Evaluation of diffusion parameters and T2 values of the masseter muscle during jaw opening, clenching, and rest

2012 ◽  
Vol 53 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Tomoko Shiraishi ◽  
Toru Chikui ◽  
Daisuke Inadomi ◽  
Toyohiro Kagawa ◽  
Kazunori Yoshiura ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Root Apex ◽  
Diffusion Parameters ◽  
Skeletal Muscle Contraction ◽  
Jaw Opening ◽  
Significant Difference ◽  
Diffusion Tensor Images ◽  
Mandibular Notch ◽  
Jaw Position ◽  
Lower Site

Background Diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) can be used to evaluate changes that accompany skeletal muscle contraction. Purpose To investigate whether jaw opening or closure affect the diffusion parameters of the masseter muscles (MMs). Material and Methods Eleven healthy volunteers were evaluated. Diffusion-tensor images were acquired to obtain the primary (λ1), secondary (λ2), and tertiary eigenvalues (λ3). We estimated these parameters at three different locations: at the level of the mandibular notch for the superior site, the level of the mandibular foramen for the middle site, and the root apex of the mandibular molars for the inferior site. Results Both λ2 and λ3 during jaw opening were significantly lower than that at rest at the superior ( P = 0.006, P < 0.0001, respectively) and middle site ( P = 0.004, P = 0.0001, respectively); however, the change in λ1 was not significant. At the lower site, no parameter was significantly different at rest and during jaw opening. There was no significant difference in T2 between at rest (40.3 ± 4.4 ms) and during jaw opening (39.2 ± 2.7 ms; P = 0.12). The changes induced by jaw closure were marked at the inferior site. In the middle and inferior sites, the three eigenvalues were increased by jaw closure, and the changes in λ1 ( P = 0.0145, P = 0.0107, respectively) and λ2 ( P = 0.0003, P = 0.0001) were significant (especially λ2). Conclusion The eigenvalues for diffusion of the MM were sensitive to jaw position. The recruitment of muscle fibers, specific to jaw position, reflects the differences in changes in muscle diffusion parameters.

scholarly journals Evaluation of White Matter Tracts in Autistic Individuals: A Review of Diffusion Tensor Imaging Studies

2021 ◽  
Author(s):  
Reihane Faraji ◽  
Zahra Khandan khademreza ◽  
Soheila Sharifian ◽  
Hoda Zare
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Autism Spectrum ◽  
Social Deficits ◽  
White Matter Tracts ◽  
Functional Connections ◽  
Significant Difference ◽  
Efficient Communication ◽  
Diffusion Tensor Images ◽  
The Brain

Introduction: Many cognitive and social deficits in autism are caused by abnormal functional connections between brain networks, which are manifested by impaired integrity of white matter tracts. White matter tracts are like the "highways" of the brain, which allow fast and efficient communication in different areas of the brain. The purpose of this article is to review the results of autism studies that have used diffusion tensor images (DTI). Diffusion tensor images is a neuroimaging technique to examine the integrity of tracts. Conclusion: The results of these studies suggest that neural tracts can be abnormal in people with Autism spectrum disorder (ASD) due to impaired white matter integrity. Thus, changes in these tracts in the brains of people with ASD are helpful in identifying individual differences. Although most studies have reported decreased FA and increased MD, RD, and AD in white matter tracts, some studies have reported increased FA or no significant difference between the control and autistic groups.

Associations between clinical outcome and tractography based on navigated transcranial magnetic stimulation in patients with language-eloquent brain lesions

2020 ◽  
Vol 132 (4) ◽  
pp. 1033-1042 ◽  
Author(s):  
Nico Sollmann ◽  
Alessia Fratini ◽  
Haosu Zhang ◽  
Claus Zimmer ◽  
Bernhard Meyer ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Brain Tumors ◽  
Risk Stratification ◽  
Magnetic Stimulation ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
Navigated Transcranial Magnetic Stimulation ◽  
Language Mapping ◽  
Significant Difference ◽  
Related Pathway

OBJECTIVENavigated transcranial magnetic stimulation (nTMS) in combination with diffusion tensor imaging fiber tracking (DTI FT) is increasingly used to locate subcortical language-related pathways. The aim of this study was to establish nTMS-based DTI FT for preoperative risk stratification by evaluating associations between lesion-to-tract distances (LTDs) and aphasia and by determining a cut-off LTD value to prevent surgery-related permanent aphasia.METHODSFifty patients with left-hemispheric, language-eloquent brain tumors underwent preoperative nTMS language mapping and nTMS-based DTI FT, followed by tumor resection. nTMS-based DTI FT was performed with a predefined fractional anisotropy (FA) of 0.10, 0.15, 50% of the individual FA threshold (FAT), and 75% FAT (minimum fiber length [FL]: 100 mm). The arcuate fascicle (AF), superior longitudinal fascicle (SLF), inferior longitudinal fascicle (ILF), uncinate fascicle (UC), and frontooccipital fascicle (FoF) were identified in nTMS-based tractography, and minimum LTDs were measured between the lesion and the AF and between the lesion and the closest other subcortical language-related pathway (SLF, ILF, UC, or FoF). LTDs were then associated with the level of aphasia (no/transient or permanent surgery-related aphasia, according to follow-up examinations).RESULTSA significant difference in LTDs was observed between patients with no or only surgery-related transient impairment and those who developed surgery-related permanent aphasia with regard to the AF (FA = 0.10, p = 0.0321; FA = 0.15, p = 0.0143; FA = 50% FAT, p = 0.0106) as well as the closest other subcortical language-related pathway (FA = 0.10, p = 0.0182; FA = 0.15, p = 0.0200; FA = 50% FAT, p = 0.0077). Patients with surgery-related permanent aphasia showed the lowest LTDs in relation to these tracts. Thus, LTDs of ≥ 8 mm (AF) and ≥ 11 mm (SLF, ILF, UC, or FoF) were determined as cut-off values for surgery-related permanent aphasia.CONCLUSIONSnTMS-based DTI FT of subcortical language-related pathways seems suitable for risk stratification and prediction in patients suffering from language-eloquent brain tumors. Thus, the current role of nTMS-based DTI FT might be expanded, going beyond the level of being a mere tool for surgical planning and resection guidance.

Diffusion tensor imaging analysis in scrub typhus meningoencephalitis to determine the alteration of microstructural subcortical white-matter integrity

2020 ◽  
pp. 197140092098031
Author(s):  
Pranjal Phukan ◽  
Kalyan Sarma ◽  
Aman Yusuf Khan ◽  
Bhupen Barman ◽  
Md Jamil ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Scrub Typhus ◽  
Diffusion Tensor ◽  
Neuronal Degeneration ◽  
Central Nervous System Involvement ◽  
Subcortical White Matter ◽  
White Matter Integrity ◽  
Conventional Mri ◽  
Significant Difference

Background and purpose Magnetic resonance imaging (MRI) of the brain in scrub typhus meningoencephalitis is non-specific, and in the majority of the cases, conventional MRI fails to detect any abnormality. However, autopsy reports depict central nervous system involvement in almost all patients. There is therefore a need for research on the quantitative assessment of brain parenchyma that can detect microstructural abnormalities. The study aimed to assess the microstructural integrity changes of scrub typhus meningoencephalitis by using different diffusion tensor imaging (DTI) parameters. Methods This was a retrospective analysis of scrub typhus meningoencephalitis. Seven patients and seven age- and sex-matched healthy controls were included. Different DTI parameters such as apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative anisotropy (RA), trace, volume ratio (VR) and geodesic anisotropy (GA) were obtained from six different regions of subcortical white matter at the level of the centrum semiovale. Intergroup significant difference was determined by one-way analysis of variance followed by Tukey’s post hoc test. Receiver operating characteristic curves were constructed to determine the accuracy of the DTI matrices. Results There was a significant decrease in FA, RA and GA as well as an increase in ADC and VR in the subcortical white matter in patients with scrub typhus meningoencephalitis compared to controls ( p < 0.001). The maximum sensitivity of the DTI parameters was 85.7%, and the maximum specificity was 81%. Conclusion There was an alteration of subcortical white-matter integrity in scrub typhus meningoencephalitis that represents the axonal degeneration, myelin breakdown and neuronal degeneration. DTI may be a useful tool to detect white-matter abnormalities in scrub typhus meningoencephalitis in clinical practice, particularly in patients with negative conventional MRI.

Transmural heterogeneity of diffusion anisotropy in the sheep myocardium characterized by MR diffusion tensor imaging

2007 ◽  
Vol 293 (4) ◽  
pp. H2377-H2384 ◽  
Author(s):  
Yi Jiang ◽  
Julius M. Guccione ◽  
Mark B. Ratcliffe ◽  
Edward W. Hsu
Keyword(s):  
Diffusion Tensor Imaging ◽  
Volume Fraction ◽  
Diffusion Tensor ◽  
Extracellular Volume ◽  
Extracellular Volume Fraction ◽  
Left Ventricular ◽  
Fiber Direction ◽  
Significant Difference ◽  
Mr Diffusion ◽  
Mr Diffusion Tensor Imaging

The orientation of MRI-measured diffusion tensor in the myocardium has been directly correlated to the tissue fiber direction and widely characterized. However, the scalar anisotropy indexes have mostly been assumed to be uniform throughout the myocardial wall. The present study examines the fractional anisotropy (FA) as a function of transmural depth and circumferential and longitudinal locations in the normal sheep cardiac left ventricle. Results indicate that FA remains relatively constant from the epicardium to the midwall and then decreases (25.7%) steadily toward the endocardium. The decrease of FA corresponds to 7.9% and 12.9% increases in the secondary and tertiary diffusion tensor diffusivities, respectively. The transmural location of the FA transition coincides with the location where myocardial fibers run exactly circumferentially. There is also a significant difference in the midwall-endocardium FA slope between the septum and the posterior or lateral left ventricular free wall. These findings are consistent with the cellular microstructure from histological studies of the myocardium and suggest a role for MR diffusion tensor imaging in characterization of not only fiber orientation but, also, other tissue parameters, such as the extracellular volume fraction.

scholarly journals Multiple sclerosis and depressive manifestations: can diffusion tensor MR imaging help in the detection of microstructural white matter changes?

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Talaat A. Hassan ◽  
Shaima Fattouh Elkholy ◽  
Bahaa Eldin Mahmoud ◽  
Mona ElSherbiny
Keyword(s):  
Multiple Sclerosis ◽  
Depressive Symptoms ◽  
White Matter ◽  
Limbic System ◽  
Diffusion Tensor ◽  
Control Group ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Significant Difference ◽  
The Right

Abstract Background Multiple sclerosis is one of the commonest causes of neurological disability in middle-aged and young adults. Depression in MS patients can compromise cognitive functions, lead to suicide attempts, impair relationships and reduce compliance with disease-modifying treatments. The aim of this study was to investigate and compare the microstructural changes in the white matter tracts of the limbic system in MS patients with and those without depressive manifestations using a diffusion tensor imaging (DTI) technique. Methods This study included 40 patients who were divided into three groups. Group 1 comprised of 20 patients with relapsing-remitting MS with depressive symptoms and group 2 comprised 10 MS patients without symptoms of depression. The third group is a control group that included 10 age-matched healthy individuals. All patients underwent conventional MRI examinations and DTI to compare the fractional anisotropy (FA) values in the white matter tracts of the limbic system. Results We compared the DTI findings in MS patients with and those without depressive symptoms. It was found that patients with depression and MS exhibited a significant reduction in the FA values of the cingulum (P < 0.0111 on the right and P < 0.0142 on the left), uncinate fasciculus (P < 0.0001 on the right and P < 0.0076 on the left) and the fornix (P < 0.0001 on both sides). No significant difference was found between the FA values of the anterior thalamic radiations in both groups. Conclusion Patients with depression and MS showed more pronounced microstructural damage in the major white matter connections of the limbic pathway, namely, the uncinate fasciculus, cingulum and fornix. These changes can be detected by DTI as decreased FA values in depressed MS patients compared to those in non-depressed patients.

scholarly journals Direct segmentation of the major white matter tracts in diffusion tensor images

NeuroImage ◽  
2011 ◽  
Vol 58 (2) ◽  
pp. 458-468 ◽  
Author(s):  
Pierre-Louis Bazin ◽  
Chuyang Ye ◽  
John A. Bogovic ◽  
Navid Shiee ◽  
Daniel S. Reich ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
White Matter Tracts ◽  
Diffusion Tensor Images

scholarly journals Bayesian regularization of diffusion tensor images

Biostatistics ◽  
2006 ◽  
Vol 8 (4) ◽  
pp. 784-799 ◽  
Author(s):  
J. Frandsen ◽  
A. Hobolth ◽  
L. Ostergaard ◽  
P. Vestergaard-Poulsen ◽  
E. B. Vedel Jensen
Keyword(s):  
Diffusion Tensor ◽  
Bayesian Regularization ◽  
Diffusion Tensor Images

Increased muscle fiber fractional anisotropy value using diffusion tensor imaging after compression without fiber injury

2021 ◽  
pp. 028418512110582
Author(s):  
Takumi Yokohama ◽  
Motoyuki Iwasaki ◽  
Daisuke Oura ◽  
Sho Furuya ◽  
Yoshimasa Niiya
Keyword(s):  
Diffusion Tensor Imaging ◽  
Fractional Anisotropy ◽  
Muscle Tissue ◽  
Diffusion Tensor ◽  
Longitudinal Direction ◽  
Diffusion Parameters ◽  
Apparent Diffusion ◽  
The Mean ◽  
Magnetic Resonance Imaging Mri ◽  
Age Range

Background Recent studies have indicated that injuries such as muscle tears modify the microstructural integrity of muscle, leading to substantial alterations in measured diffusion parameters. Therefore, the fractional anisotropy (FA) value decreases. However, we hypothesized that soft tissue, such as muscle tissue, undergoes reversible changes under conditions of compression without fiber injury. Purpose To evaluate the FA change due to compression in muscle tissue without fiber injury. Material and Methods Diffusion tensor imaging (DTI) was performed on both feet of 10 healthy volunteers (mean age = 35.0 ± 10.39 years; age range = 23–52 years) using a 3.0-T magnetic resonance imaging (MRI) scanner with an eight-channel phased array knee coil. An MRI-compatible sphygmomanometer was applied to the individuals’ lower legs and individuals were placed in a compressed state. Then, rest intervals of 5 min were set in re-rest state after compression. The FA value, apparent diffusion coefficient (ADC), and eigenvalues (λ1, λ2, λ3) of the gastrocnemius and soleus muscle were measured at each state. Results The mean FA values increased in all muscles in a compressed state, while the mean λ3 decreased. In all muscles, significant differences were found between the rest and compressed states in terms of mean FA and λ3 ( P < 0.0001). Conclusion We confirmed the reversibility of the DTI metrics, which suggests that there was no muscle injury during this study. In cases of compression without fiber injury, the FA value increases, because fibers are strongly aligned in the longitudinal direction.

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