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The knowledge of myocardial perfusion in healthy volunteers is fundamental for evaluation of patients with ischemic heart disease. The study was conducted to determine range, regional variability, and transmural gradient of myocardial perfusion in normal volunteers with Magnetic Resonance Perfusion Imaging (MRPI). Perfusion was assessed in 17 healthy volunteers (age: 20-47 yr, 11 males) at rest and adenosine-induced hyperemia using a 1.5 T MR scanner. Perfusion was quantified (mL/g/min) for the transmural myocardium and separately for the endo- and epimyocardium in the anterior, lateral, posterior, and septal left ventricular wall using the Fermi model for constrained deconvolution. Regional variabilities for resting, hyperemic perfusion, and perfusion reserve were 22 +/- 8%, 21 +/- 10%, and 35 +/- 18%. Mean resting, hyperemic perfusion, and perfusion reserve were 1.1 +/- 0.4 mL/g/min, 4.2 +/- 1.1 mL/g/min, and 4.1 +/- 1.4. Perfusion in the septum was higher at rest (1.3 +/- 0.3 mL/g/min vs. 1.0 +/- 0.3 mL/g/min, p < 0.05) and lower during hyperemia (3.6 +/- 0.8 mL/g/min vs. 4.5 +/- 1.1 mL/g/min, p < 0.03), resulting in a reduced perfusion reserve (PR) (3.2 +/- 0.9 vs. 4.5 +/- 1.4, p < 0.01) in the septum vs. the combined anterior, lateral, and posterior segments. Resting (0.9 +/- 0.3 mL/g/min vs. 1.4 +/- 0.5 mL/g/min, p < 0.01), but not hyperemic perfusion, was lower in the epi- vs. endomyocardium, resulting in a higher epimyocardial PR (4.8 +/- 1.8 vs. 3.5 +/- 1.4, p < 0.01) in all regions but the septum, where endo- and epimyocardial perfusion and perfusion reserve were not different. A considerable regional variability of myocardial perfusion was confirmed with MRPI. The exceptional anatomical position of the septum is reflected by the lack of a perfusion gradient, which was demonstrated in all other regions but the septum.

Objectives: The goal of this study was to detect transplant arteriopathy (Tx-CHD) by a reduced myocardial perfusion reserve (MPR) and resting endomyocardial/epimyocardial perfusion ratio (Endo/Epi ratio)., Background: Transplant arteriopathy often lacks clinical symptoms and is the reason for frequent surveillance angiography in heart transplant (Tx) recipients. Magnetic resonance perfusion imaging (MRPI) allows noninvasive assessment of transmural and selective endomyocardial and epimyocardial perfusion., Methods: Fifteen healthy volunteers (controls) and three groups (A, B, C) of Tx recipients were included. In controls and patients, MPR (hyperemic/resting perfusion) and Endo/Epi ratio were determined with MRPI after injection of gadolinium-diethylenetriamine pentaacetic acid at rest and during hyperemia (intravenous adenosine). Group A (n = 10) had no left ventricular (LV) hypertrophy and/or prior rejection, while patients in group B (n = 10) had at least one of these characteristics. Patients in group A and B had a normal coronary angiogram and a coronary flow reserve (CFR) of > or =2.5 (CFR = hyperemic/resting blood flow). Group C (n = 7) had Tx-CHD diagnosed by angiography and a reduced CFR (<2.5)., Results: In group C, MPR (1.7 +/- 0.5) and Endo/Epi ratio (1.1 +/- 0.2) were significantly reduced compared with controls (4.2 +/- 0.7 and 1.6 +/- 0.3; both p < 0.0001), group A (3.6 +/- 0.7 and 1.6 +/- 0.2; both p < 0.0001) and B (2.7 +/- 0.9, p < 0.01 and 1.4 +/- 0.1, p < 0.04). Transplant arteriopathy can be excluded by an MPR of >2.3 with sensitivity and specificity of 100% and 85%. If LV hypertrophy and prior rejection are excluded, Tx-CHD can be excluded by an Endo/Epi ratio of >1.3 with 100% and 80%., Conclusions: Magnetic resonance perfusion imaging detects Tx-CHD by a decreased MPR. After exclusion of LV hypertrophy and prior rejection, resting Endo/Epi ratio alone might be sufficient to indicate Tx-CHD.