Does 16-detector computed tomography improve detection of non-traumatic subarachnoid hemorrhage in the Emergency Department?

J Emerg Med. 2009 Feb;36(2):171-5. doi: 10.1016/j.jemermed.2007.10.066. Epub 2008 Jun 24.


The diagnosis of subarachnoid hemorrhage remains difficult to establish, yet the sensitivity of increasingly available 16-detector computed tomography (CT) has not been evaluated. The objective of this study was to estimate the sensitivity of 16-detector CT for the diagnosis of non-traumatic subarachnoid hemorrhage in the Emergency Department (ED). A retrospective review was performed in an academic tertiary care hospital. Patients presenting to the ED from September 2003 through December 2004 with symptoms suggestive of subarachnoid hemorrhage and having a final diagnosis of non-traumatic subarachnoid hemorrhage were eligible for study. Diagnosis was established by positive 16-detector CT examination of the brain, or spinal fluid analysis. Patient demographics and results of CT, angiogram, and spinal fluid analysis were reviewed. Sensitivity of 16-detector CT was calculated by comparing CT results and cerebral angiogram results. Refined Wilson Simple Asymptotic 95% confidence intervals were calculated. Sixty-one consecutive patients met the study criteria and had a final diagnosis of non-traumatic subarachnoid hemorrhage. One of these patients did not have subarachnoid hemorrhage identified by 16-detector CT, but had a positive lumbar puncture and an aneurysm confirmed on cerebral angiography. Sensitivity of 16-detector CT for subarachnoid hemorrhage was 97% (95% confidence interval 84-100%). Sixteen-detector CT did not improve detection of non-traumatic subarachnoid hemorrhage when compared with studies using single-detector CT. If there is high clinical suspicion for non-traumatic subarachnoid hemorrhage and non-contrast 16-detector CT scan is negative, further evaluation is suggested.

Publication types

  • Evaluation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cerebral Angiography
  • Child
  • Emergency Service, Hospital*
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted
  • Male
  • Middle Aged
  • Retrospective Studies
  • Sensitivity and Specificity
  • Spinal Puncture
  • Subarachnoid Hemorrhage / diagnostic imaging*
  • Tomography, X-Ray Computed / methods*
  • Young Adult