Value of Magnetic Resonance Spectroscopy Imaging and Dynamic Contrast-Enhanced Imaging for Detecting Prostate Cancer Foci in Men With Prior Negative Biopsy

Abstract

Purpose: This study aimed to prospectively analyze the role of magnetic resonance spectroscopy imaging (MRSI) and dynamic-contrast enhancement magnetic resonance (DCEMR) in the detection of prostate tumor foci in patients with persistently elevated prostate-specific antigen levels (in the range of ≥4 ng/mL to <10 ng/mL) and prior negative random trans-rectal ultrasound (TRUS)-guided biopsy.Experimental Design: This was a prospective randomized single-center study. One hundred and eighty eligible cases were included in the study. Patients in group A were submitted to a second random prostate biopsy, whereas patients in group B were submitted to a 1 H-MRSI-DCEMR examination and samples targeted on suspicious areas were associated to the random biopsy.Results: At the second biopsy, a prostate adenocarcinoma histologic diagnosis was found in 22 of 90 cases (24.4%) in group A and in 41 of 90 cases (45.5%) in group B (P = 0.01). On a patient-by-patient basis, MRSI had 92.3% sensitivity, 88.2% specificity, 85.7% positive predictive value (PPV), 93.7% negative predictive value (NPV), and 90% accuracy; DCEMR had 84.6 % sensitivity, 82.3% specificity, 78.5% PPV, 87.5% NPV, and 83.3% accuracy; and the association MRSI plus DCEMR had 92.6% sensitivity, 88.8% specificity, 88.7% PPV, 92.7% NPV, and 90.7% accuracy, for predicting prostate cancer detection.Conclusions: The combination of MRSI and DCEMR showed the potential to guide biopsy to cancer foci in patients with previously negative TRUS biopsy. To avoid a potential bias, represented from having taken more samples in group B (mean of cores, 12.17) than in group A (10 cores), in the future a MRSI/ DCEMR directed biopsy could be prospectively compared with a saturation biopsy procedure. Clin Cancer Res; 16(6); 1875-83. ©2010 AACR.At present, suspicion of prostate adenocarcinoma is mainly based on three tests: digital rectal examination, prostate-specific antigen (PSA), and trans-rectal ultrasound (TRUS), and is confirmed by TRUS-guided biopsies. The latter is recognized by urologists as the first choice in the diagnosis of prostate pathologies (1). All three modern imaging modalities, namely, computer tomography, ultrasonography, and magnetic resonance (MR), have been considered to have limitations in the diagnosis of prostate adenocarcinoma. Recently some studies (2-5) revealed the high diagnostic accuracy of combined proton 1H-magnetic resonance spectroscopic imaging (1H-MRSI) and dynamic contrast-enhanced imaging magnetic resonance (DCEMR) in the management of prostate cancer. The advantage of MRSI is that the spectroscopic analysis provides metabolic information regarding prostatic tissue by displaying the relative concentrations of chemical compounds within contiguous small volumes of interest (voxels). In the prostate the substances analyzed by MRSI are citrate, creatine, and choline. For practical purposes, prostate adenocarcinoma can be distinguished from healthy peripheral zone tissue on the basis of the (choline + creatine)/citrate ratio (5-7). Normal per...

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