The delay of contrast arrival in magnetic resonance first-pass perfusion imaging: a novel non-invasive parameter detecting collateral-dependent myocardium

Objectives: To establish the regional delay of contrast arrival in magnetic resonance perfusion imaging (MRPI) for the detection of collateral-dependent myocardium in patients with coronary artery disease. Design and Setting: observational study, case series; single center, university hospital. Patients: 30 patients with coronary artery disease and collateral-dependent myocardium and 17 healthy volunteers. Methods: Resting and hyperemic (adenosine) MRPI was used to determine delay time (Δtd) of contrast arrival between the left ventricle and collateral-dependent or antegradely-perfused myocardium, and myocardial perfusion (MP, ml/g/min). Results: In healthy volunteers Δtd at rest and during hyperemia were 0.8±0.4 and 0.3±0.3 sec., and MP was 1.14±0.21 and 4.23±1.12 ml/min/g. Δtd in antegradely-perfused vs. collateraldependent myocardium was 0.9±0.7 vs. 1.7±1.0 sec. at rest (p