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. 2025 Feb 4:5:104200.
doi: 10.1016/j.bas.2025.104200. eCollection 2025.

Diagnosis of subarachnoid haemorrhage: Systematic evaluation of CT head diagnostic accuracy and comparison with the 2022 NICE guidelines

Conor S Gillespie  1   2   3 , John Gerrard Hanrahan  4   5 , Roxana Mahdiyar  1   6 , Keng Siang Lee  7 , Mohammad Ashraf  8 , Ali M Alam  9 , Justyna O Ekert  1   2 , Orla Mantle  1   2 , Simon C Williams  5   10 , Jonathan P Funnell  5   10 , Nihal Gurusinghe  11 , Raghu Vindlacheruvu  12 , Peter C Whitfield  13 , Rikin A Trivedi  1   2 , Adel Helmy  1   2 , Peter J Hutchinson  1   2   12
Affiliations

Diagnosis of subarachnoid haemorrhage: Systematic evaluation of CT head diagnostic accuracy and comparison with the 2022 NICE guidelines

Conor S Gillespie et al. Brain Spine. .

Abstract

Introduction: Aneurysmal subarachnoid haemorrhage has a high incidence, and morbidity. It has been suggested that a negative non-contrast CT head can rule out SAH if performed within 6 h of symptom onset.

Research question: What is the sensitivity of CT head at ruling out SAH stratified by time-point, and what is the potential impact of omitting Lumbar Puncture (LP) from the diagnostic pathway?

Material and methods: Systematic review and meta-analysis (PROSPEROID CRD42022379929). Three databases were searched, and articles published between January 2000-May 2022 included (Search date 27th November 2022). Primary objective was diagnostic accuracy of CT scans for detecting SAH at <6 h from symptom onset, including reported sensitivity, and specificity values.

Results: 63 articles were included (38,237 patients, 7673 with SAH). Pooled CT head sensitivity was 0.94 for excluding SAH (22 studies, 95% Confidence Interval [CI] 0.90-0.97). At <6 h, CT head sensitivity was 0.995 (6 studies, 95% CI 0.941-1.000). Most studies (57.1%, n = 36/63) were classified as high risk of bias. If LP was removed from the diagnostic pathway in the UK, assuming an incidence of 4800 SAH per-year, 336 SAH would be missed per-year, 24 per-year if LP was removed for negative CT < 6 h (95% CI 0-278) and 58 per-year if mean sensitivity is used (95% CI 0-240).

Discussion and conclusion: CT head appears to be highly sensitive at excluding SAH <6 h from symptom onset. High quality, prospective data is required to further established the utility of early (<6 h) negative CT head. We recommend that if there is strong clinical suspicion of SAH, yet CT head is reported negative <6 h of symptom onset, that a LP be performed.

Keywords: 6 h; CT; Computed tomography; LP; Lumbar puncture; Subarachnoid haemorrhage.

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Conflict of interest statement

PW is the current president of the Society of British Neurological Surgeons (SBNS). NG is the current NICE coordinator for the SBNS. RV is the current Chair of the British Neurovascular Group (BNVG). PH is Meetings and Communications Secretary of the SBNS. PJH, AEH, RATR are council members of the SBNS.

Figures

Fig. 1
Fig. 1
PRISMA Flow diagram, of study selection for inclusion in this review and meta-analysis.
Fig. 2
Fig. 2
Sensitivity forest plot for CT head at any time point.
Fig. 3
Fig. 3
Pooled forest plot for CT head at <6 h of symptom onset.
See this image and copyright information in PMC

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