Dynamic contrast-enhanced MRI of the prostate: An intraindividual assessment of the effect of temporal resolution on qualitative detection and quantitative analysis of histopathologically proven prostate cancer

Purpose: To assess the effects of temporal resolution (R_T) in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) on qualitative tumor detection and quantitative pharmacokinetic parameters in prostate cancer. Materials and Methods: This retrospective Institutional Review Board (IRB)-approved study included 58 men (64 ± 7 years). They underwent 3T prostate MRI showing dominant peripheral zone (PZ) tumors (24 with Gleason ≥ 4 + 3), prior to prostatectomy. Continuously acquired DCE utilizing GRASP (Golden-angle RAdial Sparse Parallel) was retrospectively reconstructed at R_T of 1.4 sec, 3.7 sec, 6.0 sec, 9.7 sec, and 14.9 sec. A reader placed volumes-of-interest on dominant tumors and benign PZ, generating quantitative pharmacokinetic parameters (k^trans, v_e) at each R_T. Two blinded readers assessed each R_T for lesion presence, location, conspicuity, and reader confidence on a 5-point scale. Data were assessed by mixed-model analysis of variance (ANOVA), generalized estimating equation (GEE), and receiver operating characteristic (ROC) analysis. Results: R_T did not affect sensitivity (R1_all: 69.0%–72.4%, all P_adj = 1.000; R1_{GS≥4 + 3}: 83.3–91.7%, all P_adj = 1.000; R2_all: 60.3–69.0%, all P_adj = 1.000; R2_{GS≥4 + 3}: 58.3%–79.2%, all P_adj = 1.000). R1 reported greater conspicuity of GS ≥ 4 + 3 tumors at R_T of 1.4 sec vs. 14.9 sec (4.29 ± 1.23 vs. 3.46 ± 1.44; P_adj = 0.029). No other tumor conspicuity pairwise comparison reached significance (R1_all: 2.98–3.43, all P_adj ≥ 0.205; R2_all: 2.57–3.19, all P_adj ≥ 0.059; R1_{GS≥4 + 3}: 3.46–4.29, all other P_adj ≥ 0.156; R2_{GS≥4 + 3}: 2.92–3.71, all P_adj ≥ 0.439). There was no effect of R_T on reader confidence (R1_all: 3.17–3.34, all P_adj = 1.000; R2_all: 2.83–3.19, all P_adj ≥ 0.801; R1_{GS≥4 + 3}: 3.79–4.21, all P_adj = 1.000; R2_{GS≥4 + 3}: 3.13–3.79, all P_adj = 1.000). k^trans and v_e of tumor and benign tissue did not differ across R_T (all adjusted P values [P_adj] = 1.000). R_T did not significantly affect area under the curve (AUC) of K^trans or v_e for differentiating tumor from benign (all P_adj = 1.000). Conclusion: Current PI-RADS recommendations for R_T of 10 seconds may be sufficient, with further reduction to the stated PI-RADS preference of R_T ≤ 7 seconds offering no benefit in tumor detection or quantitative analysis. Level of Evidence: 3. J. MAGN. RESON. IMAGING 2017;45:1464–1475.