title: Low-dose CT coronary angiography using iterative reconstruction with a 256-slice CT scanner.
abstract: OBJECTIVE
  To explore whether computer tomography coronary angiography (CTCA) using iterative reconstruction (IR) leads to significant radiation dose reduction without a significant loss in image interpretability compared to conventional filtered back projection (FBP).
  
  
  METHODS
  A consecutive series of 200 patients referred to our institution to undergo CTCA constituted the study population. Patients were sequentially assigned to FBP or IR. All studies were acquired with a 256-slice CT scanner. A coronary segment was considered interpretable if image quality was adequate for evaluation of coronary lesions in all segments ≥ 1.5 mm.
  
  
  RESULTS
  The mean age was 56.3 ± 9.6 years and 165 (83%) were male, with no significant differences between groups. Most scans were acquired using prospective ECG triggering, without differences between groups (FBP 84% vs IR 82%; P = 0.71). A total of 3198 (94%) coronary segments were deemed of diagnostic quality. The percent assessable coronary segments was similar between groups (FBP 91.7% ± 4.0% vs IR 92.5% ± 2.8%; P = 0.12). Radiation dose was significantly lower in the IR group (2.8 ± 1.4 mSv vs 4.6 ± 3.0 mSv; P < 0.0001). Image noise (37.8 ± 1.4 HU vs 38.2 ± 2.4 HU; P = 0.20) and signal density (461.7 ± 51.9 HU vs 462.2 ± 51.2 HU; P = 0.54) levels did not differ between FBP and IR groups, respectively. The IR group was associated to significant effective dose reductions, irrespective of the acquisition mode.
  
  
  CONCLUSIONS
  Application of IR in CTCA preserves image interpretability despite a significant reduction in radiation dose.
authors.affiliation: Patricia Carrascosa, Gastón A Rodriguez-Granillo, Carlos Capuñay, Alejandro Deviggiano, Department of Cardiovascular Imaging, Diagnóstico Maipú, Buenos Aires, B1602ABQ, Argentina.
authors.forename: Patricia
authors.initials: P
authors.lastname: Carrascosa
authors.forename: Gastón A
authors.initials: GA
authors.lastname: Rodriguez-Granillo
authors.forename: Carlos
authors.initials: C
authors.lastname: Capuñay
authors.forename: Alejandro
authors.initials: A
authors.lastname: Deviggiano
keywords: Iterative reconstruction; Low-dose computer tomography coronary angiography