T2-weighted imaging of the prostate: Impact of the BLADE technique on image quality and tumor assessment.

PURPOSE: To retrospectively compare standard and BLADE T2-weighted imaging (T2WI) sequences of the prostate in terms of image quality and tumor assessment.
METHODS: 49 prostate cancer patients (64 ± 6 years) who underwent 3 T phased-array coil MRI before prostatectomy were included. T2WI was acquired using standard rectilinear and BLADE techniques. Two readers (R1, R2) independently localized the dominant lesion using T2WI alone and using multi-parametric imaging; recorded presence of extraprostatic extension (EPE) in each lobe; and scored lesion conspicuity and absence of motion artifact (1-5 scale; 5 = highest quality). A third reader, unblinded to pathology, placed ROIs to record tumor-to-peripheral-zone contrast. Standard and BLADE T2WI were compared using paired Wilcoxon tests.
RESULTS: BLADE showed a trend toward improved motion artifact for R1 (3.4 ± 1.3 vs. 2.9 ± 1.5; p = 0.054) but not R2 (4.0 ± 1.0 vs. 3.9 ± 1.1; p = 0.880). Dominant lesions showed significantly lower conspicuity using BLADE for R1 (2.8 ± 2.0 vs. 3.2 ± 2.0; p = 0.011) but not R2 (2.3 ± 1.6 vs. 2.4 ± 1.7; p = 0.353), and significantly lower tumor-to-peripheral-zone contrast using BLADE (0.35 ± 0.13 vs. 0.42 ± 0.15; p ≤ 0.001). R1 and R2 correctly localized four and three fewer dominant tumors, respectively, using BLADE than standard T2WI, although both correctly localized a similar fraction of dominant tumors using multi-parametric sequences. While R1 detected EPE in 10 of 11 patients using both sequences, R2 detected EPE in 3 more patients using BLADE.
CONCLUSION: BLADE may help reduce motion artifact of prostate T2WI and assist EPE detection, although at expense of reduced image contrast. In practice, BLADE may be useful in patients in whom initial T2WI is degraded by motion.