Joshua Cheng

Left Ventricular Filling Pressure Assessment Using Left Atrial Transit Time by Cardiac Magnetic Resonance Imaging

Background—Left atrial (LA) size and function reflect left ventricular (LV) hemodynamics. In the present study, we developed a novel method to determine LA circulation transit time (LATT) by MRI and demonstrated its close association with LV filling pressure. Methods and Results—All subjects were prospectively recruited and underwent contrast-enhanced MR dynamic imaging. Mean LATT was determined as the time for contrast to transit through the LA during the first pass. In an invasive study group undergoing clinically indicated cardiac catheterization (n=25), LATT normalized by R-R interval (nLATT) was closely associated with LV early diastolic pressure (r=0.850, P=0.001), LV end-diastolic pressure (r=0.910, P<0.001), and mean diastolic pressure (r=0.912, P<0.001). In a larger noninvasive group (n=56), nLATT was prolonged in patients with LV systolic dysfunction (n=47) (10.1±3.0 versus 6.6±0.7 cardiac cycles in normal control subjects, n=9; P<0.001). Using a linear regression equation derived from the invasive group, noninvasive subjects were divided into 3 subgroups by estimated LV end-diastolic pressure: ⩽10 mm Hg, 11 to 14 mm Hg, and ≥15 mm Hg. There were graded increases from low to high LV end-diastolic pressure subgroups in echocardiographic mitral medial E/e′ ratio: 9±5, 11±4, and 13±3 (P=0.023); in B-type natriuretic peptide (interquartile range): 44 (60) pg/mL, 87 (359) pg/mL, and 371 (926) pg/mL (P=0.002); and in N-terminal pro–B-type natriuretic peptide: 57 (163) pg/mL, 208 (990) pg/mL, and 931 (1726) pg/mL (P=0.002), demonstrating the ability of nLATT to assess hemodynamic status. Conclusions—nLATT by cardiac MR is a promising new parameter of LV filling pressure that may provide graded noninvasive hemodynamic assessment.

Effects of respiratory cycle and body position on quantitative pulmonary perfusion by MRI.

To evaluate the performance of lung perfusion imaging using two‐dimensional (2D) first pass perfusion MRI and a quantitation program based on model‐independent deconvolution algorithm.

Effects of Hemodynamics on Global and Regional Lung Perfusion A Quantitative Lung Perfusion Study by Magnetic Resonance Imaging

Background—Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results—Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P=0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure (r=−0.728; P<0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure (P=0.016). Conclusions—Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.Background— Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results— Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P =0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure ( r =−0.728; P <0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure ( P =0.016). Conclusions— Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.

Effects of Hemodynamics on Global and Regional Lung Perfusion, A Quantitative Lung Perfusion Study by MRI

Background—Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results—Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P=0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure (r=−0.728; P<0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure (P=0.016). Conclusions—Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.Background— Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results— Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P =0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure ( r =−0.728; P <0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure ( P =0.016). Conclusions— Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.

Effects of Hemodynamics on Global and Regional Lung PerfusionClinical Perspective: A Quantitative Lung Perfusion Study by Magnetic Resonance Imaging

Background—Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results—Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P=0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure (r=−0.728; P<0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure (P=0.016). Conclusions—Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.Background— Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results— Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P =0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure ( r =−0.728; P <0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure ( P =0.016). Conclusions— Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.

Effects of Hemodynamics on Global and Regional Lung PerfusionClinical Perspective

Background—Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results—Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P=0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure (r=−0.728; P<0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure (P=0.016). Conclusions—Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.Background— Cardiac hemodynamics affect pulmonary vascular pressure and flow, but little is known of the effects of hemodynamics on lung perfusion at the tissue level. We sought to investigate the relationship between hemodynamic abnormalities in patients with left heart failure and global and regional lung perfusion using lung perfusion quantification by magnetic resonance imaging. Methods and Results— Lung perfusion was quantified in 10 normal subjects and 28 patients undergoing clinically indicated left and right heart catheterization and same day research cardiac magnetic resonance imaging. A total of 228 lung slices were evaluated. Global lung perfusion, determined as the average of 6 coronal lung slices through the anterior, mid, and posterior left and right lungs, was significantly lower in patients with reduced cardiac index (<2.5 L/min per m2): 94±30 mL/100 mL per minute versus 132±40 mL/100 mL per minute in those with preserved cardiac index (≥2.5 L/min per m2; P =0.003). The gravitational anterior to posterior perfusion gradient was inversely associated with left ventricular end-diastolic pressure ( r =−0.728; P <0.001), resulting in a blunted perfusion gradient in patients with elevated left ventricular end-diastolic pressure, a finding largely attributed to the perfusion reduction in posterior lung regions. In a multivariate regression analysis adjusting for all hemodynamic variables, altered lung perfusion gradient was most closely associated with increased mean pulmonary arterial pressure ( P =0.016). Conclusions— Increased left ventricular filling pressure and the resultant increase in pulmonary arterial pressure are associated with disruption of the normal gravitational lung perfusion gradient. Our findings underscore the complexity of heart-lung interaction in determining pulmonary hemodynamics in left heart failure.