on DCE dynamic contrast enhanced images [ VDCE volume measured on a DCE image ]). VT2 volume measured on a T2-weighted image , VDCE volume measured on an ADC map, VDCE volume measured on a DCE image and the greatest volume determined on images from any of the individual MR pulse sequences ( Vmax greatest volume determined with images from any of the individual MR pulse sequences ) were compared with Vh histologic volume (Bland-Altman analysis). Factors influencing MP multiparametric MR imaging accuracy, or A, calculated as A = Vmax greatest volume determined with images from any of the individual MR pulse sequences / Vh histologic volume, were evaluated using generalized linear mixed models.

Results: For both readers, Vh histologic volume was significantly underestimated with VT2 volume measured on a T2-weighted image (P < .0001, both), VADC volume measured on an ADC map (P < .0001, both), and VDCE volume measured on a DCE image (P = .02 and P = .003, readers 1 and 2, respectively), but not with Vmax greatest volume determined with images from any of the individual MR pulse sequences (P = .13 and P = .21, readers 1 and 2, respectively). Mean, 25th percentile, and 75th percentile, respectively, for Vmax greatest volume determined with images from any of the individual MR pulse sequences accuracy were 0.92, 0.54, and 1.85 for reader 1 and 0.95, 0.57, and 1.77 for reader 2. At generalized linear mixed (multivariate) analysis, tumor Likert score (P < .0001), Gleason score (P = .009), and Vh histologic volume (P < .0001) significantly influenced Vmax greatest volume determined with images from any of the individual MR pulse sequences accuracy (both readers). This accuracy was good in tumors with a Gleason score of 7 or higher or a Likert score of 5, with a tendency toward underestimation of Vh histologic volume ; accuracy was poor in small (< 0.5 cc) or low-grade (Gleason score ≤ 6) tumors, with a tendency toward overestimation of Vh histologic volume .

Conclusion: Vh histologic volume can be estimated by using Vmax greatest volume determined with images from any of the individual MR pulse sequences in aggressive tumors or in tumors with high Likert scores.

Written by:
Bratan F, Melodelima C, Souchon R, Dinh AH, Mège-Lechevallier F, Crouzet S, Colombel M, Gelet A, Rouvière O.   Are you the author?
Departments of Urinary and Vascular Radiology, Pathology, and Urology, Hospices Civils de Lyon, Hôpital Edouard Herriot, 5 place d'Arsonval, 69437 Lyon Cedex 03, France; Université de Lyon, Lyon, France; Université Lyon 1, Faculté de Médecine Lyon Est, Lyon, France; Inserm, U1032, LabTau, Lyon, France; Laboratoire d'Ecologie Alpine, Université Joseph Fourier, Grenoble, France; and CNRS, UMR 5553, Grenoble, France.

Reference: Radiology. 2014 Nov 21:140524.
doi: 10.1148/radiol.14140524


PubMed Abstract
PMID: 25423145

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