title: Impact of adaptive statistical iterative reconstruction on radiation dose in evaluation of trauma patients.
abstract: BACKGROUND
  A recent study showed that computed tomographic (CT) scans contributed 93% of radiation exposure of 177 patients admitted to our Level I trauma center. Adaptive statistical iterative reconstruction (ASIR) is an algorithm that reduces the noise level in reconstructed images and therefore allows the use of less ionizing radiation during CT scans without significantly affecting image quality. ASIR was instituted on all CT scans performed on trauma patients in June 2009. Our objective was to determine if implementation of ASIR reduced radiation dose without compromising patient outcomes.
  
  
  METHODS
  We identified 300 patients activating the trauma system before and after the implementation of ASIR imaging. After applying inclusion criteria, 245 charts were reviewed. Baseline demographics, presenting characteristics, number of delayed diagnoses, and missed injuries were recorded. The postexamination volume CT dose index (CTDIvol) and dose-length product (DLP) reported by the scanner for CT scans of the chest, abdomen, and pelvis and CT scans of the brain and cervical spine were recorded. Subjective image quality was compared between the two groups.
  
  
  RESULTS
  For CT scans of the chest, abdomen, and pelvis, the mean CTDIvol (17.1 mGy vs. 14.2 mGy; p < 0.001) and DLP (1,165 mGy·cm vs. 1,004 mGy·cm; p < 0.001) was lower for studies performed with ASIR. For CT scans of the brain and cervical spine, the mean CTDIvol (61.7 mGy vs. 49.6 mGy; p < 0.001) and DLP (1,327 mGy·cm vs. 1,067 mGy·cm; p < 0.001) was lower for studies performed with ASIR. There was no subjective difference in image quality between ASIR and non-ASIR scans. All CT scans were deemed of good or excellent image quality. There were no delayed diagnoses or missed injuries related to CT scanning identified in either group.
  
  
  CONCLUSIONS
  Implementation of ASIR imaging for CT scans performed on trauma patients led to a nearly 20% reduction in ionizing radiation without compromising outcomes or image quality.
  
  
  METHODS
  Therapeutic study, level IV.
authors.affiliation: Departments of Surgery and Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Maxfield
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Schuster
authors.forename: Edward A
authors.initials: EA
authors.lastname: McGillicuddy
authors.forename: Calvin J
authors.initials: CJ
authors.lastname: Young
authors.forename: Monica
authors.initials: M
authors.lastname: Ghita
authors.forename: S A Jamal
authors.initials: SA
authors.lastname: Bokhari
authors.forename: Isabel B
authors.initials: IB
authors.lastname: Oliva
authors.forename: James A
authors.initials: JA
authors.lastname: Brink
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Davis
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000379:methods; D013902:Radiography, Thoracic / Q000379:methods; D012189:Retrospective Studies; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards; D014193:Trauma Centers; D014947:Wounds and Injuries / Q000000981:diagnostic imaging*