title: Calcium scoring with prospectively ECG-triggered CT: using overlapping datasets generated with MPR decreases inter-scan variability.
abstract: OBJECTIVE
  To examine the feasibility of reducing the inter-scan variability of prospectively ECG-triggered calcium-scoring scans by using overlapping 3-mm datasets generated from multiplanar reformation (MPR) instead of non-overlapping 3-mm or 1.5-mm datasets.
  
  
  METHODS
  Seventy-five women (59-79 years old) underwent two sequential prospectively ECG-triggered calcium-scoring scans with 16 mm×1.5mm collimation in one session. Between the two scans patients got off and on the table. We performed calcium scoring (Agatston and mass scores) on the following datasets: contiguous 3-mm sections reconstructed from the raw data (A), contiguous 3-mm sections from MPR (B), overlapping 3-mm sections from MPR (C) and contiguous 1.5-mm sections from the raw data (D). To determine the feasibility of the MPR approach, we compared MPR (B) with direct raw data reconstruction (A). Inter-scan variability was calculated for each type of dataset (A-D).
  
  
  RESULTS
  Calcium scores ranged from 0 to 1455 (Agatston) and 0 to 279 mg (mass) for overlapping 3-mm sections (C). Calcium scores (both Agatston and mass) were nearly identical for MPR (B) and raw data approaches (A), with inter-quartile ranges of 0-1% for inter-scan variability. Median inter-scan variability with contiguous 3-mm sections (B) was 13% (Agatston) and 11% (mass). Median variability was reduced to 10% (Agatston and mass) with contiguous 1.5-mm sections (D) and to 8% (Agatston) and 7% (mass) with overlapping 3-mm MPR (A).
  
  
  CONCLUSIONS
  Calcium scoring on MPR yields nearly identical results to calcium scoring on images directly reconstructed from raw data. Overlapping MPR from prospectively ECG-triggered scans improve inter-scan variability of calcium scoring without increasing patient radiation dose.
authors.affiliation: Department of Radiology, Room E01.132, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. a.rutten@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Rutten
authors.forename: I
authors.initials: I
authors.lastname: Isgum
authors.forename: M
authors.initials: M
authors.lastname: Prokop
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002118:Calcium / Q000378:metabolism; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D003331:Coronary Vessels / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015203:Reproducibility of Results
chemical_list: D002118:Calcium