Biomedical subjects

Philip R Liebson

Publications and source records attributed to Philip R Liebson.

28 records · Page 2Linked to original sources

PubMed2004

Effect of contrast enhancement on measurement of carotid artery intimal medial thickness.

Previous studies have used standard B-mode ultrasound to quantify the aggregate mean intimal medial thickness (IMT) of the near and far wall of the common carotid artery (CCA). Many investigators have had difficulty in accurately evaluating the near wall IMT secondary to difficulty in discerning the vessel lumen and intima. The purpose of this study is to determine the effect of contrast enhanced ultrasound on IMT measurement when compared with non-enhanced images. Twenty-six patients who had standard carotid ultrasounds completed over a 6-month period were evaluated, with 24 imaged by the same sonographer. Five to six measurements of the near and far walls were obtained over a 1 cm distance, beginning and ending 0.5 cm and 1.5 cm proximal to the carotid bifurcation. The measurements were made with and without the contrast agent Optison (perflutren protein type-A microspheres), which was given as an i.v. bolus (0.5-0.7 cc). Of those imaged by the same sonographer, 40 carotid arteries were examined and a total of 867 measurements were obtained. A total of 10% of the carotid ultrasounds were restudied approximately 1 month after the initial interpretation to assess observer accuracy. The near wall CCA mean (SD) IMT was 0.075 (0.019) cm for left with contrast versus 0.067 (0.023) cm for left without contrast and 0.089 (0.024) cm for right with versus 0.071 (0.022) cm for right without, p < or = 0.0001 both sides. For the far wall of the CCA, the mean (SD) IMT comparison was 0.075 (0.021) cm for left with versus 0.070 (0.016) cm for left without, p = 0.005, and 0.070 (0.023) cm for right with versus 0.070 (0.016) cm for right without, p = 0.68. In conclusion, contrast-enhanced IMT measurement showed a highly statistically significant difference in near carotid wall thickness determinations versus non-contrast values. The thicker measurement is in agreement with previously reported data showing that non-contrast images underestimated near wall common carotid IMT in histologic samples.

Aged↗

PubMed2004

Left ventricular structure and systolic function in African Americans: the Atherosclerosis Risk in Communities (ARIC) study.

OBJECTIVES: To estimate prevalence of left ventricular (LV) hypertrophy and its relation to systolic function in a population-based sample of African Americans. DESIGN: A baseline 2D guided M-mode echocardiogram was conducted as part of a longitudinal cohort study to assess prevalence and cross-sectional relationships between echocardiographic and clinical parameters. SETTING: Data were collected as part of the Atherosclerosis Risk in Communities study. PARTICIPANTS: Analysis is limited to 1543 African Americans, aged 51-70 years, without clinically apparent cardiovascular or echocardiographically determined valvular disease. MAIN OUTCOME MEASURES: LV hypertrophy prevalence was defined as LV mass/ height2.7 > or = 51 g/m2.7. LV systolic chamber function was assessed at the midwall using the ratio of observed midwall fractional shortening (MWS%) to the value predicted from circumferential end-systolic stress. RESULTS: The prevalence of LV hypertrophy was 33% in men, 38% in women. The prevalence of concentric hypertrophy (LV hypertrophy with relative wall thickness > or = 0.45) was greater than that of eccentric hypertrophy (men: 24% vs 9%; women: 27% vs 11% women). Observed/predicted (O/P) MWS% was strongly and inversely related to LV mass/ height2.7 (P<.001) and LV hypertrophy (P<.001). The O/P MWS% was inversely related to LV mass/height2.7 quartile: O/P MWS% was 106% and 99% in the first and 97% and 89% in the fourth quartile of LV mass/height2.7 for men and women, respectively. Adjusting for age, adiposity, diabetes, blood pressure, antihypertensive medication use, and smoking did not remove association between O/P MWS% and LV mass/height2.7. CONCLUSIONS: LV hypertrophy was highly prevalent in this population-based middle-aged sample of African Americans and was associated with poorer LV systolic chamber function.

Black or African American↗

PubMed2003

Comparison of m-mode echocardiographic left ventricular mass measured using digital and strip chart readings: the Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: Epidemiological and clinical studies frequently use echocardiography to measure LV wall thicknesses and chamber dimension for estimating quantitative measures of LV mass. While echocardiographic M-mode LV images have traditionally been measured using hand-held calipers and strip-chart paper tracings, digitized M-mode LV image measurements made directly on the computer screen using electronic calipers have become standard practice. We sought to determine if systematic differences in LV mass occur between the two methods by comparing LV mass measured from simultaneous M-mode strip chart recordings and digitized recordings. METHODS: The Atherosclerosis Risk in Communities study applied the latter method. To determine if systematic differences in LV mass occur between the two methods, LV mass was measured from simultaneous M-mode strip chart recordings and digitized recordings. RESULTS: We found no difference in LV mass (p > .25) and a strong correlation in LV mass between the two methods (r = 0.97). Neither age, sex, nor hypertension status affected the correlation of LV mass between the two methods. CONCLUSIONS: We conclude that digital estimates of LV mass provide unbiased estimates comparable to the strip-chart method.

Cohort Studies↗

PubMed2003