Differentiation of prostate cancer lesions with high and with low Gleason score by diffusion-weighted MRI.
OBJECTIVE
To differentiate prostate cancer lesions with high and with low Gleason score by diffusion-weighted-MRI (DW-MRI).


METHODS
This prospective study was approved by the responsible ethics committee. DW-MRI of 84 consenting prostate and/or bladder cancer patients scheduled for radical prostatectomy were acquired and used to compute apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM: the pure diffusion coefficient Dt, the pseudo-diffusion fraction Fpand the pseudo-diffusion coefficient Dp), and high b value (as acquired and Hessian filtered) parameters within the index lesion. These parameters (separately and combined in a logistic regression model) were used to differentiate lesions depending on whether whole-prostate histopathological analysis after prostatectomy determined a high (≥7) or low (6) Gleason score.


RESULTS
Mean ADC and Dtdiffered significantly (p of independent two-sample t test < 0.01) between high- and low-grade lesions. The highest classification accuracy was achieved by the mean ADC (AUC 0.74) and Dt(AUC 0.70). A logistic regression model based on mean ADC, mean Fpand mean high b value image led to an AUC of 0.74 following leave-one-out cross-validation.


CONCLUSIONS
Classification by IVIM parameters was not superior to classification by ADC. DW-MRI parameters correlated with Gleason score but did not provide sufficient information to classify individual patients.


CONCLUSIONS
• Mean ADC and diffusion coefficient differ between high- and low-grade prostatic lesions. • Accuracy of trivariate logistic regression is not superior to using ADC alone. • DW-MRI is not a valid substitute for biopsies in clinical routine yet.
Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital University Hospital, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
Sebastiano
S
Barbieri
Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital University Hospital, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
Michael
M
Brönnimann
Department of Urology, Inselspital, Inselspital University Hospital, Bern, Switzerland.
Silvan
S
Boxler
Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital University Hospital, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland.
Peter
P
Vermathen
Institute of Diagnostic, Pediatric, and Interventional Radiology, Inselspital University Hospital, Inselspital, Freiburgstrasse 10, CH-3010, Bern, Switzerland. Harriet.Thoeny@insel.ch.
Harriet C
HC
Thoeny
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011446:Prospective Studies; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery
ADC; Diffusion-weighted MRI; IVIM; Logistic regression; Prostate cancer