Incidental periventricular white matter hyperintensities revisited: what detailed morphologic image analyses can tell us

Incompleteness of the Circle of Willis and progression of white matter hyperintensities of presumed vascular origin. A longitudinal prospective study in community-dwelling older adults

BACKGROUND

Evidence on the association between anatomical variants of the circle of Willis (CoW) and severity of white matter hyperintensities (WMH) of presumed vascular origin is inconclusive, and no study has evaluated the role of incompleteness of CoW on WMH progression in the follow-up. This study aims to assess the impact of incomplete configurations of the CoW on WMH progression in community-dwelling older adults.

METHODS

Following a prospective longitudinal study design, individuals aged ≥60 years enrolled in the Atahualpa Project Cohort from 2012 to 2019 were invited to receive baseline brain MRI and MRA of intracranial vessels, and those who also had brain MRIs at the end of the study (May 2021) were included in the analysis. Poisson regression models, adjusted for demographics and cardiovascular risk factors, were fitted to assess the incidence rate ratio (IRR) of WMH progression according to incompleteness of CoW.

RESULTS

This study included 254 individuals (mean age: 65.4±5.9 years; 55% women). An incomplete CoW was detected in 99 (39%) subjects. Follow-up MRIs showed WMH progression in 103 (41%) individuals after a median follow-up of 6.5±1.4 years. WMH progression was observed in 58/155 subjects with complete and in 45/99 with incomplete CoW (37% versus 45%; p=0.203). There was no association between incomplete CoW and WMH progression in a multivariate Poisson regression model (IRR: 1.21; 95% C.I.: 0.81 - 1.82).

CONCLUSIONS

Study results show that incompleteness of CoW is not involved in WMH progression.

The Clinical Value of Periventricular White Matter Hyperintensity on MRI in Sudden Sensorineural Hearing Loss

OBJECTIVES

To assess the clinical value of periventricular white matter hyperintensity (PWMH) found on brain magnetic resonance imaging (MRI) in patients with sudden sensorineural hearing loss (SSNHL).

METHODS

In this prospective study, 115 patients who were diagnosed with SSNHL aged between 55 and 75 years were analyzed. All subjects underwent brain MRI and were divided into a PWMH and control groups, depending on the presence of PWMH on MRI. PWMH was subdivided into 3 groups according to severity. Pure-tone average results and hearing gain were compared between the 2 groups before treatment and 2 months after treatment. Hearing improvement was assessed using Sigel's criteria.

RESULTS

A total of 106 patients (43 in the PWMH group and 63 in the control group) finally completed the 2-month follow-up. Average hearing gain in the PWMH group was significantly higher than in the control group (34.8 ± 20.3 and 25.9 ± 20.3, respectively, P = .029). PWMH score 1 showed significantly better hearing levels and hearing gain compared to PWMH score 3 and the control group. Multivariate analysis revealed that younger age, better initial hearing level, and the presence of PVWM score 1 were associated with good recovery.

CONCLUSIONS

The presence of PWMH score 1 on brain MRI in patients with SSNHL was associated with better treatment response and was a good prognostic factor in a multivariate analysis while the hearing recovery in more severe PWMH (scores 2, 3) was not different from the control group.

Association between white matter lesions and the cerebral glucose metabolism in patients with cognitive impairment

AIM

White matter lesions (WMLs), detected as hyperintensities on T2-weighted MRI, represent small vessel disease in the brain and are considered a potential risk factor for memory and cognitive impairment. It has not been sufficiently evident that cognitive impairment in patients with Alzheimer's disease is caused by WMLs as well as β-amyloid (Aβ) pathology. The aim of this study was to evaluate relationship between WMLs and cerebral glucose metabolism in patients with cognitive impairment after adjustment of cerebral Aβ burden.

MATERIALS AND METHODS

Eighty-three subjects with cognitive performance ranging from normal to dementia, who underwent brain MRI and ¹⁸F-florbetaben positron emission tomography (PET) and ¹⁸F-fluorodeoxyglucose PET, were included in this cross-sectional study. The Fazekas scale was used to quantify WMLs on brain T2-weighted MRI. The cerebral Aβ burden and cerebral glucose metabolism were quantitatively estimated using volume-of-interest analysis. Differences in the regional cerebral glucose metabolism were evaluated between low-WML (Fazekas scale<2) and high-WML (Fazekas scale≥2) groups. Multiple linear regression analysis adjusted for age, sex and cerebral Aβ burden was performed to evaluate the relationship between the Fazekas scale score and cerebral glucose metabolism.

RESULTS

The regional cerebral glucose metabolism for the bilateral frontal, temporal, and parietal cortices, and limbic lobes in the high-WML group were significantly lower than those in the low-WML group. There were significant negative correlations between the Fazekas scale score and regional cerebral glucose metabolism in the bilateral frontal, bilateral temporal and left parietal cortices, and bilateral limbic lobes. Multiple linear regression analysis revealed that the Fazekas scale score was an independent determinant of the glucose metabolism in the bilateral frontal and temporal cortices and limbic lobes.

CONCLUSIONS

WMLs are associated with decreased cerebral glucose metabolism. Our findings suggest that small vessel disease, as well as Aβ pathology, may contribute to cognitive impairment in patients with Alzheimer's disease.

Severity of White Matter Hyperintensities and Effects on All-Cause Mortality in the Mayo Clinic Florida Familial Cerebrovascular Diseases Registry

OBJECTIVE

To compare all-cause mortality rates across the severity range of white matter hyperintensities (WMH).

PATIENTS AND METHODS

Between October 26, 2010, and October 5, 2017, the ongoing Mayo Clinic Florida Familial Cerebrovascular Diseases Registry prospectively enrolled 1011 diverse participants with and without cerebrovascular disease. T2-weighted magnetic resonance imaging of the brain was used to evaluate WMH in 455 participants using the Fazekas scale. Fazekas deep WMH (FD) and periventricular WMH (FPV) scores (0-3 points) were assigned on the basis of WMH severity. Kaplan-Meier survival analyses, Cox proportional hazards models, and estimated hazard ratios compared survival rates across FD and FPV categories. The Fisher exact and χ² tests evaluated the relationship of categorical variables, and the Kruskal-Wallis test measured the relationship of continuous variables across FD and FPV categories. All tests were performed at a P<.05 significance level.

RESULTS

Over a median follow-up of 3.06 years (range, 0.00-6.96 years), 96 deaths occurred. Higher FD scores corresponded to a higher likelihood of mortality (P<.001). Participants with an FD score of 3 were 4.69 (95% CI, 2.60-8.46) times more likely to die compared with those with an FD score of 0. Participants with higher FPV scores had a higher likelihood of mortality (P<.001). Participants with an FPV score of 3 were 7.04 (95% CI, 3.39-14.62) times more likely to die compared with those with an FPV score of 0. Once adjusted, age and baseline functional status explained most of the survival differences among the FD scores.

CONCLUSION

Associations between all-cause mortality rates across the severity range of WMH were observed in the Registry. Further studies are warranted to understand the clinical importance of WMH in other clinical populations.

MR evaluation of encephalic leukoaraiosis in sudden sensorineural hearing loss (SSNHL) patients

Epidemiological evidence suggests a strict correlation between sudden sensorineural hearing loss (SSNHL) and cerebrovascular disorders. Leukoaraiosis represents a diffuse alteration of the periventricular and subcortical white matter. The aim of our study was to verify if the presence of white matter hyperintensity (WMH) was higher in patients affected by SSNHL compared to controls and evaluate the correlation between WMH and the cardiovascular risk factors, hearing level, and the response to therapy in SSNHL patients. The study group included 36 subjects affected by unilateral SSNHL. Thirty-six age- and sex-matched normal subjects with a negative history of SSNHL were used as controls. All patients underwent magnetic resonance imaging (MRI) (1.5 Tesla GE Signa) and the extent of leukoaraiosis was assessed with the Fazekas scale. The results of the present study demonstrate a high prevalence of WMH in SSNHL patients compared to controls confirming the hypothesis of a vascular impairment in SSNHL patients. The higher recovery rate in patients with greater periventricular white matter hyperintensity (PWMH) may suggest a vascular etiology that is still responsive to medical treatment. We aim to expand both the number of patients and the controls to avoid the limitation of the still small number to warrant solid scientific conclusions.