Comparison of 16-row multislice CT angiography with conventional angiography for detection and evaluation of intracranial aneurysms

Shifts in Diagnostic Testing for Headache in the Emergency Department, 2015 to 2021

Importance

Subarachnoid hemorrhage is typically diagnosed by noncontrast head computed tomography (CT); lumbar puncture is recommended if computed tomography is nondiagnostic, although CT cerebral angiography has been promoted as an alternative to lumbar puncture in this diagnostic pathway. The outcomes of this debate in practice have not been studied.

Objective

To determine whether CT cerebral angiography use has increased in lieu of lumbar puncture among emergency department (ED) patients with headache, with an increase in unruptured intracranial aneurysm detection.

Design, Setting, and Participants

This retrospective cohort study took place in 21 community EDs of an integrated health care system in Northern California between 2015 and 2021. Participants were adult (aged >17 years) health plan members with a chief concern of headache. Exclusions were prior diagnoses of subarachnoid hemorrhage, unruptured intracranial aneurysm, cerebral arteriovenous malformation, or cerebrospinal fluid shunt. Data were analyzed from October to November 2023.

Exposures

CT cerebral angiography and/or lumbar puncture during the ED encounter.

Main Outcomes and Measures

Primary and secondary outcomes were 14-day and 90-day unruptured intracranial aneurysm detection, respectively. Safety outcomes were missed diagnoses of subarachnoid hemorrhage or bacterial meningitis. The annual incidence of unruptured intracranial aneurysm detection was normalized to the incidence of subarachnoid hemorrhage (UIA:SAH ratio). Average annualized percentage changes were quantified using joinpoint regression analysis.

Results

Among 198 109 included ED encounters, the mean (SD) age was 47.5 (18.4) years; 140 001 patients (70.7%) were female; 29 035 (14.7%) were Black or African American, 59 896 (30.2%) were Hispanic or Latino, and 75 602 (38.2%) were White. Per year, CT cerebral angiography use increased (18.8%; 95% CI, 17.7% to 20.3%) and lumbar punctures decreased (-11.1%; 95% CI, -12.0% to -10.4%), with a corresponding increase in the 14-day UIA:SAH ratio (3.5%; 95% CI, 0.9% to 7.4%). Overall, computed tomography cerebral angiography use increased 6-fold relative to lumbar puncture, with a 33% increase in the detection of UIA. Results were similar at 90 days and robust to sensitivity analyses. Subarachnoid hemorrhage (1004 cases) and bacterial meningitis (118 cases) were misdiagnosed in 5% and 18% of cases, respectively, with no annual trends (P = .34; z1003 = .95 and P = .74; z117 = -.34, respectively).

Conclusions and Relevance

In this cohort study of ED patients with headache, increases in CT cerebral angiography use were associated with fewer lumbar punctures and higher detection of unruptured intracranial aneurysms, with no significant change in missed diagnoses of subarachnoid hemorrhage or bacterial meningitis. While this shift in diagnostic strategy appeared safe in the short-term, the long-term consequences remain unclear.

Dynamic evaluation of unruptured intracranial aneurysms by 4D-CT angiography: comparison with digital subtraction angiography (DSA) and surgical findings

BACKGROUND

This study was to prospectively investigate the feasibility of four-dimensional computed tomography angiography (4D-CTA) with electrocardiogram-gated (ECG) reconstruction for preoperative evaluation of morphological parameters, and compared with digital subtraction angiography (DSA). We also aimed to detect pulsation in unruptured intracranial aneurysms (UIAs) by using 4D-CTA, as a potential predicting factor of growth or rupture.

MATERIALS

64 patients with 64 UIAs underwent ECG-gated dynamic 4D-CTA imaging before treatment, of which 46 patients additionally underwent DSA. Original scanning data were reconstructed to produce 20 data sets of cardiac cycles with 5%-time intervals. The extent of agreement on UIAs morphological features assessed with 4D-CTA and DSA was estimated using the k coefficient of the Kappa test. The radiation doses were also calculated and compared between 4D-CTA and DSA. In the aneurysmal surgically treated in our institution, we were able to compare the surgical findings of the aneurysm wall with 4D-CTA images. We performed long-term follow-up on untreated patients.

RESULTS

The morphological characteristics detected by 4D-CTA and DSA were consistent in aneurysm location (k = 1.0), shape (k = 0.76), maximum diameter (k = 0.94), aneurysm neck (k = 0.79) and proximity to parent and branch vessels (k = 0.85). 4D-CTA required lower radiation doses (0.32 ± 0.11 mSv) than DSA (0.84 ± 0.37 mSv, P < 0.001). Pulsation was detected in 26 of the 64 unruptured aneurysms, and all underwent neurosurgical clipping or interventional embolization. In aneurysms surgically treated in our hospital, we observed a significant correlation between 4D-CTA findings and surgical evaluation of the aneurysmal wall, in particular the irregular pulsations detected on 4D-CTA have demonstrated to correspond to dark-reddish thinner wall at surgery.

CONCLUSIONS

In this proof-of-concept study, 4D-CTA provided real-time, non-invasive preoperative assessments of UIAs comparable to DSA. Moreover, optimal correlation between the irregular pulsation detected by 4D-CTA and the surgical findings support a possible role of this technique to identify aneurysms with a higher risk of rupture.

Cerebral Digital Subtraction Angiography in Acute Intracranial Hemorrhage: Considerations in Critically Ill Children

Cerebrovascular disorders are an important cause of morbidity and mortality in children. Although minimally invasive, cerebral digital subtraction angiography (DSA) has been shown to be safe in children and is a valuable, and perhaps underutilized, technique for the diagnosis and management of pediatric cerebrovascular disorders in the critical care setting. Through a case-based approach, we explore the utility of DSA in critically ill children with acute intracranial hemorrhage (ICH). We discuss the use of DSA in the acute management of aneurysm and arteriovenous malformation rupture as well as cerebral vasospasm. Those caring for critically ill children with acute ICH should consider cerebral DSA as part of a comprehensive approach to the diagnosis and management of these conditions.

Angiographic analysis on posterior fossa hemorrhages and vascular malformations beyond aneurysms by CT angiography and digital subtraction angiography

Background

Posterior fossa malformations are less common than supratentorial malformations, but hemorrhages in posterior fossa are more serious due to presence of vital structures within this region. Most common cause of bleed in posterior fossa apart from hypertension is aneurysms but other vascular malformations are also there which cause hemorrhage. Here we discuss other causes of posterior fossa bleed beyond aneurysms.

Results

A total of 80 patients were evaluated: 47 (58.8%) had aneurysms, 29 (36.3%) had arteriovenous malformations, one each had developmental venous anomaly and brainstem cavernoma. Thirty vascular malformations were detected, of which 18 (62.1%) were pial arteriovenous malformations (AVMs), 11 (37.9%) were dural arteriovenous fistulas (dAVF), and one had developmental venous anomaly (DVA). Six patients of AVM underwent both DSA and CTA, and CTA could correctly diagnose only 2 of 4 pial AVMs detected by DSA. Among two dAVFs detected by DSA, CTA could demonstrate dAVF only in one patient.

Conclusion

CTA could be used as alternative to DSA in diagnosis and characterizing aneurysms in posterior fossa but for AVMs, 3D-CTA cannot replace DSA; however potential of time-resolved CTA (TR-CTA) appears promising.

Cost-Effective Analysis of Different Diagnostic Strategies in Screening for Aneurysms After Spontaneous Subarachnoid Hemorrhage

PURPOSE

With an increasing number of patients being treated by coiling for aneurysms, using computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) as an initial screening test becomes less important because digital subtraction angiography (DSA) is the first step of endovascular treatment procedure. The objective of this study is to investigate whether CTA or MRA remained to be the optimal screening strategy in patients with spontaneous subarachnoid hemorrhage (SAH).

METHODS

CTA, MRA, and DSA strategy were evaluated in a decision tree model created with TreeAge Pro Suite 2011. Input parameters were derived from published literature and our institutional database. Base case and sensitivity analyses were conducted to assess the cost-effectiveness of each strategy. A Monte Carlo simulation was performed with all parameters ranged among their distributions to evaluate the validation of results.

RESULTS

The base case scenario showed that MRA was the most cost-effective strategy. Using a willingness-to-pay threshold of ¥70,892/quality adjusted life year, MRA remained to be most cost-effective when its sensitivity is >0.907. DSA was not cost-effective compared to CTA or MRA unless over 91.56% of patients were treated by coiling. The Monte Carlo simulation reported DSA not to be a cost-effective strategy at willingness-to-pay of ¥70,892 in 99.99% of the iterations.

CONCLUSION

DSA is not cost-effective compared to CTA or MRA and should not be used as the initial diagnostic tool for spontaneous SAH.

The Potential Value of 320-Row Computed Tomography Angiography in Digital Subtraction Angiography-Negative Spontaneous Subarachnoid Hemorrhage Patients

Objective

This study aimed to investigate the clinical value of multiphase and multiparametric 320-row computed tomography (CT) in the long-term follow-up of spontaneous subarachnoid hemorrhage (SAH) with initially negative CT angiography (CTA) and digital subtraction angiography (DSA) results.

Methods

We retrospectively analyzed the clinical data of 35 patients with nontraumatic angiographically negative SAH results from February 2012 to December 2015. Regular follow-up was performed with 320-row CTA, CT venography, and CT perfusion.

Results

All patients received 320-row CT follow-up for 0.5 to 4 years. The diagnostic yield of the follow-up examinations was 4 of 35 (11.4%), 3 of 31 (9.7%), and 1 of 28 (3.6%) for the first, second, and third time points, respectively. Two patients were admitted to the hospital because of recurrent subarachnoid hemorrhage during the follow-up period and diagnosed with ruptured aneurysms.

Conclusions

Patients with SAH with negative findings in the first DSA examination require to follow up. Follow-up using 320-row CTA, CT venography, and CT perfusion allows for a noninvasive diagnostic test for cerebrovascular diseases with higher compliance and fewer complications when compared with follow-up using DSA.

ACR Appropriateness Criteria® Cerebrovascular Diseases-Aneurysm, Vascular Malformation, and Subarachnoid Hemorrhage

Cerebrovascular disease is a broad topic. This document focuses on the imaging recommendations for the varied clinical scenarios involving intracranial aneurysms, vascular malformations, and vasculitis, which all carry high risk of morbidity and mortality. Additional imaging recommendations regarding complications of these conditions, including subarachnoid hemorrhage and vasospasm, are also covered. While each variant presentation has unique imaging recommendations, the major focus of this document is neurovascular imaging techniques. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Subarachnoid Hemorrhage

PURPOSE OF REVIEW

Subarachnoid hemorrhage (SAH) remains an important cause of mortality and long-term morbidity. This article uses a case-based approach to guide readers through the fundamental epidemiology and pathogenesis of SAH, the approach to diagnosis and management, the results of clinical trials and evidence to date, prognostic considerations, controversies, recent developments, and future directions in SAH.

RECENT FINDINGS

Historically, management of SAH focused on prevention and treatment of subsequent cerebral vasospasm, which was thought to be the primary cause of delayed cerebral ischemia. Clinical and translational studies over the past decade, including several therapeutic phase 3 randomized clinical trials, suggest that the pathophysiology of SAH-associated brain injury is multiphasic and multifactorial beyond large vessel cerebral vasospasm. The quest to reduce SAH-associated brain injury and improve outcomes is shifting away from large vessel cerebral vasospasm to a new paradigm targeting multiple brain injury mechanisms, including early brain injury, delayed cerebral ischemia, microcirculatory dysfunction, spreading cortical depolarization, inflammation, and the brain-body interaction in vascular brain injury with critical illness.Despite multiple negative randomized clinical trials in search of potential therapeutic agents ameliorating the downstream effects after SAH, the overall outcome of SAH has improved over recent decades, likely related to improvements in interventional options for ruptured cerebral aneurysms and in critical care management. Emerging clinical evidence also suggests potential harmful impact of historic empiric treatments for SAH-associated vasospasm, such as prophylactic induction of hypertension, hypervolemia, and hemodilution (triple H therapy).With decreasing mortality, long-term SAH survivorship and efforts to reduce chronic morbidity and to improve quality of life and patient-centered outcome are growing areas of unmet need. Despite existing guidelines, significant variabilities in local and regional practices and in scientific terminologies have historically limited advancement in SAH care and therapeutic development. Large global collaborative efforts developed harmonized SAH common data elements in 2019, and studies are under way to examine how existing variabilities in SAH care impact long-term SAH outcomes.

SUMMARY

Although the overall incidence and mortality of SAH is decreasing with advances in preventive and acute care, SAH remains a major cause of long-term morbidity in survivors. Significant variabilities in care settings and empiric treatment protocols and inconsistent scientific terminologies have limited advancement in patient care and therapeutic clinical studies. Large consensus efforts are under way to introduce clinical guidelines and common data elements to advance therapeutic approaches and improve patient outcome.

Current and novel non-invasive imaging modalities in vascular neurosurgical practice

Radiological investigations are a powerful tool in the assessment of patients with intracranial vascular anomalies. 'Visual' assessment of neurovascular lesions is central to their diagnosis, monitoring, prognostication and management. Computed tomography and magnetic resonance imaging are the two principal non-invasive imaging modalities used in clinical practice for the assessment of the cerebral vasculature, but these techniques continue to evolve, enabling clinicians to gain greater insights into neurovascular pathology and pathophysiology. This review outlines both established and novel imaging modalities used in modern neurovascular practice and their clinical applications.

Headache in the Emergency Department: Avoiding Misdiagnosis of Dangerous Secondary Causes, An Update

In the initial assessment of the headache patient, the emergency physician must consider several dangerous secondary causes of headache. A thorough history and physical examination, along with consideration of a comprehensive differential diagnosis may alert the emergency physician to the diagnosis of a secondary headache particularly when the history is accompanied by any of the following clinical features: sudden/severe onset, focal neurologic deficits, altered mental status, advanced age, active or recent pregnancy, coagulopathy, malignancy, fever, visual deficits, and/or loss of consciousness.

Functional Outcome Following Ultra-Early Treatment for Ruptured Aneurysms in Patients with Poor-Grade Subarachnoid Hemorrhage

BACKGROUND

Little is known regarding functional outcome following poor-grade (World Federation of Neurosurgical Societies grades IV and V) aneurysmal subarachnoid hemorrhage (aSAH), especially in individuals treated aggressively in the early phase after ictus.

METHODS

We provided patients with aSAH with ultra-early definitive treatment, coiling or clipping, within 6 hours from arrival as per protocol. We classified the patients into 3 groups according to their computed tomography findings: Group 1, intraventricular hemorrhage with obstructive hydrocephalus; Group 2, massive intracerebral hemorrhage with brain herniation; and Group 3, neither Group 1 nor Group 2. We retrospectively evaluated patients with poor-grade aSAH who were admitted to our department between January 2013 and December 2016. We evaluated functional outcome at 6 months, defining modified Rankin Scale (mRS) scores of 0-2 as good and those of 3-6 as poor outcomes.

RESULTS

A good functional outcome was observed in 39.4% (28/71) of all cases. All-cause mortality at 6 months was 15.5% (11/71). A good outcome in Group 3 was significantly higher than that in the other two groups (Group 1 and 2 vs. Group 3, 20.8% vs. 48.9%, p = 0.02), even after adjustment with a multiple logistic regression analysis (odds ratio 6.1, 95% confidence interval 1.1 to 34.8).

CONCLUSIONS

Approximately 40% of patients with poor-grade aSAH became functionally independent, and approximately half of the patients with poor-grade aSAH who had neither intraventricular hemorrhage with obstructive hydrocephalus nor with brain herniation had good functional outcomes. Although further trials are required to confirm our results, ultra-early surgery may be considered for patients with poor-grade aSAH.

Detection and Evaluation of Intracranial Aneurysms in the Posterior Fossa by Multidetector Computed Tomography Angiography - Comparison with Digital Subtraction Angiography

Introduction:

Posterior fossa hemorrhages are not so frequent but as posterior cranial fossa space is narrow and has many vital structures, even a small amount of bleed can lead to compression of brain stem and serious consequences. Identification and planning management of cause of bleed requires angiogram. Digital subtraction angiography (DSA) being invasive modality but is gold standard, so noninvasive computed tomography angiography (CTA) is compared to detect cause of bleed in the posterior fossa in this study.

Materials and Methods:

From January 2017 to October 2018, all patients with posterior fossa bleed who underwent CTA and DSA for evaluation were compared regarding identification of aneurysm as cause of bleed.

Results:

A total of 49 patients were evaluated in this study during study duration, of which 26 (53%) were male and 23 (47%) were female. Out of 49 patients evaluated, 47 patients had aneurysms detected on DSA. Of 25 patients who underwent both procedures, 23 patients had aneurysms, and correct diagnosis was made with CTA in 24 out of 25 aneurysms. One aneurysm missed by CTA was close to bony structure.

Discussion:

With advancement of CTA technology, sensitivity of detecting intracranial aneurysms has increased to >96%. The overall sensitivity in detecting aneurysms is 96% with sensitivity in detecting aneurysms >4 mm being 100%. The sensitivity of CTA for smaller sized aneurysms is low which is attributed partially to lower spatial resolution of CT compared to DSA.

Conclusion:

CTA is a simple, fast, and noninvasive imaging modality that can be used to detect and characterize intracranial aneurysms in the posterior fossa.

ACR Appropriateness Criteria® Cerebrovascular Disease

Diseases of the cerebral vasculature represent a heterogeneous group of ischemic and hemorrhagic etiologies, which often manifest clinically as an acute neurologic deficit also known as stroke or less commonly with symptoms such as headache or seizures. Stroke is the fourth leading cause of death and is a leading cause of serious long-term disability in the United States. Eighty-seven percent of strokes are ischemic, 10% are due to intracerebral hemorrhage, and 3% are secondary to subarachnoid hemorrhage. The past two decades have seen significant developments in the screening, diagnosis, and treatment of ischemic and hemorrhagic causes of stroke with advancements in CT and MRI technology and novel treatment devices and techniques. Multiple different imaging modalities can be used in the evaluation of cerebrovascular disease. The different imaging modalities all have their own niches and their own advantages and disadvantages in the evaluation of cerebrovascular disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Comparison Between CTA and Digital Subtraction Angiography in the Diagnosis of Ruptured Aneurysms

BACKGROUND

Computerized tomography angiography (CTA) is commonly used to diagnose ruptured cerebral aneurysms with sensitivities reported as high as 97% to 100%. Studies validating CTA accuracy in the setting of subarachnoid hemorrhage (SAH) are scarce and limited by small sample sizes.

OBJECTIVE

To evaluate the diagnostic accuracy of CTA in detecting intracranial aneurysms in the setting of SAH.

METHODS

A single-center, retrospective cohort of 643 patients was reviewed. A total of 401 patients were identified whose diagnostic workup included both CTA and confirmatory digital subtraction angiography (DSA). Aneurysms missed by CTA but diagnosed by DSA were further stratified by size and location.

RESULTS

Three hundred and thirty aneurysms were detected by CTA while DSA detected a total of 431 aneurysms. False positive CTA results were seen for 24 aneurysms. DSA identified 125 aneurysms that were missed by CTA and 83.2% of those were <5 mm in diameter. The sensitivity of CTA was 57.6% for aneurysms smaller than 5 mm in size, and 45% for aneurysms originating from the internal carotid artery. The overall sensitivity of CTA in the setting of SAH was 70.7%.

CONCLUSION

The accuracy of CTA in the diagnosis of ruptured intracranial aneurysm may be lower than previously reported. CTA has a low sensitivity for aneurysms less than 5 mm in size, in locations adjacent to bony structures, and for those arising from small caliber parent vessels. It is our recommendation that CTA should be used with caution when used alone in the diagnosis of ruptured intracranial aneurysms.

Small Intracranial Aneurysms: Diagnostic Accuracy of CT Angiography

Purpose To assess the accuracy of computed tomographic (CT) angiography for diagnosis of cerebral aneurysms 5 mm or smaller, with digital subtraction angiography (DSA) as the reference standard, in a large patient cohort Materials and Methods This retrospective study was approved by the local institutional review board with a waiver of written informed consent. A total of 1366 patients who underwent cerebral CT angiography followed by DSA were included. The performance of CT angiography for depiction of aneurysms was evaluated by two readers on a per-patient and per-aneurysm basis and based on size of aneurysm, location, and status of rupture. The performance of CT angiography for diagnosis of aneurysms of different size, location, and rupture status was compared by using χ² test. κ statistic was used to assess interreader agreement for diagnosis of aneurysms. Results Of 1366 patients, 579 patients had 711 small aneurysms at DSA. By using DSA as the reference standard, the respective sensitivity, specificity, and accuracy of CT angiography for readers 1 and 2 for detection of small aneurysms on a per-patient basis were 97.1% (562 of 579) and 97.4% (564 of 579), 98.5% (451 of 458) and 99.1% (454 of 458), and 97.7% (1013 of 1037) and 98.2% (1018 of 1037) and those on a per-aneurysm basis were 95.2% (677 of 711) and 95.4% (678 of 711), 96.6% (451 of 467) and 97.0% (454 of 468), and 95.8% (1128 of 1178) and 96.0% (1132 of 1179). The sensitivities of CT angiography were lower for detection of aneurysms smaller than 3 mm and unruptured compared with aneurysms that were 3-5 mm and ruptured (P < .001). No difference existed for the sensitivities of CT angiography for diagnosis of aneurysms in the anterior versus posterior circulation (P > .0167). Excellent or good interreader agreement was found for detection of intracranial aneurysms on a per-patient (κ = 0.982) and per-aneurysm (κ = 0.748) basis. Conclusion This large cohort study demonstrated that CT angiography had high accuracy for detection of small cerebral aneurysms, including those smaller than 3 mm. ^© RSNA, 2017 Online supplemental material is available for this article.

Digital subtraction CT angiography for the detection of posterior inferior cerebellar artery aneurysms: comparison with digital subtraction angiography

OBJECTIVE

To evaluate the diagnostic accuracy of digital subtraction CT angiography (DS-CTA) in detecting posterior inferior cerebellar artery (PICA) aneurysms with digital subtraction angiography (DSA) as reference standard.

METHODS

A total of 115 patients, including 56 patients diagnosed with PICA aneurysms by CTA or DSA and 59 non-PICA-aneurysm patients were included in this retrospective study. All patients underwent DS-CTA and DSA. The site of PICA aneurysms and the pattern of haemorrhage were analysed. Sensitivity and specificity of DS-CTA without and with combining haemorrhage pattern in diagnosing PICA aneurysms were evaluated on a per patient and per aneurysm basis with DSA.

RESULTS

Of 115 patients, 56 patients (48.7%) had 61 PICA aneurysms (size range, 1.1-13.5 mm; mean size, 4.9 ± 2.8 mm) on DSA. The sensitivity and specificity in depicting PICA aneurysms were 89.3% and 96.6% on a per patient basis and 90.2% and 93.4% on a per aneurysm basis, while the corresponding values were 94.6% and 96.6% on a per patient basis and 95.1% and 93.4% on a per aneurysm basis when combining with haemorrhage site.

CONCLUSION

DS-CTA has a high sensitivity and specificity in detecting PICA aneurysms compared with DSA. It may be helpful for clinical diagnosis of PICA aneurysms to combine with haemorrhage sites.

KEY POINTS

• CT angiography has a good diagnostic performance in detecting PICA aneurysms. • The haemorrhage location is helpful to detect PICA aneurysms. • Digital subtraction CTA is a preferable diagnostic means for PICA aneurysms.

Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms

BACKGROUND AND PURPOSE

Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms.

MATERIALS AND METHODS

Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared.

RESULTS

Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B.

CONCLUSIONS

In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.

Diagnosis and Management of Subarachnoid Hemorrhage

PURPOSE OF REVIEW

The purpose of this article is to present the epidemiology, clinical presentation, and management of patients with subarachnoid hemorrhage (SAH). SAH is a neurologic emergency that carries high morbidity and mortality. Patients with SAH are at risk for several significant neurologic complications, including hydrocephalus, cerebral edema, delayed cerebral ischemia, rebleeding, seizures, and neuroendocrine abnormalities that lead to impaired body regulation of sodium, water, and glucose.

RECENT FINDINGS

The incidence of SAH has remained stable, but mortality of hospitalized patients has significantly declined over the past 3 decades. Many common therapies for SAH have created controversy, and various recent neuroprotective clinical trials have produced negative results. However, the publication of two consensus guidelines by the American Heart Association/American Stroke Association and the Neurocritical Care Society have provided a clarification for what should constitute best practice for patients with SAH. The most important of those recommendations include the following: admission of patients to high-volume centers (defined as more than 35 patients with SAH per year) under the management of a specialized and multidisciplinary team; early identification and management of the bleeding source; evaluation and treatment decision for unsecured aneurysms by a multidisciplinary team made up of cerebrovascular neurosurgeons, endovascular practitioners, and neurointensivists; management of patients in the neurocritical care unit with oral nimodipine, blood pressure control, euvolemia, and frequent monitoring for neurologic and systemic complications; and delayed cerebral ischemia secondary to cerebral vasospasm should be treated with induced hypertension and endovascular therapies once confirmed.

SUMMARY

SAH is a devastating neurologic disease. Management of patients with SAH should adhere to currently available treatment guidelines. Several aspects of SAH management remain controversial and need further studies to clarify their role in improving patient outcome.

Subtraction CT angiography for the detection of intracranial aneurysms: A meta-analysis

The aim of this meta-analysis was to investigate the accuracy of subtraction computed tomography angiography (CTA) for diagnosing intracranial aneurysms. A systematic literature search up to January 1, 2013 was performed in PubMed. Two independent reviewers selected 8 studies that compared subtraction CTA with digital subtraction angiography. Data from the studies were used to construct a 2×2 contingency table on a per-patient basis in ≥5 diseased and 5 non-diseased patients, with additional data on a per-aneurysm basis. Overall, subtraction CTA had a pooled sensitivity of 99% [95% confidence interval (CI), 95-100%] and specificity of 94% (95% CI, 86-97%) for detecting and ruling out cerebral aneurysms, respectively, on a per-patient basis. On a per-aneurysm basis, the pooled sensitivity was 96% (95% CI, 90-99%), and the specificity was 91% (95% CI, 85-95%). In conclusion, subtraction CTA is a highly sensitive, specific and non-invasive method for the diagnosis and evaluation of intracranial aneurysms.

Diagnostic Impact of Bone-Subtraction CT Angiography for Patients with Acute Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Detection and evaluation of ruptured aneurysms is critical for choosing an appropriate endovascular or neurosurgical intervention. Our aim was to assess whether bone-subtraction CTA is capable of guiding treatment for cerebral aneurysms in patients with acute SAH and could replace DSA.

MATERIALS AND METHODS

We prospectively studied 116 consecutive patients with SAH with 16-detector row bone-subtraction CTA and DSA before intracranial aneurysm treatment. Two independent neuroradiologists reviewed the bone-subtraction CTA blinded to DSA (reference standard). We determined the accuracy of bone-subtraction CTA for aneurysm detection and the measurement of aneurysm dimensions and compared the radiation doses of the 2 imaging modalities.

RESULTS

Seventy-one patients (61%) had 74 aneurysms on DSA. Bone-subtraction CTA detected 73 of these aneurysms, but it detected 1 additional aneurysm. On a per-aneurysm basis, sensitivity, specificity, and positive and negative predictive values for bone-subtraction CTA were 99%, 98%, and 99% and 98%, respectively. For aneurysms of ≤3 mm, sensitivity was 94% (95% CI, 73%-99%). Bone-subtraction CTA slightly overestimated neck and dome diameters by <0.2 mm and overestimated the dome-to-neck ratios by 2% on average. Dose-length product was 565 ± 201 mGy × cm for bone-subtraction CTA and 1609 ± 1300 mGy × cm for DSA.

CONCLUSIONS

Bone-subtraction CTA is as accurate as DSA in detecting cerebral aneurysms after SAH, provides similar information about aneurysm configuration and measures, and reduces the average effective radiation dose for vascular diagnostics by 65%. Diagnostic equivalence in association with dose reduction suggests replacing DSA with bone-subtraction CTA in the diagnostic work-up of spontaneous SAH.

CT angiography in non-traumatic subarachnoid hemorrhage: the importance of arterial attenuation for the detection of intracranial aneurysms

BACKGROUND

Computed tomography angiography (CTA) is today the primary method for the detection of intracranial aneurysms. The technique has evolved considerably during the last decade, and it is important to establish criteria for high image quality, especially with regard to improving the diagnosis of small aneurysms.

PURPOSE

To evaluate diagnostic accuracy and image quality by arterial attenuation of CTA in patients with non-traumatic subarachnoid hemorrhage (SAH).

MATERIAL AND METHODS

Between 2005 and 2011, CTA and digital subtraction angiography (DSA) were performed in 326 patients with non-traumatic SAH. Sensitivity and specificity for aneurysm detection were evaluated per patient, per aneurysm, and per ruptured aneurysm. The image quality of CTA was evaluated by arterial attenuation measurements (mean Hounsfield units [HU]) in the internal carotid artery (ICA).

RESULTS

In all, 285 aneurysms in 235 patients were detected by DSA, 19 aneurysms were missed on CTA, and 223 aneurysms were classified as ruptured. In 91 patients, no aneurysm was found. Correct diagnosis with CTA was made in 28 patients with perimesencephalic hemorrhage. Sensitivity and specificity (95% confidence interval) calculated per patient were 91.6% (87.3-94.9) and 87.9% (79.8-93.6), respectively, per aneurysm 93.3% (89.7-95.9) and 88% (79.9-93.6), and per ruptured aneurysm 94.9% (91.3-97.3) and 96.7% (90.7-99.3). Arterial attenuation (in HU) in CTA revealing true positive ruptured aneurysms and true negative aneurysms (mean 535 ± 110 HU) differed significantly (P = 0.02) from false negative ruptured aneurysms (mean 424 ± 30 HU).

CONCLUSION

CTA has high sensitivity and specificity for the detection of ruptured aneurysms. The sensitivity is related to arterial attenuation in the ICA.

Imaging of Nontraumatic Neuroradiology Emergencies

Imaging of acute neurologic disease in the emergency department can be challenging because of the wide range of possible causes and the overlapping imaging appearance of many of these entities on nonenhanced computed tomography (CT). The key to formulating a succinct, pertinent differential diagnosis includes characterizing the pattern of abnormalities on CT and identifying key features that suggest a particular diagnosis. This article divides neurologic emergencies into 5 scenarios based on the CT findings, including subarachnoid hemorrhage, intraparenchymal hemorrhage, vasogenic edema without and with underlying mass lesion, and acute hydrocephalus. Specific common or important diagnoses in each category are discussed.

Radiation dose and image quality of 70 kVp cerebral CT angiography with optimized sinogram-affirmed iterative reconstruction: comparison with 120 kVp cerebral CT angiography

OBJECTIVES

To evaluate radiation dose, image quality, and optimal level of sinogram-affirmed iterative reconstruction (SAFIRE) of cerebral CT angiography (CTA) at 70 kVp.

METHODS

One hundred patients were prospectively classified into two groups: Group A (n = 50), 70 kVp cerebral CTA with 5 levels of SAFIRE reconstruction (S1-S5); and Group B (n = 50), 120 kVp with filtered back projection (FBP) reconstruction. CT attenuation values, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured. Subjective image quality was evaluated. Effective dose (ED) was estimated.

RESULTS

CT attenuation and noise of the ICA and MCA in Group A were higher than those of Group B (all P < 0.001) while the SNRICA, SNRMCA, CNRICA, and CNRMCA of Group A at S4-5 were comparable to (P > 0.05) or higher than in Group B (P < 0.05). There was no difference in overall image quality between Group A S3-5 and Group B (P > 0.05). ED was 0.2 ± 0.0 mSv for Group A with 85 % ED reduction in comparison to Group B (1.3 ± 0.2 mSv).

CONCLUSION

Cerebral CTA at 70 kVp is feasible, allowing for substantial radiation dose reduction. SAFIRE S4 level is recommended for obtaining optimal image quality.

KEY POINTS

• 70 kVp cerebral CTA is feasible and provides diagnostic image quality. • 70 kVp cerebral CTA resulted in 85% effective dose reduction. • S4 level of SAFIRE is recommended for 70 kVp cerebral CTA.

Clinical practice guideline for the management of intracranial aneurysms

Purpose

An intracranial aneurysm, with or without subarachnoid hemorrhage (SAH), is a relevant health problem. The rupture of an intracranial aneurysm is a critical concern for individual health; even an unruptured intracranial aneurysm is an anxious condition for the individual. The aim of this guideline is to present current and comprehensive recommendations for the management of intracranial aneurysms, with or without rupture.

Materials and Methods

We performed an extensive literature search, using Medline. We met in person to discuss recommendations. This document is reviewed by the Task Force Team of the Korean Society of Interventional Neuroradiology (KSIN).

Results

We divided the current guideline for ruptured intracranial aneurysms (RIAs) and unruptured intracranial aneurysms (UIAs). The guideline for RIAs focuses on diagnosis and treatment. And the guideline for UIAs focuses on the definition of a high-risk patient, screening, principle for treatment and selection of treatment method.

Conclusion

This guideline provides practical, evidence-based advice for the management of patients with an intracranial aneurysm, with or without rupture.

Intra-arterial intraoperative computed tomography angiography guided navigation: a new technique for localization of vascular pathology

BACKGROUND

Precise intraoperative surgical localization of small distal aneurysms, arteriovenous malformations (AVMs), and cranial base dural arteriovenous fistulae may be challenging. Current neuronavigational techniques are based on imaging techniques with limited sensitivity to detect vascular lesions that are small. We introduce the technique of intraoperative computed tomography angiography (iCTA) with an intra-arterial injection for surgical navigation.

OBJECTIVE

To determine whether iCTA integrated with a navigation platform is accurate and useful for precise localization of small vascular lesions that are challenging to treat.

METHODS

This study included 8 patients: 2 with aneurysms, 3 with small cortical AVMs, and 3 with cranial base dural arteriovenous fistulae. iCTA with intra-arterial contrast injection was performed in all patients for precise localization of the small vascular lesion to facilitate craniotomy planning and microsurgical approach. All operative reports, inpatient and outpatient records, and radiographic studies available were reviewed retrospectively.

RESULTS

: The iCTA was used to target 2 aneurysms, 3 small subcortical AVMs, and 3 dural arteriovenous fistulae. This technique was most helpful to localize the 3 AVMs and the distal M4 aneurysm precisely. Craniotomy planning was accurate in all instances; no complications related to the technique were noted, and all patients had uneventful postoperative recoveries.

CONCLUSION

iCTA is an effective and accurate novel technique that can enhance the safety of surgical treatment for small intra-axial vascular pathology.

ABBREVIATIONS

AVM, arteriovenous malformationCTA, computed tomography angiographyDAVF, dural arteriovenous fistulaDSA, digital subtraction angiographyiCTA, intraoperative computed tomography angiographyMCA, middle cerebral arteryMSCT, multislice computed tomographyMRA, magnetic resonance angiography.

Thunderclap headache: diagnostic considerations and neuroimaging features

Thunderclap headache (TCH) is an acute and severe headache that has maximum intensity at onset; TCH can be primary or secondary. Primary TCH is diagnosed when no underlying cause is discovered; however, imaging is crucial in distinguishing secondary causes, which are wide-ranging. The radiologist should be aware of the list of potential diagnoses. Subarachnoid haemorrhage (SAH) is the most common cause of secondary TCH. Aneurysmal SAH accounts for the majority of cases, although other causes should also be considered and these include perimesencephalic haemorrhage, arteriovenous malformations, and dural arteriovenous fistula as well as reversible cerebral vasoconstriction syndrome. Conditions that may present with TCH, with or without SAH include cervical artery dissection and cerebral venous sinus thrombosis. Ischaemic stroke, pituitary apoplexy, and posterior reversible leucoencephalopathy are other potential causes, whereas non-vascular causes include colloid cysts of the third ventricle and spontaneous intracranial hypotension. Imaging features are reviewed with reference to clues gleaned from initial imaging using computed tomography, as well as characteristics that should be sought using magnetic resonance imaging or angiographic imaging.

320-detector row CT angiography for detection and evaluation of intracranial aneurysms: comparison with conventional digital subtraction angiography

AIM

To compare the diagnostic performance of 320-detector row computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms.

MATERIALS AND METHODS

Fifty-two consecutive patients with non-traumatic subarachnoid haemorrhage (SAH) and suspected intracranial aneurysms were evaluated from January 2009 to October 2011. All underwent both 320-detector row volume CTA examination and DSA. CTA volume data were transmitted to a VITREA workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and assessed the results. The three-dimensional (3D) CTA and DSA images were assessed using intraoperative findings as the reference standard.

RESULTS

In 52 patients, 54 aneurysms were detected; 48 patients underwent surgery for 50 aneurysms. The overall sensitivity, specificity, and accuracy of 3D CTA were 96.3, 100, and 94.6%, respectively. Meanwhile, the overall sensitivity, specificity, and accuracy of DSA were 98.1, 98.1, and 95.1%, respectively. For aneurysms less than 3 mm, the sensitivity, specificity, and accuracy of 3D CTA were 81.8, 100, and 93.3%, respectively. The sensitivity, specificity, and accuracy of DSA for small aneurysms were 90.9, 100, and 96.2%, respectively. 3D CTA was superior to DSA in demonstrating aneurysmal calcification, parent artery, and surrounding vascular anatomy.

CONCLUSIONS

3D CTA is a highly sensitive, specific, and non-invasive imaging method for diagnosis and evaluation of intracranial aneurysms. It also allows for precise depiction of aneurysm morphology. Therefore, 320-detector row CTA may be used as an alternative to DSA as a first-line imaging technique in patients with SAH.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Digital subtraction CT angiography for detection of intracranial aneurysms: comparison with three-dimensional digital subtraction angiography

PURPOSE

To evaluate the diagnostic accuracy of digital subtraction computed tomographic (CT) angiography in the detection of intracranial aneurysms compared with three-dimensional (3D) rotational digital subtraction angiography (DSA), as reference standard, in a large cohort in a single center.

MATERIALS AND METHODS

The study was waived by the institutional review board because of its retrospective nature. A total of 513 patients clinically suspected of having or with known intracranial aneurysms and other cerebral vascular diseases underwent both digital subtraction CT angiography with a dual-source CT scanner and 3D DSA, with a median interval of 1 day; 436 patients (84.9%) had acute subarachnoid hemorrhage at presentation. The sensitivity, specificity, and accuracy of digital subtraction CT angiography in depicting aneurysm were analyzed on a per-patient and per-aneurysm basis, with 3D DSA as the reference standard. The sensitivity, specificity, and accuracy of digital subtraction CT angiography in depicting aneurysms of different diameter (ie, <3 mm, 3-5 mm, 5-10 mm, and >10 mm) and of aneurysms at different locations in the anterior and posterior circulation were calculated. Kappa statistics were calculated to quantify inter- and intrareader variability in detecting aneurysms by using digital subtraction CT angiography for 100 patients.

RESULTS

Of 513 patients, 106 (20.7%) had no aneurysms, while 407 patients (79.3%) had 459 aneurysms at 3D DSA. Digital subtraction CT angiography correctly depicted 456 (99.3%) of the 459 aneurysms. By using 3D DSA as the standard of reference, the sensitivity and specificity of depicting intracranial aneurysms were 97.8% (398 of 407) and 88.7% (94 of 106), respectively, on a per-patient basis, and 96.5% (443 of 459) and 87.8% (94 of 107), respectively, on a per-aneurysm basis. Digital subtraction CT angiography had sensitivities of 91.3% (42 of 46), 94.0% (140 of 149), 98.4% (186 of 189), and 100% (75 of 75) in depicting aneurysms of less than 3 mm, between 3 mm but less than 5 mm, between 5 mm but less than 10 mm, and 10 mm or greater, respectively, and of 95.8% (276 of 288) and 97.7% (167 of 171) in depicting anterior circulation and posterior circulation aneurysms, respectively. Excellent inter- and intrareader agreement was found on a per-patient (κ=0.900 and 0.939, both P<.001) and per-aneurysm basis (κ=0.846 and 0.921, both P<.001) for the detection of intracranial aneurysms with digital subtraction CT angiography.

CONCLUSION

Digital subtraction CT angiography has a high sensitivity and specificity in depicting intracranial aneurysms with different sizes and at different locations, compared with 3D DSA.

Applications of multislice CT angiography in the surgical clipping and endovascular coiling of intracranial aneurysms

Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage (SAH). The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography (CTA) in the surgical and endovascular treatment of intracranial aneurysms. A total of 195 cases with 206 intracranial aneurysms underwent CTA. Fifty (24%) aneurysms underwent surgical clipping while 156 (76%) aneurysms underwent endovascular coiling. In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas, surgical treatment was successfully performed based on 16-slice CTA alone, and the other 36 aneurysms were clipped on the main basis of the CTA. The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully. Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.