title: Dipyridamole stress and rest transmural myocardial perfusion ratio evaluation by 64 detector-row computed tomography.
abstract: BACKGROUND
  Myocardial stress CT perfusion (CTP) can detect myocardial ischemia.
  
  
  OBJECTIVE
  We evaluated the transmural perfusion ratio (TPR) of dipyridamole stress CTP to detect significant coronary stenosis (>70%) defined by quantitative invasive coronary angiography (ICA).
  
  
  METHODS
  Twenty-six patients (61.6 ± 8.0 years old; 14 males), without prior myocardial infarction, with positive single-photon emission computed tomography (SPECT; <2 months) and clinical indication for ICA, underwent a customized multidetector-row CT (MDCT) protocol with rest/stress myocardial perfusion evaluation and coronary CT angiography. TPR was defined as mean subendocardial divided by mean subepicardial attenuation and quantified on rest and stress MDCT images. Abnormal TPR was defined as 2 SDs below the mean rest TPR.
  
  
  RESULTS
  All 26 patients completed the CT protocol with no adverse events. Rest TPR was measured in all patients with a mean of 1.06 ± 0.11, and abnormal TPR was considered <0.85. For 6 patients with normal coronary arteries by ICA, the mean TPR of territories with a previous positive perfusion defect in SPECT was 1.02 ± 0.18 (95% CI, 0.86-1.18; n = 6), and mean TPR of territories without perfusion defect in SPECT was 1.03 ± 0.09 (95% CI, -0.95 to 1.11; n = 12; P = 0.83). Mean stress TPR in territories with positive SPECT and significant coronary artery disease by quantitative ICA was 0.71 ± 0.13 (95% CI, -0.64 to 0.77) and in the remote myocardial was 1.01 ± 0.09 (95% CI, -0.96 to 1.06; P < 0001). In these territories, a significant Pearson's correlation was observed (r = -0.74, P < 0.001).
  
  
  CONCLUSIONS
  TPR has a good correlation with SPECT and ICA to detect significant coronary stenosis.
authors.affiliation: Cardiovascular MR and CT Section, Heart Institute (InCor), University of São Paulo Medical School and Heart Hospital (HCOR), São Paulo, Brazil. rccury@me.com
authors.forename: Roberto C
authors.initials: RC
authors.lastname: Cury
authors.forename: Tiago A
authors.initials: TA
authors.lastname: Magalhães
authors.forename: Antonio T
authors.initials: AT
authors.lastname: Paladino
authors.forename: Afonso A
authors.initials: AA
authors.lastname: Shiozaki
authors.forename: Marcela
authors.initials: M
authors.lastname: Perini
authors.forename: Tiago
authors.initials: T
authors.lastname: Senra
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Lemos
authors.forename: Ricardo C
authors.initials: RC
authors.lastname: Cury
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Rochitte
mesh_terms: D000368:Aged; D001938:Brazil; D017023:Coronary Angiography; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004176:Dipyridamole; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D004176:Dipyridamole