TABLE 2:

Threshold values for Cho/Cr ratio for differentiation between low- and high-grade gliomas

Description	Cho/Cr	Sensitivity	Specificity	PPV	NPV	C2 Error	C1 Error
Minimum C2 Error*	1.08	97.5	12.5	77.0	62.5	23.8	45.0
Minimum C1 Error†	1.56	75.8	47.5	81.2	39.6	31.3	38.3
Same sensitivity as cMRI	1.61	72.5	50.0	81.3	37.7	33.1	38.8
Same specificity as cMRI	1.88	55.0	65.0	83.5	33.3	41.9	38.8

Note.—Conventional MR imaging (cMRI) sensitivity 72.5%, specificity 65.0%, PPV 86.1%, NPV 44.1%, C2 error 29.4%, and C1 error 31.8%.

^*C2 = the percentage of observed data points misclassified.

^†C1 = 1 − (sensitivity + specificity)/2. This maximizes the average of sensitivity and specificity.