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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/m 2 , and the mean (SD) BMI of the headache controls was 23.3 (1.5) kg/m 2 (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., (© 2024 American Headache Society.)

Background: To investigate whether there is a difference in mean diffusivity (MD) and fractional anisotropy (FA) values in the auditory pathways of neurofibromatosis type 1 patients with and without focal areas of abnormal signal intensity (FASI) compared to healthy controls by using diffusion tensor imaging (DTI). Methods: Patients were classified as group 1 with focal areas of abnormal signal intensity in the brainstem, group 2 without focal areas of abnormal signal intensity, and healthy control group 3 according to the MRI findings. Mean diffusivity and fractional anisotropy values of lateral lemniscus, inferior colliculus, corpus geniculatum mediale, Heschl gyrus, and brainstem were compared between groups. The correlation between mean diffusivity and fractional anisotropy values of auditory pathways and age was investigated. Results: There was a significant difference between group 1 and group 2 in terms of mean diffusivity and fractional anisotropy values at lateral lemniscus, inferior colliculus, corpus geniculatum mediale, and Heschl gyrus. Increased mean diffusivity and decreased fractional anisotropy values at brainstem were found in group 1. There was a significant difference between group 1 and group 3 in terms of mean diffusivity values at all auditory pathways. Fractional anisotropy values obtained from lateral lemniscus, inferior colliculus, and Heschl gyrus decreased in group 1 compared with group 3. There was a negative correlation between mean diffusivity values and positive correlation between fractional anisotropy values at lateral lemniscus, inferior colliculus, Heschl gyrus, and age. Conclusions: Our diffusion tensor imaging findings show that the neuronal integrity of the auditory pathways is affected in neurofibromatosis type 1 patients with brainstem focal areas of abnormal signal intensity. We think that the disappearance of brainstem focal areas of abnormal signal intensity associated with myelin repair and the regression of diffusion tensor imaging changes in the auditory pathways occur simultaneously with advancing age in patients with neurofibromatosis type 1., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objectives: The purpose of this study to determinate whether there is a relationship between the nutritional status and white matter integrity in older patients by using Diffusion Tensor Imaging (DTI)., Methods: The patients were evaluated by Mini-Nutritional Assessment Scale. The patients are categorized in the groups of well-nourished, risk of malnutrition, or malnourished, depending on the overall score> 23.5, 17-23.5, or 17; respectively. All patients had brain MRI and DTI. The mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) values were calculated by ROI-based method in white matter tracts., Results: Total of the 224 patients; 86 patients had normal nutrition status (group 1), 107 patients were diagnosed with malnutrition risk (group 2) and 31 patients were diagnosed with malnutrition (group 3). Significantly decreased FA values of genu of corpus callosum, forceps minor and significantly increased MD values of middle cerebellar peduncle, and superior frontooccipital fasciculus were detected in group 2 in comparison to group 1 (p < 0.05). After adjusting for the folate and age, MD and RD values of cingulum remained significantly higher and the AD values of superior cerebellar peduncle remained significantly lower in group 3 (p < 0.05)., Conclusions: Malnutrition was associated with deteriorated DTI values, especially in cingulum and superior cerebellar peduncle. Assessing the nutritional status of older individuals is crucial to avoid its negative impact on brain., Advances in Knowledge: Early diagnosis of malnutrition-related impaired WM integrity is important for prevention and intervention, and DTI is a useful non-invasive technique to be used for this purpose., Competing Interests: Conflicts of interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Purpose: To investigate whether the diffusion tensor imaging (DTI) parameters alterations in the in hypoxia-related neuroanatomical localizations in patients after COVID-19. Additionally, the relationship between DTI findings and the clinical severity of the disease is evaluated., Methods: The patients with COVID-19 were classified into group 1 (total patients, n = 74), group 2 (outpatient, n = 46), and group 3 (inpatient, n = 28) and control (n = 52). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from the bulbus, pons, thalamus, caudate nucleus, globus pallidum, putamen, and hippocampus. DTI parameters were compared between groups. Oxygen saturation, D dimer and lactate dehydrogenase (LDH) values associated with hypoxia were analyzed in inpatient group. Laboratory findings were correlated with ADC and FA values., Results: Increased ADC values in the thalamus, bulbus and pons were found in group 1 compared to control. Increased FA values in the thalamus, bulbus, globus pallidum and putamen were detected in group 1 compared to control. The FA and ADC values obtained from putamen were higher in group 3 compared to group 2. There was a negative correlation between basal ganglia and hippocampus FA values and plasma LDH values. The ADC values obtained from caudate nucleus were positively correlated with plasma D Dimer values., Conclusion: ADC and FA changes may reveal hypoxia-related microstructural damage after COVID-19 infection. We speculated that the brainstem and basal ganglia can affected during the subacute period., (© 2023 Wiley Periodicals LLC.)

Purpose: The aim of this study was to investigate correlations between clinical symptoms, cerebrospinal fluid flow metrics, hydrocephalus index, small-vessel disease, and white matter (WM) changes in normal pressure hydrocephalus (NPH)., Methods: Aquaductal stroke volumes (ASVs), Z Evans index, Fazekas grading (FG), and diffusion tensor imaging measurements from WM bundles of 37 patients with NPH were retrospectively evaluated. Mann-Whitney U test between clinical symptoms and other variables and Spearman ρ correlations for relationships between variables and Kruskal-Wallis to correlate FG with nonclinical variables were used., Results: Patients with NPH had increased ASV (median 53 μL). No correlation was found between Z Evans index and ASV. Three groups of patients with dementia or ataxia or incontinence had increased ASV values than their counterparts without symptoms (55 vs 48.5 μL, 75 vs 47 μL, 64 vs 49.5 μL, respectively). Patients having 2 common symptoms of dementia and ataxia and patients having all 3 symptoms of dementia, ataxia, and incontinence were compared with ASV values of 63.5 versus 78 μL, respectively. Patients with FG 1 had median ASV values of 45 μL; FG 2, 82.5 μL; and FG 3, 59 μL. Patients with dementia had significantly higher apparent diffusion coefficient (ADC) values of corona radiata (CR) on both sides. There were no significant WM changes in patients with ataxia and incontinence. The Z Evans index was positively correlated with ADC values of CR on both sides and genu of corpus callosum. Fazekas grading was found positively correlated with ADC and negatively correlated with FA values of CR., Conclusions: Patients with NPH, regardless of stages of the diseases, have increased ASV values and could benefit from shunting. Decreasing ASV values of patients with FG 3 comparing with those with FG 2 support the hypothesis of decreasing compliance of brain with aging and increasing severity of small-vessel disease.

Purpose: We aimed to evaluate the change in bilateral auditory pathways using diffusion tensor imaging (DTI) after gamma knife radiosurgery (GKR) and to determine the relationship between the radiosurgical treatment variables and DTI findings., Methods: In this study 13 patients with unilateral acoustic neuroma and 11 controls underwent routine magnetic resonance imaging (MRI) and DTI. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured from the bilateral auditory pathways in all individuals before and after GKR., Results: Before GKR, subjects' ADC values obtained from the contralateral side were higher at the lateral lemniscus, medial geniculate body and Heschl's gyrus compared to those of the controls. No statistical differences were found in ADC and FA obtained at bilateral auditory pathways before and after GKR. The ADCs measured at the lateral lemniscus were positively correlated with the maximum radiation dose delivered to the brainstem (BS) and the brainstem volume receiving a radiation dose of 10 Gy (BS V10). A negative correlation was found between the FA measured from the inferior colliculus and the maximum radiation dose to the cochlea. The ADCs at the inferior colliculus were positively correlated with the mean radiation dose to the cochlea., Conclusion: There were no significant differences in the degree of involvement before and after GKR, revealing that GKR did not significantly affect the auditory pathways at 4 months. The major factors that may lead to microstructural injury to auditory pathways at the brainstem level are associated with maximum brainstem radiation dose, BS V10, and cochlear dose. These findings may suggest that more attention should be paid to anatomical structures including the cochlea and brainstem during treatment planning of GKR.

Objective: The aim of our study is to evaluate whether there were any diffusion tensor imaging (DTI) parameter changes in the visual pathways in children with neuronal ceroid lipofuscinosis (NCL) for the early detection of visual pathway damage. Methods: Eight patients diagnosed with NCL and 11 controls were included. The fractional anisotropy (FA), apparent diffusion coefficient (ADC), and radial diffusivity (RD) were measured from the visual pathways on DTI. Values of DTI were compared between healthy volunteers and NCL subjects. Results: There were statistically significant differences in FA, ADC, and RD values obtained from visual pathways in children with NCL. The FA values measured from the occipital lobe at the level of the calcarine cortex were significantly lower in these subjects. The ADC values obtained from the optic chiasm were significantly increased in children with NCL. Also, we detected significantly increased ADC and RD values obtained from the lateral geniculate nucleus and subcortical white matter of the calcarine cortex in NCL subjects. Conclusion: Optic pathway damage is a core feature in NCL children and the early detection of visual damage is crucial. Therefore, determining the microstructural diffusion changes by using DTI in visual pathways of NCL subjects may provide useful information to understand the underlying pathophysiology of the visual deterioration in NCL and other neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Objective: The aim of our study was to investigate whether there are diffusion tensor imaging (DTI) changes in the white matter pathways and to determine its relationship with tuber load and corpus callosum volume (CCV). Methods: Our study included 24 children with tuberous sclerosis complex (TSC) (group 1) and 30 healthy controls (group 2). Total tuber load and CCV were calculated. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the 15 different white matter tracts were measured. The correlation between the total tuber volume, CCV, and white matter changes was investigated. Results: The ADC values of forceps major and corticospinal tract (CST) were increased in group 1 compared to group 2. The FA values of corpus callosum splenium (CCS) were decreased in group 1 compared to group 2. There was a positive correlation between ADC values at corona radiata (CR), corpus callosum genu (CCG), forceps minor, forceps major, and tuber volume. There was a negative correlation between FA values at the anterior limb internal capsule (ALIC) and tuber volume. There was a negative correlation between the total tuber volume and CCV. There was a negative correlation between ADC values at CCG, ALIC, middle cerebellar pedicle (MCP), and CCV. There was a positive correlation between FA values at CCG and CCV. Conclusion: We hypothesized that the white matter microstructure was prominently affected in TSC subjects, this might resulted in decrease in CCV, and it is correlated with the tuber load. Furthermore, more comprehensive studies are needed to determine the relationship between the neurocognitive dysfunction, DTI metrics, and tuber and CCV. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the difference in FA (Fractional anisotropy), ADC (Apparent diffusion coefficient), RD (Radial diffusivity) and AD (axial diffusivity) values of white matter (WM) tracts in morbidly obese subjects before and after bariatric surgery (BS). Materials and Methods: A group of thirty‐nine morbidly obese subjects are evaluated before and 4–6 months after BS. ADC, FA, RD and AD values of 17 distinct neuroanatomic localizations are measured and DTI parameters are analyzed. Results: Following the BS, the patients' mean BMI decreased from 47.665.21 to 31.723.97. A significant difference is displayed between the pre‐surgery and post‐surgery FA values of SLF, SFOF, ALIC, fornix, ILF, CST, MCP (p = 0.010, p < 0.001, p = 0.048, p = 0.014, p = 0.012, p = 0.012, p = 0.040 respectively). Following BS, decrease in FA values in the mentioned areas are detected. ADC values obtained from MCP are significantly lower in the post‐BS period compared to pre‐BS period (p = 0.018). There was a statistically significant difference between the pre‐surgery and post‐surgery AD values of SLF, SFOF, ILF, ALIC, EC, CST, and MCP (p = 0.001, p = 0.022, p = 0.001, p = 0.011, p = 0.001, p = 0.000, p = 0.000, respectively). Following the BS, AD values of the SLF, SFOF, ILF, ALIC, EC, CST, and MCP are decreased. RD values measured from GCC are significantly lower in the post‐BS period compared to pre‐BS period (p = 0.008). Conclusion: Our study supported the hypothesis of the BS‐induced reversibility of the low‐grade inflammation in WM tracts in the morbidly obese group following BS. Our DTI results may represent the subacute period findings of the reversal of low‐grade inflammation after BS. [ABSTRACT FROM AUTHOR]

To determine whether there is a difference in the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of the anterior thalamic radiation (ATR), which are involved in the inhibitory control mechanism, in Neurofibromatosis type-1 (NF1) patients with or without Neurofibromatosis bright objects (NBOs), in comparison to the healthy control group. Thirty children diagnosed with NF1 and 17 age-matched children were included in the study. 30 children with NF1 had a mean age of 10.47±5.43, compared to 11.35±5.43 of the control group. NF1 patients were divided into two groups as those with and without NBOs. The comparison was made by measuring ADC and FA values of ATR in patients with NF1 and a healthy control group. There was a significant difference in terms of ADC and FA values of ATR between the patients with NF1 and the control group. While a significant decrease was seen in FA values of ATR, ADC values were increased. There was a significant difference in ATR ADC and FA values between NF1 patients with and without NBOs and the healthy control group. On the other hand, no major difference was displayed between NF1 patients with NBOs and without NBOs in terms of ATR ADC and FA values. The results of increased ADC and decreased FA values may denote the demyelination process in ATR. We speculate that the onset of microstructural damage in the ATR may result in executive function impairment, particularly in the inhibitory control mechanism. [ABSTRACT FROM AUTHOR]