Familial adhesive arachnoiditis associated with syringomyelia.

Adhesive arachnoiditis is a rare condition, often complicated by syringomyelia. This pathologic entity is usually associated with prior spinal surgery, spinal inflammation or infection, and hemorrhage. The usual symptoms of arachnoiditis are pain, paresthesia, and weakness of the low extremities due to the nerve entrapment. A few cases have had no obvious etiology. Previous studies have reported one family with multiple cases of adhesive arachnoiditis. We report a second family of Belgian origin with multiple cases of arachnoiditis and secondary syringomyelia in the affected individuals.

Platelet activation during carotid endarterectomy and the antiplatelet effect of Dextran 40.

OBJECTIVE: To determine changes in platelet activation during carotid endarterectomy (CEA) and the antiplatelet effect of Dextran 40. METHODS: Prospective study in 40 patients undergoing CEA. Platelet activity was measured by whole blood flow cytometry and platelet aggregometry during CEA. The expression of P-selectin and the PAC-1 antigen were used as markers of platelet activation and aggregation. Patients received aspirin (75-300 mg) preoperatively and 5,000 units unfractionated heparin during surgery. High intensity transient signals (HITS) in the ipsilateral middle cerebral artery were monitored using transcranial Doppler (TCD) perioperatively. RESULTS: P-selectin expression increased after carotid clamping (P < 0.01) and clamp release (P < 0.05). There was higher expression of PAC-1 after carotid clamping (p < 0.05). Spontaneous and ADP-induced platelet aggregation increased after carotid clamping (P< 0.01) and release (P < 0.01). TCD monitoring showed an increased HITS count from preoperative levels, after clamp release (P < 0.01) and during recovery (P < 0.01). After the operation, patients with more than 50 HITS per 30 min were started on an infusion of dextran 40 (n = 6). P-selectin expression decreased 24 h after dextran 40 (P < 0.01). CONCLUSION: Significant platelet activation and aggregation occurs during CEA despite the current use of antiplatelet treatment. Dextran 40 had an antiplatelet effect after CEA providing further evidence that it may contribute to reducing thromboembolic complications.

Brain CT infarction in patients with carotid atheroma. Does it predict a future event?

BACKGROUND: The aim of the present study was to investigate the predictive value for subsequent stroke of different patterns of brain CT infarction in patients with carotid atheroma. METHODS: Prospective study on 138 patients, with 138 carotid plaques, having, on presentation, a greater than 50 percent stenosis on duplex scanning and associated with an ipsilateral (to the plaque) amaurosis fugax (AF), hemispheric transient ischaemic attack (HTIA) or which were asymptomatic. This carotid artery defined the side of interest. All patients had a brain CT scan on presentation and subsequently were followed for a period of 1-5 years (mean 3.14). The baseline CT neurovascular findings on the side of interest were classified as pattern A (discrete subcortical and cortical infarctions), pattern B (haemodynamic infarctions, widespread white matter lesions, basal ganglia infarctions and lacunae) and normal CT. RESULTS: On follow-up, 5/27 (18.5 percent) of patients with pattern A, 4/38 (10.5 percent) with pattern B and 3/73 (4.1 percent) with normal CT appearance developed stroke in the hemisphere of interest (Cox regression: p=0.02). CONCLUSIONS: Pattern A confers an unfavourable prognosis in patients with carotid atheroma who are either asymptomatic or presented with amaurosis fugax or hemispheric transient ischaemic attacks.

Significance of sonographic tissue and surface characteristics of carotid plaques.

BACKGROUND AND PURPOSE: Our hypothesis was that symptomatic and asymptomatic carotid plaques are different. The aim of this study was to identify the sonographic tissue and surface characteristics of plaques and their degree of stenosis that corresponded to these two clinical presentations. METHODS: We studied 81 symptomatic and 111 asymptomatic plaques (150 patients) having 50% to 99% stenosis on duplex scanning. These plaques were imaged on duplex and captured in a computer. We evaluated the gray-scale median (GSM) to distinguish hypoechoic (low GSM) from hyperechoic (high GSM) plaques, and the bending energy (BE), to distinguish plaques with irregular (high BE) versus smooth (low BE) surfaces. RESULTS: The symptomatic group corresponded to hypoechoic (median GSM, 4) and severely stenosed (median stenosis, 85%) plaques, whereas the asymptomatic group corresponded to hyperechoic (median GSM, 35) and moderately stenosed (median stenosis, 70%) plaques (P <.05 for both variables). The BE failed to separate the two groups; the mean BEs were 1.63 and 1.68 for the symptomatic and asymptomatic groups, respectively (P =.38). CONCLUSION: Our results suggest that echogenic characteristics and the degree of stenosis are the strongest predictors of carotid plaque behavior. The sonographic surface characteristics failed to qualify as an index of plaque instability.

Determinants of carotid plaque instability: echoicity versus heterogeneity.

OBJECTIVE: to identify the echoicity and heterogeneity of carotid plaques associated with ipsilateral symptomatic and asymptomatic neurovascular presentations. DESIGN: cross-sectional study. MATERIALS: a total of 113 patients, with 127 symptomatic and asymptomatic plaques, were studied. METHODS: the duplex images of the plaques were analysed echoically in a computer by means of Grey Scale Median (GSM) [hypoechoic (low GSM), hyperechoic (high GSM)]. The presence or absence of at least two plaque regions within the plaque area being echoically uniform (no variation of echoicity), occupying each at least 10% of the plaque area and having GSM difference greater than the plaque GSM was evaluated to distinguish the heterogeneous (presence of this pattern) from the homogeneous (absence of this pattern) plaques. RESULTS: the symptomatic status was associated with plaques of low median GSM (10.5) and 88% prevalence of the homogeneous pattern as contrasted with the asymptomatic status that was associated with high median GSM (28) and 65% prevalence of the homogeneous pattern [(p=0.001 (GSM), p=0.003 (heterogeneity)]. CONCLUSIONS: symptomatic plaques were associated with hypoechoic and predominant homogeneous echo-pattern whereas the asymptomatic ones were associated with hyperechoic and less predominant homogeneous pattern.

Carotid plaque echogenicity and types of silent CT-brain infarcts. Is there an association in patients with asymptomatic carotid stenosis?

BACKGROUND: The aim of this study was to identify the differences in echogenicity and the degree of stenosis of asymptomatic carotid plaques associated with different types of ipsilateral silent CT-brain infarcts. METHODS: Some 273 asymptomatic carotid plaques (218 patients) causing 50 to 99% stenosis were studied with high-resolution ultrasound. B-mode images were digitised and normalised by assigning certain grey values to blood and adventitia. The grey scale median (GSM) of the plaque in the normalised image was used to quantify echogenicity. Every patient had a CT-brain scan which an independent neuroradiologist read. The presence of 1) non-lacunar and 2) lacunar silent CT-brain infarcts ipsilateral to the carotid plaque was noted. RESULTS: The mean GSM of plaques associated with non-lacunar silent CT-brain infarcts was 19.6, of plaques associated with lacunar infarcts was 35.5 and of those associated with no infarcts was 32 (p=0.008, ANOVA). The mean degree of stenosis was 79%, 72% and 73% respectively (p = 0.1, ANOVA). Plaque echogenicity (p = 0.007) and not the degree of stenosis (p = 0.07) predicted the presence of non-lacunar silent CT-brain infarcts (logistic regression). CONCLUSIONS: Carotid bifurcation plaques, which are associated with non-lacunar silent CT-brain infarcts, are significantly more hypoechoic than those associated with lacunar or no infarcts. Plaques associated with lacunar silent infarcts and no infarcts have the same echogenicity and degree of stenosis. These findings suggest an embologenic mechanism of non-lacunar silent CT-brain infarcts that may have prognostic implications in patients with asymptomatic carotid stenosis. Prospective studies of asymptomatic carotid stenosis should assess the significance of 1) plaque echogenicity and 2) the presence of different types of silent CT-brain infarcts and atheroembolic stroke.

The genesis of atherosclerosis and risk factors: a review.

Atherosclerosis constitutes the most common medical and surgical problem. This can be manifested clinically as stroke, coronary artery disease, or peripheral vascular disease. In the present review the microscopic appearance of the normal arterial wall, the definition of atherosclerosis and the five theories of atherogenesis are described. These are: the lipid theory, the hemodynamic theory, the fibrin incrustation theory, the nonspecific mesenchymal hypothesis and the response to injury hypothesis. Based on the above theories the sequence of events in atherogenesis is analyzed. The classification of the atherosclerotic lesions according to Stary (types I-VI) and their characteristics appear in a table. The epidemiology and the role of the following risk factors are presented in detail: age, sex, lipid abnormalities, cigarette smoking, hypertension, diabetes mellitus, physical inactivity, alcohol consumption, obesity, and hemostatic factors. In addition, less common genetically determined associations like homocystinuria, Tangier disease, Hutchinson-Gilford syndrome (progeria), Werner's syndrome, radiation induced atherosclerosis and the implications of Chlamydia pneumoniae on the arterial wall are discussed.

Patterns of brain computed tomography infarction and carotid plaque echogenicity.

PURPOSE: It was suggested that in the absence of cardioembolism the discrete subcortical and cortical infarctions on brain computed tomography (CT) are most likely associated with carotid atheroma, whereas the hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions are most likely associated with other pathologic conditions. The aim of this study was to determine the ultrasonic characteristics of carotid plaques and the degree of stenosis that were associated with the different brain CT infarction patterns and normal CT (pattern A, discrete subcortical and cortical infarctions; pattern B, hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions). METHODS: Four hundred nineteen carotid plaques (315 patients), producing 50% to 99% stenosis on duplex scanning, were studied. These plaques were imaged on duplex scanning, captured, digitized, and normalized (standardized) in a computer. Subsequently, their gray scale median (GSM) was evaluated to distinguish quantitatively the hypoechoic (low GSM) from the hyperechoic (high GSM) plaques. The brain CT infarction patterns of A, B, or normal CT on the ipsilateral hemisphere were noted. RESULTS: The pattern A brain CT infarction was associated with carotid plaques having median GSM of 11 and median degree of stenosis of 80%, as contrasted with pattern B (median GSM, 28.5; median degree of stenosis, 75%) or normal CT (median GSM, 22; median degree of stenosis, 75%) (Kruskal-Wallis test, P <.001 for the GSM and P =.002 for the degree of stenosis). In the logistic regression analysis only the GSM and not the degree of stenosis distinguished the plaques associated with the three CT patterns. CONCLUSIONS: The pattern A brain CT infarction was associated with hypoechoic plaques suggesting an involvement of extracranial carotid artery embolization, whereas the pattern B was associated with hyperechoic plaques suggesting an involvement of other mechanisms (hemodynamic, intracranial small and large vessel disease).

Types of neurovascular symptoms and carotid plaque ultrasonic textural characteristics.

The aim of this study was to identify the echo morphology and stenosis of carotid plaques that corresponded to ipsilateral asymptomatic status, amaurosis fugax, hemispheric transient ischemic attack, and stroke. One hundred ninety-two plaques (150 patients), producing stenosis in the range of 50% to 99% and associated with various neurovascular manifestations, were studied. These plaques were imaged on duplex scans, and a series of textural features was produced in a computer to distinguish quantitatively their various echo patterns. Amaurosis fugax corresponded to dark, severely stenosed atheromas (90%); hemispheric transient ischemic attack and stroke corresponded to plaques with intermediate echoic characteristics and intermediate stenosis (80%); and asymptomatic status corresponded to bright, moderately stenosed plaques (70%; P < .05). The significance of these findings is discussed.

Correlates of embolic events detected by means of transcranial Doppler in patients with carotid atheroma.

PURPOSE: This study identified in patients with carotid plaques the associations of emboli detected by means of transcranial Doppler (TCD) with cerebrovascular symptoms, brain computed tomography (CT) infarction patterns, and the attributes of plaques (echodensity, degree of stenosis). METHODS: Eighty carotid plaques (in 59 patients), producing 50% to 99% stenosis, were imaged on duplex scanning and analyzed echomorphologically in a computer with the gray scale median (GSM). The GSM facilitated the quantitative distinction of dark (low GSM) from bright (high GSM) plaques. Stenosis was assessed with duplex scanning. Emboli were counted on TCD in the ipsilateral middle cerebral artery for half an hour. The brain CT infarction patterns (pattern A: discrete subcortical and cortical; pattern B: hemodynamic, diffuse white matter lesions, basal ganglia infarctions, lacunes) and normal CT and cerebrovascular symptoms on the ipsilateral hemisphere were noted. RESULTS: Emboli were more frequent in symptomatic (median count, 3) than asymptomatic (median count, 0) hemispheres (Mann-Whitney U test, P =.031) and in hemispheres with pattern A infarction (median count, 3.5) than in hemispheres with pattern B infarction or normal CT (median count, 0; Kruskal-Wallis test, P =.047). The increased embolic count was associated with decreased GSM (Spearman correlation, P =.045, r = -0.22), but not with high degrees of stenosis (Spearman correlation, P =.44, r = 0.086). CONCLUSION: Emboli were more frequent in symptomatic than asymptomatic hemispheres and in CT pattern A harboring hemispheres than in CT pattern B or normal hemispheres. They were more frequent in the presence of low-plaque echodensity, but not in the presence of a high degree of stenosis. These data support the embolic nature of cerebrovascular symptomatology and CT pattern A infarctions.

The significance of the cerebral collateral capacity in patients with carotid atheroma.

OBJECTIVES: to identify the echodensity, stenosis of carotid plaques and cerebral collateral capacity that were associated with various ipsilateral presentations (retinal, cerebrovascular, asymptomatic). DESIGN: cross-sectional study. MATERIALS: forty-four patients, with 44 plaques associated with various presentations, were studied. METHODS: the duplex images of the plaques were analysed echomorphologically in a computer by means of Grey Scale Median (GSM) [hypoechoic (low GSM), hyperechoic (high GSM)]. The percentage (%) reduction of the mean velocity in the middle cerebral artery (PRMCA) on transcranial Doppler, during clamping in carotid endarterectomy, was evaluated to distinguish the competent cerebral collateral supply (low PRMCA) from the non-competent one (high PRMCA). RESULTS: the retinal symptoms were associated with plaques of low median GSM (0), severe median stenosis (90%) and low median PRMCA (0.31) as contrasted with the cerebrovascular symptoms (17, 84%, 0.47, respectively) and asymptomatic status (32, 83%, 0.4, respectively) [(p =0.038 (GSM), p =0.67 (stenosis), p=0.15 (PRMCA)]. The retinal and the cerebrovascular symptoms were distinct in terms of PRMCA (p=0.045). CONCLUSIONS: the retinal symptoms were produced by hypoechoic and possibly embologenic plaques, whereas the cerebrovascular ones possibly by the combination of carotid embolism and a non-competent cerebral collateral circulation. Asymptomatic status was associated with the absence of any relevant mechanism.

Echomorphologic and histopathologic characteristics of unstable carotid plaques.

BACKGROUND AND PURPOSE: Our hypothesis was that the carotid plaques associated with retinal and cerebrovascular symptomatology and asymptomatic presentation may be differ from each other. The aim of this study was to identify the sonographic and histopathologic characteristics of plaques that corresponded to these three clinical manifestations. METHODS: The echo process involved duplex preoperative imaging of 71 plaques (67 patients, 21 plaques were associated with retinal, 25 with cerebrovascular symptoms, and 25 were asymptomatic), which was performed in a longitudinal fashion. Appropriate frames were captured and digitized via S-video signal in a computer and digitized sonograms were normalized by two echo-anatomic reference points: the gray scale median (GSM) of the blood and that of the adventitia. The GSM of the plaques was evaluated to distinguish dark (low-GSM) from bright (high-GSM) plaques. Subsequent to endarterectomy, the plaques were sectioned transversely, and a slice at the level of the largest plaque area was examined for the relative size of necrotic core and presence of calcification and hemorrhage. RESULTS: Retinal symptomatology was associated with a hypoechoic plaque appearance (median GSM: 0), asymptomatic status with a hyperechoic plaque appearance (median GSM: 34), and cerebrovascular symptomatology with an intermediate plaque appearance (median GSM: 16) (P = .001). The histopathologic characteristics did not disclose differences between the three clinical groups. The hypoechoic plaque appearance was associated only with the presence of hemorrhage (median GSM for the hemorrhagic plaques, 6, and for the non-hemorrhagic ones, 20 [P = .04]). The relative necrotic core size and the presence of calcification did not show any echomorphologic predilection. CONCLUSION: Our results showed that distinct echomorphologic characteristics of plaques were associated with retinal and cerebrovascular symptomatology and asymptomatic status. Histopathologically, only the presence of hemorrhage proved to have an echomorphologic predilection.

Stroke: epidemiology, clinical picture, and risk factors--Part I of III.

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part II the pathogenesis, investigations, and prognosis will be presented, while part III will consist of the management and rehabilitation). In the current part (I) the definitions of the clinical picture are presented. These include: amaurosis fugax, vertebrobasilar transient ischemic attack, and stroke (with good recovery, in evolution and complete). The role of the following risk factors is discussed in detail: age, gender, ethnicity, heredity, hypertension, cigarette smoking, hyperlipidemia, diabetes mellitus, obesity, fibrinogen and clotting factors, oral contraceptives, erythrocytosis and hematocrit level, prior cerebrovascular and other diseases, physical inactivity, diet and alcohol consumption, illicit drug use, and genetic predisposition. In particular, regarding the carotid arteries, the following characteristics are analyzed: atheroma, carotid plaque echomorphology, carotid stenosis, presence of ulcer, local variations in surface deformability, pathological characteristics, and dissection. Finally the significance of the cerebral collateral circulation and the conditions predisposing to cardioembolism and to cerebral hemorrhage are presented.

Stroke: pathogenesis, investigations, and prognosis--Part II of III.

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part I the epidemiology, clinical picture, and risk factors were discussed, while part III will consist of the management and rehabilitation). In the present part (II) the pathogenetic and pathophysiologic aspects of stroke are described. Regarding the investigations apart from the history and clinical examination and general investigations, the following specialized investigations and their role are discussed in detail: Computed tomography (CT), magnetic resonance imaging (MRI), xenon-blood-flow, positron emission tomography (PET), cerebral angiography, magnetic resonance angiography (MRA), ultrasonography, transcranial Doppler (TCD), echocardiography, Holter monitoring, and biopsies. In addition, taking into account the information from the above-cited modalities a prognosis for the final outcome is presented.

Patterns of cerebrovascular symptomatology associated with carotid atheroma.

The aim of this study was to identify ultrasonic tissue characteristics and stenosis of carotid plaques that correspond to amaurosis fugax, hemispheric transient ischaemic attack, and stroke. At total of 146 symptomatic carotid plaques (136 patients) associated with amaurosis fugax, hemispheric transient ischaemic attack, stroke, and having 50-99% stenosis on duplex, were studied. These plaques were imaged on duplex, captured in a computer and their grey scale median was evaluated to distinguish the dark (low grey scale median) from the bright (high grey scale median) plaques. Stenosis was assessed on duplex. The amaurosis fugax group corresponded to carotid plaques with low grey scale median and severe stenosis, as contrasted with the other two groups (hemispheric transient ischaemic attack and stroke) (P < 0.05). These results suggested that amaurosis fugax was dependent only on the instability of carotid plaques, whereas hemispheric transient ischaemic attack and stroke were both dependent on carotid plaques and other pathogenetic factors.

Reproducibility of computer-quantified carotid plaque echogenicity: can we overcome the subjectivity?

BACKGROUND AND PURPOSE: We sought to assess the reproducibility, interobserver variability, and application to clinical studies of a new method for the quantitative assessment of carotid plaque echogenicity. METHODS: Carotid plaques were scanned with the use of ultrasound, and their images were stored in a computer. They were normalized by assigning certain gray values to blood and adventitia, and the gray scale median (GSM) was used to quantify their echogenicity. The variability between storage media, between degrees of magnification, and between probes was assessed. The method was applied to 232 asymptomatic carotid plaques causing 60% to 99% stenosis in relation to the presence of ipsilateral CT-demonstrated brain infarcts. In all parts of the study the plaque GSM was measured before and after normalization to evaluate its effect. Interobserver agreement for the scanning process was assessed. RESULTS: The GSM mean difference before and after normalization for variability studies of storage media, degrees of magnification, and probes was -14.5 and -0.12, 2.24 and 1.68, and -8.3 and -0.7, respectively. The median GSM of plaques associated with ipsilateral nonlacunar silent CT-demonstrated brain infarcts was 14, and that of plaques that were not so associated was 30 (P:=0.003). The interobserver GSM difference was -0.05 (95% CI, -1.7 to 1.6). CONCLUSIONS: Our method decreases the variability between storage media and between probes but not the variability between degrees of magnification. It separates echomorphologically the carotid plaques associated with silent nonlacunar CT-demonstrated brain infarcts from plaques that are not so associated.

Comparability of the ultrasonic tissue characteristics of carotid plaques.

Hypoechoic carotid atherosclerotic plaques on ultrasonographic examination were found to be associated with cerebrovascular events. This underlines the need for an accurate evaluation of their echotexture characteristics. The objective of this study was to further validate a proposed method of normalization aiming to facilitate the comparability of these characteristics. The sonographic examination involved imaging of carotid plaques using duplex technique and capturing, digitization, and normalization in a computer in a standard way. In the first part, the interobserver and interscanner variability and the gain-level variability within the ultrasound unit were examined, before and after normalization, in terms of plaque echotexture. The second part investigated the effect of normalization on the echotexture of 419 symptomatic and asymptomatic plaques. Our results indicated that the normalization reduced the interscanner variability and the gain-level variability. The interobserver variability was excellent. In addition, this process further distinguished the echotexture characteristics of symptomatic and asymptomatic carotid plaques, which encourages the use of this method in natural history studies in persons with asymptomatic carotid atherosclerotic disease, aiming to identify those at higher risk for stroke. These patients might benefit from a carotid endarterectomy.

Hemispheric symptoms and carotid plaque echomorphology.

PURPOSE: In patients with carotid bifurcation disease, the risk of stroke mainly depends on the severity of the stenosis, the presenting hemispheric symptom, and, as recently suggested, on plaque echodensity. We tested the hypothesis that asymptomatic carotid plaques and plaques of patients who present with different hemispheric symptoms are related to different plaque structure in terms of echodensity and the degree of stenosis. METHODS: Two hundred sixty-four patients with 295 carotid bifurcation plaques (146 symptomatic, 149 asymptomatic) causing more than 50% stenosis were examined with duplex scanning. Thirty-six plaques were associated with amaurosis fugax (AF), 68 plaques were associated with transient ischemic attacks (TIAs), and 42 plaques were associated with stroke. B-mode images were digitized and normalized using linear scaling and two reference points, blood and adventitia. The gray scale median (GSM) of blood was set to 0, and the GSM of the adventitia was set to 190 (gray scale range, black = 0; white = 255). The GSM of the plaque in the normalized image was used as the objective measurement of echodensity. RESULTS: The mean GSM and the mean degree of stenosis, with 95% confidence intervals, for plaques associated with hemispheric symptoms were 13.3 (10.6 to 16) and 80.5 (78.3 to 82.7), respectively; and for asymptomatic plaques, the mean GSM and the mean degree of stenosis were 30.5 (26.2 to 34.7) and 72. 2 (69.8 to 74.5), respectively. Furthermore, in plaques related to AF, the mean GSM and the mean degree of stenosis were 7.4 (1.9 to 12. 9) and 85.6 (82 to 89.2), respectively; in those related to TIA, the mean GSM and the mean degree of stenosis were 14.9 (11.2 to 18.6) and 79.3 (76.1 to 82.4), respectively; and in those related to stroke, the mean GSM and the mean degree of stenosis were 15.8 (10.2 to 21.3) and 78.1 (73.4 to 82.8), respectively. CONCLUSION: Plaques associated with hemispheric symptoms are more hypoechoic and more stenotic than those associated with no symptoms. Plaques associated with AF are more hypoechoic and more stenotic than those associated with TIA or stroke or those without symptoms. Plaques causing TIA and stroke have the same echodensity and the same degree of stenosis. These findings confirm previous suggestions that hypoechoic plaques are more likely to be symptomatic than hyperechoic ones. They support the hypothesis that the pathophysiologic mechanism for AF is different from that for TIA and stroke.

Stroke: management and rehabilitation. Part III of III.

The aim of this review is to present the current knowledge regarding stroke. It appears in three parts (in part I the epidemiology, clinical picture, and risk factors were discussed, while part II dealt with the pathogenesis, investigations, and prognosis). In this part (III) the management is presented. In an acute stroke the role of the following is discussed in detail: Thrombolysis, anticoagulant agents, and prophylactic neuroprotection with pharmacologic agents. For the prevention of stroke apart from the risk factors, which were presented in part I, the current knowledge with pharmacologic agents is discussed. Also the role of carotid endarterectomy, extracranial-intracranial bypass surgery, carotid artery angioplasty and stenting, and the treatment of cerebral hemorrhage are described. Finally the means and possibilities of rehabilitation are discussed.

New information on the value of plaque characterisation--relation to symptoms.

This paper reviews the literature on the significance of carotid plaque echomorphology and degree of stenosis in relation to the different types of cerebrovascular symptomatology (amaurosis fugax, hemispheric transient ischaemic attacks, stroke) and the asymptomatic status. It provides evidence that amaurosis fugax is associated with hypoechoic and severely stenosed plaques, the hemispheric transient ischaemic attacks and stroke are associated with plaques of intermediate echodensity and stenosis while the asymptomatic status is associated with hyperechoic and moderately stenosed plaque. It lends support to the notion that plaque hypoechoicity is associated with embologenicity. It supports the view that the severe carotid stenosis facilitates the opening of the cerebral collateral circulation and that amaurosis fugax is associated with an "opened" cerebral collateral supply as contrasted to the cerebrovascular symptomatology. It proposes the inclusion of the cerebral collateral circulation as a stroke risk factor along with the plaque echomorphology and the degree of stenosis in the natural history studies of asymptomatic individuals with carotid bifurcation plaques.