Detection of delayed cerebral vasospasm, after rupture of intracranial aneurysms, by magnetic resonance angiography

Advances in biomarkers for vasospasm - Towards a future blood-based diagnostic test

Objective

Cerebral vasospasm and the resultant delayed cerebral infarction is a significant source of mortality following aneurysmal SAH. Vasospasm is currently detected using invasive or expensive imaging at regular intervals in patients following SAH, thus posing a risk of complications following the procedure and financial burden on these patients. Currently, there is no blood-based test to detect vasospasm.

Methods

PubMed, Web of Science, and Embase databases were systematically searched to retrieve studies related to cerebral vasospasm, aneurysm rupture, and biomarkers. The study search dated from 1997 to 2022. Data from eligible studies was extracted and then summarized.

Results

Out of the 632 citations screened, only 217 abstracts were selected for further review. Out of those, only 59 full text articles met eligibility and another 13 were excluded.

Conclusions

We summarize the current literature on the mechanism of cerebral vasospasm and delayed cerebral ischemia, specifically studies relating to inflammation, and provide a rationale and commentary on a hypothetical future bloodbased test to detect vasospasm. Efforts should be focused on clinical-translational approaches to create such a test to improve treatment timing and prediction of vasospasm to reduce the incidence of delayed cerebral infarction.

Cerebral Vasospasm After Burr Hole Evacuation of Chronic Subdural Hematoma

Cerebral vasospasm is a frequent complication of subarachnoid hemorrhage. We report a case of chronic subdural hematoma complicated by cerebral vasospasm after burr hole evacuation. A 74-year-old woman underwent burr hole evacuation of a chronic subdural hematoma. She developed left hemiparesis and disturbance of consciousness on postoperative day 3. Magnetic resonance imaging showed a right parietal infarct and decreased cerebral blood flow signal in the right middle cerebral artery territory. Digital subtraction angiography showed multiple segmental narrowings of the right middle cerebral artery. Her neurological symptoms recovered with conservative treatment. Follow-up angiography showed improvement in the arterial narrowing, which finally led to a diagnosis of cerebral vasospasm. Cerebral vasospasm can occur after burr hole evacuation of chronic subdural hematoma. Magnetic resonance angiography is useful for determining the cause of postoperative neurological worsening in chronic subdural hematoma patients.

Transcranial Doppler ultrasound: Clinical applications from neurological to cardiological setting

Transcranial Doppler (TCD) ultrasonography is a rapid, noninvasive, real-time, and low-cost imaging technique. It is performed with a low-frequency (2 MHz) probe in order to evaluate the cerebral blood flow (CBF) and its pathological alterations, through specific acoustic windows. In the recent years, TCD use has been expanded across many clinical settings. Actually, the most widespread indication for TCD exam is represented by the diagnosis of paradoxical embolism, due to patent foramen ovale, in young patients with cryptogenic stroke. In addition, TCD has also found useful applications in neurological care setting, including the following: cerebral vasospasm following acute subarachnoid hemorrhage, brain trauma, cerebrovascular atherosclerosis, and evaluation of CBF and cerebral autoregulation after an ischemic stroke event. The present review aimed to describe the most recent evidences of TCD utilization from neurological to cardiological setting.

Intracranial stenting as a bail-out option for posthemorrhagic cerebral vasospasm: a single-center experience with long-term follow-up

Background

Cerebral vasospasm (CVS) is a leading cause of morbidity and mortality in patients after aneurysmal subarachnoid hemorrhage (aSAH). Endovascular treatment, including intraarterial infusion of drugs with vasodilation effects, and balloon- and stentriever angioplasty, are helpful but may achieve only short-term effects. There is a clinical need for long-lasting treatment of refractory recurrent vasospasm. We report our experience in stent implantation as a treatment for recurrent severe post-SAH vasospasm.

Methods

A retrospective analysis of our institutional database of 883 patients with SAH, managed between January 2010 and December 2021, was performed. Six patients were identified as having received intracranial stenting in the context of post-SAH cerebral vasospasm. All patients were initially treated with intra-arterial infusion of nimodipine and/or milrinone. Self-expanding intracranial stents were implanted during endovascular aneurysm treatment to enable access despite impaired perfusion (Group 1) or as a bail-out strategy after failed intraarterial drug infusion or mechanical treatment (Group 2). All stented patients received dual antiplatelet therapy (DAPT) for 6 months.

Results

Nine vessels in six patients with severe post-SAH vasospasm were stented. The stents were deployed in 16 vessel segments. All attempted implantations were technically successful. All patients demonstrated radiographic and clinical improvement of the vessel narrowing. No recurrent vasospasm or permanent vessel occlusion of the stented vessels was encountered. A thrombus formation in a Group 1 patient resolved under 4 mg eptifibatide IA infusion. During long-term angiographic follow-up, neither in-stent stenosis nor stent occlusion was found.

Conclusions

Endovascular implantation of self-expanding stents is a potential ultima ratio strategy for patients with severe refractory post-SAH cerebral vasospasm. Stents with reduced thrombogenicity (avoiding DAPT) and bioabsorbable self-expanding stents might further advance this concept.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02862-4.

Vasospasm-Related Death after Aneurysmal Subarachnoid Hemorrhage: A Retrospective Case-Control Study

BACKGROUND

Vasospasm after the rupture of an intracranial aneurysm is a frequent phenomenon and is the main cause of morbidity and mortality in patients who have survived intracranial hemorrhage and aneurysm treatment. We analyzed the diagnosis and management of patients with aneurysmal subarachnoid hemorrhage who eventually died from ischemic brain damage due to vasospasm.

METHODS

Between January 2007 and December 2021 (15 years), a total of 1064 patients were diagnosed with an aneurysmal intracranial hemorrhage in a single comprehensive neurovascular center. Vasospasm was diagnosed in 408 patients (38.4%). A total of 187 patients (17.6%) died within 90 days of the aneurysm rupture. In 64 of these 187 patients (33.7%), vasospasm was considered to be the cause of death. In a retrospective analysis, demographic and clinical data for patients without, with non-fatal, and with fatal vasospasm were compared. The patients with fatal vasospasm were categorized into the following subgroups: "no diagnosis and treatment" (Group a), "delayed diagnosis" (Group b), "cardiovascular complications" (Group c), and "vasospasm-treatment complications" (Group d).

RESULTS

Among the patients with fatal vasospasm, 31 (48.4%) were assigned to group a, 26 (40.6%) to group b, seven (10.9%) to group c, and none (0%) to group d.

CONCLUSION

The early recognition of severe posthemorrhagic vasospasm is a prerequisite for any treatment and requires routine diagnostic imaging in all unconscious patients. Aggressive endovascular vasospasm treatment may fail to prevent death but is infrequently the cause of a fatal outcome.

Radiation Exposure in the Acute Phase after Aneurysmal Subarachnoid Hemorrhage in the Era of CT Perfusion

PURPOSE

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high risk of developing multiple complications requiring further diagnostics including imaging associated with radiation exposure (RE). Since aSAH often affects younger patients, the obtained cumulative RE may have serious long-term health consequences. The aim of this study was to calculate the cumulative RE in the acute phase after aSAH and to identify contributors to RE. Additionally, we investigated whether there is a correlation of RE with outcome.

METHODS

A retrospective analysis of patients with aSAH treated at our department from 2012 to 2018 was performed. The radiation dose of every single cranial radiological examination was calculated for every patient. The outcome was assessed according to the modified Rankin scale (mRS) 3 months after ictus. Factors associated with high RE were evaluated and the correlation of RE with outcome was assessed.

RESULTS

In 268 included consecutive patients, the mean cumulative RE per patient was 39.95 mSv, ranging from 2 to 265.5 mSv. A higher RE correlated with delayed cerebral ischemia (r = 0.52, p < 0.0001), delayed infarction (r = 0.25, p < 0.0001), delayed ischemic neurological deficits (r = 0.29, p < 0.0001) and transcranial Doppler (TCD)-vasospasm (r = 0.34, p < 0.0001). Independent predictors of outcome were age (p = 0.0001), World Federation of Neurosurgical Societies (WFNS) grade (p < 0.0001) and delayed infarction (p = 0.0004), while RE did not correlate with outcome.

CONCLUSION

There is a considerable imaging-related RE in aSAH patients. A meticulous decision-making process and imaging protocols with lower RE for the deployment of CT-based and fluoroscopy-based imaging is indicated in order to minimize the risk for radiation-mediated heath consequences in this patient population.

Evaluation of the Accuracy in Maximum Intensity Projection Images of Cerebral Computed Tomographic Angiography for the Diagnosis of Cerebral Vasospasm Following Subarachnoid Hemorrhage, in Comparison to Digital Subtraction Angiography

Objective

The purpose of this retrospective study is to determine the accuracy of maximum intensity projection (MIP) images of computed tomographic angiography (CTA) for diagnosis of cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH) compared with that of digital subtraction angiography (DSA).

Materials and Methods

For patients admitted to our hospital for SAH, MIP images of CTA and DSA were checked at admission, and images were taken again 1 week later. This protocol was used in 39 cases. MIP images of CTA and DSA examinations were reviewed by two independent readers.

Results

Accuracy of MIP images of CTA in various arterial segments, using DSA as the gold standard: the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for different segments varied from 84 to 97, 33–100, 84–100%, 25–85, and 79–97%, respectively, for readers. Accuracy of CTA in various vasospasm severity, using DSA as the gold standard: the sensitivity, specificity, PPV, NPV, and accuracy for different vasospasm severity varied from 44 to 100, 69–100, 36–100%, 61–100, and 88–100%, respectively, for readers. Accuracy of CTA in central segments versus peripheral segments, using DSA as the gold standard: the sensitivity, specificity, PPV, NPV, and accuracy for central segments and peripheral segments varied from 90 to 94, 68–83, 93–97%, 56–69, and 87–93%, respectively, for readers.

Conclusion

MIP imaging of CTA is a useful modality when diagnosing CV after SAH.

Three-dimensional spin-echo-based black-blood MRA in the detection of vasospasm following subarachnoid hemorrhage

BACKGROUND

Black-blood MR angiography (BBMRA), which utilizes a non-T₁ contrast spin-echo type technique, has been expected to overcome several issues associated with time-of-flight (TOF) MRA.

PURPOSE

To investigate the efficacy of BBMRA to detect vasospasms following subarachnoid hemorrhage (SAH).

STUDY TYPE

Retrospective.

SUBJECTS

Seventeen patients with SAH in their early posttreatment period.

FIELD STRENGTH/SEQUENCE

BBMRA, which uses a volumetric isotropic turbo spin-echo acquisition (VISTA), and TOF-MRA on 1.5T scanners.

ASSESSMENT

Visualization of supratentorial arteries and veins in BBMRA was rated on a 4-point scale by two neuroradiologists. Another neuroradiologist independently assessed TOF-MRA. The degree of the vasospasm was then evaluated using a 3-point scale by the same readers. The diagnostic performance of the MRAs was evaluated using computed tomography angiography (CTA) or digital subtraction angiography (DSA) as the standard of reference.

STATISTICAL TESTS

Wilcoxon signed rank test, McNemar test, and Cohen's kappa coefficient.

RESULTS

BBMRA provided superior visualization of the anterior and middle cerebral arteries than TOF-MRA (P < 0.05). The depiction of the veins was more pronounced on BBMRA (P < 0.01). Of the 166 arterial segments evaluated by CTA or DSA, 23 (13.9%) could not be assessed using TOF-MRA because of high signal hemorrhage, whereas BBMRA enabled visualization of all the segments. Vasospasm was confirmed in 30 segments by CTA or DSA. The sensitivity, specificity, and positive and negative predictive values were 73, 96, 76, and 95 for TOF-MRA and 91, 100, 100, and 98 for BBMRA, respectively (P = 0.13 for sensitivity, P = 0.06 for specificity). The agreement of the degree of vasospasm between MRA and the standard of reference, as indicated by kappa value, was 0.71 (95% confidence interval [CI], 0.55-0.87) for TOF-MRA and 0.91 (95% CI, 0.82-0.99) for BBMRA.

DATA CONCLUSION

BBMRA, owing to its contrast properties, may be superior to TOF-MRA for the evaluation of intracranial arteries after SAH.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:800-807.

Vasospasm Post Pituitary Surgery: Systematic Review and 3 Case Presentations

Background:

Vasospasm is a known complication of aneurysmal subarachnoid hemorrhage and is a major cause of neurological morbidity and mortality. It is infrequently associated with pituitary adenoma surgery. We report three cases and present a systematic review of the literature with a view towards guiding neurosurgeons in the prevention and management of this complication.

Results:

Including our experience, vasospasm complicating pituitary adenoma surgery has been documented in 29 patients (mean age of 45). All cases occurred in the setting of a postoperative hemorrhage: 21 had a subarachnoid hemorrhage and 10 had a postoperative hematoma requiring evacuation. Initial clinical appearance of delayed cerebral ischemia attributable to vasospasm occurred from postoperative Days 2-13 (most commonly Day 5). Digital subtraction angiography and medical management were the most common diagnostic and therapeutic strategies, respectively. Glasgow Outcome Scores were ≤3 in 59% of cases. Univariate logistic regression identified later diagnosis of vasospasm and surgery for hematoma evacuation to be independently associated with better outcomes.

Conclusion:

Vasospasm should be considered in the differential diagnosis of patients demonstrating altered mental or neurological status following pituitary surgery, particularly if there has been postoperative hemorrhage of any degree. Prompt treatment should be instituted to optimize outcome.

Improvement of the diagnostic accuracy of MRA with subtraction technique in cerebral vasospasm

PURPOSE

Vasospasm has been considered the most severe acute complication after subarachnoid hemorrhage (SAH). MRA is not considered ideal for detecting cerebral vasospasm because of background including the hemorrhage. The aim of this study is to evaluate the efficacy of Subtraction MRA (SMRA) by comparing it to that of conventional MRA (CMRA) for diagnosis of cerebral vasospasm.

METHODS

Arteries were assigned to one of three categories based on the degree of MRA diagnostic quality of vasospasm (quality score): 0, bad … 2, good. Furthermore each artery was assigned to one of four categories based on the degree of vasospasm severity (SV score): 0, no vasospasm … 3, severe. The value of the difference between DSA-SV score and MRA-SV score was defined as the DIF score. CMRA and SMRA were compared for each arterial region with regard to quality score and DIF score.

RESULTS

The average CMRA and SMRA quality score were 1.46 and 1.79; the difference was statistically significant. The average CMRA and SMRA DIF score were 1.08 and .60; the difference was statistically significant.

CONCLUSIONS

Diagnosis of cerebral vasospasm is more accurate by SMRA than by CMRA. The advantages are its noninvasive nature and its ability to detect cerebral vasospasm.

Inflammation, cerebral vasospasm, and evolving theories of delayed cerebral ischemia

Cerebral vasospasm (CVS) is a potentially lethal complication of aneurysmal subarachnoid hemorrhage (aSAH). Recently, the symptomatic presentation of CVS has been termed delayed cerebral ischemia (DCI), occurring as early as 3-4 days after the sentinel bleed. For the past 5-6 decades, scientific research has promulgated the theory that cerebral vasospasm plays a primary role in the pathology of DCI and subsequently delayed ischemic neurological decline (DIND). Approximately 70% of patients develop CVS after aSAH with 50% long-term morbidity rates. The exact etiology of CVS is unknown; however, a well-described theory involves an antecedent inflammatory cascade with alterations of intracellular calcium dynamics and nitric oxide fluxes, though the intricacies of this inflammatory theory are currently unknown. Consequently, there have been few advances in the clinical treatment of this patient cohort, and morbidity remains high. Identification of intermediaries in the inflammatory cascade can provide insight into newer clinical interventions in the prevention and management of cerebral vasospasm and will hopefully prevent neurological decline. In this review, we discuss current theories implicating the inflammatory cascade in the development of CVS and potential treatment targets.

Advanced imaging modalities in the detection of cerebral vasospasm

The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, ¹³³Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.

Critical care management of subarachnoid hemorrhage

Successful critical care management of patients with aneurysmal subarachnoid hemorrhage (SAH) requires a thorough understanding of the disease and its complications and a familiarity with modern multimodality neuromonitoring technology. This article reviews the natural history of aneurysmal SAH and strategies for disease management in the acute setting, including available tools for monitoring brain function. Intensive care management of patients with SAH focuses on prevention of further neurologic injury. Aneurysmal rebleeding, hydrocephalus, seizures, and delayed ischemic injury represent major threats. There is increasing awareness of extracerebral complications, including electrolyte disturbances (eg, cerebral salt wasting) and cardiac dysfunction. Prompt recognition and treatment of these disorders maximizes the odds of a good functional outcome. Technologic advances hold the promise of improved detection and treatment of secondary neurologic insults.

Atorvastatin preconditioning attenuates the production of endothelin-1 and prevents experimental vasospasm in rats

OBJECTIVE

Induced endothelin-1 (ET-1) production and decreased nitric oxide synthase (NOS) bioavailability have been found in aneurysmal subarachnoid hemorrhage (SAH). Atorvastatin is recognized to have pleiotropic effects including increasing NOS bioavailability as well as reducing inflammation and oxidative damage other than reducing dyslipidemia. This study is of interest to examine the effect of atorvastatin on ET-1/endothelial nitric oxide synthase (eNOS) in experimental SAH.

METHODS

A rodent double-hemorrhage SAH model was employed. Animals were randomly assigned as sham-operated, SAH, vehicle plus SAH, 5 mg/day atorvastatin treatment plus SAH and 5 mg/day atorvastatin precondition plus SAH groups. Administration with atorvastatin (5 mg/day) was initiated 1 week before (precondition) and 24 hr later (treatment). Cerebrospinal fluid samples were collected at 72 hr after second SAH. ET-1 (ELISA) was measured. The basilar arteries (BAs) were harvested and sliced, and their cross-sectional areas were measured. Radiolabeled NOS assay kit was used to detect eNOS.

RESULTS

Morphologically, convoluted internal elastic lamina, distorted endothelial cells and myonecrosis of the smooth muscle were predominantly observed in the BA of SAH and vehicle-treated SAH groups, which was not detected in the atorvastatin-preconditioned SAH group or the healthy controls. Significant vasospasm was noted in the vehicle group (lumen potency 64.5%, compared with the sham group, p </= 0.01) and less prominent in the atorvastatin treatment group (lumen potency, 76.6%, p < 0.05). In addition, increased ET-1 levels were found in all the animals subject to SAH (SAH only, SAH plus vehicle and SAH plus atorvastatin reversal) except in the atorvastatin precognition group when compared with the healthy controls (no SAH). Likewise, the levels of expressed NOS in BAs is induced in the atorvastatin groups (both atorvastatin treatment and precondition) when compared with that in the SAH group (p < 0.01).

CONCLUSION

This study offers first evidence that atorvastatin in the preconditioning status reduces the level of ET-1, which corresponds to its antivasospastic effect in the condition of chronic vasospasm. Although there is increased expression of NOS in both atorvastatin precondition and reversal groups, BA's lumen potency is significantly increased in the atorvastatin precondition group when compared with the SAH group (p < 0.01).

Noninvasive imaging techniques in the diagnosis and management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating condition, requiring prompt diagnosis and therapeutic intervention as well as close monitoring for the development of complications including vasospasm (VS). Although digital subtraction angiography is still considered the gold standard for the diagnosis of aSAH (and vasospasm), new and less invasive modalities are emerging including ultrasound, CT, CT angiography and CT perfusion, and MR imaging. The current evidence for the use of these newer modalities is described for the diagnosis of aSAH and the management of its sequelae including VS.

Critical care management of subarachnoid hemorrhage

Successful critical care management of patients with aneurysmal subarachnoid hemorrhage requires a thorough understanding of the disease and its complications and a familiarity with modern multimodality neuromonitoring technology. This article reviews the natural history of aneurysmal subarachnoid hemorrhage and strategies for disease management in the acute setting. Available tools for monitoring brain function are discussed.

Racial differences in cerebral vasospasm: a systematic review of the literature

OBJECTIVE

Despite a significant body of clinical research and the widespread use of early intervention with aggressive postoperative management, cerebral vasospasm (CV) continues to contribute significantly to the morbidity and mortality of aneurysmal subarachnoid hemorrhage (aSAH). Many studies have evaluated predictive factors, although none to date has investigated a possible difference in the incidence of CV between Asian and white patients. We present a review of the modern aSAH literature to examine the incidence of CV in Japan and Europe, two highly researched populations.

METHODS

A literature search was performed using the Medline and PubMed databases. Studies conducted in Japan or Europe published between 1990 and 2004 that reported an incidence of CV after aSAH were subjected to a thorough review. Data from included studies were categorized by origin (Japan or Europe) and method of CV diagnosis (angiography, delayed ischemic neurological deficit, or new infarct attributable to CV), and then were combined. Recorded incidences then were compared using a chi test, and estimates of the relative risk of vasospasm were computed.

RESULTS

The initial literature search identified 102 studies, and 32 studies met all inclusion criteria. The incidence of vasospasm diagnosed by angiography, delayed ischemic neurological deficit, and computed tomography was significantly greater in Japanese studies (all P < 0.001). The relative risks for Japanese patients as compared with European patients were 2.04, 2.07, and 1.53 for angiographic CV, delayed ischemic neurological deficit, and new infarct, respectively.

CONCLUSION

Patients in Japanese studies were more likely to experience CV after aSAH across diagnostic methods. This may be a manifestation of genetic differences between Japanese and European populations. Clinicians should consider possible patient differences when interpreting CV research conducted in these populations.

Management of cerebral vasospasm

Cerebral vasospasm is delayed narrowing of the large arteries of the circle of Willis occurring 4 to 14 days after aneurysmal subarachnoid hemorrhage (SAH). It is but one cause of delayed deterioration after SAH but, in general, is the most important potentially treatable cause of morbidity and mortality after SAH. Development of vasospasm is best predicted by the volume, location, persistence and density of subarachnoid clot early after SAH. Diagnosis is made by catheter angiography or, with less accuracy, by computed tomographic angiography, transcranial Doppler ultrasound or other methods. Treatment remains problematic because it is expensive, time-consuming, associated with substantial risk and largely ineffective. Treatment includes optimization of factors that affect cerebral blood flow and metabolism, systemic administration of nimodipine, hemodynamic therapy and pharmacologic and mechanical angioplasty.

Evaluation of vasospasm after subarachnoid hemorrhage by use of multislice computed tomographic angiography

OBJECTIVE

Multislice computed tomographic angiography (CTA) can provide clearer vascular images, even of the peripheral arteries, than conventional CTA. Multislice CTA was compared with digital subtraction angiography (DSA) for the detection of cerebral vasospasm in patients with acute aneurysmal subarachnoid hemorrhage (SAH) to analyze whether multislice CTA can replace DSA in the detection of vasospasm after SAH.

METHODS

Within 72 hours after the onset of symptoms, multislice CTA and DSA were performed in 20 patients with SAH. Multislice CTA and DSA were repeated on Day 7 to assess cerebral vasospasm. Regions of interest were established in the proximal and distal segments of the anterior and middle cerebral arteries on both multislice CTA and DSA images, and the agreement between the severity of vasospasm on multislice CTA and DSA images was statistically compared. The multislice Aquilon computed tomography system (Toshiba, Inc., Tokyo, Japan) used the following parameters: 1 mm collimation and 3.5 mm per rotation table increment (pitch, 3.5).

RESULTS

The degree of vasospasm as revealed by multislice CTA correlated significantly with the degree of vasospasm revealed by DSA (P < 0.0001). The agreement between the severity of vasospasm on multislice images obtained via CTA and DSA in the overall, proximal, and distal segments of the cerebral arteries was 91.6, 90.8, and 92.3%, respectively.

CONCLUSION

Multislice CTA can detect angiographic vasospasm after SAH with accuracy equal to that of DSA.