Study of atheromatous stenoses of carotid bifurcations by Doppler ultrasound, spiral angio-MRI, magnetic resonance angiography and comparison with arteriography

PURPOSE: To evaluate Doppler ultrasound (US), Helical CT, Magnetic Resonance (MR) angiography in the detection of carotid bifurcation atherosclerotic disease and comparison with angiography. MATERIALS AND METHODS: After a Doppler US procedure, 56 carotid bifurcations were included (symptomatic stenosis greater than 60% or asymptomatic stenosis greater than 30%). Helical CT, MR angiography and selective arteriography were performed. Stenosis were measured with NASCET criteria. Sensitivity and specificity were calculated and compared to arteriographics findings for each procedure and each grade of stenosis. RESULTS: Helical CT and MR angiography had their best sensitivity in grade 3 (70-99%), 92%, 100% respectively, their specificity was identical (91%). All the occlusions were depicted by the three procedures. CONCLUSION: Association of Doppler US and MR angiography may replace in the future selective angiography in the evaluation of extracranial atherosclerotic disease. Arteriography would be performed only in case of discordance between these two procedures.     

Race and sex differences in the distribution of cerebral atherosclerosis

BACKGROUND AND PURPOSE: The purpose of this study was to assess the influence of race, sex, and other risk factors on the location of atherosclerotic occlusive lesions in cerebral vessels. Previous angiographic studies of patients with stroke or transient ischemic attack (TIA) suggest that extracranial atherosclerosis is more common in whites and intracranial disease is more common in blacks. Noninvasive techniques such as duplex ultrasound, transcranial Doppler (TCD), and magnetic resonance angiography (MRA) allow vascular assessment of a more representative proportion of patients than does conventional angiography alone. METHODS: Consecutive patients evaluated at a community hospital for stroke or TIA over a 2-year period were reviewed. Lesions were defined as a 50% or greater atherosclerotic stenosis by angiography, duplex ultrasound, or TCD, or a moderate stenosis by MRA. RESULTS: Whites were more likely than blacks to have extracranial carotid artery lesions (33% versus 15%, P = .001), but the proportion of patients with intracranial lesions was similar (24% versus 22%). Men were more likely to have intracranial lesions than women (29% versus 14%, P = .03). When multivariate logistic regression analysis was used, white race was the only predictor for extracranial carotid artery lesions, and male sex was the only predictor for intracranial lesions. The cause of stroke/TIA was extracranial carotid artery disease in 8% and intracranial disease in 8% of all patients in the study. CONCLUSIONS: The distribution of cerebral atherosclerosis is influenced by race and sex but not by other vascular risk factors. In our patient population, intracranial disease is as common a cause of cerebral ischemia as extracranial carotid disease.     

Impaired clearance of emboli (washout) is an important link between hypoperfusion, embolism, and ischemic stroke

OBJECTIVE: To explore the relationship between hypoperfusion, embolism, and brain infarction. DESIGN: We studied 4 situations in which brain infarction is related to hypoperfusion: extracranial and intracranial occlusive vascular disease, reduced functional vascular reserve in patients with carotid artery occlusive disease, reduced collateral blood flow in patients given thrombolytic treatment, and cardiac surgery. We reviewed results of emboli monitoring using transcranial Doppler ultrasonography. RESULTS: Hypoperfusion is strongly linked to brain ischemia and infarction. The evidence includes close correlation of (1) the severity of arterial stenosis with brain infarction; (2) impaired functional blood flow reserve in patients with carotid artery disease and subsequent brain infarction; (3) reduced collateral blood flow with poor prognosis after thrombolysis; and (4) stroke-related neurologic deficits after cardiac surgery to hypoperfusion during surgery. Microembolization is common in patients with severe symptomatic carotid artery stenosis and during and after cardiac surgery. CONCLUSIONS: Hypoperfusion and embolism often coexist and their pathophysiological features are interactive. Arterial lumenal narrowing and endothelial abnormalities stimulate clot formation and subsequent embolization. Reduced perfusion limits the ability of the bloodstream to clear or wash out emboli and microemboli and reduces available blood flow to regions rendered ischemic by emboli that block supply arteries. The brain border zones are a favored destination for microemboli that are not cleared. We posit that impaired washout is an important but neglected concept that intertwines hypoperfusion, embolization, and brain infarction.     

Power Doppler imaging of carotid artery stenosis. Comparison with color Doppler flow imaging and angiography

BACKGROUND AND PURPOSE: Power Doppler imaging (PDI) is a new sonographic technique that has recently been introduced for vascular application. Since the technical principles of PDI may provide increased sensitivity to visualize the continuity of blood flow in arterial stenoses, we investigated the diagnostic significance of PDI and the intermethod relationship for the measurement and classification of internal carotid artery (ICA) stenosis in comparison with both color Doppler flow imaging (CDFI) and angiography. METHODS: One hundred patients with a total of 128 ICA stenoses (50% to 69%, n = 37; 70% to 79%, n = 27; 80% to 99%, n = 64) and 12 ICA occlusions were consecutively investigated by means of PDI, CDFI, and intra-arterial angiography (n = 48). Reduction of the intrastenotic lumen was measured on longitudinal and transverse views of PDI and CDFI for the calculation of the degree of diameter and area stenosis, respectively. Angiographic stenosis was determined with the use of the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trial (ECST), and common carotid (CC) methods. RESULTS: PDI provided significantly more excellent or good (92% versus 79%; P < .01) displays of the intrastenotic lumen than CDFI, particularly in complicated high-grade stenosis. While linear regression analysis demonstrated a high overall correlation between PDI and CDFI for diameter (r = .88; P < .001) and area stenosis (r = .79; P < .001), categorization of ICA stenosis revealed best agreement for 80% to 99% area stenoses. Since angiography frequently either underclassified (NASCET method) or overclassified (ECST, CC methods) the degree of ICA stenosis in comparison to both PDI and CDFI, the sonographic-angiographic correlation was only moderate (regression coefficients ranged from .62 to .70; P < .001). CONCLUSIONS: PDI further improves the assessment of ICA stenosis by providing better visualization of the stenotic vascular lumen than CDFI. Sonographic imaging of the stenotic plaque on both PDI and CDFI provided a direct measurement of the local degree of stenosis, while the angiographic grade of stenosis essentially depended on the method used for evaluation.     

Collateral blood supply through the ophthalmic artery: a steal phenomenon analyzed by color Doppler imaging

OBJECTIVE: This study aimed to evaluate the retrobulbar circulatory effects of reversed ophthalmic artery flow (ROAF) on the ophthalmic artery branches by means of color Doppler imaging. DESIGN: The design was a case-controlled study. PARTICIPANTS: Among 56 consecutive patients with severe (>70% stenosis) occlusive carotid artery disease, 15 patients (26.8%) with ROAF were identified. The control group consisted of 15 patients with similar degrees of carotid artery stenosis and forward ophthalmic artery flow. INTERVENTION: Arteriography and measurement of the retrobulbar hemodynamic parameters with color Doppler imaging were performed. MAIN OUTCOME MEASURES: Blood flow velocities and resistive index in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. RESULTS: Arteriography confirmed the diagnosis of ROAF in all 15 patients. There was no patient with ROAF diagnosed by arteriography and not diagnosed by color Doppler imaging. The frequency of bilateral severe occlusive carotid artery disease was significantly higher in the ROAF group (40%) compared to the control group (6.6%) (P = 0.04). Patients with ROAF showed significantly reduced vascular resistance in the ophthalmic artery (P = 0.03), higher vascular resistance, and lower blood flow velocities in the central retinal and temporal short posterior ciliary arteries (P < 0.05). CONCLUSION: This study suggests that patients with ROAF show a steal phenomenon, characterized by a shunt to the low-resistance intracranial circuit and reduction of retrobulbar blood flow.     

Profile of anti-stratum corneum autoantibodies in patients with aural cholesteatoma

A study was performed to evaluate immediate changes in carotid artery blood flow after carotid endarterectomy using a Doppler ultrasonographic flowmeter. Forty-seven consecutive patients aged 49-78 (median 64) years with symptomatic internal carotid artery (ICA) stenosis underwent carotid endarterectomy. Volume flow, resistance and pulsatility index were measured in the common carotid artery (CCA) and ICA both before and after operation. ICA flow increased by 54 per cent (P < 0.01) and resistance decreased by 58 per cent (P = 0.01). CCA flow rose by 17 per cent (P = 0.1) and resistance fell by 21 per cent (P = 0.02). The pulsatility index did not change significantly. The Doppler ultrasonographic flowmeter offers a simple, non-invasive and convenient means of improving understanding of the immediate haemodynamic effects of carotid endarterectomy. It is useful in everyday practice to confirm the adequacy of endarterectomy, particularly in the absence of other methods of quality control. Duplex ultrasonography might still be necessary after surgery if the flowmeter does not demonstrate an increase in flow compared with the preoperative value.     

Correlation of cine MR velocity measurements in the internal carotid artery with collateral flow in the circle of Willis: preliminary study

The velocity-phase relationship intrinsic to phase-contrast magnetic resonance (MR) angiography permits the quantitative and qualitative assessment of blood flow. The ability to measure velocity and vessel cross-sectional area allows noninvasive assessment of volume flow rate (VFR) in the internal carotid artery (ICA). Phase-contrast techniques also demonstrate flow direction. Using two-dimensional cine phase-contrast angiography, the authors evaluated VFR in the ICA and collateral flow about the circle of Willis in 15 patients with ischemic neurologic symptoms. The VFR in each carotid artery was correlated with the degree of stenosis and presence or absence of abnormal circle of Willis collateral flow. There was a correlation between a decrease in VFR and abnormal circle of Willis collateral flow. In addition, a correlation between severe stenosis and a decrease in VFR was found. In patients with ischemic neurologic symptoms without severe stenosis (< 70% diameter stenosis), no decrease in VFR was seen. It is hoped that flow quantification and directional flow imaging with phase-contrast angiography will help further characterize carotid artery occlusive disease by enabling assessment of VFR changes associated with ischemic neurologic symptoms. This study also supports the hypothesis that two mechanisms--hemodynamic and embolic--play a role in ischemic neurologic symptoms.     

Risk factors for ectopic pregnancy in assisted reproduction

BACKGROUND AND PURPOSE: The estimated prevalence of intracranial atherosclerotic disease (IAD) in patients with stenosis of the extracranial internal carotid artery (ICA) varies between 20% and 50%. The benefits of carotid endarterectomy (CE) in patients with both IAD and symptomatic extracranial ICA stenosis are uncertain. METHODS: The association between IAD and other vascular risk factors and with the risk of stroke at 3 years were studied in patients with symptomatic extracranial ICA stenosis who participated in the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Since the NASCET protocol excluded severe IAD, only a modest number of patients in this category could be studied. RESULTS: IAD was observed in one third of the patients. In medically treated patients, the relative risk of stroke associated with IAD varied from 1.3 (95% CI, 0.9 to 1.9) with extracranial ICA stenosis of <50% to 1.8 (95% CI, 1.1 to 3.2) with 85% to 99% ICA stenosis. In contrast, IAD did not affect the risk of stroke among surgically treated patients. To prevent 1 stroke ipsilateral to the symptomatic ICA stenosis over 3 years in patients who have also IAD, 12 patients with 50% to 69%, 5 patients with 70% to 84%, and 3 patients with 85% to 99% ICA stenosis have to undergo CE. In patients without IAD these numbers are 26, 7, and 6, respectively. CONCLUSIONS: IAD is an independent risk factor for subsequent stroke in medically treated patients with symptomatic ICA stenosis. CE reduces this risk. The additional risk imposed by IAD in medically treated patients enhances the value of CE in patients with moderate symptomatic extracranial ICA stenosis. Detection of IAD, requiring angiography, is an important prelude to planning CE in symptomatic patients with moderate extracranial ICA stenosis.     

Clinical findings and hemodynamic changes associated with severe occlusive carotid artery disease

OBJECTIVE: The purpose of the study was to evaluate the ophthalmologic findings and to analyze the retrobulbar hemodynamics of patients with severe (greater than 70% stenosis) occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: A case-controlled study. PARTICIPANTS: Fifty-six consecutive patients with severe OCAD and an age- and sex-matched control group consisting of 56 healthy patients without OCAD were studied. INTERVENTION: All 112 patients underwent a complete ophthalmologic examination. Color Doppler imaging of both orbits was performed by one masked investigator. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and the resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters measured in patients with severe OCAD with those obtained in the control group. The hemodynamic parameters of patients with asymmetric OCAD (stenosis > 70% in one internal carotid artery and stenosis < 50% in the contralateral artery) were also compared. In an attempt to determine risk factors associated with the ocular ischemic syndrome (OIS), the authors compared patients with severe OCAD and OIS with patients with severe OCAD without OIS. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were significantly lower in patients with severe OCAD (P < 0.01). The mean resistive indices in the central retinal and temporal short posterior ciliary arteries were higher in the group with severe OCAD (P < 0.01). Similar results were obtained in the analysis of 25 patients with asymmetric carotid stenosis. Younger age (P = 0.012), severe bilateral OCAD (P = 0.01), high-grade carotid stenosis (P = 0.013), and reversed ophthalmic artery flow (P = 0.038) were significant risk factors for OIS. CONCLUSIONS: Patients with severe OCAD show hemodynamic changes that suggest reduced retrobulbar blood flow. Patients with severe bilateral OCAD, high-grade carotid stenosis, and reversed ophthalmic artery flow may have a greater risk of developing OIS.     

Asymptomatic occlusive lesions of carotid and intracranial arteries in Japanese patients with ischemic heart disease: evaluation by brain magnetic resonance angiography

BACKGROUND AND PURPOSE: The purpose of this study was to elucidate the prevalence and degree of asymptomatic occlusive lesions in the carotid and intracranial arteries in Japanese patients with ischemic heart disease (IHD). METHODS: We performed carotid and intracranial MR angiography (MRA) on 67 patients (49 men, 18 women; age range, 40 to 78 years; mean age, 60.1 years) who had received selective coronary angiography for the clinical diagnosis of IHD. On the basis of these images, degree of stenosis in the regions of the bilateral carotid artery bifurcation and five regions of the intracranial arteries, ie, bilateral intracranial portions of the internal carotid arteries and the middle cerebral arteries and the basilar artery were estimated. RESULTS: Stenosis of more than 25% narrowing of the diameter of the target arteries was found in 15 patients (22.4%) in the extracranial carotid arteries and in 11 patients (16.4%) in the intracranial arteries. Most of the stenotic lesions were mild. The incidence of extracranial carotid stenosis and the severity of coronary atherosclerosis showed a significant correlation. The mean age of the patients with intracranial arterial lesions was statistically higher than those without intracranial lesions. CONCLUSIONS: Our data suggest that asymptomatic occlusive lesions in the carotid and intracranial arteries are fairly common in Japanese patients with IHD, although the degree of stenosis is relatively mild. Coexistence of carotid atherosclerosis should be suspected in IHD patients with severe coronary atherosclerosis, and the possibility of atherosclerosis in the intracranial arteries should be considered in aged IHD patients.     

The hemodynamics and anatomy of the circle of Willis. The technic and clinical value of selective MR angiography

This study evaluates the usefulness of MR angiography in analysing the individual collateral flow dynamics and anatomy of the circle of Willis in 56 patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar area was performed by means of presaturation up to the brain-supplying arteries at the level of the middle neck (angled presaturation slabs). Results obtained with selective and non-selective MRA in 56 consecutive patients were compared with the findings at transcranial Doppler ultrasonography and arterial angiography. Ischaemic cerebral infarctions were classified by computerized tomography and correlated with the results of collateral flow analysis: Sensitivity of selective MRA in detecting intracranial collateral flow via anterior or posterior communicating artery was 96 and 97%, respectively; sensitivity in depicting extracranial transorbital flow was lower (71%). Non-selective MRA was 100% sensitive in detecting a non-filling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Slow flow infarctions occurred more frequently in patients with transorbital and posterior-to-anterior collateral flow than in patients with collateral flow via anterior communicating artery.     

Three-dimensional ultrasound study of carotid arteries before and after endarterectomy; analysis of stenotic lesions and surgical impact on the vessel

BACKGROUND and PURPOSE: It has been proved that symptomatic patients with severe carotid stenosis benefit from endarterectomy. Currently used methods for quantitation of the severity of carotid stenosis have limitations, and the impact of endarterectomy on the operated region of carotid artery remains unknown. The purpose of this study was to examine the accuracy of a 3-D ultrasound system for quantitation of stenotic lesions and to evaluate changes in regional vessel volume and cross-sectional area after carotid endarterectomy. METHODS: We studied 14 patients with both carotid angiography and 3-D ultrasound. Of 13 patients who underwent surgery, 12 were reexamined with 3-D ultrasound after surgery. The length and volume of 20 randomly selected plaques were measured from 3-D data sets. The severity of stenosis was quantified by 3-D ultrasound using both a diameter method and an area method on cross-sectional views at the most stenotic site; the results were then compared with those from carotid angiography. The segmental vessel volume and average cross-sectional area of the operated artery both before and after endarterectomy were measured from 3-D ultrasound data. RESULTS: Good correlation was obtained between 3-D ultrasound and carotid angiography in quantitative analysis of carotid stenosis (SEE=12.4%, r=0.76, and mean difference=7.0+/-12.3% with the diameter method; SEE=10.5%, r=0.82, and mean difference=1.8+/-10.5% with the area method by 3-D ultrasound). 3-D ultrasound had excellent reproducibility and small intraobserver and interobserver variability in plaque length and volume measurements. No significant changes in segmental vessel volume and average cross-sectional area of the operated artery were observed after surgery in patients with suture closure. However, a significant increase in segmental vessel volume was obtained in patients with polyfluorethylene patches applied to the surgical opening of the artery. CONCLUSIONS: 3-D ultrasound can be used for both qualitative and quantitative analysis of plaques in the carotid artery and to detect and quantify significant carotid stenosis. Its volumetric potential has important clinical implications in serial follow-up studies for observing the progression or regression of stenotic lesions and for evaluating the outcome of interventional procedures such as endarterectomy or stent placement.     

Combined use of duplex imaging and magnetic resonance angiography for evaluation of patients with symptomatic ipsilateral high-grade carotid stenosis

PURPOSE: Advances in cerebral vascular imaging suggest that patients with critical levels of carotid artery stenosis (> 70%) who have symptoms can be identified accurately and necessary information about the intracranial and extracranial circulation obtained before surgery without conventional angiography. We have used carotid duplex imaging in combination with magnetic resonance angiography (MRA) to evaluate 20 patients with symptomatic ipsilateral high-grade carotid stenosis. METHODS: All patients underwent CT and magnetic resonance imaging brain scans, as well as MRA and conventional arteriography of the cerebral circulation. Magnetic resonance angiograms were obtained with two-dimensional phase contrast and time-of-flight techniques. Phase contrast was used for intracranial vascular imaging and for determining qualitative flow velocities and the direction of blood flow in the circle of Willis. Two-dimensional time of flight was used to assess the carotid bifurcations. RESULTS: Twenty patients with symptoms (six with strokes, 11 with transient ischemic attacks, and three with amaurosis fugax) had duplex evidence of high-grade carotid stenoses. Computed tomographic and magnetic resonance brain scans were positive for cerebral infarction in six patients with clinical strokes. Comparison of MRA with conventional angiography was 91% accurate for high-grade stenoses and occlusions (sensitivity 100% and specificity 90% for stenosis; sensitivity/specificity was 100% for complete occlusion). Comparison of duplex imaging with conventional angiography demonstrated 86% accuracy for detection of severe stenosis or occlusion (sensitivity 94% and specificity 89% for stenosis; sensitivity and specificity were 100% for complete occlusion). CONCLUSIONS: This study suggests that combined use of MRA and duplex imaging is accurate for detection and evaluation of high-grade carotid stenoses in patients with symptoms.     

Cerebral microembolism in patients with retinal ischemia

BACKGROUND AND PURPOSE: We investigated the frequency of cerebral microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. METHODS: Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. RESULTS: Microembolism was detected in 40.0% of study MCAs and 9.2% of controls (P < 0.001). In the study group, microembolic signals were detected in 61.9% of MCAs tested within a week of symptom onset and 20.8% of those tested afterward (P < 0.001). Severe (> or = 70%) carotid stenosis or occlusion was more frequent in the study group (P < 0.001). Microembolic signals were detected in 25.3% and 11.2%, respectively, of MCAs distal to carotid arteries with 70% to 100% and 0% to 69% stenosis (P = 0.013). CONCLUSIONS: In patients without cardiac embolic sources, cerebral microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.     

The use of direct intra-operative Doppler ultrasonography in carotid thromboendarteriectomy. A prospective study

Large multicenter studies have recently provided long-term results substantiating the superiority of surgical as compared to conservative treatment for symptomatic and asymptomatic extracranial internal carotid stenoses of more than 70%. These results led to an increase in the frequency of thrombo-endarteriectomies. However, indications are limited by the peri-operative complication rate. This explains the need for intra-operative quality control. The present study compares the standard method of intra-operative quality control in carotid surgery, i.e., intra-operative angiography (IOA), with direct intra-operative Doppler ultrasonography (IDU). Thirty-four patients who underwent carotid thrombo-endarteriectomy (carotid TEA) for a symptomatic (n = 15) or asymptomatic (n = 19) carotid stenosis of more than 70% were submitted to both intra-operative IOA and IDU. The sensitivity and specificity of the two techniques were compared in the light of the intra-operative findings. IDU seems to be superior to IOA in the detection of vasospasm. IOA has a higher sensitivity in demonstrating minisaccules, which, however, are not therapeutically relevant. The other findings obtained with both methods were considered to be of equal value. There were no false negative results by IDU regarding therapeutically relevant findings. We therefore consider it advisable to apply IDU in every case of carotid TEA. IOA should be performed in patients with vessel changes detected by IDU.     

An unusual parotid gland in the tent-building bat, Uroderma bilobatum: possible correlation of interspecific ultrastructural differences with differences in salivary pH and buffering capacity

PURPOSE: To determine the utility and accuracy of helical CT angiography (CTA) in the evaluation of carotid artery stenosis. METHODS: A comparison of CTA and conventional arteriogram was performed in 53 patients undergoing evaluation for carotid artery stenosis. Ninety-six carotid systems were evaluable. CTA stenosis was determined by the percent of area reduction seen on axial images through the level of greatest narrowing. MIP images were used to identify the point of maximal stenosis and to visualize overall vascular anatomy. The percent diameter stenosis was measured on conventional arteriograms using strict North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. RESULTS: Significant correlation was found between CTA and arteriography (NASCET method R=0.87, ECST method R=0.87, p < 0.001). Using NASCET >60% as an indicator for disease, CTA had a sensitivity of 87%, specificity of 90%, accuracy of 89%, negative predictive value of 88%, and positive predictive value of 89%. CTA identified plaque characteristics such as ulcerations (8), occlusion (10), fatty plaques (22), calcifications (48), and fibrosis (2). CTA underestimated 2 cases of short segment stenoses because of volume averaging, but this discrepancy was detected by duplex scan. No complications or renal dysfunction occurred with CTA; 1 patient became symptomatic during arteriography, necessitating termination of the procedure. CONCLUSION: CTA is a safe, non-invasive technique that precisely measures carotid artery area reduction and highly correlates to conventional arteriography. With this new technology, the current standards for carotid artery imaging may need to be reevaluated, and the precise role for helical CTA more clearly defined.     

Restenosis and remodeling after percutaneous transluminal carotid angioplasty

INTRODUCTION: The characteristics of restenosis and remodeling after carotid percutaneous transluminal angioplasty (PTA) were badly known. OBJECTIVE: To describe these characteristics in our series of carotid PTA. PATIENTS AND METHODS: A total of 78 cases of PTA for symptomatic > 70% atherosclerotic stenosis of the extracranial internal carotid artery, were selected from our series of PTA if follow-up was > 12 months. All of them were followed with extracranial continuous-wave Doppler. RESULTS: Restenosis of any degree was found in 17 cases (21.79%) and always asymptomatic. A restenosis > or = 70% was found in 5 cases (6.4%). Restenosis was mainly found in cases without residual stenosis nor dissection after PTA (p = 0.002). Restenosis was found in 16 cases (94.11%) in the first 6-months, with no progression thereafter. Remodeling of residual stenosis was frequent (17 cases; 53.11%) and found mainly during the first month after PTA. Its incidence was highest in patients with dissection treated with heparin. In cases with restenosis, remodeling was infrequent, incomplete and occurred after 18-24 months. CONCLUSIONS: 1. Significant restenosis after PTA due to myointimal proliferation, was infrequent. All cases were asymptomatic, under antiplatelet treatment. A new interventional procedure might not be necessary. 2. Complete remodeling was frequently found after 1-month control, mainly in arteries with some residual stenosis and dissection after PTA.     

Relation among stenosis severity, myocardial blood flow, and flow reserve in patients with coronary artery disease

BACKGROUND: Coronary arteriography is considered the "gold standard" for evaluating the severity of a coronary stenosis. Because the resistance to blood flow through a stenotic lesion depends on a number of lesion characteristics, the physiological significance of coronary lesions of intermediate severity is often difficult to determine from angiography alone. This study of patients with coronary artery disease seeks to determine the relation between myocardial blood flow and flow reserve measured by positron emission tomography (PET) and the percent area stenosis on quantitative coronary arteriography. METHODS AND RESULTS: We studied 28 subjects: 18 patients with coronary artery disease (66 +/- 8 years) and 10 age-matched healthy volunteers (64 +/- 13 years) with dynamic N-13 ammonia PET imaging at rest and after dipyridamole (0.56 mg/kg). The percent cross-sectional area stenosis was quantified on the coronary arteriograms as described by Brown et al. In the 18 patients, a total of 41 non-infarct-related coronary vessels were analyzed. Myocardial blood flows in normal regions of patients with coronary artery disease were not different than those in healthy volunteers, both at rest and after dipyridamole. As a result, the myocardial flow reserve was also similar in both groups (2.4 +/- 0.4 versus 2.6 +/- 0.7, respectively; P = NS). Quantitative PET estimates of hyperemic blood flow (r = .81, P < .00001), flow reserve (r = .78, P < .00001), and an index of the "minimal coronary resistance" (r = .78, P < .00001) were inversely and nonlinearly correlated with the percent area stenosis on angiography. Of note, PET estimates of myocardial flow reserve successfully differentiated coronary lesions of intermediate severity (50% to 70% and 70% to 90%; 2.4 +/- 0.4 versus 1.8 +/- 0.5, respectively; P = .04). CONCLUSIONS: In patients with coronary artery disease, non-invasive measurements of myocardial blood flow and flow reserve by PET are inversely and nonlinearly related to stenosis severity as defined by quantitative angiography. Importantly, coronary lesions of intermediate severity have a differential flow reserve that decreases as stenosis increases that can be detected noninvasively by PET, thus allowing better definition of the functional importance of known coronary stenosis.     

Does arterial recanalization improve outcome in carotid territory stroke?

BACKGROUND AND PURPOSE: We sought to determine whether early (< 8 hours) or delayed (8 to 24 hours) recanalization after stroke may be an independent variable in the improvement of clinical outcome in patients with occlusion of the middle cerebral artery. METHODS: We prospectively studied 77 patients by combined Scandinavian Stroke Scale score at admission, repeated computed tomography and angiography before and after thrombolytic treatment at < 8 hours after stroke onset, and transcranial Doppler ultrasound 24 hours later. We tested an association between clinical and neuroradiological baseline characteristics, recanalization, and outcome as assessed by the modified Rankin Scale 4 weeks after stroke and determined the effect of recanalization on mortality and good outcome (Rankin Scale grades 0 to 3) by multiple logistic regression analyses. RESULTS: Recanalization rates at 8 and 24 hours after stroke correlated with sites of occlusion (middle cerebral artery branch, 73% and 73%, trunk, 27% and 38%, respectively; intracranial internal carotid artery bifurcation, 14% and 14%; P = .002), collaterals (good, 43% and 51%, respectively; scarce, 17% and 19%, respectively; P = .01), and Scandinavian Stroke Scale score at admission (P = .002). Six of 6 patients with delayed recanalization had good outcomes. Recanalization at < 8 hours after symptom onset had no independent predictive value for good outcome (P = .69). Recanalization at 24 hours increased the proportion of good outcomes from 23% to 75% in a subgroup of patients. Recanalization did not independently affect mortality (P > .15). CONCLUSIONS: Even if delayed, arterial recanalization may improve clinical outcome in a subgroup of patients with middle cerebral artery occlusion.