Intracranial collateral circulation and its role in neurovascular pathology

Association between cerebral artery stenosis and depressive symptoms in elderly patients

OBJECTIVE

To examine the association between cerebral artery stenosis and depressive symptoms in elderly patients.

METHODS

The study participants were 365 patients aged ≥65 years who visited the psychiatric outpatient clinic, Samsung Medical Center between January 1, 2000, and December 31, 2019, and were diagnosed with depressive disorder. They had brain imaging tests including magnetic resonance angiography (MRA), psychological evaluations including the 15-item Geriatric Depression Scale (GDS-15), and lab tests. Individuals' cerebral artery stenosis was identified and the association with significant depressive symptoms was examined.

RESULTS

Of the 365 subjects, 108 had at least one location of cerebral artery stenosis (29.6 %). The mean score of GDS-15 in the stenosis group was 8.1 (SD, 3.8), higher than the mean GDS-15 score of 6.5 (SD, 4.0) for the group without stenosis (p < 0.001). Compared to no middle cerebral artery (MCA) stenosis, having MCA stenosis was associated with significant depressive symptoms (p = 0.005). Compared to no posterior cerebral artery (PCA) stenosis, having left PCA stenosis was associated with significant depressive symptoms (p = 0.022). In the multivariable linear regression analysis, only bilateral MCA stenosis had a positive association with the score of GDS-15 (p = 0.013).

CONCLUSION

Bilateral MCA stenosis and left PCA stenosis are associated with significant depressive symptoms among elderly patients, with bilateral MCA stenosis positively associated with the severity of depression.

The Spectrum of Intracranial Arteriopathies and Ischemic Strokes in Pediatric Tubercular Meningitis: A Tricentric Study From Eastern India

INTRODUCTION

Addressing the need to uniformly classify arteriopathies among patients with arterial ischemic stroke (AIS) due to tubercular meningitis (TBM), we used the Childhood AIS Standardised Classification and Diagnostic Evaluation (CASCADE) criteria.

METHODS

This tri-centric prospective study included children aged 0.5-12 years with TBM and AIS. Magnetic resonance angiographies (MRAs) were done during admission and repeated 3 and 12 months after discharge. Arteriopathies were classified according to the primary CASCADE criteria. We used the modified Pediatric Alberta Stroke Programme Early Computed Tomography Score as an ordinal measure of infarct volume. The severity of arteriopathies was graded using the focal cerebral arteriopathy severity score (FCASS). The final outcomes were measured at the 12-month follow-up visit using the Pediatric Stroke Outcome Measure (PSOM).

RESULTS

Out of 55 patients, 64% had MRA-evidenced arteriopathies and 84% had multiple infarcts. The middle cerebral (46%) and internal carotid arteries (22%) were most commonly affected. The basal ganglia (70%) and the cerebral cortex (61%) were most commonly infarcted. CASCADE categories included 3b (40%), 1d (38%), 2b (16%), 2c (5%), progressive (32%), and stable (44%) arteriopathies. Younger age, hypertrophic pachymeningitis, cortical infarcts, recurrent strokes, progressive arteriopathies, EEG abnormalities, and mortality were significantly higher among patients with MRA-proven arteriopathies. Patients with progressive arteriopathies had a significantly higher prevalence of hypertrophic pachymeningitis, cortical infarcts, and recurrent strokes. FCASS correlated positively with outcomes measured by the Pediatric Stroke Outcome Measure and modified Pediatric Alberta Stroke Programme Early Computed Tomography Score.

CONCLUSION

The CASCADE classification clarified the arteriopathy patterns, enabling us to correlate them with the characteristics of the infarcts. FCASS is useful to grade the arteriopathy severity and progression in TBM.

The Pathophysiology of Collateral Circulation in Acute Ischemic Stroke

Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called "penumbra". Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.

Longitudinal evaluation of the functional connectivity changes in the secondary somatosensory cortex (S2) of the monkey brain during acute stroke

Background

Somatosensory deficits are frequently seen in acute stroke patients and may recover over time and affect functional outcome. However, the underlying mechanism of function recovery remains poorly understood. In the present study, progressive function alteration of the secondary somatosensory cortex (S2) and its relationship with regional perfusion and neurological outcome were examined using a monkey model of stroke.

Methods and materials

Rhesus monkeys (n = 4) were induced with permanent middle cerebral artery occlusion (pMCAo). Resting-state functional MRI, dynamic susceptibility contrast perfusion MRI, diffusion-weighted, T₁ and T₂ weighted images were collected before surgery and at 4-6, 48, and 96 h post stroke on a 3T scanner. Progressive changes of relative functional connectivity (FC), cerebral blood flow (CBF), and CBF/Tmax (Time to Maximum) of affected S2 regions were evaluated. Neurological deficits were assessed using the Spetzler approach.

Results

Ischemic lesion was evidently seen in the MCA territory including S2 in each monkey. Relative FC of injured S2 regions decreased substantially following stroke. Spetzler scores dropped substantially at 24 h post stroke but slightly recovered from Day 2 to Day 4. Relative FC progressively increased from 6 to 48 and 96 h post stroke and correlated significantly with relative CBFand CBF/Tmax changes.

Conclusion

The present study revealed the progressive alteration of function connectivity in S2 during acute stroke. The preliminary results suggested the function recovery might start couple days post occlusion and collateral circulation might play a key role in the recovery of somatosensory function after stroke insult. The relative function connectivity in S2 may provide additional information for prediction of functional outcome in stroke patients.

Collaterals and Elusive Ischemic Penumbra

As alternative blood supply routes, collateral blood vessels can play a crucial role in determining patient outcomes in acute and chronic intracranial occlusive diseases. Studies have shown that increased collateral circulation can improve functional outcomes and reduce mortality, particularly in those who are not eligible for reperfusion therapy. This article aims to discuss the anatomy and physiology of collateral circulation, describe current imaging tools used to measure collateral circulation, and identify the factors that influence collateral status.

Management of Internal Carotid Artery Injury During Transsphenoidal Surgery: A Case Series and Suggestion for Optimal Management

OBJECTIVE

Internal carotid artery (ICA) injury during transsphenoidal surgery is a rare but serious complication. We analyzed a series of ICA injuries that occurred during a transsphenoidal approach to suggest an optimal management strategy.

METHODS

Between January 2015 and May 2020, we enrolled 10 cases of ICA injury at our institution.

RESULTS

Among the 10 patients enrolled, 5 had pituitary adenoma, 2 had craniopharyngioma, and 1 each had skull base chondrosarcoma, tuberculum sellae meningioma, and nasopharyngeal cancer; 4 were revision surgery cases. The cavernous segment of the ICA was the most commonly injured area. The most common reason for ICA injury was a drill injury at the sellar floor opening. A direct repair was performed using a clip in only 1 patient. In the others, bleeding control of the injured ICA was achieved by packing multiple cotton pads. After angiography, 6 patients underwent immediate endovascular sacrifice of the injured ICA. In 3 patients who showed poor collateral flow from the anterior communicating and posterior communicating arteries, revascularization surgery was performed before endovascular trapping. After 6 postoperative months, 6 patients showed favorable functional outcomes, and 4 patients showed poor functional outcomes.

CONCLUSIONS

Prompt control of bleeding, endovascular management of injured ICA, and consideration of revascularization surgery based on collateral flow may prevent catastrophic neurological sequelae.