title: Clinical comparison of circular versus noncircular acquisition using technetium-99m myocardial perfusion SPECT imaging.
abstract: The optimal orbit for myocardial SPECT imaging has not yet been determined. In order to evaluate differences in image quality and reader interpretation between orbiting methods, 50 patients scheduled for routine stress/rest 99mTc-sestamibi imaging had both a circular and a noncircular study using an ADAC Vertex dual-head imaging system.
  
  
  METHODS
  Each study was acquired using a 64 x 64 matrix, 64 stops at 25 sec per stop. Images were processed using a Butterworth filter with a frequency cutoff of 0.6 and an order of 5.0. Studies were interpreted by three experienced readers without knowledge of patient name or orbiting technique for normal and abnormal segments and overall image quality.
  
  
  RESULTS
  There was no significant difference in the semi-quantitative assessment of either defect extent or reversibility or in the quantitative assessment of defect size between the two types of orbits. However, while all 50 noncircular studies were read as good or fair quality, 23 circular studies were read as fair or poor (p = < 0.0002).
  
  
  CONCLUSIONS
  Qualitative and quantitative analysis revealed similar size and extent of perfusion defects using either circular or noncircular orbit, but images with the noncircular orbit were of significantly better image quality and may be preferable to a circular orbit with 99mTc-sestamibi.
authors.affiliation: Nuclear Cardiology Laboratory, Hartford Hospital, CT 06102, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: White
authors.forename: A
authors.initials: A
authors.lastname: Russell
authors.forename: V A
authors.initials: VA
authors.lastname: Mascitelli
authors.forename: R S
authors.initials: RS
authors.lastname: Morris
authors.forename: A R
authors.initials: AR
authors.lastname: Shehata
authors.forename: G V
authors.initials: GV
authors.lastname: Heller
mesh_terms: D000318:Adrenergic beta-Agonists; D000368:Aged; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D004176:Dipyridamole; D004280:Dobutamine; D005080:Exercise Test; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging; D015588:Observer Variation; D005082:Physical Exertion / Q000502:physiology; D019275:Radiopharmaceuticals; D012146:Rest / Q000502:physiology; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods; D014665:Vasodilator Agents
chemical_list: D000318:Adrenergic beta-Agonists; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D004280:Dobutamine; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi