Table 4:

Critical test results for emergency department CT examinations performed at Hamilton Health Sciences, by diagnosis

CT type	Critical test result	No. of results (95% CI); study period
		Before pandemic (95% CI)	During pandemic (95% CI)	p value
CT examination of the head	Brain infarction	20 (12–31)	17 (10–27)	0.6
	Intracranial hemorrhage	27 (18–39)	18 (11–28)	0.2
	Sinusitis, mastoiditis or orbital cellulitis	22 (14–33)	4 (1–10)	0.002
CT angiogram of the head and neck	Carotid or vertebral occlusion or > 70% stenosis	8 (3–16)	7 (3–14)	0.8
	Intracranial arterial thromboembolism	1 (0–6)	5 (2–12)	0.1
	Dural venous sinus thrombus	2 (0–7)	0 (0–4)	1.0
CT pulmonary angiogram	Pulmonary embolism	21 (13–32)	12 (6–21)	0.1
CT examination of the abdomen and pelvis	Appendicitis	8* (3–16)	11† (5–20)	0.5
	Diverticulitis	24‡ (15–36)	22§ (14–33)	0.8
	Bowel obstruction	8 (3–16)	13 (7–22)	0.3
	Ureteric calculi	2 (0–7)	11 (5–20)	0.03
	Acute aortic syndrome	0 (0–4)	0 (0–4)	NA

Note: CI = confidence interval, CT = computed tomography, NA = not applicable.

^*Two complicated by pneumoperitoneum and 1 by abscess.

^†Two complicated by pneumoperitoneum and 1 by pneumoperitoneum with phlegmon.

^‡Two complicated by abscess, 2 by phlegmon and 2 by pneumoperitoneum.

^§Four complicated by abscess and 1 by pneumoperitoneum.