title: Repeated head CT in the neurosurgical intensive care unit: feasibility of sinogram-affirmed iterative reconstruction-based ultra-low-dose CT for surveillance.
abstract: OBJECTIVE
  Patients in the neurosurgical intensive care unit undergo multiple head CT scans, resulting in high cumulative radiation exposures. Our aim was to assess the acceptability of a dedicated, special-purpose sinogram-affirmed iterative reconstruction-based ultra-low-dose CT protocol for neurosurgical intensive care unit surveillance head CT examinations, comparing image quality with studies performed with our standard-of-care sinogram-affirmed iterative reconstruction low-dose CT and legacy filtered back-projection standard-dose CT protocols.
  
  
  METHODS
  A retrospective analysis was performed of 54 head CT examinations: ultra-low-dose CT (n = 22), low-dose CT (n = 12), and standard-dose CT (n = 20) in 22 patients in the neurosurgical intensive care unit. Standard-dose CT was reconstructed by using filtered back-projection on a Somatom Sensation 64 scanner. Ultra-low-dose CT and ultra-low-dose CT examinations were performed on a Siemens AS+128 scanner with commercially available sinogram-affirmed iterative reconstruction. Qualitative and quantitative parameters, including image quality and dose, were evaluated.
  
  
  RESULTS
  Sinogram-affirmed iterative reconstruction ultra-low-dose CT represented a 68% lower dose index volume compared with filtered back-projection standard-dose CT techniques in the same patients while maintaining similar quality and SNR levels. Sinogram-affirmed iterative reconstruction low-dose CT offered higher image quality than filtered back-projection standard-dose CT (P < .05) with no differences in SNR at a 24% lower dose index volume. Compared with low-dose CT, ultra-low-dose CT had significantly lower SNR (P = .001) but demonstrated clinically satisfactory measures of image quality.
  
  
  CONCLUSIONS
  In this cohort of patients in the neurosurgical intensive care unit, dedicated ultra-low-dose CT for surveillance head CT imaging led to a significant dose reduction while maintaining adequate image quality.
authors.affiliation: From the Department of Neuroradiology, The Mount Sinai Medical Center, New York, New York.
authors.forename: I
authors.initials: I
authors.lastname: Corcuera-Solano
authors.affiliation: From the Department of Neuroradiology, The Mount Sinai Medical Center, New York, New York.
authors.forename: A H
authors.initials: AH
authors.lastname: Doshi
authors.affiliation: From the Department of Neuroradiology, The Mount Sinai Medical Center, New York, New York.
authors.forename: A
authors.initials: A
authors.lastname: Noor
authors.affiliation: From the Department of Neuroradiology, The Mount Sinai Medical Center, New York, New York. nuromri@gmail.com.
authors.forename: L N
authors.initials: LN
authors.lastname: Tanenbaum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009493:Neurosurgery; D015588:Observer Variation; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011874:Radiometry; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods*