title: Reducing Radiation Dose in Adult Head CT using Iterative Reconstruction - A Clinical Study in 177 Patients.
abstract: OBJECTIVE
  To assess how ASIR (adaptive statistical iterative reconstruction) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT).
  
  
  METHODS
  Non-contrast emergency CT scans of the head acquired in 177 patients were evaluated. The scans were acquired and processed using four different protocols: Group A (control): 120 kV, FBP (filtered back projection) n = 71; group B1: 120 kV, scan and reconstruction performed with 20 % ASIR (blending of 20 % ASIR and 80 % FBP), n = 86; group B2: raw data from group B1 reconstructed using a blending of 40 % ASIR and 60 % FBP, n = 74; group C1: 120 kV, scan and reconstruction performed with 30 % ASIR, n = 20; group C2: raw data from group C1 reconstructed using a blending of 50 % ASIR and 50 % FBP, n = 20. The effective dose was calculated. Image quality was assessed quantitatively and qualitatively.
  
  
  RESULTS
  Compared to group A, groups B1/2 and C1/2 showed a significantly reduced effective dose of 40.4 % and 73.3 % (p < 0.0001), respectively. Group B1 and group C1/2 also showed significantly reduced quantitative and qualitative image quality parameters. In group B2, quantitative measures were comparable to group A, and qualitative scores were lower compared to group A but higher compared to group B1. Diagnostic confidence grading showed groups B1/2 to be adequate for everyday clinical practice. Group C2 was considered acceptable for follow-up imaging of severe acute events such as bleeding or subacute stroke.
  
  
  CONCLUSIONS
  Use of ASIR makes it possible to reduce radiation significantly while maintaining adequate image quality in non-contrast head CT, which may be particularly useful for younger patients in an emergency setting and in follow-up.
  
  
  CONCLUSIONS
  ASIR may reduce radiation significantly while maintaining adequate image quality. cCT protocol with 20 % ASIR and 40 %ASIR/60 %FBP blending is adequate for everyday clinical use. cCT protocol with 30 % ASIR and 50 %ASIR/50 %FBP blending is adequate for follow-up imaging
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kaul
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Kahn
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Huizing
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Wiener
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Grupp
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Böning
authors.affiliation: Department of Radiation Oncology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Ghadjar
authors.affiliation: Department of Radiology, Jena University Hospital, Jena, Germany.
authors.forename: D M
authors.initials: DM
authors.lastname: Renz
authors.affiliation: Department of Radiology, Charité School of Medicine and University Hospital, Berlin, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Streitparth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000528:radiation effects; D001927:Brain Diseases / Q000000981:diagnostic imaging*; D001930:Brain Injuries / Q000000981:diagnostic imaging*; D004630:Emergencies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011829:Radiation Dosage; D012680:Sensitivity and Specificity