Clinical and imaging features in different inner border-zone infarct patterns

Existence and Significance of Internal Border Zone Infarcts with Accessory Lesions Located in the Anteromedial Temporal Lobe

OBJECTIVES

To examine the existence and significance of internal border zone (IBZ) infarcts with accessory lesions in the anteromedial temporal lobe (ATL).

MATERIALS AND METHODS

IBZ infarcts located at the corona radiata were selected based on diffusion-weighted imaging of 2535 consecutive patients with ischemic stroke and the presence of lesions in the ATL was identified. The Mann-Whitney U test, Student t-test, Pearson χ² test, or Fisher exact test was used to analyze differences between the IBZ infarct groups with and without accessory lesions in the ATL.

RESULTS

Thirty-six of 2535 patients (1.4%) had IBZ infarcts. The IBZ group with accessory lesions in the ATL (17 cases, 47.2%) showed a higher portion of occluded middle cerebral arteries than the IBZ group without accessory lesions in the ATL (p = 0.02). The initial National Institutes of Health Stroke Scale score (odds ratio, 2.03; 95% confidence interval, 1.04-3.99;   = 0.039) and progression after admission (odds ratio, 25.43; 95% confidence interval, 2.47-261.99; p = 0.007) were independently associated with poor prognosis in patients with IBZ infarcts. There were no differences in the progression rate and clinical outcomes, regardless of the presence of lesions in the ATL.

CONCLUSIONS

Our study suggests the existence of a distinct type of IBZ infarct characterized by accessory lesions in the ATL, which is associated with different arterial features but has a similar clinical course to IBZ infarcts without accessory lesions in the ATL.

Cerebral border zone infarction: an etiological study

Background

Border zone infarcts (BZI) are ischemic lesions at the junction between two main arterial territories which may be either cortical or internal BZI.

Methods

This study was conducted on 76 cerebral BZI patients and 20 healthy control subjects. Patients were divided to group I included 26 internal BZI, group II included 19 cortical BZI and group III included 21 mixed internal/cortical BZI patients. Included subjects were submitted to neurological examination, laboratory investigations, ECG, echocardiogram, brain CT and/or MRI and extra and intracranial blood vessels imaging by duplex and CT angiography.

Results

Hypertension was significantly higher among groups I and III compared to group II while atrial fibrillation (AF) was significantly higher in groups II and III than group I (p < 0.05). Sonographic duplex assessment of extra and intracranial blood vessels revealed significant increase in mean flow velocities of CCA, ICC and MCA on both side in groups I and III compared to group II (p < 0.05). CT angiography revealed non-significant differences between BZI patients and control as well as in between the three BZI patient's groups regarding the existence of vertebral artery hypoplasia and/or circle of Willis anomalies.

Conclusions

Vascular stenosis is the main etiological factor in internal BZI while AF is the predominant etiological factor of cortical BZI. Congenital vascular anomalies play roles in the localization of BZI but cannot predispose to it except when comorbid with hemodynamic disturbances.

Cerebral Perforating Artery Disease : Characteristics on High-Resolution Magnetic Resonance Imaging

PURPOSE

Our aims were to evaluate the feasibility of high-resolution magnetic resonance imaging (HR-MRI) for displaying the cerebral perforating arteries in normal subjects and to discuss the value of HR-MRI for detecting the causes of infarctions in the territory of the lenticulostriate artery (LSA).

METHODS

Included in this study were 31 healthy subjects and 28 patients who had infarctions in the territory supplied by the LSA. The T1-weighted imaging (T1WI), T2WI, diffusion-weighted imaging (DWI), and HR-MRI, including 3‑dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and 3D fast spin-echo T1WI (namely CUBE T1 in GE Healthcare), were applied on a 3-Tesla scanner. The numbers and route of the perforating arteries on both sides were independently confirmed on HR-MRI by two physicians. The Wilcoxon test was used to compare the differences.

RESULTS

The numbers of perforating arteries in healthy subjects observed on 3D-TOF-MRA were as follows: numbers of the bilateral recurrent artery of Heubner (RAH) ranged from 0-3 (median 1), numbers of the left LSA ranged from 0-7 (median 3), numbers of the right LSA ranged from 0-5 (median 3), numbers of the bilateral anterior choroidal artery ranged from 1-2 (median 1) and the numbers of the bilateral thalamoperforating artery ranged from 1-2 (median 1). In the patients with lenticulostriate infarctions, the numbers of LSAs on the affected side were lower than on the opposite and ipsilateral sides in the healthy subjects. The results were statistically significant. An abnormality of the RAH may lead to a centrum semiovale infarct pattern, whereas an abnormality of the LSA is associated with a corona radiata infarct pattern.

CONCLUSION

The use of HR 3D-TOF-MRA and CUBE T1 had unique advantages in displaying the tiny perforating arteries in vivo. Moreover, effective recognition of the associated cerebral perforating artery and infarct patterns may enhance our understanding of the mechanism of stroke in patients with lenticulostriate infarctions.