Mean Diffusivity

White matter damage and its contribution to clinical manifestations in patients with dementia have been increasingly recognized. To explore white matter changes in different types of dementia, we examined brain water diffusivity with diffusion tensor imaging (DTI). We measured fractional anisotropy and mean diffusivity of multiple white matter regions in patients with amnesic mild cognitive impairment (MCI, n = 10), Alzheimer's disease (AD, n = 30), subcortical ischemic vascular dementia (SIVD, n = 18), frontotemporal dementia (FTD, n = 7), and control subjects (n = 20). We performed pairwise comparisons in each region of interest between patients and controls. MCI patients showed diffusion tensor change (DTC) in the left anterior periventricular (PV) area, possibly in the right posterior PV area, and the genu of the corpus callosum. AD patients showed DTC in the corpus callosum, and in frontal and parieto-occipital subcortical and anterior PV areas. In SIVD patients, DTC occurred in the genu of the corpus callosum, and in bilateral frontal subcortical and PV areas. FTD patients differed from controls in showing DTC in the temporal and frontal subcortical areas, the genu of the corpus callosum and PV areas. The degree of DTC correlated with the clinical severity of dementia as assessed by the clinical dementia rating (CDR). Mean diffusivity was diffusely and positively associated with the CDR scores. Fractional anisotropy of the PV areas was negatively associated with the CDR scores, suggesting a critical role of the lateral cholinergic pathways.

Previous diffusion tensor imaging (DTI) studies indicated microstructural disruption of white matter in alcohol dependence. To investigate the microstructure of primary neurocircuitry involved in alcohol use disorders, the present study used Tract-Based Spatial Statistics (TBSS) of DTI measures as well as probabilistic tractography. Eleven recovering alcoholics in their first week of abstinence from alcohol were compared with ten light drinking controls; diffusion measures were correlated with measures of neurocognition and drinking severity. Regions characterized by low fractional anisotropy and high mean diffusivity included cortico-striatal fibers and those in frontal white matter and limbic pathways. Greater diffusion abnormalities in sections of commissural fibers (interhemispheric connections) were associated with stronger drinking severity, and lower fractional anisotropy measures in frontal and limbic fiber tracts correlated with lower visuospatial memory performance. These study findings provide direct evidence of compromised integrity of the motivational brain circuitry in alcohol use disorders. These abnormalities in fiber connections could be partially responsible for deficiencies in executive functions, behavioral regulation, and impulse control commonly described in alcohol dependence.

Previous diffusion tensor imaging (DTI) studies indicated microstructural disruption of white matter in alcohol dependence. To investigate the microstructure of primary neurocircuitry involved in alcohol use disorders, the present study used Tract-Based Spatial Statistics (TBSS) of DTI measures as well as probabilistic tractography. Eleven recovering alcoholics in their first week of abstinence from alcohol were compared with 10 light-drinking controls; diffusion measures were correlated with measures of neurocognition and drinking severity. Regions characterized by low fractional anisotropy and high mean diffusivity included cortico-striatal fibers and those in frontal white matter and limbic pathways. Greater diffusion abnormalities in sections of commissural fibers (inter-hemispheric connections) were associated with greater drinking severity, and lower fractional anisotropy measures in frontal and limbic fiber tracts correlated with lower visuospatial memory performance. These s...

We introduce an automatic method that we call tract-based morphometry, or TBM, for measurement and analysis of diffusion MRI data along white matter fiber tracts. Using subject-specific tractography bundle segmentations, we generate an arc length parameterization of the bundle with point correspondences across all fibers and all subjects, allowing tract-based measurement and analysis. In this paper we present a quantitative comparison of fiber coordinate systems from the literature and we introduce an improved optimal match method that reduces spatial distortion and improves intra-and inter-subject variability of FA measurements. We propose a method for generating arc length correspondences across hemispheres, enabling a TBM study of interhemispheric diffusion asymmetries in the arcuate fasciculus (AF) and cingulum bundle (CB). The results of this study demonstrate that TBM can detect differences that may not be found by measuring means of scalar invariants in entire tracts, such as the mean diffusivity (MD) differences found in AF. We report TBM results of higher fractional anisotropy (FA) in the left hemisphere in AF (caused primarily by lower λ 3 , the smallest eigenvalue of the diffusion tensor, in the left AF), and higher left hemisphere FA in CB (related to higher λ 1 , the largest eigenvalue of the diffusion tensor, in the left CB). By mapping the significance levels onto the tractography trajectories for each structure, we demonstrate the anatomical locations of the interhemispheric differences. The TBM approach brings analysis of DTI data into the clinically and neuroanatomically relevant framework of the tract anatomy.

A key question in diffusion imaging is how many diffusion-weighted images suffice to provide adequate signal-to-noise ratio (SNR) for studies of fiber integrity. Motion, physiological effects, and scan duration all affect the achievable SNR in real brain images, making theoretical studies and simulations only partially useful. We therefore scanned 50 healthy adults with 105-gradient high-angular resolution diffusion imaging (HARDI) at 4T. From gradient image subsets of varying size (6 ≤ N ≤ 94) that optimized a spherical angular distribution energy, we created SNR plots (versus gradient numbers) for seven common diffusion anisotropy indices: fractional and relative anisotropy (FA, RA), mean diffusivity (MD), volume ratio (VR), geodesic anisotropy (GA), its hyperbolic tangent (tGA), and generalized fractional anisotropy (GFA). SNR, defined in a region of interest in the corpus callosum, was near-maximal with 58, 66, and 62 gradients for MD, FA, and RA, respectively, and with about 55 gradients for GA and tGA. For VR and GFA, SNR increased rapidly with more gradients. SNR was optimized when the ratio of diffusion-sensitized to non-sensitized images was 9.13 for GA and tGA, 10.57 for FA, 9.17 for RA, and 26 for MD and VR. In orientation density functions modeling the HARDI signal as a continuous mixture of tensors, the diffusion profile reconstruction accuracy rose rapidly with additional gradients. These plots may help in making trade-off decisions when designing diffusion imaging protocols.

Abnormalities in fronto-limbic-striatal white matter (WM) have been reported in bipolar disorder (BD), but results have been inconsistent across studies. Furthermore, there have been no detailed investigations as to whether acute mood states contribute to microstructural changes in WM tracts. In order to compare fiber density and structural integrity within WM tracts between BD depression and remission, whole-brain fractional anisotropy (FA) and mean diffusivity (MD) were assessed in 37 bipolar I disorder (BD-I) patients (16 depressed and 21 remitted), and 26 healthy individuals with diffusion tensor imaging. Significantly decreased FA and increased MD in bilateral prefronto-limbicstriatal white matter and right inferior fronto-occipital, superior and inferior longitudinal fasciculi were shown in all BD-I patients versus controls, as well as in depressed BD-I patients compared to both controls and remitted BD-I patients. Depressed BD-I patients also exhibited increased FA in the ventromedial prefrontal cortex. Remitted BD-I patients did not differ from controls in FA or MD. These findings suggest that BD-I depression may be associated with acute microstructural WM changes.

Memory impairment is one of the most commonly reported effects of cannabis use, especially among those who initiate use earlier, perhaps due to the effects of delta-9- tetrahydrocannabinol on cannabinoid (CB1) receptors in the brain. Studies have increasingly investigated whether cannabis use is associated with impairments in verbal memory, and with alterations in brain structures underlying verbal memory. The uncinate fasciculus (UF), a long-range white matter tract, connects regions with densely localized CB1 receptors that are important in verbal memory. This study investigated the impact of cannabis use on UF structures and its association with memory performance in young adult cannabis users (CU) and non-using controls (CON).Nineteen CU and 22 CON completed a verbal memory task and a neuroimaging protocol, in which diffusion tensor imaging and structural scans were collected. We compared memory performance, diffusion and tractography measures of the UF, and cortical thickness o...

Introduction: Diffusion tensor imaging (DTI) studies of stroke patients have consistently demonstrated marked reductions of fractional anisotropy (FA) within the lesion (~29-70% FA decreases) or regions remote (upstream or downstream) from the infarct (~8-40% FA reductions) over a time course of 2 days to 1 year [1,2]. However, DTI studies of acute stroke are more variable. Increased FA within the first day of stroke has been observed, but this is not as consistent as several others report reductions, or no change in FA over the same time frame [3,4]. A recent cross-sectional DTI study of ischemic white matter (WM) regions showed that FA was only significantly elevated (up to 25%) ≤7h of symptom onset, but consistently reduced (~15% declines) from 8-34h after stroke [5]. Serial DTI scans after ischemic stroke in individual patients may help clarify the discrepancies in some of those previous reports. Previous longitudinal DTI studies of human ischemic stroke that include time points of less than 24h have primarily focused on demonstrating the subsequent reductions of FA that occur at 1 week and several months post symptom onset [4,6]. Serial DTI reports of human stroke that characterize changes in diffusion anisotropy within 24h of stroke onset are non-existent. Mean diffusivity (MD) is consistently low during the first day of stroke; on the other hand, FA may yield discriminating data on the microstructural status of tissue within that time frame. We aimed to characterize serial FA changes during the hyperacute (≤7h) and acute (21.5-29h) phases of human stroke. Deep and subcortical WM and deep and cortical GM regions within the infarcts were analyzed individually due to the known variability in normal FA values within these regions as well as to assess whether there are different evolution patterns for the anisotropic water diffusion. Methods: Thirteen patients (6M, 7F; age range= 45-80 years) presenting with an ischemic stroke were initially scanned on a Siemens 1.5T Sonata scanner equipped with an 8-element head RF coil within 2.5-7h of symptom onset (median of 5h), and then subsequently scanned within 21.5-29h for a follow-up session (median of 26h). Modified SENSE based DTI (R=2 and 24 reference lines) was performed with: TR / TE / NEX = 2.5s / 81ms / 8, 96x128 matrix, 195x260 mm rectangular FOV with R-L phase-encode direction, and 20 3-mm thick contiguous axial slices aligned with the AC-PC, b=0 s/mm 2 and six sets with b=1000 s/mm 2 . The 20 3-mm thick contiguous slices for DTI were centered on the lesion identified on conventional diffusion-weighted images. The acquisition time was 2 min 37 s for DTI. Raw data were post-processed off-line to yield maps of the eigenvalues λ 1 , λ 2 , and λ 3 , MD and FA. Discrete WM and GM regions within the ischemic lesion (defined by ≥30% drop in MD relative (r) to the contralateral side) were traced using a free-hand Region-of-interest (ROI) method with the aid of the FA and MD maps, as well as the isotropic DW (b=1000) images separately for individual patient scans from the hyperacute and acute periods. A semi-automated method was employed to threshold the MD maps and all ROI traces were cross-checked with b=1000 images to avoid inclusion of any visible sulcal spaces. This was particularly important in cases where ROIs adjacent to cerebrospinal fluid filled sulcal spaces such as subcortical WM and cortical GM were part of the ischemic core. Measurements of FA, λ 1 , λ 2 , λ 3 , and T2-weighted signal intensity (measured on b=0 images) of the corresponding WM and GM regions in the contralateral hemisphere were used as a reference to yield relative parameters. Data were separated into categories of deep WM, subcortical WM, deep GM and cortical GM. Relative (ipsilateral/contralateral) values for each ROI measurement per patient were averaged over all patients within a distinct scanning period, with respect to the 4 tissues. Paired t-tests were used to examine differences between the ipsilateral and contralateral MD, FA, λ 1 , λ 2 , λ 3 and T2-wt signal intensity (p<0.05).

Background Diffusion tensor imaging (DTI) is a non-invasive MRI technique that has been used to quantify CNS abnormalities in various pathologic conditions. This study was designed to quantify the anisotropic diffusion properties in the brain of neonatal rats with hydrocephalus (HCP) and to investigate association between DTI measurements and cytopathology. Methods DTI data were acquired between postnatal day 7 (P7) and P12 in 12 rats with HCP induced at P2 and in 15 age-matched controls. Animals were euthanized at P11 or P22/P23 and brains were processed with immunohistochemistry for glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule (Iba-1), and luxol fast blue (LFB) to assess astrocytosis, microglial reactivity and degree of myelination, respectively. Results Hydrocephalic rats were consistently found to have an abnormally low (at corrected p-level of &lt;0.05) fractional anisotropy (FA) value and an abnormally high mean diffusivity (MD) value in the...

We aimed to develop a machine learning model for diagnostic classification in late-life major depression based on an advanced whole brain white matter segmentation framework. Twenty six late-life depression and 12 never depressed individuals aged &gt; 55 years, matched for age, MMSE, and education underwent diffusion tensor magnetic resonance imaging and multi-contrast, multi-atlas segmentation in MRIcloud. Fractional anisotropy volume, mean fractional anisotropy, trace, axial and radial diffusivity extracted from 146 white matter parcels were used to train and test the AdaBoost classifier using 12-fold cross validation. Performance was evaluated using accuracy, balanced accuracy, precision, and recall, F1-score and area under the receiver operator characteristic curve. Statistical significance of the classifier was assessed using standard label permutation and area under the receiver operator characteristic curve scores’ comparison. The classifier achieved a balanced accuracy, of 7...

Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are crucial in modern neurological diagnostics, enabling detailed analysis of brain structures and connectivity. This article presents a comprehensive approach to analysing MRI images using advanced tools such as the FSL software library. The proposed method leverages distributed web systems to enhance the scalability and accessibility of image processing and analysis across multiple medical facilities. Key steps, including noise reduction, artefact removal, and tensor reconstruction, are performed to improve diagnostic accuracy. Additionally, metrics such as fractional anisotropy (FA), mean diffusivity (MD), and axial diffusivity (AD) are evaluated to detect microstructural brain abnormalities. The integration of distributed web technologies facilitates real-time collaboration between specialists, accelerating diagnostic processes and enabling cross-hospital data sharing. This study highlights the potential of combining cutting-edge imaging techniques with scalable digital infrastructures to optimise medical decision-making and improve patient outcomes.

Aging is associated with declining cognitive performance as well as structural changes in brain gray and white matter (WM). The WM deterioration contributes to a disconnection among distributed brain networks and may thus mediate age-related cognitive decline. The present diffusion tensor imaging (DTI) study investigated age-related differences in WM microstructure and their relation to cognition (episodic memory, visuospatial processing, fluency, and speed) in a large group of healthy subjects (n = 287) covering 6 decades of the human life span. Age related decreases in fractional anisotropy (FA) and increases in mean diffusivity (MD) were observed across the entire WM skeleton as well as in specific WM tracts, supporting the WM degeneration hypothesis. The anterior section of the corpus callosum was more susceptible to aging compared to the posterior section, lending support to the anterior-posterior gradient of WM integrity in the corpus callosum. Finally, and of critical interest, WM integrity differences were found to mediate age-related reductions in processing speed but no significant mediation was found for episodic memory, visuospatial ability, or fluency. These findings suggest that compromised WM integrity is not a major contributing factor to declining cognitive performance in normal aging. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

We present a new standard atlas of the human brain based on magnetic resonance images. The atlas was generated using unbiased population registration from high-resolution images obtained by multichannel-coil acquisition at 3T in a group of 24 normal subjects. The final atlas comprises three anatomical channels (T 1 -weighted, early and late spin echo), three diffusion-related channels (fractional anisotropy, mean diffusivity, diffusion-weighted image), and three tissue probability maps (CSF, gray matter, white matter). The atlas is dynamic in that it is implicitly represented by nonrigid transformations between the 24 subject images, as well as distortion-correction alignments between the image channels in each subject. The atlas can, therefore, be generated at essentially arbitrary image resolutions and orientations (e.g., AC/PC aligned), without compounding interpolation artifacts. We demonstrate in this paper two different applications of the atlas: (a) region definition by label propagation in a fiber tracking study is enabled by the increased sharpness of our atlas compared with other available atlases, and (b) spatial normalization is enabled by its average shape property. In summary, our atlas has unique features and will be made available to the scientific community as a resource and reference system for future imaging-based studies of the human brain.

We present a new standard atlas of the human brain based on magnetic resonance images. The atlas was generated using unbiased population registration from high-resolution images obtained by multichannel-coil acquisition at 3T in a group of 24 normal subjects. The final atlas comprises three anatomical channels (T 1 -weighted, early and late spin echo), three diffusion-related channels (fractional anisotropy, mean diffusivity, diffusion-weighted image), and three tissue probability maps (CSF, gray matter, white matter). The atlas is dynamic in that it is implicitly represented by nonrigid transformations between the 24 subject images, as well as distortion-correction alignments between the image channels in each subject. The atlas can, therefore, be generated at essentially arbitrary image resolutions and orientations (e.g., AC/PC aligned), without compounding interpolation artifacts. We demonstrate in this paper two different applications of the atlas: (a) region definition by label propagation in a fiber tracking study is enabled by the increased sharpness of our atlas compared with other available atlases, and (b) spatial normalization is enabled by its average shape property. In summary, our atlas has unique features and will be made available to the scientific community as a resource and reference system for future imaging-based studies of the human brain.

Tensor Imaging (DTI) that acquires axial (transverse) images of the cervical spinal cord. The DTI images depict axonal fiber orientation, enable quantification of diffusion characteristics along the spinal cord, and have the potential to demonstrate the connectivity of cord white matter tracts. Because of the high sensitivity to motion of diffusion-weighted magnetic resonance imaging and the small size of the spinal cord, a fast imaging method with high in-plane resolution was developed. Images were acquired with a single-shot EPI technique, named ZOOM-EPI (zonally magnified oblique multislice echo planar imaging), which selects localized areas and reduces artefacts caused by susceptibility changes between soft tissue and the adjacent vertebrae. Cardiac gating was used to reduce pulsatile flow artefacts from the surrounding cerebrospinal fluid. Voxel resolution was 1.25 ؋ 1.25 mm 2 in-plane with 5-mm slice thickness. Both the mean diffusivity (MD) and the fractional anisotropy (FA) indices of the cervical spinal cord were measured. The FA index demonstrated high anisotropy of the spinal cord with an average value of 0.61 ؎ 0.05 (highest value of 0.66 ؎ 0.03 at C3), comparable to white matter tracts in the brain. The diffusivity components parallel and orthogonal to the longitudinal axes of the cord were ʈ ‫؍‬ (1648 ؎ 123) ؋ 10 ؊6 mm 2 s ؊1 and Ќ ‫؍‬ (570 ؎ 47) ؋ 10 ؊6 mm 2 s ؊1 , respectively. The high axial resolution allowed preliminary evaluation of fiber connectivity using the fast-marching tractography algorithm, which generated traces of fiber paths consistent with the well-known cord anatomy.

Magnetic resonance diffusion tensor imaging (DTI) has revealed the disruption of brain white matter microstructure in normal aging and alcoholism undetectable with conventional structural MR imaging. The metrics of DTI can be useful in establishing the nature of the observed microstructural aberrations. Abnormally low fractional anisotropy (FA), a measure of diffusion orientation and coherence, may result from increased intracellular or extracellular fluid, which would be reflected in complementary high apparent diffusion coefficients (bulk mean diffusivity) and low FA, or from disorganization of fiber structure, which would be reflected in low FA but with a lack of the inverse FA and diffusivity relationship. To test these competing possibilities, we examined 15 alcoholic men and 31 control men with DTI to quantify diffusivity in the genu and splenium of the corpus callosum and centrum semiovale. In addition to the previously observed FA deficits in all the three brain regions, the alcoholics had abnormally high white matter diffusivity values in the genu and centrum. Further, inverse correlations between FA and diffusivity were significant in the genu (r ¼ À0.52, po0.05) and centrum (r ¼ À0.92, p ¼ 0.0001). Multiple regression analyses examining diffusivity and age as predictors of FA identified diffusivity as a significant unique contributor to FA in both regions. These results suggest that decreased orientational coherence of brain white matter in alcoholism is attributable, at least in part, to the accumulation of intracellular and extracellular fluid in excess of that occurring in aging, and that the differential influence of these fluid compartments can vary across brain regions.

Introduction: Meningitis is one of the most common and serious disorders of central nervous system infection in neonates characterized by inflammation of piaarachnoid membrane with symptoms of lethargy, irritability, vomiting, and seizures. 1 Factors responsible for early onset of meningitis includes obstetric complications, prematurity, prolonged rupture of membranes, maternal infection and chorioamnionitis. Fatality rate associated with this disease can be as high as 20-30 %. 1 The major neuropathological consequence of bacterial neonatal meningitis is cerebral atrophy, manifested by loss of cerebral cortical neuron and loss of myelin in periventricular white matter. The disorder fulminates in evolution but is amenable to therapeutic intervention; early diagnosis of neonatal meningitis followed by appropriate medical management can have a favorable effect on outcome. Till date definitive diagnosis of meningitis is dependent on examination and culture of cerebrospinal fluid (CSF). Although conventional magnetic resonance imaging (MRI) is more sensitive then computerized tomography (CT) to detect inflammatory vasculitis, it is insensitive to subtle changes in tissue microstructure. 3 Diffusion tensor imaging (DTI) characterizes the spatial properties of molecular diffusion that provides insights into whitematter microstructure. The aim of this study was to determine the role of DTI derived metrics in early detection of infection related white matter damage and to compare these measures with the clinical outcome of disease.

Age-dependent changes in the normal cerebral white matter have been reported; however, there is no study on normal cerebellar white matter maturation in developing brain using diffusion tensor imaging (DTI). We performed DTI in 21 children who had normal neurological assessment along with no evidence of any abnormality on imaging. The aim of this study was to compare the agerelated changes in fractional anisotropy (FA) and mean diffusivity (MD) quantified from cerebral white matter (splenium and genu of the corpus callosum and posterior limb of the internal capsule) and cerebellar white matter (middle cerebellar peduncles, superior cerebellar peduncles, and inferior cerebellar peduncles) regions in healthy children ranging in age from birth to 132 months. Loglinear regression model showed best fit to describe the agerelated changes in FA and MD both for cerebral and cerebellar white matter. In cerebral white matter, an initial sharp increase in FA was observed up to the age of 24 months followed by a gradual increase up to 132 months. In cerebellar white matter, sharp increase in FA was observed up to 36 months, which then followed a gradual increase. However, MD showed a sharp decrease in cerebral white matter up to 24 months followed by a more gradual decrease thereafter, while in cerebellar white matter after an initial decrease (6 months), it followed a stable pattern. This study provides normative database of brain white matter development from neonates to childhood. This quantitative information may be useful for assessing brain maturation in patients with developmental delay of the cerebral and cerebellar white matter.

Hyperammonemia and inflammation are major contributing factors in the development of cerebral edema (CE) in acute liver failure (ALF). Aim of this study was to look for the relationship between proinflammatory cytokines with diffusion tensor imaging (DTI) derived metrics and 1 H-MR spectroscopy ( 1 H-MRS) derived Glutamate/Glutamine (Glx). Fourteen patients with ALF and 14 age/sex matched controls were included in this study. All subjects had undergone clinical, biochemical, MR imaging and 1 H-MRS studies. Serum proinflammatory cytokines (IL-6 and TNF-α), blood ammonia level and Glx were computed for independent t-test and Pearson correlation. Serum proinflammatory cytokines, blood ammonia level and brain Glx were significantly increased in ALF patients as compared to controls. Blood ammonia level and Glx showed significant positive correla-tion with proinflammatory cytokines. Spectroscopy voxel derived spherical anisotropy (CS) showed positive correlation with Glx while mean diffusivity (MD) showed negative correlation. Proinflammatory cytokines showed positive correlation with CS and negative correlation with MD in various brain regions including spectroscopy voxel. Significant correlation of Glx, CS and MD with proinflammatory cytokines suggests that both DTI derived metrics and 1 H-MRS measure the synergistic effect of hyperammonemia and proinflammatory cytokines and may be used as non-invasive tools for understanding the pathogenesis of CE in ALF.

This study aimed to demonstrate age-related and gender-related changes in diffusion tensor imaging (DTI) indices of deep grey matter (GM) nuclei of the normal human brain. DTI was performed on 142 subjects (age: 10-52 years). Regions of interest were placed on the caudate nucleus (CN), putamen, globus pallidus, frontal white matter (WM), occipital WM, anterior and posterior limb of internal capsule, genu of the corpus callosum and splenium in all participants. The quadratic regression model was used to describe age-related and gender-related changes in DTI indices for GM and WM. We observed increased fractional anisotropy (FA) values with age up to adulthood in GM, and a rise up to the third decade of life followed by a decrease in FA for WM. We observed higher FA values in males compared to females in CN and all WM regions. Decreased mean diffusivity with age was observed in GM and WM irrespective of gender. This normative data may be valuable in the diagnosis of neurodegenerative diseases.

تصوير برداري پزشكي يك تكنيك غير تهاجمي ميباشد كه باعث توسعه قابل توجه در تشخيص و شناسايي بيماريهاي انسان شده است. در ميان تمامي تكنيكهاي تصوير برداري پزشكي، روش تصويربرداري تشديد مغناطيسي داراي محبوبيت بيشتري است. اين روش، براي سلامت انسان مضر نيست و همچنين توانايي تصوير برداري از جزئيات مغز انسان را با كيفيت بالايي انجام
مغز اطلاعاتي ارزشمند در مورد بافت و قسمتهاي مختلف مغز بدست مي- MR ميدهد. راديولوژيستها با استفاده از تصاوير عدم كنتراست بالاي تصوير و پيچيدگي بالاي يك ،MR آورند. راديولوژيستها و پزشكان در مواردي از جمله نويزي بودن تصاوير ضايعه در درون مغز، ممكن است در تشخيص با مشكل مواجه شوند. همچنين خستگي راديولوژيست و پزشك نيز ميتواند يكي
از دلايل عدم تشخيص صحيح در درمان باشد. بنابراين ميتوان نتيجه گرفت استفاده از يك الگوريتم هوشمند قدرتمند در كنار مغز ميتواند قابليت دقت تشخيص راديولوژيست و پزشك را در شناسايي بيماري مغزي افزايش دهد. با توجه به اين MR تصاوير مغزي استفاده شده MR و استخراج ويژگيهاي محلي جهت طبقهبندي تصاوير Ripplet مورد در اين پاياننامه از تركيب تبديل
ميباشد. روش MR است كه هدف از ارائه روش معرفي شده افزايش معيارهاي دقت، حساسيت و ويژگي براي طبقهبندي تصاوير پيشنهادي با استفاده از نرم افزار متلب پيادهسازي گرديده است. نتايج حاصل از پيادهسازي با دقت ٩٧ % و خطاي كم، طبقه بندي مغزي را انجام داده به طوري كه باعث عملكرد بهتر نسبت به ساير روشها شده است.