Table 2.

Comparison of ultrasound penetrativity grouped by thickness

Group	Impenetrable temporal window (n = 133)	Penetrable temporal window (n = 168)	χ 2	P
Thickness ≥ 1.045 cm	111(86.0%)	18(14.0%)	160.401	< 0.001
Thickness < 1.045 cm	22(12.8%)	150(87.2%)

Note: The area under the ROC curve (AUC) for skull thickness was 0.887 (cutoff value 1.045 cm). Impenetrable was defined as no signal being detected from any of the cerebral arteries. Penetrable was defined as successful display of any one of the cerebral arteries