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. Author manuscript; available in PMC: 2021 Mar 22.
Published in final edited form as: AJR Am J Roentgenol. 2018 May 7;211(1):W33–W41. doi: 10.2214/AJR.17.18702

TABLE 4:

Univariate and Multivariate Analysis for Prostate Imaging Reporting and Data System Version 2 DWI Category 4 or 5 Classification by the Expert Reader

Metric ROC Analysis AUC Prediction Performance for Score Classification 1–3 Versus 4 and 5
Optimal Cutoffa Sensitivity at Cutoff Specificity at Cutoff PPV at Cutoff
Whole prostate
 Mean ADC 0.87 (0.82–0.92) < 1061 (1074–950) 0.88 (0.73–0.95) 0.72 (0.64–0.89) 0.83 (0.77–0.93)
 Normalized ADC 0.82 (0.76–0.88) < 0.65 (0.74–0.58) 0.72 (0.62–0.96) 0.79 (0.53–0.90) 0.84 (0.74–0.92)
 Area 0.65 (0.56–0.73) ≥ 0.54 (0.20–0.90) 0.37 (0.23–0.82) 0.87 (0.44–0.97) 0.81 (0.66–0.95)
 Mean ADC and area 0.91 (0.87–0.94) ≥ 0.72 (0.50–0.80) 0.78 (0.68–0.91) 0.91 (0.77–0.98) 0.93 (0.85–0.99)
 Normalized ADC and area 0.86 (0.81–0.90) ≥ 0.63 (0.48–0.81) 0.76 (0.60–0.87) 0.82 (0.72–0.98) 0.87 (0.80–0.98)
Peripheral zone
 Mean ADC 0.87 (0.81–0.92) ≤ 1045 (1074–910) 0.87 (0.61–0.97) 0.71 (0.61–0.96) 0.78 (0.70–0.95)
 Normalized ADC 0.82 (0.75–0.88) ≤ 0.65 (0.72–0.56) 0.77 (0.59–0.93) 0.75 (0.59–0.94) 0.78 (0.68–0.93)
 Area 0.60 (0.50–0.70) ≥ 0.70 (0.20–1.10) 0.23 (0.13–0.81) 0.94 (0.39–1.00) 0.82 (0.55–1.00)
 Mean ADC and area 0.91 (0.83–0.94) ≥ 0.71 (0.39–0.80) 0.69 (0.61–0.92) 0.94 (0.73–1.00) 0.93 (0.77–1.00)
 Normalized ADC and area 0.84 (0.77–0.90) ≥ 0.69 (0.40–0.77) 0.67 (0.59–0.90) 0.90 (0.69–0.98) 0.89 (0.73–0.97)
Transition zone
 Mean ADC 0.89 (0.80–0.97) ≤ 1024 (1068–896) 0.86 (0.57–0.98) 0.81 (0.67–1.00) 0.93 (0.86–1.00)
 Normalized ADC 0.86 (0.74–0.96) ≤ 0.64 (0.76–0.57) 0.70 (0.56–1.00) 0.88 (0.52–1.00) 0.94 (0.81–1.00)
 Area 0.66 (0.50–0.80) ≥ 0.90 (0.30–1.20) 0.40 (0.26–0.91) 0.94 (0.43–1.00) 0.94 (0.78–1.00)
 Mean ADC and area 0.93 (0.86–0.99) ≥ 0.77 (0.55–0.91) 0.84 (0.68–0.98) 0.94 (0.78–1.00) 0.97 (0.91–1.00)
 Normalized ADC and area 0.89 (0.80–0.97) ≥ 0.76 (0.37–0.92) 0.79 (0.57–1.00) 0.81 (0.67–1.00) 0.92 (0.86–1.00)

Note—Values in parentheses are 95% CI. ADC = apparent diffusion coefficient. Mean ADC is measured in square micrometers per second.

a

With use of the optimal cutoffs, the sensitivity, specificity, and positive predictive value (PPV) shown can be achieved. Univariate cutoffs refer to actual value of the variable; bivariate cutoffs refer to risk calculated with the given logistic regression model.