title: Relationship of delayed enhancement by magnetic resonance to myocardial perfusion by positron emission tomography in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Presence of delayed enhancement (DE) on cardiac magnetic resonance (CMR) is associated with worse clinical outcomes in hypertrophic cardiomyopathy. We investigated the relationship between DE on CMR and myocardial ischemia in hypertrophic cardiomyopathy.
  
  
  RESULTS
  Hypertrophic cardiomyopathy patients (n=47) underwent CMR for assessment of DE and vasodilator stress ammonia positron emission tomography to quantify myocardial blood flow and coronary flow reserve. The summed difference score for regional myocardial perfusion was also assessed. Patients in the DE group (n=35) had greater left ventricular wall thickness (2.09±0.44 versus 1.78±0.34 cm; P=0.03). Stress myocardial blood flow (2.25±0.46 versus 1.78±0.43 mL/min per gram; P=0.01) and coronary flow reserve (2.78±0.32 versus 2.01±0.52; P<0.001) were significantly lower in DE-positive patients. Summed difference score (7.3±6.6 versus 0.9±1.4; P<0.0001) was significantly higher in patients with DE. A coronary flow reserve <2.00 was seen in 18 patients (51%) with DE but in none of the DE-negative patients (P<0.0001). CMR and positron emission tomography showed visually concordant DE and regional myocardial perfusion abnormalities in 31 patients and absence of DE and perfusion defects in 9 patients. Four DE-positive patients demonstrated normal regional myocardial perfusion, and 3 DE-negative patients had (apical) regional myocardial perfusion abnormalities.
  
  
  CONCLUSIONS
  We found a close relationship between DE by CMR and microvascular function in most of the patients studied. However, a small proportion of patients had DE in the absence of perfusion abnormalities, suggesting that microvascular dysfunction and ischemia are not the sole causes of DE in hypertrophic cardiomyopathy patients.
authors: Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
authors: Paco E
authors: PE
authors: Bravo
authors: Stefan L
authors: SL
authors: Zimmerman
authors: Hong-Chang
authors: HC
authors: Luo
authors: Iraklis
authors: I
authors: Pozios
authors: Mahadevan
authors: M
authors: Rajaram
authors: Aurélio
authors: A
authors: Pinheiro
authors: Charles
authors: C
authors: Steenbergen
authors: Ihab R
authors: IR
authors: Kamel
authors: Richard L
authors: RL
authors: Wahl
authors: David A
authors: DA
authors: Bluemke
authors: Frank M
authors: FM
authors: Bengel
authors: M Roselle
authors: MR
authors: Abraham
authors: Theodore P
authors: TP
authors: Abraham
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016009:Chi-Square Distribution; D003326:Coronary Circulation; D003430:Cross-Sectional Studies; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents