Neuroradiologic Diagnosis of Minor Leak prior to Major SAH: Diagnosis by T1-FLAIR Mismatch

Should individual timeline and serial CT/MRI panels of all patients be presented in acute brain insult cohorts? A pilot study of 45 patients with decompressive craniectomy after aneurysmal subarachnoid hemorrhage

PURPOSE

Our review of acute brain insult articles indicated that the patients' individual (i) timeline panels with the defined time points since the emergency call and (ii) serial brain CT/MRI slice panels through the neurointensive care until death or final brain tissue outcome at 12 months or later are not presented.

METHODS

We retrospectively constructed such panels for the 45 aneurysmal subarachnoid hemorrhage (aSAH) patients with a secondary decompressive craniectomy (DC) after the acute admission to neurointensive care at Kuopio University Hospital (KUH) from a defined population from 2005 to 2018. The patients were indicated by numbers (1.-45.) in the pseudonymized panels, tables, results, and discussion. The timelines contained up to ten defined time points on a logarithmic time axis until death ([Formula: see text]; 56%) or 3 years ([Formula: see text]; 44%). The brain CT/MRI panels contained a representative slice from the following time points: SAH diagnosis, after aneurysm closure, after DC, at about 12 months (20 survivors).

RESULTS

The timelines indicated re-bleeds and allowed to compare the times elapsed between any two time points, in terms of workflow swiftness. The serial CT/MRI slices illustrated the presence and course of intracerebral hemorrhage (ICH), perihematomal edema, intraventricular hemorrhage (IVH), hydrocephalus, delayed brain injury, and, in the 20 (44%) survivors, the brain tissue outcome.

CONCLUSIONS

The pseudonymized timeline panels and serial brain imaging panels, indicating the patients by numbers, allowed the presentation and comparison of individual clinical courses. An obvious application would be the quality control in acute or elective medicine for timely and equal access to clinical care.

Unrecognized Ruptured Intracranial Aneurysm Presenting as Cerebral Vasospasm-Induced Ischemic Stroke: A Case Report

A 44-year-old woman presented with acute confusion, apparently due to a clinically silent subarachnoid hemorrhage followed by vasospasm, which in turn led to an ischemic stroke. During the initial evaluation, an acute ischemic stroke in the left middle cerebral artery territory was observed. Magnetic resonance imaging revealed a late subacute hemorrhage in the left basal cistern. Digital subtraction angiography indicated the presence of a small saccular aneurysm that had recently ruptured, as well as vasospasm in the left circle of Willis. Balloon angioplasty and balloon-assisted coil embolization were performed for the vasospasm and saccular aneurysm, respectively. This case demonstrates that clinically silent subarachnoid hemorrhages resulting in ipsilateral vasospasm and infarction can occur as complications of a ruptured aneurysm.

Clinical Significance of the CSF Pulsation Flow Sign in the Foramen of Monro on FLAIR in Patients with Aneurysmal SAH -Preliminary Report

It is known that the cerebrospinal fluid (CSF) pulsation flow sign in the lateral ventricles directly above the foramen of Monro (CPF-M) on axial fluid attenuated inversion recovery (FLAIR) is a normal physiological finding as an artifact of FLAIR. In this study, whether CPF-M can be used as a neuroradiological finding related to pathological conditions in patients with acute aneurysmal subarachnoid hemorrhage (aSAH) was investigated. CPF-M-related clinical features were retrospectively evaluated in 147 aSAH patients who underwent adequate serial MRI examinations without massive intraventricular hemorrhage (IVH) of the lateral ventricle within 48 h of ictus. The frequency of the CPF-M in the control group was 32% (57/178), 33% (40/123), and 38% (45/117) for the normal control, chronic cerebral infarction, and deep white matter lesion (WML) groups, respectively. In aSAH patients, the overall prevalence of the CPF-M was 57% (84/147), significantly higher than in the three control groups. Multivariate analysis showed that age <70 years, lower IVH Hijdra score of the fourth ventricle, absence of T₁-FLAIR mismatch, deep WMLs, old infarction, diffuse brain swelling, symptomatic delayed cerebral ischemia (DCI), shunt-dependent chronic hydrocephalus (SDCH), and favorable outcome were significantly associated with the CPF-M. Although limited to SAH patients without massive IVH of the lateral ventricles, one can conclude that, in acute aSAH, the presence of CPF-M on admission MRI suggests that the circulatory dynamics of the CSF from the basal cistern to the ventricles are approximately normal. Thus, this finding may appear to offer an indicator of a good outcome without DCI and SDCH.

Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

The T1 value of pure water, which is often used as a phantom to simulate cerebrospinal fluid, is significantly different from that of in-vivo cerebrospinal fluid. The purpose of this study was to develop a phantom with a T1 value equivalent to that of in-vivo cerebrospinal fluid under examination room temperature (23°C-25°C). In this study, 1.5 and 3.0 T magnetic resonance imaging scanners were used. We examined the signal intensity change in relation to pure water temperature, the T1 values of acetone-diluted solutions (0-100 v/v%, in 10 steps), and the correlation coefficients obtained from volunteers and the prepared phantoms. The T1 value was close to the value reported in the literature for cerebrospinal fluid when the acetone-diluted solution was 70 v/v% or higher at scan room temperature. The value at that time was 3532.81-4704.57 ms at 1.5 T and it ranged from 4052.41 to 5701.61 ms at 3.0 T. The highest correlation with the values obtained from the volunteers was r = 0.993 with pure acetone at 1.5 T and r = 0.991 with acetone 90 v/v% at 3.0 T. The relative error of the best phantom-volunteer match was 32.61 (%) ± 6.71 at 1.5 T and 46.67 (%) ± 4.31 at 3.0 T. The T1 value measured by the null point method did not detect a significant difference between in vivo CSF and acetone 100 v/v% at 1.5 T and acetone 90 v/v% at 3.0 T. The T1 value of cerebrospinal fluid in the living body at scan room temperature was reproduced with acetone. The optimum concentration of acetone for cerebrospinal-fluid reproduction was pure acetone at 1.5 T and 90 v/v% at 3.0 T.

Complementary Roles of Dynamic Contrast-Enhanced MR Imaging and Postcontrast Vessel Wall Imaging in Detecting High-Risk Intracranial Aneurysms

BACKGROUND AND PURPOSE

Individual assessment of the absolute risk of intracranial aneurysm rupture remains challenging. Emerging imaging techniques such as dynamic contrast-enhanced MR imaging and postcontrast vessel wall MR imaging may improve risk estimation by providing new information on aneurysm wall properties. The purpose of this study was to investigate the relationship between aneurysm wall permeability on dynamic contrast-enhanced MR imaging and aneurysm wall enhancement on postcontrast vessel wall MR imaging in unruptured intracranial aneurysms.

MATERIALS AND METHODS

Patients with unruptured saccular intracranial aneurysms were imaged with vessel wall MR imaging before and after gadolinium contrast administration. Dynamic contrast-enhanced MR imaging was performed coincident with contrast injection using 3D T1-weighted spoiled gradient-echo imaging. The transfer constant (K ^trans) was measured adjacent to intracranial aneurysm and adjacent to the normal intracranial artery.

RESULTS

Twenty-nine subjects were analyzed (mean age, 53.9 ± 13.5 years; 24% men; PHASES score: median, 8; interquartile range, 4.75-10). K ^trans was higher in intracranial aneurysms compared with the normal intracranial artery (median, 0.0110; interquartile range, 0.0060-0.0390 versus median, 0.0032; interquartile range, 0.0018-0.0048 min^-1; P < .001), which correlated with intracranial aneurysm size (Spearman ρ = 0.54, P = .002) and PHASES score (ρ = 0.40, P = .30). Aneurysm wall enhancement, detected in 19 (66%) aneurysms, was associated with intracranial aneurysm size and the PHASES score but not significantly with K ^trans (P = .30). Aneurysms of 2 of the 9 patients undergoing conservative treatment ruptured during 1-year follow-up. Both ruptured aneurysms had increased K ^trans, whereas only 1 had aneurysm wall enhancement at baseline.

CONCLUSIONS

Dynamic contrast-enhanced MR imaging showed increased K ^trans adjacent to intracranial aneurysms, which was independent of aneurysm wall enhancement on postcontrast vessel wall MR imaging. Increased aneurysm wall permeability on dynamic contrast-enhanced MR imaging provides new information that may be useful in intracranial aneurysm risk assessment.

On Aneurysmal Rupture and Rerupture

A warning leak is a curious phenomenon attributed to cerebral aneurysms. Once the leak occurs, it has been postulated it could lead to a more catastrophic rebleeding. The designation "warning leak" trickled into neurosurgery vocabulary as early as the 1950s. The phenomenon has been poorly understood and characterized, but its presence spurs emergency physicians and neurointensivists to take action to secure the aneurysm. Rapid treatment of a recently discovered aneurysm is now commonplace, but it has not always been so. Antifibrinolytic agents spawned particular interest in the late 1970s, when many neurosurgeons postponed surgery after a recent hemorrhage. This historical vignette reviews the early views on aneurysmal rupture, rerupture, and the role of fibrinolysis.

Retrospective review of previous minor leak before major subarachnoid hemorrhage diagnosed by MRI as a predictor of occurrence of symptomatic delayed cerebral ischemia

OBJECTIVE

This study attempted to determine whether a previous minor leak correlated with the occurrence of symptomatic delayed cerebral ischemia (sDCI).

METHODS

The authors retrospectively evaluated sDCI-related clinical features and findings from MRI, including T1-weighted imaging (T1WI)–FLAIR mismatch at the time of admission, in 151 patients admitted with subarachnoid hemorrhage (SAH) within 48 hours of ictus.

RESULTS

The overall incidence of sDCI was 23% (35 of 151 patients). In all subjects, multivariate analysis revealed that World Federation of Neurosurgical Societies Grades II–V, age 70 years or older, presence of rebleeding after admission, a previous minor leak before the major SAH attack as diagnosed by T1WI-FLAIR mismatch, acute infarction on diffusion-weighted imaging, and CT SAH score were significantly associated with occurrence of sDCI. In patients with no previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was only 7% (7 of 97 patients).

CONCLUSIONS

A previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch represents an important sDCI-related factor. When the analysis was restricted to patients with true acute SAH without a previous minor leak diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was extremely low.

Unruptured intracranial aneurysms: An updated review of current concepts for risk factors, detection and management

The management of patients with unruptured intracranial aneurysms (UIAs) is a complex clinical challenge and constitutes an immense field of research. While a preponderant proportion of these aneurysms never rupture, the consequences of such an event are severe and represent an important healthcare problem. To date, however, the natural history of UIAs is not completely understood and there is no accurate means to discriminate the UIAs that will rupture from those that will not. Yet, a good understanding of the recent evidence and future perspectives is needed when advising a patient with IA to tailor any information to the given patient's level of risk and psychoaffective status. Thus, this review addresses the current concepts of epidemiology, risk factors, detection and management of UIAs.

Quantitative Susceptibility Mapping as a Possible Tool to Radiographically Diagnose Sentinel Headache Associated with Intracranial Aneurysm: Case Report

BACKGROUND

Sentinel headache (SH) occurs before aneurysm rupture in an estimated 15%-60% of cases of aneurysmal subarachnoid hemorrhage (aSAH). By definition, noncontrast computed tomography (CT) scan of the brain and lumbar puncture are both negative in patients presenting with SH. One of the theories explaining this phenomenon is that microhemorrhage (MH) from the aneurysm wall contribute to iron deposition in the interface between the aneurysm wall and brain parenchyma. Quantitative susceptibility mapping (QSM) is a recently introduced magnetic resonance imaging (MRI) technique that has proven capable of localizing the deposition of paramagnetic metals, particularly ferric iron. Thus, the QSM sequence may be able to detect iron deposition secondary to MH.

CASE DESCRIPTION

A 76-year-old male presented with the "worst headache of my life." Noncontrast head CT scan and lumbar puncture were negative. Magnetic resonance angiography (MRA) of the brain revealed an anterior communicating artery (A-com) aneurysm measuring 7 mm with a large bleb. T1-weighted imaging (WI), T2-WI, MRA, T2 star-weighted angiography (SWAN), and QSM sequences were obtained. T2-WI, SWAN, and QSM revealed isointense, hypointense, and hyperintense signals, respectively, at the interface of the aneurysm wall and brain tissue. These findings were consistent with deposition of ferric iron at this interface. The A-com aneurysm was treated with coil embolization, and the patient exhibited no postoperative deficits.

CONCLUSIONS

The MRI QSM sequence can localize iron deposition resulting from MH within an aneurysmal wall. This sequence may be a promising imaging tool for screening patients presenting with SH.

Effect of Headache on the Pathologic Findings of Unruptured Cerebral Saccular Aneurysms

BACKGROUND

Some patients with aneurysm exhibit warning headaches without minor bleeding, and this could be caused by stretching of the aneurysm wall. Recently, our pathologic study observed subintimal fibrin deposition in a majority of the ruptured aneurysms. However, these findings also were observed in some unruptured aneurysms. In this report, 2 unruptured aneurysms exhibited subintimal fibrin, and interestingly, one of the patients experienced severe headache within 1 month before neuroimaging.

OBJECTIVE

We performed pathologic analysis of unruptured aneurysms and collected their various clinical variables, including severe headache, to clarify the clinical characteristics of "dangerous" unruptured aneurysms.

METHODS

This study included unruptured saccular aneurysm samples (n = 17) that were resected after clipping. We compared the differences in clinical variables, including warning headache, between aneurysms with and without fibrin deposition.

RESULTS

Fibrin deposition was present in the subintimal layer in 4 patients and in the periouter membrane in 4 patients. Three of the 4 former patients experienced warning headaches, and one presented aneurysm growth. Of the latter 4 patients, one exhibited aneurysm growth, whereas the others presented with relatively large aneurysms. In the remaining 9 aneurysms without fibrin deposition, monocyte infiltration was observed in one, all aneurysms were small, and no patients experienced warning headaches or aneurysm growth.

CONCLUSIONS

Subintimal fibrin deposition is observed frequently in patients with aneurysm with warning headaches. These pathologic findings are clinically inspiring and may suggest that these aneurysms exhibit rapid stretching by newly formed aneurysms, which can result in rupture at an early stage.