Reliability of CT Angiography in Cerebral Vasospasm: A Systematic Review of the Literature and an Inter- and Intraobserver Study

Abstract

BACKGROUND AND PURPOSE: Computed tomography angiography offers a non-invasive alternative to DSA for the assessment of cerebral vasospasm following subarachnoid hemorrhage but there is limited evidence regarding its reliability. Our aim was to perform a systematic review (Part I) and to assess (Part II) the inter-and intraobserver reliability of CTA in the diagnosis of cerebral vasospasm. MATERIALS AND METHODS:In Part I, articles reporting the reliability of CTA up to May 2018 were systematically searched and evaluated. In Part II, 11 raters independently graded 17 arterial segments in each of 50 patients with SAH for the presence of vasospasm using a 4-category scale. Raters were additionally asked to judge the presence of any moderate/severe vasospasm ($ 50% narrowing) and whether findings would justify augmentation of medical treatment or conventional angiography 6 balloon angioplasty. Four raters took part in the intraobserver reliability study. RESULTS:In Part I, the systematic review revealed few studies with heterogeneous vasospasm definitions. In Part II, we found interrater reliability to be moderate at best (k # 0.6), even when results were stratified according to specialty and experience. Intrarater reliability was substantial (k . 0.6) in 3/4 readers. In the per arterial segment analysis, substantial agreement was reached only for the middle cerebral arteries, and only when senior raters' judgments were dichotomized (presence or absence of $50% narrowing). Agreement on the medical or angiographic management of vasospasm based on CTA alone was less than substantial (k # 0.6). CONCLUSIONS:The diagnosis of vasospasm using CTA alone was not sufficiently repeatable among observers to support its general use to guide decisions in the clinical management of patients with SAH.

Standardized Classification of Cerebral Vasospasm after Subarachnoid Hemorrhage by Digital Subtraction Angiography

“…Still, there is also limited evidence regarding its reliability. Letourneau-Guillon et al [ 21 ] assessed the inter- and intraobserver reliability of CTA in diagnosing cerebral vasospasm in the literature. In the analyzed 14 studies, eight different classification schemes were used with three to five categories and various arbitrary cutoffs.…”

“…The interobserver agreement ranged from 66% to 79%. In their approach, Letourneau-Guillon et al [ 21 ] asked eleven clinicians to grade the degree of vasospasm of 17 arterial segments on a 4-category scale with the initial CTA. There were three additional questions (yes/no): (1) Is there moderate-severe vasospasm at any location?…”

“…Pharmacological agents can be evaluated according to their vasodilating potential for different vessel segments. A moderate reproducibility of 68.4% is an argument against the new grading system, but further non-automated classifications could not show higher agreements without initial training [ 21 , 22 ]. In this context, we offer a scheme of visual cerebral vasospasm classification for further development.…”

Reliability of the Diagnosis of Cerebral Vasospasm Using Catheter Cerebral Angiography: A Systematic Review and Inter- and Intraobserver Study

“…Our findings have a number of important implications for vasospasm research. Correlative research on alternative (noninvasive) diagnostic tests such as transcranial Doppler, 13 CTA, 10,17,18 or MRA 18 that commonly use conventional angiography as the comparative benchmark examination should bear in mind the suboptimal reliability of the gold standard diagnostic test. All by itself, the lack of reliability of the diagnoses may explain how pharmacologic treatments such as nimodipine could be shown to be clinically effective despite the lack of a measurable effect on angiographic vessel narrowing; 19 this explanation further reinforces the notion that hard clinical outcomes should be selected for clinical trials on vasospasm.…”

Interleukin-6 in Cerebrospinal Fluid Small Extracellular Vesicles as a Potential Biomarker for Prognosis of Aneurysmal Subarachnoid Haemorrhage

“…27 Cerebral vasospasm was diagnosed using computed tomography angiography, digital subtraction angiography, magnetic resonance angiography, or transcranial Doppler according to maximum mean flow velocity (MMFV) > 120 cm/s, and Lindegaard ratios > 3. [28][29][30] Hydrocephalus and DCI were classified as present or absent based on CT scans or magnetic resonance imaging (MRI). DCI was confirmed as a new focal neurological deficit, consciousness disorder, or a new infarct based on CT scans or MRI.…”