My research interests include evaluating myocardial microcirculation with computed tomography (CT).
CT analysis of myocardial microcirculatory function (Investigators: E. L. Ritman, L. O. Lerman, Z Bajzer)
The premise driving this proposal is that altered function of the myocardial microvasculature is a significant component of atherosclerosis, diabetes, and hypertension. The functional status of the intramyocardial resistance and exchange vessels is quantitated by CT image analysis of intramyocardial blood flow, blood volume, and endothelial permeability.
These CT-based parameters are quantitatively evaluated in experimental animals by comparison to in vivo techniques (intracoronary Doppler) and in vitro testing (perfused isolated microvessel) of the myocardial microcirculation. First, we use acute microvascular embolization to evaluate the sensitivity and specificity with which different components of microcirculation can be characterized. Second, we evaluate the CT image analysis method's ability to detect, discriminate and quantitate disease states of the coronary micro vasculature in diet-induced hypercholesterolemia and in chronic coronary artery stenosis induced by intracoronary stenting.
Multidisciplinary MICRO-CT 3-D imaging resource (Cardiovascular Investigators: B Kantor, A. Lerman and L.O. Lerman, E.L. Ritman, J.C. Romero, Orthopedics: M Yaszemski , Gastro-intestinal: N.F. LaRusso, )
The basis of this proposal is a recently implemented micro-CT scanner that scans volumes up to 2 cm^3 consisting of 512^3 cubic voxels with side dimensions ranging from 5 to 20 micrometer. Of particular relevance to cardiovascular studies is the quantitation of basic structure-to-function relationships in pathophysiological processes, such as the impact of hypertrophy on the myocardial fiber architecture or coronary artery branching geometry relationship to shear stress at the endothelium. Coronary artery wall calcification and vasa vasorum are also being studied. Other organ systems are also under study, the microvasaculature of colonic adenomas, the biliary tree branching geometry, and bone micro-architecture. We have also implemented a CRYOSTATIC MICRO-CT capability for scanning frozen specimens so that after the micro-CT scan, the specimens can be used for mRNA and other analyses that are destructive, but require fresh frozen specimens.
Coronary Vasa Vasorum - role of 3D branching geometry. (E.L. Ritman, L.O. Lerman, A. Lerman, )
This project uses the micro-CT images of the coronary artery VASA VASORUM to compute the pressure drop along the vasa vasorum and compares this to the extravascular intramural pressure in the wall that is transmitted from the "parent" arterial lumen. We also use cryostatic micro-CT to measure the pleakiness of the coronary and vasa vasorum endothelium - a factor in atherosclerosis , diabetes and hypertension.
We are also using POLYCAPILLARY X-RAY OPTICS to develop MICRO-SPECT and X-RAY SCATTER IMAGING. These modalities will provide , respectively, a broader spectrum of functional (molecular) information and micro-structural anisotropy at the 100 micrometer voxel resolution level.