Article Figures & Data
Figures
- Fig 1.
ADC map and histogram of primary NPC before treatment in a 50-year-old woman with local failure. The histogram shows that the greatest frequency of ADC values is shifted toward the central ADC range (ADC skewness = 0.11) and the peak is broadened (ADC kurtosis = 3.89).
- Fig 2.
ADC map and histogram of primary NPC before treatment in a 43-year-old man with local control. The histogram shows that the greatest frequency of ADC values is shifted toward the lower ADC range (ADC skewness = 1.42) and the peak is more acute (ADC kurtosis = 8.77).
- Fig 3.
Side-by-side boxplots of ADC skewness comparing local control and local failure.
- Fig 4.
ROC analysis curve for ADC skewness.
Tables
- Table 1:
ADC parameters, volume, and T-stage of the primary tumor and the patient age for prediction of treatment response
Parameter Whole Group (N = 158) (Mean) Local Failure (n = 27) (Mean) Local Control (n = 131) (Mean) Student t Test (P Value) Univariate Logistic Regression P Value Odds Ratio (95% CI) ADC mean (×10−3 mm2/s) 0.91 ± 0.11 0.90 ± 0.12 0.91 ± 0.11 .879 .878 0.75 (0.02–29.45) ADC skewness 0.68 ± 0.47 0.45 ± 0.40 0.72 ± 0.47 .006a .007a 0.22 (0.08–0.67) ADC kurtosis 4.93 ± 1.87 4.19 ± 1.29 5.08 ± 1.94 .024a .024a 0.65 (0.44–0.95) Primary tumor volume (mL) 24.63 ± 17.99 28.20 ± 17.90 23.89 ± 17.99 .256 .298 1.011 (0.99–1.03) T-stage T1, T2 74 12 62 NA .785 1.123 (0.49–2.58) T3, T4 84 15 69 Patient age (yr) 50.19 ± 10.34 49.74 ± 11.34 50.28 ± 10.17 .805 .804 1.00 (0.96–1.04) Note:—NA indicates not applicable.
↵a Statistically significant.
Parameter ADC Skewness Threshold ≤0.55 P value .0001 Area under the ROC curve 0.68 True-positive 21 False-positive 49 True-negative 82 False-negative 6 Sensitivity 78% Specificity 63% Accuracy 65% Positive predictive value 30% Negative predictive value 93%
