Presence of external carotid artery plaque independently predicts mortality in patients without internal carotid artery atherosclerosis.

BACKGROUND: The presence of plaque in the external carotid artery (ECA) detected on carotid duplex ultrasound (CDU) is of unknown clinical significance and may not be reported in routine clinical practice. We hypothesize that ECA plaque in the absence of plaque in the other cervical vessels is a risk factor for increased all-cause mortality. OBJECTIVES: To determine the significance of ECA plaque on all-cause mortality in the absence of internal carotid artery (ICA) or common carotid artery (CCA) plaque. METHODS: We queried the Non-Invasive Vascular Laboratory database for all CDUs performed between 1 January 2005 and 31 December 2005. All images were reviewed for the presence of plaque. Studies were included if plaque was absent in both the CCA and the ICA. Chart review was performed to obtain demographic and clinical information. All-cause mortality was determined using the Social Security Death Index. RESULTS: A total of 500 patient studies met the inclusion criteria; 64 patients (12.8%) had plaque in one or both ECAs. There was no significant difference in age (mean 58.1 ± 14.8 years), race (82.5% white), or sex (64.4% male) between those with and without ECA plaque. There was a significant difference in all-cause mortality between patients with and without isolated ECA plaque after adjustment for age, sex, low-density lipoprotein cholesterol, smoking, hypertension, body mass index, and surgery within 30 days of CDU (adjusted hazard ratio 2.60, 95% CI 1.46-4.66, p<0.001). CONCLUSIONS: The presence of plaque isolated to the ECA is an independent predictor of all-cause mortality and may impart important prognostic information for patients referred for CDU.

The influence of obesity on the assessment of carotid intima-media thickness.

BACKGROUND: The assessment of carotid intima-media thickness (CIMT) may improve cardiovascular risk prediction. The optimal protocol for CIMT measurement is unclear. CIMT may be measured in the common carotid artery (CCA), carotid bifurcation (CB), and internal carotid artery (ICA), but measurements from CB and ICA are more difficult to obtain. We studied the influence of body mass index (BMI) and atheroma plaques on the capacity to obtain CIMT measurements at different carotid sites. METHODS: Using an automatic system, CIMT was measured in 700 subjects aged 45-75, in the near and far walls of CCA, CB, and ICA bilaterally. The presence of atheroma plaques, BMI and vascular risk factors were recorded. RESULTS: CIMT measurements in CCA were possible in all except one subject. It was not possible to obtain CIMT measurements at CB or ICA in 24.1% of normal weight and 58.8% of obese subjects. The likelihood of obtaining CIMT measurement at all carotid sites decreased as the BMI increased. Atheroma plaques in a carotid segment did not preclude CIMT measurement at this site. CONCLUSIONS: CIMT measurements in distal carotid segments are more challenging in obese subjects. Measuring CIMT at CCA remains feasible in obese subjects and should be the primary endpoint in these subjects. Nevertheless, CB and ICA measurements, when feasible, would improve risk classification.

Quantitative assessment of external carotid artery territory supply with modified vessel-encoded arterial spin-labeling.

BACKGROUND AND PURPOSE: In patients with carotid stenosis or occlusion, cerebral blood could be supplied through collateral pathways to improve regional blood flow and protect against ischemic events. The contribution of collaterals from the ICA can be assessed by depiction of vascular perfusion territories with ASL. However, so far there is no method available to evaluate the collateral perfusion territory from the ECA in MR imaging. In this study, we present a new labeling scheme based on VE-ASL to quantitatively assess the perfusion territory of the ECA. MATERIALS AND METHODS: A new labeling approach with a Hadamard encoding scheme was developed to label major arteries, especially the ECA. Twelve healthy subjects with normal cerebrovascular anatomy were examined to demonstrate their perfusion territories. Eight patients with carotid artery stenosis or occlusion were assessed before and after surgery to show changes of their collateral blood supply. RESULTS: The proposed method enables assessment of the perfusion territories of the ECA. Good agreement was found between the vascular territories and normal cerebrovascular anatomy in healthy subjects. For the patients with carotid stenosis or occlusion, our noninvasive results provided information on collateral flow comparable with that from DSA. Their collateral flows from the ECA, moreover, could be quantitatively estimated pre- and postoperatively. CONCLUSIONS: The modified approach has been validated by the consistency of collateral perfusion territories with cerebrovascular anatomy, and quantitative assessment of collaterals proved useful for assisting in evaluating therapeutic interventions.

Assessment of CE-MRA for the rapid detection of supra-aortic vascular disease.

BACKGROUND: Contrast-enhanced MR angiography (CE-MRA) using a combined head and neck coil permits non-invasive imaging of the vasculature from the aortic arch through to the Circle of Willis in less than 2 minutes. OBJECTIVE: To determine the accuracy of CE-MRA for the detection of vascular pathology, in particular vascular stenoses, using digital subtraction angiography (DSA) as the gold standard. METHODS: In a prospective study of 81 patients referred for DSA, CE-MRA and DSA studies were performed within 72 hours of each other. CE-MRA was performed on a 1.5 Tesla clinical MRI scanner using a five-channel neurovascular array (head and neck coil), with dynamic tracking of the IV gadolinium bolus. CE-MRAs and DSA films were read by two interventional neuroradiologists blinded to the clinical presentation of the patient. RESULTS: On DSA, there were 77 vascular stenoses > or =50% identified, 51 extracranial and 26 intracranial. The overall sensitivity of CE-MRA using the neurovascular array for the detection of vascular stenoses > or =50% was 57% (95% CI: 46 to 68%) with a specificity of 98% (97 to 99%). The sensitivity for the detection of extracranial vascular stenoses > or =50% was 82% (72 to 93%) with a specificity of 97% (96 to 98%). However, the sensitivity for the detection of intracranial vascular stenoses > or =50% was only 8% (0 to 18%), with a specificity of 99% (98 to 100%). CONCLUSIONS: At this stage Contrast-enhanced MR angiography using a neurovascular coil shows promise as a rapid, specific, and noninvasive screening method for extracranial vascular disease, but not for intracranial vascular disease.

Preoperative assessment of the carotid bifurcation. Can magnetic resonance angiography and duplex ultrasonography replace contrast arteriography?

BACKGROUND AND PURPOSE: Noninvasive studies are used with increasing frequency to assess the carotid bifurcation before endarterectomy. Therefore, assessment of their diagnostic accuracies is essential for appropriate patient management. We prospectively evaluate two noninvasive tests, magnetic resonance angiography (MRA) and duplex ultrasonography (DU), as potential replacements for contrast arteriography (CA). METHODS: A blinded comparison of three-dimensional time-of-flight (TOF) MRA, two-dimensional TOF MRA, and DU in 176 arteries was performed. CA was used as the standard of comparison. RESULTS: Three-dimensional TOF MRA had a sensitivity of 94%, a specificity of 85%, and an accuracy of 88% for the identification of 70% to 99% stenosis; two-dimensional TOF MRA had a sensitivity and specificity that were approximately 10% lower than those of three-dimensional TOF MRA. DU resulted in a sensitivity of 94%, a specificity of 83%, and an accuracy of 86%. Combining data from three-dimensional TOF MRA and DU, allowing for CA only for disparate results, yielded a sensitivity of 100%, a specificity of 91%, and an accuracy of 94% among concordant noninvasive tests, with CA required in 16% of arteries. MRA accurately differentiated 17 carotid occlusions from 16 high-grade (90% to 99%) stenoses, whereas with DU two patent arteries were identified as occluded and one occluded artery was identified as patent. CONCLUSIONS: Three-dimensional TOF MRA is the most accurate noninvasive test. Combined use of MRA and DU results in a marked increase in accuracy to a level that obviates the need for CA in a majority of patients.

Carotid bifurcation stenosis: a comparative study between MR angiography and duplex scanning with respect to digital subtraction angiography.

PURPOSE: This study compared sensitivity, specificity and diagnostic accuracy of Echoduplex and Magnetic Resonance Angiography (MRA) in the evaluation of carotid bifurcation stenosis. MATERIAL AND METHODS: Twenty-five patients with clinical signs suggestive for cerebrovascular insufficiency (CVI) were studied with Duplex scan, MRA and Digital Subtraction angiography (DSA). Gold standard was the angiographic examination. RESULTS: on equal value of sensitivity (80.5%), MRA showed 96% specificity versus 81% of Duplex scan, 89.4% diagnostic accuracy versus 80.9% for Duplex scan. As for stenosis over 31%, the value of sensitivity did not change i.e., 80.5%; MRA showed 100% specificity versus 97.1% for Duplex, 91.2% diagnostic accuracy versus 89.1% respectively. These values compared by the test for categorial analysis and correspondence analysis (p < 0.05) did not indicate any statistically significant difference. DISCUSSION: on the basis of our experience and as shown by current literature [2, 12] we can state that both MR-angiography and Duplex scan fail in quantifying correctly carotid stenosis with consequent over- and underestimation [3, 4]. However, they can be considered effective diagnostic procedures in a screening program [12, 16]; they are accurate, safe and accepted by the population. CONCLUSIONS: on the basis of the cost in planning the screening of a population at risk for CVI, Duplex scanning is still to be considered the elective procedure.

Non-invasive assessment of carotid arteries: a comparison of techniques used in two laboratories.

Fifty-one patients were examined non-invasively in two different laboratories and underwent angiography for carotid artery disease. Results of the two examinations and angiography were compared. In one laboratory continuous wave Doppler ultrasonography of the accessible extracranial arteries was used; in the other laboratory spectral analysis of the Doppler signals and angioscan imaging of the bifurcation was carried out. Accuracy of the two examinations (when compared with angiography) were similar for stenoses of more than 50%; spectral analysis and angioscan were better than continuous wave Doppler in detection of less than 50% stenoses.

[Sonographic assessment of tumorous infiltrations of the extracranial carotid artery]. / Sonographische Beurteilung tumoröser Infiltrationen der extrakraniellen A. carotis.

The role of sonography in evaluation of tumorous infiltrations of the wall of the cervical arteries is discussed upon 75 patients with histologically proved lymphnode metastasis. Direct signs for the infiltration--loss of the echogenic wall of the arteries and indirect signs--length and circumference of the tumor/vessel contact area are evaluated. In 9 patients the infiltrations were correctly diagnosed, 4 patients were false positive. The technic of the sonographic investigation and potential pitfalls are demonstrated. The role of other investigation modalities are discussed.