Diagnostic value of non-invasive imaging techniques in the detection of carotid artery stenosis: a systematic review

The purpose of the study was to evaluate the diagnostic performance of non- invasive imaging methods of detecting carotid artery stenosis in comparison to digital subtraction angiography (DSA) by undertaking a systematic review of the literature. The non-invasive methods reviewed include multislice computed tomography (MSCT) angiography, duplex ultrasound (US) and magnetic resonance (MR) angiography.A search of medical databases (PubMed, Medline, ScienceDirect, Proquest) of the English literature was performed and 22 studies with 68 comparisons were found to meet the selection criteria and included in our study. 5 studies were performed with MSCT angiography, 11 with duplex US and 13 with MR angiography. Both duplex US and MR angiography were studied in 7 out of 24 US and MR studies. The diagnostic value of each imaging modality was reviewed in terms of the sensitivity and specificity compared to DSA, which is regarded as the standard method.The mean sensitivity and specificity for MSCT angiography, duplex US and MR angiography were 88% (95% CI: 83%, 92%) and 90% (95% CI: 85%, 94%), 88% (95% CI: 81%, 94%) and 89% (95% CI: 85%, 94%), 94% (95% CI: 90%, 97%) and 89% (95% CI: 85%, 92%), respectively based on overall assessment. The evaluation showed that contrast-enhanced MR angiography has high diagnostic value for detection of more than 50% stenosis of carotid artery stenosis with mean sensitivity and specificity being 95% (95% CI: 92%, 98%) and 91% (95% CI: 86% 95%). When assessment was based on a combination of MR angiography and duplex US, the sensitivity reached the highest value of 98% (95% CI: 96%, 100%). This analysis indicates that MR angiography, especially contrast-enhanced MR angiography could be used as a reliable alternative modality to DSA in the detection of carotid artery stenosis

Grading of carotid artery stenosis with multidetector-row CT angiography: visual estimation or caliper measurements?

To assess the optimal method for grading carotid artery stenosis with computed tomographic angiography (CTA), we compared visual estimation to caliper measurements, and determined inter-observer variability and agreement relative to digital subtraction angiography (DSA). We included 46 patients with symptomatic carotid stenosis for whom CTA and DSA of 55 carotids was available. Stenosis quantification by CTA using visual estimation (CTAVE) (method 1) was compared with caliper measurements using subjectively optimized wide window settings (method 2) or predefined contrast-dependent narrow window settings (method 3). Measurements were independently performed by two radiologists and two residents. To determine accuracy and inter-observer variability, we calculated linear weighted kappa, performed a Bland-Altman analysis and calculated mean difference (bias) and standard deviation of differences (SDD). For inter-observer variability, kappa analysis was “very good” (0.85) for expert observers using CTAVE compared with “good” (0.61) for experts using DSA. Compared with DSA, method 1 led to overestimation (bias 5.8–8.0%, SDD 10.6–14.4), method 3 led to underestimation (bias −6.3 to −3.0%, SDD 13.0–18.1). Measurement variability between DSA and visual estimation on CTA (SDD 11.5) is close to the inter-observer variability of repeated measurements on DSA that we found in this study (SDD 11.6). For CTA of carotids, stenosis grading based on visual estimation provides better agreement to grading by DSA compared with stenosis grading based on caliper measurements

Prevalence of Asymptomatic Carotid Stenosis in Korea Based on Health Screening Population

We attempted to investigate the prevalence and risk factors of carotid artery stenosis in Korea. Twenty thousand seven hundred twelve individuals who underwent carotid artery ultrasonography for health screening between March 2005 and March 2010 were retrospectively evaluated. The population was divided into four groups, according to the degree of stenosis, as Group A, below 29%; Group B, 30% to 49%; Group C, 50% to 74%; Group D, above 75%. The medical records of the individuals were investigated, and Fisher's exact test, chi-square tests, Kruskal-Wallis tests and a binary logistic regression model were used for statistical analysis. The prevalence of carotid stenosis was Group B, 5.5%; Group C, 0.9%; Group D, 0.1%. Old age, male gender, hypertension, diabetes mellitus and ischemic heart disease were significantly higher in Groups C and D (P = 0.001, 0.001, 0.001, 0.048, and 0.001, respectively). Among the males aged over 65 yr, the prevalence of carotid stenosis ≥ 50% and ≥ 30% were 4.0% and 18.2%, respectively. Asymptomatic carotid stenosis is not uncommon in Korea. Carotid ultrasonography is necessary for people with above-listed risk factors

Carotid endarterectomy and carotid artery stenting utilization trends over time

<p>Abstract</p> <p>Background</p> <p>Carotid endarterectomy (CEA) has been the standard in atherosclerotic stroke prevention for over 2 decades. More recently, carotid artery stenting (CAS) has emerged as a less invasive alternative for revascularization. The purpose of this study was to investigate whether an increase in stenting parallels a decrease in endarterectomy, if there are specific patient factors that influence one intervention over the other, and how these factors may have changed over time.</p> <p>Methods</p> <p>Using a nationally representative sample of US hospital discharge records, data on CEA and CAS procedures performed from 1998 to 2008 were obtained. In total, 253,651 cases of CEA and CAS were investigated for trends in utilization over time. The specific data elements of age, gender, payer source, and race were analyzed for change over the study period, and their association with type of intervention was examined by multiple logistic regression analysis.</p> <p>Results</p> <p>Rates of intervention decreased from 1998 to 2008 (P < 0.0001). Throughout the study period, endarterectomy was the much more widely employed procedure. Its use displayed a significant downward trend (P < 0.0001), with the lowest rates of intervention occurring in 2007. In contrast, carotid artery stenting displayed a significant increase in use over the study period (P < 0.0001), with the highest intervention rates occurring in 2006. Among the specific patient factors analyzed that may have altered utilization of CEA and CAS over time, the proportion of white patients who received intervention decreased significantly (P < 0.0001). In multivariate modeling, increased age, male gender, white race, and earlier in the study period were significant positive predictors of CEA use.</p> <p>Conclusions</p> <p>Rates of carotid revascularization have decreased over time, although this has been the result of a reduction in CEA despite an overall increase in CAS. Among the specific patient factors analyzed, age, gender, race, and time were significantly associated with the utilization of these two interventions.</p

CT Angiography is Cost-Effective for Confirmation of Internal Carotid Artery Occlusions

BACKGROUND AND PURPOSE While sensitive to internal carotid artery (ICA) occlusion, carotid ultrasound can produce false-positive results. CT angiography (CTA) has a high specificity for ICA occlusion and is safer and cheaper than catheter angiography, although less accurate. We determined the cost-effectiveness of CTA versus catheter angiography for confirming an ICA occlusion first suggested by carotid ultrasound. METHODS A Markov decision-analytic model was constructed to estimate the cost-effectiveness of CTA compared with catheter angiography in a hypothetical cohort of symptomatic patients with a screening examination consistent with an ICA occlusion. Costs in 2004 dollars were estimated from Medicare reimbursement. Effectiveness was measured in quality-adjusted life years. RESULTS The 2-year cost in the CTA scenario was $9,178, and for catheter angiography,$11,531, consistent with a $2,353 cost-savings per person for CTA. CTA resulted in accrual of 1.83 quality-adjusted life years while catheter angiography resulted in 1.82 quality-adjusted life years. CTA was less costly and marginally more effective than catheter angiography. In sensitivity analyses, when CTA sensitivity and specificity were allowed to vary across a plausible range, CTA remained cost-effective. CONCLUSIONS After screening examination has suggested an ICA occlusion, confirmatory testing with CTA provides similar effectiveness to catheter angiography and is less costly. J Neuroimaging 2008;18:355–359.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73651/1/j.1552-6569.2007.00216.x.pd

Tissue Doppler imaging of carotid plaque wall motion: a pilot study

BACKGROUND: Studies suggest the physical and mechanical properties of vessel walls and plaque may be of clinical value in the diagnosis and treatment of cardiovascular atherosclerotic disease. The purpose of this pilot study was to investigate the potential clinical application of ultrasound Tissue Doppler Imaging (TDI) of Arterial Wall Motion (AWM) and to quantify simple wall motion indices in normal and diseased carotid arteries. METHODS: 224 normal and diseased carotid arteries (0–100% stenoses) were imaged in 126 patients (age 25–88 years, mean 68 ± 11). Longitudinal sections of the carotid bifurcation were imaged using a Philips HDI5000 scanner and L12-5 probe under optimized TDI settings. Temporal and spatial AWMs were analyzed to evaluate the vessel wall displacements and spatial gradients at peak systole averaged over 5 cardiac cycles. RESULTS: AWM data were successfully extracted in 91% of cases. Within the carotid bifurcation/plaque region, the maximum wall dilation at peak systole ranged from -100 to 750 microns, mean 335 ± 138 microns. Maximum wall dilation spatial gradients ranged 0–0.49, mean 0.14 ± 0.08. The AWM parameters showed a wide variation and had poor correlation with stenoses severity. Case studies illustrated a variety of pertinent qualitative and quantitative wall motion features related to the biophysics of arterial disease. CONCLUSION: Our clinical experience, using a challenging but realistic imaging protocol, suggests the use of simple quantitative AWM measures may have limitations due to high variability. Despite this, pertinent features of AWM in normal and diseased arteries demonstrate the potential clinical benefit of the biomechanical information provided by TDI