Cerebellar border zone infarcts are often associated with presumed cardiac sources of ischaemic stroke

Borderzone infarction and recurrent stroke in intracranial atherosclerosis

BACKGROUND

Intracranial stenosis (ICAS) is a common cause of stroke worldwide and patients with symptomatic ICAS exhibit a high rate of recurrence, particularly in the early period after the initial event. In this study, we aimed to study the association between borderzone infarct and recurrent ischemic stroke in patients hospitalized with symptomatic ICAS.

METHODS

This is a retrospective single center study that included patients hospitalized with acute ischemic stroke in the setting of intracranial stenosis (50% or more and an acute ischemic stroke in the territory supplied by the stenosed artery) over a 32-month period. We excluded patients who did not receive a brain MRI or did not have an infarct on brain imaging. The primary predictor is infarct pattern (any borderzone vs. no borderzone infarct) and the primary outcome was recurrent cerebrovascular events (RCVE) within 90 days. We used unadjusted, and age and sex adjusted logistic regression models to determine associations between infarct pattern and RCVE at 90-days.

RESULTS

Among 99 patients who met the inclusion criteria (4 tandem), the mean age was 70.1 ± 11.2 years and 41.4% were women; 43 had borderzone infarcts and 19 had RCVE. In adjusted binary logistic regression analysis, borderzone infarct was associated with increased risk of RCVE (adjusted OR 4.00 95% CI 1.33-11.99, p=0.013). The association between borderzone infarction and RCVE was not different among anterior circulation ICAD (adjusted HR 2.85 95% CI 0.64-12.76, p=0.172) vs. posterior circulation ICAD (adjusted HR 6.69 95% CI 1.06-42.11, p=0.043), p-value for interaction = 0.592.

CONCLUSION

In real world post-SAMMPRIS medically treated patients with ICAD, the borderzone infarct pattern was associated with 90-day RCVE. Borderzone infarcts are likely a surrogate marker of impaired distal blood flow, highlighting the importance of targeting stroke mechanisms and developing alternative treatment strategies for high-risk cohorts.

Cerebral Infarction Observed on Brain MRI in Unconscious Out-of-Hospital Cardiac Arrest Survivors: A Pilot Study

BACKGROUND

Cumulative evidence regarding the use of brain magnetic resonance imaging (MRI) for predicting prognosis of unconscious out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM) is available. Theoretically, these patients are at a high risk of developing cerebral infarction. However, there is a paucity of reports regarding the characteristics of cerebral infarction in this population. Thus, we performed a pilot study to identify the characteristics and risk factors of cerebral infarction and to evaluate whether this infarction is associated with clinical outcomes.

METHODS

A single-center, retrospective, registry-based cohort study was conducted at Severance Hospital, a tertiary center. Unconscious OHCA survivors were registered and treated with TTM between September 2011 and December 2015. We included patients who underwent brain MRI in the first week after the return of spontaneous circulation. We excluded patients who underwent any endovascular interventions to focus on "procedure-unrelated" cerebral infarctions. We assessed hypoxic-ischemic encephalopathy (HIE) and procedure-unrelated cerebral infarction separately on MRI. Patients were categorized into the following groups based on MRI findings: HIE (-)/infarction (-), infarction-only, and HIE (+) groups. Conventional vascular risk factors showing p < 0.05 in univariate analyses were entered into multivariate logistic regression. We also evaluated if the presence of this procedure-unrelated cerebral infarction lesion or HIE was associated with a poor clinical outcome at discharge, defined as a cerebral performance category of 3-5.

RESULTS

Among 71 unconscious OHCA survivors who completed TTM, underwent MRI, and who did not undergo endovascular interventions, 14 (19.7%) patients had procedure-unrelated cerebral infarction based on MRI. Advancing age [odds ratio (OR) 1.11] and atrial fibrillation (OR 5.78) were independently associated with the occurrence of procedure-unrelated cerebral infarction (both p < 0.05). There were more patients with poor clinical outcomes at discharge in the HIE (+) group (88.1%) than in the infarction-only (30.0%) or HIE (-)/infarction (-) group (15.8%) (p < 0.001). HIE (+) (OR 38.69, p < 0.001) was independently associated with poor clinical outcomes at discharge, whereas infarction-only was not (p > 0.05), compared to HIE (-)/infarction (-).

CONCLUSIONS

In this pilot study, procedure-unrelated cerebral infarction was noted in approximately one-fifth of unconscious OHCA survivors who were treated with TTM and underwent MRI. Older age and atrial fibrillation might be associated with the occurrence of procedure-unrelated cerebral infarction, and cerebral infarction was not considered to be associated with clinical outcomes at discharge. Considering that the strict exclusion criteria in this pilot study resulted in a highly selected sample with a relatively small size, further work is needed to verify our findings.

Small obliquely oriented cortical cerebellar infarctions are associated with cardioembolic stroke

Background

A revised classification of cerebellar infarctions (CI) may uncover unrecognized associations with etiologic stroke subtypes. We hypothesized that obliquely oriented small cortical cerebellar infarction (SCCI) representing end zone infarctions on MRI would be associated with cardiac embolism.

Methods

We retrospectively analyzed consecutive stroke patients recruited between January–December 2016 in our center. Analyzed baseline characteristics: sex, age, cardiovascular risk factors, history of stroke or atrial fibrillation (AF). TOAST classification was used for determining stroke subtype. Acute infarction location (anterior/posterior/mixed anterior-posterior circulation), acute uni- or multiterritorial infarction, and acute or chronic CI/SCCI/non-SCCI were assessed by MRI, and vertebrobasilar stenosis/occlusion by vessel imaging. Pre-specified analysis was also performed in patients without known high cardioembolic risk (known AF history or acute multiterritorial infarction).

Results

We included 452 patients (CI in 154, isolated SCCI in 55, isolated non-SCCI in 50, and mixed SCCI/non-SCCI in 49). Both SCCI and non-SCCI were associated with AF history (SCCI, p = 0.021; non-SCCI, p = 0.004), additional acute posterior circulation infarction (p < 0.001 both CI-subtypes), multiterritorial infarctions (SCCI, p = 0.003; non-SCCI, p < 0.001) and cardioembolic more frequent than large-artery atherosclerosis origin (p < 0.001 for both CI-subtypes). SCCI was associated with older age (p < 0.001), whereas non-SCCI was associated with stroke history (p = 0.036) and vertebrobasilar stenosis/occlusion (p = 0.002). SCCI were older (p = 0.046) than non-SCCI patients, had less frequently prior stroke (p < 0.001), and more frequent cardioembolic infarction (p = 0.025).

In patients without known high cardioembolic risk (n = 348), SCCI was strongly associated with subsequent cardioembolism diagnosis (OR 3.00 [CI 1.58–5.73, p < 0.001]). No such association was present in non-SCCI.

Conclusions

Acute or chronic SCCI are strongly associated with a cardioembolic origin.

The Usefulness of the TOAST Classification and Prognostic Significance of Pyramidal Symptoms During the Acute Phase of Cerebellar Ischemic Stroke

Cerebellar stroke is a rare condition with very nonspecific clinical features. The symptoms in the acute phase could imitate acute peripheral vestibular disorders or a brainstem lesion. The aim of this study was to assess the usefulness of the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification in cerebellar stroke and the impact of clinical features on the prognosis. We retrospectively analyzed 107 patients with diagnosed ischemic cerebellar infarction. We studied the clinical features and compared them based on the location of the ischemic lesion and its distribution in the posterior interior cerebellar artery (PICA), superior cerebellar artery (SCA), and anterior inferior cerebellar artery (AICA) territories. According to the TOAST classification, stroke was more prevalent in atrial fibrillation (26/107) and when the lesion was in the PICA territory (39/107). Pyramidal signs occurred in 29/107 of patients and were more prevalent when the lesion was distributed in more than two vascular regions (p = 0.00640). Mortality was higher among patients with ischemic lesion caused by cardiac sources (p = 0.00094) and with pyramidal signs (p = 0.00640). The TOAST classification is less useful in assessing supratentorial ischemic infarcts. Cardioembolic etiology, location of the ischemic lesion, and pyramidal signs support a negative prognosis.

[Cerebellar infarction]

Cerebellar infarction can be difficult to diagnose because the clinical picture is often dominated by fairly non-specific symptoms, which are more indicative of a benign condition. When cerebellar infarction affects the brainstem, the semiology is richer, and pure cerebellar signs are rendered less important. A perfect knowledge of the organisation of the cerebellar artery territories is required, regardless of the infarct topography. This knowledge is essential for making an accurate diagnosis, understanding the mechanisms and organising a treatment plan. Clinical algorithms for the treatment of dizziness, headaches and vomiting would improve the selection of candidates for brain imaging. Thus, the early identification of patients with a high risk of subsequent deterioration would lead to a better prognosis in cases of cerebellar artery territory infarction.

Neuro-otological findings in patients with very small (border zone) cerebellar infarcts

CONCLUSIONS

The symptoms and signs in patients with very small (border zone) cerebellar infarcts (VSCIs) may mimic those in benign peripheral vestibular disorders, except that smooth pursuit eye movement is disturbed in patients with VSCI.

OBJECTIVES

VSCIs are located at the boundary territories between well-defined cerebellar arteries and are frequently manifested by dizziness or vertigo. The aim of the current study was to clarify the clinical characteristics of vestibular symptoms and signs associated with VSCI.

PATIENTS AND METHODS

We studied the neuro-otological findings in five vertiginous patients, who were diagnosed as having VSCI based on magnetic resonance imaging (MRI).

RESULTS

Four patients complained of only dizziness or only vertigo, and one complained of dizziness with dysarthria. Horizontal spontaneous nystagmus and saccadic eye movement on eye tracking test were observed in all patients, but there were no abnormalities on examinations for saccade, optokinetic pattern, or visual suppression. Canal paresis was present in three patients.

Helical CT for the diagnosis of extracranial internal carotid artery dissection

BACKGROUND AND PURPOSE

We attempted to evaluate the sensitivity of helical CT for the diagnosis of extracranial internal carotid artery (ICA) dissection.

METHODS

Sixteen consecutive patients with 18 angiographically confirmed extracranial ICA dissections were studied with a helical CT protocol with large-volume acquisition and thin axial slice reconstructions. A control group including normal and atherosclerotic ICAs was formed for comparison, and a blind interpretation of CT images was made by two observers. We evaluated the presence of stenosis, eccentric lumen, mural thickening, aneurysm, occlusion, and annular contrast enhancement. When the artery seemed to be occluded, we measured the external diameter of the ICA (1) on the occluded side, at its upper portion and most enlarged level, (2) at its lower portion, beyond the bulb, and (3) on the contralateral side, at is upper portion.

RESULTS

Interobserver agreement was good except for the presence of annular contrast enhancement. In the stenotic dissection group (n=12), the presence of a narrowed eccentric lumen at the upper portion of the ICA on axial CT images was classified correctly in all cases (sensitivity, 100%; specificity, 100%). An arterial wall thickening was seen in all cases of dissection but also in three cases of the control group. In the occlusive dissection group (n=6), the enlargement of the dissected artery was the best criterion (sensitivity, 100%, specificity, 100%) for occlusive dissection.

CONCLUSIONS

Helical CT seems to be a reliable method for evaluating extracranial ICA dissection. The analysis of the residual arterial lumen and the measurement of the external diameter of the carotid artery were the best criteria for the diagnosis. Further studies with larger groups are required to determine whether ICA dissections might be diagnosed using helical CT as a first procedure.