Multiparametric MRI for detection of radiorecurrent prostate cancer: added value of apparent diffusion coefficient maps and dynamic contrast-enhanced images
Menée sur 37 patients atteints d'un cancer de la prostate avec récidive biochimique après radiothérapie externe (âge moyen : 69,7 ans), cette étude évalue la performance d'une IRM multiparamétrique pour détecter une récidive tumorale et analyse l'intérêt d'une cartographie du coefficient de diffusion apparent ou d'un rehaussement dynamique du contraste des images pour améliorer la précision du diagnostic
Background : Multiparametric magnetic resonance imaging (mp-MRI) is increasingly advocated for prostate cancer detection. There are limited reports of its use in the setting of radiorecurrent disease. Our aim was to assess mp-MRI for detection of radiorecurrent prostate cancer and examine the added value of its functional sequences.
Methods : Thirty-seven men with mean age of 69.7 (interquartile range, 66–74) with biochemical failure after external beam radiotherapy underwent mp-MRI (T2-weighted, high b-value, multi-b-value apparent diffusion coefficient (ADC) and dynamic contrast-enhanced (DCE) imaging); then transperineal systematic template prostate mapping (TPM) biopsy. Using a locked sequential read paradigm (with the sequence order above), two experienced radiologists independently reported mp-MRI studies using score 1–5. Radiologist scores were matched with TPM histopathology at the hemigland level (n=74). Accuracy statistics were derived for each reader. Interobserver agreement was evaluated using kappa statistics.
Results : Receiver–operator characteristic area under curve (AUC) for readers 1 and 2 increased from 0.67 (95% confidence interval (CI), 0.55–0.80) to 0.80 (95% CI, 0.69–0.91) and from 0.67 (95% CI, 0.55–0.80) to 0.84 (95% CI, 0.76–0.93), respectively, between T2-weighted imaging alone and full mp-MRI reads. Addition of ADC maps and DCE imaging to the examination did not significantly improve AUC for either reader (P=0.08 and 0.47 after adding ADC, P=0.90 and 0.27 after adding DCE imaging) compared with T2+high b-value review. Inter-reader agreement increased from k=0.39 to k=0.65 between T2 and full mp-MRI review.
Conclusions : mp-MRI can detect radiorecurrent prostate cancer. The optimal examination included T2-weighted imaging and high b-value DWI; adding ADC maps and DCE imaging did not significantly improve the diagnostic accuracy.
Prostate Cancer and Prostatic Diseases , résumé, 2014