performance characteristics of mpmri at centers of excellence peter choyke, md national cancer...
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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