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Figure 1 Example Case

Example case showing differential lung perfusion estimated by phase-contrast magnetic resonance imaging (MRI) and perfusion scintigraphy. (A) Left, magnitude image of right pulmonary artery (RPA) (arrow) at cross-sectional plane; middle, magnitude image of left pulmonary artery (LPA) (arrow); right, phase-contrast image of LPA at systole with forward flow (upper), encoded white color (arrowhead), and at diastole with backward flow (lower), encoded black color (arrowhead). (B) Flow volume-time curve profile of left and right pulmonary arteries. S, D, correspond to phase-contrast images at systole and diastole in (A), respectively. (C) ^99mTc-labeled macroaggregates of albumin perfusion scintigraphy, posterior-anterior view. The L% was 32%. Note that estimation by net flow volume ratio resulted in an underestimation of left lung perfusion as much as –19%. (D) Bar chart showing the phase-contrast MRI measurements of absolute flow volume and differential perfusion of left lung (L%) and right lung (R%) calculated on the basis of forward flow, backward flow, and net flow volume, respectively. AA = ascending aortal; DA = descending aorta; LA = left atrium; LV = left ventricle; PA = pulmonary artery; RF = regurgitation fraction = backward flow volume divided by forward flow volume; RR = cardiac beat-to-beat interval.0