Dual‐bolus approach to quantitative measurement of pulmonary perfusion by contrast‐enhanced MRI

Purpose To evaluate a dual‐bolus approach to pulmonary perfusion MRI. Materials and Methods The dual‐bolus approach uses a separate low‐dose measurement for the arterial input function (AIF) to ensure linearity. The measured AIF is constructed according to a subsequent higher dose used for the tissue concentration curves in the lung. In this study a prebolus of 0.01 mmol/kg followed by doses of 0.04 mmol/kg and 0.08 mmol/kg was used. Measurements were performed using time‐resolved two‐dimensional fast low‐angle shot (2D FLASH) MRI (TE/TR = 0.73 msec/1.73 msec; flip angle = 40°; generalized autocalibrating partially parallel acquisitions (GRAPPA) factor = 3; temporal resolution = 400 msec) in end‐inspiratory breath‐hold. Results The combination of prebolus/0.04 mmol/kg resulted in a pulmonary blood flow (PBF) of 211 ± 77 mL/min/100 mL, and a pulmonary blood volume (PBV) of 20 ± 3 mL/100 mL. The combination of prebolus/0.08 mmol/kg resulted in approximately 50% lower perfusion values, most likely due to saturation effects in the lung tissue. Conclusion A dual‐bolus approach to pulmonary perfusion MRI is feasible and may reduce the problem of lacking linear relationship between the contrast‐agent concentration and signal intensity. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.