Biomedical subjects

Y F Petrank

Publications and source records attributed to Y F Petrank.

3 recordsLinked to original sources

PubMed1999

Effect of aneurysmectomy on left ventricular shape and function: case studies.

The three dimensional (3D) conformational changes in three patients with large anterior aneurysm in the left ventricle (LV) were examined before and two years after aneurysmectomy by using 3D Cine-computerized tomography (CT). Endocardial and epicardial tracings of 6-9 short axis images encompassing the entire LV were used to reconstruct the LV in 3D. Thickness and percent thickening were calculated using our 3D-volume element approach. A regional wall stress index (stress/pressure) was calculated from regional curvature and thickness. The analysis showed that following resection of the aneurysm the end-diastolic volume was reduced from 257+/-39 to 183+/-39 ml, end-systolic volume from 172+/-39 to 92+/-46 ml and, ejection fraction increased from 34+/-7 to 51+/-13%. The endocardial aneurysm area decreased from 19.7+/-15.9 to 10.1+/-6.5 cm2, whereas the normal zone area was minimally reduced from 87.4+/-17.6 to 79.8+/-10.8 cm2. The percent thickening of the normal zone increased significantly. It is documented here for the first time by detailed 3D analysis that the resection of the LV aneurysm reduces the aneurysmal area and LV size and improves the global and regional function of the remote normal zone. Therefore, the 3D approach can help to design better surgical technique for this complex operation.

Aged↗

PubMed1999

Regional differences in shape and load in normal and diseased hearts studied by three dimensional tagged magnetic resonance imaging.

OBJECTIVES: We aimed to characterize regional geometry in relation to load in two groups of patients with hypertrophic cardiomyopathy (HCM) and right ventricular pressure overload (RVPO) in relation to a group of subjects with normal left ventricular (LV) function. BACKGROUND: Both these diseases are associated with marked changes in LV shape and function, which have not been studied with detailed three dimensional tools. METHODS: Three dimensional (3D) tagged magnetic resonance imaging (MRI) was used to characterize the 3D geometry and regional stresses of the left ventricles in patients with HCM and RVPO. Curvatures, stresses, wall thickness, and endocardial motion were calculated from surface and volume elements. RESULTS: Hearts with RVPO exhibited more circumferential and meridional flattening of the septum than normal and HCM hearts. The stress indices were lowest in the HCM hearts, compared to normal and RVPO hearts, due to the larger thicknesses. There was a more significant difference between lateral wall motion and other regional wall motions in the HCM and RVPO hearts as compared to normal hearts. CONCLUSIONS: It is suggested that curvature and stress mapping by 3D tagged MRI can be used as an important clinical tool for characterizing and distinguishing between healthy and diseased hearts. The results provided here validated previous knowledge on HCM and RVPO known from planary imaging methods.

Adult↗

PubMed1995

Regional left ventricular systolic function in relation to the cavity geometry in patients with chronic right ventricular pressure overload. A three-dimensional tagged magnetic resonance imaging study.

BACKGROUND: Distortion of the left ventricular (LV) cavity in patients with right ventricular pressure overload (RVPO) is well known. However, no direct measurements of regional myocardial function in terms of myocardial shortening and wall thickening are available; therefore, exactly how RVPO disturbs LV regional performance remains unclear. By using three-dimensional (3D) tagged magnetic resonance imaging, we were able to measure regional systolic function directly. Our objective was to study the relation between the distortion of the LV circular shape and regional LV function. METHODS AND RESULTS: In nine patients with RVPO and six healthy volunteers, four parallel short-axis images (with 12 radial tags) and two mutually orthogonal long-axis images (with four parallel tags) were generated, and endocardial and epicardial borders were manually traced. By integration of the short- and long-axis images, 3D reconstruction of the LV tracking points from end diastole to end systole was obtained. Data from the midventricular two short-axis image slices were analyzed. These were then divided into anterior, lateral, posterior, and septal regions. Circumferential and longitudinal shortening were then calculated from the endocardial and epicardial tag intersection points. Wall thickness and thickening were calculated by the 3D volume-element approach. An eccentricity index (EI), the ratio of septum-to-free-wall to anteroposterior diameters, was used to describe the shape of the LV cavity. The regional curvature was also measured. The RVPO group was characterized by flattening of the septum and LV lateral wall, decreased EI reflecting the distorted LV shape, altered distribution of endocardial circumferential shortening, and preserved ejection fraction. Changes in EI closely correlated with the septal curvature. The EI was smaller at end systole, reflecting further shape distortion relative to end diastole. Reduced myocardial performance, as measured by wall thickening and circumferential and longitudinal shortening fractions, was observed for the septum. A reduction in endocardial circumferential shortening of the septal and lateral walls was directly related to the end-systolic EI. In addition, whereas for healthy subjects a linear relation between area ejection fraction and endocardial circumferential shortening was observed, in RVPO patients a curvilinear (quadratic) relation was observed. CONCLUSIONS: In patients with RVPO, compared with healthy subjects, the septal function was reduced, as evidenced by reduced thickening and shortening fractions. The distortion in LV cavity at end systole due to the flattening of the septum contributes to preserved systolic ventricular function and nonuniform distribution in endocardial circumferential shortening.

Adult↗