Pattern Of Subarachnoid Hemorrhage Research Articles

Subarachnoid Haemorrhage Incidence Pattern Analysis with Circular Statistics.

Knowledge about biological rhythms of diseases may not only help in understanding the pathophysiology of diseases but can also help health service policy makers and emergency department directors to allocate resources efficiently. Aneurysmal subarachnoid haemorrhage (SAH) has high rates of morbidity and mortality. The incidence of SAH has been attributed to patient-related factors such as characteristics of aneurysms, smoking, and hypertension. There are studies showing that the incidence of aneurysmal SAH appears to behave in periodic fashions over long time periods. However, there are inconsistencies in the literature regarding the impact of chronobiological factors such as circadian, seasonal, and lunar cycle factors on the occurrence of SAH. In this study, we focused on the analysis of a temporal pattern of SAH (infradian rhythms) with a novel approach using circular statistical methods. We aimed to see whether there is a circular pattern for the occurrence of SAH at all and if so, whether it can be related to known temporal patterns based on available literature. Our study did not support the notion that aneurysmal subarachnoid haemorrhages occur on any specific day in a cycle with specific lengths up to 365 days including specific weekdays, full moon, equinoxes, and solstices. Hence, we found no relationship between SAH incidence and timing. Study in larger populations using similar circular statistical methods is suggested.

Subarachnoid Hemorrhage: The Incidence and Correlation of CT Pattern and the Location of Cerebral Aneurysm

Background: Subarachnoid hemorrhage has a high mortality and morbidity rates, and the cerebral aneurysm is the most common cause. The location of the ruptured cerebral aneurysm is diagnosed by cerebral angiogram and by computed tomography (CT) pattern of the subarachnoid hemorrhage. Objective: To find the incidence of CT pattern of each cerebral aneurysm and the correlation between CT pattern of subarachnoid hemorrhage and each location of cerebral aneurysm. Materials and Methods: The 126 patients with ruptured cerebral aneurysm were included in the present study. The information of the patients and CT were recorded and analyzed. Results: There were 49 male and 77 female patients. The highest location of cerebral aneurysm is anterior communicating aneurysm (59 patients, 47.6%). There were correlations between A region and anterior cerebral and anterior communicating aneurysm, and left D legion and the other location aneurysm. There were correlations between intracerebral hemorrhage and anterior communication, posterior communication cerebral, and anterior cerebral and middle cerebral artery aneurysm. Conclusion: The common location of cerebral aneurysm is anterior communicating artery aneurysm. There are correlations between the most thickness region of A and D region with anterior communicating aneurysm and the posterior circulation aneurysm, and the correlation between intracerebral hemorrhage and anterior communicating aneurysm, posterior communicating aneurysm, and middle cerebral artery aneurysm. Keywords: Subarachnoid hemorrhage, Cerebral aneurysm, Intracerebral hemorrhage, Thickness

Persistent primitive hypoglossal artery presenting with perimesencephalic nonaneurysmal subarachnoid hemorrhage: A case report and review of literature

BackgroundPersistent primitive hypoglossal artery (PPHA) is a rare remnant of the congenital carotid-basilar artery anastomosis, sometimes associated with subarachnoid hemorrhage (SAH), and aneurysms are the more common cause. However, the association of PPHA with perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is extremely rare. This report is the first to describe the occurrence of PNSAH concerning PPHA. Case descriptionA 53-year-old man suffered from subarachnoid hemorrhage with a sudden severe headache. An emergency brain computed tomography (CT) disclosed a perimesencephalic pattern of SAH. CT angiography (CTA) revealed a right PPHA entering the posterior fossa through the right enlarged hypoglossal canal. No source of the hemorrhage was identified in the imaging examinations, even with the performance of a 4-vessel angiography. ConclusionWe present a case of PPHA associated with PNSAH and review the literature. The main cause for the PPHA related to SAH is an aneurysm. The four vessels angiography helped rule out an aneurysm that is associated with a poorer prognosis and requires immediate active management. It is, therefore, essential for physicians to be aware of the increased incidence of aneurysms in PPHA to make the correct diagnosis.

Prognostic variables and outcome in relation to different bleeding patterns in arteriovenous malformations.

Subarachnoid hemorrhage as bleeding pattern occurs rarely in ruptured arteriovenous malformations (AVM). The aim of the present study is to evaluate different bleeding patterns in hemorrhages due to an AVM and their impact on outcome in terms of risk and treatment stratification. We evaluated 158 patients with ruptured AVMs who were admitted to our neurosurgical department from 2002 to 2017. We compared different bleeding patterns, such as intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), or both (ICH + SAH) and evaluated predictive variables for outcome in the last follow-up. ICH was found in 48.7% of patients, isolated SAH in 20.9% of patients, and both in 30.4% of patients. The mean parenchymal blood volume was 34.5cm3. 38.6% of the patients had AVM-associated aneurysms, mostly located pre-nidal (77%). AVMs with ruptured aneurysms often resulted in ICH with SAH component (p < 0.001) and SAH pattern occurred more often infratentorial (p = 0.003). In a multivariate logistic regression model, poor clinical state on admission (WFNS IV-V) (p < 0.01), eloquence, infratentorial location (p = 0.05), and presence of ICH with SAH component (p = 0.02) were the most relevant predictors of a poor outcome after AVM rupture. Bleeding pattern in AVM hemorrhage depends on angioarchitectural and hemodynamic features and SAH component predicts outcome negatively. AVM-associated pre-nidal aneurysms may harbor a higher risk for rupture and SAH pattern when located infratentorial. Treatment decisions and risk stratifications should be considered in view of these findings.

Digital Subtraction Angiography for CT Angiogram Negative Haemorrhages.

In patients with subarachnoid haemorrhage (SAH) and a negative finding on CT angiography (CTA), further imaging with digital subtraction angiography (DSA) is commonly performed to identify the source of bleeding. The purpose of this study was to investigate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH. This retrospective study identified all DSAs performed between August 2010 and July 2014 within our institution. CT angiography was performed with a 64-section multidetector row CT scanner. Only DSAs from patients with confirmed SAH and a negative CTA result were included in the final analyses. A fellowship-trained neuroradiologist reviewed the imaging results. Of the 857 DSAs, 50 (5.83%) were performed in 35 patients with CTA-negative SAH. Of the 35 patients, three (8.57%) had positive findings on the DSA. In one patient, suspicious dissection of the extra- and intra-cranial segment of the right vertebral artery could not be confirmed even in retrospect. In the second patient, the suspicious finding of tiny protuberance from the left paraclinoid internal carotid artery (ICA) on DSA did not change on follow-up and did not change patient's management. The third patient had a posterior inferior cerebellar artery aneurysm, which was not seen on the initial CTA owing to the incomplete coverage of the head on the CTA. In patients with SAH, negative findings on a technically sound CTA are reliable in ruling out aneurysms in any pattern of SAH or no blood on CT. Our observations need to be confirmed with larger prospective studies.

Nonaneurysmal “Pseudo-Subarachnoid Hemorrhage” Computed Tomography Patterns: Challenges in an Acute Decision-Making Heuristics

Acute aneurysmal subarachnoid hemorrhage (SAH) is a medical and neurosurgical emergency from ruptured brain aneurysm. Aneurysmal SAH is identified on brain computed tomography (CT) as increased density of basal cisterns and subarachnoid spaces from acute blood products. Aneurysmal SAH-like pattern on CT appears as an optical illusion effect of hypodense brain parenchyma and/or hyperdense surrounding cerebral cisterns and blood vessels termed as "pseudo-subarachnoid hemorrhage" (pseudo-SAH). We reviewed clinical, laboratory, and radiographic data of all SAH diagnoses between January 2013 and January 2018, and found subsets of nonaneurysmal SAH, originally suspected to be aneurysmal in origin. We performed a National Library of Medicine search methodology using terms "subarachnoid hemorrhage," "pseudo," and "non-aneurysmal subarachnoid hemorrhage" singly and in combination to understand the sensitivity, specificity, and precision of pseudo-SAH. Over 5 years, 230 SAH cases were referred to our tertiary academic center and only 7 (3%) met the definition of pseudo-SAH. Searching the National Library of Medicine using subarachnoid hemorrhage yielded 27,402 results. When subarachnoid hemorrhage and pseudo were combined, this yielded 70 results and sensitivity was 50% (n = 35). Similarly, search precision was relatively low (26%) as only 18 results fit the clinical description similar to the 7 cases discussed in our series. Aneurysmal SAH pattern on CT is distinct from nonaneurysmal and pseudo-SAH patterns. The origin of pseudo-SAH terminology appears mostly tied to comatose cardiac arrest patients with diffuse dark brain Hounsfield units and cerebral edema, and is a potential imaging pitfall in acute medical decision-making.

Diffuse Patterns of Nonaneurysmal Subarachnoid Hemorrhage Originating from the Basal Cisterns Have Predictable Vasospasm Rates Similar to Aneurysmal Subarachnoid Hemorrhage

Nonaneurysmal subarachnoid hemorrhage (SAH) has been historically associated with a benign clinical course. However, recent studies have suggested that nonaneurysmal SAH can present with different hemorrhage patterns that may be associated with differential rates of morbidity. Herein, we analyze a retrospective consecutive cohort of patients with nonaneurysmal SAH to determine outcomes. We also seek to evaluate a validated radiographic grading scale to determine its utility in predicting vasospasm in the setting of different hemorrhage patterns. After institutional review board approval, the records of 563 consecutive patients admitted with spontaneous SAH between January 2007 and 2014 were retrospectively reviewed. A total of 138 of these patients had no identifiable source of hemorrhage and were further divided into 2 groups depending on their pattern of hemorrhage: perimesencephalic or diffuse. Clinical characteristics and outcomes were assessed. In nonaneurysmal SAH, 70 patients (50.7%) had a perimesencephalic pattern of hemorrhage, whereas 68 (49.3%) experienced diffuse SAH. Radiographic vasospasm developed in 6 patients (8.6%) with perimesencephalic SAH and in 14 patients (20.6%) with a diffuse SAH pattern. When comparing historical rates of vasospasm based on the Barrow Neurological Institute (BNI) scale and rates in the nonaneurysmal diffuse pattern in this series, there was no significant difference in distribution (chi-square; P=.149), compared with a difference seen with the perimesencephalic group (P<.00001). Nonaneurysmal SAH is associated with the potential for vasospasm, with higher rates in the diffuse versus perimesencephalic SAH patterns. The BNI grading scale for aneurysmal SAH can be used to predict the risk of vasospasm in diffuse, nonaneurysmal SAH.

An Analysis of 88 Patients with Diffuse and “Benign” Perimesencephalic Subarachnoid Hemorrhage

Perimesencephalic subarachnoid hemorrhage (PMSAH) was previously defined as a variant of subarachnoid hemorrhage (SAH) associated with a relatively benign clinical presentation and better outcomes than aneurysmal SAH. However, several prior studies have shown complications associated with PMSAH including vasospasm and hydrocephalus, and the need for follow-up imaging. We therefore reviewed our experience to further characterize the clinical consequences of PMSAH. Eighty-eight consecutive patients who sustained spontaneous intracranial SAH and whose cerebral angiograms did not show any obvious source for SAH were retrospectively studied to characterize their prognosis and outcome based on SAH pattern. Glasgow Coma Scale and Hunt-Hess scores on admission, the incidence of vasospasm or hydrocephalus, the need for an external ventricular drain, and shunt dependence, along with Glasgow outcome score (GOS) at discharge and follow-up, were used to draw comparisons between perimesencephalic and diffuse SAH patient populations. Patients with perimesencephalic SAH differed statistically (p < 0.05) from patients with diffuse SAH in regard to age, Hunt-Hess score on presentation, hospital length of stay, GOS at discharge, and incidence of hydrocephalus, angiographic vasospasm, and clinical vasospasm. Our data demonstrate that although the patients with perimesencephalic SAH fared better than those with diffuse SAH, their outcomes were worse than those of similar patients with PMSAH who have been previously reported in the literature.

Diagnostic yield of delayed neurovascular imaging in patients with subarachnoid hemorrhage, negative initial CT and catheter angiograms, and a negative 7 day repeat catheter angiogram

PurposeThe yield of delayed neurovascular imaging in patients with subarachnoid hemorrhage (SAH), negative initial CT and catheter angiograms (CT angiography (CTA), DSA), and negative 7 day repeat DSA is not...

Abstract TP213: Ischemic And Hemorrhagic Stroke In Patients With Implantation Of Left Ventricular Assist Device

Background and Purpose: Stroke is one of the major complications in patients implanted with left ventricular assist device (LVAD). In Japan, the duration waiting for a heart transplant from a LVAD implantation is beyond 800 days. While antithrombotic therapy is often aggressively given, hemorrhagic stroke as well as ischemic one is a major complication that determines the outcome in these patients. However, the type of stroke in patients with LVAD implantation has not been fully investigated. The purpose of this study is to clarify the type and characteristic of acute stroke with LVAD implantation by using CT findings. Methods: Between 2005 and 2011, we reviewed 110 consecutive cases underwent LVAD implantation. Among them, 49 cases (126 events in total) suffered from the acute stroke at least once. We analyzed the category, the sites of lesions and the CT findings of each acute stroke events. Results: Among 49 acute stroke cases (5-74 yr old, 16 female and 33 male), brain infarction (n=39, 71 events), brain hemorrhage(n=25, 31 events) and subarachnoid hemorrhage (SAH) (n=23, 33 events) were identified. Thus, the incidence of hemorrhagic stroke is equal to that of ischemic stroke in patients with LVAD. In 71 infarct events, CT showed the lesion in the cortex (n=44), in the basal ganglia (n=17) and in the brain stem and cerebellum (n=17). Multiple infarctions were also observed in 29 events. In brain hemorrhage events (n=31), almost all were identified in the subcortical lesion (n=27), and none was seen in the basal ganglia. Hemorrhage in the infratentorial area (n=3) and intraventricular space (n=1) were rare. In SAH (n=33), we identified hemorrhage located only in one sulcus in 25 events. We tentatively called this small characteristic pattern of SAH “petite SAH”. Furthermore, in 12 events of “petite SAH”, fresh cortical infarction was simultaneously observed in CT. Conclusions: CT findings of acute stroke after implantation of left ventricular assist device are characteristically multifocal cortical lesions, regardless of brain infarction and hemorrhage. Although the mechanisms underlying petite SAH are unknown, prevention and management of ischemic as well as hemorrhagic stroke is undoubtedly important to improve the outcome of patients with LVAD implantation.

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

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. 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. 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. 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.

Abstract 3282: Diagnostic Yield of Repeat CT Angiography in Patients with Subarachnoid Hemorrhage and Negative Initial CT and Catheter Angiograms

Purpose: To determine the yield of repeat CT angiography for the detection of causative vascular lesions in patients with subarachnoid hemorrhage (SAH) who have negative initial CT and catheter angiograms. Methods: We conducted a retrospective review of patients who presented to our institution between January 1st, 2008 and August 1st, 2011 with SAH and negative initial CT and catheter angiograms who were examined with repeat CT angiography in order to determine the yield of this imaging modality for the detection of causative vascular lesions. Two experienced neuroradiologists evaluated the NCCTs to determine the pattern of SAH (diffuse, perimesencephalic or peripheral) and the CT angiograms (CTA) to assess for the presence of a causative vascular lesion. All differences in reader interpretation were resolved by consensus. Results: Twenty-two patients were included in our study, with a mean age of 78 years (median 59 years, range 28-78 years). Sixteen patients were male (72.7%) and 6 female (27.3%). Seventeen patients had diffuse SAH (77.3%), 4 perimesencephalic SAH (18.2%) and 1 peripheral SAH (4.5%). Mean time interval between the initial neurovascular examination and the repeat CTA was 26.5 days (median 20.5 days, range 2-150 days). The repeat CTA demonstrated a causative vascular lesion in 2 patients (9.1%), all of which had diffuse SAH (yield of 11.8%). The vascular lesions identified were 1 small pontine arteriovenous malformation and a 2-mm supraclinoid internal carotid artery aneurysm ( Figure ). The pontine arteriovenous malformation underwent radiosurgery and the internal carotid artery aneurysm underwent surgical clipping. In retrospect, none of these vascular lesions were evident in the initial CT or catheter angiograms. Conclusion: Repeat CT angiography is valuable in the evaluation of patients with diffuse SAH who have negative initial CT and catheter angiograms, demonstrating a causative vascular lesion in 11.8% of patients.

Abstract 49: Diagnostic Yield of Catheter Angiography in Patients with Subarachnoid Hemorrhage and Negative Initial Non-Invasive Neurovascular Examinations

Purpose: To determine the yield of catheter angiography for the detection of causative vascular lesions in patients with subarachnoid hemorrhage (SAH) who have a negative initial non-invasive neurovascular examination. Methods: Between January 1st, 2006 and August 1st, 2011, we instituted a prospective protocol by which patients who presented to our institution with SAH and had a negative initial non-invasive neurovascular examination (CT or MR angiogram [CTA, MRA]) were examined with catheter angiography to detect causative vascular lesions. Two experienced neuroradiologists evaluated the NCCTs to determine the pattern of SAH (diffuse, perimesencephalic or peripheral) and the catheter angiograms to assess for the presence of a causative vascular lesion. All differences in reader interpretation were resolved by consensus. Results: Forty-eight patients were included in our study, with a mean age of 58 years (median 59 years, range 25-84 years). Twenty-six patients were male (54.2%) and 22 female (45.8%). Twenty-eight patients had diffuse SAH (58.3%), 11 peripheral SAH (22.9%) and 9 perimesencephalic SAH (18.8%). The initial non-invasive neurovascular examination was a CTA in 41 patients (85.4%) and an MRA in 7 patients (14.6%). A second catheter angiogram was performed in 30 patients (62.5%). Mean time interval between the initial non-invasive neurovascular examination and the first catheter angiogram was 0.9 days (median 1 day, range 0-7 days) and the second catheter angiogram was 12.2 days (median 8.5 days, range 4-69 days). Catheter angiography demonstrated a causative vascular lesion in 4 patients (8.3%), 3 of which had diffuse SAH (yield of 10.7%) and 1 had peripheral SAH (yield of 9.1%). Of note, 1 of the causative vascular lesions was identified in a second catheter angiogram performed 8 days after the CTA in a patient with diffuse SAH. The vascular lesions identified were 2 dural arteriovenous fistulas, 1 pial cerebellopontine angle arteriovenous malformation with a 2-mm feeding artery aneurysm located in the internal auditory canal ( Figure ), and a 3-mm anterior communicating artery aneurysm. Two of the vascular lesions underwent endovascular embolization, 1 radiosurgery and 1 endovascular embolization followed by radiosurgery. In retrospect, the vascular lesion could be seen in the initial examination in 2 patients. Conclusion: Catheter angiography is a valuable tool in the evaluation of patients with diffuse and peripheral SAH who have a negative initial non-invasive neurovascular examination, demonstrating a causative vascular lesion in 10.7% and 9.1% of patients, respectively.

Abstract 3456: Incidence of Vasospasm and Outcomes in Angiography-negative Perimesencephalic Subarachnoid Hemorrhage with and without Ventricular Extension

Background: Angiography negative perimesencephalic subarachnoid hemorrhage (SAH) is considered a relatively benign entity compared to aneurysmal SAH. However, some patients with angiography negative perimesencephalic subarachnoid hemorrhage with extension of hemorrhage beyond the perimesencephalic area are at increased risk for vasospasm. Here we present a series of 21 patients with angiography negative perimesencephalic pattern of SAH both with and without ventricular extension and describe their incidence of vasospasm and clinical outcomes. Methods: Retrospective chart review was performed among patients who underwent invasive angiography from 8/2007-6/2010. Inclusion criteria were presenting clinical symptoms typical of SAH, computed tomography (CT) evidence of perimesencephalic SAH with or without ventricular extension, no recent trauma or stroke, and cerebral angiography negative for aneurysm or arteriovenous malformation. 21 patients, 8 men and 13 women, with a mean age of 55.1 years met these criteria. The presenting CTs were examined and a modified Fisher Grade assigned. The patients’ clinical course was reviewed for incidence and treatment of vasospasm. The patients’ discharge summaries were evaluated and each patient given a modified Rankin Scale score. Results: The modified Fisher Scale score derived from the presenting CT was 1 for 29% (n=6), 2 for 5% (n=1), 3 for 19% (n=4), and 4 for 47% (n=10) of the patients. Amongst the 52% (n=11) of patients with intraventricular hemorrhage as defined by a modified Fisher Scale score of 2 or 4, 24% (n=5) developed angiographical evidence of vasospasm. 10% (n=2) of the patients required intra-arterial verapamil. 90% (n=9) of patients without intraventricular extension had good outcomes at discharge as defined by modified Rankin Scale score less than or equal to 2, while only 36% (n=4) of patients with angiography negative SAH with intraventricular extension had good outcomes. Conclusions: Although angiography negative perimesencephalic SAH is considered to have less associated morbidity and mortality than aneurysmal perimesencephalic SAH, patients with extension of hemorrhage into the ventricles are at increased risk for vasospasm and poor functional outcomes.

Bilateral Vertebral Artery Dissecting Aneurysms Presenting with Subarachnoid Hemorrhage Treated by Staged Coil Trapping and Covered Stents Graft

The treatment of bilateral vertebral artery dissecting aneurysms (VADAs) presenting with subarachnoid hemorrhage (SAH) is still challenging. The authors report a rare case of bilateral VADA treated with coil trapping of ruptured VADA and covered stents implantation after multiple unsuccessful stent assisted coiling of the contralateral unruptured VADA. A 44-year-old woman was admitted to our hospital because of severe headache and sudden stuporous consciousness. Brain CT showed thick SAH and intraventricular hemorrhage. Cerebral angiography demonstrated bilateral VADA. Based on the SAH pattern and aneurysm configurations, the right VADA was considered ruptured. This was trapped with endovascular coils without difficulty. One month later, the contralateral unruptured VADA was protected using a stent-within-a-stent technique, but marked enlargement of the left VADA was detected by 8-months follow-up angiography. Subsequently two times coil packing for pseudosacs resulted in near complete occlusion of left VADA. However, it continued to grow. Covered stents graft below the posterior inferior cerebellar artery (PICA) origin and a coronary stent implantation across the origin of the PICA resulted in near complete obliteration of the VADA. Covered stent graft can be used as a last therapeutic option for the management of VADA, which requires absolute preservation of VA flow.

Subarachnoid Hemorrhage of Unknown Etiology along the Cortical Convexity

Only 8% to 22% of cases of subarachnoid hemorrhage (SAH) are of nonaneurysmal origin. Among these, perimesencephalic nonaneurysmal SAH is a distinct clinical and radiologic entity with normal angiographic findings and a good prognosis. In contrast, SAH of nonaneurysmal origin occurring along the cortical convexity is rare and poorly understood. We report 2 cases of subarachnoid hemorrhage along the cortical convexity and discuss their possible etiologies. In a retrospective analysis of 234 patients with SAH, we identified 2 patients with a typical computed tomographic pattern of convexity SAH that was associated with no known etiology. In these 2 cases, the source of hemorrhage could not be identified with computed tomography, magnetic resonance imaging, or digital subtraction angiography, although neurovascular outcomes were good. The patients reported such incidents as coughing or exertion immediately before headache developed. These incidents may have caused increased intracranial pressure. We suggest the possible involvement of a brief increase in intracranial pressure, such as that accompanying coughing or exertion, in the occurrence of SAH along the cortical convexity.

Subarachnoid Hemorrhage with Negative Baseline Digital Subtraction Angiography: Is Repeat Digital Subtraction Angiography Necessary?

IntroductionPatients 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.MethodsA 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.ResultsOf 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.ConclusionIn 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.

Cerebral aneurysm exclusion by CT angiography based on subarachnoid hemorrhage pattern: a retrospective study

BackgroundTo identify patients with spontaneous subarachnoid hemorrhage for whom CT angiography alone can exclude ruptured aneurysms.MethodsAn observational retrospective review was carried out of all consecutive patients with non-traumatic subarachnoid hemorrhage who underwent both CT angiography and catheter angiography to exclude an aneurysm. CT angiography negative cases (no aneurysm) were classified according to their CT hemorrhage pattern as "aneurismal", "perimesencephalic" or as "no-hemorrhage."ResultsTwo hundred and forty-one patients were included. A CT angiography aneurysm detection sensitivity and specificity of 96.4% and 96.0% were observed. All 35 cases of perimesencephalic or no-hemorrhage out of 78 CT angiography negatives also had negative angiography findings.ConclusionsCT angiography is self-reliant to exclude ruptured aneurysms when either a perimesencephalic hemorrhage or no-hemorrhage pattern is identified on the CT within a week of symptom onset.

CRANIAL MIGRATION OF A BACLOFEN PUMP CATHETER ASSOCIATED WITH SUBARACHNOID HEMORRHAGE

Cephalad migration of an indwelling intrathecal catheter within the spinal canal has rarely been described. Cranial subarachnoid hemorrhage (SAH) related to movement of this type of catheter has not been described. We report a case of SAH coincident with the migration of a free fragment of a baclofen pump catheter into the prepontine cistern. A baclofen pump system was removed from a 47-year-old man with spasticity related to multiple sclerosis. A section retained in the spinal canal extended up to the T9 level. Ten days after the pump and lower portion of the catheter were removed, the patient presented with a severe headache and a classic aneurysmal pattern of SAH. The patient's catheter was found to have migrated adjacent to the basilar artery at the level of the superior cerebellar artery. An extensive evaluation, including computed tomography angiography, digital subtraction angiography performed twice, magnetic resonance imaging, and magnetic resonance angiography, showed no apparent cause for the hemorrhage. Initially, the catheter was left in place. However, 5 months after the SAH, the patient elected to have the catheter removed. The catheter was pulled out from below through a C6-C7 laminoplasty without complications. The patient made an excellent recovery. Cephalad catheter migration is a rare phenomenon. The mechanism of rostral migration remains unclear. The forces that propel a free fragment of catheter under these circumstances seem to be sufficient to cause a small vessel to rupture and bleed. Given the lack of an observed arterial injury, we postulate that venous bleeding caused this hemorrhage.

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

In an era in which new computed tomographic scanners approach 100% sensitivity for finding intracranial aneurysms in patients with a perimesencephalic subarachnoid hemorrhage (SAH) pattern, digital subtraction angiography (DSA) is still considered the gold standard. Our purpose was to investigate whether or not computed tomography angiographic (CTA) scanning can be used as the sole diagnostic tool in this setting, and thus replace DSA. Two hundred fifty patients with atraumatic SAH presented to our institute between November 2001 and November 2005. We performed a retrospective search for those patients who had a negative brain CTA scan for aneurysms. Of these, those with a computed tomographic scan showing perimesencephalic SAH at admission were selected, and only those who had DSA performed were included. We found 30 patients with negative brain CTA scans that matched the perimesencephalic SAH pattern and had DSA performed. The mean time for performing a brain CTA scan was 3.8 +/- 4.4 days, and for DSA 11 +/- 12 days, after the initiation of symptomatology. The interval between CTA and DSA was 5.9 +/- 15 days. There were two patients in whom CTA was considered negative but still suspicious for having an aneurysm; DSA was negative for both. Brain CTA scanning alone is a good and conclusive diagnostic tool to rule out aneurysms in patients presenting with the classic perimesencephalic SAH pattern and thus can replace DSA and its corresponding risks. The latter can be reserved for those patients in whom CTA is doubtful.