Advanced diffusion weighted imaging of the prostate: Comparison of readout-segmented multi-shot, parallel-transmit and single-shot echo-planar imaging.

PURPOSE

This study evaluates objective and subjective image quality (IQ) of three different diffusion weighted imaging (DWI) sequences in prostate MRI at 3.0 Tesla within the same patients.

METHOD

Thirty-six consecutive patients (70 ± 8 years) with multi-parametric prostate MRI (mp-MRI; 3 T) and subsequently verified prostate cancer (PCa) by targeted plus systematic MR/US-fusion biopsy from 03/2016 to 12/2017 were included. Readout-segmented (rs) multi shot echo-planar imaging (EPI), parallel transmit (ptx) EPI, and single-shot (ss) EPI with b-values of 0, (500,) 1,000 s/mm² and calculated b1,500 were prospectively acquired of every patient. Signal intensities (SI) of PCa and benign tissue (peripheral and transition zone; PZ and TZ) in ADC, b1,000, and calculated b1,500 images were analyzed. Endpoints were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective IQ on a 5-point scale by two blinded readers.

RESULTS

For ss-EPI ADC, b-values of 1,000, and calculated 1,500 s/mm² images showed a higher SNR compared to rs-EPI and ptx-EPI (p < 0.01). CNR of PCa and benign tissue was significantly higher for rs-EPI in high b value images compared to ptx-EPI and ss-EPI (p < 0.01). Subjective IQ was significantly higher for rs-EPI (p < 0.01). Significantly higher ADC reduction combined with signal increase on high b value images for PCa compared to the surrounding healthy tissue in PZ and TZ (PCa contrast intensity) was detected for rs-EPI (p < 0.01). Single PCa lesions could only be recognized and correlated on rs-EPI.

CONCLUSIONS

Rs-EPI and ptx-EPI were superior to ss-EPI regarding contrast intensity of PCA, but inferior regarding SNR. Subjective imaging parameters were superior for rs-EPI. Especially rs-EPI, but also ptx-EPI might improve and faciliate prostate cancer detection, rs-EPI at the expense of a longer acquisition time.