title: Relationship of coronary calcium and myocardial perfusion in individuals with chest pain. Assessed by integrated rubidium-82 PET-CT.
abstract: OBJECTIVE
  The integrated value of coronary calcium scoring added to myocardial perfusion assessment in hybrid PET-CT imaging remains poorly defined. In the present study, we sought to determine the relationship between calcium burden, other risk factors, and tissue perfusion in a group of patients with chest pain and predominantly intermediate likelihood for coronary artery disease.
  
  
  METHODS
  In 70 patients, coronary calcium scores (CCS) were obtained in addition to rest/dipyridamole stress 82Rb perfusion images using a GE Discovery Rx hybrid PET-CT system. From static perfusion images, summed rest, stress and difference scores (SRS, SSS, SDS) were calculated using a 20-segment model. Absolute CCS was determined according to Agatston and age-, gender-, and ethnicity-matched CCS percentiles were calculated using the MESA database.
  
  
  RESULTS
  SSS, SRS and SDS were abnormal (>or=4) in 25 (36%), 17 (24%), and 12 (17%) patients. Mean CCS according to Agatston was 180+/-446(range 0-2122), and CCS percentile was 42+/-43(range 0-99). Absolute CCS correlated mildly but significantly with SSS (r=0.31, p=0.01), while CCS percentile did not (r=0.11, p=0.36). Of 49 patients with normal perfusion, 25 (57%) had CCS=0, and 8 (18%) had a CCS percentile>or=75th. Of 35 patients with a CCS=0, 26 (74%) had normal perfusion. Individuals in whom review of patient records revealed events during follow-up (n=10) had significantly higher SSS than those where no events were recorded (6.0+/-7.2 versus 2.9+/-3.1, p=0.03), and there was a trend towards higher CCS percentiles (62+/-36 versus 35+/-43, p=0.06).
  
  
  CONCLUSIONS
  Coronary calcifications and myocardial tissue perfusion, as interrogated in a single PET-CT imaging session, show only partial agreement in patients with chest pain. Both tests seem to reflect different pathophysiologic components, and may be complementary for definition of individual disease patterns.
authors.affiliation: Division of Nuclear Medicine, Johns Hopkins University Medical Institutions, 601 N. Caroline St., JHOC 3225. Baltimore, Maryland 21287, USA.
authors.forename: T L Y
authors.initials: TL
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Merrill
authors.forename: P
authors.initials: P
authors.lastname: Hill
authors.forename: F M
authors.initials: FM
authors.lastname: Bengel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000378:metabolism*; D002637:Chest Pain / Q000000981:diagnostic imaging*; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology; D004176:Dipyridamole / Q000493:pharmacokinetics; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012044:Regression Analysis; D012189:Retrospective Studies; D012414:Rubidium Radioisotopes
chemical_list: D012414:Rubidium Radioisotopes; D004176:Dipyridamole; D002118:Calcium