Carotid arteries: evaluation with low-field-strength MR angiography

Magnetic resonance (MR) angiography of neck vessels was performed with a 0.2-T permanent magnet by using a two-dimensional, time-of-flight technique. Thirty-one patients were included in the study. The imaging parameters used included a repetition time of 60 msec, an echo time of 10 msec, a 90 degrees flip angle, and a 192 x 256 matrix; 40-50 sequential two-dimensional sections were acquired through the neck. Stenosis was graded on a scale of 1-5. Correlation of digital and MR angiography was made in the clinically nonrelevant cases (stenoses of grades 1 and 2), with overestimation to grade 3 in six cases. Two grade 3 stenoses were overestimated as grade 4. Severe stenoses were correctly characterized in all but one case, which was underestimated because of a segmental short extension of the stenotic lesion. Obstructions were found in two cases. Areas with a lack of signal were observed in four patients with severe stenosis and in two with tortuous arteries. Correct diagnosis, however, was achieved with analysis of the maximum intensity projection animation display. Low-field-strength MR angiography has the same clinical value as that performed with high field strengths.

Correlation of ophthalmic findings with carotid artery stenosis

Patients presenting with symptoms suggestive of amaurosis fugax, or with findings of Hollenhorst plaques on fundoscopy are frequently referred for duplex evaluation to detect possible carotid artery disease. To better determine the reliability of monocular visual loss and the presence of Hollenhorst plaques for predicting the presence or significance of carotid artery stenosis, we prospectively studied 66 patients with these ocular signs and symptoms. After evaluation, the patients were categorized as follows: 34 of 66 (52%) patients had amaurosis fugax, 23 (35%) had asymptomatic Hollenhorst plaques, 7 (11%) had retinal artery occlusion, and 2 (3%) had venous stasis retinopathy. All patients were evaluated ophthalmologically, with carotid duplex scanning and spectral analysis. A stenosis of greater than 60% was regarded as significant. The presence of risk factors including hypertension, diabetes, a history of CVA or TIA's, tobacco use and hyperlipidemia was recorded. There were no statistically significant differences (p greater than 0.05) in the incidence of atherosclerotic risk factors between the four groups. Patients with amaurosis fugax were more likely to have a significant carotid artery stenosis than those with asymptomatic Hollenhorst plaques or retinal artery occlusion (53% vs 9% vs 0% respectively) (p less than 0.006). We conclude that routine carotid duplex scanning is indicated in all patients with amaurosis fugax in view of the frequent association with significant carotid stenosis (53%). However, the presence of Hollenhorst plaques in the absence of visual symptoms appears not to have a significant association with carotid disease and may not necessarily require routine screening unless other risk factors for carotid stenosis are present.(ABSTRACT TRUNCATED AT 250 WORDS)

[Electroencephalogram dynamics in Matas' compression test as a criterion of the efficacy of reconstructive operations on the vessels of the carotid basin]

EEG recording with Matas' compression test makes it possible to specify the immediate contribution of the carotid artery to the activity of the cerebral cortex neurons. This supplements the quantitative study of the linear and volume blood flow in the carotid bed. The positive result in compression of the carotid artery is characterized by a stereotype reconstruction of the brain biopotentials on the EEG reflecting the beginning of nerve cell hypoxia. Change of the EEG response in Matas' test after reconstructive operations--endarterectomy of the carotid artery and formation of extra-intracranial microvascular anastomosis--points to the contribution of the carotid artery to the general cerebral blood flow under the new conditions. It is noted that the significance of the newly formed vascular bed in the cerebral blood supply increases gradually and individually in different patients. This is evidently determined by the differences in the severity and spread of atherosclerosis of the cerebral vessels, the arterial pressure level in various vascular beds of the brain, the degree of development of anastomoses and synangioses between the branches of the internal and external carotid arteries, etc.

Takayasu's arteritis: anatomic change before and after steroid therapy evaluated by angiography and echo-Doppler color-flow

A 36-year-old Italian woman with active Takayasu's disease presented a bilateral occlusions of subclavian artery and stenosis of bilateral common carotid arteries: the maximal diameter stenosis, measured with echo-Doppler color-flow (EDCF) in the longitudinal section was of 43.5 +/- 2.4% on the right and 61 +/- 1.4% on the left. Prednisolone was administered for 30 months at doses from 25 to 6 mg daily (12.5 mg every two days). During steroid therapy we could monitor by EDCF the anatomic change of the involved vessel and a final decrease in carotid wall thickening of 19.8% on the left and 14.0% on the right side. This work demonstrates for the first time that duplex sonography may be an useful tool to asses possible anatomic changes in the carotid lesions of Takayasu's arteritis in response to steroid therapy.

[Role of loco-regional anesthesia in the surgical treatment of atheromatous lesions of the carotid bifurcation]

The Authors report a case of carotid bifurcation endarterectomy under loco-regional anesthesia. Despite a stump pressure of 44 mmHg, considered by the most of the Authors, the borderline value for carotid endarterectomy without shunt, the patient had a cerebral ischemic attack after 30 seconds of carotid clamping. So, the local anesthesia represents a valid alternative in order to detect an intolerance to clamping and underlines the importance of cerebral protection in this kind of surgical approach.

Outcome of progression from carotid stenosis to occlusion

The incidence of symptoms at the moment the internal carotid artery (ICA) occludes was assessed in 33 patients. Duplex scanning was performed to determine the progression from stenosis to ICA occlusion. There were 24 patients with a primary stenosis and nine with a restenosis after a carotid endarterectomy. In 18% (6/33) the occlusion was accompanied by a stroke. A transient ischaemic attack (TIA) was seen in 12% (4/33) of patients and 70% (23/33) remained asymptomatic. There was no difference in stroke rate between patients with primary stenosis (4/24:17%) and those with restenosis (2/9:22%). The mean follow-up was 3.2 years and the mean elapse time to occlusion in patients with a stroke was 20 months, with a TIA, 32 months, and in asymptomatic patients, 44 months. It was also shown that a stenosis of greater than 80% diameter reduction had a faster progression (mean 1 year) than a less than 80% stenosis (mean 3.5 years) (p = 0.04). Patients with a stenosis greater than 80% tended to have a higher incidence (40%:2/5) of stroke at the time of occlusion than patients with a stenosis less than 80% (14%:2/28). The results show that an occlusion of the ICA is accompanied by a stroke in 18% of the cases and that patients with a rapid progression and/or greater than 80% stenosis are at high risk. From this point of view a carotid endarterectomy should be considered in order to prevent an occlusion of the ICA and a high risk of stroke.

Internal carotid artery occlusion associated with Mycoplasma pneumoniae infection

A 12-year-old girl with serologically-proved Mycoplasma pneumoniae infection developed right-sided hemiparalysis 10 days after the onset of the disease. Cerebral infarction was documented by cranial computed tomography; cerebral angiography revealed left carotid artery occlusion. Cerebrospinal fluid examination was normal. Cerebral infarction is a rare central nervous system complication of M. pneumoniae infection; however, occlusion of the internal carotid artery near the bifurcation has never been demonstrated; therefore, this patient with central nervous system complication of M. pneumoniae infection is unique.

[Vasotonometry in the episcleral arteries in the diagnosis of stenotic lesions of the extracranial sections of the carotid arteries]

The object of the work was evaluation of the method of vasotonometry (VTM) in the episcleral arteries in recognizing stenoses of the extracranial part of the internal carotid artery (ICA). The examination was conducted by means of a specially designed vasotonometer in patients suffering from ischemic type cerebral circulatory disorders. The authors examined 98 patients and 20 healthy volunteers. The parameters of the diagnostic sensitivity of the method in various degrees and forms of the stenotic lesions of the ICA were determined. The correct diagnosis of a hemodynamically significant ICA stenosis was established in 85% of patients. The results of the examination were confirmed by angiography and operation.

Cerebral SPECT with 99mTc-HMPAO in extracranial carotid pathology: evaluation of changes in the ischemic area after carotid endarterectomy

The authors report their experience in studying patients undergoing carotid endarterectomy with simple photon emission computed tomography (SPECT). This technique made it possible to identify areas of preoperative cerebral hypoperfusion in 54.8% of the patients which had a good correlation with neurological symptoms. To distinguish gradual changes in the ischemic lesions, a method of assessing the surface of the hypoperfused areas was adopted. In addition, SPECT made it possible to detect a greater number of hypoperfused areas even in sites other than those revealed by CT. Moreover, there was good correlations between the SPECT data and the grade and site of the carotid lesion and the data provided by some intraoperative monitoring procedures. The Authors therefore propose the use of SPECT in the evaluation of patients with cerebrovascular insufficiency following a carotid disease.

Report of dissection of the internal carotid artery in three cases

Whereas previously the dissection of arteries leading to the brain was thought to be a rare occurrence, this diagnosis has been found more frequently in the last years as a result of newer imaging methods. Furthermore, in contrast to earlier opinions, there is a rather good prognosis for the recanalisation of the vessels and the restoration of the patient's health. In this paper, three cases with nearly typical constellation of symptoms and beneficial outcome are demonstrated. The related Doppler sonographical findings including duplex scan as well as the angiographical, computer tomographical and magnetic resonance tomography results are reported. It is to be noted that none of the three patients had a severe trauma or belonged to typical risk groups for a spontaneous dissection (Marfan's Syndrome, fibromuscular dysplasia.

Diagnostic value of automatically interpreted oculopneumoplethysmography

The diagnostic value of the Gee-oculopneumoplethysmography test for the detection of hemodynamically significant carotid artery obstructions has frequently been questioned due to the rather low agreement with arteriography. The kappa-corrected diagnostic accuracy of this test has been reported to be in the range between 0.54 and 0.68. These values indicate a "fair to good" agreement with arteriography. One of the causes for this rather low agreement is the variability in the interpretation of oculopneumoplethysmography recordings. Automatic analysis of oculopneumoplethysmography recordings might minimize the risks of misinterpretation and might improve the clinical significance of the Gee-oculopneumoplethysmography test. By assessing the signals of a conventional Gee-oculopneumoplethysmography apparatus in a personal computer, this automatic analysis has been realized. In a clinical study (population of 85 patients) the diagnostic value of automatic analysis of oculopneumoplethysmography recordings has been evaluated. The automatically interpreted Gee-oculopneumoplethysmography test had a kappa-corrected diagnostic accuracy of 0.71 on a "per side" base and of 0.76 on a "per patient" base.

Carotid artery stenosis: clinical efficacy of two-dimensional time-of-flight MR angiography

To assess the clinical efficacy of two-dimensional time-of-flight magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis, a group of patients was evaluated in which 73 vessels were studied with both MR and conventional angiography. Four experienced neuroradiologists each scored both the MR and conventional angiograms in a blinded manner by using a standardized scoring scheme. Comparison of the scores revealed a high degree of correlation. In particular, MR angiography served to discriminate reliably between mildly narrowed and severely narrowed or occluded vessels. Furthermore, severe stenoses were accurately discriminated from occlusions in all cases. MR angiography is a robust and accurate modality for the characterization of carotid artery stenosis. It is useful in conjunction with routine MR imaging of the brain in the evaluation of the patient with suspected carotid arterial disease.

Management of patients with asymptomatic neck bruits and carotid stenosis

The role of extracranial occlusive lesions in the pathogenesis of ischemic stroke is well established. The management of asymptomatic carotid bruit or stenosis is still highly controversial, however. This article reviews in detail the currently available data in order to assist clinicians in the management of patients with asymptomatic neck bruits or stenosis.

Assessment and management of carotid disease

Recent reports of results of clinical trials comparing carotid endarterectomy with medical treatment for carotid stenosis have clarified the relationship of extracranial carotid stenosis to symptomatic cerebrovascular disease. Results of these trials emphasize the importance of severity of carotid stenosis in therapeutic decision making. In addition, however, presence of carotid stenosis identifies individuals with an excess burden of cardiovascular disease risk factors and atherosclerosis of other (e.g. coronary) arteries. In parallel with growing awareness of the clinical relevance of extracranial carotid stenosis, new population-based studies and studies in symptomatic populations are defining the risk factors for extracranial carotid atherosclerosis and atherosclerosis progression. These new investigative approaches promise to increase substantially our understanding of the pathogenesis and clinical consequences of cerebrovascular disease in the forthcoming years.

Surgery for stroke: an update

Carotid endarterectomy was the most common vascular procedure in the USA in the 1980s. The last decade has witnessed a much-needed critical reappraisal of its role. Results from recent large-scale trials are now reported and will have a great influence on patient management.

[Stenosis of the internal carotid artery at the bifurcation. Radiologic definition and Doppler diagnosis]

One hundred internal carotid arteries with varying degrees of stenosis were studied by angiography and doppler ultrasound. We found the minimal diameter of a stenosis, measured in mm, more suitable as reference for the doppler-based method than verbal assessment of a stenosis as slight, moderate or pronounced. The sensitivity and specificity of maximal blood velocity to diagnose high-grade stenosis is satisfactory for screening patients who might benefit from endarterectomy. Spectral velocity spread, or comparison of the velocity in the stenosis with that of a cranial reference segment of the artery did not increase the sensitivity to detect low-grade stenoses.

Detection of internal carotid artery stenosis: comparison of MR angiography, color Doppler sonography, and arteriography

Findings of two-dimensional time-of-flight magnetic resonance (MR) angiography projection angiograms were prospectively compared with those of color Doppler sonography by using angiography as a standard in 23 consecutive patients (42 carotid bifurcations) to evaluate their utility in determining the presence of carotid artery stenosis. MR angiography helped detect 50% or greater lumen diameter stenosis (sensitivity, 0.96; specificity, 0.64). Color Doppler sonography with 1.25 m/sec peak systolic velocity as a threshold had a sensitivity of 0.96 and a specificity of 0.71. Statistical analysis showed a correlation between percentage of lumen diameter narrowing and the length of the zone of signal intensity loss with MR angiography (r = .69; P less than .0001). A stronger relationship was obtained between angiographic narrowing and peak systolic velocity derived from color Doppler sonography (r = .80; P less than .0001). Two-dimensional time-of-flight MR angiography displayed as projection angiograms and combined with carotid artery and combined with carotid artery sonography is a useful approach for helping detect and potentially grade the severity of stenoses of the carotid artery.

Dissection of cranial arteries in the neck: correlation of MRI and arteriography

Retrospective correlation of MRI and angiographic findings in nine patients with suspected cervical vascular dissections revealed MRI evidence of vessel abnormalities in eight patients, seven of whom proved to have arterial dissections. One patient whose MRI showed no abnormalities also proved to have a dissection, shown by angiography. Two patients had associated pseudoaneurysms not demonstrated by MRI. Five dissections involved the carotid arteries and three the vertebral arteries. Seven of the nine patients had associated transient neurologic deficits, while two had permanent deficits. Frank infarction of the brain was demonstrated by MRI in five cases. MRI findings suggestive of dissection included: (1) increased signal from the entire vessel; (2) a border of increased signal surrounding the lumen, with luminal narrowing; (3) poor or absent visualization of the vessel; and (4) significant compromise of the vessel lumen by adjacent abnormal increased signal tissue.

Quality of life and cognitive performance after carotid endarterectomy during long-term follow-up

The quality of life and the cognitive performance of patients with extracranial carotid stenosis were investigated 8-11 years after treatment in 18 non-operatively treated patients and 44 patients treated with carotid endarterectomy. The cognitive performance was compared with data on a normal control group. Cognitive performance was assessed with neuropsychological tests and the quality of life by personal interview based on a questionnaire. Most of the carotid stenosis patients recovered well both subjectively and cognitively regardless of the type of treatment. Only the subgroup operated twice was subjectively worse compared to the other groups. Even 10 years later the cognitive performance of carotid stenosis patients was remarkably close to normal.

Magnetic resonance angiography of extracranial carotid and vertebral arteries, including their origins: comparison with digital subtraction angiography

Although carotid bifurcation stenoses are not the only lesions of the extracranial cerebral arteries, magnetic resonance angiographic (MRA) studies to date have concentrated on the carotid bifurcation. We compared digital subtraction angiography of the extracranial portions of the cerebral arteries with MRA using an ordinary body coil, the time-of-flight method, and multiple transverse slabs which covered the arteries down to the aortic arch. Twenty-two patients (15 with arteriosclerotic diseases, 4 with aortitis, and 3 with tumours) had MRA using a 1.5 T magnet system with a three-dimensional fast imaging with steady state precession (FISP) technique. Thirty-nine carotid and 39 vertebral arteries were assessed by three radiologists with regard to stenoses or occlusions, graded as normal, mild (< 30%), moderate (30-60%) or severe (> 60%) stenosis, or occluded. Grading corresponded well in 81%; stenoses appeared more marked on MRA in 14% and were seen less clearly on MRA in 5%. When 26 carotid bifurcations were assessed separately, grading corresponded well in 95%. MRA is the only method which can display the whole course of the extracranial carotid and vertebral arteries non-invasively and satisfactorily.

Assessment of carotid artery stenosis by MR angiography: comparison with x-ray angiography and color-coded Doppler ultrasound

PURPOSE

To compare magnetic resonance angiography (MRA) with duplex Doppler ultrasound (US) and x-ray angiography (XRA) in the evaluation of the carotid bifurcation.

METHODS

The carotid arteries of 61 patients were studied using MRA, US, or XRA; 31 of the patients underwent all three examinations. MRA included both 2D and 3D time-of-flight sequences. Internal and external carotid artery origins were graded normal, mild, moderate, severe, or critical stenosis, or complete occlusion by each of the three studies.

RESULTS

Spearman rank correlations of both internal and external carotid artery grades were 0.85 (MRA and XRA), 0.69 (MRA and US), and 0.73 (XRA and US). For internal carotid artery origins only, the correlations were 0.94 (MRA and XRA), 0.85 (MRA and US), and 0.82 (XRA and US). Of discrepancies in internal carotid artery interpretation greater than one grade, seven resulted from US error, three from MRA error, and one from XRA error. A 2-cm partially thrombosed aneurysm detected by US and MRA was missed by XRA. Of 16 possible ulcers on XRA, 11 were noted by MRA, none by US.

CONCLUSIONS

MRA and XRA are similar in assessment of carotid bifurcation stenosis. MRA, like US, permits direct visualization of plaque. This preliminary study suggests that MRA may be used to clarify equivocal findings of US, or replace XRA in presurgical planning.

Detection of arterial intimal lesions: an experimental study comparing ultrasonography and arteriography

In an experimental study the diagnostic value of intra-operative ultrasonography in the detection of arterial intimal lesions was investigated. A human carotid artery was placed in a pulsatile circuit with a roller pump and tubes. Intimal lesions (1-5 mm) were created and ultrasonography and biplane arteriography were performed. The ultrasonograms and arteriograms obtained were interpreted by three observers, who were blind to the procedures performed and the results were compared to the macroscopic defects. The mean sensitivity between observers for ultrasonography was 84% with a specificity of 95.7%. For biplane arteriography the mean sensitivity was 42% with a specificity of 94.5%. The differences between ultrasonography and biplane arteriography were statistically significant (p less than 0.02). It is concluded from this is concluded from this in vitro study that ultrasonography provides more accurate information concerning intimal lesions of the arterial wall than biplane arteriography.

Progression to total occlusion is an underrecognized complication of the medical management of carotid disease

One potential complication of carotid disease is progression to total occlusion while under medical management. To investigate this important issue, 44 patients (31 men; 13 women) ranging in age from 44 to 83 (mean, 65.9) years with internal carotid artery occlusions as a result of arteriosclerosis were identified among 993 patients undergoing carotid angiography from Jan. 1, 1985 to Dec. 31, 1989, and their prior medical records were reviewed. Clinical presentations included stroke in 9 (20.5%), retinal infarct in 8 (18.2%), transient ischemic attacks in 10 (22.7%), amaurosis fugax in 4 (9.1%), nonhemispheric symptoms in 3 (6.8%), and 10 (22.7%) were asymptomatic. A review of these patients' medical records documented that prior hemispheric symptoms referrable to the now occluded internal carotid artery had occurred in five (55%) of the nine patients who were admitted with stroke, five (62%) of the eight patients with a retinal infarct, six (60%) of the 10 patients who were admitted with a transient ischemic attack, all four (100%) patients who were admitted with amaurosis fugax, one (33%) of three patients with nonhemispheric symptoms, and in seven (70%) of the 10 patients who were asymptomatic when the internal carotid artery occlusion was identified angiographically. In summary, 28 (64%) of the 44 patients had experienced ipsilateral symptoms from 2 to 120 (mean, 30) months before the diagnosis of internal carotid artery occlusion; only eight (28%) had undergone noninvasive or angiographic evaluation, and all were placed on antiplatelet therapy when prior hemispheric symptoms developed.(ABSTRACT TRUNCATED AT 250 WORDS)

Accelerated intracranial occlusive disease, oral contraceptives, and cigarette use

We report clinical and angiographic features of accelerated intracranial occlusive disease resembling moyamoya vasculopathy in five young women who used oral contraceptives (OCs) and smoked cigarettes, but generally had no other obvious risk factors for cerebrovascular disease. Three women had been on OCs for at least 4 years, one woman each had been on OCs for 3 months and for 2 weeks. All five women had smoked cigarettes for at least eight pack-years. Intermittent and progressive multifocal cognitive, visual, motor, or sensory hemispheric symptoms and signs developed in all. All patients developed strokes, four preceded by transient ischemic attacks. Cerebral angiography demonstrated bilateral supraclinoid internal carotid artery stenosis in four patients and proximal posterior cerebral artery stenosis in one. Additional features included rete mirabile, telangiectasias, prominent lenticulostriate collaterals, and multifocal distal cerebral branch occlusions. Three had mild abnormalities of serum fibrinogen, antinuclear antibody, erythrocyte sedimentation rate, or CSF IgG. After discontinuing OCs and reducing cigarette use, four women have not had further strokes over a mean follow-up of approximately 5 years. In certain young women, clinical and angiographic features resembling moyamoya may develop with the use of OCs and cigarettes. We speculate that an immunologically mediated vasculopathy may explain, in part, this unusual cerebrovascular syndrome in otherwise healthy young women.

[Diagnosis and prognosis of carotid artery stenosis]

The diagnosis of a carotid stenosis inevitably includes a neurological examination as well as CCT or MRI of the brain. Typical neurological and neuropsychological symptoms and signs as well as syndromes are described according to the vascular supply areas of the brain. CCT as well as MRI may identify cerebral infarction or other diseases and additionally give some information with regard to the underlying etiology or pathogenesis of an infarct. Satisfactory non-invasive demonstration of the carotid and vertebral arteries including their intracranial branches can be achieved by the use of sonographic methods (Dopplersonography, B-mode imaging, Duplex and colour-coded systems). Additionally, transcranial Dopplersonography is mandatory in most instances. Cerebral angiography is only justified preoperatively or for a disease which cannot be diagnosed reliably by other means, eg. cerebral venous thrombosis. The prognosis of a carotid stenosis depends not only on the degree of luminal narrowing and the shape of the stenosis but also on the clinical status of the patient (asymptomatic or symptomatic carotid stenosis, accompanying coronary artery disease etc.). Prophylactic treatment implies therapy of risk factors as well as antiaggregation, anticoagulation and carotid endarterectomy in selected cases.

Carotid stenosis in lacunar stroke

The prevalence of extracranial carotid stenosis in patients with a clinical syndrome of lacunar stroke has not been extensively studied using noninvasive methods. We performed carotid duplex sonography on 168 patients referred to the neurosonology laboratory with a diagnosis of ischemic stroke. Strokes were independently classified as lacunar or nonlacunar hemispheric infarction without knowledge of the ultrasound results. We excluded patients with infarcts that were clearly vertebrobasilar, presumed to be cardioembolic, or had occurred greater than 1 year earlier, and patients for whom classification of the nature and location of the event was not possible. Fifty-five patients had lacunar and 54 had nonlacunar stroke. No differences in age, sex, distribution, or prevalence of hypertension, diabetes, prior ischemia, or Hispanic surname existed between the two groups. Tobacco use was more frequent in the nonlacunar group (p less than 0.01). The prevalence of important extracranial carotid stenosis (greater than or equal to 50% diameter reduction) in the lacunar stroke group was 13% (seven of 55) in the ipsilateral and 4% (two of 55) in the contralateral carotid artery. Of the 54 patients with nonlacunar hemispheric stroke, 41% (22) had ipsilateral (p less than 0.01) and 26% (14) had contralateral (p less than 0.01) carotid stenosis. This study suggests that important carotid stenosis is infrequent among patients presenting with a clinical syndrome of lacunar stroke. These data impact on decisions regarding cerebrovascular work-up in such patients.

Comparison of Doppler CO2 test, patterns of infarction in CCT, and clinical symptoms in carotid artery occlusions

In patients with an internal carotid artery (ICA) occlusion the CO2 reactivity (autoregulatory reserve) is supposed to give information about the function of the collateral supply. To prove this hypothesis we compared the CO2 reactivity measured by transcranial Doppler sonography to the ipsilateral clinical symptoms and the patterns of infarction in cranial computed tomography (CCT). We studied 251 cases of ICA occlusion. Of the 141 cases with normal autoregulatory reserve, 37 (27%) had recently developed an ipsilateral neurological deficit. Of the 44 cases with exhausted CO2 reactivity, 28 (64%) had experienced an event. The difference is highly significant (p less than 0.0001). In 59 of the 75 patients for whom CCT images were available, we found signs of vascular-ischemic lesions. Of the 30 patients with hemodynamic infarctions, 13 showed an exhausted autoregulatory reserve, while of 19 cases with territorial infarctions only 1 and of 10 with lacunar infarctions none had an exhausted CO2 reactivity. The difference is significant (p less than 0.01).

Noninvasive evaluation of asymptomatic carotid bruits

Proper clinical management of a patient found to have an asymptomatic carotid bruit continues to be controversial, with wide differences of opinion concerning the advisability of angiography and surgery. A noninvasive cerebrovascular evaluation is described, which combines three separate but complimentary procedures: ocular pneumoplethysmography (OPPG), carotid audiofrequency analysis (CAA), and cerebral Doppler analysis. Such studies are particularly helpful in evaluating patients with an asymptomatic carotid bruit. The reliability and effectiveness of this approach was evaluated in a series of 165 consecutive patients with an asymptomatic bruit. Angiography was recommended in patients with positive results (42%) and safely withheld in those with negative findings (58%). There were two false-positive results and only one known false-negative interpretation.