A generalizable trapezoid fitting approach for estimating pulmonary transit time from first-pass perfusion cardiac MRI

Motivation: Pulmonary transit time (PTT) derived from first-pass perfusion cardiac MRI predicts major cardiovascular events. Traditional peak-to-peak PTT measurement is noise-sensitive, while the curve fitting approach to calculate centroid-to-centroid distance can be complex and unstable. Goal(s): Develop a generalizable method that is robust to variations in signal modeling types, insensitive to the first-pass and recirculation peaks, and validate its performance against curve-fitting and peak-to-peak. Approach: Fit a trapezoid with the bases defined at 0.85 and 0.5 relative to the first-pass bolus peak to avoid fitting to the first-pass and recirculation peaks. Results: Trapezoid fitting method provides accurate PTT measurements and is insensitive to noise. Impact: A trapezoid fitting method produces accurate PTT measurements derived from first-pass cardiac perfusion MRI. Our simple geometric approach is insensitive to noise and excludes both the first-pass and recirculation peaks during the fitting process.