title: Altered Mental Status in ICU Patients: Diagnostic Yield of Noncontrast Head CT for Abnormal and Communicable Findings.
abstract: OBJECTIVE
  To evaluate the diagnostic yield of noncontrast head CT for acute communicable findings in ICU patients specifically scanned for altered mental status.
  
  
  METHODS
  Retrospective observational cohort study.
  
  
  METHODS
  University Hospital Neuroscience, Medical, and Surgical ICUs.
  
  
  METHODS
  ICU patients with new-onset altered mental status.
  
  
  METHODS
  Noncontrast head CT.
  
  
  RESULTS
  Reports on head CTs from two university hospitals performed for the sole indication of altered mental status in ICU patients between July 2011 and June 2013 were reviewed for 1) acute (new or worsening) hemorrhage, 2) mass effect/herniation, 3) infarction, and 4) hydrocephalus. Subgroup analyses of positive findings were performed by 1) ICU group type, 2) age, and 3) race. A total of 2,486 head CTs were performed in 1,357 patients whose age ranged from 14 to 116 years (median, 59; mean, 57.6 ± 16). Acute communicable findings in at least one of four categories were present in 22.8% (566/2,486) of examinations, with hydrocephalus being most common (11.5% [286/2,486]). The frequency of any acute communicable findings in neuroscience, medical, and surgical ICUs was 28.6% (471/1,648), 9.8% (43/440), and 13.1% (52/398), respectively. Neuroscience ICU head CTs had significantly higher rates of acute communicable findings in all categories, except for acute infarction, compared with the other two ICUs (p < 0.001). Acute hydrocephalus (13.6% vs 7.4%; p < 0.001) and mass effect (6.7% vs 4.3%; p = 0.01) were more common in patients less than 65 years. For other acute categories, no significant difference was noted by age. There was no significant difference in the likelihood of a positive examination by race.
  
  
  CONCLUSIONS
  Almost one in four head CTs in a university ICU patient population performed for primary indication of altered mental status yields abnormal communicable findings. In this patient population, utilization management barriers to examination ordering should be minimized.
authors.affiliation: 1Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA.2Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI3Department of Radiology at Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Falgun H
authors.initials: FH
authors.lastname: Chokshi
authors.forename: Gelareh
authors.initials: G
authors.lastname: Sadigh
authors.forename: Walter
authors.initials: W
authors.lastname: Carpenter
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
authors.forename: Richard
authors.initials: R
authors.lastname: Duszak
authors.forename: Faisal
authors.initials: F
authors.lastname: Khosa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging; D003244:Consciousness Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult