Classification and treatment of spontaneous carotid-cavernous sinus fistulas

An anatomical-angiographic classification for carotid-cavernous sinus fistulas is introduced and a series of 14 patients with spontaneous carotid-cavernous sinus fistulas is reviewed to illustrate the usefulness of such a classification for patient evaluation and treatment. Fistulas are divided into four types: Type A are direct high-flow shunts between the internal carotid artery and the cavernous sinus; Type B are dural shunts between meningeal branches of the internal carotid artery and the cavernous sinus; Type C are dural shunts between meningeal branches of the external carotid artery and the cavernous sinus; and Type D are dural shunts between meningeal branches of both the internal and external carotid arteries and the cavernous sinus. The anatomy, clinical manifestations, angiographic evaluation, indications for therapy, and therapeutic options for spontaneous carotid-cavernous sinus fistulas are discussed.

Classification of human carotid atherosclerotic lesions with in vivo multicontrast magnetic resonance imaging

BACKGROUND

Recent studies demonstrated that in vivo and ex vivo MRI can characterize the components of the carotid atherosclerotic plaque, such as fibrous tissue, lipid/necrotic core, calcium, hemorrhage, and thrombus. The purpose of this study was to determine whether in vivo high-resolution multicontrast MRI could accurately classify human carotid atherosclerotic plaque according to the American Heart Association classification.

METHODS AND RESULTS

Sixty consecutive patients (mean age 70 years; 54 males) scheduled for carotid endarterectomy were imaged with a 1.5-T scanner after informed consent was obtained. A standardized protocol was used to obtain 4 different contrast-weighted images (time of flight and T1-, PD-, and T2-weighted) of the carotid arteries. Best voxel size was 0.25x0.25x1 mm3. Carotid plaques were removed intact and processed for histological examination. Both MR images and histological sections were independently reviewed, categorized, and compared. Overall, the classification obtained by MRI and the American Heart Association classifications showed good agreement, with Cohen's kappa (95% CI) of 0.74 (0.67 to 0.82) and weighted kappa of 0.79. The sensitivity and specificity, respectively, of MRI classification were as follows: type I-II lesions, 67% and 100%; type III lesions, 81% and 98%; type IV-V lesions, 84% and 90%; type VI lesions, 82% and 91%; type VII lesions, 80% and 94%; and type VIII lesions, 56% and 100%.

CONCLUSIONS

In vivo high-resolution multicontrast MRI is capable of classifying intermediate to advanced atherosclerotic lesions in the human carotid artery and is also capable of distinguishing advanced lesions from early and intermediate atherosclerotic plaque.

Accumulation of ultrasmall superparamagnetic particles of iron oxide in human atherosclerotic plaques can be detected by in vivo magnetic resonance imaging

BACKGROUND

One of the features of high-risk atherosclerotic plaques is a preponderance of macrophages. Experimental studies with hyperlipidemic rabbits have shown that ultrasmall superparamagnetic particles of iron oxide (USPIOs) accumulate in plaques with a high macrophage content and that this induces magnetic resonance (MR) signal changes. The purpose of our study was to investigate whether USPIO-enhanced MRI can also be used for in vivo detection of macrophages in human plaques.

METHODS AND RESULTS

MRI was performed on 11 symptomatic patients scheduled for carotid endarterectomy before and 24 (n=11) and 72 (n=5) hours after administration of USPIOs (Sinerem) at a dose of 2.6 mg Fe/kg. Histological and electron microscopical analyses of the plaques showed USPIOs primarily in macrophages within the plaques in 10 of 11 patients. Histological analysis showed USPIOs in 27 of 36 (75%) of the ruptured and rupture-prone lesions and 1 of 14 (7%) of the stable lesions. Of the patients with USPIO uptake, signal changes in the post-USPIO MRI were observed by 2 observers in the vessel wall in 67 of 123 (54%) and 19 of 55 (35%) quadrants of the T2*-weighted MR images acquired after 24 and 72 hours, respectively. For those quadrants with changes, there was a significant signal decrease of 24% (95% CI, 33% to 15%) in regions of interest in the images acquired after 24 hours, whereas no significant signal change was found after 72 hours.

CONCLUSIONS

Accumulation of USPIOs in macrophages in predominantly ruptured and rupture-prone human atherosclerotic lesions caused signal decreases in the in vivo MR images.

Carotid plaque area: a tool for targeting and evaluating vascular preventive therapy

BACKGROUND AND PURPOSE

Carotid plaque area measured by ultrasound (cross-sectional area of longitudinal views of all plaques seen) was studied as a way of identifying patients at increased risk of stroke, myocardial infarction, and vascular death.

METHODS

Patients from an atherosclerosis prevention clinic were followed up annually for up to 5 years (mean, 2.5+/-1.3 years) with baseline and follow-up measurements recorded. Plaque area progression (or regression) was defined as an increase (or decrease) of >/=0.05 cm(2) from baseline.

RESULTS

Carotid plaque areas from 1686 patients were categorized into 4 quartile ranges: 0.00 to 0.11 cm(2) (n=422), 0.12 to 0.45 cm(2) (n=424), 0.46 to 1.18 cm(2) (n=421), and 1.19 to 6.73 cm(2) (n=419). The combined 5-year risk of stroke, myocardial infarction, and vascular death increased by quartile of plaque area: 5.6%, 10.7%, 13.9%, and 19.5%, respectively (P<0.001) after adjustment for all baseline patient characteristics. A total of 1085 patients had >/=1 annual carotid plaque area measurements: 685 (63.1%) had carotid plaque progression, 306 (28.2%) had plaque regression, and 176 (16.2%) had no change in carotid plaque area over the period of follow-up. The 5-year adjusted risk of combined outcome was 9.4%, 7.6%, and 15.7% for patients with carotid plaque area regression, no change, and progression, respectively (P=0.003).

CONCLUSIONS

Carotid plaque area and progression of plaque identified high-risk patients. Plaque measurement may be useful for targeting preventive therapy and evaluating new treatments and response to therapy and may improve cost-effectiveness of secondary preventive treatment.

Indications for treatment and classification of 132 carotid-cavernous fistulas

Classification of carotid-cavernous fistulas (CCFs) into the four types described by Barrow allows the surgeon to choose the optimal therapy for each patient. Type A patients have fast flow fistulas that are manifest by a direct connection between the internal carotid arterial siphon and the cavernous sinus through a single tear in the arterial wall. The best therapy is obliteration of the connection by a detachable balloon. Ninety-two of 95 traumatic CCFs were treated in this fashion. Direct surgical exposure of the cervical or cavernous internal carotid artery (ICA) was necessary in the remaining 3 patients, who had undergone unsuccessful surgical trapping. Three ruptured cavernous aneurysms and 2 spontaneous CCFs also had Type A connections. Other carotid-cavernous fistulas are slow flow, spontaneous dural arteriovenous malformations (AVMs) that have been classified into B, C, and D types on the basis of arterial supply. Occlusion of the ICA is not a logical choice in the treatment of dural AVMs that occur in the elderly, are relatively benign, and are often bilateral. Type B are rare and are fed by meningeal branches of the ICA only. We have not seen this type of dural fistula in our series. Type C are supplied by feeders from the external carotid only and can almost always be obliterated successfully by embolizing the external carotid artery (ECA) branches. There are 4 Type C cases in this series of 37 spontaneous CCFs. All occurred in patients less than 30 years of age and were shunts between the middle meningeal artery and the cavernous sinus.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and angiographic features of carotid transient ischemic attacks

To determine the prevalence of radiologically evident carotid stenosis in patients with transient cerebral ischemic attacks, we analyzed 95 consecutive hospitalized patients who during a two-year period had appropriate symptoms and also underwent angiography. Pure transient hemisphere symptoms affected 52 patients, pure monocular blindness occurred in 33, and 10 experienced each type of attack separately. Tight stenosis (less than or equal to 2 mm) or occlusion was present in 49 patients (52 per cent). Thirteen patients showed intracranial-branch occlusion, nine of whom had no notable stenosis. Only two clinical transient ischemic attack features correlated with angiographic findings: in transient hemisphere attacks lasting for one hour or longer, the carotid arteries revealed no notable stenosis (0.05 less than P less than 0.1); and separate hemisphere and ocular attacks in the same patient correlated with tight carotid stenosis. On the basis of the angiographic findings, the study indicates there are several distinct groups of patients with carotid transient ischemic attacks.

Artery-Related Differences in Atherosclerosis Expression

Background and Purpose— Information about the expression of atherosclerosis in different arteries is important. The impact of cardiovascular risk factors is artery-related, and the assessment of arterial structure and function in peripheral arteries are increasingly used as surrogate markers for coronary atherosclerosis and the risk of developing heart attack.

Methods— In an autopsy study, we analyzed the coronary, carotid and superficial femoral arteries from 100 individuals (70 men; 20 to 82 years of age) of which 27 died from coronary atherosclerosis. Microscopic sections (n=4756) were analyzed blindly using a modification of the histological classification endorsed by the American Heart Association (AHA).

Results— We found distinct artery-dependent patterns of atherosclerosis with a high prevalence of foam cell lesions and lipid core plaques in the carotid arteries. The femoral arteries were least affected by atherosclerosis, foam cell lesions were rare, and the development of advanced atherosclerosis was strongly age-dependent and dominated by fibrous plaques. Plaques were most common in the left anterior descending coronary artery and the carotid bifurcation. In coronary (versus noncoronary) death, lipid core plaques were more prevalent in all arteries.

Conclusions— The initiation, speed of development, and phenotypic expression of atherosclerotic plaques are artery-related. Foam cell lesions are frequent in the carotid arteries, probably explaining the dynamics in carotid intima-media thickness. Atherosclerosis develops slowly in femoral arteries, and severe atherosclerosis is dominated by fibrous plaques. The higher prevalence of lipid core plaques in all arteries in coronary death indicates a systemically more vulnerable expression of atherosclerosis in these individuals.

Quantitative assessment of carotid plaque composition using multicontrast MRI and registered histology

MRI is emerging as a promising modality for monitoring carotid atherosclerosis. Multiple MR contrast weightings are required for identification of plaque constituents. In this study, eight MR contrast weightings with proven potential for plaque characterization were used to image carotid endarterectomy specimens. A classification technique was developed to create a tissue-specific map by incorporating information from all MR contrast weightings. The classifier was validated by comparison with micro-CT (calcification only) and with matched histological slices registered to MR images using a nonlinear warping algorithm (other components). A pathologist who was blinded to the classifier results manually segmented digitized histological images. The sensitivity of the classifier, as determined by pixel-by-pixel comparison with the pathologist's segmentation and micro-CT, was 60.4% for fibrous tissue, 83.9% for necrosis, 97.6% for calcification, and 65.2% for loose connective tissue. The corresponding values for specificity were 87.9%, 75.0%, 98.3%, and 94.9%, respectively. In conclusion, multicontrast MRI was successfully used in conjunction with a supervised classification algorithm to identify plaque components in endarterectomy specimens. Furthermore, this methodology will provide a framework for comparing different classification algorithms, and determining which combination of MR contrasts will be most valuable for in vivo plaque imaging.

Computed tomography angiography for the evaluation of carotid atherosclerotic plaque: correlation with histopathology of endarterectomy specimens

BACKGROUND AND PURPOSE

The goal of this study was to determine the efficacy of CT angiography for the characterization of plaque morphology and composition in carotid atherosclerotic disease.

METHODS

Fifty-five patients undergoing carotid endarterectomy were imaged preoperatively with single-slice spiral CT angiography. One hundred sixty-five endarterectomy sections were examined histologically at selected levels through the distal common and proximal internal carotid arteries. Plaque density was measured (in Hounsfield units) on axial CT sections, and the presence or absence of ulceration was noted. These observations were compared with the histological findings at corresponding levels. Data were analyzed with 2-sample t tests and 1-way analysis of variance (ANOVA).

RESULTS

ANOVA testing showed a statistically significant decrease in CT attenuation values with increasing plaque lipid but with a very high standard deviation of values. No other histological factor showed a statistically significant link with CT attenuation. Plaque ulceration was detected by CT with a sensitivity of 60% and a specificity of 74%.

CONCLUSIONS

Analysis of plaque attenuation with single-slice spiral CT does not give useful information concerning plaque composition. The predictive value of CT for the detection of plaque ulceration was moderate. Single-slice CT angiography is insufficiently robust to be a useful tool for the characterization of carotid plaque composition and morphology.

Recurrence of ICA-PCoA aneurysms after neck clipping

Between 1975 and 1992, 2211 patients underwent aneurysmal neck clipping at the Nara Medical University clinic and associated hospitals. The aneurysm in 931 of these patients was situated at the junction of the internal carotid artery (ICA) and posterior communicating artery (PCoA). Seven patients were readmitted 4 to 17 years after the first surgery because of regrowth and rupture of an ICA-PCoA aneurysmal sac that had arisen from the residual neck. On angiograms obtained following aneurysmal neck clipping, a large primitive type of PCoA was demonstrated in six patients and a small PCoA in one. A small residual aneurysm was confirmed in only two patients and angiographically complete neck clipping in five. Recurrent ICA-PCoA aneurysms were separated into two types based on the position of the old clip in relation to the new growth. Type 1 aneurysms regrow from the entire neck and balloon eccentrically. In this type, it is possible to apply the clip at the neck as in conventional clipping for a ruptured aneurysm. Type 2 includes aneurysms in which the proximal portion of a previous clip is situated at the corner of the ICA and aneurysmal neck and the distal portion on the enlarged dome of the aneurysm, because the sac is regrowing from a portion of the residual neck. In this type of aneurysm, a Sugita fenestrated clip can occlude the residual neck, overriding the old clip. Classifying these aneurysms into two groups is very useful from a surgical point of view because it is possible to apply a new clip without removing the old clip, which was found to be adherent to surrounding tissue.

Correlation between wave components of the second derivative of plethysmogram and arterial distensibility

The ratio of two wave components (magnitude of b/a constituting the second derivative of the plethysmogram (SDPTG) was correlated with arterial distensibility. Eighty-two subjects (33-93 years old) were classified into three groups according to the thickness of the intima-media complex of the common carotid artery measured by B-mode ultrasonography. One group was non-atherosclerotic (without pathologic thickening) (nAS) and the other two groups atherosclerotic (mild and severe thickening, or plaque formation) (AS-1 and AS-2). Distensibility (D) of the common carotid artery was calculated from arterial dimensions and blood pressure: h/p = D, where h = (Ds-Dd)/Dd; Ds, Dd and p represent the inner diameter of the carotid artery at peak systole, at end diastole and brachial pulse pressure, respectively. The plethysmogram was recorded at the cuticle of the 2nd digit of the left hand, and the SDPTG was determined with a 10 msec time constant. D showed a significant negative correlation with age in all subjects and in the three separate groups. The correlation between age and magnitude of b/a was significantly negative in all subjects. This negative correlation was not observed in the nAS group, while it was significant in both AS-1 and AS-2. The correlation between magnitude of b/a and D was significantly positive in all subjects and in each group. Significant differences were found among the three groups for magnitude of b/a and D. These results suggest that a decrease in magnitude of b/a or in D was proportional to the thickness of the intima-media complex of the carotid artery, that is, the development of atherosclerosis. These results provide direct evidence that magnitude of b/a of the SDPTG is related to the distensibility of the peripheral artery, and suggest that magnitude of b/a is a useful non-invasive index of atherosclerosis and altered arterial distensibility.

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.

Classification of aneurysms of the internal carotid system

Microsurgery has improved the treatment of cerebral aneurysms techically and by more detailed knowledge of the topographic relations, the variations, and the anomalies of the involved arteries. A personal study of 450 aneurysms formed the basis of a modified and more detailed classification of aneurysms of the carotid system. It was confirmed that aneurysms originate at the junctions of arteries, and generally project according to the course of the vessel involved. The origins and projections aneurysms and their different sites were analyzed with the aid of angiography, angiotomography, magnification angiography, operative drawings, photographs, and films, which permitted the establishment of a special classification for every particular form. Preoperative knowledge of the types of aneurysms facilitates the surgical procedures and results in lowered morbidity.

Multi-Slice CT Angiography in Diagnosing Total Versus Near Occlusions of the Internal Carotid Artery

BACKGROUND AND PURPOSE

To determine the accuracy of multislice computed tomographic (CT) angiography in diagnosing total versus near occlusions of the internal carotid artery (ICA).

METHODS

Fifty-seven ICA total or near occlusions identified by catheter angiography were studied with multislice CT angiography 1 to 3 days after catheter angiography. CT angiography in diagnosing total versus near occlusions was analyzed by 2 radiologists independently. The results were compared with those of catheter angiography.

RESULTS

Catheter angiography depicted 31 total occlusions, including 10 without a stump, 19 with a stump <2 cm, and 2 with a stump >2 cm. Among them, 22 had a downward extent of the retrograde ICA flow at or above the carotid siphon, 8 at the carotid canal, and 1 at the distal cervical ICA. Catheter angiography depicted 26 near occlusions, including 21 with a tight stenosis at the proximal third cervical ICA, 1 at the middle third, and 4 at the carotid canal or siphon. CT angiography correctly depicted all total and near occlusions. In total occlusions, the length of the stump and the retrograde flow were all accurately described by CT angiography. In near occlusions, the sites of tight stenoses were also correctly identified by CT angiography.

CONCLUSIONS

Multislice CT angiography had an excellent correlation with catheter angiography in diagnosing total versus near occlusion of the ICA. It may be considered as a substitute of catheter angiography in confirming the ultrasonographic results in diagnosing total versus near occlusions of the ICA.

Contrast-enhanced magnetic resonance angiography of carotid arteries: utility in routine clinical practice

BACKGROUND AND PURPOSE

Contrast-enhanced magnetic resonance angiography (CEMRA) is among the newer noninvasive tests used for the evaluation of patients with carotid artery disease. Evidence supporting its utility in routine clinical practice is lacking.

METHODS

The results of CEMRA were compared with those of catheter angiography in 50 consecutive patients being evaluated for carotid endarterectomy (CEA) at a community hospital. Using indications for CEA based on published guidelines, we determined the rate of misclassification for surgery, sensitivity, specificity, and positive and negative predictive values. In addition, the interrater agreement (kappa score) of CEMRA was compared with that of catheter angiography in the studied population and with interpretations provided by 2 blinded radiologists.

RESULTS

Compared with catheter angiography, 24% (95% CI, 12% to 36%) of patients would have been misclassified for CEA on the basis of CEMRA results alone. CEMRA was associated with sensitivity of 92%, specificity of 62%, positive predictive value of 78%, and negative predictive value of 89%. When both CEMRA and duplex Doppler ultrasound were performed and the results were concordant, the misclassification rate decreased to 17% (95% CI, 2% to 32%). kappa scores were similar for CEMRA and catheter angiography (0.72 and 0.75, respectively).

CONCLUSIONS

CEMRA was found to be highly sensitive for detection of surgically amenable carotid stenosis. kappa scores for the interpretation of CEMRA and catheter angiography were similar. However, clinicians should be cautious when using CEMRA alone for surgical decision making in CEA candidates because a significant number of patients may be misclassified. The rate of misclassification is reduced when the results of CEMRA and duplex Doppler ultrasound are concordant.

In-vivo quantitative T2 mapping of carotid arteries in atherosclerotic patients: segmentation and T2 measurement of plaque components

BACKGROUND

Atherosclerotic plaques in carotid arteries can be characterized in-vivo by multicontrast cardiovascular magnetic resonance (CMR), which has been thoroughly validated with histology. However, the non-quantitative nature of multicontrast CMR and the need for extensive post-acquisition interpretation limit the widespread clinical application of in-vivo CMR plaque characterization. Quantitative T2 mapping is a promising alternative since it can provide absolute physical measurements of plaque components that can be standardized among different CMR systems and widely adopted in multi-centre studies. The purpose of this study was to investigate the use of in-vivo T2 mapping for atherosclerotic plaque characterization by performing American Heart Association (AHA) plaque type classification, segmenting carotid T2 maps and measuring in-vivo T2 values of plaque components.

METHODS

The carotid arteries of 15 atherosclerotic patients (11 males, 71 ± 10 years) were imaged at 3 T using the conventional multicontrast protocol and Multiple-Spin-Echo (Multi-SE). T2 maps of carotid arteries were generated by mono-exponential fitting to the series of images acquired by Multi-SE using nonlinear least-squares regression. Two reviewers independently classified carotid plaque types following the CMR-modified AHA scheme, one using multicontrast CMR and the other using T2 maps and time-of-flight (TOF) angiography. A semi-automated method based on Bayes classifiers segmented the T2 maps of carotid arteries into 4 classes: calcification, lipid-rich necrotic core (LRNC), fibrous tissue and recent IPH. Mean ± SD of the T2 values of voxels classified as LRNC, fibrous tissue and recent IPH were calculated.

RESULTS

In 37 images of carotid arteries from 15 patients, AHA plaque type classified by multicontrast CMR and by T2 maps (+ TOF) showed good agreement (76% of matching classifications and Cohen's κ = 0.68). The T2 maps of 14 normal arteries were used to measure T2 of tunica intima and media (T2 = 54 ± 13 ms). From 11865 voxels in the T2 maps of 15 arteries with advanced atherosclerosis, 2394 voxels were classified by the segmentation algorithm as LRNC (T2 = 37 ± 5 ms) and 7511 voxels as fibrous tissue (T2 = 56 ± 9 ms); 192 voxels were identified as calcification and one recent IPH (236 voxels, T2 = 107 ± 25 ms) was detected on T2 maps and confirmed by multicontrast CMR.

CONCLUSIONS

This carotid CMR study shows the potential of in-vivo T2 mapping for atherosclerotic plaque characterization. Agreement between AHA plaque types classified by T2 maps (+TOF) and by conventional multicontrast CMR was good, and T2 measured in-vivo in LRNC, fibrous tissue and recent IPH demonstrated the ability to discriminate plaque components on T2 maps.

Radiometric analysis of paraclinoid carotid artery aneurysms

OBJECT

Classification of paraclinoid carotid artery (CA) aneurysms based on their associated branching arteries has been confusing because superior hypophyseal arteries (SHAs) are too fine to appear opacified on cerebral angiograms. The authors performed a retrospective radiometric analysis of surgically treated paraclinoid aneurysms to elucidate their angiographic and anatomical characteristics.

METHODS

A retrospective analysis was made of 85 intradural paraclinoid aneurysms in which the presence or absence of branching arteries had been determined at the time of surgical clipping. The lesions were classified as supraclinoid, clinoid, and infraclinoid aneurysms based on their relation to the anterior clinoid process on lateral angiograms of the CA. The direction of the aneurysms were measured according to angles formed between the medial portion of the horizontal line crossing the aneurysm sac and the center of the aneurysm neck on anteroposterior angiograms. Branching arteries were associated with 68 aneurysms, of which 28 were ophthalmic artery (OphA) lesions (32.9%) and 40 were SHA ones (47.1%); associated branching arteries were absent in 17 aneurysms (20%). Twenty-five aneurysms (29.4%) were located at the supraclinoidal level, 46 (54.1%) at the clinoidal, and 14 (16.5%) at the infraclinoidal. The majority of aneurysms identified at the supraclinoidal level were OphA lesions (44%) or those unassociated with branching arteries (48%), with mean directions of 57 degrees or 67 degrees, respectively. At the clinoidal level, the mean directions of aneurysms were 76 degrees in six lesions unassociated with branching arteries (13%), 43 degrees in 16 OphA lesions (35%), and -11 degrees in 24 SHA ones (52%). All aneurysms at the infraclinoidal level arose at the origin of the SHAs, with a mean direction of -29 degrees, and most of these were embedded in the carotid cave.

CONCLUSIONS

Aneurysms arising from the SHA can be distinguished from those not located at an arterial division by cerebral angiography, because SHA lesions are usually located at the medial or inferomedial wall of the internal carotid artery at the clinoidal or infraclinoidal level. Their distribution correlates well with the reported distribution of SHA origins. The carotid cave aneurysm is a kind of SHA lesion that originates at the most proximal intradural CA.

Carotid thromboendarterectomy: a reappraisal. Criteria for patient selection

Thromboendarterectomy performed in 35 patients with symptoms distal and ipsilateral to an occluded internal carotid artery resulted in patency in 19 cases (53%). Two factors that influence successful operation are early intervention following occlusion and good collateral circulation. In only 12 patients (34%) could the interval from occlusion to surgery be confidently determined. Four of these vessels, occluded for up to 7 days (100%), and five of eight vessels (63%), occluded for up to 4 weeks, were reopended. In the remaining patients, where the duration of occlusion was indefinite, greater reliance was placed on the evaluation and grading of angiographic collateral supply distal to the occlusion. Patients with Grade 1 to 3 collateral supply should not be explored unless occlusion occurred very recently. Patients with Grades 4 and 5 collateral supply are considered for carotid exploration regardless of the duration of the occlusion, as an alternative to other methods of revascularization.

Association between uric acid and carotid atherosclerosis in elderly persons

OBJECTIVE

Several cohort studies have shown a link between serum uric acid (SUA) and subsequent cardiovascular disease. However, such an association did not remain significant after adjusting for concomitant risk factors for atherosclerosis in some studies. Thus, the role of SUA as an independent risk factor remains controversial. We therefore investigated the association between SUA and sclerotic lesions of common carotid atherosclerosis.

PATIENTS AND METHODS

We evaluated sclerotic lesions of the common carotid arterial intima-media thickness (IMT) by ultrasonography in 398 men aged 74+/-8 (range, 60-97) years and 521 women aged 75+/-8 (range, 60-104) years. To investigate the relation between SUA and various factors, all subjects were divided into three groups based on the tertile of SUA.

RESULTS

Stepwise multiple linear regression analysis using IMT as an objective variable, adjusted by various risk factors as explanatory variables showed that SUA [B, 0.0099; 95% confidence interval (CI), 0.0022-0.0175] was a significant independent contributing factor along with known risk factors such as age, sex, smoking status, systolic blood pressure, diastolic blood pressure, antihypertensive drug use, HDL-cholesterol, and LDL-cholesterol. Multiple logistic regression analysis for carotid IMT as a tertile of SUA and dependent variables showed that the adjusted odds ratio was 1.25 (95% CI, 0.87-1.78) for those in the middle tertile (4.2-5.5 mg/dl), and 1.66 (95% CI, 1.16-2.39) for those in the highest tertile (5.6-14.1 mg/dl) compared to that for subjects in the lowest tertile of SUA levels (0.51-4.1 mg/dl).

CONCLUSION

We suggest that SUA is a risk factor or marker for ultrasonographically determined IMT.

Determination of carotid artery atherosclerotic lesion type and distribution in hypercholesterolemic patients with moderate carotid stenosis using noninvasive magnetic resonance imaging

BACKGROUND AND PURPOSE

The aims of this study were to noninvasively determine carotid atherosclerotic lesion type and distribution and to evaluate the reproducibility of determining lesion types in asymptomatic patients with moderate hypercholesterolemia and moderate carotid artery (CA) stenosis using MRI.

METHODS

Forty-two asymptomatic patients with moderate CA stenosis underwent bilateral carotid MRI in a 1.5-T scanner using a protocol that generated 4 contrast weightings (T1, T2, proton density, and 3D time of flight). MRI-modified American Heart Association criteria were used to evaluate lesion types at 3 locations (common and internal CA [CCA and ICA, respectively] and CA bifurcation) and at the minimum lumen area. Two identical MR scans were conducted to evaluate reproducibility of lesion types.

RESULTS

Lesion types were obtained from 230 locations. Type III (39%) occurred most commonly, followed by types IV-V (25%), I-II (20%), VI (12%), and VII (4%). Type III was more commonly distributed in the CCA (n=35, 39%) and ICA (n=32, 36%). Type IV-V was more commonly distributed in the CCA (n=24, 41%) and at the bifurcation (n=21, 36%). Forty-two lesions were available at the site of minimum lumen area: type III (33%), IV-V (33%), VI (29%), and VII (5%). There was good agreement of lesion types between both MRI scans (Cohen's kappa=0.73; 95% CI: 0.65 to 0.81).

CONCLUSIONS

MRI can determine lesion types reproducibly as well as the distribution of lesions in hypercholesterolemic patients with moderate CA stenosis. A wide range of lesion types, including advanced lesions, were found in these patients.

Computer based pattern recognition of carotid arterial disease using pulsed Doppler ultrasound

A minicomputer based system has been developed for studying carotid artery blood flow data obtained for a combined B-mode, pulsed Doppler ultrasound scanner. The goals of this work are to devise and improve techniques for estimating the extent of atherosclerosis at the carotid artery bifurcation. Features are automatically extracted from spectrum analyzed Doppler blood flow data. Five statistical pattern recognition algorithms are compared, with cross validation being used to improve the estimate of classification accuracy. A data collection protocol has been devised in which four sites are studied along each carotid arterial system. Classification of unknowns is done using a hierarchy of three decisions.

Computer based classification of carotid arterial disease: a prospective assessment

A minicomputer based pattern recognition method has been used to prospectively classify the category of disease involvement of 105 carotid arteries. The system utilized spectral patterns obtained from a combined B-mode/pulsed Doppler unit. All decisions are based upon comparison of an unknown, averaged waveform with a series of vessels with known severity of disease. The variability in the computer decision as compared to arteriography is discussed.

Diagnosis of carotid-cavernous fistulas with magnetic resonance angiography--demonstrating the draining veins utilizing 3-D time-of-flight and 3-D phase-contrast techniques

This study assessed the ability to diagnose carotid-cavernous fistulas (CCFs) non-invasively using magnetic resonance angiography (MRA). Both three-dimensional time-of-flight (3-D TOF) MRA and three-dimensional phase-contrast (3-D PC) MRA were compared with conventional cerebral angiography in nine patients with CCFs. CCFs were grouped according to Barrow's classification. In all cases, 3-D TOF MRA revealed an inferior petrosal sinus as a draining vein. 3-D PC MRA demonstrated a dilated and tortuous superior ophthalmic vein (SOV) and reflux of the SOV in seven patients. In conclusion, CCFs can be diagnosed with MRA alone by demonstrating the drainging veins.

Reproducibility of Carotid Atherosclerotic Lesion Type Characterization Using High Resolution Multicontrast Weighted Cardiovascular Magnetic Resonance

PURPOSE

Cardiovascular magnetic resonance (CMR) can characterize carotid atherosclerosis. The purpose of this study is to evaluate reader agreement of carotid atherosclerotic lesion types by CMR.

METHODS

Carotid arteries of 34 patients (29 men, 5 women; mean age, 53 years) were imaged on a 1.5-T scanner. Images with 4 contrast weightings (T1, T2, proton density, and 3-dimensional time-of-flight) were acquired on each axial slice of the carotid arteries. Modified AHA criteria were used for lesion type assessment on the 4 selected axial slices (1 from the common carotid artery, 1 from the carotid bifurcation, and 2 from the internal carotid artery). The modified AHA criteria are as follows: type I-II, near-normal wall thickness without calcification; type III, diffuse wall thickening or small eccentric plaque without calcification; type IV-V, plaque with a lipid rich necrotic core surrounded by fibrous tissue with possible calcification; type VI, complex plaque with a possible surface defect, hemorrhage, or thrombus; type VII, calcified plaque; and type VIII, fibrotic plaque without a lipid core and with possible small calcifications.

RESULTS

Of the 272 possible axial slices (34 patients x 2 arteries per patient x 4 slices per artery), 256 slices were available for lesion type assessment. The majority (94%) of the lesions were of type I-II and III. kappa was 0.80 and 0.60 for intra-reader and inter-reader agreement of lesion types, respectively. Inter-reader disagreement for type I-II and type III occurred in 82% of lesions. Weighted kappa was 0.92 and 0.83 for intra-reader and inter-reader agreement of lesion types, respectively.

CONCLUSION

The difference between type I-II and III lesions lies in the definition of the vessel wall. The moderate inter-reader agreement suggests further efforts such as establishment of normal carotid artery wall thickness by a quantitative measure are needed for carotid atherosclerotic lesion characterization.