Influence of bolus volume and dose of gadolinium chelate for first‐pass myocardial perfusion MR imaging studies

First‐pass MR myocardial perfusion measurements require a well‐defined left ventricular (LV) blood pool input function. We used a peripheral intravenous (IV) injection of a gadolinium (Gd) chelate to obtain a well‐characterized LV time‐intensity curve. Using a strongly T1‐weighted subsecond MR sequence, we performed cardiac MR imaging after administering an IV bolus injection of one of three different doses of the Gd chelate: a standard dose (0.1 mmol/kg, group I, n = 8); a low dose with two bolus volumes (0.01 mmol/kg, l/10e bolus volume, group n, n = 7, and 0.01 mmol/kg diluted in saline, same bolus volume as group I, group III, n = 3); and an intermediate dose (0.05 mmol/kg, group IV, n = 5). Unlike in group I (high dose), in groups n and m (low dose), the LV curve had a well‐defined first peak, followed by a downslope and a recirculation peak. With the intermediate dose (group IV), a saturation effect still remained on the LV curve. The signal intensity (SI) enhancement of the myocardium was respectively 580 ± 77% at 0.1 mmol/kg, 362 ± 95% at 0.05 mmol/kg, and at 0.01 mmol/kg, it was 184 ± 33% in group II and 272 ± 8% in group m. In conclusion, with subsecond T1‐weighted MR imaging and a low dose of Gd chelate (i.e., 0.01 mmol/kg). the LV input function is a well‐defined first step for MR perfusion modeling.