Table 2

Clinical relevance: positive predictive values from selected large cohort studies

Study/rule	TP	FP	FN	TN	PPV (%)	Scans/ICI identified
PECARN	269	12962	9	18454	2.0	49.2
Da Dalt	22	478	0	3298	4.4	22.7
CHALICE	164	2853	4	19558	5.4	18.4
CATCH	167	1802	3	1809	8.5	11.8
UCD	105	1111	0	827	8.6	11.6
NEXUS II18	136	1298	2	230	9.4	10.5
Infants
PECARN	97	4916	1	5704	1.9	51.7
Oman	25	269	0	15	8.5	11.8
UCD	15	119	0	60	11.2	8.9
NSI
PECARN2 –18	11	2600	0	3800	0.4	237.4
CATCH	26	1111	0	2643	2.2	43.7
UCD	29	719	0	1295	3.9	25.7
CHALICE	134	3076	3	19559	4.2	23.9
PECARN (<2)	5	1035	0	1176	0.5	208

FN, false negative; FP, false positive; ICI, intracranial injury; NSI, neurosurgical intervention (variable definitions for each study – see table 1); PPV, positive predictive value; TN, true negative; TP, true positive.