Sonographic assessment of intima-media thickness (IMT)and plaque morphology of the carotid system: A comparative study

Clinical History

Investigate the potential association of increase in IMT with carotid artery disease extension, plaque occurrence and morphology and formation of carotid bifurcation stenosis.

Imaging Findings

The best means for assessing carotid plaque thickness is transverse images, which most accurately show the maximum thickness of plaque and the resultant degree of luminal narrowing.In the present study we evaluated IMT in the distal part of CCA and atherosclerosis of carotid bifurcation.250 patients 140 females and 110 males referred for color duplex ultrasound were included. Risk factors for cerebrovascular disease were recorded. Measurements of IMT adjacent to the bulb and plaque characterization and classification were realized in long and short-axis images. Colour doppler Ultrasound was performed by Aspen Acuson scanner and linear transducer (5-7)MHz.Coefficients of variation and k-statistics were used for assessment of variability in IMT measurements and plaque characterization respectively. Controversy cases underwent SHU 508A contrast agent injection.

Discussion

Atherosclerotic plaque is rappresented sonographically by echogenic material that thickens the intimal reflection and encroaches on the arterial lumen.Minimal plaque formation may be detected by measuring the total intima-media thickness.A measurement greater than 1.2mm appears to accurately indicate the presence of plaque.Reproducibility of plaque detection with ultrasound was found to be only fair to good in a large multicenter study.Causes of interobserver variation include level of the technologists skill, ultrasound image quality, failure to examine the same vascular segment, and lack of a uniform definition of findings that indicate the presence of plaque.Plaque evaluation is based on quantification of extent and severity. The length of the vessel (cephalocaudal) affected by plaque and imaged in longitudinal ultrasound axis of the carotid arteries gives a satisfactory estimation of extent. The thickness of the plaque is a measure of severity. This is more difficult to define sonografically, because plaque varies in thickness from one location to another.

Differential Diagnosis List

Final Diagnosis

Color doppler ultrasonography is accurate for assessment of IMT

URL:	https://eurorad.org/case/5929
DOI:	10.1594/EURORAD/CASE.5929
ISSN:	1563-4086