Comparison of 5 T and 3 T Biparametric MRI for Clinically Suspected Prostate Cancer: Image Quality, Lesion Visualization, and Artifacts.

BACKGROUND

Biparametric MRI (bpMRI) is important for prostate cancer (PCa) diagnosis. Higher field strength at 5 T may improve image quality versus 3 T, but clinical value remains unclear.

PURPOSE: To compare image quality, imaging artifacts, and PCa visualization between 3 T and 5 T bpMRI.

STUDY TYPE: Prospective.

POPULATION: One hundred and five patients with clinically suspected PCa, including 56 with histologically proven prostatic lesions.

FIELD STRENGTH/SEQUENCE: 3 T and 5 T; T2-weighted imaging (T2WI) using fast spin echo and echo-planar diffusion-weighted imaging (DWI).

ASSESSMENT: Signal-to-noise ratio (SNR) measured at both field strengths; in the biopsy-proven cancer subset, contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and lesion-boundary sharpness measured using the "plot profile" function. Image quality and lesion conspicuity rated on 5-point Likert scales. Prostate imaging reporting and data system (PI-RADS) v2.1 agreement was compared using Cohen κ. Participants were grouped by pre-scan enema (enema n = 61; non-enema n = 44) for artifact comparisons.

STAISTICAL TESTS: Wilcoxon signed-rank test, ICC, and Cohen's κ; p < 0.05 was considered significant.

RESULTS

5 T demonstrated significantly higher SNR for T2WI (391.40 vs. 274.41) and DWI (208.82 vs. 106.40). CNR was higher at 5 T for T2WI (median 10.3 vs. 8.5) and DWI (median 31.5 vs. 16.2); lesion-edge sharpness was greater at 5 T (median 48.1%/mm vs. 30.9%/mm). Median scores for image quality, lesion conspicuity, and anatomy visibility were higher at 5 T than at 3 T (4-5 vs. 3-4). DWI artifacts were more frequent at 5 T in the non-enema group (5 T 20%-27% vs. 3 T 11%-16%); other artifact comparisons were not significant (p = 0.059-0.886). PI-RADS scoring showed excellent inter-reader agreement (κ = 0.83-0.95) and good inter-field agreement (κ = 0.69-0.89).

DATA

CONCLUSION

In bpMRI, 5 T has significantly better T2WI and DWI image quality than 3 T.

EVIDENCE LEVEL: 2.

TECHNICAL EFFICACY: Stage 3.