scholarly journals Diffusion tensor imaging for the study of early renal dysfunction in patients affected by bardet-biedl syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pasquale Borrelli ◽  
Miriam Zacchia ◽  
Carlo Cavaliere ◽  
Luca Basso ◽  
Marco Salvatore ◽  
...  
Keyword(s):  
Renal Function ◽  
Diffusion Tensor Imaging ◽  
Renal Dysfunction ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Bardet Biedl Syndrome ◽  
Axial Diffusivity ◽  
Microstructural Alterations ◽  
Corticomedullary Differentiation ◽  
Estimated Glomerular Filtration Rates

AbstractKidney structural abnormalities are common features of Bardet-Biedl syndrome (BBS) patients that lead to a progressive decline in renal function. Magnetic resonance diffusion tensor imaging (DTI) provides useful information on renal microstructures but it has not been applied to these patients. This study investigated using DTI to detect renal abnormalities in BBS patients with no overt renal dysfunction. Ten BBS subjects with estimated glomerular filtration rates over 60 ml/min/1.73m2 and 14 individuals matched for age, gender, body mass index and renal function were subjected to high-field DTI. Fractional anisotropy (FA), and mean, radial and axial diffusivity were evaluated from renal cortex and medulla. Moreover, the corticomedullary differentiation of each DTI parameter was compared between groups. Only cortical FA statistically differed between BBS patients and controls (p = 0.033), but all the medullary DTI parameters discriminated between the two groups with lower FA (p < 0.001) and axial diffusivity (p = 0.021) and higher mean diffusivity (p = 0.043) and radial diffusivity (p < 0.001) in BBS patients compared with controls. Corticomedullary differentiation values were significantly reduced in BBS patients. Thus, DTI is a valuable tool for investigating microstructural alterations in renal disorders when kidney functionality is preserved.

scholarly journals Alternative Microstructural Measures to Complement Diffusion Tensor Imaging in Migraine Studies with Standard MRI Acquisition

2020 ◽  
Vol 10 (10) ◽  
pp. 711
Author(s):  
Álvaro Planchuelo-Gómez ◽  
David García-Azorín ◽  
Ángel L. Guerrero ◽  
Rodrigo de Luis-García ◽  
Margarita Rodríguez ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Chronic Migraine ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Episodic Migraine ◽  
Healthy Controls ◽  
Axial Diffusivity ◽  
Average Diffusion ◽  
Cerebellar Peduncle

The white matter state in migraine has been investigated using diffusion tensor imaging (DTI) measures, but results using this technique are conflicting. To overcome DTI measures, we employed ensemble average diffusion propagator measures obtained with apparent measures using reduced acquisitions (AMURA). The AMURA measures were return-to-axis (RTAP), return-to-origin (RTOP) and return-to-plane probabilities (RTPP). Tract-based spatial statistics was used to compare fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity from DTI, and RTAP, RTOP and RTPP, between healthy controls, episodic migraine and chronic migraine patients. Fifty healthy controls, 54 patients with episodic migraine and 56 with chronic migraine were assessed. Significant differences were found between both types of migraine, with lower axial diffusivity values in 38 white matter regions and higher RTOP values in the middle cerebellar peduncle in patients with a chronic migraine (p < 0.05 family-wise error corrected). Significantly lower RTPP values were found in episodic migraine patients compared to healthy controls in 24 white matter regions (p < 0.05 family-wise error corrected), finding no significant differences using DTI measures. The white matter microstructure is altered in a migraine, and in chronic compared to episodic migraine. AMURA can provide additional results with respect to DTI to uncover white matter alterations in migraine.

scholarly journals Global diffusion tensor imaging derived metrics differentiate glioblastoma multiforme vs. normal brains by using discriminant analysis: introduction of a novel whole-brain approach

2014 ◽  
Vol 48 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Ernesto Roldan-Valadez ◽  
Camilo Rios ◽  
David Cortez-Conradis ◽  
Rafael Favila ◽  
Sergio Moreno-Jimenez
Keyword(s):  
Diffusion Tensor Imaging ◽  
Discriminant Analysis ◽  
Glioblastoma Multiforme ◽  
Predictive Model ◽  
Predictive Accuracy ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Continuous Variables ◽  
Whole Brain ◽  
Axial Diffusivity

Abstract Background. Histological behavior of glioblastoma multiforme suggests it would benefit more from a global rather than regional evaluation. A global (whole-brain) calculation of diffusion tensor imaging (DTI) derived tensor metrics offers a valid method to detect the integrity of white matter structures without missing infiltrated brain areas not seen in conventional sequences. In this study we calculated a predictive model of brain infiltration in patients with glioblastoma using global tensor metrics. Methods. Retrospective, case and control study; 11 global DTI-derived tensor metrics were calculated in 27 patients with glioblastoma multiforme and 34 controls: mean diffusivity, fractional anisotropy, pure isotropic diffusion, pure anisotropic diffusion, the total magnitude of the diffusion tensor, linear tensor, planar tensor, spherical tensor, relative anisotropy, axial diffusivity and radial diffusivity. The multivariate discriminant analysis of these variables (including age) with a diagnostic test evaluation was performed. Results. The simultaneous analysis of 732 measures from 12 continuous variables in 61 subjects revealed one discriminant model that significantly differentiated normal brains and brains with glioblastoma: Wilks’ λ = 0.324, χ2 (3) = 38.907, p < .001. The overall predictive accuracy was 92.7%. Conclusions. We present a phase II study introducing a novel global approach using DTI-derived biomarkers of brain impairment. The final predictive model selected only three metrics: axial diffusivity, spherical tensor and linear tensor. These metrics might be clinically applied for diagnosis, follow-up, and the study of other neurological diseases.

Diffusion tensor imaging in hyperthyroidism: assessment of microstructural white matter abnormality with a tract-based spatial statistical analysis

2020 ◽  
Vol 61 (12) ◽  
pp. 1677-1683 ◽  
Author(s):  
Kerim Aslan ◽  
Hediye Pinar Gunbey ◽  
Sumeyra Cortcu ◽  
Onur Ozyurt ◽  
Ugur Avci ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Corpus Callosum ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Imaging Study ◽  
Internal Capsule ◽  
Control Group ◽  
Corona Radiata ◽  
Microstructural Alterations

Background Metabolic, morphological, and functional brain changes associated with a neurological deficit in hyperthyroidism have been observed. However, changes in microstructural white matter (WM), which can explain the underlying pathophysiology of brain dysfunctions, have not been researched. Purpose To assess microstructural WM abnormality in patients with untreated or newly diagnosed hyperthyroidism using tract-based spatial statistics (TBSS). Material and Methods Eighteen patients with hyperthyroidism and 14 age- and sex-matched healthy controls were included in this study. TBSS were used in this diffusion tensor imaging study for a whole-brain voxel-wise analysis of fractional anisotropy, mean diffusivity, axial diffusivity (AD), and radial diffusivity (RD) of WM. Results When compared to the control group, TBSS showed a significant increase in the RD of the corpus callosum, anterior and posterior corona radiata, posterior thalamic radiation, cingulum, superior longitudinal fasciculus, and the retrolenticular region of the internal capsule in patients with hyperthyroidism ( P < 0.05), as well as a significant decrease in AD in the anterior corona radiata and the genu of corpus callosum ( P < 0.05). Conclusion This study showed that more regions are affected by the RD increase than the AD decrease in the WM tracts of patients with hyperthyroidism. These preliminary results suggest that demyelination is the main mechanism of microstructural alterations in the WM of hyperthyroid patients.

scholarly journals White Matter Integrity Predicts Delay Discounting Behavior in 9- to 23-Year-Olds: A Diffusion Tensor Imaging Study

2009 ◽  
Vol 21 (7) ◽  
pp. 1406-1421 ◽  
Author(s):  
Elizabeth A. Olson ◽  
Paul F. Collins ◽  
Catalina J. Hooper ◽  
Ryan Muetzel ◽  
Kelvin O. Lim ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Delay Discounting ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Imaging Study ◽  
Temporal Lobes ◽  
Brain White Matter ◽  
Independent Effects ◽  
Age Range

Healthy participants (n = 79), ages 9–23, completed a delay discounting task assessing the extent to which the value of a monetary reward declines as the delay to its receipt increases. Diffusion tensor imaging (DTI) was used to evaluate how individual differences in delay discounting relate to variation in fractional anisotropy (FA) and mean diffusivity (MD) within whole-brain white matter using voxel-based regressions. Given that rapid prefrontal lobe development is occurring during this age range and that functional imaging studies have implicated the prefrontal cortex in discounting behavior, we hypothesized that differences in FA and MD would be associated with alterations in the discounting rate. The analyses revealed a number of clusters where less impulsive performance on the delay discounting task was associated with higher FA and lower MD. The clusters were located primarily in bilateral frontal and temporal lobes and were localized within white matter tracts, including portions of the inferior and superior longitudinal fasciculi, anterior thalamic radiation, uncinate fasciculus, inferior fronto-occipital fasciculus, corticospinal tract, and splenium of the corpus callosum. FA increased and MD decreased with age in the majority of these regions. Some, but not all, of the discounting/DTI associations remained significant after controlling for age. Findings are discussed in terms of both developmental and age-independent effects of white matter organization on discounting behavior.

Structural brain changes after 4 wk of unilateral strength training of the lower limb

2013 ◽  
Vol 115 (2) ◽  
pp. 167-175 ◽  
Author(s):  
H. S. Palmer ◽  
A. K. Håberg ◽  
M. S. Fimland ◽  
G. M. Solstad ◽  
V. Moe Iversen ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Strength Training ◽  
Isometric Contraction ◽  
Healthy Adult ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Cortical Activation ◽  
Maximum Voluntary Isometric Contraction ◽  
The Right ◽  
Unilateral Strength Training

Strength training enhances muscular strength and neural drive, but the underlying neuronal mechanisms remain unclear. This study used magnetic resonance imaging (MRI) to identify possible changes in corticospinal tract (CST) microstructure, cortical activation, and subcortical structure volumes following unilateral strength training of the plantar flexors. Mechanisms underlying cross-education of strength in the untrained leg were also investigated. Young, healthy adult volunteers were assigned to training ( n = 12) or control ( n = 9) groups. The 4 wk of training consisted of 16 sessions of 36 unilateral isometric plantar flexions. Maximum voluntary isometric contraction torque was tested pre- and posttraining. MRI investigation included a T1-weighted scan, diffusion tensor imaging and functional MRI. Probabilistic fiber tracking of the CST was performed on the diffusion tensor imaging images using a two-regions-of-interest approach. Fractional anisotropy and mean diffusivity were calculated for the left and right CST in each individual before and after training. Standard functional MRI analyses and volumetric analyses of subcortical structures were also performed. Maximum voluntary isometric contraction significantly increased in both the trained and untrained legs of the training group, but not the control group. A significant decrease in mean diffusivity was found in the left CST following strength training of the right leg. No significant changes were detected in the right CST. No significant changes in cortical activation were observed following training. A significant reduction in left putamen volume was found after training. This study provides the first evidence for strength training-related changes in white matter and putamen in the healthy adult brain.

Abstract P59: Peak Width of Skeletonized Mean Diffusivity Outperforms Other Diffusion Tensor Imaging Metrics as Biomarker for Cognition in Memory-Clinic Subjects With Cerebral Amyloid Angiopathy

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Maria Clara Zanon Zotin ◽  
Dorothee Schoemaker ◽  
Valentina Perosa ◽  
Martin Bretzner ◽  
Lukas Sveikata ◽  
...  
Keyword(s):  
Executive Function ◽  
Diffusion Tensor Imaging ◽  
Linear Regression ◽  
Processing Speed ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Amyloid Angiopathy ◽  
Peak Width ◽  
Memory Clinic ◽  
Cerebral Amyloid

Introduction: Peak width of skeletonized mean diffusivity (PSMD) is a novel fully automated diffusion tensor imaging (DTI) marker that has been consistently associated with cognition in cerebral small vessel disease (SVD) cohorts, including cerebral amyloid angiopathy (CAA). We hypothesized that PSMD would be more strongly associated with cognitive performance compared to other conventional DTI metrics in our CAA sample. Methods: We recruited non-demented subjects with probable-CAA from a single-center memory-clinic cohort. We analyzed structural MRIs to compute a validated CAA burden score (0-6 points scale, based on the following MRI features: lobar microbleeds, superficial siderosis, perivascular spaces in centrum semiovale, and white matter hyperintensities). PSMD was obtained using a freely available script ( www.psmd-marker.com ). We used the same skeleton-mask to compute: mean of skeletonized mean diffusivity (mean MD) and mean of skeletonized fractional anisotropy (mean FA). We used linear regression analyses to explore relationships with CAA burden score and cognitive composite scores (processing speed, executive function, memory, and language - z-scores adjusted for age, sex and education level). Results: We included 43 subjects (mean age 74.4 ± 5.9 years; 48.8% female; PSMD median [IQR]: 4.05 [3.58 - 4.80] x 10 -4 mm 2 /s). In linear regression models adjusting for age, DTI metrics were significantly associated with CAA burden score (mean FA: β = -0.563, Adj. R 2 : 0.27; p < 0.001; mean MD: β = 0.581; Adj. R 2 : 0.32; p < 0.001; PSMD: β = 0.364, Adj. R 2 : 0.12; p = 0.018). PSMD was significantly associated with cognitive performance, specifically in the domains of executive function ( β = -0.568; Adj. R 2 : 0.25; p < 0.001) and processing speed ( β = -0.447; Adj. R 2 : 0.19; p = 0.004). Other DTI metrics were not significantly associated with cognitive scores. Conclusion: In this CAA sample, all DTI metrics were associated with CAA burden scores, however, only PSMD was significantly associated with cognition, in domains that are commonly affected in vascular cognitive impairment. Our results warrant confirmation in larger samples, but support PSMD as biomarker for cognition in CAA, outperforming other conventional DTI metrics.

Diffusion tensor imaging of cerebral white matter in patients with myotonic dystrophy

2005 ◽  
Vol 46 (1) ◽  
pp. 104-109 ◽  
Author(s):  
H. Fukuda ◽  
J. Horiguchi ◽  
C. Ono ◽  
T. Ohshita ◽  
J. Takaba ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Myotonic Dystrophy ◽  
Normal Control ◽  
Diffusion Tensor ◽  
Age At Onset ◽  
Mean Diffusivity ◽  
Magnetic Resonance Images ◽  
Microstructural Changes ◽  
Control Subjects

Purpose: To determine whether myotonic dystrophy (MyD) patients have diffusion tensor abnormalities suggestive of microstructural changes in normal‐appearing white matter (NAWM). Material and Methods: Conventional and diffusion tensor magnetic resonance images of the brain were obtained in 19 MyD patients and 19 age‐matched normal control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) values were calculated in white matter lesions (WMLs) and NAWM in MyD patients and in the white matter of normal control subjects. Differences between WML and NAWM values and between MyD patient and control subject values were analyzed statistically. Results: Significantly lower FA and higher MD values were found in all regions of interest in the NAWM of MyD patients than in the white matter of control subjects ( P<0.01), as well as significantly lower FA and higher MD values in WMLs than in NAWM of MyD patients ( P<0.05). There was no significant correlation of mean FA or MD values in NAWM with patient age, age at onset, or duration of illness ( P>0.1). Conclusion: Diffusion tensor imaging analysis suggests the presence of diffuse microstructural changes in NAWM of MyD patients that may play an important role in the development of disability.

scholarly journals Diffusion Tensor Imaging of the Kidneys: Influence of b-Value and Number of Encoding Directions on Image Quality and Diffusion Tensor Parameters

2013 ◽  
Vol 3 ◽  
pp. 53 ◽  
Author(s):  
Natalie C. Chuck ◽  
Günther Steidle ◽  
Iris Blume ◽  
Michael A. Fischer ◽  
Daniel Nanz ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Image Quality ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Renal Medulla ◽  
Whole Body ◽  
Acquisition Time ◽  
Data Sets ◽  
B Values

Objectives: The purpose of this study was to evaluate to which degree investment of acquisition time in more encoding directions leads to better image quality (IQ) and what influence the number of encoding directions and the choice of b-values have on renal diffusion tensor imaging (DTI) parameters. Material and Methods: Eight healthy volunteers (32.3 y ± 5.1 y) consented to an examination in a 1.5T whole-body MR scanner. Coronal DTI data sets of the kidneys were acquired with systematic variation of b-values (50, 150, 300, 500, and 700 s/mm2) and number of diffusion-encoding directions (6, 15, and 32) using a respiratory-triggered echo-planar sequence (TR/TE 1500 ms/67 ms, matrix size 128 × 128). Additionally, two data sets with more than two b-values were acquired (0, 150, and 300 s/mm2 and all six b-values). Parametrical maps were calculated on a pixel-by-pixel basis. Image quality was determined with a reader score. Results: Best IQ was visually assessed for images acquired with 15 and 32 encoding directions, whereas images acquired with six directions had significantly lower IQ ratings. Image quality, fractional anisotropy, and mean diffusivity only varied insignificantly for b-values between 300 and 500 s/mm2. In the renal medulla fractional anisotropy (FA) values between 0.43 and 0.46 and mean diffusivity (MD) values between 1.8-2.1 × 10-3 mm2/s were observed. In the renal cortex, the corresponding ranges were 0.24-0.25 (FA) and 2.2-2.8 × 10-3 mm2/s (MD). Including b-values below 300 s/mm2, notably higher MD values were observed, while FA remained constant. Susceptibility artifacts were more prominent in FA maps than in MD maps. Conclusion: In DTI of the kidneys at 1.5T, the best compromise between acquisition time and resulting image quality seems the application of 15 encoding directions with b-values between 300 and 500 s/mm2. Including lower b-values allows for assessment of fast diffusing spin components.

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