Calcium Distribution in the Vessel Wall and Intima-Media Thickness of the Human Carotid Arteries (original) (raw)
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Translational Neuroscience
BackgroundWe tested the hypothesis whether there is a correlation between the echogenicity and calcium and water contents of carotid plaques.Patients and methodsNinety carotid befurcations from 45 deceased patients were removed during autopsy. Thirty-four plaques were categorized as homogenous echolucent (HEL), homogenous echogenic (HEG) and heterogenous (HE) plaques based on premortem B-mode image. Water content was expressed in % of wet weight. Ca was determined by proton-induced X-ray emission and expressed in ppm. Relative optical density of the B-mode images was analyzed offline using a computer program.ResultsHEL plaques had lower Ca content (medians and IQRs: 6,145 [4,465–6,536 ppm]) compared to HEG (74,100 [15,300–1,44,500−ppm]), P ≤ 0.001). HE plaques showed an intermediate calcium content (7,310 [4,840–9,920 ppm]) that was statistically not different from echolucent plaques. Water content of HEG plaques was statistically not different from HEL and HE (HEG:53.5 [35.5–64%], ...
European Journal of Vascular and Endovascular Surgery, 2004
Objectives. The aim of this study was to compare methods of quantifying calcification of the internal carotid artery. Materials and methods. We examined 92 internal carotid artery endarterectomy specimens. Grey scale median (GSM) values were calculated from optimized B-mode scans. The degree of calcification was assessed using radiographic calcification grading. Plaques were processed histologically, and classified into: (1) calcium-rich hard plaques, (2) lipid-rich soft plaques, and (3) combined plaques. The specimens were scanned in CT-scanner. The calcium score was determined as described by Agatston. Results. Histopathology and GSM results concurred in 39 out of 92 cases (k ¼ 0.088). There was no significant correlation between the calcium score and the median GSM value (R ¼ 0.005; P ¼ 0.959). Histology and CT morphology showed a significant concordance (P , 0.001). Also CT and radiomorphological classification showed close agreement (R ¼ 0.628, P , 0.001).
American Heart Journal, 1996
The purpose of this investigation was to compare the accuracy of intravascular ultrasound (IVUS) and electron-beam computed tomography (EBCT) in quantitating human atherosclerotic plaque and calcium. In experiment I, 12 human atheroscleroUc arterial segments were obtained at autopsy and imaged by using IVUS and EBCT. The plaque from each arterial segment was dissected and a volume measurement of the dissected plaque was obtained by water displacement. The plaque from each arterial segment was ashed at 700 ° F, and the weight of the remaining ashes was used as an estimate of the calcium mass. In experiment II, 11 calcified arterial segments were obtained at autopsy and imaged by using IVUS at one site along the artery. A corresponding histologic cross section stained with Masson's trichrome was prepared. In experiment I, the mean plaque volume measured by water displacement was 165.3 ± 118.4 IJI. The mean plaque volume calculated by IVUS was 166.1 ___ 114.4 pl and correlated closely with that by water displacement (r = 0.98, p < 0.0001). The mean calcium mass measured by ashing was 19.4 ± 15.8 mg. The mean calculated calcium mass by EBCT was 19.9 ± 17.2 mg and correlated closely with that by ashing (r= 0.98, p< 0.0001). The mean calculated calcium volume by IVUS was 18.6 ± 11,2 pl and correlated linearly with the calcium mass by ashing (r= 0.87, p < 0.0003). In experiment II, the mean cross-sectional area of the calcified matrix was 1.71 ± 0.66 mm 2 by histologic examination compared with 1.44 ± 0.66 mm 2 by IVUS. There was a good correlation between the calcified cross-sectional area by histologic examination and IVUS (r = 0.76, p < 0.007); however, IVUS may underestimate the amount of calcium present depending on the intralesional calcium morphologic characteristics. In conclusion, IVUS accurately quantitates atherosclerotic plaque volume as well as the cross-sectional area and volume of intralesional calcium, especially if the calcium is localized at the base of the plaque. IVUS under-estimates the amount of calcium present because of signal drop-off when the calcium is too thick for the ultrasound to completely penetrate. In comparison, EBCT accurately quantitates calcium mass regardless of the intralesional calcium morphologic characteristics; however, EBCT does not accurately quantitate plaque volume and will miss noncalcified atherosclerotic lesions. (AM HEART J 1996;131:899-906.) A method for quantitating atherosclerotic plaque and calcium would be helpful in diagnosing and treating coronary artery disease. Intravascular ultrasound (IVUS) and electron-beam computed tomography (EBCT) are imaging modalities that have been used 11° to measure these components of coronary artery disease. IVUS uses high frequency sound waves to produce a reflectance image that has a spatial resolution of 100 pro. It visualizes the components of the arterial wall in cross section and is therefore able to quantitate the extent of plaque that cannot be obtained by angiography. EBCT uses x rays to produce a densitometric image that has a spatial resolution of 500 ~m. It is most suitable for visualizing calcium. The primary benefit of EBCT is that it is a noninvasive method that can be used to screen large numbers of patients compared with more invasive methods such as angiography and IVUS.
Intravascular Ultrasound Study of Patterns of Calcium in Ruptured Coronary Plaques
American Journal of Cardiology, 2005
Coronary calcium is intimately associated with coronary atherosclerotic plaque development, although it is controversial as to whether coronary calcium is associated with plaque instability. We analyzed 101 IVUS-detected ruptured plaques and compared them with 101 computer-matched control plaques without evidence of plaque rupture. The arc of calcium was measured every 0.5 mm within 10-mm-long segments that spanned the minimum lumen cross-sectional area, and the number and length of calcium deposits were assessed. Ruptured plaques had a significantly larger number of individual calcium deposits than control plaques (3.5 ؎ 1.7 vs 1.8 ؎ 1.1, p <0.001). However, the arc of the largest calcium deposit was smaller and the length of the largest calcium deposit in each plaque was shorter in ruptured plaques compared with control plaques (67.3°؎ 41.4°vs 114.9°؎ 77.4°, p <0.001, and 1.6 ؎ 1.3 vs 4.0 ؎ 2.7 mm, p <0.001, respectively). There was no difference in the number of superficial calcium deposits between the 2 groups, although ruptured plaques had significantly smaller arcs of superficial calcium compared with control plaques (56.2°؎ 35.5°vs 95.8°؎ 65.2°, p <0.001). Conversely, the number of deep calcium deposits was significantly larger in ruptured plaques than in control plaques (1.8 ؎ 1.4 vs 0.3 ؎ 0.6, p <0.001), although the arc of deep calcium was similar in the 2 groups. Ruptured plaques had quantitatively less calcium, especially superficial calcium, but a larger number of small calcium deposits, especially deep calcium deposits. In conclusion, ruptured plaques are associated with a larger number of calcium deposits within an arc of <90°, a larger number of deep calcium deposits, and a remodeling index.
In vivo radiofrequency-based ultrasonic tissue characterization of the atherosclerotic plaque
Stroke, 1993
Background and Purpose: The ultrasonic image can offer unique information on the composition of atherosclerotic plaque, ie, the relative content of lipids, fibrous tissue, and calcific deposits. To date, however, the echographic assessment of plaque structure is based on a subjective, qualitative evaluation of the bidimensional images. We evaluated the feasibility and accuracy of assessing, in vivo, the acoustic properties of arterial carotid plaques by means of a suitably modified echographic apparatus allowing direct access to the radiofrequency signal.