Test-retest repeatability of ADC in prostate using the multi b-Value VERDICT acquisition.

Area of Science:

• Radiology and Imaging Science
• Oncology Imaging
• Medical Physics

Background:

• Vascular, Extracellular, Restricted Diffusion for Cytometry in Tumours (VERDICT) MRI is an advanced diffusion-weighted imaging (DWI) technique.
• It utilizes multi b-value and variable diffusion time sequences to generate apparent diffusion coefficient (ADC) maps.
• Accurate ADC measurements are crucial for prostate cancer characterization and monitoring.

Purpose of the Study:

• To evaluate the precision of prostate ADC measurements derived from various b-value combinations using VERDICT MRI.
• To identify the optimal VERDICT MRI protocol that yields the most repeatable ADC values.
• To assess the impact of different b-value combinations on ADC measurement repeatability in prostate tissues.

Main Methods:

• Retrospective analysis of 41 men with suspected prostate cancer who underwent two VERDICT MRI scans.
• ADC maps were generated using five different b-value combinations.
• Within-subject standard deviations (wSD) were calculated for ADC values in normal transition zone (TZ), peripheral zone (PZ), and index lesions. Statistical analyses included repeated measures ANOVAs and regression models.

Main Results:

• The b0b1500 b-value combination demonstrated the lowest wSD for mean lesion ADC in most analyzed zones.
• ADC magnitude and lesion Likert score did not significantly affect wSD.
• wSD decreased with increasing Region of Interest (ROI) size, indicating improved repeatability with larger ROIs.

Conclusions:

• ADC maps generated using the b0b1500 combination exhibit superior repeatability in normal prostate zones and index lesions.
• The b0b1500 protocol is recommended for precise and reproducible ADC measurements in prostate cancer imaging.
• VERDICT MRI with optimized b-value selection enhances diagnostic confidence in prostate cancer assessment.