Subarachnoid hemorrhage without evident cause on initial angiography studies: diagnostic yield of subsequent angiography and other neuroimaging tests

Risk stratification of delayed causative aneurysm detection and long-term outcome in angiographically negative spontaneous subarachnoid haemorrhage

BACKGROUND

The risk factors of aetiology and poor outcome in angiographically negative subarachnoid haemorrhage (anSAH) were unclearly.

METHODS

The authors performed a retrospective review of a prospectively maintained database for anSAH patients between 2014 and 2018. AnSAH was defined as SAH presents in CT with no underlying vascular abnormality on initial digital subtraction angiography (DSA) within 72 hours of admission. Baseline and follow-up information, including medical history, bleeding pattern (perimesencephalic angiogram-negative SAH (PAN-SAH) and non-PAN-negative SAH (NPAN-SAH)), modified Fisher Scale (mFS), Glasgow Coma Score (GCS), Hunt-Hess grade, repeated imaging and causative vascular lesions and follow-up modified Rankin Scale (mRS) were reviewed. Poor outcome was defined as mRS scored 3-6 at last clinical follow-up.

RESULTS

Among 303 enrolled patients, 272 patients underwent at least once repeated imaging examination (median follow-up time, 3.0 months). Twenty-one (7.7%) aneurysms were detected. Multivariate logistic analysis showed that NPAN-SAH and mFS 3-4 were associated with a high rate of aneurysm detection in anSAH patients. Based on risk stratification, the aneurysm detection rate in the high-risk group (both NPAN-SAH and mFS 3-4) was as high as 20.370 per 100 person-years. Furthermore, of 251 non-aneurysm anSAH patients, after a total follow-up time of 1265.83 patient-years, poor outcome occurred in 18 (7.2%) patients. Multivariate Cox analysis found that NPAN-SAH and GCS 3-12 were associated with a high rate of poor outcome of anSAH. The cumulative 5-year incidence rate for poor outcome in the non-aneurysm anSAH patients in the high-risk group (both NPAN-SAH and GCS 3-12) was as high as 75.302 per 100 person-years.

CONCLUSIONS

Even in anSAH confirmed by initial DSA, patients with NPAN-SAH and mFS 3-4 should be monitored for delayed causative aneurysm detection, meanwhile in non-aneurysm anSAH patients, NPAN-SAH and initial functional impairment are associated with poor prognosis.

Susceptibility weighted imaging for ruptured basilar artery perforator aneurysms in the setting of angiographically negative subarachnoid hemorrhage

BACKGROUND

Ruptured basilar artery perforator aneurysms (BAPAs), defined as microaneurysms which develop in basilar perforator arteries without direct involvement of the basilar trunk, represent a rare cause of subarachnoid hemorrhage (SAH). The diagnosis of BAPAs is difficult because of their small size, with high rates of negative angiography. The development of high-resolution MRI could increase the diagnostic performance. In this study we describe the usefulness of susceptibility weighted imaging (SWI) for the diagnosis of ruptured BAPAs.

METHODS

In a case series, we retrospectively collected data of patients admitted to our institution from 2018 to 2021 for SAH with negative CT angiography who underwent MRI (including SWI) and DSA during hospitalization.

RESULTS

Eight patients with a definitive diagnosis of ruptured BAPA and five patients with a definitive diagnosis of angiogram-negative SAH were included. In all of the patients with BAPAs MRI showed a focal, thick, semi-circumferential SWI hypointensity covering the vessel wall at the level of the BAPA subsequently revealed on DSA; this phenomen is known as 'SWI capping'. No SWI capping was observed in the five patients with a definitive diagnosis of angiogram-negative SAH.

CONCLUSION

SWI capping appears to be a reliable indirect sign for the diagnosis and localization of ruptured BAPAs, a rare form of microaneurysm easily misdiagnosed on DSA in initial angiogram-negative SAH.

Delayed appearance of basilar trunk small atypical aneurysms in nontraumatic, initially angiogram-negative subarachnoid hemorrhage: A report of three patients

BACKGROUND

Repeat angiography will identify vascular pathology in approximately 10% of cases following angiogram-negative subarachnoid hemorrhage (anSAH), but small atypical aneurysms of the basilar artery are very uncommon.

OBJECTIVE

To report a case series of delayed appearance of nontraumatic basilar artery small atypical aneurysms.

METHODS

IRB approval was obtained for this retrospective case series and patient consent was waived.

RESULTS

Herein we report three cases of spontaneous anSAH, all of whom had a negative digital subtraction angiogram (DSA) on admission and all of whom had appearance of a small atypical aneurysms of the upper basilar trunk/apex on follow-up imaging (two during the initial admission and one in a delayed fashion). All three patients were ultimately treated with flow diversion (although one patient underwent attempted coiling that was abandoned due to inability to catheterize the aneurysm).

CONCLUSION

This report highlights the importance of a repeat DSA in cases of anSAH as well as the importance of scrutinizing the basilar trunk for these very small atypical aneurysms that may go unnoticed.

A quantitative model to differentiate nonaneurysmal perimesencephalic subarachnoid hemorrhage from aneurysmal etiology

OBJECTIVE

Nonaneurysmal perimesencephalic subarachnoid hemorrhage (pmSAH) is considered to have a lower-risk pattern than other types of subarachnoid hemorrhage (SAH). However, a minority of patients with pmSAH may harbor a causative posterior circulation aneurysm. To exclude this possibility, many institutions pursue exhaustive imaging. In this study the authors aimed to develop a novel predictive model based on initial noncontrast head CT (NCHCT) features to differentiate pmSAH from aneurysmal causes.

METHODS

The authors retrospectively reviewed patients admitted to an academic center for treatment of a suspected aneurysmal SAH (aSAH) during the period from 2016 to 2021. Patients with a final diagnosis of pmSAH or posterior circulation aSAH were included. Using NCHCT, the thickness (continuous variable) and location of blood in basal cisterns and sylvian fissures (categorical variables) were compared between groups. A scoring system was created using features that were significantly different between groups. Receiver operating characteristic curve analysis was used to measure the accuracy of this model in predicting aneurysmal etiology. A separate patient cohort was used for external validation of this model.

RESULTS

Of 420 SAH cases, 48 patients with pmSAH and 37 with posterior circulation aSAH were identified. Blood thickness measurements in the crural and ambient cisterns and interhemispheric and sylvian fissures and degree of extension into the sylvian fissure were all significantly different between groups (all p < 0.001). The authors developed a 10-point scoring model to predict aneurysmal causes with high accuracy (area under the curve [AUC] 0.99; 95% CI 0.98-1.00; OR per point increase 10; 95% CI 2.18-46.4). External validation resulted in persistently high accuracy (AUC 0.97; 95% CI 0.92-1.00) of this model.

CONCLUSIONS

A risk stratification score using initial blood clot burden may accurately differentiate between aneurysmal and nonaneurysmal pmSAH. Larger prospective studies are encouraged to further validate this quantitative tool.

Angiographically Occult Subarachnoid Hemorrhage: Yield of Repeat Angiography, Influence of Initial CT Bleed Pattern, and Sources of Diagnostic Error in 242 Consecutive Patients

BACKGROUND AND PURPOSE

Nearly 20% of patients with spontaneous SAH have no definitive source on initial DSA. The purpose of this study was to investigate the timing and yield of repeat DSA, to clarify the influence of initial CT bleed pattern, and to characterize sources of diagnostic error in this scenario.

MATERIALS AND METHODS

We evaluated the yield of repeat DSA and clinical outcomes stratified by hemorrhage pattern on CT in consecutive patients with nontraumatic SAH with negative initial DSA findings at a referral center. Cases in which the culprit lesion was subsequently diagnosed were classified as physiologically occult (ie, undetectable) on the initial DSA, despite adequate technique and interpretation or misdiagnosed due to operator-dependent error.

RESULTS

Two hundred forty-two of 1163 (20.8%) patients with spontaneous SAH had negative initial DSA findings between 2009 and 2018. The SAH CT pattern was nonperimesencephalic (41%), perimesencephalic (36%), sulcal (18%), and CT-negative (5%). Repeat DSA in 135/242 patients (55.8%) revealed a source in 10 patients (7.4%): 4 saccular aneurysms, 4 atypical aneurysms, and 2 arteriovenous shunts. The overall yield of repeat DSA was 11.3% with nonperimesencephalic and 2.2% for perimesencephalic patterns. The yield of the second and third DSAs with a nonperimesencephalic pattern was 7.7% and 12%, respectively. Physiologically occult lesions accounted for 6/242 (2.5%) and operator-dependent errors accounted for 7/242 (2.9%) of all angiographically occult lesions on the first DSA.

CONCLUSIONS

Atypical aneurysms and small arteriovenous shunts are important causes of SAH negative on angiography. Improving DSAs technique can modestly reduce the need for repeat DSA; however, a small fraction of SAH sources remain occult despite adequate technique. These findings support the practice of repeating DSA in patients with a nonperimesencephalic SAH pattern.

Isolated oculomotor nerve palsy secondary to non-aneurysmal subarachnoid hemorrhage

We present a case series of two patients who developed unilateral cranial nerve III (CNIII) palsy following non-aneurysmal SAH (NASAH). Subarachnoid hemorrhage (SAH) can present with various signs and symptoms. Early diagnosis is paramount to determine treatment course. Thus, clinicians must be aware of the variable clinical presentations of this condition. Two patients were admitted to a single institution for SAH. Patient 1, 52-year-old male, presented with headache, left eye ptosis, and painless diplopia. A non-contrast head computed tomography (CT) demonstrated a SAH within the left sylvian fissure and blood surrounding the mesencephalon and falx. Patient 2, 70-year-old male, presented with mild headache, acute onset of blurry vision, and right eye ptosis. A non-contrast head CT demonstrated a diffuse SAH predominantly in the Sylvian and suprasellar cisterns. Patients were admitted to the neuro intensive care unit and underwent diagnostic angiograms to identify possible aneurysms. Magnetic resonance imaging and angiograms for both patients were negative. Patients were managed with best medical therapy and followed up in the outpatient setting. Unilateral CNIII palsy in the setting of NASAH was identified in both patients. Diagnostic angiograms were negative for aneurysms; therefore, SAH were determined to be spontaneous. We propose that unilateral CNIII palsy is a possible sign of NASAH.

Factors determining outcome of post-angiogram-negative subarachnoid hemorrhage

Aim:

To determine the risk factors affecting outcome at the end of 90 days of post-angiogram-negative subarachnoid hemorrhage (SAH).

Methods:

Non-traumatic SAH cases were reviewed from the case records of patients who had reported to the Department of Neurology of a tertiary care hospital and 50 angio-negative SAH cases were included after excluding all the cases with known cause of hemorrhage after doing computed tomography angiography (CTA)/digital subtraction angiography (DSA). The presence of hypertension, diabetes mellitus, coronary artery disease (CAD), history of alcohol and smoking, and various scales like Hunt and Hess Scale (HHS), World Federation of Neurological Surgeons (WFNS), and Fisher scale had been recorded at admission. The outcome was assessed at 90 days post-SAH using the Modified Rankin Scale (mRS).

Statistical analyses:

The association between the outcome and the factors was assessed using the Pearson Chi-Square test and the risk factors/predictors of outcome were assessed using logistic regression.

Results:

The following variables were important risk factors for predicting poor outcome of angio-negative SAH (mRS 3 to 6): hypertension (P = 0.011), diabetes mellitus (P = 0.032), being an alcoholic (P = 0.019), HHS grade 4 to 5 (P < 0.01), and WFNS grade 4 to 5 (P < 0.01). On multivariate regression analysis, hypertension (P = 0.032) was an independent predictor of unfavorable outcome.

Conclusions:

At time of admission, presence of hypertension, diabetes mellitus, history of alcohol consumption, and poor grades of HHS and WFNS scale are predictors of poor outcome of angio-negative SAH.

Repeat Catheter Angiography in Patients with Aneurysmal-Pattern Angiographically Negative Subarachnoid Hemorrhage

BACKGROUND

A significant proportion of patients with subarachnoid hemorrhage have a normal cerebral angiogram. Patients with angiographically negative subarachnoid hemorrhage (anSAH) with either perimesencephalic- (panSAH) or aneurysmal-pattern hemorrhage (aanSAH, also known as diffuse anSAH) have an excellent prognosis, but only if underlying vascular abnormalities are completely excluded. The rate of occult aneurysms in patients with aanSAH varies widely across studies. The purpose of this study was to quantify the value of repeat DSA in these patients.

METHODS

We reviewed the records of all patients initially diagnosed with aanSAH after a screening DSA at a single tertiary neurovascular referral center from January 2006-April 2018. Patients with panSAH and traumatic SAH were excluded. We also performed a systematic review and meta-analysis of positive second DSAs in previously published case series of patients with aanSAH who underwent two serial DSAs. For meta-analysis, PubMed Central, MEDLINE and Cochrane Library databases were searched for pertinent studies up to November 2019. The rate of aneurysm detection on repeat angiography was extracted from each study. Pooled rates for positive second angiogram were calculated as untransformed proportions in a binary random-effects model meta-analysis. Inter-study heterogeneity was calculated using an I² statistic.

RESULTS

Three of 27 patients (11.1%) with aanSAH and at least two DSAs were subsequently found to have a cerebral aneurysm in our institutional dataset. Twenty-six studies in our systematic review met inclusion criteria, and the pooled rate of positive second angiogram was 10.4% (95% CI 7.3%-13.5%, P < 0.001). Substantial inter-study heterogeneity was observed in the meta-analysis (I² = 61.7%, P < 0.001).

CONCLUSIONS

One in 10 patients with aanSAH has an occult ruptured aneurysm. A second-look DSA should be strongly considered in these cases.

Nontraumatic Nonaneurysmal Subarachnoid Hemorrhage: Risk Factors, Complications, and Clinical Outcomes

Background The present study aimed to investigate the risk factors, complications, and clinical outcomes of patients with nontraumatic, nonaneurysmal subarachnoid hemorrhage (NNSAH).

Methods We retrospectively evaluated 78 consecutive patients with NNSAH admitted to our center between April 2009 and April 2019. Patients were divided into two groups based on the distribution of blood in the CT scan, perimesencephalic subarachnoid hemorrhage ( PM-SAH) and nonperimesencephalic subarachnoid hemorrhage (nPM-SAH) groups. The outcome was assessed according to the Glasgow outcome scale (GOS). The demographic data and clinical records including age, sex, smoking history, hypertension, diabetes, history of anticoagulant medication, Glasgow coma score (GCS), Hunt–Hess (HH) grades, and in-hospital complications and clinical outcomes were retrospectively reviewed and compared between the two groups.

Results There were 45 patients (57.69%) in the PM-SAH group and 33 cases (42.30%) in the nPM-SAH group with the mean age of 53.98 ± 7.7 years. There were no significant differences between the two groups based on age, sex, smoking history, diabetes, hypertension, anticoagulation medication history, and HH grade at admission. The nPM-SAH group was significantly associated with a higher incidence of radiological and clinical vasospasm (p < 0.05). Moreover, the need for external ventricular drainage (EVD) placement because of the development of hydrocephalus was significantly higher in the nPM group (p < 0.05). Patients with PM-SAH had better clinical outcomes than those with nPM-SAH (p = 0.037).

Conclusions Our results showed that patients with nonaneurysmal subarachnoid hemorrhage (NSAH) had favorable clinical outcomes. The PM group had better clinical outcomes and lower complication rates in comparison with the nPM group. Repeated digital subtraction angiography (DSA) examinations are strongly recommended for patients with nPM-SAH.

AH, R. PA. The Yield of Repeat Angiography in Angiography-Negative Spontaneous Subarachnoid Hemorrhage

Objective  Despite the technological advancement in imaging, digital subtraction angiography (DSA) remains gold standard imaging modality for spontaneous subarachnoid hemorrhage (SAH). But even after DSA, around 15% of SAH remains elusive for the cause of the bleed. This is an institutional review to solve the mystery, “when is second DSA really indicated?”

Methods  In a retrospective review from January 2015 to December 2017, we evaluated cases of spontaneous SAH with initial negative DSA with repeat DSA after 6 weeks to rule out vascular abnormality. The spontaneous SAH was confirmed on noncontrast computed tomography (NCCT) and divided into two groups of perimesencephalic SAH (PM-SAH) or nonperimesencephalic SAH (nPM-SAH). The outcome was assessed by a modified Rankin’s score (mRS) at 6 months postictus.

Results  During the study period, we had 119 cases of initial negative DSA and 98 cases (82.3%) underwent repeat DSA after 6 weeks interval. A total of 53 cases (54.1%) had PM-SAH and 45 cases (45.9%) had nPM-SAH. Repeat DSA after 6 weeks showed no vascular abnormality in 53 cases of PM-SAH and in 2 (4.4%) out of 45 cases of nPM-SAH. At 6 months postictus, all cases of PM-SAH and 93% of nPM-SAH had mRS of 0.

Conclusion  We recommend, a repeat DSA is definitely not required in PM-SAH, but it should be done for all cases of nPM-SAH, before labeling them as nonaneurysmal SAH. Although the overall outcome for nonaneurysmal spontaneous SAH is better than aneurysmal SAH, nPM-SAH has poorer eventual outcome compared to PM-SAH.

Subarachnoid haemorrhage with negative initial neurovascular imaging: a systematic review and meta-analysis

Background

In patients with spontaneous subarachnoid haemorrhage (SAH), a vascular cause for the bleed is not always found on initial investigations. This study aimed to systematically evaluate the delayed investigation strategies and clinical outcomes in these cases, often described as “non-aneurysmal” SAH (naSAH).

Methods

A systematic review was performed in concordance with the PRISMA checklist. Pooled proportions of primary outcome measures were estimated using a random-effects model.

Results

Fifty-eight studies were included (4473 patients). The cohort was split into perimesencephalic naSAH (PnaSAH) (49.9%), non-PnaSAH (44.7%) and radiologically negative SAH identified on lumbar puncture (5.4%). The commonest initial vascular imaging modality was digital subtraction angiography. A vascular abnormality was identified during delayed investigation in 3.9% [95% CI 1.9–6.6]. There was no uniform strategy for the timing or modality of delayed investigations. The pooled proportion of a favourable modified Rankin scale outcome (0–2) at 3–6 months following diagnosis was 92.0% [95% CI 86.0–96.5]. Complications included re-bleeding (3.1% [95% CI 1.5–5.2]), hydrocephalus (16.0% [95% CI 11.2–21.4]), vasospasm (9.6% [95% CI 6.5–13.3]) and seizure (3.5% [95% CI 1.7–5.8]). Stratified by bleeding pattern, we demonstrate a higher rate of delayed diagnoses (13.6% [95% CI 7.4–21.3]), lower proportion of favourable functional outcome (87.2% [95% CI 80.1–92.9]) and higher risk of complications for non-PnaSAH patients.

Conclusion

This study highlights the heterogeneity in delayed investigations and outcomes for patients with naSAH, which may be influenced by the initial pattern of bleeding. Further multi-centre prospective studies are required to clarify optimal tailored management strategies for this heterogeneous group of patients.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-04025-w) contains supplementary material, which is available to authorized users.

Delayed Cerebral Ischemia and Vasospasm After Spontaneous Angiogram-Negative Subarachnoid Hemorrhage: An Updated Meta-Analysis

OBJECTIVE

To report clinical outcomes of delayed cerebral ischemia (DCI) and vasospasm in angiogram-negative subarachnoid hemorrhage (SAH) according to hemorrhage patterns, perimesencephalic hemorrhage (PMH) and non-PMH.

METHODS

Online databases from January 1990 to December 2017 were systematically reviewed. A fixed-effects model was used to control heterogeneity. To resolve publication bias, the trim and fill method was used to estimate number of missing studies and adjusted odds ratio (OR). Subgroup analysis of data from studies that defined angiogram-negative subarachnoid hemorrhage by angiography repeated at least twice or computed tomography angiography was performed.

RESULTS

Among 24 studies including 2083 patients, 23/985 patients (2.3%) with PMH and 144/1098 patients (13.1%) with non-PMH had DCI, indicating that patients with PMH experienced significantly lower DCI than patients with non-PMH (OR = 0.219; 95% confidence interval [CI], 0.144-0.334). Regarding vasospasm, 99/773 patients (12.8%) with PMH and 231/922 patients (25.1%) with non-PMH exhibited vasospasm, indicating that patients with PMH experienced significantly lower vasospasm than patients with non-PMH (OR = 0.445; 95% CI, 0.337-0.589). Funnel plots show asymmetry indicating possible publication bias. After trimming 10 studies for DCI and 7 for vasospasm, the adjusted ORs remained significant between PMH and lower risks of DCI and vasospasm. Subgroup analysis of 789 patients in 8 studies showed a lower risk of DCI (OR = 0.268; 95% CI, 0.151-0.473) and vasospasm (OR = 0.346; 95% CI, 0.221-0.538) in patients with PMH.

CONCLUSIONS

PMH showed a significantly lower risk of DCI and vasospasm than non-PMH. Clinical outcomes of angiogram-negative subarachnoid hemorrhage, based on meta-analysis of individual patient data, need to be investigated.

Non-aneurysmal subarachnoid hemorrhage: When is a second angiography indicated?

Purpose Repeat imaging in patients with non-aneurysmal subarachnoid hemorrhage (NASAH) remains controversial. We aim to report our experience with NASAH with different hemorrhage patterns, and to investigate the need for further diagnostic workup to determine the underlying cause of hemorrhage. Method We conducted a retrospective analysis of all spontaneous SAH with an initial negative computed tomography (CT) with angiography (CTA) and/or digital subtraction angiography (DSA) from October 2011 through May 2017. According to the bleeding pattern on the admission CT scan, NASAH was divided into two subgroups: (1) perimesencephalic SAH (PMSAH) and (2) non-perimesencephalic SAH (nPMSAH). Radiological data included the admission CT, CTA, DSA, and magnetic resonance imaging (MRI) with angiography (MRA). Results Seventy-four patients met the inclusion criteria. Thirty-nine (52.7%) patients had PMSAH on the initial CT scan, and 35 (47.3%) had nPMSAH. All underwent CTA and/or DSA revealing no vascular abnormalities. Forty-seven (63.5%) patients underwent subsequent diagnostic workup. DSA was performed in all patients at least once. No abnormalities were found on the repeat DSA or other radiological follow-up studies except in one (1.4%) patient with nPMSAH, in whom a follow-up DSA revealed a small saccular anterior choroidal artery aneurysm, considered to be the source of hemorrhage. Conclusion A repeat DSA may not be needed in case of PMSAH, if the initial negative DSA is technically adequate with absence of hematoma and vasospasm. In contrast, a follow-up DSA should be mandatory for confirming or excluding vascular pathology in case of nPMSAH in order to prevent rebleeding.

Is there added value in obtaining cervical spine MRI in the assessment of nontraumatic angiographically negative subarachnoid hemorrhage? A retrospective study and meta-analysis of the literature

OBJECTIVE Diagnostic algorithms for nontraumatic angiographically negative subarachnoid hemorrhage (AN-SAH) vary, and the optimal method remains subject to debate. This study assessed the added value of cervical spine MRI in identifying a cause for nontraumatic AN-SAH. METHODS Consecutive patients 18 years of age or older who presented with nontraumatic SAH between February 1, 2009, and October 31, 2014, with negative cerebrovascular catheter angiography and subsequent cervical MRI were studied. Patients with intraparenchymal, subdural, or epidural hemorrhage; recent trauma; or known vascular malformations were excluded. All cervical MR images were reviewed by two blinded neuroradiologists. The diagnostic yield of cervical MRI was calculated. A literature review was conducted to identify studies reporting the diagnostic yield of cervical MRI in patients with AN-SAH. The weighted pooled estimate of diagnostic yield of cervical MRI was calculated. RESULTS For all 240 patients (mean age 53 years, 48% male), catheter angiography was performed within 4 days after admission (median 12 hours, interquartile range [IQR] 10 hours). Cervical MRI was performed within 19 days of admission (median 24 hours, IQR 10 hours). In a single patient, cervical MRI identified a source for SAH (cervical vascular malformation). Meta-analysis of 7 studies comprising 538 patients with AN-SAH produced a pooled estimate of 1.3% (95% confidence interval 0.5%-2.5%) for diagnostic yield of cervical MRI. No statistically significant between-study heterogeneity or publication bias was identified. CONCLUSIONS Cervical MRI following AN-SAH, in the absence of findings to suggest spinal etiology, has a very low diagnostic yield and is not routinely necessary.

Cerebral Vasospasm-Dependent and Cerebral Vasospasm-Independent Cerebral Infarctions Predict Outcome After Nonaneurysmal Subarachnoid Hemorrhage: A Single-Center Series with 250 Patients

OBJECTIVE

The number of patients with nonaneurysmal subarachnoid hemorrhage (naSAH) has increased during the last decade. Data regarding infarctions in naSAH are still limited. The aim of this study was to identify the rate of cerebral vasospasm (CVS)-dependent and CVS-independent infarctions and their influence on clinical outcomes.

METHODS

Between 1999 and 2015, 250 patients suffering from naSAH were analyzed retrospectively. A delayed infarction was analyzed whether it was associated with CVS (CVS-dependent infarction) or not (CVS-independent).

RESULTS

A total of 36 patients (14%) had cerebral infarctions. CVS was detected in 54 patients (22%), and 15 (6%) of them developed infarctions (CVS-dependent). Infarctions without signs of CVS (CVS-independent) occurred in 21 patients (8%). Overall, 86% of the patients had favorable outcome. Patients without cerebral infarctions had the best outcome (91% favorable outcome, 5% mortality rate). Patients with CVS-independent infarctions (57%) as well as patients with CVS-dependent infarctions (53%) had a favorable outcome less often. The mortality rate was also significantly greater in patients with CVS-independent (19%) and CVS-dependent infarctions (33%). A further independent predictor was anticoagulative therapy, which increased during study period and was associated with nonperimesencephalic blood distribution.

CONCLUSIONS

CVS-dependent and independent infarctions occur in naSAH and contribute to unfavorable outcomes. Whereas CVS-independent infarctions occur in any subgroup, CVS-dependent infarctions seem to be associated with blood pattern (Fisher 3). Anticoagulative therapy seems to be not only a predictor for worse outcome but also for nonperimesencephalic SAH. Accordingly, the proportion of perimesencephalic and nonperimesencephalic SAH changed during the study period (from 2.2:1 to 1:1.7).

Management of Spontaneous Subarachnoid Hemorrhage Patients with Negative Initial Digital Subtraction Angiogram Findings: Conservative or Aggressive?

Background. The ideal management of SAH patients with negative initial DSA findings remains unresolved. Objective. (i) To present risk factors, clinical courses, and outcomes in different types of SAH patients with negative DSA findings; (ii) to explore the differences of basal vein between aSAH patients and NASAH patients; and (iii) to evaluate the value of repeated DSA for these patients. Methods. All SAH patients with negative initial DSA findings between 2013 and 2015 in our hospital were enrolled and were further categorized as perimesencephalic SAH (PMN-SAH) or nonperimesencephalic SAH (nPMN-SAH). Risk factors, clinical courses, outcomes, and the basal vein drainage patterns were compared. Results. A total of 137 patients were enrolled in the present study. The PMN-SAH group had better GOS and mRS values at 1-year follow-up. Moreover, the nPMN-SAH group had a higher rate of complications. The basal vein drainage pattern showed significant difference when comparing each of the NASAH subtypes with aSAH groups. There was a significant higher rate of a responsible aneurysm in nPMN-SAH group upon repeated DSA. Conclusions. SAH patients with negative initial DSA findings had benign clinical courses and outcomes. Repeated DSA studies are strongly advised for patients with the nPMN-SAH pattern.

Patients with Blunt Traumatic Brain Injury: A Role for Computed Tomography Angiography of the Head to Evaluate Nontraumatic Causes?

BACKGROUND

In the setting of trauma, the cause of intracranial hemorrhage (ICH) is frequently attributed to the physical, traumatic event. Caution should still be directed toward nontraumatic (or spontaneous) causes responsible for the trauma, such as hypertension, cerebral amyloid angiopathy, aneurysms, vascular malformation, and hemorrhagic infarcts. The role for immediate computed tomography angiography remains controversial to evaluate for nontraumatic causes.

METHODS

A systematic review of the available literature in the Medline PubMed database.

RESULTS

In the available literature, only 12 patients with traumatic brain injury underwent computed tomography angiography of the head that either showed a vascular malformation and/or altered clinical management because of concerns of a vascular malformation. The ICH in 11 patients was attributed to rupture of a cerebral aneurysm; the other patient received a diagnostic angiogram that was negative.

CONCLUSIONS

ICH in patients with traumatic brain injury seems to be vastly associated with the traumatic event. Only rare cases have been attributed to aneurysmal rupture. None has been associated with arteriovenous malformation. Nevertheless, clinical vigilance remains reasonable, especially in younger patients and those with hemorrhage within the subarachnoid cisterns or sylvian fissure.

Yield of Repeat 3D Angiography in Patients with Aneurysmal-Type Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Aneurysmal-type subarachnoid hemorrhage is a serious disease with high morbidity and mortality. When no aneurysm is found, the patient remains at risk for rebleeding. Negative findings for SAH on angiography range from 2% to 24%. Most previous studies were based on conventional 2D imaging. 3D rotational angiography depicts more aneurysms than 2D angiography. The purpose of this study was to evaluate the yield of repeat 3D rotational angiography in patients with aneurysmal-type SAH with negative initial 3D rotational angiography findings and to classify the initial occult aneurysms.

MATERIALS AND METHODS

Between March 2013 and January 2016, 292 patients with SAH and an aneurysmal bleeding pattern were admitted. Of these 292 patients, 30 (10.3%; 95% CI, 7.3%-14.3%) had initial negative 3D rotational angiography findings within 24 hours. These patients underwent a second 3D rotational angiography after 7-10 days.

RESULTS

In 8 of 30 patients (26.7%; 95% CI, 14.0%-44.7%) with initial negative 3D rotational angiography findings, a ruptured aneurysm was found on repeat 3D rotational angiography. Three of 8 initial occult aneurysms were very small (1-2 mm), 2 were supraclinoid carotid artery dissecting aneurysms (2 and 8 mm), 2 were small (1 and 3 mm) basilar perforator aneurysms, and 1 was a 3-mm vertebral artery dissecting aneurysm.

CONCLUSIONS

In 10% of patients with aneurysmal-type SAH, initial 3D rotational angiography findings were negative, and in 1 in 4, repeat 3D rotational angiography demonstrated a ruptured aneurysm. Initial occult aneurysms were dissecting aneurysms of perforators or main arteries or were very small (1-2 mm) or both. Our results indicate that repeat 3D rotational angiography is mandatory in patients with initial 3D rotational angiography findings negative for aneurysmal-type SAH.

Spontaneous Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis Describing the Diagnostic Accuracy of History, Physical Examination, Imaging, and Lumbar Puncture With an Exploration of Test Thresholds

BACKGROUND

Spontaneous subarachnoid hemorrhage (SAH) is a rare, but serious etiology of headache. The diagnosis of SAH is especially challenging in alert, neurologically intact patients, as missed or delayed diagnosis can be catastrophic.

OBJECTIVES

The objective was to perform a diagnostic accuracy systematic review and meta-analysis of history, physical examination, cerebrospinal fluid (CSF) tests, computed tomography (CT), and clinical decision rules for spontaneous SAH. A secondary objective was to delineate probability of disease thresholds for imaging and lumbar puncture (LP).

METHODS

PubMed, Embase, Scopus, and research meeting abstracts were searched up to June 2015 for studies of emergency department patients with acute headache clinically concerning for spontaneous SAH. QUADAS-2 was used to assess study quality and, when appropriate, meta-analysis was conducted using random effects models. Outcomes were sensitivity, specificity, and positive (LR+) and negative (LR-) likelihood ratios. To identify test and treatment thresholds, we employed the Pauker-Kassirer method with Bernstein test indication curves using the summary estimates of diagnostic accuracy.

RESULTS

A total of 5,022 publications were identified, of which 122 underwent full-text review; 22 studies were included (average SAH prevalence = 7.5%). Diagnostic studies differed in assessment of history and physical examination findings, CT technology, analytical techniques used to identify xanthochromia, and criterion standards for SAH. Study quality by QUADAS-2 was variable; however, most had a relatively low risk of biases. A history of neck pain (LR+ = 4.1; 95% confidence interval [CI] = 2.2 to 7.6) and neck stiffness on physical examination (LR+ = 6.6; 95% CI = 4.0 to 11.0) were the individual findings most strongly associated with SAH. Combinations of findings may rule out SAH, yet promising clinical decision rules await external validation. Noncontrast cranial CT within 6 hours of headache onset accurately ruled in (LR+ = 230; 95% CI = 6 to 8,700) and ruled out SAH (LR- = 0.01; 95% CI = 0 to 0.04); CT beyond 6 hours had a LR- of 0.07 (95% CI = 0.01 to 0.61). CSF analyses had lower diagnostic accuracy, whether using red blood cell (RBC) count or xanthochromia. At a threshold RBC count of 1,000 × 10(6) /L, the LR+ was 5.7 (95% CI = 1.4 to 23) and LR- was 0.21 (95% CI = 0.03 to 1.7). Using the pooled estimates of diagnostic accuracy and testing risks and benefits, we estimate that LP only benefits CT-negative patients when the pre-LP probability of SAH is on the order of 5%, which corresponds to a pre-CT probability greater than 20%.

CONCLUSIONS

Less than one in 10 headache patients concerning for SAH are ultimately diagnosed with SAH in recent studies. While certain symptoms and signs increase or decrease the likelihood of SAH, no single characteristic is sufficient to rule in or rule out SAH. Within 6 hours of symptom onset, noncontrast cranial CT is highly accurate, while a negative CT beyond 6 hours substantially reduces the likelihood of SAH. LP appears to benefit relatively few patients within a narrow pretest probability range. With improvements in CT technology and an expanding body of evidence, test thresholds for LP may become more precise, obviating the need for a post-CT LP in more acute headache patients. Existing SAH clinical decision rules await external validation, but offer the potential to identify subsets most likely to benefit from post-CT LP, angiography, or no further testing.

Should Patients Be Counseled About Possible Recurrence of Perimesencephalic Subarachnoid Hemorrhage?

BACKGROUND

Isolated perimesencephalic subarachnoid hemorrhage (pSAH) is a distinct subtype of subarachnoid hemorrhage (SAH) seen in 5% of patients with SAH, with a relatively benign natural course and good outcome compared with diffuse, aneurysmal SAH. Traditionally, the prognosis of pSAH is believed to be excellent compared with aneurysmal SAH, with no risk of recurrent hemorrhage after long-term follow-up. We describe a case of pSAH in which the patient had a recurrent perimesencephalic bleed 8 years after the initial episode. There are 5 previous reports of recurrent pSAH in existing literature.

CASE REPORT

A patient in sixth decade of life with no history of trauma presented in 2006 with acute-onset, severe headache, and "off-balance" gait. The patient was diagnosed with pSAH on the basis of computed tomography angiography and digital subtraction angiography. The patient was discharged, and follow-up computed tomography angiography over the next 2 years revealed no underlying vascular anomaly. The patient presented in 2014 with sudden onset of headache, similar to the previous episode with no new neurologic signs. Patient had repeated imaging over the succeeding 2 years, which were all negative for new blood or source of subarachnoid bleed.

REVIEW AND DISCUSSION

There are only a couple of case reports of recurrent pSAH, some of which were defined questionably. We review the reported cases and discuss the imaging results and outcome. Considering the rarity, low risks of complications, as well as the good outcome even after recurrence, we do not recommend routinely counseling patients about possibility of recurrence of pSAH.

Short- and long-term outcomes in non-aneurysmal non-perimesencephalic subarachnoid hemorrhage

OBJECTIVE

Our aim was to assess the short- and long-term prognosis in patients suffering from non-aneurysmal non-perimesencephalic SAH (Na-NPM-SAH).

METHODS

Based on admission CT-scan, SAH was categorized as perimesencephalic (PM) or non-perimesencephalic (NPM). Based on digital subtraction angiography (DSA) results, patients were classified as normal DSA (Na-SAH) or aneurysmal SAH (aSAH). Between 1997 and 2010, 67 of 571 patients with non-traumatic SAH (11.7%) suffered from non-aneurysmal non-perimesencephalic SAH. Retrospective analyses of the 67 patients were undertaken, and compared with the aneurysmal SAH group. Long-term follow-up was assessed.

RESULTS

The cohort consisted of 67 Na-NPM-SAH patients, mean age 54.8 years (range: 21-84), 56.7% male. Acute phase: 10.4% mortality and 3% rebleeding (two patients) during the acute phase. Long-term: extensive follow-up was possible in all except one of the survivors at discharge. Mortality was 6.6% during the 510 patient-years follow-up period (median follow-up time per patient, 8.95 years); rebleeding rate was 0-1.6%. An aneurysmal source was found in 13% of patients who underwent a second angiography. Aneurysmal SAH: 312 patients, with confirmed aneurysm by angiography. The mortality rate for Na-NPM-SAH during the acute phase was 10.4%, vs. 20% for aneurysmal SAH in the general database, p = 0.049.

DISCUSSION

Na-NPM-SAH patients without an identifiable bleeding source on initial angiography might have a more benign short- and long-term prognosis than aneurysmal SAH patients. Our study confirms an important diagnostic advantage of a second arteriography. Still, despite the major concern of an undetected aneurysm, the long-term rebleeding rate was low in this subgroup of patients.

High-Resolution Vessel Wall Magnetic Resonance Imaging in Angiogram-Negative Non-Perimesencephalic Subarachnoid Hemorrhage

PURPOSE

Standard magnetic resonance imaging (MRI) rarely identifies the cause of hemorrhage in patients with an angiogram-negative, non-perimesencephalic subarachnoid hemorrhage (SAH). Yet up to 10 % of these patients have recurrent hemorrhage. The aim of the study was to explore the potential role of high-resolution contrast-enhanced 3-Tesla vessel wall-MRI in patients with angiogram-negative SAH.

METHODS

We performed intracranial vessel wall-MRI of the circle of Willis using a 3-Tesla scanner in consecutive patients presenting with a spontaneous, angiogram-negative, non-perimesencephalic SAH. Vessel wall-MRI included T1-, T2-, and gadolinium-enhanced T1-weighted two-dimensional black-blood sequences in multiple planes (voxel size 0.4 × 0.4 × 2.0 mm). Two neuroradiologists independently scored abnormalities of the arterial wall.

RESULTS

In all, 11 patients (mean age 59 years) underwent vessel wall-MRI. A total of seven patients had vessel wall abnormalities despite normal catheter angiography. Two patients had focal abnormalities contiguous with the outer margin of the basilar artery wall for which we considered a differential of ruptured blood blister aneurysm, thrombosed aneurysm, and loculated extramural blood from elsewhere. Two patients had arterial wall enhancement involving multiple arteries, possibly secondary to SAH. Three patients had arterial wall enhancement at sites of dural penetration, remote from the SAH, likely related to age and atherosclerotic risk factors. Vessel wall-MRI did not alter patient management in this cohort.

CONCLUSION

Vessel wall-MRI showed abnormalities in seven patients with angiogram-negative SAH. These findings did not alter patient management, but the findings may be useful for other physicians who choose to perform vessel wall-MRI in this patient population.

A completely thrombosed, nongiant middle cerebral artery aneurysm mimicking an intra-axial neoplasm

Background:

Few reports exist regarding thrombosed aneurysms where the initial work up was concerning for a neoplasm. To date, no published reports exist regarding a nongiant thrombosed middle cerebral artery aneurysm, where the primary workup and treatment plan was directed toward a preliminary diagnosis of intra-axial neoplasm.

Case Description:

We report a 43-year-old female who presented with a generalized tonic-clonic seizure attributed to a lesion along the right superior temporal gyrus. The lesion enhanced on initial magnetic resonance imaging (MRI) of the brain, as well as on follow-up MRI. Subsequent vascular studies and metastatic work up were negative. A craniotomy with image guidance was performed and an intraoperative diagnosis was made of a thrombosed aneurysm along a branch of the middle cerebral artery. The aneurysm was trapped and resected as there was no significant flow from the branch as seen on the prior cerebral angiogram. The patient had an uneventful postoperative course.

Conclusion:

Completely thrombosed, nongiant aneurysms can mimic an intra-axial neoplasm. Typical imaging features for thrombosed aneurysms may be missed, especially if the aneurysms are small, where imaging characteristics of the intraluminal contents is more difficult to appreciate. Although imaging may be consistent with a neoplastic lesion, there should be suspicion for a potential underlying aneurysm.

Cerebral Angiography for Evaluation of Patients with CT Angiogram-Negative Subarachnoid Hemorrhage: An 11-Year Experience

BACKGROUND AND PURPOSE

CT angiography is increasingly used to evaluate patients with nontraumatic subarachnoid hemorrhage given its high sensitivity for aneurysms. We investigated the yield of digital subtraction angiography among patients with SAH or intraventricular hemorrhage and a negative CTA.

MATERIALS AND METHODS

An 11-year, single-center retrospective review of all consecutive patients with CTA-negative SAH was performed. Noncontrast head CT, CTA, DSA, and MR imaging studies were reviewed by 2 experienced interventional neuroradiologists and 1 neuroradiologist.

RESULTS

Two hundred thirty patients (mean age, 54 years; 51% male) with CTA-negative SAH were identified. The pattern of SAH was diffuse (40%), perimesencephalic (31%), sulcal (31%), isolated IVH (6%), or identified by xanthochromia (7%). Initial DSA yield was 13%, including vasculitis/vasculopathy (7%), aneurysm (5%), arteriovenous malformation (0.5%), and dural arteriovenous fistula (0.5%). An additional 6 aneurysms/pseudoaneurysms (4%) were identified by follow-up DSA, and a single cavernous malformation (0.4%) was identified by MRI. No cause of hemorrhage was identified in any patient presenting with isolated intraventricular hemorrhage or xanthochromia. Diffuse SAH was due to aneurysm rupture (17%); perimesencephalic SAH was due to aneurysm rupture (3%) or vasculitis/vasculopathy (1.5%); and sulcal SAH was due to vasculitis/vasculopathy (32%), arteriovenous malformation (3%), or dural arteriovenous fistula (3%).

CONCLUSIONS

DSA identifies vascular pathology in 13% of patients with CTA-negative SAH. Aneurysms or pseudoaneurysms are identified in an additional 4% of patients by repeat DSA following an initially negative DSA. All patients with CT-negative SAH should be considered for DSA. The pattern of SAH may suggest the cause of hemorrhage, and aneurysms should specifically be sought with diffuse or perimesencephalic SAH.

Recurrent Perimesencephalic Subarachnoid Hemorrhage After 12 Years: Missed Diagnosis, Vulnerable Anatomy, or Random Events?

BACKGROUND

Perimesencephalic subarachnoid hemorrhage (PMSAH) is a well-defined subtype of angiogram-negative SAH, characterized by a benign natural history and a virtually nonexistent risk of recurrence. Few case reports of recurrent PMSAH exist in the literature, all occurring after relatively short time intervals ranging from 5 days to 31 months, mostly in patients on antithrombotic therapy. We present a unique case of ultra-late PMSAH recurrence after 12 years, in a patient not receiving antithrombotic medications.

CASE DESCRIPTION

A woman presented with 2 similar episodes of sudden-onset severe headache and neck pain, without associated neurologic deficits: a first episode at the age of 48 years and a second at 60 years. In each instance, the pattern of hemorrhage was consistent with PMSAH, platelet count and coagulation tests were normal, and a full etiologic work-up, including CTA, catheter angiography, and magnetic resonance imaging, failed to reveal an underlying vascular or tumoral etiology. The patient had a favorable clinical course each time.

CONCLUSIONS

Although exceptional, recurrence of PMSAH is not impossible. If the 2 events are assumed to be random and independent of each other, binomial statistics yield approximately a 79 per billion chance of 2 or more episodes occurring over an 80-year lifetime. However, other possibilities should be kept in mind, including tiny and radiographically occult vascular lesions or particular venous anatomy predisposing patients to recurrent bouts of PMSAH. Patients should not be told that the risk of recurrence is zero, but that it is close to zero.

Use of Follow-Up Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Background and Purpose—

Multiple studies have shown that negative computed tomographic angiograms (CTAs) are reliable in excluding aneurysms in patients with isolated perimesencephalic subarachnoid hemorrhage (pSAH). We evaluate the use of digital subtraction angiography versus CTA for initial diagnosis and of angiographic follow-ups in patients with pSAH by performing an institutional analysis and a meta-analysis of literature.

Methods—

Retrospective institutional analysis of patients with pSAH was performed from 2008 to 2014. The number and types of follow-up imaging studies were tabulated. Initial and follow-up studies were evaluated by an experienced neuroradiologist for intracranial aneurysm. Meta-analysis of literature was performed to assess the use of initial digital subtraction angiography and of follow-up imaging.

Results—

Our institutional review revealed no additional use of initial digital subtraction angiography or of any angiographic follow-up after initial negative CTA in patients with pSAH on noncontrast CT. Meta-analysis of 40 studies yielded a total of 1031 patients. Only 8 aneurysms were first diagnosed on follow-ups (0.78%). Careful review showed that some of these aneurysms reported on follow-up are of questionable validity. Initial digital subtraction angiography and follow-up imaging after a negative initial CTA showed no statistically significant benefits.

Conclusions—

In patients meeting the strict imaging criteria of pSAH, initial negative CTA is reliable in excluding aneurysms. A critical review of the literature through meta-analysis shows no foundation for multiple follow-up studies in patients with pSAH.

Spontaneous subarachnoid hemorrhage of unknown origin: hospital course and long-term clinical and angiographic follow-up

OBJECT

Hemorrhagic origin is unidentifiable in 10%-20% of patients presenting with spontaneous subarachnoid hemorrhage (SAH). While the patients in such cases do well clinically, there is a lack of long-term angiographic followup. The authors of the present study evaluated the long-term clinical and angiographic follow-up of a patient cohort with SAH of unknown origin that had been enrolled in the Barrow Ruptured Aneurysm Trial (BRAT).

METHODS

The BRAT database was searched for patients with SAH of unknown origin despite having undergone two or more angiographic studies as well as MRI of the brain and cervical spine. Follow-up was available at 6 months and 1 and 3 years after treatment. Analysis included demographic details, clinical outcome (Glasgow Outcome Scale, modified Rankin Scale [mRS]), and repeat vascular imaging.

RESULTS

Subarachnoid hemorrhage of unknown etiology was identified in 57 (11.9%) of the 472 patients enrolled in the BRAT study between March 2003 and January 2007. The mean age for this group was 51 years, and 40 members (70%) of the group were female. Sixteen of 56 patients (28.6%) required placement of an external ventricular drain for hydrocephalus, and 4 of these subsequently required a ventriculoperitoneal shunt. Delayed cerebral ischemia occurred in 4 patients (7%), leading to stroke in one of them. There were no rebleeding events. Eleven patients were lost to followup, and one patient died of unrelated causes. At the 3-year follow-up, 4 (9.1%) of 44 patients had a poor outcome (mRS > 2), and neurovascular imaging, which was available in 33 patients, was negative.

CONCLUSIONS

Hydrocephalus and delayed cerebral ischemia, while infrequent, do occur in SAH of unknown origin. Long-term neurological outcomes are generally good. A thorough evaluation to rule out an etiology of hemorrhage is necessary; however, imaging beyond 6 weeks from ictus has little utility, and rebleeding is unexpected.

Description of the vasospasm phenomena following perimesencephalic nonaneurysmal subarachnoid hemorrhage

Background. Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PM-NASAH) is characterized by a benign course compared with aneurysmal SAH. While vasospasm (VS) after aneurysmal SAH is considered responsible for serious complications, VS post-PM-NASAH is not well documented. Our purpose was to characterize the incidence and course of VS among 63 patients—one of the largest databases of PM-NASAH patients with documented blood flow velocities in the literature. Methods. Data from 63 patients that were admitted with PM-NASAH from 2000 to 2012 and underwent transcranial Doppler tests to assess cranial vessel flow velocity was analyzed. Results. On average, the maximal flow velocity was measured on the 7th day after hemorrhage. Higher risk for VS was associated with younger age, female sex, and higher Hunt and Hess scores, a lower risk for patients treated with statins (P < 0.05). Using velocity thresholds for diagnosis of VS, 49.2% showed evidence of VS. This is the first description of blood flow velocities in PM-NASAH. VS average onset was on the 4th day, average cessation on day 15 after hemorrhage. No patients showed clinical manifestation of VS. Conclusions. VS post-PM-NASAH is not as rare as previously believed. However, its lack of clinical significance raises questions regarding the need for diagnosis and may suggest a less intensive treatment protocol.

Subarachnoid hemorrhage with negative initial catheter angiography: a review of 254 cases evaluating patient clinical outcome and efficacy of short- and long-term repeat angiography

BACKGROUND

Subarachnoid hemorrhage (SAH) is found to have no vascular origin by initial catheter angiography in approximately 15% of cases. The most appropriate course for the type and frequency of additional diagnostic workup remains controversial.

OBJECTIVE

To retrospectively assess the diagnostic yield of short-term and long-term repeat catheter angiography in the era of advanced imaging.

METHODS

Between 2003 and 2011, 254 consecutive patients diagnosed with SAH had negative initial angiography. SAH was perimesencephalic (PM) in 46.5% and nonperimesencephalic (NPM) in 53.5%. Angiography was repeated at 1-week (short-term) and 6-week (long-term) intervals from the initial negative angiogram.

RESULTS

Ten of 254 patients had a vascular source of hemorrhage on short-term follow-up angiography with a diagnostic yield of 3.9%. One hundred seventy-four patients with negative findings on the first 2 angiograms received a third angiogram, and 7 of these patients were found to have a vascular abnormality. The estimated yield of this third angiogram was 4.0%. The overall diagnostic yield of repeat angiography was 0% in the PM group and 12.5% in the NPM group. The diagnostic yield of short-term and long-term follow-up angiography in patients with NPM SAH was 7.3% and 7.8%, respectively. NPM patients were more likely to experience vasospasm and hydrocephalus requiring external ventricular drainage or cerebrospinal fluid diversion than PM patients.

CONCLUSION

Our results support a protocol of short-term and long-term angiographic follow-up in patients with NPM SAH and negative initial angiography. Aggressive protocols of follow-up angiography may not be necessary in patients with PM SAH.

Repeated neurovascular imaging in subarachnoid hemorrhage when initial studies are negative

Approximately 15% of patients with non-traumatic subarachnoid hemorrhage have no causative lesion identified on their initial angiogram. We present two patients with non-traumatic subarachnoid hemorrhage with negative initial angiograms who were subsequently found to have small basilar perforator aneurysms on delayed neurovascular imaging. We discuss the possible mechanisms for false negative diagnostic cerebral angiograms. These patients support the current standard of care with repeat angiography in cases of subarachnoid hemorrhage when no causative lesion can be identified on initial neurovascular imaging.

Repeat digital subtraction angiography after a negative baseline assessment in nonperimesencephalic subarachnoid hemorrhage: a pooled data meta-analysis

OBJECT

A repeat digital subtraction angiography (DSA) study of the cranial vasculature is routinely performed in patients with diffuse nonperimesencephalic subarachnoid hemorrhage (SAH) after negative baseline CT angiography (CTA) and DSA studies. However, DSA carries a low but substantial risk of neurological complications. Therefore, the authors evaluated the added value of repeat DSA in patients with initial angiographically negative diffuse nonperimesencephalic SAH.

METHODS

A systematic review of the contemporary literature was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Studies from January 2000 onward were reviewed since imaging modalities have much improved over the last decade. A pooled analysis was conducted to identify the detection rate of repeat DSA. In addition, the diagnostic yield of repeat DSAs in a prospectively maintained single-center series of 1051 consecutive patients with SAH was added to the analysis.

RESULTS

An initial search of the literature yielded 179 studies, 8 of which met the selection criteria. Another 45 patients from the authors' institution were included in the study, providing 368 patients eligible for the pooled analysis. In 37 patients (10.0%, 95% CI 7.4%-13.6%) an aneurysm was detected on repeat DSA. The timing of the repeat DSA varied from 1 to 6 weeks after the initial DSA. The use of 3D techniques was poorly described among these studies, and no direct comparisons between CTA and DSA were made.

CONCLUSIONS

Repeat DSA is still warranted in patients with a diffuse nonperimesencephalic SAH and negative initial assessment. However, the exact timing of the repeat DSA is subject to debate.

Fusiform aneurysms of the lenticulostriate artery

Lenticulostriate artery aneurysms are rare, can be difficult to diagnoze, and when they rupture they are often associated with deep intraparenchymal hemorrhages. In particular, fusiform, dissecting aneurysms of a distal lenticulostriate artery are extremely rare. Typically, they are usually associated with underlying systemic conditions such as systemic lupus erythematosus, moyamoya disease, and substance abuse. Given their usual small size and location, these aneurysms may be difficult to detect with angiography and can be challenging to treat with either endovascular or microsurgical techniques. We provide background information, review the existing treatment experiences reported in the literature, and present a discussion regarding the optimal management using an illustrative clinical vignette. Parent artery obliteration can be a safe and effective treatment in these rare aneurysms.

Subarachnoid hemorrhage with negative baseline digital subtraction angiography: is repeat digital subtraction angiography necessary?

INTRODUCTION

Patients with negative initial digital subtraction angiography (DSA) are at significant risk for re-bleeding, which can lead to severe disability and death. The purpose of this study was to evaluate the necessity of repeat DSA in subgroups of patients with subarachnoid hemorrhage (SAH) with negative initial DSA.

METHODS

A total of 904 spontaneous SAH patients were admitted to our department between May 2005 and May 2012. Twenty eight patients were selected for inclusion in this study because repeated DSA performed due to the etiology of the SAH could not be demonstrated on the initial DSA. According to the SAH pattern on initial computed tomography scans, patients were divided into perimesencephalic nonaneurysmal SAH (PN-SAH) and non PN-SAH (NPN-SAH) groups. Repeat DSA was performed in all patients, and two of these patients underwent a third DSA.

RESULTS

Of the 904 patients, 28 patients (3.1%) had no vascular abnormality on initial DSA. Sixteen PN-SAH patients underwent a repeat DSA; however, no aneurysms were found. In contrast, 12 patients with NPN-SAH underwent repeat DSA, with detection of two cerebral aneurysms. Overall, the false-negative rate of the initial DSA was 7.1% (2/28 patients). No significant differences in false-negative results on initial DSA were observed between the PN-SAH and NPN-SAH groups.

CONCLUSION

In the line with the results of the current study, we should be highly suspicious of patients with a nonaneurysmal SAH, especially those with a NPN-SAH pattern. In order to reduce the morbidity and mortality resulting from a misdiagnosis, repeat DSA is necessary, and exclusion of an aneurysm is important.

Diagnostic yield of catheter angiography in patients with subarachnoid hemorrhage and negative initial noninvasive neurovascular examinations

BACKGROUND AND PURPOSE

The yield of DSA in patients with SAH and negative initial noninvasive neurovascular examinations (CTA or MRA) is not well-understood. This study aimed to determine the yield of DSA for the detection of causative vascular lesions in this clinical scenario.

MATERIALS AND METHODS

We examined the yield of DSA for the detection of causative vascular lesions in a cohort of patients presenting to our institution with SAH and negative initial noninvasive neurovascular examinations during a 5-year period. Two experienced neuroradiologists independently evaluated the NCCT to determine the SAH pattern (diffuse, perimesencephalic, or peripheral sulcal) and the catheter angiograms to assess the presence of a causative vascular lesion.

RESULTS

Fifty-five patients were included in the study, with a mean age of 58.2 years (median, 58 years; range, 25-88 years). Twenty-eight patients were men (50.9%), and 27 were women (49.1%). The initial noninvasive examination was a CTA in 47 patients (85.5%) and an MRA in 8 patients (14.5%). Thirty-three patients had diffuse SAH (60%); 11, perimesencephalic SAH (20%); and 11, peripheral sulcal SAH (20%). DSA demonstrated a causative vascular lesion in 6 patients (10.9%), 5 of whom had diffuse SAH (yield of 15.2%) and 1 of whom had peripheral sulcal SAH (yield of 9.1%). No causative vascular lesions were found in patients with perimesencephalic SAH.

CONCLUSIONS

DSA is a valuable tool in the evaluation of patients with diffuse and peripheral sulcal SAH who have negative initial noninvasive neurovascular examinations, demonstrating a causative vascular lesion in 15.2% and 9.1% of patients, respectively.

Angiogram-negative subarachnoid hemorrhage: relationship between bleeding pattern and clinical outcome

BACKGROUND

Angiogram-negative subarachnoid hemorrhage (anSAH) accounts for 15% of spontaneous SAH. Recent studies suggest the outcome and diagnostic yield in anSAH differ based on initial bleeding pattern. We present a single-center experience in managing patients with SAH and negative initial digital-subtracted angiogram (DSA).

METHODS

Records of all patients with anSAH were reviewed. Bleeding pattern was determined from computed tomography (CT) and was categorized as perimesencephalic (PMN), diffuse, cortical, or xanthochromia (blood not detectable by CT). Diagnostic yield, in-hospital complications, and outcome parameters were analyzed.

RESULTS

Of 352 patients admitted with spontaneous SAH from 2003 to 2008, 68 (19.3%) had negative initial DSA. Mean age was 59.5 ± 14, and 33 were female. By CT, 27 (39.7%) patients exhibited PMN SAH, 33 (48.5%) diffuse SAH, 6 (8.8%) cortical SAH, and 2 (2.9%) xanthochromia only. Sixty-one patients had good Hunt and Hess (H/H) grades (I-III) and seven had poor grades (IV-V). Additional diagnostic studies included repeat angiogram (54), brain and C-spine magnetic resonance imaging (20), and repeat CTA (15). A structural bleeding cause was determined in six (8.8%) patients, 4 of which had diffuse SAH and 2 cortical SAH. Among these, two aneurysms (2.9%) were detected and surgically clipped, and both had diffuse SAH. Twenty-nine patients (42.6%) experienced medical complications, with infection (18), cardiovascular problems (12), and vasospasm (10) being the most frequent events. Additional surgeries included 13 ventriculoperitoneal shunts, 4 tracheostomies, and 9 gastric tube placements. Favorable outcome (mRS = 0-2) was recorded in 49 (72.1%) patients and unfavorable (3-6) in 19 (17.49%), with 1 (1.2%) in-hospital death. Multivariable logistic regression revealed older age and diffuse bleeding pattern were significant predictors of unfavorable outcome.

CONCLUSIONS

The overall incidence of true aneurysms in patients with angiogram-negative SAH is low (2.9%). Initial bleeding pattern strongly correlates with diagnostic yield and clinical outcome. Diffuse bleeding pattern is associated with significantly higher diagnostic yield, more in-hospital complications, and worse clinical outcome. Patients with initial imaging characteristics other than diffuse pattern SAH developed few disease related complications, with the majority of in-hospital adverse events treatment related.

Diagnostic yield of computed tomography angiography and magnetic resonance angiography in patients with catheter angiography-negative subarachnoid hemorrhage

OBJECT

The yield of CT angiography (CTA) and MR angiography (MRA) in patients with subarachnoid hemorrhage (SAH) who have a negative initial catheter angiogram is currently not well understood. This study aims to determine the yield of CTA and MRA in a prospective cohort of patients with SAH and a negative initial catheter angiogram.

METHODS

From January 1, 2005, until September 1, 2010, the authors instituted a prospective protocol in which patients with SAH-as documented by noncontrast CT or CSF xanthochromia and a negative initial catheter angiogram- were evaluated using CTA and MRA to assess for causative cerebral aneurysms. Two neuroradiologists independently evaluated the noncontrast CT scans to determine the SAH pattern (perimesencephalic or not) and the CT and MR angiograms to assess for causative cerebral aneurysms.

RESULTS

Seventy-seven patients were included, with a mean age of 52.8 years (median 54 years, range 19-88 years). Fifty patients were female (64.9%) and 27 male (35.1%). Forty-three patients had nonperimesencephalic SAH (55.8%), 29 patients had perimesencephalic SAH (37.7%), and 5 patients had CSF xanthochromia (6.5%). Computed tomography angiography demonstrated a causative cerebral aneurysm in 4 patients (5.2% yield), all of whom had nonperimesencephalic SAH (9.3% yield). Mean aneurysm size was 2.6 mm (range 2.1-3.3 mm). Magnetic resonance angiography demonstrated only 1 of these aneurysms. No causative cerebral aneurysms were found in patients with perimesencephalic SAH or CSF xanthochromia.

CONCLUSIONS

Computed tomography angiography is a valuable adjunct in the evaluation of patients with nonperimesencephalic SAH who have a negative initial catheter angiogram, demonstrating a causative cerebral aneurysm in 9.3% of patients.

Vasospasm after spontaneous angiographically negative subarachnoid hemorrhage

BACKGROUND

Vasospasm, delayed infarcts and clinical deterioration due to delayed cerebral ischemia (CD-DCI) following digital subtraction angiography (DSA)-negative, spontaneous subarachnoid hemorrhage (SAH) are infrequently and inconsistently described in the literature.

METHODS

To quantify and characterize rates of each, we reviewed our own series of 77 patients with DSA-negative, spontaneous SAH. Employing a PubMed search, we reviewed the literature and calculated directly adjusted overall rates of vasospasm, delayed infarcts and CD-DCI.

RESULTS

In our own patient cohort, 26 % of patients suffered vasospasm, 4 % delayed infarcts and 4 % CD-DCI. Higher Hunt-Hess grade and diffuse SAH pattern were associated with higher rates of each. Incorporating results from 18 studies in the literature, the directly adjusted overall rate of vasospasm following DSA-negative SAH was 16.3 % (95 % CI 12.3-21.1). Adjusted overall rates of delayed infarcts and CD-DCI were 3.4 % (95 % CI 1.9-5.5) and 6.8 % (95 % CI 5.0-9.1), respectively. For the subgroup of patients with diffuse SAH, the rates of vasospasm and CD-DCI were 31.3 % (95 % CI 21.6-43.9) and 9.7 % (95 % CI 7.0-13.0), respectively, while in patients with perimesencephalic SAH, respective rates were 13.1 % (95 % CI 7.7-20.7) and 2.4 % (95 % CI 1.0-4.8). A mixed-effects meta-analysis revealed an odds ratio for CD-DCI in diffuse SAH compared to perimesencephalic SAH of 3.79 (p = 0.009).

CONCLUSION

Although they are seen less frequently in patients with DSA-negative spontaneous SAH, vasospasm, delayed infarcts and CD-DCI do occur and may require endovascular therapy. Risk factors include a diffuse hemorrhage pattern and higher Hunt-Hess grade.

Diagnostic yield of repeat catheter angiography in patients with catheter and computed tomography angiography negative subarachnoid hemorrhage

BACKGROUND

The yield of repeat catheter angiography in patients with subarachnoid hemorrhage (SAH) who have negative initial catheter and computed tomography (CT) angiograms is not well understood.

OBJECTIVE

To determine the yield of repeat catheter angiography in a prospective cohort of patients with SAH and negative initial catheter and CT angiograms.

METHODS

From January 1, 2005, until September 1, 2010, we instituted a prospective protocol in which patients with SAH documented by noncontrast CT (NCCT) or cerebrospinal fluid (CSF) xanthochromia and negative initial catheter and CT angiograms were evaluated with repeat catheter angiography 7 days and 3 months after presentation to assess for causative vascular abnormalities.

RESULTS

Seventy-two patients were included, with a mean age of 53.1 years (median, 53.5 years; range, 19-88 years). Forty-six patients were female (63.9%) and 26 male (36.1%). Thirty-nine patients had nonperimesencephalic SAH (54.2%), 29 patients had perimesencephalic SAH (40.3%), and 4 patients had CSF xanthochromia (5.5%). The first repeat catheter angiogram performed 7 days after presentation demonstrated a causative vascular abnormality in 3 patients (yield of 4.2%), 2 of which had nonperimesencephalic SAH (yield of 5.1%), and 1 had perimesencephalic SAH (yield of 3.4%). The second repeat catheter angiogram performed in 43 patients (59.7%) did not demonstrate any causative vascular abnormalities. No causative abnormalities were found in patients with CSF xanthochromia.

CONCLUSION

Repeat catheter angiography performed 7 days after presentation is valuable in the evaluation of patients with SAH who have negative initial catheter and CT angiograms, demonstrating a causative vascular abnormality in 4.2% of patients.

Type 1 perimedullary arteriovenous fistula with subarachnoid hemorrhage: utility of contrast-enhanced 3D gradient-echo technique

PURPOSE

In patients with perimedullary arteriovenous fistula (AVF) with subarachnoid hemorrhage (SAH), knowledge of lesion location is necessary to select the appropriate approach for catheter spinal angiography. We evaluated the utility of 3-dimensional (3D) fast imaging with steady-state precession (FISP) sequence for detecting type 1 perimedullary AVF with SAH.

MATERIALS AND METHODS

We evaluated 4 patients (2 men, 2 women, aged 53 to 68 years, mean age, 59.25 years) with type 1 perimedullary AVF who presented with SAH and underwent conventional spin-echo MR and contrast-enhanced 3D FISP imaging. Two neuroradiologists assessed detection of vascular lesions and delineation of their relationships to the adjacent vessels. Catheter angiography was used as the reference standard and compared with the MR findings.

RESULTS

Perimedullary AVF was located at the medullocervical junction in 2 patients, cervical spine in one, and thoracic spine in one. For all patients, use of contrast-enhanced 3D FISP in addition to conventional MR imaging improved lesion detection and delineation of the relationship between the lesion and surrounding vessels.

CONCLUSION

Contrast-enhanced 3D FISP imaging was useful for detecting and delineating type 1 perimedullary AVF with SAH.

Perimesencephalic subarachnoid hemorrhage: risk factors, clinical presentations, and outcome

BACKGROUND

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) appears to have an origin and natural history distinct from aneurysm rupture. However, the risk factors and complications of this pattern are still in debate. We performed a study with goals of comparing PNSH risk factors and clinical presentations with other sorts of spontaneous subarachnoid hemorrhages (SAH) and exhibit the PNSH outcome and prognosis.

METHODS

Retrospective review of patients who experienced SAH between May 2006 and July 2008 in the First Affiliated Hospital of Chongqing Medical University was undertaken. Patients were categorized as perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH), nonperimesencephalic nonaneurysmal subarachnoid hemorrhage (NPNSH), aneurismal subarachnoid hemorrhage (ASH), and uncertain SAH of which the patterns were not clear. The possible risk factors and clinical presentations within the three groups were used to proceed for statistical analysis.

RESULTS

A total of 159 residents were identified. Among of them, 12 patients had the perimesencephalic pattern. Patients with PNSH showed less likelihood with the female (P=0.029), alcohol consumption (P=0.033), hypertensive (P=0.005), diabetes (P=0.013) or hyperlipidemia (P=0.034) when compared with aneurismal SAH. The clinical presentations of this pattern showed less conscious disturbance (P=0.004), vomiting (P=0.005), or poor Hunt & Hess Grade (P=0.003). There was one death among PNSH patients during 12 months mean follow-up.

CONCLUSIONS

Patients with PNSH present better clinical course than other forms of SAH, which could assist the diagnosis of this pattern. The moderate clinical course may suggest clinician apt to exclude aneurysm rupture. However, similar presents in remaining nonaneurysmal subarachnoid hemorrhage might suggest benign entities in other forms of nonaneurysmal subarachnoid hemorrhage.

Thrombosis and subsequent recanalization of a ruptured intracranial aneurysm in 2 children, demonstrating the value of repeating catheter angiography after an initial negative study

The cases of 2 children with true aneurysmal subarachnoid hemorrhages (SAHs) and initial false-negative angiograms are reported. In both cases, the initial angiogram was of adequate technical quality and included the projections on which aneurysms were later documented. There was no significant vasospasm at the time of initial angiography; therefore, transient aneurysm sac thrombosis was the most likely explanation for the initial false-negative studies. It is particularly interesting to note that 1 of the 2 patients had a pattern of hemorrhage compatible with the most limited definition of a perimesencephalic SAH, that is, a small prepontine cistern hemorrhage. If a second angiogram had been deemed unnecessary based on that criterion alone, a ruptured basilar tip aneurysm would have escaped detection and treatment.