CTA Supplemented by CTP Increases Interrater Reliability and Endovascular Treatment Use in Patients with Aneurysmal SAH

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FIG 1.
The interrater reliability of first and second ratings (Krippendorff α) is stratified by vessel segments. Vasospasm was graded on CTA using a tripartite scale for each vessel separately. The scale included no vasospasm, mild vasospasm <50%, and severe vasospasm >50%. Krippendorff α values are displayed by black triangles and blue squares for the first and second ratings, respectively. The black and blue lines indicate the 95% CIs.
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FIG 2.
Illustrative case of a patient without left-hemispheric vasospasm on follow-up imaging. The ICA, A1, and A2 segments of the ACA as well as the M1 and M2 segments of the MCA are highlighted in color. The color graduation indicates the interrater reliability (Krippendorff α) for the first rating. The graduation ranges from slight (α = .0) to substantial (α = .8) agreement. Note that proximal segments accounted for higher interrater reliability except for the ICA.

Table 1:

Patient baseline, procedural, and outcome characteristics

Patient Characteristics (n = 46)
Age (mean)	56.6 (SD, 12.6)
Female sex (No.) (%)	33 (71.7)
Hunt and Hess (median) (IQR)	3 (2–4)
Modified Fisher scale (median) (IQR)	4 (3–4)
Intracerebral hemorrhage (No.) (%)	23 (50.0)
Hypertension (No.) (%)	29 (63.0)
Smoker (No.) (%)	17 (37.0)
Aneurysm characteristics
Ruptured aneurysm location
ICA (No.) (%)	16 (34.8)
MCA (No.) (%)	5 (10.9)
ACA (No.) (%)	17 (37.0)
Posterior circulation (No.) (%)	8 (17.4)
Aneurysm size (median) (IQR) (mm)	6.5 (5–8.25)
Patients with multiple aneurysms (No.) (%)	3 (6.5)
Treatment characteristics
Clip (No.) (%)	8 (17.4)
Endovascular treatment (No.) (%)	38 (82.6)
EVD placement (No.) (%)	36 (78.3)
Patients with 2 instances of vasospasm (No.) (%)	25 (54.3)

Table 2:

Reasons to perform follow-up CT examination (n = 71)

Reasons
Only neurologic deterioration (eg, reduced level of consciousness or new focal deficit) (No.) (%)	30/71 (42.3)
Only elevated TCD profiles (No.) (%)	17/71 (23.9)
Neurologic deterioration and elevated TCD profiles (No.) (%)	19/71 (26.8)
Decreased P_btO_2, (No.) (%)	1/71 (1.4)
Screening CT (comatose patients without TCD acoustic window) (No.) (%)	4/71 (5.6)

Table 3:

Interrater reliability and agreement for the graduation of vasospasm on CT^{^a}

Note:—PCA indicates posterior cerebral artery.
↵a Vasospasm was graded using a tripartite scale for each vessel separately. The scale included no vasospasm, mild vasospasm <50%, and severe vasospasm >50%. Interrater reliability was calculated using the Krippendorff α.

Table 4:

Interrater reliability and agreement regarding graduation and treatment decisions of vasospasm on CT

	Interrater Reliability and Agreement^{^a}
	All Raters (n = 3)		Senior (n = 2)
	Agreement (%)	Interrater Reliability κ (95% CI)	Agreement (%)	Interrater Reliability κ (95% CI)
First rating (CTA)
Detection of severe vasospasm in any arterial segment (>50% narrowing)	63	0.27 (0.11–0.42)	61	0.28 (0.10–0.46)
Endovascular treatment?	62	0.23 (0.06–0.39)	61	0.23 (−0.01–0.46)
Second rating (CTA + CTP)
Detection of severe vasospasm in any arterial segment (>50% narrowing)	65	0.31 (0.15–0.46)	73	0.46 (0.26–0.66)
Endovascular treatment?	75	0.47 (0.30–0.64)	89	0.73 (0.55–0.91)
Perfusion deficit?	92	0.77 (0.63–0.91)	93	0.82 (0.66–0.97)