Vascular contributions to cognitive impairment and dementia: a statement for healthcare professionals from the american heart association/american stroke association

BACKGROUND AND PURPOSE

This scientific statement provides an overview of the evidence on vascular contributions to cognitive impairment and dementia. Vascular contributions to cognitive impairment and dementia of later life are common. Definitions of vascular cognitive impairment (VCI), neuropathology, basic science and pathophysiological aspects, role of neuroimaging and vascular and other associated risk factors, and potential opportunities for prevention and treatment are reviewed. This statement serves as an overall guide for practitioners to gain a better understanding of VCI and dementia, prevention, and treatment.

METHODS

Writing group members were nominated by the writing group co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council Scientific Statement Oversight Committee, the Council on Epidemiology and Prevention, and the Manuscript Oversight Committee. The writing group used systematic literature reviews (primarily covering publications from 1990 to May 1, 2010), previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. After peer review by the American Heart Association, as well as review by the Stroke Council leadership, Council on Epidemiology and Prevention Council, and Scientific Statements Oversight Committee, the statement was approved by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

The construct of VCI has been introduced to capture the entire spectrum of cognitive disorders associated with all forms of cerebral vascular brain injury-not solely stroke-ranging from mild cognitive impairment through fully developed dementia. Dysfunction of the neurovascular unit and mechanisms regulating cerebral blood flow are likely to be important components of the pathophysiological processes underlying VCI. Cerebral amyloid angiopathy is emerging as an important marker of risk for Alzheimer disease, microinfarction, microhemorrhage and macrohemorrhage of the brain, and VCI. The neuropathology of cognitive impairment in later life is often a mixture of Alzheimer disease and microvascular brain damage, which may overlap and synergize to heighten the risk of cognitive impairment. In this regard, magnetic resonance imaging and other neuroimaging techniques play an important role in the definition and detection of VCI and provide evidence that subcortical forms of VCI with white matter hyperintensities and small deep infarcts are common. In many cases, risk markers for VCI are the same as traditional risk factors for stroke. These risks may include but are not limited to atrial fibrillation, hypertension, diabetes mellitus, and hypercholesterolemia. Furthermore, these same vascular risk factors may be risk markers for Alzheimer disease. Carotid intimal-medial thickness and arterial stiffness are emerging as markers of arterial aging and may serve as risk markers for VCI. Currently, no specific treatments for VCI have been approved by the US Food and Drug Administration. However, detection and control of the traditional risk factors for stroke and cardiovascular disease may be effective in the prevention of VCI, even in older people.

CONCLUSIONS

Vascular contributions to cognitive impairment and dementia are important. Understanding of VCI has evolved substantially in recent years, based on preclinical, neuropathologic, neuroimaging, physiological, and epidemiological studies. Transdisciplinary, translational, and transactional approaches are recommended to further our understanding of this entity and to better characterize its neuropsychological profile. There is a need for prospective, quantitative, clinical-pathological-neuroimaging studies to improve knowledge of the pathological basis of neuroimaging change and the complex interplay between vascular and Alzheimer disease pathologies in the evolution of clinical VCI and Alzheimer disease. Long-term vascular risk marker interventional studies beginning as early as midlife may be required to prevent or postpone the onset of VCI and Alzheimer disease. Studies of intensive reduction of vascular risk factors in high-risk groups are another important avenue of research.

Morphology parameters for intracranial aneurysm rupture risk assessment

OBJECTIVE

The aim of this study is to identify image-based morphological parameters that correlate with human intracranial aneurysm (IA) rupture.

METHODS

For 45 patients with terminal or sidewall saccular IAs (25 unruptured, 20 ruptured), three-dimensional geometries were evaluated for a range of morphological parameters. In addition to five previously studied parameters (aspect ratio, aneurysm size, ellipticity index, nonsphericity index, and undulation index), we defined three novel parameters incorporating the parent vessel geometry (vessel angle, aneurysm [inclination] angle, and [aneurysm-to-vessel] size ratio) and explored their correlation with aneurysm rupture. Parameters were analyzed with a two-tailed independent Student's t test for significance; significant parameters (P < 0.05) were further examined by multivariate logistic regression analysis. Additionally, receiver operating characteristic analyses were performed on each parameter.

RESULTS

Statistically significant differences were found between mean values in ruptured and unruptured groups for size ratio, undulation index, nonsphericity index, ellipticity index, aneurysm angle, and aspect ratio. Logistic regression analysis further revealed that size ratio (odds ratio, 1.41; 95% confidence interval, 1.03-1.92) and undulation index (odds ratio, 1.51; 95% confidence interval, 1.08-2.11) had the strongest independent correlation with ruptured IA. From the receiver operating characteristic analysis, size ratio and aneurysm angle had the highest area under the curve values of 0.83 and 0.85, respectively.

CONCLUSION

Size ratio and aneurysm angle are promising new morphological metrics for IA rupture risk assessment. Because these parameters account for vessel geometry, they may bridge the gap between morphological studies and more qualitative location-based studies.

Prospective evaluation of surgical microscope—integrated intraoperative near-infrared indocyanine green videoangiography during aneurysm surgery

Object. The authors prospectively compared a new technique of surgical microscope-based indocyanine green (ICG) videoangiography with intraoperative or postoperative digital subtraction (DS) angiography.

Method. The technique was performed during 187 surgical procedures in which 124 aneurysms in 114 patients were clipped. Using a newly developed setup, the ICG technique has been integrated into an operating microscope (Carl Zeiss Co., Oberkochen, Germany). A microscope-integrated light source containing infrared excitation light illuminates the operating field. The dye is injected intravenously into the patient, and intravascular fluorescence from within the blood vessels is imaged using a video camera attached to the microscope. The patency of parent, branching, and perforating arteries and documentation of clip occlusion of the aneurysm as shown by ICG videoangiography were compared with intraoperative or postoperative findings on DS angiography.

The results of ICG videoangiography corresponded with intra- or postoperative DS angiography in 90% of cases. The ICG technique missed mild but hemodynamically irrelevant stenosis that was evident on DS angiography in 7.3% of cases. The ICG technique missed angiographically relevant findings in three cases (one hemodynamically relevant stenosis and two residual aneurysm necks [2.7% of cases]). In two cases the missed findings were clinically and surgically inconsequential; in the third case, a 4-mm residual neck may require a second procedure. Indocyanine green videoangiography provided significant information for the surgeon in 9% of cases, most of which led to clip correction.

Conclusions. Microscope-based ICG videoangiography is simple and provides real-time information about the patency of vessels of all sizes and about the aneurysm sac. This technique may be useful during routine aneurysm surgery as an independent form of angiography or as an adjunct to intra- or postoperative DS angiography.

Regional leptomeningeal score on CT angiography predicts clinical and imaging outcomes in patients with acute anterior circulation occlusions

BACKGROUND AND PURPOSE

The regional leptomeningeal score is a strong and reliable imaging predictor of good clinical outcomes in acute anterior circulation ischemic strokes and can therefore be used for imaging based patient selection. Efforts to determine biological determinants of collateral status are needed if techniques to alter collateral behavior and extend time windows are to succeed.

MATERIALS AND METHODS

This was a retrospective Institutional Review Board-approved study of patients with acute ischemic stroke and M1 middle cerebral artery+/- intracranial internal carotid artery occlusion at our center from 2003 to 2009. The rLMC score is based on scoring pial and lenticulostriate arteries (0, no; 1, less; 2, equal or more prominent compared with matching region in opposite hemisphere) in 6 ASPECTS regions (M1-6) plus anterior cerebral artery region and basal ganglia. Pial arteries in the Sylvian sulcus are scored 0, 2, or 4. Good clinical outcome was defined as mRS ≤ 2 at 90 days.

RESULTS

The analysis included 138 patients: 37.6% had a good (17-20), 40.5% a medium (11-16), and 21.7% a poor (0-10) rLMC score. Interrater reliability was high, with an intraclass correlation coefficient of 0.87 (95% CI, 0.77%-0.95%). On univariate analysis, no single vascular risk factor was associated with the presence of poor rLMCs (P ≥ .20 for all comparisons). In multivariable analysis, the rLMC score (good versus poor: OR, 16.7; 95% CI, 2.9%-97.4%; medium versus poor: OR, 9.2, 95% CI, 1.7%-50.6%), age (< 80 years), baseline ASPECTS (≥ 8), and clot burden score (≥ 8) were independent predictors of good clinical outcome.

CONCLUSIONS

The rLMC score is a strong imaging parameter on CT angiography for predicting clinical outcomes in patients with acute ischemic strokes.

The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Trial

BACKGROUND

Transcranial Doppler ultrasound (TCD) and magnetic resonance angiography (MRA) can identify intracranial atherosclerosis but have not been rigorously validated against the gold standard, catheter angiography. The WASID trial (Warfarin Aspirin Symptomatic Intracranial Disease) required performance of angiography to verify the presence of intracranial stenosis, allowing for prospective evaluation of TCD and MRA. The aims of Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial were to define abnormalities on TCD/MRA to see how well they identify 50 to 99% intracranial stenosis of large proximal arteries on catheter angiography.

STUDY DESIGN

SONIA standardized the performance and interpretation of TCD, MRA, and angiography. Study-wide cutpoints defining positive TCD/MRA were used. Hard copy TCD/MRA were centrally read, blind to the results of angiography.

RESULTS

SONIA enrolled 407 patients at 46 sites in the United States. For prospectively tested noninvasive test cutpoints, positive predictive values (PPVs) and negative predictive values (NPVs) were TCD, PPV 36% (95% CI: 27 to 46); NPV, 86% (95% CI: 81 to 89); MRA, PPV 59% (95% CI: 54 to 65); NPV, 91% (95% CI: 89 to 93). For cutpoints modified to maximize PPV, they were TCD, PPV 50% (95% CI: 36 to 64), NPV 85% (95% CI: 81 to 88); MRA PPV 66% (95% CI: 58 to 73), NPV 87% (95% CI: 85 to 89). For each test, a characteristic performance curve showing how the predictive values vary with a changing test cutpoint was obtained.

CONCLUSIONS

Both transcranial Doppler ultrasound and magnetic resonance angiography noninvasively identify 50 to 99% intracranial large vessel stenoses with substantial negative predictive value. The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis trial methods allow transcranial Doppler ultrasound and magnetic resonance angiography to reliably exclude the presence of intracranial stenosis. Abnormal findings on transcranial Doppler ultrasound or magnetic resonance angiography require a confirmatory test such as angiography to reliably identify stenosis.

Early Recanalization After Intravenous Administration of Recombinant Tissue Plasminogen Activator as Assessed by Pre- and Post-Thrombolytic Angiography in Acute Ischemic Stroke Patients

BACKGROUND AND PURPOSE

Recanalization rates after the intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment have been poorly studied in acute stroke.

METHODS

CT angiography was performed before IV rt-PA in all patients and digital subtraction angiography was undertaken for intra-arterial thrombolysis in cases of no improvement after rt-PA infusion.

RESULTS

Forty-five patients were treated with IV rt-PA. Initial CT angiography showed relevant arterial occlusions in 35 patients. Recanalization after rt-PA therapy was demonstrated by digital subtraction angiography in 7 of the 31 patients with the occlusion on initial CT angiography: 2/16 in the internal carotid or proximal middle cerebral artery, 3/11 in the distal middle cerebral artery and 2/4 in the basilar artery occlusion.

CONCLUSIONS

The early recanalization rate after IV rt-PA use was very low in cases with large proximal arterial occlusions. CT angiography before IV rt-PA may be useful for the prediction of its efficacy.

Microneurosurgical management of middle cerebral artery bifurcation aneurysms

BACKGROUND

Of the MCA aneurysms, those located at the main bifurcation of the MCA (MbifA) are by far the most frequent. The purpose of this article is to review the practical anatomy, preoperative planning, and avoidance of complications in the microsurgical dissection and clipping of MbifAs.

METHODS

This review, and the whole series on intracranial aneurysms, is mainly based on the personal microneurosurgical experience of the senior author (JH) in 2 Finnish centers (Helsinki and Kuopio), which serve without patient selection the catchment area in southern and eastern Finland.

RESULTS

These 2 centers have treated more than 10,000 patients with intracranial aneurysm's since 1951. In the Kuopio Cerebral Aneurysm Data Base of 3005 patients with 4253 aneurysms, MbifAs formed 30% of all ruptured aneurysms, 36% of all unruptured aneurysms, 35% of all giant aneurysms, and 89% of all MCA aneurysms. Importantly, in 45%, rupture of MbifA caused an ICH.

CONCLUSIONS

Middle cerebral artery bifurcation aneurysms are often broad necked and may involve one or both branches of the bifurcation (M2s). The anatomical and hemodynamic features of MbifAs make them usually more favorable for microneurosurgical treatment. In population-based services, MbifAs are frequent targets of elective surgery (unruptured), acute surgery (ruptured), and emergency surgery (large ICH), even advanced approaches (giant). The challenge is to clip the neck adequately, without neck remnants, while preserving the bifurcational flow.

Validation of transcranial Doppler with computed tomography angiography in acute cerebral ischemia

BACKGROUND AND PURPOSE

Both transcranial Doppler (TCD) and spiral computed tomography angiography (CTA) are used for noninvasive vascular assessment tools in acute stroke. We aimed to evaluate the diagnostic accuracy of TCD against CTA in patients with acute cerebral ischemia.

METHODS

Consecutive patients presenting to the Emergency Department with symptoms of acute (<24 hours) cerebral ischemia underwent emergent high-resolution brain CTA with a multidetector helical scanner. TCD was performed at bedside with a standardized, fast-track insonation protocol before or shortly (<2 hours) after completion of the CTA. Previously published diagnostic criteria were prospectively applied for TCD interpretation independent of angiographic findings.

RESULTS

A total of 132 patients (74 men, mean+/-SD age 63+/-15 years) underwent emergent neurovascular assessment with brain CTA and TCD. Compared with CTA, TCD showed 34 true-positive, 9 false-negative, 5 false-positive, and 84 true-negative studies (sensitivity 79.1%, specificity 94.3%, positive predictive value 87.2%, negative predictive value 90.3%, and accuracy 89.4%). In 9 cases (7%), TCD showed findings complementary to the CTA (real-time embolization, collateralization of flow with extracranial internal carotid artery disease, alternating flow signals indicative of steal phenomenon).

CONCLUSIONS

Bedside TCD examination yields satisfactory agreement with urgent brain CTA in the evaluation of patients with acute cerebral ischemia. TCD can provide real-time flow findings that are complementary to information provided by CTA.

Three-dimensional computerized tomography angiography—guided surgery of acutely ruptured cerebral anuerysms

Object. The aim of this study was to assess whether aneurysm surgery can be performed in patients with ruptured cerebral aneurysms by using three-dimensional computerized tomography (3D-CT) angiography alone, without conventional catheter angiography.

Methods. In a previous study, 60 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms were prospectively evaluated using both 3D-CT and conventional angiography, which resulted in a 100% accuracy for 3D-CT angiography in the diagnosis of ruptured aneurysms, and a 96% accuracy in the identification of associated unruptured aneurysms. The results led the authors to consider replacing conventional angiography with 3D-CT angiography for use in diagnosing ruptured aneurysms, and to perform surgery aided by 3D-CT angiography alone without conventional angiography. Based on the results, 100 consecutive patients with SAH who had undergone surgery in the acute stage based on 3D-CT angiography findings have been studied since December 1996. One hundred ruptured aneurysms, including 41 associated unruptured lesions, were detected using 3D-CT angiography. In seven of 100 ruptured aneurysms, which included four dissecting vertebral artery aneurysms, two basilar artery (BA) tip aneurysms, and one BA—superior cerebellar artery aneurysm, 3D-CT angiography was followed by conventional angiography to acquire diagnostic confirmation or information about the vein of Labbé, which was needed to guide the surgical approach for BA tip aneurysms. All of the ruptured aneurysms were confirmed at surgery and treated successfully. Ninety-three patients who underwent operation with the aid of 3D-CT angiography only had no complications related to the lack of information gathered by conventional angiography. The 3D-CT angiography studies provided the authors with the aneurysm location as well as surgically important information on the configuration of its sac and neck, the presence of calcification in the aneurysm wall, and its relationship to the adjacent vessels and bone structures.

Conclusions The authors believe that 3D-CT angiography can replace conventional angiography in the diagnosis of ruptured aneurysms and that surgery can be performed in almost all acutely ruptured aneurysms by using only 3D-CT angiography without conventional angiography.

Diagnostic accuracy of CT angiography and CT perfusion for cerebral vasospasm: a meta-analysis

BACKGROUND AND PURPOSE

In recent years, the role of CTA and CTP for vasospasm diagnosis in the setting of ASAH has been the subject of many research studies. The purpose of this study was to perform a meta-analysis of the diagnostic performance of CTA and CTP for vasospasm in patients with ASAH by using DSA as the criterion standard.

MATERIALS AND METHODS

The search strategy for research studies was based on the Cochrane Handbook for Systematic Reviews, including literature data bases (PubMed, Embase, Cochrane Database of Systematic Reviews, and the Web of Science) and reference lists of manuscripts published from January 1996 to February 2009. The inclusion criteria were the following: 1) published manuscripts, 2) original research studies with prospective or retrospective data, 3) patients with ASAH, 4) CTA or CTP as the index test, and 5) DSA as the reference standard. Three reviewers independently assessed the quality of these research studies by using the QUADAS tool. Pooled estimates of sensitivity, specificity, LR+, LR-, DOR, and the SROC curve were determined.

RESULTS

CTA and CTP searches yielded 505 and 214 manuscripts, respectively. Ten research studies met inclusion criteria for each CTA and CTP search. Six CTA and 3 CTP studies had sufficient data for statistical analysis. CTA pooled estimates had 79.6% sensitivity (95%CI, 74.9%-83.8%), 93.1%specificity (95%CI, 91.7%-94.3%), 18.1 LR+ (95%CI, 7.3-45.0), and 0.2 LR- (95%CI, 0.1-0.4); and CTP pooled estimates had 74.1% sensitivity (95%CI, 58.7%- 86.2%), 93.0% specificity (95% CI, 79.6%-98.7%), 9.3 LR+ (95%CI, 3.4-25.9), and 0.2 LR- (95%CI, 0.04-1.2). Overall DORs were 124.5 (95%CI, 28.4-546.4) for CTA and 43.0 (95%CI, 6.5-287.1) for CTP. Area under the SROC curve was 98 ± 2.0%for CTA and 97 ± 3.0% for CTP.

CONCLUSIONS

The high diagnostic accuracy determined for both CTA and CTP in this meta-analysis suggests that they are potentially valuable techniques for vasospasm diagnosis in ASAH. Awareness of these results may impact patient care by providing supportive evidence for more effective use of CTA and CTP imaging in ASAH.

Spontaneous subarachnoid haemorrhage with negative initial angiography: A review of 143 cases

The need for repeat angiography in patients with subarachnoid haemorrhage (SAH) who initially present with a negative angiogram is still debated. The aim of this study was to provide a management protocol for 'angiogram-negative SAH'. From January 1986 to June 2004, 143 patients with SAH were admitted to our institution with negative initial angiograms. We classified the 143 patients into three groups: group I, with no SAH on CT scan, but confirmed by cerebrospinal fluid analysis; group II, with a perimesencephalic pattern of SAH; and group III, with a non-perimesencephalic pattern of SAH. Out of the 143 patients, 103 underwent repeat angiography, and 18 were found to have ruptured aneurysms that were not detected on the initial angiogram (false negative rate: 17.5% overall, 0% in group I, 1.5% in group II, and 45.9% in group III). Repeat angiography should be performed, particularly in patients who have a non-perimesencephalic SAH pattern, for detection of initially unrecognised ruptured aneurysms.

Inaccuracy of angiography in the diagnosis of carotid ulceration

It is generally stated that ulceration of the carotid bifurcation plaque may give rise to embolization and symptoms of cerebral ischemia. It has been suggested that prophylactic carotid endarterectomy is indicated in asymptomatic patients if the angiogram is interpreted as showing ulceration. We therefore determined the accuracy of the radiologic diagnosis of ulceration by comparing the radiologic and morphologic findings in 155 carotid endarterectomies. Ulceration was diagnosed in 54% of the angiograms and 47% of the surgical specimens and was not related to the degree of stenosis. Angiography had a sensitivity of 73%, a specificity of 62% and an overall accuracy of 67%. For the non-flow-restrictive lesions these figures were 65%, 66%, and 66%. If surgery were based on the angiographic diagnosis of ulceration in plaques with less than 50% stenosis, 16 out of 42 operations (38%) would have been done unnecessarily. Variability of the angiographic diagnosis of ulceration is also shown by a high interobserver variability; two sets of two authors read the angiograms independently and disagreed in 24% of the cases. The decision to operate should not depend entirely upon the angiographic diagnosis of ulceration.

Cortical perfusion measurement by indocyanine-green videoangiography in patients undergoing hemicraniectomy for malignant stroke

BACKGROUND AND PURPOSE

Assessment of cerebral perfusion during neurosurgical procedures would be beneficial to identify areas at risk and to guide placement of monitoring probes. Therefore, we have adapted near-infrared indocyanine-green (ICG) videoangiography to assess cortical perfusion intraoperatively.

METHODS

ICG videoangiography was performed intraoperatively in 6 patients after decompressive hemicraniectomy for middle cerebral artery stroke. Flow maps of cortical perfusion were generated with IC-CALC 1.1 software by calculating the ratio of difference in fluorescence intensity and rise time.

RESULTS

Excellent visualization of cerebral arteries, cortical perfusion and collateral circulation via leptomeningeal anastomoses could be demonstrated in all cases. Flow maps revealed high spatial resolution and showed heterogeneous maple-leaf-shaped hypoperfusion. 26.5+/-13.7% and 29.0+/-9.1% of the exposed cortical surface (141+/-18 cm2) demonstrated core and penumbral flow, respectively.

CONCLUSIONS

ICG videoangiography appears to be a valuable tool to precisely detect relative cortical tissue perfusion. Thus, it may provide useful research data on the pathophysiology of human stroke, help surgeons to maintain adequate brain perfusion intraoperatively, and simplify adequate placement of tissue probes to monitor critically hypoperfused brain tissue.

Measurement variability of carotid atherosclerosis: real-time (B-mode) ultrasonography and angiography

To quantify the within- and between-reader agreement of carotid B-mode ultrasonography and angiography interpretation, images from 117 patients examined by both modalities were read multiple times. Angiographic measurements were more reproducible than those of B-mode scans for all parameters except lesion width, but variations for B-mode scan measurements were similar to those for angiographic measurements. Within-reader agreement on the presence of ulceration was substantial for both modalities, whereas between-reader agreement was poor for B-mode scan and only moderate for angiography.

Comparison of the ECST, CC, and NASCET grading methods and ultrasound for assessing carotid stenosis. European Carotid Surgery Trial. North American Symptomatic Carotid Endarterectomy Trial

We compared three angiographic methods for grading of carotid stenosis and examined the correlation between angiographic and ultrasound findings. Two observers independently measured 111 carotid stenoses on arteriographic films of 84 patients. The stenoses were graded according to the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Common Carotid (CC) methods. The results obtained by these methods were compared, and the interobserver reproducibility of the measurements was calculated. In addition, all angiographic results were compared to ultrasound findings obtained before angiography. Measurements using the CC method were the most reproducible and those using the NASCET method the least. The NASCET method underestimated the degree of stenosis compared to the other methods. The ECST and CC methods yielded almost identical results (97% agreement). Ultrasound provided an accuracy of 94% compared to ECST and CC methods and 84% compared to the NASCET method. Interobserver reproducibility of angiographic quantification of carotid stenoses was best for the CC and ECST methods and least for the NASCET method. Ultrasound demonstrated better accuracy than the ECST and CC methods.

Conventional cerebral angiography in children with ischemic stroke

A retrospective review of conventional cerebral angiograms of 46 children with ischemic stroke was undertaken. Comparison was made with findings on magnetic resonance imaging and magnetic resonance angiography where available. Thirty-six children (78%) underwent magnetic resonance angiography in addition to conventional cerebral angiography. Seven patients had normal cerebral angiograms. Magnetic resonance angiography was diagnostic in 25 of 28 patients with large vessel occlusion, stenosis, or moya-moya syndrome. Conventional angiography was abnormal in four of nine patients with a normal magnetic resonance angiography. All patients with normal conventional angiograms also had normal magnetic resonance angiograms. Conventional angiography, either diagnostic or yielding further information, altered management in five patients with arterial dissection, one patient with large vessel occlusion, one patient with large vessel stenosis, and four patients with arteritis. On the basis of this experience, a clinical algorithm for the use of conventional cerebral angiography in the investigation of ischemic stroke in children is proposed.

Results of four technical investigations in fifty clinically brain dead patients

Fifty consecutive patients (aged 19-77 years, median 56 years) with primary cerebral diseases and the clinical signs of absent cortical and brainstem function were subjected to electroencephalography (EEG), brainstem acoustic evoked potentials (BAEP), extracranial Doppler ultrasonography (ECD) and arterial digital subtraction angiography (DSA). In the majority of cases the results of the technical tests agreed with the clinical signs and were suggestive of brain death. However, in one patient EEG revealed clear bioelectrical activity. In 6 cases, doubts existed about whether the EEG was isoelectric; in 3 of the 6 cases biological activity might have been present. In 31 of 42 patients ECD showed a typical pattern of intracranial circulatory arrest, in 9 of 42 ECD revealed a pattern suggestive of the cessation of cerebral blood flow. In four patients BAEP recordings compatible with brain death were recorded 2-3 days before intracranial circulatory arrest. In 2 patients with isoelectric EEG and absent BAEP arterial DSA demonstrated residual perfusion. The findings are discussed in view of the conceptional differences concerning brain death. It is concluded that the strict application of the concept of death of the whole brain requires angiographic demonstration of absent intracerebral blood flow.

Comparison of color-flow Doppler scanning, power Doppler scanning, and frequency shift for assessment of carotid artery stenosis

OBJECTIVE

We investigated the accuracy of color-flow Doppler (CD) scanning, power Doppler (PD) scanning, and peak systolic Doppler frequency shift (PSF) in assessment of carotid artery stenosis with angiography used as gold standard, including the measurement techniques used in the North American Symptomatic Carotid Surgery Trial (NASCET) and the European Carotid Surgery Trial (ECST).

METHODS

Fifty-eight consecutive patients diagnosed for carotid artery surgery underwent color-coded duplex sonography and angiography. The duplex examination included the assessment of PSF and the videotaping of sagittal images in CD and PD mode from the proximal common carotid artery to the distal internal carotid artery. Two experienced examiners performed the studies, but once one examiner had done the taping, the other examiner was allowed only to review the tape. Separately, each examiner reviewed the tapes and determined by cursor settings each stenosis according to NASCET and ECST. For interobserver agreement kappa statistic was used. To compare with angiography (degree of stenosis 40%, 50%, 60%, 70%, and 80%) sensitivity, specificity, positive and negative predictive values, and overall accuracy were calculated. PSF cut-off frequencies were based on receiver operator curve analysis.

RESULTS

Because interobserver agreement in CD and PD was good (chance-corrected kappa > 0.6), further analysis used the between-observer mean value for each stenosis. With the NASCET measurement technique, accuracy of Doppler techniques to distinguish a 50% stenosis was 89% for PSF, 91% for CD, and 93% for PD; for a 70% stenosis it was 83% for PSF, 84% for CD, and 81% for PD. With the ECST measurement technique, accuracy to distinguish a 70% stenosis was 86% for PSF, 88% for CD, and 86% for PD; for an 80% stenosis it was 87% for PSF, 87% for CD, and 77% for PD.

CONCLUSION

CD and PD carotid artery stenosis measurements are highly reproducible, and in our hands provided accuracy equal to PSF.

3-Dimensional computed tomographic angiography for use of surgery planning in patients with intracranial aneurysms

BACKGROUND

After subarachnoid haemorrhage (SAH) diagnostic evaluation of the underlying cause is warranted since the rebleeding rate is high. The objective of the study was to answer the question, whether 3-Dimensional computed tomographic angiography (3D-CTA) is able to accurately determine the surgical indications in patients with intracranial aneurysms.

METHODS

After performing 3D-CTA the size of the aneurysm, direction of the aneurysmal dome, neck position and variants of the circle of Willis were analysed. Surgery was performed solely on CTA data in those cases, where the aneurysm was clearly visible. If the findings were negative or inconclusive, intra-arterial digital subtraction angiography (DSA) was also done.

FINDINGS

Between January 2001 and December 2002 100 patients (68 F, 32 M) were examined and 123 aneurysms (86 ruptured and 37 unruptured) were diagnosed. All patients received CTA preoperatively and in 27 patients selective DSA was additionally performed. Postoperatively in 34 patients the operative result was checked by DSA. A good correlation between CTA and the intra-operative findings was present in 92 of 100 patients. One aneurysm was not seen on CTA, but was on DSA. In four cases we could confirm DSA findings in CTA after re-evaluation of the data. In three cases neither CTA nor DSA clearly showed an aneurysm, but it was confirmed during surgery. A good correlation between CTA and DSA was found in 60 of 61 patients (98%). The correlation between CTA and intra-operative findings was good as expected in 92 patients, in 5 patients an aneurysm was detected on re-evaluation. Only one aneurysm could not be demonstrated by CTA but in DSA.

CONCLUSION

CTA is less invasive, less time consuming, cheaper and easier to demonstrate the essential information regarding the aneurysm than DSA. We therefore recommend that following a careful analysis most aneurysms - 92% - can be operated solely on CTA data.

Multicenter validation study of real-time ultrasonography, arteriography, and pathology: pathologic evaluation of carotid endarterectomy specimens

The morphologic description and measurements of endarterectomy specimens are usually believed to be accurate and are used as the gold standard against which the findings of diagnostic procedures are judged. Pathology data on 289 endarterectomy specimens from five participating centers and the corresponding angiography and B-mode ultrasonography data provided a basis for scrutinizing the validity of using the morphologic measurements as a standard. Discrepancies of greater than 1 mm between pathology and angiography measurements of minimum residual lumen occurred in 35% of the cases and between pathology and B-mode ultrasonography measurements in 64% of the cases. Discrepancies of greater than 1 mm between pathology- and angiography-measured lesion width occurred in 81% of the cases and between pathology and B-mode ultrasonography measurements in 64% of the cases. The cases representing mismatches of greater than 1 mm at one participating center were subjected to a rigorous review, with remeasurement of all morphologic features, in an attempt to explain the discrepancies. Various types of artifactual distortion of the specimens, the presence of slit-like and occluded lumens that were likely related to loss of perfusion pressure, and an inability to match planes of interrogation used in angiography and B-mode ultrasonography with pathology planes contributed significantly to the existence of mismatches. On the other hand, fixation and decalcification produced minimal and insignificant distortional changes. We conclude that the acquisition of quantitative data from endarterectomy specimens and the acceptance of morphologic data as a standard are limited by a number of problems that can be defined but have been difficult to resolve.

Recurrence of cerebral arteriovenous malformations in children: Report of two cases and review of the literature

BACKGROUND

Angiography is considered the standard to assess the treatment success of cerebral arteriovenous malformations (AVMs). When postoperative angiograms show neither residual nidus nor early draining veins, patients are considered cured, and the risks of hemorrhage are eliminated. However, this notion is challenged by the development of recurrent AVMs in children. In our report, 2 children developed recurrent AVMs after undergoing complete resection, which was documented by postoperative angiography. We review other similar cases reported in the literature to help establish guidelines for postoperative monitoring.

METHODS

In this retrospective review, 36 children underwent complete surgical resection of cerebral AVMs that were documented by intra- or postoperative angiography. After a follow-up period ranging from 1 to 17 years, rates of recurrence were assessed.

RESULTS

Although angiographic documentation showed complete resection, 2 children developed recurrences 3 and 5 years later. Among these 36 children, the recurrence rate was 5.5% at follow-up (mean 9 years).

CONCLUSIONS

Based on our data and review of the literature, intra- or early postoperative angiography is essential to exclude the presence of a residual nidus but does not ensure cure of the AVMs in children. If postoperative angiographic scans are obtained too early, postoperative changes may prevent the detection of a residual nidus. Therefore, we recommend that angiographic scans be obtained intraoperatively or early postoperatively to document complete resection and again at 1 and 5 years after surgical resection.

Brain Computed Tomography Angiographic Scans as the Sole Diagnostic Examination for Excluding Aneurysms in Patients with Perimesencephalic Subarachnoid Hemorrhage

OBJECTIVE

In an era in which new computed tomographic scanners approach 100% sensitivity for finding intracranial aneurysms in patients with a perimesencephalic subarachnoid hemorrhage (SAH) pattern, digital subtraction angiography (DSA) is still considered the gold standard. Our purpose was to investigate whether or not computed tomography angiographic (CTA) scanning can be used as the sole diagnostic tool in this setting, and thus replace DSA.

METHODS

Two hundred fifty patients with atraumatic SAH presented to our institute between November 2001 and November 2005. We performed a retrospective search for those patients who had a negative brain CTA scan for aneurysms. Of these, those with a computed tomographic scan showing perimesencephalic SAH at admission were selected, and only those who had DSA performed were included.

RESULTS

We found 30 patients with negative brain CTA scans that matched the perimesencephalic SAH pattern and had DSA performed. The mean time for performing a brain CTA scan was 3.8 +/- 4.4 days, and for DSA 11 +/- 12 days, after the initiation of symptomatology. The interval between CTA and DSA was 5.9 +/- 15 days. There were two patients in whom CTA was considered negative but still suspicious for having an aneurysm; DSA was negative for both.

CONCLUSION

Brain CTA scanning alone is a good and conclusive diagnostic tool to rule out aneurysms in patients presenting with the classic perimesencephalic SAH pattern and thus can replace DSA and its corresponding risks. The latter can be reserved for those patients in whom CTA is doubtful.