Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study

Abstract

Objective To measure the sensitivity of modern third generation computed tomography in emergency patients being evaluated for possible subarachnoid haemorrhage, especially when carried out within six hours of headache onset.Design Prospective cohort study.Setting 11 tertiary care emergency departments across Canada, 2000-9.Participants Neurologically intact adults with a new acute headache peaking in intensity within one hour of onset in whom a computed tomography was ordered by the treating physician to rule out subarachnoid haemorrhage.Main outcome measures Subarachnoid haemorrhage was defined by any of subarachnoid blood on computed tomography, xanthochromia in cerebrospinal fluid, or any red blood cells in final tube of cerebrospinal fluid collected with positive results on cerebral angiography. ResultsOf the 3132 patients enrolled (mean age 45.1, 2571 (82.1%) with worst headache ever), 240 had subarachnoid haemorrhage (7.7%). The sensitivity of computed tomography overall for subarachnoid haemorrhage was 92.9% (95% confidence interval 89.0% to 95.5%), the specificity was 100% (99.9% to 100%), the negative predictive value was 99.4% (99.1% to 99.6%), and the positive predictive value was 100% (98.3% to 100%). For the 953 patients scanned within six hours of headache onset, all 121 patients with subarachnoid haemorrhage were identified by computed tomography, yielding a sensitivity of 100% (97.0% to 100.0%), specificity of 100% (99.5% to 100%), negative predictive value of 100% (99.5% to 100%), and positive predictive value of 100% (96.9% to 100%). ConclusionModern third generation computed tomography is extremely sensitive in identifying subarachnoid haemorrhage when it is carried out within six hours of headache onset and interpreted by a qualified radiologist.

Can the combination of a negative computed tomography result and a negative lumbar puncture safely exclude the diagnosis of subarachnoid hemorrhage in patients with thunderclap headache?

“…For the 953 patients scanned within 6 hours of headache onset, all 121 patients with SAH were identified by CT, yielding a sensitivity of 100% (97.0-100.0%) and a specificity of 100% (99.5-100%). 18 This is consistent with the findings of Boesiger and Shiber mentioned previously. 15 …”

“…18 A total of 3,132 patients were prospectively enrolled from 11 Canadian tertiary care EDs who presented with new-onset acute (thunderclap) headache. For the 953 patients scanned within 6 hours of headache onset, all 121 patients with SAH were identified by CT, yielding a sensitivity of 100% (97.0-100.0%) and a specificity of 100% (99.5-100%).…”

Critical Analysis of an e-Learning and Interactive Teaching Module with Respect to the Interpretation of Emergency Computed Tomography of the Brain

“…Another pathology for which a significant increase in sensitivity in the interactive teaching group (91 % vs. 61 %) as well as the e-learning group (82 % vs. 61 %, control group, respectively) could be found was subarachnoid hemorrhage. When scans are interpreted by a neuroradiologist or qualified general radiologist, ▶ a sensitivity of up to 100 % for the detection of subarachnoid hemorrhage is reported in other studies [14,15]. An increase in sensitivity for subdural hematoma and skull fracture could be observed for both the interactive teaching group and the e-learning group, but only the e-learning group revealed a significant difference.…”

Clinical and imaging factors associated with severe complications of cervical necrotizing fasciitis

“…Celles-ci incluent les polytraumatisés [11], le diagnostic d'hémorragie méningée [12], et de pancréatite aigüe [13], où le scanner réalisé immédiatement après l'admission en urgence aide et guide les traitements médicaux et chirurgicaux. Le scanner cervical fait déjà partie de la prise en charge standard des FNC [9,14].…”