Assessment of spatial inhomogeneities in intima media thickness along an arterial segment using its dynamic behavior

Abstract

Hoeks. Assessment of spatial inhomogeneities in intima media thickness along an arterial segment using its dynamic behavior. Am J Physiol Heart Circ Physiol 285: H384-H391, 2003. First published March 13, 2003 10.1152/ajpheart. 00729.2002To assess locally deviating structural and mechanical properties of arterial walls, the spatial variance in end-diastolic intima media thickness (IMT) and the change in IMT during the cardiac cycle (⌬IMT) were determined along a short segment of the common carotid artery (15.86 mm), at 16 positions simultaneously. Intrasubject spatial inhomogeneities along the artery were revealed by a spatial variance significantly larger than the temporal variance over several beats. If differences between positions were confirmed, the extent of the inhomogeneity was obtained by comparison of IMT and ⌬IMT at each position with their spatial medians Ϯ the least-significant difference. Because no intersubject comparisons were necessary, a single session of several measurements was sufficient to assess inhomogeneities in the arterial wall properties of a subject, making the method independent of biological variability between subjects. The method was evaluated on 47 presumed healthy subjects (age range 21-75 yr). In 22 subjects, spatial inhomogeneities in ⌬IMT occurred (P Ͻ 0.05). In young subjects, ⌬IMT was locally decreased, i.e., in systole inhomogeneities were less compressed than their surrounding tissue. In older subjects, ⌬IMT was locally increased, i.e., the inhomogeneity was locally more compressed than its surrounding wall tissue. ultrasound; radial strain; compressibility; arterial stiffness IN THE EARLY DEVELOPMENT of cardiovascular disease (CVD), arteries first become more elastic, whereafter they stiffen (11,20). Assessing these locally changed structural and mechanical properties noninvasively in a single subject is difficult mainly due to the small spatial and temporal changes involved. Even at more advanced stages, changes in arterial wall properties are hard to determine because most methods suffer from low sensitivity and specificity. For instance, even though an increased intima media thickness (IMT) of the common carotid artery (CCA) marks changing vessel wall properties and seems to be a potential candidate to predict the future development of CVD (15, 21), the correlation between increased carotid IMT and CVD is weak. This weak correlation is a result of CVD being a focal phenomenon confined to the intima with a relatively small thickness (Ϸ2.5% of IMT). Only in more diseased arteries does the intima constitute Ͼ20% of the IMT. The correlation between IMT and CVD is further attenuated due to the physiological effects of aging (16). Hence, carotid IMT has to be significantly increased (Ϸ1.2 mm) to be conclusive (1). To enhance sensitivity, IMT is analyzed along an arterial segment and several measurements are averaged (3). However, recent lesions, fatty streaks, more advanced lesions (atheroma), and fully developed complicated plaques tend to be localized at specific sites...

Fully automated segmentation and tracking of the intima media thickness in ultrasound video sequences of the common carotid artery

“…The peak systole of the cardiac cycle can be observed in these graphs at the moment where the IMT records the minimal value and the arterial diameter is at its maximum value. These graphs provide additional proof that the proposed algorithm works correctly from end-diastolic to the peak systolic phase of the cardiac cycle, and the IMc deformation patterns depicted in Fig. 14 are in agreement with the clinical studies reported in [16] and [46].…”

“…14 brings to surface an additional research topic that received limited attention in previous studies-i.e., the variation of the IMT from the end diastolic phase to the peak systolic phase of the cardiac cycle. The change in the IMT over the cardiac cycle has the potential to complement the results that relate to the elastic properties of the arterial wall, because these measurements may have clinical use in the evaluation of the arterial stiffness [46]. The reader can refer to [16], [46], and [52]- [55], where additional studies were conducted to evaluate the relation between the change in the IMT and the arterial stiffness.…”

“…The change in the IMT over the cardiac cycle has the potential to complement the results that relate to the elastic properties of the arterial wall, because these measurements may have clinical use in the evaluation of the arterial stiffness [46]. The reader can refer to [16], [46], and [52]- [55], where additional studies were conducted to evaluate the relation between the change in the IMT and the arterial stiffness. among these, the clinical study by Meinders et al [46] is the most relevant, in which the authors evaluated in detail the dynamic behavior of the IMc to assess the local structural and mechanical changes in the arterial walls in the presence of arterial lesions.…”

“…The reader can refer to [16], [46], and [52]- [55], where additional studies were conducted to evaluate the relation between the change in the IMT and the arterial stiffness. among these, the clinical study by Meinders et al [46] is the most relevant, in which the authors evaluated in detail the dynamic behavior of the IMc to assess the local structural and mechanical changes in the arterial walls in the presence of arterial lesions. We conclude that the changes in the IMT over the cardiac cycle may have pathophysiological relevance, because the thickening of the intimal and medial layers is caused by muscle hypertrophy, inflammatory cell infiltration, deposition of lipids, and/or calcification.…”

Carotid Plaque, Arterial Stiffness Gradient, and Remodeling in Hypertension

“…We have chosen to take into account measurements of right CCA to reduce intraindividual and interindividual variability. 26 As discussed previously, 15 we gave more importance to the values of radial wall strain than to distensibility, compliance, or Young's elastic modulus because strain was directly measured as the relative change in diameter and required no mechanical assumption. We applied an arterial model in which the artery was an elastic ring of uniform elasticity and wall thickness.…”