Objective:

To evaluate the diagnostic performance and interreader agreement of Prostate Magnetic Resonance Imaging for Local Recurrence Reporti

ng (PI-RR) using whole-mount histology of prostate after androgen deprivation therapy (ADT) as the standard of reference.

Methods:

Totally 119 post-ADT prostate cancer patients underwent multiparametric MRI (mpMRI) before prostatectomy. Three radiologists analyzed MRI images independently

scoring imaging findings according to PI- RR. Diagnosis performances for detection of residual cancer were assessed on per-sector basis. The cancer detection rate (CDR) was compared among readers with

χ

2

test. Overall and pairwise interreader agreement in assigning PI-RR scores and residual cancer sector with score≥3 or 4 were evaluated by Cohen’s Kappa analysis.

Results:

Two hundred and nine sectors with residual cancer were found on histology. The sensitivity

specificity

positive predictive value and negative predictive value at cutoff of score 3 ranged from 74.2% to 83.7%

86.4% to 92.7%

51.3% to 64.3%

and 95.4% to 96.9%

respectively

and at cutoff of 4

they ranged from 47.4% to 56.5%

97.9% to 98.6%

82.5% to 85.3%

and 91.6% to 92.9%

respectively. There was no significant difference among theCDR of readers. In PI-RR scores and detection of residual cancer sectors

overall interreader agreement was moderate for all readers

but agreement was higher between senior and intermediate readers (moderate to substantial) than between intermediate and junior readers (fair to moderate).

Conclusion:

MRI scoring with the PI-RR assessment provides accurate evaluation of prostate cancer after ADT

but readers’ experience influenced cancer diagnosis and interreader agreement.