Wang-Soo Lee

DICOM-based intravascular ultrasound signal intensity analysis: an Echoplaque Medical Imaging Bench study.

BackgroundMost intravascular ultrasound (IVUS) data are stored digitally using the Digital Imaging and Communications in Medicine (DICOM) standard. This allows random access to studies and improves on the major limitation of conventional grayscale IVUS. MethodsWe harvested 129 coronary arteries from 43 autopsied cases. Grayscale IVUS and virtual histology-IVUS imaging were performed beginning 30 mm distal to the ostium of each coronary artery. Grayscale IVUS was processed; and the signal intensity was determined from DICOM-stored images using a new Medical Imaging Bench system (Echoplaque-MIB). We compared 436 regions of interest. The accuracy rate was expressed using the interpolation method and 95% confidence interval (CI). ResultsPatients’ mean age was 49±9 years and 82% were men. Four patients succumbed to sudden cardiac death and 39 to noncardiac death. Grayscale IVUS signal intensity of dense calcium was 215±21.1 (95% CI: 207–223), that of fibrotic plaque was 75±17.8 (95% CI: 72–79), and that of fibrofatty plaque was 55±11.3 (95% CI: 52–59); however, the signal intensity of the necrotic core was between fibrotic plaque and dense calcium of 161±27.4 (95% CI: 153–168). Using the interpolation method, the cutoff values were as follows: fibrofatty plaque 0–65, fibrotic plaque 66–105, necrotic core 106–187, and dense calcium of at least 188. Overall, MIB grayscale had a 78.1% sensitivity and a 91.9% specificity versus histopathology. ConclusionPlaque characterization using DICOM-based grayscale IVUS signal intensity analysis may improve on the major limitation of conventional grayscale IVUS: its inability to assess plaque composition.

Effects of the Transition from Premenopause to Postmenopause on Lipids and Lipoproteins: Quantification and Related Parameters

Background/Aims The aim of this study was to quantitatively measure changes in lipids and lipoproteins during perimenopause and to identify variables related to these changes. Methods Among women who had three regular health evaluations over a span of 2-4 years, 34 women remained in the premenopausal state, 34 premenopausal women transitioned to the postmenopausal state, and 36 postmenopausal women were enrolled. The menopausal state was determined not only by a history of amenorrhea but also by levels of female sex hormones. Yearly changes in lipids were calculated using a linear regression of the three measurements. Results The transition from premenopause to postmenopause was associated with increased total cholesterol and low-density lipoprotein (LDL) cholesterol levels by 7.4 ± 8.0 mg/dL (4.2 ± 4.9%) and 6.9 ± 6.5 mg/dL (6.8 ± 7.0%) over one year, resulting in an elevation of 19.6 ± 22.6 mg/dL (10.9 ± 13.0%) and 18.9 ± 19.5 mg/dL (18.6 ± 20.3%), respectively, during perimenopause. There were no changes observed in premenopausal and postmenopausal women. Body weight, blood pressure, high-density lipoprotein (HDL) cholesterol, and triglycerides did not change in any of the three groups. In all women, changes in both total cholesterol and LDL cholesterol were associated with changes in follicle stimulating hormone (r = 0.40, p < 0.001 and r = 0.38, p < 0.001, respectively). Changes in triglycerides were associated with changes in body weight (r = 0.28, p = 0.005). Conclusions During perimenopause, total and LDL cholesterol levels increase and these changes in cholesterol are mainly dependent on changes in female sex hormones.