Carotid ultrasound

Association of the High-Sensitivity C-Reactive Protein-to-Albumin Ratio with Carotid Atherosclerotic Plaque: A Community-Based Cohort Study

Background

The inflammatory response is a pivotal factor in accelerating the progression of atherosclerosis. The high-sensitivity C-reactive protein-to-albumin ratio (CAR) has emerged as a novel marker of systemic inflammation. However, few studies have shown the CAR to be a promising prognostic marker for carotid atherosclerotic disease. This study aimed to analyse the predictive role of the CAR in carotid atherosclerotic disease.

Methods

This community-based cohort study recruited 2003 participants from the Rose asymptomatic IntraCranial Artery Stenosis (RICAS) study who were free of stroke or transient ischemic attack. Carotid atherosclerotic plaques and their stability were identified via carotid ultrasound. Logistic regression models were utilized to investigate the association between CAR and the presence of carotid atherosclerotic plaques.

Results

The prevalence of carotid atherosclerotic plaques was 38.79% in this study. After adjusting for clinical risk factors, including sex, age, dyslipidemia, hypertension, diabetes mellitus (DM), and smoking and drinking habits, a high CAR-level was independently associated with carotid plaque (odds ratio [OR] of upper: 1.46, 95% confidence interval [CI]: 1.13-1.90, P = 0.004; P for trend = 0.011). The highest CAR tertile was still significantly associated with carotid plaques among middle-aged (40-64 years) or female participants. Notably, an elevated CAR may be an independent risk factor for vulnerable carotid plaques (OR of upper: 2.06, 95% CI: 1.42-2.98, P < 0.001; P for trend <0.001).

Conclusion

A high CAR may be correlated with a high risk of carotid plaques, particularly among mildly aged adults (40-64 years) or females. Importantly, the CAR may be associated with vulnerable carotid plaques, suggesting that the CAR may be a new indicator for stroke prevention.

Prevalence of asymptomatic atherosclerosis of extracranial vessels among hypertensive patients in southern Egypt: An extracranial duplex study

Objectives:

The prevalence of atherosclerosis in extracranial vessels among hypertensive patients in southern Egypt is still unknown. Carotid ultrasound is an accurate method used to identify and follow patients with cerebrovascular disorders. The aim of our study is to detect the prevalence and pattern of extracranial atherosclerosis among those patients.

Methods:

Our case-control study was performed from January 2017 to January 2018, including 200 subjects, 100 patients recruited consecutively from the Hypertension Clinic in Assiut University hospitals, Egypt, and 100 healthy controls. Detailed history collection and thorough physical examinations were carried out for each patient. All subjects underwent extracranial ultrasound. We omitted patients with history of ischemic stroke and TIAs.

Results:

The presence of increased intima media thickness was detected in 37 patients (37%). 22 patients (22%) had internal carotid artery (ICA) stenosis, 17 patients (17%) had non-significant stenosis <50%, while five patients (5%) had stenosis 50-69%. 9% had stenosis < 50% in vertebral artery. In addition, age and uncontrolled hypertension have a greater impact on increasing the CCA intima media thickness, which is considered an early sign of atherosclerosis.

Conclusions:

Uncontrolled hypertension is an important risk factor for atherosclerosis and hence ischemic stroke (IS). The cost of screening is considered low compared to IS management. Greater emphasis should be directed toward regular screening programs in this risky population.

Imaging of the ulcerated carotid atherosclerotic plaque: a review of the literature

Abstract

Carotid atherosclerotic disease constitutes a major modern health problem whose diagnosis primarily relies on imaging. Grading of stenosis has been long used as the main factor for risk stratification and guiding of management. Nevertheless, increasing evidence has shown that additional plaque characteristics such as plaque composition and surface morphology play an important role in the occurrence of symptoms, justifying the term “vulnerable plaque”. Carotid plaque surface characteristics either in the form of surface irregularities or ulceration represent an important factor of vulnerability and are associated with the occurrence of neurologic symptoms. The delineation of the carotid plaque surface can be performed with virtually all imaging modalities including ultrasound, contrast-enhanced ultrasound, multi-detector computed tomography angiography, magnetic resonance angiography and the traditional reference method of angiography. These techniques have shown varying levels of diagnostic accuracy for the identification of ulcerated carotid plaques or plaque surface irregularities. As a consequence and given its high clinical significance, radiologists should be familiar with the various aspects of this entity, including its definition, classification, imaging findings on different imaging modalities and associations. The purpose of this review is to present the current literature regarding carotid plaque ulcerations and present illustrative images of ulcerated carotid plaques.

Teaching Points

• Plaque surface and ulceration represent risk factors for stroke in carotid disease.

• Characterisation of the plaque surface and ulcerations can be performed with every modality.

• US is the first-line modality for carotid disease and identification of ulcerations.

• The administration of microbubbles increases US accuracy for diagnosis of carotid ulceration.

• MDCTA and MRA are valuable for diagnosing ulceration and evaluating plaque composition.

Diagnostic vascular ultrasonography with the help of color Doppler and contrast-enhanced ultrasonography

The use of ultrasonography and especially of contrast-enhanced ultrasonography (CEUS) in the diagnosis of vascular pathologies before and after interventions has significantly increased over the past years due to the broader availability of modern ultrasound systems with CEUS capabilities and more trained user experience in this imaging modality. For the preinterventional and postinterventional work-up of carotid diseases, duplex ultrasound as well as CEUS have been established as the standard-of-care examination procedures for diagnosis, evaluation, and follow-up. In addition to its use for carotid arterial diseases, ultrasonography has also become the primary modality for the screening of vascular pathologies. This review describes the most common pathologies found in ultrasonography of the carotid arteries, the abdominal aorta, and the femoral arteries.

Common Carotid Artery Occlusion

Common carotid artery (CCA) occlusion is an uncommon cause of stroke. Doppler ultrasound (DUS) has been reported as a sensitive diagnostic tool in this pathology. Two cases of CCA occlusion are presented as DUS. In one case, the authors found the rare occurrence of reversed flow in the internal carotid artery (ICA) nourishing the external carotid artery (ECA). In the other, both CCA and ICA were occluded, and the contralateral ICA had a significant stenosis. Both patients were submitted to angiography. The role of DUS and its limitations in the presence of CCA occlusion are described and discussed.

The role of contrast-enhanced ultrasound in imaging carotid arterial diseases

The standard of care for the initial diagnosis of carotid artery bifurcation diseases is carotid duplex ultrasound. Carotid abnormalities or difficult examinations may represent a diagnostic challenge in patients with clinical symptoms as well as in the follow-up after carotid endarterectomy, carotid artery stenting or other interventions. A promising new method in the diagnosis and follow-up of pathologic carotid diseases is contrast-enhanced ultrasound (CEUS). In comparison with magnetic resonance imaging or computed tomography, the contrast agents used for CEUS remain within the vascular space and hence can be used to study vascular disease and could provide additional information on carotid arterial diseases. This review describes the current carotid duplex ultrasound examination and compares the pathologic findings with CEUS.

New criteria for the sonographic diagnosis of a plaque ulcer in the extracranial carotid artery

OBJECTIVE

The diagnostic power of carotid sonography in detecting plaque ulcers may be inadequate when using the conventional criteria. We aimed to evaluate the usefulness of new criteria that we devised through a preliminary analysis of 50 endarterectomy cases before the present series.

SUBJECTS AND METHODS

Thirty carotid arteries of 30 consecutive patients who underwent endarterectomy (28 men; age range, 46-83 years) were studied. In the long- and short-axis B-mode images of carotid arteries, the concavity of the plaque surface and the surface echo intensity were carefully investigated. The conventional criteria stipulate a concavity larger than 2 × 2 mm with a well-defined back wall and flow reversal within the recess. Our new criteria specify a concavity in the plaque with the basal border echo weaker than that of the adjacent plaque surface, regardless of size. The final diagnosis was based on surgical and histologic findings.

RESULTS

Among the 30 carotid arteries, 14 arteries had 14 ulcers at surgery. Seventeen concavities were detected by sonography, and 12 of them, including six smaller than 2 × 2 mm, were truly ulcers. Two concavities with an echo intensity of the basal border equal to or greater than that of the adjacent surface were not true ulcers. Only two of 14 ulcers were not detected by sonography. The sensitivity and specificity of the conventional criteria were 35.7% and 75.0%, respectively, and those of our new criteria were 85.7% and 81.3%, respectively.

CONCLUSION

Our new criteria for the sonographic diagnosis of plaque ulcer are more useful than the conventional ones.

Comprehensive data visualization for high resolution endovascular carotid arterial wall imaging

Carotid angioplasty and stenting is a minimally invasive endovascular procedure that may benefit from in vivo high resolution imaging for monitoring the physical placement of the stent and potential complications. The purpose of this pilot study was to evaluate the ability of optical coherence tomography to construct high resolution 2D and 3D images of stenting in porcine carotid artery. Four Yorkshire pigs were anaesthetized and catheterized. A state-of-the-art optical coherence tomography (OCT) system and an automated injector were used to obtain both healthy and stented porcine carotid artery images. Data obtained were then processed for visualization. The state-of-the-art OCT system was able to capture high resolution images of both healthy and stented carotid arteries. High quality 3D images of healthy and stented carotid arteries were constructed, clearly depicting vessel wall morphological features, stent apposition and thrombus formation over the inserted stent. The results demonstrate that OCT can be used to generate high quality 3D images of carotid arterial stents for accurate diagnosis of stent apposition and complications under appropriate imaging conditions.

Imaging of carotid arterial diseases with contrast-enhanced ultrasound (CEUS)

Carotid duplex ultrasound is the standard of care for the initial diagnosis of carotid artery bifurcation diseases. But in difficult examinations, carotid abnormalities are commonly encountered and may represent a diagnostic challenge in patients with clinical symptoms as well as in the follow up after carotid endarterectomy or carotid artery stenting. Contrast enhanced ultrasound (CEUS) with low mechanical index (low MI) is a promising new method in the diagnosis and follow up of pathological carotid diseases. Unlike most contrast agents used for magnetic resonance imaging or computed tomography, the microbubbles used in CEUS with SonoVue(®) remain within the vascular space and hence can be used to study vascular disease. In addition to improving current carotid structural scans, CEUS has potential to improve or add extra information on carotid arterial diseases. This review describes the current carotid duplex ultrasound examination and compares the pathological findings with CEUS.

When to image carotid plaque inflammation with FDG PET/CT

OBJECTIVE

Quantification of 18-fluorodeoxyglucose (FDG) uptake in inflamed high-risk carotid atherosclerotic plaques is challenged by the spatial resolution of positron emission tomography (PET) and luminal blood activity. Late acquisition protocols have been used to overcome these challenges to enhance the contrast between the plaque and blood-pool FDG activity. However, for prospective studies the late acquisition is inconvenient for the patient and staff, and most retrospective studies of plaque uptake use data from early acquisition protocols. The objective was to evaluate changes in the quantification methods of FDG uptake in carotid artery plaques between early and late PET scans.

METHODS

FDG uptake 1 and 3 h after tracer injection was compared in 19 carotid artery plaques. The average plaque maximum standardized uptake value (SUVmax) and a target to background ratio (TBR), using venous blood-pool activity as background, were evaluated at the two time points. These methods have been shown earlier to quantitate the degree of inflammation in late hour scans.

RESULTS

A good individual plaque FDG uptake consistency was found between the two time points for SUVmax, r²=0.86. In contrast, the ratio method did not conserve the results between the two time points: TBR r²=0.34. For both methods, absolute values changed over time. TBR values generally increased as blood pool activity decreased, whereas the individual plaque SUVmax values showed both increases and decreases over time.

CONCLUSION

Identification of carotid plaque inflammation with PET can be performed 1 h after FDG injection using SUVmax for plaque FDG uptake quantification.

Molecular pathology in vulnerable carotid plaques: correlation with [18]-fluorodeoxyglucose positron emission tomography (FDG-PET)

OBJECTIVES

Atherosclerosis is recognised as an inflammatory disease, and new diagnostic tools are warranted to evaluate plaque inflammatory activity and risk of cardiovascular events. We investigated [18]-fluorodeoxyglucose (FDG) uptake in vulnerable carotid plaques visualised by positron emission tomography (PET). Uptake was correlated to quantitative gene expression of known markers of inflammation and plaque vulnerability.

METHODS

Ten patients with recent transient ischaemic attack and carotid artery stenosis (>50%) underwent combined FDG-PET and computed tomography angiography (CTA) the day before carotid endarterectomy. Plaque mRNA expression of the inflammatory cytokine interleukin 18 (IL-18), the macrophage-specific marker CD68 and the two proteinases, Cathepsin K and matrix metalloproteinase 9 (MMP-9), were quantified using real-time quantitative polymerase chain reaction.

RESULTS

Consistent up-regulation of CD68 (3.8-fold+/-0.9; mean+/-standard error), Cathepsin K (2.1-fold+/-0.5), MMP-9 (122-fold+/-65) and IL-18 (3.4-fold+/-0.7) were found in the plaques, compared to reference-artery specimens. The FDG uptake by plaques was strongly correlated with CD68 gene expression (r=0.71, P=0.02). Any correlations with Cathepsin K, MMP-9 or IL-18 gene expression were weaker.

CONCLUSIONS

FDG-PET uptake in carotid plaques is correlated to gene expression of CD68 and other molecular markers of inflammation and vulnerability.

Color Doppler, power Doppler and B-flow ultrasound in the assessment of ICA stenosis: Comparison with 64-MD-CT angiography

The purpose of this study is to investigate the diagnostic potential of color-coded Doppler sonography (CCDS), power-Doppler (PD) and B-flow ultrasound in assessing the degree of extracranial internal carotid artery (ICA) stenosis in comparison to CT-angiography (MD-CTA). Thirty-two consecutive patients referred for CTA with 41 ICA-stenoses were included in this prospective study. MD-CTA was performed using a 64 row scanner with a CTDIvol of 13.1 mGy/cm. In CTA, CCDS, PD and B-flow, the degree of stenosis was evaluated by the minimal intrastenotic diameter in comparison to the poststenotic diameter. Two radiologists performed a quantitative evaluation of the stenoses in consensus blinded to the results of ultrasound. These were correlated to CTA, CCDS, PD and B-flow, intraoperative findings and clinical follow-up. Grading of the stenoses in B-flow ultrasound outperformed the other techniques in terms of accuracy with a correlation coefficient to CTA of 0.88, while PD and CCDS measurements yield coefficients of 0.74 and 0.70. Bland-Altman analysis additionally shows a very little bias of the three US methods between 0.5 and 3.2 %. There is excellent correlation (coefficient 0.88, CI 0.77-0.93) with 64-MD-CTA and B-flow ultrasound in terms of accuracy for intrastenotic and poststenotic diameter. Duplex sonography is useful for screening purposes.

Modified technique of high-resolution ultrasonography of the normal cervical esophagus

BACKGROUND AND AIM

To study a modified technique of neck ultrasound for the visualization of cervical esophagus using a high-resolution and high frequency linear transducer in normal subjects.

METHODS

Consecutive control subjects were patients who underwent abdominal sonography for other diseases and had no past or current history of dysphagia or esophageal disorders. The thyroid gland was used as a transducer window to obtain images. We used a slightly flexed neck position with the head turned 45 degrees to the opposite side while scanning the neck on either side.

RESULTS

One-hundred subjects were scanned and their age range was 10-74 years (male:female ratio 1:1). In 36% of cases it was difficult to visualize the right lateral 2/3rd in the traditional scanning position of the neck. This improved to 2% with the modified neck position. All patients had the left window visualized with both neck positions. The transverse diameter, anterior-posterior diameter and wall thickness measures were all significantly greater with the modified technique. All patients tolerated the procedure with no reported discomfort.

CONCLUSIONS

This modified technique provides superior views of the cervical esophagus, particularly from the right window, in almost all patients. Normal parameters using ultrasound have now been established.

High-grade stenoses of the internal carotid artery: comparison of high-resolution contrast enhanced 3D MRA, duplex sonography and power Doppler imaging

PURPOSE

The objective of this study was to determine the agreement and diagnostic accuracy of high-resolution contrast enhanced magnetic resonance angiography (MRA) with integrated parallel acquisition techniques (iPAT), color coded duplex ultrasound (CCDS) and power Doppler ultrasound (PD) in the assessment of high-grade stenoses of the internal carotid artery (ICA).

METHODS

Forty-four patients with 52 known or suspected stenoses of the internal carotid artery (ICA) were included in this prospective study. High-resolution MRA scans with a spatial resolution of 0.9 mm x 0.7 mm x 0.9 mm were acquired with an iPAT acceleration factor of 2 on a 1.5T MR system (Sonata Maestro Class, Siemens Medical Solutions, Erlangen, Germany) with a head, neck and body coil. For the 3D-CE MRA a fast spoiled gradient echo sequence (FLASH) was used. To compensate for the inherent signal loss with parallel imaging, a 1M contrast agent (gadobutrol, Gadovist, Schering, Berlin, Germany) was used. Stenoses were quantified by two readers in consensus in cross-sectional area measurements and graded according to the NASCET criteria. Using color coded duplex ultrasound (CCDS) and power Doppler (PD; Logiq 9, GE), the stenoses were also graded by two readers in consensus according to the NASCET criteria from intra- and post-stenotic diameter measurements. The results of MRA, CCDS and PD were compared to intraoperative findings or to follow-up examinations.

RESULTS

High-resolution MRA allowed an excellent grading of vascular stenoses. In 70-90% degrees of stenosis there was an underestimation of the degree of stenosis in MRA as well as in CCDS. However, there was an overestimation of 90% stenoses in both MRA and CCDS. Pseudoocclusions with a lumen of less than one millimeter were occasionally rated as a complete occlusion in MRA.

CONCLUSION

A combination of MRA and duplex sonography seems reasonable for the accurate grading of stenoses and determination of distal stenoses downstream. However, the accuracy of duplex ultrasound depends on the examiner's experience.

Diagnostics and characterisation of preocclusive stenoses and occlusions of the internal carotid artery with B-flow

The purpose was to evaluate whether B-flow can improve the ultrasonographic diagnosis of preocclusive stenosis and occlusion of the internal carotid artery (ICA) compared with colour-coded Doppler and power Doppler. Ninety patients with occlusions or preocclusive stenoses of the ICA suspected by Doppler sonography were examined with B-flow in comparison with colour-coded Doppler sonography (CCDS), power Doppler (PD) and intra-arterial digital subtraction angiography (DSA). Intrastenotic flow detection and lengths of stenoses were the main criteria. Ulcerated plaques found by surgery in 42/90 patients were compared by ultrasonography (US). Diagnosis of ICA occlusion with CCDS, PD and B-flow was correct in all 42 cases. A preocclusive ICA stenosis in DSA was detected correctly in all 48/48 cases (100%) for B-flow, in 44/48 (92%) for PD and in 39/48 (81%) for CCDS. Surgical findings showed in 17/42 cases ulcerated plaques; 15/17 (89%) of these cases were detected with B-flow, 12/17 (71%) with PD, 10/17 (59%) with CCDS, and 8/17 (47%) with DSA. With B-flow the extent of stenosis was appraised more precisely than with PD and CCDS (P<0.0001). In conclusion, B-flow is a reliable method for preocclusive stenosis of the ICA with less intrastenotic flow artefacts. B-flow facilitates the characterization of plaque morphologies.

Potential Value of Poststroke Extracranial Arterial Blood Flow Volume in the Prediction of Stroke Functional Outcome

BACKGROUND AND PURPOSE

Cerebral vasoreactivity and collateral circulation are important protective mechanisms against cerebral ischemia. Previous studies suggest that the efficiency of these mechanisms can be reflected by extracranial arterial blood flow volume. Brain damage leading to neurological impairments can influence patients' functional recovery after stroke. This study attempted to explore the potential value of post stroke extracranial arterial blood flow volume in the prediction of stroke patients' functional outcome.

METHODS

We prospectively studied 362 consecutive patients who were hospitalized for recent acute strokes. All patients underwent extracranial arterial blood flow volume measurement of the carotid and vertebral arteries by color velocity imaging quantification within 3 days after admission. Their functional recovery was assessed 6 months after stroke. The effect of post stroke extracranial arterial blood flow volume on patients' functional outcome was tested by multivariate ordinal regression after controlling for other independent variables. Significance was at p<0.05.

RESULTS

Post stroke extracranial arterial blood flow volume together with age, pre-stroke modified Rankin scale, the National Institutes of Health Stroke Scale and diabetes mellitus had significant effects on the patients' 6-month functional outcome as measured by the modified Rankin scale after controlling for other independent variables (p<0.05).

CONCLUSIONS

Post stroke extracranial arterial blood flow volume is an independent outcome predictor. The graded predictive power of this parameter is potentially more superior than other outcome predictors by allowing classification of stroke outcome according to the degree of severity. A large prospective study is thus warranted to investigate its clinical value in the management of stroke patients.

Duplex sonography of retro-orbital and carotid arteries in patients with normal-tension glaucoma

PURPOSE

To evaluate retrobulbar and carotid arterial hemodynamics in patients with normal-tension glaucoma using Doppler sonography.

MATERIALS AND METHODS

Duplex sonography was performed in 41 patients with normal-tension glaucoma and 30 control subjects to evaluate resistance indices (RIs) in retro-orbital and carotid arteries. Mean values were compared using the independent t-test. The ratios of the RI in retro-orbital to RIs in the carotid arteries (CCA and ICA) and interocular and intercarotid differences in RI (DeltaRI) were also calculated.

RESULTS

Is in the central retinal (CRA) and temporal and nasal posterior ciliary arteries (TPCA and NPCA) were statistically significantly greater in glaucomatous eyes (p < 0.001). Plaque formation in carotid arteries without significant stenosis was noted in 12% of patients and 10% of control subjects. Ratios of RI of CRA or TPCA or NPCA to that of CCA and the ratios of RI of CRA or NPCA to that of ophthalmic arteries (OA) were significantly greater in glaucomatous eyes. We also found that ratios of the RI of CRA or TPCA or NPCA to that of ICA and the ratio of the RI of OA to CCA were nearly equal to 1 in both patients and control subjects. We found no significant difference between interocular and intercarotid DeltaRIs in patients and control subjects.

CONCLUSIONS

In patients with symmetric normal-tension glaucoma, duplex sonography showed an elevated RI in CRA and PCA. The Doppler evaluation of carotid arteries was useful.

Ultrasonographic confirmation of carotid artery atheromas diagnosed via panoramic radiography

BACKGROUND

Studies have shown that panoramic radiographs can capture images of calcified atheromas in the internal carotid artery (ICA) in some neurologically asymptomatic patients receiving routine dental care. However, the prevalence of these hemodynamically significant lesions--that is, those causing greater than 50 percent vessel lumen occlusion with the consequent heightened risk of stroke--has been evaluated rarely. The purpose of this study was to use Doppler ultrasonography (DUS) to determine the prevalence of large occlusive lesions detected initially via panoramic radiography. Aggressive medical and surgical interventions directed toward these large lesions have been shown to moderate the risk of stroke.

STUDY DESIGN

The authors analyzed the panoramic radiographs of 1,548 consecutively treated, neurologically asymptomatic dental patients who were 50 years or older. Those with presumptive atheromas underwent DUS for confirmation of the diagnosis and for determination of the degree of stenosis.

RESULTS

The radiographs of 65 patients (4.2 percent) showed at least one ICA atheroma. Thirty-eight patients had bilateral opacities and 27 had unilateral opacities. DUS evaluation of the 103 sides of the neck with a radiographically identified atheroma revealed that none of the ICAs were normal, 81 (79 percent) had less than 50 percent stenosis, 18 (17 percent) had 50 to 69 percent stenosis and four (4 percent) had 70 percent or greater stenosis. Four of the ICAs on the 27 sides without calcifications were deemed normal and 23 had less than 50 percent stenosis.

CONCLUSIONS

These results demonstrate that a subset of patients (15 [23 percent] of 65) with an occult atheroma discovered on panoramic radiography had significant (> 50 percent) levels of ICA stenosis.

CLINICAL IMPLICATIONS

Dentists should refer all patients with radiographically identified atheromas to a physician for confirmation of the diagnosis and a determination of the magnitude of disease, because antiatherogenic interventions have been shown to prevent a stroke.