Detection and characterization of small infarcts in the caudate nucleus on 7 Tesla MRI: The SMART-MR study

Examining Brain Structures and Cognitive Functions in Patients with Recovered COVID-19 Infection: A Multicenter Study Using 7T MRI

Importance

Emerging evidence suggests that severe acute respiratory syndrome, COVID-19, negatively impacts brain health, with clinical magnetic resonance imaging (MRI) showing a wide range of neurologic manifestations but no consistent pattern. Compared with 3 Tesla (3T) MRI, 7 Tesla (7T) MRI can detect more subtle injuries, including hippocampal subfield volume differences and additional standard biomarkers such as white matter lesions. 7T MRI could help with the interpretation of the various persistent post-acute and distal onset sequelae of COVID-19 infection.

Objective

To investigate the differences in white matter hyperintensity (WMH), hippocampal subfields volumes, and cognition between patients hospitalized with COVID-19 and non-hospitalized participants in a multi-site/multi-national cohort.

Design

Original investigation of patients hospitalized with COVID-19 between 5/2020 and 10/2022 in 3 USA and 1 UK medical centers with follow-up at hospital discharge.

Participants

A total of 179 participants without a history of dementia completed cognitive, mood and other assessments and MRI scans.

Exposure

COVID-19 severity, as measured by hospitalization vs no hospitalization.

Main Outcomes and Measures

7T MRI scans were acquired. All WMH and hippocampal subfield volumes were corrected for intracranial volumes to account for subject variability. Cognition was assessed using a comprehensive battery of tests. Pearson correlations and unpaired t-tests were performed to assess correlations and differences between hospitalized and non-hospitalized groups.

Results

We found similar WMH volume (4112 vs 3144mm³, p=0.2131), smaller hippocampal volume (11856 vs 12227mm³, p=0.0497) and lower cognitive and memory performance, especially the MoCA score (24.9 vs 26.4 pts, p=0.0084), duration completing trail making test B (97.6 vs 79.4 seconds, p=0.0285), Craft immediate recall (12.6 vs 16.4 pts, p<0.0001), Craft delay recall (12.0 vs 15.6 pts, p=0.0001), and Benson figure copy (15.2 vs 16.1 pts, p=0.0078) in 52 patients hospitalized for COVID-19 (19[37%] female; mean[SD] age, 61.1[7.4] years) compared with 111 age-matched non-hospitalized participants (66[59%] female; mean[SD] age, 61.5[8.4] years).

Conclusions and Relevance

Our results indicate that hospitalized COVID-19 cases show lower hippocampal volume when compared to non-hospitalized participants. We also show that WMH and hippocampal volumes correlate with worse cognitive scores in hospitalized patients compared with non-hospitalized participants, potentially indicating recent lesions and atrophy.

Key Points

Question: Do white matter hyperintensity burden, hippocampal whole and subfield volumes, and cognition differ between patients hospitalized with COVID-19 versus participants without hospitalization?Findings: We found no significant difference in white matter hyperintensity volume, but hippocampal volume was reduced, and cognitive and memory performance were worse in those hospitalized for COVID-19 compared with age-matched non-hospitalized group (either mild COVID-19 or no COVID-19 reported). In the hospitalized group, increased white matter hyperintensity and reduced hippocampal volumes are significantly higher correlated with worse cognitive and memory scores.Meaning: Adults hospitalized for COVID-19 had lower hippocampal volumes and worse cognitive performance than adults with COVID-19 that did not lead to hospitalization or without reported COVID-19 infection.

Incidental discovery of chronic lacunar infarction in the head of the caudate nucleus: pathophysiological considerations and retroactive etiologic diagnosis of a depressive syndrome. Case presentation

: Introduction. Neuroimaging studies demonstrated the complex caudate nucleus' interrelationships within topographically organized cortical networks and its strategic role in emotional balance. Case presentation. The clinical case depicts a 71-year-old female patient with chronic depressive syndrome, orthostatic hypotension, hyperlipidemia, and arthritis. CT cerebral imagery incidentally revealed an old lacunar infarction in the right caudate nucleus with a diameter of about 6 mm. Written informed consent was obtained from the patient for the inclusion and use of materials related to the case, respecting the confidentiality of her identity data. The presentation of this clinical case has the approval of the ethics commission of TEHBA (no. 40205/01.09.2023). Discussion. The authors hypothesized that the old lacuna was incriminated as the organic substrate for chronic neuropsychiatric illness in an older woman with risk factors for cerebral small vessel disease. The etiopathological assumption was contextualized in a selective literature review that focused on relevant data from recent publications and emphasized the caudate`s strategic role in emotional balance and dysthymia. Unilateral or bilateral small lacunae in the caudate nuclei are associated with a high risk of developing psychiatric complications but not motor deficits after stroke.

Microinfarcts in the Deep Gray Matter on 7T MRI: Risk Factors, MRI Correlates, and Relation to Cognitive Functioning-The SMART-MR Study

BACKGROUND AND PURPOSE

The clinical relevance of cortical microinfarcts has recently been established; however, studies on microinfarcts in the deep gray matter are lacking. We examined the risk factors and MR imaging correlates of microinfarcts in the deep gray matter on 7T MR imaging and their relation to cognitive functioning.

MATERIALS AND METHODS

Within the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) study, 213 patients (mean age, 68 [SD, 8] years) had a risk-factor assessment, 7T and 1.5T brain MR imaging, and a cognitive examination. Microinfarcts on 7T MR imaging were defined as lesions of <5 mm. Regression models were used to examine the age-adjusted associations among risk factors, MR imaging markers, and microinfarcts. Cognitive function was summarized as composite and domain-specific z scores.

RESULTS

A total of 47 microinfarcts were found in 28 patients (13%), most commonly in the thalamus. Older age, history of stroke, hypertension, and intima-media thickness were associated with microinfarcts. On 1.5T MR imaging, cerebellar infarcts (relative risk = 2.75; 95% CI, 1.4-5.33) and lacunes in the white (relative risk = 3.28; 95% CI, 3.28-6.04) and deep gray matter (relative risk = 3.06; 95% CI, 1.75-5.35) were associated with microinfarcts, and on 7T MR imaging cortical microinfarcts (relative risk = 2.33; 95% CI, 1.32-4.13). Microinfarcts were also associated with poorer global cognitive functioning (mean difference in the global z score between patients with multiple microinfarcts versus none = -0.97; 95% CI, -1.66 to -0.28, P = .006) and across all cognitive domains.

CONCLUSIONS

Microinfarcts in the deep gray matter on 7T MR imaging were associated with worse cognitive functioning and risk factors and MR imaging markers of small-vessel and large-vessel disease. Our findings suggest that microinfarcts in the deep gray matter may represent a novel imaging marker of vascular brain injury.

Associations of subclinical cerebral small vessel disease and processing speed in non-demented subjects: A 7-year study

Markers of cerebral small vessel disease (CSVD) have previously been associated with age-related cognitive decline. Using longitudinal data of cognitively healthy, older adults (N = 216, mean age at baseline = 70.9 years), we investigated baseline status and change in white matter hyperintensities (WMH) (total, periventricular, deep), normal appearing white matter (NAWM), brain parenchyma volume (BPV) and processing speed over seven years as well as the impact of different covariates by applying latent growth curve (LGC) models. Generally, we revealed a complex pattern of associations between the different CSVD markers. More specifically, we observed that changes of deep WMH (dWMH), as compared to periventricular WMH (pWMH), were more strongly related to the changes of other CSVD markers and also to baseline processing speed performance. Further, the number of lacunes rather than their volume reflected the severity of CSVD. With respect to the studied covariates, we revealed that higher education had a protective effect on subsequent total WMH, pWMH, lacunar number, NAWM volume, and processing speed performance. The indication of antihypertensive drugs was associated with lower lacunar number and volume at baseline and the indication of antihypercholesterolemic drugs came along with higher processing speed performance at baseline. In summary, our results confirm previous findings, and extend them by providing information on true within-person changes, relationships between the different CSVD markers and brain-behavior associations. The moderate to strong associations between changes of the different CSVD markers indicate a common pathological relationship and, thus, support multidimensional treatment strategies.

The association between intraoperative hyperglycemia and cerebrovascular markers

BACKGROUND AND PURPOSE: Hyperglycemia can lead to an increased rate of apoptosis of microglial cells and to damaged neurons. The relation between hyperglycemia and cerebrovascular markers on MRI is unknown. Our aim was to study the association between intraoperative hyperglycemia and cerebrovascular markers. METHODS: In this further analysis of a subgroup investigation of the BIOCOG study, 65 older non-demented patients (median 72 years) were studied who underwent elective surgery of ≥ 60 minutes. Intraoperative blood glucose maximum was determined retrospectively in each patient. In these patients, preoperatively and at 3 months follow-up a MRI scan was performed and white matter hyperintensity (WMH) volume and shape, infarcts, and perfusion parameters were determined. Multivariable logistic regression analyses were performed to determine associations between preoperative cerebrovascular markers and occurrence of intraoperative hyperglycemia. Linear regression analyses were performed to assess the relation between intraoperative hyperglycemia and pre- to postoperative changes in WMH volume. Associations between intraoperative hyperglycemia and postoperative WMH volume at 3 months follow-up were also assessed by linear regression analyses. RESULTS: Eighteen patients showed intraoperative hyperglycemia (glucose maximum ≥ 150 mg/dL). A preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia [convexity: OR 33.318 (95 % CI (1.002 - 1107.950); p = 0.050]. Other preoperative cerebrovascular markers were not related to the occurrence of intraoperative hyperglycemia. Intraoperative hyperglycemia showed no relation with pre- to postoperative changes in WMH volume nor with postoperative WMH volume at 3 months follow-up. CONCLUSIONS: We found that a preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia. These findings may suggest that a similar underlying mechanism leads to a certain pattern of vascular brain abnormalities and an increased risk of hyperglycemia.

A neuroanatomical study of the feline brain using MRI and mulligan staining: functional and pathological considerations

BACKGROUND

Despite multiple studies describing accurate diagnoses using advanced neuroimaging techniques, low and mid-field magnetic resonance imaging (MRI) are still the most frequent scanners in veterinary clinics. To date, these studies in cats do not show a clear distinction of nerve centres in MRI data.

AIMS

The objective of this study is to determine the efficacy of Mulligan histological staining as a tool in facilitating the location and identification of the main structures of the feline brain in MRI. This study aims to facilitate the interpretation of MRI obtained with these types of scanners.

METHODS

A total of 10 feline brains were used. One specimen was used for MRI (T2 sequence using a 1.5T scanner). The other 9 brains were sectioned and stained with the three Mulligan staining techniques (Mulligan, Le Masurier and Robert).

RESULTS

The uptake of stain by the grey matter in these sections allowed the determination of the location and the limits of these nervous structures within the brain. The histological location of these structures was correlated with the MRI scans, leading to the successful identification of many small, indistinct nuclei.

CONCLUSION

Mulligan staining is proposed as a tool that facilitates the location of nerve structures in comparison with data from the most frequently-used MRI scanners in veterinary clinics.

Visualizing the Human Subcortex Using Ultra-high Field Magnetic Resonance Imaging

With the recent increased availability of ultra-high field (UHF) magnetic resonance imaging (MRI), substantial progress has been made in visualizing the human brain, which can now be done in extraordinary detail. This review provides an extensive overview of the use of UHF MRI in visualizing the human subcortex for both healthy and patient populations. The high inter-subject variability in size and location of subcortical structures limits the usability of atlases in the midbrain. Fortunately, the combined results of this review indicate that a large number of subcortical areas can be visualized in individual space using UHF MRI. Current limitations and potential solutions of UHF MRI for visualizing the subcortex are also discussed.