A three-dimensional ultrasonographic quantitative analysis of non-ulcerated carotid plaque morphology in symptomatic and asymptomatic carotid stenosis

Three-dimensional ultrasonographic evaluation of carotid artery plaque surface irregularity

INTRODUCTION

The aim of this study was to evaluate 3-dimensional (3D) ultrasonography (US) in determining the surface irregularity of carotid artery plaques.

MATERIAL AND METHODS

This study included 50 patients (20 females and 30 males) aged between 56 and 82 years with plaques in the carotid artery which were detected during routine neck ultrasound. Simultaneously these cases were evaluated in terms of plaque echogenicities and surface characteristics with 2D and 3D US.

RESULTS

3D imaging was successfully performed in 45 of the 50 cases and the technical success rate was 90%. A single plaque was detected in 64.4% of the patients, with the remaining 35.6% having more than one plaque. The lengths of the plaques ranged from 2 to 12 mm (mean: 3.98 ±1.70 mm); the widths ranged from 1.8 to 3.2 mm (mean: 2.11 ±0.37 mm). No significant difference was found between 2D and 3D plaque echo-structures (observer 1, p = 0.317; observer 2, p = 0.276), but there were significant differences between 2D and 3D plaque surface irregularities (observer 1, p = 0.002; observer 2, p = 0.004). The inter-observer agreement on 2D and 3D plaque echo-structure and surface irregularity was very good (k coefficients were 0.89 and 0.83, respectively, for echo-structure, and 0.91 and 0.95, respectively, for surface irregularity).

CONCLUSIONS

The present study shows that 3D US examination is a valuable non-invasive method for investigation of surface irregularity of carotid artery plaques.

Ultrasound assessment of carotid arteries: Current concepts, methodologies, diagnostic criteria, and technological advancements

Following cardiac disease and cancer, stroke continues to be the third leading cause of death and disability due to chronic disease in the developed world. Appropriate screening tools are integral to early detection and prevention of major cardiovascular events. In a carotid artery, the presence of increased intima-media thickness, plaque, or stenosis is associated with increased risk of a transient ischemic attack or a stroke. Carotid artery ultrasound remains a long-standing and reliable tool in the current armamentarium of diagnostic modalities used to assess vascular morbidity at an early stage. The procedure has, over the last two decades, undergone considerable upgrades in technology, approach, and utility. This review examines in detail the current state and usage of this integrally important means of extracranial cerebrovascular assessment.

Observer performance in characterization of carotid plaque texture and surface characteristics with 3D versus 2D ultrasound

OBJECTIVE

To determine the reproducibility of three-dimensional (3D) ultrasound (US) over two-dimensional (2D) US in characterizing atherosclerotic carotid plaques using inter- and intra-observer agreement metrics.

METHODS

A Total of 51 patients with 105 carotid artery plaques were screened using 3D and 2D US probes attached to the same US scanner. Two independent observers characterized the plaques based on the morphological features namely echotexture, echogenicity and surface characteristics. The scores assigned to each morphological feature were used to determine intra- and inter-observer performance. The level of agreement was measured using Kappa coefficient.

RESULTS

The first observer with 2D US showed fair (k=0.4-0.59) and very strong (k>0.8) with 3D US intra-observer agreements using three morphological features. The second observer indicated moderate strong (k=0.6-0.79) with 2D US and very strong with 3D US (k>0.8) intra-observer performances. Moderate strong (k=0.6-0.79) and very strong (k>0.8) inter-observer agreements were reported with 2D US and 3D US respectively. The results with 2D and 3D US were correlated 62% using only echotexture and 56% using surface morphology coupled with echogenicity. 3D US gave a lower score than 2D 71% of the time (p=0.005) in disagreement cases.

CONCLUSION

High reproducibility in carotid plaque characterization was obtained using 3D US rather than 2D US. Hence, it can be a preferred imaging modality in routine or follow up plaque screening of patients with carotid artery disease.

Reproducibility of two different methods for performing mean gray value evaluation of cyst content in endometriomas using VOCAL

OBJECTIVE

To compare two different methods (manual sampling of the entire cyst and semi-automated spherical sampling from the central part of the cyst) for calculating the mean gray value (MGV) from the cystic content in endometriomas using virtual organ computer-aided analysis (VOCAL).

METHODS

Forty-one volumes from histologically confirmed endometriomas were retrieved from our database and the volumes were analyzed to compare the MGVs obtained via the two modalities. In addition, to evaluate the reproducibility in a sample of 20 volumes, two different observers calculated the MGV from cyst content using VOCAL software. For each method, each examiner analyzed the volumes twice, 3 weeks apart, for assessment of intra-observer agreement. First, manual sampling of the internal contour of all the cysts was performed, and 1 week later semi-automated 2-cm sphere sampling from the central part of the cyst was carried out. In addition, the observers recorded the time spent performing each analysis. Inter- and intra-observer reproducibility was evaluated for each method using intra-class correlation coefficients (ICC).

RESULTS

There was no difference in the mean MGV between manual sampling (22.211 ± 7.541) and the semi-automated modality of sampling (23.840 ± 8.621, p = 0.439). The correlation between manual and semi-automated sampling measurement was high (r = 0.92). According to the ICCs, there was no significant difference in interobserver reliability between manual sampling (0.931; 95 % CI, 0.824-0.973) and the semi-automated modality of sampling (0.924; 95 % CI, 0.809-0.970). Intra-observer reproducibility for both examiners was good (ICC > 0.94). Semi-automated measurements were obtained faster than those obtained by manual evaluation (p = 0.0001 for observer 1 and p = 0.083 for observer 2).

CONCLUSIONS

Both methods seem to be reliable, but the semi-automated method using the sphere should be preferred because it is a less time-consuming procedure.

General principles of carotid Doppler ultrasonography

Carotid Doppler ultrasonography is a popular tool for evaluating atherosclerosis of the carotid artery. Its two-dimensional gray scale can be used for measuring the intima-media thickness, which is very good biomarker for atherosclerosis and can aid in plaque characterization. The plaque morphology is related to the risk of stroke. The ulceration of plaque is also known as one of the strong predictors of future embolic event risk. Color Doppler ultrasonography and pulse Doppler ultrasonography have been used for detecting carotid artery stenosis. Doppler ultrasonography has unique physical properties. The operator should be familiar with the physics and other parameters of Doppler ultrasonography to perform optimal Doppler ultrasonography studies.

Tissue characterization using mean gray value analysis in deep infiltrating endometriosis

OBJECTIVES

To investigate differences in tissue characterization using three-dimensional sonographic mean gray value (MGV) between retrocervical and rectosigmoid deeply infiltrating endometriosis, and to assess intra- and interobserver concordance in MGV quantification.

METHODS

In this retrospective study, stored ultrasound volumes from 50 premenopausal women (mean age, 32 years) with 57 histologically confirmed nodules of deep endometriosis were retrieved from our database for analysis. A single experienced operator had acquired all volumes. For each nodule, the MGV was evaluated using virtual organ computer-aided analysis (VOCAL) software with semiautomated sphere-sampling (1 cm3) from the central part of the nodule. In these patients the MGV was also quantified from the myometrium of the fundal part of the uterus. In addition, two observers calculated the MGV in a subset of 24 volumes in order to quantify inter- and intraobserver agreement using intraclass correlation coefficients (ICC).

RESULTS

Mean MGV was significantly higher in rectosigmoid nodules (n = 34) than in nodules with a retrocervical location (n = 23) (23.863 vs. 17.705; P < 0.001). MGV of the myometrium was significantly higher in comparison with that of nodules in both locations (P < 0.001 for both). Intra- and interobserver measurement reproducibility was excellent (ICC > 0.95).

CONCLUSIONS

Retrocervical and rectosigmoid endometriotic nodules display significantly different MGVs. Measurement of MGV is highly reproducible and its clinical value in the diagnosis and assessment of distribution of deep endometriosis should be assessed in future studies.

Association of ultrasonographic parameters with subclinical white-matter hyperintensities in hypertensive patients

Background and Purpose. Cerebral white matter hyperintensities (WMHs) are regarded as typical MRI expressions of small-vessel disease (SVD) and are common in hypertensive patients. Hypertension induces pathologic changes in macrocirculation and in microcirculation. Changes in microcirculation may lead to SVD of brain and consequently to hypertensive end-organ damage. This damage is regarded the result of interactions between the macrovascular and microvascular levels. We sought to investigate the association of cerebral WMHs with ultrasonographic parameters of cerebral macrocirculation evaluated by carotid duplex ultrasound (CDU) and transcranial doppler (TCD). Subjects and Methods. The study was prospective, cross-sectional and consecutive and included hypertensive patients with brain MRI with WMHs. Patients underwent CDU and TCD. The clinical variables recorded were demographic characteristics (age, gender, race) and vascular risk factors (hypertension, diabetic mellitus, hypercholesterolemia, current smoking, and body mass index). Excluded from the study were patients with history of clinical stroke (including lacunar stroke and hemorrhagic) or transient ischemic attack (either hemispheric or ocular), hemodynamically significant (>50%) extra- or intracranial stenosis, potential sources of cardioembolism, and absent transtemporal windows. WMHs were quantified with the use of a semiquantitative visual rating method. Ultrasound parameters investigated were (1) common carotid artery (CCA) diameter and intima-media thickness, (2) blood flow velocity in the CCA and internal carotid artery (ICA), and (3) blood flow velocity and pulsatility index of middle cerebral artery (MCA). Results. A total of 52 patients fulfilled the study inclusion criteria (mean age 71.4 ± 4.5 years, 54% men, median WMH-score: 20). The only two ultrasound parameters that were independently associated with WMH score in multivariate linear regression models adjusting for demographic characteristics and vascular risk factors were increased mean common carotid artery (CCA) diameter (beta = 0.784, SE = 0.272, P = 0.006, R² = 23.9%) and increased middle cerebral artery pulsatility index (MCA-PI; beta = 0.262, SE = 0.110, P = 0.025, R² = 9.0%). Among all ultrasound parameters the highest AUC (areas under the receiver operating characteristic curve) were documented for MCA-PI (AUC = 0.82, 95% CI = 0.68−0.95, P < 0.001) and mean CCA diameter (AUC = 0.80, 95% CI = 0.67−0.92, P < 0.001). Conclusions. Our study showed that in hypertensive individuals with brain SVD the extent of structural changes in cerebral microcirculation as reflected by WMHs burden is associated with the following ultrasound parameters of cerebral macrocirculation: CCA diameter and MCA-PI.

Prevalence of symptomatic intracranial atherosclerosis in Caucasians: a prospective, multicenter, transcranial Doppler study

BACKGROUND

There are limited data available regarding symptomatic intracranial atherosclerosis (SIA) prevalence in Caucasians. We sought to investigate SIA prevalence among Caucasian patients hospitalized with acute cerebral ischemia (ACI) in a prospective, multicenter Transcranial Doppler sonography (TCD) study.

METHODS

Consecutive patients with ACI were prospectively evaluated with TCD over a 24-month-period. The previously validated criteria of SONIA trial were used for detection of >50% intracranial stenosis with TCD. Brain angiography was performed to confirm the diagnosis in cases with abnormal TCD findings. SIA was diagnosed when there was evidence of a cerebral infarction in the territory of the stenotic artery (identified by TCD and confirmed by Magnetic resonance angiography [MRA]/Computed tomography angiography [CTA]).

RESULTS

A total of 467 consecutive patients with ACI (60.4% men, mean age 58 ± 14 years) were evaluated. SIA was documented in 43 patients (9.2%; 95%CI: 6.9%-12.2%). The most common SIA location was M1MCA (34.9%) followed by TICA (18.8%). Diabetes mellitus (OR: 4.25, 95%CI: 2.18-8.26; P < .001) and hypertension (OR: 2.41, 95%CI: 1.02-5.67; P = .045) were independently associated with SIA on multivariate models adjusting for potential confounders.

CONCLUSIONS

SIA was identified in almost 10% of patients admitted with symptoms of ACI. These preliminary findings support further collaborative initiatives among stroke physicians to increase the yield of SIA detection in Caucasian patients with ACI.

Noninvasive detection of intimal xanthoma using combined ultrasound, strain rate and photoacoustic imaging

BACKGROUND AND MOTIVATION

The structure, composition and mechanics of carotid artery are good indicators of early progressive atherosclerotic lesions. The combination of three imaging modalities (ultrasound, strain rate and photoacoustic imaging) which could provide corroborative information about the named arterial properties could enhance the characterization of intimal xanthoma.

METHODS

The experiments were performed using a New Zealand white rabbit model of atherosclerosis. The aorta excised from an atherosclerotic rabbit was scanned ex vivo using the three imaging techniques: (1) ultrasound imaging of the longitudinal section: standard ultrasound B-mode (74Hz frame rate); (2) strain rate imaging: the artery was flushed with blood and a 1.5Hz physiologic pulsation was induced, while the ultrasound data were recorded at higher frame rate (296Hz); (3) photoacoustic imaging: the artery was irradiated with nanosecond pulsed laser light of low fluence in the 1210-1230nm wavelength range and the photoacoustic data was recorded at 10Hz frame rate. Post processing algorithms based on cross-correlation and optical absorption variation were implemented to derive strain rate and spectroscopic photoacoustic images, respectively.

RESULTS

Based on the spatio-temporal variation in displacement of different regions within the arterial wall, strain rate imaging reveals differences in tissue mechanical properties. Additionally, spectroscopic photoacoustic imaging can spatially resolve the optical absorption properties of arterial tissue and identify the location of lipid pools.

CONCLUSIONS

The study demonstrates that ultrasound, strain rate and photoacoustic imaging can be used to simultaneously evaluate the structure, the mechanics and the composition of atherosclerotic lesions to improve the assessment of plaque vulnerability.

Modern ultrasound methods and atherosclerosis assessment in patients with familial hypercholesterolemia

Familial hypercholesterolemia (FHCH) is characterised by early atherosclerosis development and its fast progression. The prevalence of FHCH inRussiahas been increasing, therefore, it is important to evaluate the potential of various methods for atherosclerosis diagnostics. Arterial ultrasound is an informative, accessible, and safe method for evaluating atherosclerotic vascular changes. The modern ultrasound methods allow describing vascular wall status in detail, including qualitative and quantitative characteristics of its structure and function. At the same time, most ultrasound characteristics of arterial wall are used in research settings or are under development, and not implemented into clinical practice. The most promising parameters, applicable for clinical use in FHCH patients, simultaneously describe atherosclerosis severity and its localization, such as total plaque height, ankle-brachial index, and plaque number.

Common carotid intima media thickness as a marker of clinical severity in patients with symptomatic extracranial carotid artery stenosis

OBJECTIVES

Increased common carotid artery intima-media thickness (CCA-IMT) is a risk factor for ischemic stroke and especially large vessel atherothrombotic infarction. However, the potential association of stroke severity with the intima-media thickening has not been previously studied. We sought to investigate the association between CCA-IMT and clinical severity of ischemic stroke in patients with symptomatic extracranial carotid artery stenosis (SCAS).

PATIENTS AND METHODS

Consecutive patients with acute, first-ever ischemic stroke and SCAS (50%-99%) were prospectively evaluated. All subjects underwent IMT measurements at the far wall of CCA. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS) on hospital admission and Barthel Ambulatory Index (BI) at hospital discharge.

RESULTS

CCA-IMT was strongly correlated to NIH (Spearman's correlation coefficient: r=0.546, p<0.001) and BI (r=-0.450, p<0.001) in the study population (n=102). A 0.1mm increase in CCA-IMT was independently associated with increasing NIHSS-scores on hospital admission (beta: 0.510; p<0.001) and decreasing BI-scores at hospital discharge (beta: -0.483; p<0.001) even after adjustment for demographic characteristics and cardiovascular risk factors. After including baseline stroke severity (NIHSS) in the multivariate linear regressions models evaluating early functional outcome, only NIHSS was independently related to BI (standardized linear regression coefficient: -0.776, p<0.001), while the initial association between IMT and BI did not retain its statistical significance (beta: -0.074, p=0.276).

CONCLUSIONS

Increased CCA-IMT is independently associated with more severe stroke on admission in patients with SCAS.