Multiparametric 3T endorectal MRI after external beam radiation therapy for prostate cancer - Abstract

PURPOSE:To determine the best combination of magnetic resonance imaging (MRI) parameters for the detection of locally recurrent prostate cancer after external beam radiation therapy.

MATERIALS AND METHODS: Our Institutional Review Board approved this study with a waiver of informed consent. Twenty-six patients with suspected recurrence due to biochemical failure were part of this research. The MR protocol included T2-weighted, MR spectroscopy, and diffusion-weighted MRI. Transrectal ultrasound-guided biopsy was the standard of reference. We used logistic regression to model the probability of a positive outcome and generalized estimating equations to account for clustering. The diagnostic performance of imaging was described using receiver operating characteristic (ROC) curves.

RESULTS: The area under the ROC curve of MR spectroscopic imaging (MRSI) was 83.0% (95% confidence interval [CI] = 75.5-89.1). The combination of all MR techniques did not significantly improve the performance of imaging beyond the accuracy of MRSI alone, but a trend toward improved discrimination was noted (86.9%; 95% CI = 77.6-93.4; P = 0.09).

CONCLUSION: Incorporation of MRSI to T2-weighted and/or diffusion-weighted MRI significantly improves the assessment of patients with suspected recurrence after radiotherapy and a combined approach with all three modalities may have the best diagnostic performance.

Written by:
Westphalen AC, Reed GD, Vinh PP, Sotto C, Vigneron DB, Kurhanewicz J. Are you the author?
Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.

Reference: J Magn Reson Imaging. 2012 Apr 25. Epub ahead of print.
doi: 10.1002/jmri.23672

PubMed Abstract
PMID: 22535708

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