Diagnostic ultrasound ( PDFDrive )

922 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A B C
D
E
F
G
H
FIG. 26.9 Spectrum of Patterns of Heterogeneous Plaque in the Internal Carotid Artery (ICA). (A) Sagittal and (B) transverse images show
plaque (arrows) virtually completely sonolucent, consistent with heterogeneous plaque (type 1). Note smooth plaque surface. (C) Sagittal and (D)
transverse images show focal sonolucent areas within the plaque greater than 50% of plaque volume, corresponding to heterogeneous plaque
(type 2). Note the irregular surface of the plaque. (E) Sagittal image demonstrates heterogeneous plaque in the carotid bulb and homogeneous
plaque in the internal carotid artery (type 2). (F) Transverse image demonstrates heterogeneous plaque (type 2). (G) and (H) Sagittal and transverse
images demonstrate subtle heterogeneous plaque (type 2).
Ultrasound Types of Plaque Morphology
Type 1: Predominantly echolucent, with a thin echogenic
cap
Type 2: Substantially echolucent with small areas of
echogenicity (>50% sonolucent)
Type 3: Predominantly echogenic with small areas of
echolucency (<50% sonolucent)
Type 4: Uniformly echogenic
Other methods are being introduced to characterize plaque
in a more automated and reproducible manner. Reiter et al. 85
developed a gray-scale median level for echolucency of plaque
ater standardizing and adjusting the B-mode images. hey
obtained standardized gray-scale median levels for asymptomatic
patients with greater than 30% stenosis and found that decreasing
echolucency of carotid plaques over 6 to 9 months is predictive
of major cardiovascular events afecting coronary, peripheral,
and cerebrovascular circulation. However, absolute gray-scale
median levels were not associated with a speciic risk. 85