Performance Characteristics of mpMRI at Centers of Excellence

Peter Choyke, MDNational Cancer Institute

Optimizing Prostate MRI

• Before the MRI– Dedicated personnel who:

• Access medical records• Obtain history• PSA• Prior biopsy results with location and Gleason score• Understand the purpose of the examination• Safety check for implants• Evacuate bladder and bowel

Optimizing Prostate MRI• During the MRI

– Assure patient comfort to reduce motion– 3T or late model 1.5T with or without ERC

• Dedicated Technologist(s)• Same machine

– High quality T2 (no fat sat)– Diffusion weighted MRI

• Use b values between 100-1000 for ADC• High b value image above 1500

– DCE MRI with temporal resolution <7 sec• Carry out to 4 minutes

Optimizing Prostate MRI

• After the Exam– Rapid structured report

• PI-RADS v2 format• PI-RADS Map

– Images transferred to workstation for MR-US fusion biopsy

• Segment the prostate• Localize the lesions• Follow-up on path report

The PIRADS v2 mappingSchema

Limitations

• Total Hip Replacement• Motion• Obesity• False borders of the tumor

– Careful correlation with histology– Corona effect

Patient-Specific MR-based MoldShah et al. Rev Sci Instrum. 2009 Oct;80(10):104301 (Research Highlight for Oct’09 issue)

Tissue Blocks Obtained from Prostatectomy Specimen

Virtual MoldT2W 3D Printing Mold

Printed at CIT, NIH

Marcelino Bernardo

Follow-up of Ablations

• Requires careful uniform imaging in followup• Surrogates of residual disease:

– Enhancement– DWI– PET agents?

Pre-treatment T2W MRI

Pre-treatment ADC map

Pre-treatment DCE MRI

Post-treatment T2W MRI

Post-treatment ADC map

Post-treatment DCE MRI

PET Imaging of Residual Disease

58, M,

PSA=8.2

Gleason 3+4 tumor

Summary

• Center of Excellence requires attention to detail before, during and after the MRI

• There are a number of important limitations of MRI in performing/monitoring ablation that must be acknowledged

• MRI for followup of ablation can be non-specific.– Newer PET agents may be helpful in detecting

recurrence