Transient filament occlusion of the middle cerebral artery in rats: does the reperfusion method matter 24 hours after perfusion?

BACKGROUND: There are two widely used transient middle cerebral artery occlusion (MCAO) methods, which differ in the use of unilateral or bilateral carotid artery reperfusion (UNICAR and BICAR). Of the two methods, UNICAR is easier to perform. This study was designed to comprehensively compare the two reperfusion methods to determine if there are any differences in outcomes. RESULTS: The UNICAR and BICAR groups each included 9 rats. At baseline, the average pO(2) was 20.54 ± 9.35 and 26.43 ± 7.39, for the UNICAR and BICAR groups, respectively (P = 0.519). Changes in pO(2), as well as other physiological parameters measured within the ischemic lesion, were similar between the UNICAR and BICAR groups during 90 min of MCAO and the first 30 min of reperfusion (all P > 0.05). Furthermore, both the Bederson score and Garcia score, which are used for neurological assessment, were also similar (both P > 0.05). There were also no significant differences in T2WI lesion volume, DWI lesion volume, PWI lesion volume, or TTC staining infarct volume between the two groups (all P > 0.05). CONCLUSION: UNICAR and BICAR have similar capability for inducing acute brain ischemic injury and can be considered interchangeable up to 24 hours after reperfusion.

Clinical and radiological differences between patients with probable cerebral amyloid angiopathy and mixed cerebral microbleeds.

BACKGROUND: The key imaging features of cerebral amyloid angiopathy (CAA) are lobar, cortical, or cortico-subcortical microbleeds, macrohaemorrhages and cortical superficial siderosis (cSS). In contrast, hypertensive angiopathy is characterized by (micro) haemorrhages in the basal ganglia, thalami, periventricular white matter or the brain stem. Another distinct form of haemorrhagic microangiopathy is mixed cerebral microbleeds (mixed CMB) with features of both CAA and hypertensive angiopathy. The distinction between the two entities (CAA and mixed CMB) is clinically relevant because the risk of haemorrhage and stroke should be well balanced if oral anticoagulation is indicated in CAA patients. We aimed to comprehensively compare these two entities. METHODS: Patients with probable CAA according to the modified Boston criteria and mixed CMB without macrohaemorrhage were retrospectively identified from our database. Comprehensive comparison regarding clinical and radiological parameters was performed between the two cohorts. RESULTS: Patients with CAA were older (78 ± 8 vs. 74 ± 9 years, p = 0.036) and had a higher prevalence of cSS (19% vs. 4%, p = 0.027) but a lower prevalence of lacunes (73% vs. 50%, p = 0.018) and deep lacunes (23% vs. 51%, p = 0.0003) compared to patients with mixed CMB. Logistic regression revealed an association between the presence of deep lacunes and mixed CMB. The other collected parameters did not reveal a significant difference between the two groups. CONCLUSIONS: CAA and mixed CMB demonstrate radiological differences in the absence of macrohaemorrhages. However, more clinically available biomarkers are needed to elucidate the contribution of CAA and hypertensive angiopathy in mixed CMB patients.

Acoustically presented semantic decision-making tasks provide a robust depiction of the temporo-parietal speech areas.

Functional MRI (fMRI) is routinely used to depict language areas, for example in the preoperative diagnostic work-up of patients with a brain tumour. The objective of this study was to test whether semantic decision making can activate the temporo-parietal language areas better than phonological generation stimuli. Five fMRI language stimuli were tested in 20 healthy volunteers: (i) word generation to a given letter (WG); (ii) verb generation to a given noun (VG); (iii) generation of groups of words (GW); (iv) detection of a semantic violation in sentences (SV); and (v) detection of pseudowords (PW). The stimuli were presented both visually and acoustically. We used a block design and evaluated the data with SPM5 with predefined regions of interest in the frontal and temporo-parietal language areas. A lateralisation index (LI) was also calculated. We found that WG and VG achieved the best results in frontal language areas; VG, SV and PW presented acoustically achieved the best results in the temporo-parietal language areas; and that LI was most reliably calculated in the frontal language areas. An acoustically presented semantic decision making stimulus should be implemented in the preoperative diagnostic work-up to robustly depict the temporo-parietal language areas. The stimulus is easy to understand and perform, and it achieves robust results.