title: 99mTc tetrofosmin myocardial perfusion scintigraphy in CAD. Performance with early and standard delayed acquisition and fractional flow reserve.
abstract: OBJECTIVE
  Early stress imaging (15 min after injection of the radiopharmaceutical) in 99mTc tetrofosmin myocardial perfusion scintigraphy (MPS) has been shown feasible in comparison to standard imaging after 45 minutes, but the effects on image quality and diagnostic accuracy ask for further evaluation.
  
  
  METHODS
  97 patients (61 men, 36 women, age 69 ± 11 years) underwent both early (EA) and standard (SA) acquisition (after 14 ± 4 min and 43 ± 6 min, respectively) using 99mTc tetrofosmin gated SPECT with iterative reconstruction. Sub-diaphragmatic tracer activity and image quality was scored in a 4-point scale by blinded observers. Semiquantitative myocardial perfusion analysis was performed on a 17-segment model using standard cardiac quantification SPECT software (4 DM-SPECT). Stenoses of indeterminate haemodynamic significance were validated by measurement of fractional flow reserve (FFR).
  
  
  RESULTS
  Extra-cardiac tracer activity was more commonly found in EA (43%) than in SA (38%), but without any diagnostic impact in > 95% of the patients. The mean summed stress score was significantly higher for early than standard imaging (6.4 ± 6.3 vs. 5.6 ± 6.1, p = 0.009). The amount of ischaemic area was not significantly different (EA: 9.1 ± 6.7 % vs. SA: 7.8 ± 6.9 %). The mean stress ejection fraction was 52 ± 11% (EA) compared to 55 ± 11 % (SA) (p = ns). FFR was inversely related to SDS at early (r = -0.704, p < 0.05) and standard (r = -0.678, p < 0.05) acquisition. All patients with a FFR < 0.8 (considered as hemodynamically significant stenoses) revealed a positive scan.
  
  
  CONCLUSIONS
  Stress 99mTc tetrofosmin MPS with early acquisition is feasible and at least equally accurate when iterative reconstruction is applied.
authors: Prof. Dr. Christian Pirich, Department of Nuclear Medicine and Endocrinology, University Hospital Salzburg,, Muellner Hauptstrasse 48, 5020 Salzburg, Austria, Tel.+43/662/44 82 35 00, Fax +43/662/44 82 35 11, E-mail: c.pirich@salk.at.
authors: C
authors: C
authors: Pirich
authors: P
authors: P
authors: Keinrath
authors: L
authors: L
authors: Rettenbacher
authors: G
authors: G
authors: Rendl
authors: J
authors: J
authors: Holzmannhofer
authors: M
authors: M
authors: Hammerer
authors: J
authors: J
authors: Schuler
authors: M
authors: M
authors: Beheshti
mesh_terms: D000368:Aged; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D005858:Germany; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009943:Organophosphorus Compounds / Q000008:administration & dosage*; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin
keywords: 99mTc tetrofosmin; Myocardial perfusion scintigraphy; coronary artery disease; early acquisition; fractional flow reserve