Abhay Divekar

Pulmonary Perfused Blood Volume with Dual-Energy CT as Surrogate for Pulmonary Perfusion Assessed with Dynamic Multidetector CT

PURPOSE To compare measurements of regional pulmonary perfused blood volume (PBV) and pulmonary blood flow (PBF) obtained with computed tomography (CT) in two pig models. MATERIALS AND METHODS The institutional animal care and use committee approved all animal studies. CT-derived PBF and PBV were determined in four anesthetized, mechanically ventilated, supine swine by using two methods for creating pulmonary parenchymal perfusion heterogeneity. Two animals were examined after sequentially moving a pulmonary arterial balloon catheter from a distal to a central location, and two others were examined over a range of static airway pressures, which varied the extents of regional PBF. Lung sections were divided into blocks and Pearson correlation coefficients calculated to compare matching regions between the two methods. RESULTS CT-derived PBF, CT-derived PBV, and their associated coefficients of variation (CV) were closely correlated on a region-by-region basis in both the balloon occlusion (Pearson R = 0.91 and 0.73 for animals 1 and 2, respectively; Pearson R = 0.98 and 0.87 for comparison of normalized mean and CV for animals 1 and 2, respectively) and lung inflation studies (Pearson R = 0.94 and 0.74 for animals 3 and 4, respectively; Pearson R = 0.94 and 0.69 for normalized mean and CV for animals 3 and 4, respectively). When accounting for region-based effects, correlations remained highly significant at the P < .001 level. CONCLUSION CT-derived PBV heterogeneity is a suitable surrogate for CT-derived PBF heterogeneity.

CRISP: Catheterization RISk score for pediatrics: A Report from the Congenital Cardiac Interventional Study Consortium (CCISC)

We sought to develop a scoring system that predicts the risk of serious adverse events (SAEs) for individual pediatric patients undergoing cardiac catheterization procedures.

MDCT-based quantification of porcine pulmonary arterial morphometry and self-similarity of arterial branching geometry

The pig is frequently used as an experimental model for studies of the pulmonary circulation, yet the branching and dimensional geometry of the porcine pulmonary vasculature remains poorly defined. The purposes of this study are to improve the geometric definition of the porcine pulmonary arteries and to determine whether the arterial tree exhibits self-similarity in its branching geometry. Five animals were imaged using thin slice spiral computed tomography in the prone posture during airway inflation pressure at 25 cmH2O. The luminal diameter and distance from the inlet of the left and right pulmonary arteries were measured along the left and right main arterial pathway in each lung of each animal. A further six minor pathways were measured in a single animal. The similarity in the rate of reduction of diameter with distance of all minor pathways and the two main pathways, along with similarity in the number of branches arising along the pathways, supports self-similarity in the arterial tree. The rate of reduction in diameter with distance from the inlet was not significantly different among the five animals (P > 0.48) when normalized for main pulmonary artery diameter and total main artery pathlength, which supports intersubject similarity. Other metrics to quantify the tree geometry are strikingly similar to those from airways of other quadrupeds, with the exception of a significantly larger length to diameter ratio, which is more appropriate for the vascular tree. A simplifying self-similar model for the porcine pulmonary arteries is proposed to capture the important geometric features of the arterial tree.

Modified stumper technique for acute postoperative bifurcation stenosis causing right ventricular failure after ross procedure

In this report, we describe a 15-year-old patient who underwent a Ross procedure for a regurgitant bicuspid aortic valve and ascending aortic dilation. After the operation was over, he could not be separated from cardiopulmonary bypass and was noted to have isolated right ventricular failure. This report takes the reader through the diagnostic evaluation, highlights the importance of invasive assessment in the immediate postoperative period, and discusses successful transcatheter intervention in the acute postoperative setting.

Porcine pulmonary artery distension during static pressure inflation

To improve the definition of the geometrical and mechanical properties of the porcine pulmonary arteries, we utilized an in vivo imaging-based approach to quantify the influence of static extravascular pressure change on pulmonary arterial geometry. The cross-sectional area and distance from the inlet of pulmonary arteries of two animals were measured over a range of static airway inflation pressure (7 cmH2O - 25 cmH2O, i.e. 0.69 kPa – 2.45 kPa). Vessels with diameter range of approximately 2.0 mm to 5.5 mm at airway inflation pressure of 25 cmH2O (2.45kPa) were considered. The results suggest that lung inflation stretches the vessels laterally, but has no statistically significant effect on diameter.

An in-vivo computed tomography approach for quantifying porcine pulmonary arterial morphometry

The objective of this study was to develop an in vivo CT imaging-based approach for pulmonary arterial morphometry measurement, and to improve the geometrical basis for studies of the porcine vasculature. The luminal diameter and distance from the inlet of left and right pulmonary arteries, and pulmonary arteries within the lungs of two porcine subjects were measured at inflation pressure of 25 cmH2O. The results suggest that the porcine pulmonary arteries have geometric self-similarity, and that this approach will have utility for systematically quantifying pulmonary arterial vessel dimensions in vivo in a larger group of animals.