The negative angiogram in subarachnoid haemorrhage

The diagnostic yield of repeat computed tomography angiography in cases of spontaneous subarachnoid haemorrhage after negative initial digital subtraction angiography

Purpose

It is currently unclear how useful repeat computed tomography angiography (CTA) is in spontaneous subarachnoid haemorrhage (SAH) patients after negative initial digital subtraction angiography (DSA). The purpose of this study is to assess the yield of repeat CTA for the detection of causative vascular lesions in patients with SAH in whom there has been a negative initial DSA.

Material and methods

This observational retrospective study was carried out from January 2013 to July 2022 at a single institution. Analysis of the SAH pattern on unenhanced CT showed that patients were divided into perimesencephalic SAH and diffuse SAH groups. A repeat CTA was performed on all spontaneous SAH patients who had a nega-tive initial CTA and DSA within a 2-week period. An interventional neuroradiologist and a diagnostic radiologist examined all images to search for causative vascular abnormalities.

Results

Forty-seven patients were included in our study, with a median age of 55 years and a range of 28-81 years. Thirty-seven had diffuse SAH (66%), and 16 had perimesencephalic SAH (34%). The repeat CTA revealed 2 causa-tive vascular lesions (a right PICA aneurysm and a mycotic aneurysm) in 2 separate patients (yield of 4.3%), both of whom had diffuse SAH (yield of 6.5%). In retrospect, none of these vascular lesions were evident in the initial CTA and DSA. No evidence of re-bleeding was observed in the follow-up period.

Conclusions

It is beneficial to repeat CTA when evaluating patients with diffuse SAH who initially present with nega-tive initial DSA. For occult aneurysms, the diagnostic yield of the follow-up CTA is 6.5%.

Radiological investigations in non-aneurysmal subarachnoid haemorrhage: A 5-year review

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All patients with a Fisher grade 2 bleed and a negative CT angiogram had catheter angiography negative for any abnormality.

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Neuroradiologists identified vascular abnormalities not reported by district general hospitals.

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Follow-up MRI may be a useful adjunct in subarachnoid haemorrhage.

Current Clinical Applications of Intracranial Vessel Wall MR Imaging

Intracranial vessel wall MR imaging (VWI) is increasingly being used as a valuable adjunct to conventional angiographic imaging techniques. This article will provide an updated review on intracranial VWI protocols and image interpretation. We review VWI technical considerations, describe common VWI imaging features of different intracranial vasculopathies and show illustrative cases. We review the role of VWI for differentiating among steno-occlusive vasculopathies, such as intracranial atherosclerotic plaque, dissections and Moyamoya disease. We also highlight how VWI may be used for the diagnostic work-up and surveillance of patients with vasculitis of the central nervous system and cerebral aneurysms.

Usefulness of 3D High-resolution Vessel Wall MRI in Diffuse Nonaneurysmal SAH Patients

PURPOSE

In 15-20% of patients with nontraumatic diffuse subarachnoid hemorrhage (SAH), the initial conventional angiography does not reveal a causative vascular abnormality, such as intracranial aneurysm. In this study, we evaluated clinical utility of 3D high-resolution vessel wall magnetic resonance imaging (HR-VWI) in patients with diffuse nonaneurysmal SAH.

METHODS

A total of 17 patients with diffuse nonaneurysmal SAH were included in this retrospective study. We characterized demographics and HR-VWI findings and reviewed the clinical management and outcomes.

RESULTS

Of the patients 14 (14/17; 82.4%,) showed abnormal findings on HR-VWI, including 5 with intracranial dissections (29.4%), 3 with blood blister-like aneurysm (17.6%), 1 with ruptured fusiform aneurysm (5.9%), and 5 with focal nodular wall enhancement without unclassified pathology (29.4%). Of these patients were treated with endovascular management. Most patients (16/17) had a favorable modified Rankin scale scores of 0-2 on discharge.

CONCLUSION

The 3D HR-VWI revealed various hidden pathologies, such as intracranial arterial dissection, blood blister-like aneurysm, and fusiform aneurysm in patients with diffuse nonaneurysmal SAH. In addition, 3D HR-VWI had an impact on the management of SAH. The 3D HR-VWI can be a complementary diagnostic method for patients with diffuse nonaneurysmal SAH in a research or clinical setting.

Subarachnoid hemorrhage and COVID-19: Association or coincidence?

ABSTRACT

Some evidences suggest the involvement of the central nervous system in patients infected with SARS-CoV-2. We aim to analyze possible associations between coronavirus disease 2019 (COVID-19) pandemic and spontaneous subarachnoid hemorrhage (SAH), in a comprehensive neurological center.We conducted a retrospective case series of 4 patients infected by COVID-19, who developed spontaneous SAH. Clinical data were extracted from electronic medical records.Between March 24, 2020, and May 22, 2020, 4 cases (3 females; 1 male) of SAH were identified in patients infected with SARS-CoV-2, in a comprehensive neurological center in Brazil. The median age was 55.25 years (range 36 -71). COVID-19-related pneumonia was severe in 3 out of 4 cases, and all patients required critical care support during hospitalization. The patients developed Fisher grade III and IV SAH. Digital subtraction angiography (DSA) was performed in 3 of the 4 patients. However, in only 1 case, an aneurysm was identified. Inflammatory blood tests were elevated in all cases, with an average D-dimer of 2336 μg/L and mean C-reactive protein (CRP) of 3835 mg/dl The outcome was poor in the majority of the patients, with 1 death (25%); 2 (50%) remained severely neurologically affected (mRS:4); and 1 (25%) had slight disability (mRS:2).This study shows a series of 4 rare cases of SHA associated with COVID-19. The possible mechanisms underlying the involvement of SARSCoV-2 and SHA is yet to be fully understood. Therefore, SHA should be included in severe neurological manifestations in patients infected by this virus.

Digital subtraction cerebral angiography after negative computed tomography angiography findings in non-traumatic subarachnoid hemorrhage

Background

CT angiography (CTA) is widely used for the detection of vascular lesions in patients with non-traumatic subarachnoid hemorrhage (ntSAH); however, digital subtraction angiography (DSA) remains the gold standard for diagnosis. Our aim was to analyze the diagnostic yield of DSA after negative high-resolution CTA findings.

Methods

Records of patients with a CTA-negative ntSAH at a single institution from 2014 to 2018 were retrospectively analyzed. ntSAH patterns were categorized as cortical, perimesencephalic, or diffuse. Subsequent DSA findings were compared across the three cohorts.

Results

A total of 186 patients had CTA-negative ntSAH. The ntSAH pattern was identified as cortical (n=77, 41.4%), diffuse (n=60, 32.3%), or perimesencephalic (n=49, 26.3%). In eight patients (4%), DSA revealed a vascular lesion (one cervical arteriovenous fistula and seven atypical aneurysms) after negative CTA findings. All eight patients with positive DSA findings had diffuse SAH (13% of patients with a diffuse pattern). The seven aneurysms included four blister or dissecting (two basilar artery, one superior cerebellar artery, and one dorsal wall internal carotid artery), two fusiform (one posterior communicating artery and one anterior spinal artery), and one saccular aneurysm (middle cerebral artery).

Conclusion

DSA identified a causative lesion in 4% of patients with CTA-negative ntSAH, but only in patients with diffuse ntSAH. Most of the lesions detected were atypical aneurysms and were found on delayed angiograms. These results suggest that DSA can help to diagnose CTA-negative ntSAH caused by unusual aneurysms, and repeat DSA may be needed only for patients with diffuse ntSAH.

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.

Risk factors for shunt dependency in patients suffering from spontaneous, non-aneurysmal subarachnoid hemorrhage

Patients presenting with spontaneous, non-aneurysmal subarachnoid hemorrhage (SAH) achieve better outcomes compared to patients with aneurysmal SAH. Nevertheless, some patients develop shunt-dependent hydrocephalus during treatment course. We therefore analyzed our neurovascular database to identify factors determining shunt dependency after non-aneurysmal SAH. From 2006 to 2016, 131 patients suffering from spontaneous, non-aneurysmal SAH were admitted to our department. Patients were stratified according to the distribution of cisternal blood into patients with perimesencephalic SAH (pSAH) versus non-perimesencephalic SAH (npSAH). Outcome was assessed according to the modified Rankin Scale (mRS) at 6 months and stratified into favorable (mRS 0-2) versus unfavorable (mRS 3-6). A multivariate analysis was performed to identify predictors of shunt dependency in patients suffering from non-aneurysmal SAH. Overall, 18 of 131 patients suffering from non-aneurysmal SAH developed shunt dependency (14%). In detail, patients with npSAH developed significantly more often shunt dependency during treatment course, when compared to patients with pSAH (p = 0.02). Furthermore, patients with acute hydrocephalus, presence of intraventricular hemorrhage, presence of clinical vasospasm, and anticoagulation medication prior SAH developed significantly more often shunt dependency, when compared to patients without (p < 0.0001). However, "acute hydrocephalus" was the only significant and independent predictor for shunt dependency in all patients with non-aneurysmal SAH in the multivariate analysis (p < 0.0001). The present study identified acute hydrocephalus with the necessity of CSF diversion as significant and independent risk factor for the development of shunt dependency during treatment course in patients suffering from non-aneurysmal SAH.

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.

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.

Clinical management guidelines for subarachnoid haemorrhage. Diagnosis and treatment

OBJECTIVE

To update the Spanish Society of Neurology's guidelines for subarachnoid haemorrhage diagnosis and treatment.

MATERIAL AND METHODS

A review and analysis of the existing literature. Recommendations are given based on the level of evidence for each study reviewed.

RESULTS

The most common cause of spontaneous subarachnoid haemorrhage (SAH) is cerebral aneurysm rupture. Its estimated incidence in Spain is 9/100 000 inhabitants/year with a relative frequency of approximately 5% of all strokes. Hypertension and smoking are the main risk factors. Stroke patients require treatment in a specialised centre. Admission to a stroke unit should be considered for SAH patients whose initial clinical condition is good (Grades I or II on the Hunt and Hess scale). We recommend early exclusion of aneurysms from the circulation. The diagnostic study of choice for SAH is brain CT (computed tomography) without contrast. If the test is negative and SAH is still suspected, a lumbar puncture should then be performed. The diagnostic tests recommended in order to determine the source of the haemorrhage are MRI (magnetic resonance imaging) and angiography. Doppler ultrasonography studies are very useful for diagnosing and monitoring vasospasm. Nimodipine is recommended for preventing delayed cerebral ischaemia. Blood pressure treatment and neurovascular intervention may be considered in treating refractory vasospasm.

CONCLUSIONS

SAH is a severe and complex disease which must be managed in specialised centres by professionals with ample experience in relevant diagnostic and therapeutic processes.

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.

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.

Endoscopic third ventriculostomy for hydrocephalus after perimesencephalic subarachnoid hemorrhage: initial experience in three patients

BACKGROUND

To review the outcome after endoscopic third ventriculostomy (ETV) for symptomatic, persistent hydrocephalus in three patients with perimesencephalic angiographically negative subarachnoid hemorrhage (PNH) who were dependent on an external ventricular drain (EVD).

METHODS

All patients initially presented with severe headache, nuchal rigidity, confusion and lethargy (Hunt-Hess Grade II or III), and persistent, EVD-dependent hydrocephalus. Cranial CT images in each revealed acute hydrocephalus and perimesencephalic hemorrhage pattern with a heavy clot burden (Fisher grade 3). A 3D-CT angiogram on admission and two four-vessel cerebral angiograms failed to demonstrate a bleeding source. All three patients failed trial EVD clamping, with clinical deterioration and elevated intracranial pressure (ICP). ETV was performed with a 0-degree endoscope in a 4.6-mm irrigating sheath using an endoscopic-coring/"cookie-cut" technique. An EVD was left in place for postoperative ICP monitoring but was clamped.

RESULTS

ETV was accomplished in all patients. In one case, a tiny basilar tip aneurysm was seen during the endoscopic procedure. Intraoperatively, the prepontine cistern revealed dense, degraded blood products. Postprocedure ICP measurements were reduced to normal range. Clinical improvement, normal ICP readings, and/or radiographic evidence of resolution of hydrocephalus allowed uneventful removal of the EVD within 36-48 h post-ETV in all patients. All remained headache-free, with a normal neurological examination, during a follow-up period of 10, 11, and 12 months, respectively.

CONCLUSION

To our knowledge, this is the first report of ETV for PNH with hydrocephalus and the first report of a basilar tip microaneurysm seen intraoperatively during ETV. ETV is a viable treatment option for refractory hydrocephalus secondary to a perimesencephalic pattern of subarachnoid hemorrhage (SAH). Its early application can avoid placement of a ventriculoperitoneal shunt, curtail the extended use of an EVD, and reduce the associated infection risks. Despite thorough angiographic investigation for an aneurysmal cause of SAH, a "microaneurysm" of the basilar artery was found at ETV. No complication or rebleeding was encountered.

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.

Outcome correlates with blood distribution in subarachnoid hemorrhage of unknown origin

PURPOSE

Between 15 and 30 % of patients with subarachnoid hemorrhage (SAH) have no bleeding source and usually have a benign clinical course and outcome. The objectives of this study were to classify the pattern of blood distribution on initial computed tomography (CT) and to correlate it with clinical outcome in aneurysmal (ASAH) and SAH of unknown origin (SAHuO).

METHODS

We reviewed 112 CTs of SAHuO and 104 CTs of ASAH patients. Blood distribution was classified according to a new grading system (type 0-4) and correlated to Hunt and Hess (H&H) grade and modified Rankin scores (MRS) at short- and long-term follow-up.

RESULTS

Fifty percent of 112 SAHuO patients were classified as type 0 (no visible blood on CT) or 1 (blood restricted to prepontine cisterns). Most ASAH patients presented with bleeding into the lateral Sylvian fissure (66%; type 3) or with intracerebral hemorrhage (27%; type 4) whereas types 0 and 1 were not observed. SAHuO patients were in better clinical condition on admission than ASAH patients (p < 0.0001). H&H grades of SAHuO patients correlated with the amount of subarachnoid blood according to the new classification (p = 0.004). Short-term outcome was obtained from 100% and long-term outcome from 95% patients (follow-up 29 +/- 31 months). Short- and long-term MRS correlated with blood distribution in SAHuO patients (p = 0.012) and was significantly better than in ASAH patients (p < 0.0001). No correlation was observed between blood distribution, H&H grade, and short- and long-term outcome in aneurysmal patients.

CONCLUSIONS

In SAH of unknown origin, a new classification allows to predict outcome based on the extent of blood on CT.

Clinical course of nontraumatic, nonaneurysmal subarachnoid hemorrhage: a single-institution experience

Object

Angiogram-negative subarachnoid hemorrhage (SAH) accounts for 15% of nontraumatic SAH and has been reported with low morbidity and mortality rates. We report on a large series of patients with angiogram-negative SAH who experienced an atypical nonbenign clinical course.

Methods

Between December 2001 and November 2006, 95 patients with spontaneous nonaneurysmal SAH and negative initial angiographic evaluation were treated at the University of Florida. The authors retrospectively reviewed the patients' medical records and radiological images to determine associated morbidity and mortality.

Results

Aneurysms were found in 6 of the 95 patients on follow-up imaging after an initial negative angiogram (6.3% false negative rate); these patients were excluded leaving 89 patients as the study group. Hydrocephalus necessitating temporary CSF diversion developed in 22 of these patients (25%); 12 (13%) ultimately required permanent CSF diversion. Clinically significant vasospasm developed in 4 patients (4%), and 2 (2%) had cerebral infarctions. Three patients (3%) died.

Conclusions

The authors' experience with a large series of angiogram-negative SAH patients who had an atypical nonbenign clinical course associated with hydrocephalus, vasospasm, stroke, and mortality differs significantly from previously published case series of angiogram-negative SAH.

Spinal vascular malformations in non-perimesencephalic subarachnoid hemorrhage

OBJECTIVE

In patients with non-traumatic subarachnoid hemorrhage (SAH) and no evidence for a cerebral aneurysm on angiography, a frequent cause of the hemorrhage is perimesencephalic hemorrhage or other cerebral vascular pathology. In some patients no cause is found. The exact incidence of a spinal vascular malformation (SVM) as the origin for the SAH is not known. We assessed the occurrence of SVM in angiogram-negative, non-perimesencephalic subarachnoid hemorrhage (NPSAH).

METHODS

47 patients (from a consecutive cohort of 632) were identified with an angiogramnegative, non-perimesencephalic subarachnoid hemorrhage and 42 of these were analyzed by performing MR-imaging of the complete spinal neuraxis with additional spinal angiography on indication.

RESULTS

In four patients a spinal vascular malformation was identified as the cause of the SAH, indicating an incidence of 9 % of SVM in NPSAH, and an incidence of 1 % of SVM in all patients with SAH.

INTERPRETATION

Systematic analysis of angiogram-negative, non-perimesencephalic subarachnoid hemorrhage by MR imaging of the complete spinal neuraxis yields a higher incidence of SVM than previously documented. We recommend MR imaging of the complete spinal neuraxis in patients with a non-perimesencephalic subarachnoid hemorrhage in whom no cause for the hemorrhage has been found.

Straight sinus stenosis as a proposed cause of perimesencephalic non-aneurysmal haemorrhage

Perimesencephalic nonaneurysmal haemorrhage (PMNH), a term first coined in 1985, is a diagnosis of exclusion. It is considered a benign form of subarachnoid haemorrhage with a good prognosis and a low risk of rebleeding. Its precise aetiology has not yet been determined. Haemorrhage of venous origin has been proposed as a cause, and has been demonstrated to be associated with venous abnormalities of the basal vein of Rosenthal. We present a patient with PMNH in whom an 80% stenosis at the union of the vein of Galen with the straight sinus is demonstrated. We thus propose hypertensive venous rupture secondary to venous sinus stenosis as an alternative cause for PMNH.

Detection of intracranial aneurysms with 64 channel multidetector row computed tomography: Comparison with digital subtraction angiography

PURPOSE

To compare the contribution of 64 channel multidetector row computed tomography angiography (64MDCT-angiography) with digital subtraction angiography (DSA) in the detection of intracranial aneurysms.

METHODS AND MATERIALS

Twenty-nine patients (10 males and 19 females, age: 40-84 years; average: 61.9 years) with clinical and imaging findings strongly suggesting the presence of subaracnoid hemorrhage underwent 64MDCT-angiography and DSA with a short interval between the two examinations (less than 12 h-5 days). CT parameters were: 64 mm x 0.5 mm collimation, pitch-0.828 and helical pitch-53. DSA were performed with standard technique (four vessel catheterization) and multiple projections. Axial CT scans as well as maximum intensity projection, volume rendering and multiplanar reformations and angiographic views were independently reviewed by four readers (two for 64MDCT-angiography and two for DSA). Consensus was reached for discordant cases. DSA was considered as the standard of reference.

RESULTS

In 29 patients, 28 aneurysms were found (14 patients had 1 aneurysm, 4 patients had 2 aneurysms and 2 patients had 3 aneurysms; in 9 patients no aneurysm were found). 64MDCT-angiography detected 26/28 aneurysms. No false-positive sites were recognized. The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy were, respectively, 92.8, 100, 100, 99.4 and 99.5%.

CONCLUSIONS

64MDCT-angiography is helpful in detecting intracranial aneurysms with results similar to those of DSA but with less discomfort and risks for the patients and can be considered for the first line imaging technique. Conventional angiography is still needed in doubtful cases or negative MDCT-angiography associated with a strong clinical suspect.

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

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

Repeated digital substraction angiography after perimesencephalic subarachnoid hemorrhage?

BACKGROUND AND PURPOSE

In patients with perimesencephalic subarachnoid hemorrhage (pSAH) DSA is recommended to exclude aneurysms to due false negative findings in CT-angiography. However, whether a second DSA is indicated during the clinical course to exclude--in addition to aneurysms--fistulas, too, is still under debate. We aimed to evaluate the benefit of repeated DSA in patients with pSAH.

METHODS

The source of data was a prospective database set up at the neurological, neurosurgical and neuroradiological departments in our institution. A total of 69 patients with pSAH were enrolled and analyzed by reviewing the medical records and neuroradiological findings.

RESULTS

68 patients presented with Hunt & Hess Grade I-II and one patient with Hunt & Hess Grade III. Median in-hospital stay was 8 days (3-22). In 2 patients mild vasospasm were diagnosed. DSA was performed in all patients at least once. DSA was repeated in 38 patients (55%) after a median of 7 (3-21) days. None of the repeated DSA did show any additional distinctive features with respect to the first DSA.

CONCLUSIONS

In our opinion the procedure of repeating DSA in patients with pSAH is likely to become obsolete. One DSA should be performed prior to discharge--and subsequent to possible vasospasm--to exclude hemorrhage caused by aneurysms of the posterior circulation mimicking a perimesencephalic SAH pattern.

Aneurysmal subarachnoid haemorrhage in pregnancy

Although uncommon, aneurysmal subarachnoid haemorrhage (SAH) in pregnancy can be devastating for both mother and baby. It is the leading cause of other indirect maternal death in England and Wales accounting for 60 deaths in the decade 1988-1999. No single obstetric or neurosurgical unit has sufficiently large database or experience in managing this condition in pregnancy. With significant improvements in antenatal care and management of deliveries, non-obstetric causes of maternal death such as aneurysmal subarachnoid haemorrhage are likely to become increasingly significant. The clinical features of aneurysmal subarachnoid haemorrhage closely resemble those of other commoner conditions seen in pregnancy. It is therefore imperative that awareness by obstetricians and other frontline staff is increased so that a high index of suspicion is maintained when pregnant women present with unique headaches. Prompt neurosurgical referral is vital and early involvement of an experienced neuroradiologist essential. It is only when an early diagnosis is made and an aggressive treatment instituted that the bleak case-fatality figure associated with aneurysmal subarachnoid haemorrhage in pregnancy can be improved. This review, by a multidisciplinary and multicenter team, provides a comprehensive update on the epidemiology, aetiology, clinical presentation, diagnosis and the complexities of the multidisciplinary management of this serious and potentially fatal condition when it occurs in pregnancy.

Untreated subarachnoid hemorrhage: who, why, and when?

OBJECT

When subarachnoid hemorrhage (SAH) is caused by an aneurysm or other vascular anomaly, surgery or endovascular treatment is generally indicated. Nevertheless, some patients with SAH do not receive such therapy. The objective of this study was to characterize the patients who do not receive treatment.

METHODS

The records of all patients with SAH who were admitted to a tertiary care center during a 9-year period were retrospectively reviewed. Untreated patients were classified into one of three groups based on angiographic results. Demographic, clinical, and neuroimaging findings and outcomes were compared between these three groups and between treated and untreated patients. Definitive treatment of SAH was provided in 477 patients and 166 were untreated. Untreated patients were older, had a worse neurological status on presentation, and a higher mortality rate (43.4% compared with 11.7%). Among these, 76 had normal angiographic results and a low mortality rate (6.6%). Fifty-two patients in whom no cerebral angiogram was obtained (mostly because of their neurological condition) had the highest mortality rate (92.3%). Of 38 patients with abnormal angiographic results 50% died, mostly due to rebleeding. Among elderly patients or those with a severe neurological deficit, outcome was significantly better in the ones who were treated.

CONCLUSIONS

A significant proportion of patients who were admitted with SAH did not receive definitive therapy. Major reasons for this included normal results on angiographic studies and poor clinical grade. Untreated patients with normal angiographic results had a good outcome, whereas those in whom angiography was not performed and those with abnormal angiographic results had a high mortality rate from the consequences of the initial hemorrhage in the first instance or rebleeding in the second. Although among elderly patients and those with a poor clinical grade the mortality rate was lower among those who received treatment, a definitive conclusion favoring treatment in these high-risk groups can only be drawn from a prospective randomized study.

“Occult” ruptured cerebral aneurysms revealed by repeat angiography: result from a large retrospective study

Not infrequently, cerebral angiography performed immediately after the onset of subarachnoid hemorrhage (SAH) fails to reveal any causative lesion. Although the cause of the SAH in most of these cases remains unknown, repeat angiography sometimes discloses a lesion not detected by the initial angiography. The frequency of finding a ruptured aneurysm by repeat angiography and the angiographic characteristics of such aneurysms have been investigated retrospectively. Nineteen among 316 non-traumatic SAH patients (6%) showed initially negative angiogram, and 7 of 19 patients (36%) were identified as harboring an "initially occult" aneurysm. It was possible to identify the expected cause of these initial false-negative angiograms in four of those seven patients. The aneurysm was located in the anterior communicating artery (ACoA) complex in four of the seven patients. When interpreting the angiograms of patients with SAH, neurologists and neurosurgeons should bear in mind the finding that the ACoA complex is the most frequent site of "initially occult" aneurysms. One patient had a dissecting aneurysm of the internal carotid artery, and although such lesions have been considered rare, they should be included in the differential diagnosis of SAH of unknown origin.

Non-Aneurysmal Perimesencephalic Subarachnoid Haemorrhage with Associated Pontine Haemorrhagic Infarction

Non-aneurysmal perimesencephalic subarachnoid saemorrhage is characterized by an accumulation of blood in the perimesencephalic and prepontine cisterns identified on sectional imaging together with persistently negative cerebral angiography. Magnetic resonance imaging usually contributes no further information on the possible cause of the bleed but may occasionally show further features including associated parenchymal infarcts such as the pontine haemorrhagic infarct seen in the case described here.

Subarachnoid hemorrhage of unknown origin and the basilar artery configuration

It is unclear whether the configuration of the basilar artery (BA) in patients with subarachnoid hemorrhage (SAH) of unknown origin is comparable to that in normal subjects or whether there are differences which may help to identify the origin. We studied the BA configuration in 57 patients with SAH of unknown origin (10%), who were identified in a prospectively collected series of 549 SAH patients consecutively admitted to our service over a 9-year period. There were 30 patients (53%) with non-perimesencephalic SAH and 27 with perimesencephalic SAH (47%). According to a standardized algorithm we determined, on straight anteroposterior digital subtraction angiography (DSA), the width of the proximal BA segment at the origin of the anterior inferior cerebellar artery and the width of the most distal BA segment between the superior cerebellar arteries and the posterior cerebral arteries. Based on these measurements we calculated the distal-proximal BA ratios and compared them to the ratios obtained in a control group of 31 patients who had DSA for reasons other than aneurysmal SAH. The mean ratio in patients with non-perimesencephalic SAH of unknown origin was 1.150 (range: 1.080-1.230). In patients with perimesencephalic SAH of unknown origin it was 1.156 (range: 1.120-1.250). In the control group the mean ratio was 1.163 (range: 1.125-1.200). There are no variations in the configurations of the BA which could possibly explain the cause of this type of SAH or clarify the origin of hemorrhage.

Three dimensional digital subtraction angiography imaging of a ruptured aneurysm on the anterior communicating artery

BACKGROUND

Although angiography is still gold standard for the diagnosis of cerebral aneurysms, false-negative angiograms in cases of subarachoid hemorrhage due to a rupture of an anterior communicating artery aneurysm have been previously reported. We now report a case of an anterior communicating aneurysm demonstrated by 3-dimensional digital angiography (3D-DSA) after a negative standard angiogram.

CASE DESCRIPTION

A 41-year-old female was admitted in a comatose state. Computed tomography (CT) revealed intraventricular hemorrhage and a clot in the frontal interhemispheric fissure, suggestive of rupture of an anterior communicating artery aneurysm. Two days later, angiography was performed. Although standard 3-vessel angiogram with multiple views, using cross-compression on each carotid artery, was negative, 3D-DSA revealed an anterior communicating aneurysm. The aneurysm was successfully clipped based on the findings obtained from the 3D-DSA. The outcome was favorable, with mild memory disturbance.

CONCLUSION

The standard angiogram sometimes fails to demonstrate aneurysms, especially those on the anterior communicating artery. In this case, 3D-DSA was useful for the diagnosis of the anterior communicating aneurysm which was not seen on standard angiogram.

Diagnosis of perimesencephalic nonaneurysmal subarachnoid hemorrhage with computed tomography

OBJECTIVE

In 4% to 31% of patients with acute subarachnoid hemorrhage (SAH), no underlying cause is identified. Blood is restricted to the perimesencephalic cisterns in about two thirds of these patients. These patients are identified as having perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH), a syndrome based on the interpretation of computed tomography (CT) findings on admission, with an excellent prognosis, far better than other patients with SAH with or without an aneurysm. However, the diagnosis is subject to interrater variability, and differentiation between PNSAH and ruptured supratentorial aneurysm by means of CT has not been investigated. Therefore we investigated the validity of prediction of PNSAH with CT scan.

METHODS

A total of 303 consecutive patients, admitted within 72 hours after the initial bleeding with symptoms and signs of spontaneous SAH, which was confirmed by CT or spectrophotometric analysis of the cerebrospinal fluid (CSF) in whom either a selective 4-vessel angiogram (n = 293) or postmortem examination (n = 10) was performed, were studied.

RESULTS

We found an interrater agreement for the diagnosis perimesencephalic nonaneurysmal subarachnoid hemorrhage of 93% and a kappa value of 0.65. Sensitivity was 30% for observer 1 and 46% for observer 2. The positive predictive value was 73% for observer 1 and 76% for observer 2. Among those diagnosed as having PNSAH, we found vertebrobasilar artery aneurysms in 19% (both raters) and internal carotid artery aneurysms in 5% (observer 1) and 8% (observer 2).

CONCLUSION

We conclude that PNSAH can be distinguished on CT in the majority of patients; however, the angiographical management in PNSAH should not differ from other SAHs.

Subarachnoid haemorrhage following spinal anaesthesia in an obstetric patient

We describe an obstetric patient who presented for removal of a retained placenta. After insertion of the spinal anaesthetic, she developed a severe headache, and a subarachnoid haemorrhage was diagnosed. We discuss the differential diagnosis of the headache, the occurrence of intracranial haemorrhages after dural puncture and the future management of this patient.

Quadrigeminal variant of perimesencephalic nonaneurysmal subarachnoid hemorrhage

OBJECTIVE

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) is a benign entity with a low risk of rebleeding. The most widely accepted definition emphasizes the presence of blood ventral to the midbrain or pons on early computed tomography. We sought to determine the frequency of PNSH with blood centered in the quadrigeminal cistern.

METHODS

We reviewed a prospectively collected database of all patients admitted to our institution over a 2.5-year period with subarachnoid hemorrhage (SAH) and identified PNSH patients from early computed tomographic scans and negative four-vessel angiograms.

RESULTS

Of 220 SAH patients, we identified 9 with PNSH. Two (22%) of these patients had SAH centered in the quadrigeminal cistern without pretruncal blood, negative repeat angiograms, and an uncomplicated clinical course.

CONCLUSION

Quadrigeminal SAH is a variant of PNSH that is not well described in the literature. It may comprise up to one-fifth of PNSH cases and carries a similar benign prognosis.