Validation of Whole Slide Imaging for the First Line Diagnosis of Prostate Biopsies
Joseph Zeitouni, Merce Jorda, Carolina Reyes, Mehrdad Nadji. University of Miami, Jackson Health System and Sylvester Cancer Center, Miami, FL
Background: Whole slide imaging (WSI) also known as virtual microscopy is becoming an important tool in diagnostic pathology. The high resolution of images and refinement of technology now allows for WSI to be used as an alternative to conventional microscopy (CM) as a first line diagnostic platform. We investigated that possibility by comparing the intra-pathologist reproducibility of histologic diagnosis of prostate biopsies by CM and WSI.
Design: Ninety-three needle biopsies of prostate were randomly selected for this study. Each slide was scanned at 20X by BioImagene iScan Coreo Au (Ventana Medical Systems, Tucson, AZ). Four pathologists with varying degrees of experience in prostate pathology independently reviewed the glass slides first by CM, and after an interval of one week by WSI, and then a second review by CM. Diagnostic categories included benign prostatic tissue, high grade PIN, prostatic carcinoma Gleason 6, prostatic carcinoma Gleason 7 and prostatic carcinoma Gleason >7. The intra-pathologist reproducibility was recorded for CM vs WSI. Also, for each pathologist, the variation between the first CM and the second CM was used as control of the baseline. The inter-pathologist reproducibility was not the focus of this study.
Results: The intra-observer variability for CM vs WSI was 2% (observer 1), 3% (observer 2), 2% (observer 3) and 2% (observer 4). The intra-observer variability for CM vs CM was 2%, 1%, 3% and 3% for observers 1, 2, 3 and 4 respectively (kappa=0.9875). All intra-pathologist diagnostic disagreements (CM vs CM and CM vs WSI) were between Gleason grades 6 and 7. There were no intra-observer disagreements in the diagnosis of benign versus malignant disease or for the Gleason >7 category.
Conclusions: The intra-observer variability in the diagnosis of prostate biopsies by WSI is the same as glass slide microscopy. Our results suggest that WSI could be used as an alternative to conventional microscopy for the first line diagnosis of prostate biopsies.
Monday, March 19, 2012 1:00 PM
Poster Session II # 311, Monday Afternoon