Enrico Martin

122 Chapter 6 Figure 2 SROC’s of MRI characteristics Seven studies studied the use of absence of target sign, a classic sign in neurogenic tumors on T2-weighted imaging referring to a high signal intensity ring peripherally surrounding an area of low signal intensity centrally. 16,30,32,35,38–40 Pooled sensitivity and specificity were 0.99 (95% CI: 0.94-1.00) and 0.33 (95% CI: 0.15-0.54) respectively. Pooled pLR was 1.51 (1.13-2.25) and nLR was 0.04 (0.00-0.30). There was substantial heterogeneity between studies. Sensitivity was higher in studies with smaller amount of lesions, higher proportion of MPNSTs, including symptomatic lesions only, and histologically proven lesions only. Sensitivity was lower in those including NF1 patients only. Specificity was higher in studies including NF1 patients only.