Role of diffusion tensor imaging in the evaluation of white matter integrity in idiopathic intracranial hypertension.

OBJECTIVES: To determine whether idiopathic intracranial hypertension (IIH) may affect white matter integrity and optic pathways by using diffusion tensor imaging (DTI) and to correlate the DTI metrics with intracranial pressure (ICP). METHODS: This study is a retrospective case-control study. A total of 42 patients who underwent lumbar puncture and those with elevated ICP, meeting the diagnostic criteria for IIH, were included in the study. All patients had supportive magnetic resonance imaging findings for the diagnosis of IIH. The headache control group comprised 36 patients who presented to the Neurology Department with infrequent episodic tension-type headache, had a normal neurologic examination, and had clinical and radiological findings suggestive of normal ICP. For each patient with IIH, clinical findings and ophthalmological measurements were recorded. The apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values were calculated using a region of interest-based method in different white matter tracts and optic pathways and compared. RESULTS: A total of 42 patients diagnosed with IIH (three males, 39 females), with a mean (standard deviation [SD] age of 38.1 (8.9) years), and 36 headache controls (10 males, 26 females, mean [SD] age; 38.1 [9.4] years) were included in the study. The mean (SD) body mass index (BMI) of the patients with IIH was 25.2 (1.9) kg/m2, and the mean (SD) BMI of the headache controls was 23.3 (1.5) kg/m2 (p < 0.001). Decreased FA values and increased RD values in the cingulum were detected in patients with IIH compared to the headache controls (p = 0.003, Cohen's d = 0.681; p = 0.002 Cohen's d = -0.710). Decreased AD values in the left and right superior cerebellar peduncle and increased ADC values in the middle cerebellar peduncle were detected in patients with IIH compared to the headache controls (p < 0.001, Cohen's d = 0.961; p = 0.009, Cohen's d = 0.607; p = 0.015, Cohen's d = -0.564). Increased ADC and RD values and decreased FA values in optic nerve were detected in patients with IIH (p = 0.010, Cohen's d = -0.603; p = 0.004, Cohen's d = -0.676; p = 0.015 Cohen's d = 0.568). A positive correlation was found between the cerebrospinal fluid pressure and ADC values of the left and right superior and left inferior longitudinal fasciculus, genu of the corpus callosum, and right optic radiation (r = 0.43, p = 0.005; r = 0.31, p = 0.044; r = 0.39, p = 0.010; r = 0.35, p = 0.024; r = 0,41, p = 0.007). There was a positive correlation between the retinal nerve fiber layer thickness and the ADC values of the optic nerve (r = 0.32, p = 0.039). CONCLUSIONS: Intracranial hypertension can be associated with deteriorated DTI values, which might be interpreted as a sign of impaired white matter microstructural integrity in many brain regions beyond the periventricular white matter. Pressure-induced edema and axonal degeneration may be the potential underlying mechanisms of this microstructural damage.

Effect of surgical mask and N95 respirator mask use on cerebrovascular reactivity.

Background and purpose:

Face masks are crucial parts of personal protective equipment (PPE) to reduce the risk of respiratory infections. The COVID-19 outbreak has increased healthcare workers’ use of face masks. This study aimed to evaluate changes in cerebrovascular response among healthcare workers using surgical and N95 respirator masks. 

90 healthcare workers: 30 wearing surgical masks, 30 wearing N95 respirators, and 30 without masks were included. After two-hour of face mask use, the baseline mean flow velocity (MFV) and the mean breath-holding index (BHI) of the bilateral middle cerebral arteries (MCAs) were evaluated with transcranial Doppler ultrasound. The presence of de-novo headache was recorded. BHI values ​​below 0.69 were evaluated as a sign of impaired cerebrovascular reactivity (CVR). 

The rate of de-novo headache was significantly higher in the N95 respirator mask group (p = 0.004). Compared to the control and surgical mask groups, the N95 respirator mask group had significantly lower values of the baseline MFV of the right MCA (p = 0.003 and p = 0.021, respectively) and mean BHI (p = 0.003 and p = 0.012, respectively). Still, only one N95 respirator mask user had a mean BHI value below 0.69.

Surgical masks did not signi­fi­cantly affect cerebral hemodynamics. Although N95 respirator mask use significantly decreased BHI values, the CVR is still within normal limits, and the development of de-novo headache is not directly associated with low CVR. 

Inflammatory biomarkers are correlated with thrombus burden in cerebral venous sinus thrombosis.

BACKGROUND: Increasing evidence suggests that inflammatory biomarkers play a significant role in cerebral venous sinus thrombosis (CVST). The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) are related to thrombotic conditions and indicators of systemic inflammation. OBJECTIVE: To analyze the correlation between inflammatory biomarkers and the extent of thrombus, determined by the CVST-Score. METHODS: A total of 40 patients with CVST (24 female subjects; 60%) and 40 age- and sex-matched healthy controls were retrospectively evaluated. Inflammatory biomarkers, including C-reactive protein (CRP), PLR, NLR, MLR, and the CVST-Score, were recorded to assess the relationship between biomarkers and thrombus burden. The patients were grouped according to symptom duration (group 1: 0-3 days; group 2: 4-7 days; and group 3: 8-30 days) to compare biomarker levels. RESULTS: The CRP, NLR, and PLR were significantly higher in the CVST group (p < 0.001; p = 0.003; p = 0.014 respectively). The NLR and PLR presented a significant positive correlation with the CVST-Score (p = 0.003, r = 0.464; p = 0.040, r = 0.326 respectively). The NLR was significantly higher in group 1 compared with groups 2 and 3 (p = 0.016 and p = 0.014 respectively). In group 1, there was a stronger positive correlation between the CVST-Score and the NLR (p = 0.026, r = 0.591) and the PLR (p = 0.012, r = 0.648). The multiple linear regression analysis revealed that the NLR is a key factor in predicting the CVST-Score (p = 0.019). CONCLUSION: The NLR and PLR are associated with thrombus burden in CVST, especially in patients admitted to the hospital in the early stages. The NLR is an independent factor to predict the thrombus burden in CVST.

ANTECEDENTES: Há evidências crescentes de que biomarcadores inflamatórios desempenham um papel importante na trombose venosa cerebral (TVC). A razão neutrófilo-linfócito (NLR), a razão plaqueta-linfócito (PLR) e a razão monócito-linfócito (MLR) estão relacionadas a condições trombóticas e são indicadores de inflamação sistêmica. OBJETIVO: Analisar a correlação entre NLR, PLR, MLR e a extensão do trombo, determinada pelo escore de TVC. MéTODOS: Avaliamos retrospectivamente 40 pacientes com TVC (24 mulheres; 60%) e 40 controles pareados por idade e sexo. Biomarcadores inflamatórios, incluindo proteína C reativa (PCR), PLR, NLR, MLR e escore de TVC, foram registrados para avaliar a relação entre biomarcadores e carga trombótica. Os pacientes foram agrupados de acordo com a duração dos sintomas (grupo 1: 0­3 dias; grupo 2: 4­7 dias; e grupo 3: 8­30 dias) para a comparação dos níveis de biomarcadores. RESULTADOS: A PCR, a NLR e a PLR foram significativamente maiores no grupo com TVC (p < 0,001; p = 0,003; e p = 0,014, respectivamente). A NLR e a PLR apresentaram correlação positiva significativa com o escore de TVC (p = 0,003, r = 0,464; e p = 0,040, r = 0,326, respectivamente). A NLR foi significativamente maior no grupo 1 em comparação aos grupos 2 e 3 (p = 0,016 e p = 0,014, respectivamente). No grupo 1, houve correlação mais forte entre o escore de TVC e a NLR (p = 0,026, r = 0,591) e a PLR (p = 0,012, r = 0,648). A análise de regressão linear múltipla identificou a NLR como fator-chave na predição do escore de TVC (p = 0,019). CONCLUSãO: A NLR e a PLR estão associadas à carga trombótica na TVC, especialmente em pacientes admitidos precocemente, e a RNL é um fator independente na previsão da carga trombótica.

Evaluation of Substantia Nigra morphology in Parkinson's Disease.

In the elderly population, Parkinson's Disease (PD) is the second most common neurodegenerative disorder and is associated with morphological changes in the basal ganglia, especially the substantia nigra (SN). This study aimed to evaluate the volume and signal intensity (SI) of SN using Magnetic Resonance Imaging (MRI) to detect structural changes and investigate the relationship between the onset side and disease severity of PD. Clinical features and imaging data of 58 patients with PD were retrospectively analyzed from their medical records. Axial T2-weighted fluid-attenuated inversion recovery (FLAIR) sequences of 3 Tesla (T) MRIs were used for the measurements. The right and left SN volumes and SI measurements were calculated in duplicate by 2 blinded and qualified neuroradiologists. The side of disease onset, disease duration, levodopa equivalent daily dose, Movement Disorder Society-sponsored Unified Parkinson Disease Rating Scale (MDS-UPDRS III) motor score, and modified Hoehn and Yahr (H&Y) scale scores were recorded and compared with SN volume and SI measurements. No statistically significant difference was found between the disease onset side and contralateral SN volume or SI measurements (P > .05). Despite high inter- and intra-rater reliability rates, there was no significant difference in the volume and SI of the contralateral SN according to H&Y stages (P > .05). Furthermore, SN volume and SI measurements were not significantly correlated with disease duration and MDS-UPDRS III motor score (P > .05). SN volume and SI values measured using axial FLAIR 3T MRI are not correlated with the side of onset or disease severity in PD. New imaging methods are required to detect preclinical or early-stage PD.

Evaluation of Cerebral Vasomotor Reactivity by Transcranial Doppler Ultrasound in Patients with Diabetic Retinopathy.

The aim of this study was to assess the correlation between cerebral vasomotor reactivity (CVR) and the grade of diabetic retinopathy. A total of 43 diabetic patients with matched severity of diabetic retinopathy between their right and left eyes were included in this study. Diabetic retinopathy was graded in three groups. Right and left middle cerebral artery CVR was assessed by the breath-holding index (BHI) using transcranial Doppler ultrasound (TCD). The mean age of the patients was 56.51 ± 9.34 years with a mean duration of having diabetes mellitus of 14.49 ± 8.06 years. Diabetic retinopathy was graded as mild, moderately severe, and severe in 27.9%, 34.9%, and 37.2% of the patients, respectively. The grade of diabetic retinopathy was associated with the HbA1c level (p < .049), microalbuminuria (p < .024), and BHI (p = .001). In patients with severe diabetic retinopathy, the right-sided BHI was significantly lower as compared to those with mild or moderately severe retinopathy (p = .001 and p = .008, respectively). The left-sided BHI value in patients with severe diabetic retinopathy was significantly lower as compared to those with mild or moderately severe retinopathy (p = .001 and p = .012, respectively). In subjects with moderately severe diabetic retinopathy, both-sided BHI was significantly reduced compared to those with mild retinopathy (p = .001). Our results indicate that the grade of diabetic retinopathy was associated with impaired CVR.