Twenty-four hour blood pressure variability and the prevalence and the progression of cerebral white matter hyperintensities

Vagus nerve size determined via ultrasonography is associated with white matter lesions in patients with vascular risk factors

PURPOSE

The cross-sectional area (CSA) of the cervical vagus nerve (VN), as assessed through ultrasonography, might be linked to autonomic nervous system dysfunction. Hypertension is the primary factor associated with cerebral white matter lesions (WMLs), but there is also evidence of a connection with autonomic nervous system dysfunction. However, the associations between WMLs and VN size are unclear. Our objective was to investigate the associations between WMLs and VN size in patients with vascular risk factors.

METHODS

The CSA of the VN was evaluated using carotid ultrasonography in patients with a history of stroke (acute or chronic) and comorbidities (n = 196, 70.2 ± 12.7 years). Common carotid artery (CCA) intima-media thickness and interadventitial diameter (IAD) were also measured. The severity of the WMLs was assessed by the Fazekas classification and Scheltens' scale.

RESULTS

The CSA of the right VN (2.08 ± 0.65 mm2) was significantly greater than that of the CSA of the left VN (1.56 ± 0.44 mm2) (P < 0.001). Multiple linear regression analyses revealed that older age, hypertension, increased right CCA IAD, and decreased CSA of the right VN (standardized partial regression coefficient [β] - 0.226; P < 0.001) were independently associated with the severity of WMLs (Scheltens' scale). A decreased CSA of the left VN was also associated with the severity of WMLs (β = - 0.239; P < 0.001).

CONCLUSION

VN size determined via ultrasonography was associated with the severity of WMLs. While these findings do not establish a causal relationship, they suggest that autonomic nervous system dysfunction is involved in the progression of WMLs.

Impact of blood pressure variability and cerebral small vessel disease: A systematic review and meta-analysis

Importance

Abnormal blood pressure pattern is an independent risk factor for vascular events. Blood pressure variability can predict cardiovascular and cerebrovascular disease outcomes and is closely associated with the risk of cognitive impairment. However, the relationship between blood pressure variability and cerebral small vessel disease neuroimaging markers remains unclear. This study aimed to evaluate the relationship between blood pressure variability and cerebral small vessel disease neuroimaging markers.

Data sources

We searched multiple databases, including Embase, Web of Science, PubMed, Cochrane Library, UpToDate, and World of Science, from their inception until November 27, 2023.Main Outcomes and Measures: A meta-analysis of 19 observational studies involving 14519 participants was performed. Findings: ①Systolic blood pressure variability was correlated with the cerebral small vessel disease total burden, white matter hyperintensities and lacunar infarction; ② Diastolic blood pressure variability was correlated with the cerebral small vessel disease total burden, white matter hyperintensities and cerebral microbleeds; ③ Non-dipping patterns were correlated with white matter hyperintensities and lacunar infarction. ④ Reverse-dipping patterns were significantly correlated with white matter hyperintensities and cerebral microbleeds.

Conclusions

and Relevance: Blood pressure variability correlates with neuroimaging markers of cerebral small vessel disease and its burden. Hence, early monitoring and intervention of blood pressure variability may be essential for the early diagnosis, prevention and treatment of cerebral small vessel disease.

Leukoaraiosis: Epidemiology, Imaging, Risk Factors, and Management of Age-Related Cerebral White Matter Hyperintensities

Leukoaraiosis (LA) manifests as cerebral white matter hyperintensities on T2-weighted magnetic resonance imaging scans and corresponds to white matter lesions or abnormalities in brain tissue. Clinically, it is generally detected in the early 40s and is highly prevalent globally in individuals aged >60 years. From the imaging perspective, LA can present as several heterogeneous forms, including punctate and patchy lesions in deep or subcortical white matter; lesions with periventricular caps, a pencil-thin lining, and smooth halo; as well as irregular lesions, which are not always benign. Given its potential of having deleterious effects on normal brain function and the resulting increase in public health burden, considerable effort has been focused on investigating the associations between various risk factors and LA risk, and developing its associated clinical interventions. However, study results have been inconsistent, most likely due to potential differences in study designs, neuroimaging methods, and sample sizes as well as the inherent neuroimaging heterogeneity and multi-factorial nature of LA. In this article, we provided an overview of LA and summarized the current knowledge regarding its epidemiology, neuroimaging classification, pathological characteristics, risk factors, and potential intervention strategies.

Assessments of variability in cortical and subcortical measurements and within-network connectivity of the brain using test-retest data

The evaluation and diagnosis of structural changes in brain caused by disease or treatment over time has become one of the important applications of medical imaging methods, in particular MRI, and it is growing. It is critical to evaluate the reliability of the changes in measurements observed in an individual patient for any clinical decision-making. In this paper, we calculated the repeatability coefficient (RC) as a measure of uncertainty for MRI measurements of subcortical volumes and cortical thickness, and within-network connectivity using test-retest data of 20 healthy subjects. We also evaluated changes in 13 patients who received 20 sessions of transcranial magnetic stimulation as a treatment. The most reliable measure seems to be in the thickness of the left occipital with RC% of 3.5 and the least reliable measure is the brain connectivity within visual network using Yeo's atlas with RC% of 29.4. The most sensitive measure to the percentage of true changes in treated patients is the connectivity within subcortical network of AAL with 76.9%.Clinical Relevance- The results of this study can be useful for evaluating changes in the gray matter structures or functional connectivity of the brain due to a neurological disease such as Alzheimer's or Parkinson's. Also, the obtained results can be used to evaluate the changes caused by any intervention or treatment that may have any positive or negative effect on the brain.