title: Combining dynamic and ECG-gated ⁸²Rb-PET for practical implementation in the clinic.
abstract: OBJECTIVE
  For many cardiac clinics, list-mode PET is impractical. Therefore, separate dynamic and ECG-gated acquisitions are needed to detect harmful stenoses, indicate affected coronary arteries, and estimate stenosis severity. However, physicians usually order gated studies only because of dose, time, and cost limitations. These gated studies are limited to detection. In an effort to remove these limitations, we developed a novel curve-fitting algorithm [incomplete data (ICD)] to accurately calculate coronary flow reserve (CFR) from a combined dynamic-ECG protocol of a length equal to a typical gated scan.
  
  
  METHODS
  We selected several retrospective dynamic studies to simulate shortened dynamic acquisitions of the combined protocol and compared (a) the accuracy of ICD and a nominal method in extrapolating the complete functional form of arterial input functions (AIFs); and (b) the accuracy of ICD and ICD-AP (ICD with a-posteriori knowledge of complete-data AIFs) in predicting CFRs.
  
  
  RESULTS
  According to the Akaike information criterion, AIFs predicted by ICD were more accurate than those predicted by the nominal method in 11 out of 12 studies. CFRs predicted by ICD and ICD-AP were similar to complete-data predictions (PICD=0.94 and PICD-AP=0.91) and had similar average errors (eICD=2.82% and eICD-AP=2.79%).
  
  
  CONCLUSIONS
  According to a nuclear cardiologist and an expert analyst of PET data, both ICD and ICD-AP predicted CFR values with sufficient accuracy for the clinic. Therefore, by using our method, physicians in cardiac clinics would have access to the necessary amount of information to differentiate between single-vessel and triple-vessel disease for treatment decision making.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94107, USA. george.sayre@ucsf.edu
authors.forename: George A
authors.initials: GA
authors.lastname: Sayre
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Bacharach
authors.forename: Michael W
authors.initials: MW
authors.lastname: Dae
authors.forename: Youngho
authors.initials: Y
authors.lastname: Seo
mesh_terms: D000465:Algorithms; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D005240:Feasibility Studies; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D049268:Positron-Emission Tomography / Q000379:methods*; D012189:Retrospective Studies; D012414:Rubidium Radioisotopes
chemical_list: D012414:Rubidium Radioisotopes