Validation of functional imaging with pathology for tumor delineation in the prostate

IntroductionA study was performed to validate magnetic resonance (MR) based prostate tumor delineations with pathology.Material and methodsFive patients with biopsy proven prostate cancer underwent a T2 weighted (T2w), diffusion weighted MRI (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) scan before prostatectomy. Suspicious regions were delineated based on all available MR information. After prostatectomy whole-mount hematoxylin–eosin stained (H&E) sections were made. Tumor tissue was delineated on the H&E stained sections and compared with the MR based delineations. The registration accuracy between the MR images and H&E stained sections was estimated.ResultsA tumor coverage of 44–89% was reached by the MR based tumor delineations. The application of a margin of ∼5 mm to the MR based tumor delineations yielded a tumor coverage of 85–100% in all patients. Errors created during the registration procedure were 2–3 mm, which cannot completely explain the limited tumor coverage.ConclusionsAn accurate tissue processing and registration method was presented (registration error 2–3 mm), which enables the validation of MR based tumor delineations with pathology. Reasonable tumor coverage of about 85% and larger was found when applying a margin of ∼5 mm to the MR based tumor delineations.