title: Added Value of MRI over CT of the Brain in Intensive Care Unit Patients.
abstract: BACKGROUND
  Intensive care unit (ICU) patients with neurological impairments often require neuroimaging. However, the relative sensitivity of various imaging modalities of the brain has not yet been explored in this population.
  
  
  METHODS
  In this study, we compare the findings of CT and MRI scans in ICU patients to (1) identify the number and rate of clinically relevant lesion detected by MRI while missed by CT and vice versa and (2) determine specific lesion types for which CT versus MRI discrepancies exist. A review of medical records included CT and MRI reports of patients who underwent these procedures while they were patients in our ICUs between July 2004 and July 2009. MRI and CT were compared regarding their ability to detect clinically relevant abnormalities. Odds ratios with 95% confidence limits were calculated to compare diagnostic categories regarding the rate of discrepant MRI versus CT findings, followed by power analyses to estimate sample sizes necessary to allow for further testing in a larger trial.
  
  
  RESULTS
  MRI revealed clinically relevant additional abnormalities over CT in 129 of 136 patients (95%) that included the detection of additional finding for 15/27 hemorrhagic lesions (55.6%), 33/36 (92%) ischemic strokes, 19/27 (70%) traumatic lesions, 8/14 (57%) infections, 15/24 (62.5%) metabolic abnormalities, and all seven neoplasms. Odds ratio analysis revealed the added sensitivity of MRI to be greater for ischemic and neoplastic lesions than for trauma, metabolic-related abnormalities, infection, or hemorrhage.
  
  
  CONCLUSIONS
  MRI is more sensitive than CT in identifying clinically meaningful lesions in at least a subset of ICU patients, regardless of pathology.
authors.affiliation: 1Anesthesia and Critical Care Department, Faculty of Medicine,King Abdulaziz University,King Abdulaziz University Hospital,Jeddah,Saudi Arabia.
authors.forename: Haifa M
authors.initials: HM
authors.lastname: Algethamy
authors.affiliation: 2Department of Clinical Neurological Sciences,Riyadh Military Hospital,Riyadh,Saudi Arabia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Alzawahmah
authors.affiliation: 3Department of Clinical Neurological Sciences,Medical Biophysics,Medical Imaging,and Psychology,London Health Sciences Centre,Western University,London,Ontario,Canada.
authors.forename: G Bryan
authors.initials: GB
authors.lastname: Young
authors.affiliation: 3Department of Clinical Neurological Sciences,Medical Biophysics,Medical Imaging,and Psychology,London Health Sciences Centre,Western University,London,Ontario,Canada.
authors.forename: Seyed M
authors.initials: SM
authors.lastname: Mirsattari
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007362:Intensive Care Units; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000175:diagnosis* / Q000628:therapy*; D016017:Odds Ratio; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Central nervous system pathology; computed tomography; intensive care unit patients; magnetic resonance imaging; prognosis; unresponsive patients