Perimesencephalic hemorrhage and CT angiography: A decision analysis

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.

Current status of perimesencephalic non-aneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a distinctive disease, representing SAH centered in perimesencephalic cisterns, with negative angiography findings. In recent years, the number of patients with PNSAH has increased significantly; however, the knowledge of PNSAH is insufficient. Therefore, we performed a review of the literature from a PubMed search and recounted our understanding of PNSAH. In this review, we summarized that current high-resolution computed tomography angiography is an acceptable replacement for digital subtraction angiography to rule out aneurysms in PNSAH with strict criteria. The current hypothesis about the etiology of PNSAH is that there is deep vein rupture from aberrant venous anatomy and increased intracranial venous pressure. PNSAH is associated with mild symptoms and lower rates of hydrocephalus and symptomatic vasospasm. For PNSAH, conservative treatment has been the mainstream treatment. PNSAH has a benign clinical course and an excellent prognosis; in long-term follow-up, re-bleeding and death were uncommon.

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.

The role of imaging in the management of non-traumatic subarachnoid hemorrhage: a practical review

The purpose of this review is to understand the role of imaging in the diagnosis and management of non-traumatic subarachnoid hemorrhage (SAH). SAH is a life-threatening emergency and a relatively common entity, the most common etiology being ruptured aneurysms. Multiple conundrums exist in literature at various steps of its imaging workup: diagnosis, management, and follow-up. We target our review to highlight the most effective practice and suggest efficient workup plans based on literature search, and describe in detail the clinical diagnostic and prognostic scales, role of CT scan, lumbar puncture, and MR, including angiography in the diagnosis and workup of SAH and its complications, and try to simplify the conundrums. Practical knowledge of imaging workup of SAH can help guide correct management of these patients, so as to reduce morbidity and mortality without resource overutilization.

Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm

The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.

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.

Ten Years' Experiences in the Treatment of Nonaneurysmal Subarachnoid Hemorrhage: A Retrospective Analysis of Outcome Parameters in a Single-Center Study

Objectives:

Subarachnoid hemorrhage (SAH) with negative angiographic findings has a heterogeneous nature with variations in clinical course and outcome as compared to the aneurysmal SAH. It makes up to 15% of the spontaneous SAH and is characterized by milder clinical presentation. The purpose of this study was the analyses of risk factors, clinical observations, radiologic characteristics, and outcome in patients with nonaneurysmal SAH (NA-SAH).

Patients and Methods:

In a retrospective design, 77 consecutive patients with NA-SAH were recruited from May 2008, to October 2018. All patients underwent conventional cerebral angiography. We stratified patients into two groups based on the distribution of blood on their CT scan into perimesencephalic (PM) and non-PM (NPM) SAH. We performed the Outcome using Glasgow Coma Scale (GCS) and modified Rankin scale (favorable mRS 0–2 vs. unfavorable mRS 3–6). Data were analyzed using IBM^® SPSS^® Statistics V22.0.

Results:

The mean age at presentation was 48.5 ± 8.4 years with male predominance (71.4%). About 76.7% of the patients had headache and vomiting, most of the patients (75.3%) presented with GCS 15 at initial clinical presentation (61.03%) had NPM versus (38.96%) with PM characters in computed tomography scans. Fourteen (17.9%) patients developed hydrocephalus and 12 (15.3%) needed external ventricular drain placement, while none of the patients needed permanent shunt placement. However, all patients had a favorable clinical and functional outcome at discharge and at late follow-up (up to 3 months).

Conclusions:

NA-SAH does not affect the short- and long-term prognosis. In our results, the pattern of bleeding affects the initial presentation, clinical course, and complications. The clinical and functional outcomes in the majority of our patients were comparable in both groups with good prognosis. Hypertension, smoking, and elevated venous pressure, such as a history of deep venous thrombosis and asthma might be considered as a risk factor.

[The role of interventional neuroradiology in treatment of hemorrhagic stroke]

Treatment of hemorrhagic strokes necessitates hospitalization in an accommodated hospital offering the possibility of a multidisciplinary approach. In this setting, over recent years interventional radiology has become increasingly important from the diagnostic as well as the therapeutic standpoint. In the context of subarachnoid hemorrhage by intracranial aneurysm rupture, the NICE (National Institute for Health and Clinical Excellence) and ASA (American Stroke Academy) recommendations suggest that endovascular coiling should be considered as an alternative to surgical clipping (class I, level of evidence B). As stenting is associated with increased morbidity and mortality in the ruptured aneurysms, it should be avoided (class III, level of evidence C). The patient's clinical status on presentation should be taken into account when deciding on therapeutic management and determining prognosis. Long-term clinical outcome depends on several factors: clinical status on arrival, comorbidities, age, occurrence of operative complications and complications of subarachnoid hemorrhage such as hydrocephaly, vasospasm and delayed cerebral ischemia, as well as complications stemming from prolonged bed rest. In the event of vasospasm refractory to maximal medical therapy, endovascular treatment by intra-arterial injection of Nimodipine and angioplasty can be envisioned. In the event of intracerebral hemorrhage (ICH) by rupture cerebral dural arteriovenous fistula, once the diagnosis has been confirmed, and given the exceedingly high risk of rebleeding, first-line treatment will consist in emergency endovascular embolization. In the event of intracerebral hemorrhage (ICH) by arteriovenous rupture, treatment is decided on during a multidisciplinary meeting and either carried out immediately or delayed according to several factors: clinical conditions, age of the patient, angioarchitecture and ICH location.

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.

Recurrent Bleeding After Perimesencephalic Hemorrhage

BACKGROUND

Perimesencephalic hemorrhage (PMH) is a type of subarachnoid hemorrhage with excellent long-term outcomes. Only 1 well-documented case of in-hospital rebleeding after PMH is described in the literature, which occurred after initiating antithrombotic treatment because of myocardial ischemia. We describe a patient with PMH without antithrombotic treatment who had 2 episodes of recurrent bleeding on the day of ictus. To validate the radiologic findings, we conducted a case-control study. Six neuroradiologists and 2 neuroradiology fellows performed a blinded assessment of serial unenhanced head computed tomography (CT) scans of 8 patients with a perimesencephalic bleeding pattern (1 index patient, 6 patients with PMH, 1 patient with perimesencephalic bleeding pattern and basilar artery aneurysm) to investigate a potential increase in amount of subarachnoid blood.

CASE DESCRIPTION

A 56-year-old woman with a perimesencephalic bleeding pattern and negative CT angiography had 2 episodes after the onset headache with a sudden increase of the headache. Blinded assessment of serial head CT scans of 8 patients with a perimesencephalic bleeding pattern identified the patient who was clinically suspected to have 2 episodes of recurrent bleeding to have an increased amount of subarachnoid blood on 2 subsequent CT scans.

CONCLUSIONS

Recurrent bleeding after PMH may also occur in patients not treated with antithrombotics. Even after early rebleeding, the prognosis of PMH is excellent.

Cerebrovascular Imaging: Which Test is Best?

Optimal diagnosis and characterization of cerebrovascular disease requires selection of the appropriate imaging exam for each clinical situation. In this review, we focus on intracranial arterial disease and discuss the techniques in current clinical use for imaging the blood vessel lumen and blood vessel wall, and for mapping cerebral hemodynamic impairment at the tissue level. We then discuss specific strategies for imaging intracranial aneurysms, arteriovenous malformations, dural arterial venous fistulas, and arterial steno-occlusive disease.

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.

Epidemiological Features of Nontraumatic Spontaneous Subarachnoid Hemorrhage in China: A Nationwide Hospital-based Multicenter Study

BACKGROUND

Nontraumatic spontaneous subarachnoid hemorrhage (SAH) is associated with a high mortality. This study was conducted to investigate the epidemiological features of nontraumatic spontaneous SAH in China.

METHODS

From January 2006 to December 2008, the clinical data of patients with nontraumatic SAH from 32 major neurosurgical centers of China were evaluated. Emergent digital subtraction angiography (DSA) was performed for the diagnosis of SAH sources in the acute stage of SAH (≤3 days). The results and complications of emergent DSA were analyzed. Repeated DSA or computed tomography angiography (CTA) was suggested 2 weeks later if initial angiographic result was negative.

RESULTS

A total of 2562 patients were enrolled, including 81.4% of aneurysmal SAH and 18.6% of nonaneurysmal SAH. The total complication rate of emergent DSA was 3.9% without any mortality. Among the patients with aneurysmal SAH, 321 cases (15.4%) had multiple aneurysms, and a total of 2435 aneurysms were detected. The aneurysms mostly originated from the anterior communicating artery (30.1%), posterior communicating artery (28.7%), and middle cerebral artery (15.9%). Among the nonaneurysmal SAH cases, 76.5% (n = 365) had negative initial DSA, including 62 cases with peri-mesencephalic nonaneurysmal SAH (PNSAH). Repeated DSA or CTA was performed in 252 patients with negative initial DSA, including 45 PNSAH cases. Among them, the repeated angiographic results remained negative in 45 PNSAH cases, but 28 (13.5%) intracranial aneurysms were detected in the remaining 207 cases. In addition, brain arteriovenous malformation (AVM, 7.5%), Moyamoya disease (7.3%), stenosis or sclerosis of the cerebral artery (2.7%), and dural arteriovenous fistula or carotid cavernous fistula (2.3%) were the major causes of nonaneurysmal SAH.

CONCLUSIONS

DSA can be performed safely for pathological diagnosis in the acute stage of SAH. Ruptured intracranial aneurysms, AVM, and Moyamoya disease are the major causes of SAH detected by emergent DSA in China.

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.

Imaging of Nontraumatic Neuroradiology Emergencies

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

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.

The negative predictive value of CT angiography in the setting of perimesencephalic subarachnoid hemorrhage

Background

Perimesencephalic subarachnoid hemorrhage (PMSAH) is only rarely associated with a ruptured cerebral aneurysm and CT angiography (CTA) has very good sensitivity and specificity for aneurysm detection. The necessity for invasive imaging with digital subtraction angiography (DSA) is therefore debatable. We chose to assess the negative predictive value (NPV) of CTA in a series of patients with PMSAH treated at our institution over a 9-year period.

Methods

We retrospectively assessed the diagnostic yield of DSA after initial negative CTA in patients with a PMSAH pattern defined as blood centered anterior to the midbrain and/or pons within the pre-pontine or interpeduncular cistern with possible quadrigeminal or ambient cistern extension; possible extension into the basal parts of the sylvian fissures but not the lateral sylvian fissures; possible extension to the cisterna magna but not centered on the cisterna magna; and possible extension into the fourth ventricle and occipital horns of the lateral ventricles.

Results

Using this definition of PMSAH, of 72 patients, one patient showed a potentially significant finding on DSA that was not demonstrated on initial CTA (NPV 98.61% (95% CI 92.47% to 99.77%)). However, when cisterna magna extension was excluded from the definition of PMSAH, no false negative CTAs in 56 patients were encountered (NPV 100% (95% CI 93.56% to 100.00%)).

Conclusions

The NPV of normal CTA for an arterial abnormality in patients with PMSAH is high and our results therefore question the role of invasive imaging. The findings also suggest that a prospective study designed to clarify the necessity of performing DSA in this population would be feasible.

Nonaneurysmal perimesencephalic subarachnoid hemorrhage: diagnosis, pathophysiology, clinical characteristics, and long-term outcome

Patients with nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPSAH) have no discernible source for the bleeding and generally are considered to have a benign condition. Correctly diagnosing these patients is essential because a missed aneurysm can have catastrophic consequences. Those presenting with NAPSAH have a low risk of complications and better outcome than patients presenting with aneurysmal subarachnoid hemorrhage; however, a limited body of literature suggests that not all of these patients are able to return to their premorbid functional status. Clinical screens of cognitive status, such as the mini-mental status examination, suggest good recovery of these patients, although these tests may lack sensitivity for identifying deficits in this patient population. More comprehensive neuropsychologic testing in some studies has identified deficits in a wide range of cognitive domains at long-term follow-up in patients with NAPSAH. Because these patients often do not lose consciousness (and thus do not have substantial transient global ischemia) and they do not undergo a procedure for aneurysm repair, the cognitive sequelae can be explained by the presence of blood in the subarachnoid space. NAPSAH presents an opportunity to understand the effects of subarachnoid blood in a clinical setting.

Non-aneurysmal non-traumatic subarachnoid hemorrhage: patient characteristics, clinical outcome and prognostic factors based on a single-center experience in 125 patients

BACKGROUND

Subarachnoid hemorrhage (SAH) is mainly caused by ruptured cerebral aneurysms but in up to 15% of patients with SAH no bleeding source could be identified. Our objective was to analyze patient characteristics, clinical outcome and prognostic factors in patients suffering from non-aneurysmal SAH.

METHODS

From 1999 to 2009, data of 125 patients with non-aneurysmal SAH were prospectively entered into a database. All patients underwent repetitive cerebral angiography. Outcome was assessed according to the modified Rankin Scale (mRS) (mRS 0-2 favorable vs. 3-6 unfavorable). Also, patients were divided in two groups according to the distribution of blood in the CT scan (perimesencephalic and non-perimesencephalic SAH).

RESULTS

106 of the 125 patients were in good WFNS grade (I-III) at admission (85%). Overall, favorable outcome was achieved in 104 of 125 patients (83%). Favorable outcome was associated with younger age (P < 0.001), good admission status (P < 0.0001), and absence of hydrocephalus (P = 0.001).73 of the 125 patients suffered from perimesencephalic SAH, most patients (90%) were in good grade at admission, and 64 achieved favorable outcome.52 of the 125 patients suffered from non-perimesencephalic SAH and 40 were in good grade at admission. Also 40 patients achieved favorable outcome.

CONCLUSIONS

Patients suffering from non-aneurysmal SAH have better prognosis compared to aneurysm related SAH and poor admission status was the only independent predictor of unfavorable outcome in the multivariate analysis. Patients with a non-perimesencephalic SAH have an increased risk of a worse neurological outcome. These patients should be monitored attentively.

Subarachnoid hemorrhage: beyond aneurysms

OBJECTIVE

Spontaneous subarachnoid hemorrhage (SAH) typically prompts a search for an underlying ruptured saccular aneurysm, which is the most common nontraumatic cause. Depending on the clinical presentation and pattern of SAH, the differential diagnosis may include a diverse group of causes other than aneurysm rupture.

CONCLUSION

For the purposes of this review, we classify SAH into three main patterns, defined by the distribution of blood on unenhanced CT: diffuse, perimesencephalic, and convexal. The epicenter of the hemorrhage further refines the differential diagnosis and guides subsequent imaging. Additionally, we review multiple clinical conditions that can simulate the appearance of SAH on CT or MRI, an imaging artifact known as pseudo-SAH.

De novo aneurysm of the anterior communicating artery presenting with subarachnoid hemorrhage 7 years after initial cryptogenic subarachnoid hemorrhage: a case report and review of the literature

Spontaneous subarachnoid hemorrhage (SAH) is usually caused by a ruptured cerebral aneurysm. Despite the use of initial four-vessel cerebral digital subtraction angiography (DSA), 15 % of all cases remain idiopathic. According to the initial computed tomographic scan, the spontaneous SAH can be divided into a perimesencephalic group associated with a benign nature and a nonperimesencephalic group with a similar clinical course as aneurysmal SAH. We present a case of a 49-year-old man with a de novo aneurysm formation of the anterior communicating artery with SAH 7 years after initial cryptogenic nonperimesencephalic SAH. This observation suggests that in some cases, long-term angiographic studies might be justified.

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.

European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage

BACKGROUND

Intracranial aneurysm with and without subarachnoid haemorrhage (SAH) is a relevant health problem: The overall incidence is about 9 per 100,000 with a wide range, in some countries up to 20 per 100,000. Mortality rate with conservative treatment within the first months is 50-60%. About one third of patients left with an untreated aneurysm will die from recurrent bleeding within 6 months after recovering from the first bleeding. The prognosis is further influenced by vasospasm, hydrocephalus, delayed ischaemic deficit and other complications. The aim of these guidelines is to provide comprehensive recommendations on the management of SAH with and without aneurysm as well as on unruptured intracranial aneurysm.

METHODS

We performed an extensive literature search from 1960 to 2011 using Medline and Embase. Members of the writing group met in person and by teleconferences to discuss recommendations. Search results were graded according to the criteria of the European Federation of Neurological Societies. Members of the Guidelines Committee of the European Stroke Organization reviewed the guidelines.

RESULTS

These guidelines provide evidence-based information on epidemiology, risk factors and prognosis of SAH and recommendations on diagnostic and therapeutic methods of both ruptured and unruptured intracranial aneurysms. Several risk factors of aneurysm growth and rupture have been identified. We provide recommendations on diagnostic work up, monitoring and general management (blood pressure, blood glucose, temperature, thromboprophylaxis, antiepileptic treatment, use of steroids). Specific therapeutic interventions consider timing of procedures, clipping and coiling. Complications such as hydrocephalus, vasospasm and delayed ischaemic deficit were covered. We also thought to add recommendations on SAH without aneurysm and on unruptured aneurysms.

CONCLUSION

Ruptured intracranial aneurysm with a high rate of subsequent complications is a serious disease needing prompt treatment in centres having high quality of experience of treatment for these patients. These guidelines provide practical, evidence-based advice for the management of patients with intracranial aneurysm with or without rupture. Applying these measures can improve the prognosis of SAH.

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

Background

To identify patients with spontaneous subarachnoid hemorrhage for whom CT angiography alone can exclude ruptured aneurysms.

Methods

An 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."

Results

Two 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.

Conclusions

CT 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.

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.

Inter- and intraobserver agreement in CT characterization of nonaneurysmal perimesencephalic subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The perimesencephalic pattern of SAH as seen on unenhanced CT is associated with significantly better outcomes when compared to an aneurysmal pattern of SAH. The aim of this study was to determine the degree of inter- and intraoberver agreement for characterization of the NAPH as seen on unenhanced CT.

MATERIALS AND METHODS

We retrospectively reviewed the CT scans of 37 patients with spontaneous SAH, all of whom had undergone CT within 24 hours of onset of headache symptoms. All patients had undergone conventional cerebral angiography to confirm or exclude aneurysms or other vascular pathology. All 37 cases were angiographically confirmed nonaneurysmal SAHs. Four readers with neuroradiology subspecialty training independently evaluated CT images to characterize the hemorrhage pattern as compatible with the well-described NAPH. Each reader performed a second reading session blinded to the initial readings. The first and second sets of readings were performed approximately 4 months apart. Inter- and intraobserver agreement for characterization of the NAPH was determined by using the kappa statistic.

RESULTS

Of the 37 angiographically confirmed nonaneurysmal SAHs, there was unanimous agreement as to the hemorrhage pattern in 29 (78%) cases and disagreement in 8 (22%) cases. Overall, intraobserver agreement was good (kappa = 0.80). Interobserver agreement was also good (kappa = 0.79).

CONCLUSIONS

Overall, inter- and intraobserver agreement for the NAPH was good. There was, however, a level of disagreement among observers, thus suggesting that clinicians should be cautious when deciding whether to pursue follow-up imaging.

Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed?

BACKGROUND AND PURPOSE

CTA is becoming the frontline modality to reveal aneurysms in patients with SAH. However, in about 20% of SAH patients no aneurysm is found. In these cases, intra-arterial DSA is still performed. Our aim was to evaluate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH.

MATERIALS AND METHODS

We conducted a retrospective analysis of all negative findings on CTAs performed from 2005 to 2009 in patients with spontaneous SAH. Findings were compared with DSA. CTAs were performed with a 64-section multidetector row CT scanner.

RESULTS

One hundred ninety-three patients with SAH and negative findings on CTA who underwent subsequent DSA were identified. The distribution of blood on unenhanced CT was the following: PMH in 93 patients, diffuse aneurysmal pattern in 50, no blood on CT (xanthochromic LP) in 32, and peripheral sulcal distribution in 18. All patients with PMH had negative findings on DSA. One patient with no blood on CT had vasculitis on DSA. Six of 18 (33%) patients with peripheral blood had vasculitis on DSA. Three of these were also diagnosed by CTA. All except 1 patient with diffuse aneurysmal blood had negative findings on DSA. One patient was diagnosed with an aneurysm on DSA (1/50, 0.5%). Repeat delayed DSA performed in 28 of these patients revealed a small aneurysm in 4 (14%). Five patients had a complication of DSA (2.6%); 1 was a clinical stroke (0.5%).

CONCLUSIONS

In patients with SAH, negative CTA findings are reliable in ruling out aneurysms in the PMH pattern or no blood on CT. DSA is indicated in the diffuse aneurysmal pattern of SAH, and repeat delayed DSA is required if the initial DSA findings are negative. When the blood is peripheral, CTA should be scrutinized for vasculitis and DSA is recommended for confirmation.

Management of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Acute aneurysmal subarachnoid hemorrhage (SAH) is a complex multifaceted disorder that plays out over days to weeks. Many patients with SAH are seriously ill and require a prolonged intensive care unit stay. Cardiopulmonary complications are common. The management of patients with SAH focuses on the anticipation, prevention, and management of these secondary complications.

DATA SOURCES

Source data were obtained from a PubMed search of the medical literature.

DATA SYNTHESIS AND CONCLUSION

The rupture of an intracranial aneurysm is a sudden devastating event with immediate neurologic and cardiac consequences that require stabilization to allow for early diagnostic angiography. Early complications include rebleeding, hydrocephalus, and seizures. Early repair of the aneurysm (within 1-3 days) should take place by surgical or endovascular means. During the first 1-2 weeks after hemorrhage, patients are at risk of delayed ischemic deficits due to vasospasm, autoregulatory failure, and intravascular volume contraction. Delayed ischemia is treated with combinations of volume expansion, induced hypertension, augmentation of cardiac output, angioplasty, and intra-arterial vasodilators. SAH is a complex disease with a prolonged course that can be particularly challenging and rewarding to the intensivist.

Occurrence of perimesencephalic subarachnoid hemorrhage during pregnancy

BACKGROUND

Perimesencephalic subarachnoid hemorrhage (P-SAH) is a benign subset of subarachnoid hemorrhage with a favorable prognosis and low rate of re-bleeding. Risk factors may include hypertension and tobacco use, but it has not previously been reported during pregnancy.

METHODS

We report two cases of P-SAH in pregnant women, a 40-year-old female, 8-weeks pregnant and a 37-year-old female at 35 weeks gestational age.

RESULTS

CT scan confirmed P-SAH in both cases. CT angiography in one case and cerebral angiogram in the other did not reveal aneurysm or other potential bleeding source. The patients underwent transcranial Doppler ultrasound monitoring without evidence of vasospasm.

CONCLUSION

P-SAH hemorrhage may occur during early or late pregnancy. We do not propose an increased risk of P-SAH during pregnancy. The clinical course appears favorable and CT angiography alone may be considered the preferred diagnostic test to assess for aneurysm in first trimester pregnancy.

Spontaneous isolated convexity subarachnoid hemorrhage: presentation, radiological findings, differential diagnosis, and clinical course

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

Recurrent perimesencephalic subarachnoid hemorrhage during antithrombotic therapy

INTRODUCTION

In patients with non-aneurysmal perimesencephalic hemorrhage, spontaneous rebleeding does not occur. The lack of reported recurrences may lead to less cautious administration of antithrombotic therapy.

METHODS

Case report.

RESULTS

A 57-year-old woman with a perimesencephalic pattern of hemorrhage and negative CT angiography was treated with carbasalate calcium and intravenous heparin because of an acute coronary syndrome. Three days after installment of this antithrombotic therapy she experienced a recurrent perimesencephalic hemorrhage leading to hydrocephalus and a decrease in consciousness. She died the same day as a result of ventricular fibrillation.

CONCLUSION

In the early phase after perimesencephalic hemorrhage, anticoagulant therapy may lead to rebleeding. The risks and benefits of antithrombotic therapy should be carefully weighed in patients with a perimesencephalic pattern of hemorrhage and negative CT angiography.

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.

Lymphoma and leukemia cells possess fractal dimensions that correlate with their biological features

BACKGROUND

Living cells can be viewed as complex adaptive systems that exhibit non-linear dynamics and fractal features. We investigated the fractal qualities of normal and malignant hematological cells and their potential as a tool for characterizing cell phenotype and clinical behavior.

METHODS

A mathematical algorithm and an optic tool for fractal analysis of nuclei were developed. A total of 4,713 lymphoid cells derived from 66 patients of five distinct diagnostic groups (normal and reactive lymphocytes, low-grade lymphomas and an aggressive lymphoma) were assessed for their fractal dimension. In addition, in 19 patients fractal analysis of leukemia cells was compared to clinical endpoints.

RESULTS

After validating our method, hematological cells possessed fractal dimensions corresponding to their clinical entity. There was a highly significant overall difference in fractal dimensions between various types of hematological malignancies. A preliminary correlation was found between the fractal dimension and the clinical outcome of leukemia patients.

CONCLUSIONS

Hematological cells possess fractal dimensions that correlate with their biological properties. Measurement of fractal dimension seems to be a sensitive method to assess the hematological cell phenotype and to define a clinical group. This tool may be potentially useful for the evaluation of clinical behavior of hematological diseases.

[Non-aneurysmal subarachnoid haemorrhage]

A subarachnoid haemorrhage (SAH) is frequent after a severe head injury. Traumatic-SAH is associated with a bad outcome and may induce cerebral vasospasm. There is no agreement on the treatment based on the amount of traumatic-SAH. Non-aneurysmal SAH accounts for 15% of all causes of non-traumatic SAH. There is a risk of cerebral vasospasm, although less frequent than after aneurysmal rupture. The improvement in imaging techniques has decreased the frequency of idiopathic SAH.

Multislice CT angiography in the selection of patients with ruptured intracranial aneurysms suitable for clipping or coiling

Introduction

We sought to establish whether CT angiography (CTA) can be applied to the planning and performance of clipping or coiling in ruptured intracranial aneurysms without recourse to intraarterial digital subtraction angiography (IA-DSA).

Methods

Over the period April 2003 to January 2006 in all patients presenting with a subarachnoid haemorrhage CTA was performed primarily. If CTA demonstrated an aneurysm, coiling or clipping was undertaken. IA-DSA was limited to patients with negative or inconclusive CTA findings. We compared CTA images with findings at surgery or coiling in patients with positive CTA findings and in patients with negative and inconclusive findings in whom IA-DSA had been performed.

Results

In this study, 224 consecutive patients (mean age 52.7 years, 135 women) were included. In 133 patients (59%) CTA demonstrated an aneurysm, and CTA was followed directly by neurosurgical (n = 55) or endovascular treatment (n = 78). In 31 patients (14%) CTA findings were categorized as inconclusive, and in 60 (27%) CTA findings were negative. One patient received surgical treatment on the basis of false-positive CTA findings. In 17 patients in whom CTA findings were inconclusive, IA-DSA provided further diagnostic information required for correct patient selection for any therapy. Five ruptured aneurysms in patients with a nonperimesencephalic SAH were negative on CTA, and four of these were also false-negative on IA-DSA. On a patient basis the positive predictive value, negative predictive value, sensitivity, specificity and accuracy of CTA for symptomatic aneurysms were 99%, 90%, 96%, 98% and 96%, respectively.

Conclusion

CTA should be used as the first diagnostic modality in the selection of patients for surgical or endovascular treatment of ruptured intracranial aneurysms. If CTA renders inconclusive results, IA-DSA should be performed. With negative CTA results the complementary value of IA-DSA is marginal. IA-DSA is not needed in patients with negative CTA and classic perimesencephalic SAH. Repeat IA-DSA or CTA should still be performed in patients with a nonperimesencephalic SAH.

The radiological investigation of subarachnoid haemorrhage

Subarachnoid haemorrhage is an important condition with a high mortality, so prompt diagnosis is essential. This article will review the investigation of subarachnoid haemorrhage with a radiological bias. Appropriate clinical correlation will be included and it will look at some of the more interesting areas in the investigation of this condition.