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Abstract Background The Restriction Spectrum Imaging restriction score (RSIrs) has demonstrated higher diagnostic accuracy for clinically significant prostate cancer (csPCa) than conventional DWI. Both diffusion and T 2 properties of prostate tissue inform the RSI signal, and studies have shown that each may be valuable for csPCa discrimination. Purpose To determine whether prostate T 2 varies across RSI compartments and in the presence of csPCa, and to evaluate whether consideration of compartmental T 2 (c T 2 ) improves csPCa detection over RSIrs alone. Study Type Retrospective. Population Two cohorts (46 and 195 patients) scanned for csPCa. Field Strength/Sequence 3T multi- b -value DWI acquired at multiple TEs. Assessment c T 2 values were computed from multi-TE RSI data and compared between RSI model compartments. csPCa detection was compared between RSIrs and a logistic regression model (LRM) for predicting the probability of csPCa using c T 2 in combination with RSI measurements. Statistical Tests T wo-sample t-tests (α=0.05) were used to compare c T 2 values between compartments and between patients with and without csPCa. Area under the receiver operating characteristic curve (AUC) was used to evaluate csPCa detection performance. Results In both cohorts, T 2 differed ( p <0.05) across all RSI compartments ( C 1, C 2, C 3, C 4 ). Voxel-level data from cohort 1 showed that T 2 differed between normal and cancerous tissue in C 1, C 2, C 3 ( p <0.001). Whole-prostate T 2 differed between patients with and without csPCa in C 3 ( p =0.02). In cohort 2, whole-prostate T 2 differed in C 1 ( p =0.01), C 3 ( p =0.01), and C 4 ( p <0.01). Consideration of c T 2 improved csPCa discrimination compared to diffusion alone, but not compared to RSIrs cohort 1: 0.80 vs 0.70 (diffusion) and 0.80 (RSIrs), cohort 2: 0.72 vs 0.65 (diffusion) and 0.72 (RSIrs). Data Conclusion Significant differences in c T 2 were observed between normal and cancerous prostatic tissue. With our data, however, consideration of c T 2 did not significantly improve cancer detection performance over RSIrs alone.
Domingo et al. (Sat,) studied this question.