Prostate MRI

Dr. A. Stockman

Indications

• Tumour detection or exclusion in patients with clinical suspicion of prostate cancer – Elevated PSA > 4.0 ng/mL – Rising PSA – Suspicious digital rectal exam (DRE) – Negative biopsy but continuous clinical suspicion of prostate cancer

• Staging of patients with known prostate cancer – Curative intent – Active surveillance

Benefits Prostate MRI

• Noninvasive imaging technique

• No ionizing radiation

• Early detection

• Localisation

• Risk stratification

• Extent of prostate cancer / staging

Zonal anatomy

• Base 6 sectors on each side: – AS: anterior fibromuscular stroma – TZ: anterior and posterior transition zone – PZ: anterior and posterior zone – CZ: central zone around the ejaculatory ducts

• Midportion 6 sectors on each side: – AS: anterior fibromuscular stroma – TZ: anterior and posterior transition zone – PZ: anterior, posteromedial and posterolateral peripheral zone

• Apex 6 sectors on each side: – AS: anterior fibromuscular stroma – TZ: anterior and posterior transition zone – PZ: anterior, posteromedial and posterolateral peripheral zone

• Seminal vesicles

Prostate cancer risk– zonal anatomy

• Peripheral zone (PZ): 70-75%

• Transition zone (TZ): 25%

• Central zone (CZ):

PI-RADS v2

• Prostate Imaging Reporting and Data System • Standardized acquisition, interpretation and reporting of prostate

MRI. • Multiparametric MRI • T2-weighted (T2W) • Diffusion weighted imaging (DWI) • Apparent diffusion coefficient (ADC) • Dynamic contrast-enhanced imaging (DCE)

PI-RADS v2

• PI-RADS 1: very low (clinically significant cancer is highly unlikely to be present)

• PI-RADS 2: low (clinically significant cancer is unlikely to be present)

• PI-RADS 3: intermediate (the presence of clinically significant cancer is equivocal)

• PI-RADS 4: high (clinically significant cancer is likely to be present)

• PI-RADS 5: very high (clinically significant cancer is highly likely to be present)

Results

The PIRADS score provides an effective framework for determining the likelihood of prostate cancer on MRI.

• PPV* of PI-RADS 3: 10.6% • PPV* of PI-RADS 4: 44% • PPV* of PI-RADS 5: 100% * positive predictive values

E. NiMhurchu, et al. Predictive value of PI-RADS classification in MRI-directed transrectal ultrasound guided prostate biopsy. Clinical Radiology. 2016; Volume 71, Issue 4, Pages 375–380.

US/MRI fusion

•Targets identified in MRI/PI-RADs report

• Importing a PI-RADS report

•PI-RAD Sector of Interest aligned

with live B-Mode Image

FusionVu using a PI-RADS Report

US/MRI fusion

•Targets identified in MRI/PI-RADs report

• Importing annotated MR images

•Annotated MR images aligned

with live micro-ultrasound image

FusionVu using a MRI