title: Computed tomography stress myocardial perfusion imaging in patients considered for revascularization: a comparison with fractional flow reserve.
abstract: OBJECTIVE
  Adenosine stress computed tomography myocardial perfusion imaging (CTP) is an emerging non-invasive method for detecting myocardial ischaemia. Its value when compared with fractional flow reserve (FFR), a highly accurate index of ischaemia, is unknown. Our aim was to determine the diagnostic accuracy of CTP and its incremental value when used with computed tomography coronary angiography (CTA) for detecting ischaemia compared with FFR.
  
  
  RESULTS
  Forty-two patients (126 vessel territories), who had at least one ≥50% angiographic stenosis on invasive angiography considered for non-urgent revascularization, were included and underwent FFR and CT assessment, including CTP, delayed contrast enhancement scan and CTA all acquired using 320-detector row CT, and prospective ECG gating. Fractional flow reserve was determined in 86 territories subtended by vessels with ≥50% stenosis upon visual assessment. Fractional flow reserve ≤0.8 was considered to indicate significant ischaemia. Computed tomography myocardial perfusion imaging correctly identified 31/41 (76%) ischaemic territories and 38/45 (84%) non-ischaemic territories. Per-vessel territory sensitivity, specificity, positive, and negative predictive values of CTP were 76, 84, 82, and 79%, respectively. The combination of a ≥50% stenosis on CTA and perfusion defect on CTP was 98% specific for ischaemia, while the presence of <50% stenosis on CTA and normal perfusion on CTP was 100% specific for exclusion of ischaemia. Mean radiation for CTP and combined CT was 5.3 and 11.3 mSv, respectively.
  
  
  CONCLUSIONS
  Computed tomography myocardial perfusion imaging is moderately accurate in identifying perfusion defects associated with ischaemia as assessed by FFR in patients considered for revascularization. In territories, where CTA and CTP are concordant, CTA/CTP is highly accurate in the detection and exclusion of ischaemia. This is achievable with acceptable radiation exposure using 320-detector row CT and prospective ECG gating.
authors.affiliation: Monash Cardiovascular Research Centre, Monash Heart,  Southern Health, 246 Clayton Road, Clayton, 3168 VIC, Australia.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ko
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.forename: Michael
authors.initials: M
authors.lastname: Leung
authors.forename: Paul R
authors.initials: PR
authors.lastname: Antonis
authors.forename: Arthur
authors.initials: A
authors.lastname: Nasis
authors.forename: Marcus
authors.initials: M
authors.lastname: Crossett
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Hope
authors.forename: Sam J
authors.initials: SJ
authors.lastname: Lehman
authors.forename: John
authors.initials: J
authors.lastname: Troupis
authors.forename: Tony
authors.initials: T
authors.lastname: DeFrance
authors.forename: Sujith K
authors.initials: SK
authors.lastname: Seneviratne
mesh_terms: D000241:Adenosine; D000368:Aged; D017023:Coronary Angiography / Q000379:methods; D023921:Coronary Stenosis / Q000175:diagnosis; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009204:Myocardial Revascularization / Q000379:methods; D015588:Observer Variation; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine