Ultrasonic-pathological comparison of the human arterial wall. Verification of intima-media thickness.

Abstract

Recent intravascular ultrasound experience challenges the accuracy of ultrasonic measurement of arterial wall thickness. We reevaluated the correlation between histological and sonographic measurements of intima-media thickness using standard transcutaneous vascular technology. Carotid and femoral arterial segments were imaged before and after fixation using a 7-MHz linear-array vascular transducer. Log compression and beam orientation were varied. Mean intima, media, and adventitia thicknesses were measured and compared with corresponding histological tunica. Tissue processing caused 2.5% shrinkage. Intraobserver reading error was 0.7% for histology and 5.4% for sonography. Ultrasound overestimated the thickness of the intima and adventitia and underestimated the thickness of the media. For combined intima-media thickness, the differences between histology and imaging were insignificant, averaging 4% for the carotid artery and 9% for the femoral artery in the far-wall projection. In the near-wall projection, sonographic intima-media thickness was 20% less than that determined histologically. We conclude that ultrasonography is limited mainly by axial resolution in quantifying the dimensions of individual arterial tunica but is capable of accurately measuring far-wall intima-media thickness. ( In the evolution of these applications, the technology has met rigorous standards of reproducibility for measuring carotid intima-media thickness.3 The validity and accuracy of the measurement are based on pathological and clinical correlations described by Pignoli et al 4 in 1986. However, recent data from intravascular ultrasound experience have challenged the accuracy of quantitative transcutaneous vascular sonography. 5 - 9Our purpose was to reevaluate in vitro measurements of arterial wall segment thicknesses obtained by histology and by current vascular sonography. We found systematic differences that are inherent with ultrasound technology but do not invalidate the quantification of intima-media thickness. Methods Segments from common carotid and femoral arteries were taken during the autopsies of 36 male subjects who died at an age of 69 ±8 (mean±l SD) years. After removing fat and loose tissue from the adventitia, the vessels were opened longitudinally. They were then clamped to frames for fixation in 10% formalin and for imaging before and after fixation. The specimens were divided longitudinally in the line of the imaging plane. A block of tissue measuring 20 x 2.5 x thickness of the wall (mm 3 ) was taken from the vertical center of either side of the imaging plane, corresponding with the center of the sonogram (Figure 1). The cut edges were photographed on 35-mm slide film to determine the amount of shrinkage incurred during histological processing. HistologyThe sections were marked with india ink for orientation and placed in perforated plastic cassettes for ethanol dehydration, xylene substitute clearing, and paraffin embedment. Four sections (5 ftm thick) were sectioned by rotary microtome from the imaging ...

Patients With Type 3 Severe von Willebrand Disease Are Not Protected Against Atherosclerosis

“…Histological studies have shown that quantification of the intima-media thickness in the far wall of arteries by ultrasonography corresponds well with the true histological thickness. 13,15 The results of the present study and numerous other studies showed clear relationships between ultrasonographically determined intima-media thickness in the carotid and femoral artery and exposure to the established risk factors of atherosclerosis, such as arterial hypertension and hypercholesterolemia, even in young individuals. 16 -19 Furthermore, it has been shown that intima-media thickness of the carotid and femoral artery is a good indicator of atherosclerotic lesions in the coronary and peripheral arteries.…”

Effect of Oral Postmenopausal Hormone Replacement on Progression of Atherosclerosis

“…26 An RMI 413 tissue-mimicking phantom was used to monitor instrument performance. Three segments were defined: the distal 10 mm of the common carotid artery, the carotid bifurcation from the widening of the artery up to the flow divider, and the proximal 10 mm of the internal carotid artery.…”

“…Three segments were defined: the distal 10 mm of the common carotid artery, the carotid bifurcation from the widening of the artery up to the flow divider, and the proximal 10 mm of the internal carotid artery. Only measurements of the wall far from the probe were considered for calculation of outcome measures, for 2 reasons: ultrasound measurement of the near wall underestimates the true histological thickness, 26 and the visualization of the near wall was often not possible in sufficient quality, as has been reported from other trials. 27 Subjects were examined supine with a small pillow under the neck.…”

Effect of postmenopausal hormone replacement on atherosclerosis in femoral arteries

“…Atherosclerosis was measured as thickness of the intimal and medial layers of the artery as visualized by high-resolution 7.5 MHz ultrasound (Apogee CX Color; ATL, Bothel, WA, USA) [15]. An RMI 413 tissue-mimicking phantom was used to monitor instrument performance.…”

“…The examination was repeated at study end according to the same protocol, using the same angles of interrogation. Only the far wall was considered for calculation of outcome measures since ultrasound measurement of the near wall underestimates the true histological thickness and proper visualization is often difficult [5,15]. The measurement of the carotid IMT has been described previously [7].…”