1 research outputs found
The Role of Multiparametric MRI in Detection, Localization and Characterization of Prostate Cancer
Our aim was to detect the performance characteristics of multiparametric magnetic resonance imaging (mp-MRI) in patients with clinical suspicion, or previous diagnosis, of prostate cancer. Mp-MRI (index test) comprised of T2-weighted, diffusion weighted and dynamic contrast enhanced imaging. Radiologists used Likert score 1-5 based on the likelihood of the presence of prostate cancer. Concordance was made between results of mp- MRI and template prostate mapping (TPM) biopsy (reference standard). This retrospective study included patients that had both the index test and reference standard between January 2007 to January 2011 at either University College London Hospital or London Urology Associates.. These were patients with; a) no prior prostate biopsy (n=129), b) prior negative prostate biopsy (n=54), c) previous positive prostate biopsy (n=194) and d) biochemical failure after radiotherapy (n=37). A set of target conditions was used and varied between the four groups of patients. These were either based on Gleason scoring, maximum cancer core length or a combination of both. In the first group, mp-MRI showed encouraging diagnostic performance results in ruling out clinically significant prostate cancer with sensitivity and negative predictive value (NPV) up to 94% and 89%, respectively. Accuracy figures were similar in the second group with sensitivity and NPV reaching up to 90% and 95%, respectively. In patients that underwent mp-MRI before reclassification TPM biopsy (third group), NPV for predicting that cancer remained low risk (as detected on previous TRUS-guided biopsy) reached up to 100%. Positive predictive value for upgrade of prostate cancer disease on subsequent TPM biopsy reached up to 75% with diagnostic odds ratio up to 2.86. In the last group, a combination of T2-weighted + high b-value showed optimum mp-MRI performance. These results suggest that mp-MRI can be used as a triage test among different patient populations, to select patients that can avoid biopsy and those that need re-biopsy before entering an active surveillance program. Time and cost can be saved by using only certain MRI sequences in patients with biochemical failure after radiotherapy