Left ventricular (LV) myocardial contrast enhancement can be recorded using 320 multi detector computed tomography (MDCT). We aimed to (1) assess patterns of regional myocardial perfusion at rest and compare them with NH(3) positron emission tomography (PET) (2) and to assess the effect of intravenous adenosine infusion on regional myocardial perfusion. To evaluate myocardial perfusion patterns at rest, we scanned 14 healthy subjects with PET and 14 age and gender matched subjects with 320 MDCT. To evaluate the effect of adenosine stress on relative perfusion patterns 14 subjects with near-normal epicardial coronary arteries were studied at rest and during adenosine stress. Relative perfusion was assessed as attenuation density (AD) in 16 segments of the LV, and each segment was divided into 3 layers: endo-, mid- and epi-cardial. During rest the relative AD by MDCT was lower in the lateral wall compared with the remainder of the LV (P