Zobrazení tenzorů difuze (diffusion tensor imaging, DT I) je poměrně nová technika vyšetření magnetickou rezonancí, která je v současné době jako jediná schopna zobrazit bližší strukturální detaily bílé hmoty mozku. Sofistikované softwarové zpracování základních dat umožňuje vizualizovat jednotlivé dráhy nebo měřit číselné hodnoty parametrů DTI, které dle dosavadních publikací citlivě reagují na strukturální poškození bílé hmoty. Autoři této práce si kladou za cíl přinést přehled současných aplikací DT I pro zobrazení bílé hmoty mozku. Probírány jsou základní technické aspekty, možnosti praktického využití této metody v běžné klinické praxi a v neposlední řadě i ryze výzkumné aplikace směřující k detekci a kvantifikaci diskrétní ultrastrukturální patologie u různých onemocnění bílé hmoty mozkové.

Diffusion tensor imaging (DTI) is a relatively new magnetic resonance imaging technique that is capable of unique depiction of the structural detail in brain white matter. Its sophisticated software algorithms provide either three-dimensional reconstructions and visualizations of the particular tracts of the white matter or quantifications of various DTI parameters that appear, according to certain studies, to be highly sensitive to structural abnormalities in white matter. The aim of the present paper is to review the current applications of DTI for the depiction of brain white matter. Some basic technical remarks are made and clinical aspects are discussed, as well as purely research applications aimed at the detection and quantification of the subtle ultra-structural pathology of brain white matter.

• MeSH
• Amyotrophic Lateral Sclerosis diagnosis   MeSH
• Central Nervous System physiology   physiopathology   pathology   MeSH
• Diagnostic Techniques, Neurological instrumentation   trends   utilization   MeSH
• Diffusion Magnetic Resonance Imaging methods   instrumentation   utilization   MeSH
• Financing, Organized MeSH
• Humans MeSH
• Brain Neoplasms diagnosis   etiology   MeSH
• Brain Diseases diagnosis   etiology   MeSH
• Nerve Tissue MeSH
• Neural Pathways MeSH
• Image Processing, Computer-Assisted methods   instrumentation   utilization   MeSH
• Preoperative Care methods   utilization   MeSH
• Multiple Sclerosis diagnosis   MeSH
• Schizophrenia diagnosis   MeSH
• Stereotaxic Techniques instrumentation   utilization   MeSH
• Imaging, Three-Dimensional methods   instrumentation   utilization   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Review MeSH

Radiation myelopathy (RM) is a rare complication of spinal cord irradiation. Diagnosis is based on the history of radiotherapy, laboratory tests, and magnetic resonance imaging of the spinal cord. The MRI findings may nevertheless be quite unspecific. In this paper, we describe the findings of diffusion tensor imaging in a case of the delayed form of RM. We observed areas of restricted diffusion within the spinal cord which probably corresponded to the ischemic changes. This would concur with the currently accepted pathogenetic theory concerning RM.

• MeSH
• Diagnosis, Differential MeSH
• Radiotherapy, Conformal adverse effects   MeSH
• Middle Aged MeSH
• Humans MeSH
• Spinal Neoplasms radiotherapy   MeSH
• Spinal Cord Diseases etiology   pathology   MeSH
• Radiation Injuries etiology   pathology   MeSH
• Treatment Outcome MeSH
• Diffusion Tensor Imaging methods   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH

Úvod: V diagnostice idiopatického normotenzního hydrocefalu (iNPH) chybí spolehlivý nástroj. Perspektivu má magnetická rezonance (MR). Jednou z modalit MR je zobrazení difuzních tenzorů (DTI). Cílem bylo porovnat parametry DTI u pacientů před operací a po ní a u zdravých dobrovolníků. Metodika a materiál: Pacientům byla provedena MR mozku před operací a 1 rok po operaci. Dále byli vyšetřeni zdraví dobrovolníci. Parametry DTI (frakční anizotropie; FA; průměrná difuzivita; MD) byly měřeny v předním a zadním raménku capsula interna a v corpus callosum (ALIC, PLIC, CC). Do studie bylo zahrnuto 27 pacientů s iNPH a 24 zdravých dobrovolníků. Výsledky: U iNPH pacientů byla MD vyšší ve všech měřených oblastech než u zdravých dobrovolníků (p < 0,05). FA byla u pacientů vyšší jen v PLIC (p < 0,001). Jeden rok po operaci byl patrný pokles hodnoty FA v PLIC (p < 0,001). V jiných oblastech k poklesu FA či MD nedošlo. Hodnota FA v PLIC ani po operaci nedosáhla hodnot zdravých dobrovolníků (0,63 po operaci vs. 0,58 u kontrol). Závěr: Hodnota FA v PLIC je u pacientů s iNPH signifikantně vyšší než u zdravých. Po operaci klesá. Hodnoty MD byly vyšší v ALIC, PLIC i CC. Po operaci pokles nenastává, což odráží stupeň degenerace bílé hmoty u pacientů s iNPH.

Introduction: Idiopathic normal pressure hydrocephalus (iNPH) is a disease with many unanswered questions. General effort is to find a simple and non-invasive diagnostic tool. Magnetic resonance imaging (MRI) is a topic for intensive research. Diffusion tensor imaging (DTI) is one of the MRI modalities. This examination can detect microstructural changes of the cerebral white matter. The aim of this study was to compare the DTI parameters in iNPH patients before and after a surgery and with healthy volunteers. Material and methods: MRI was performed in patients before surgery and 1 year after. We also examined age-matched healthy volunteers. The DTI parameters (fractional anisotropy; FA and mean diffusivity; MD) were measured in the anterior and posterior limb of the internal capsule and in the corpus callosum (ALIC, PLIC, CC). Acquired data were statistically analysed. We enrolled 27 patients with iNPH and 24 healthy volunteers. Results: MD was higher in all measured regions comparing iNPH and healthy volunteers (p < 0.05). FA was higher in the PLIC only (p < 0.001). Comparing our data before surgery and one year after, we found significant decrease of FA in the PLIC (p < 0.001) but FA in this region did not reached the FA level in the healthy volunteers group (0.63 after the surgery vs. 0.58 in volunteers). No other significant change in FA or MD was noticed. Conclusion: This study proved, that the FA in the PLIC is significantly higher in iNPH patients than in healthy volunteers. After the surgery, FA decreased. MD values were significantly higher in iNPH patients in the ALIC, PLIC and CC with no decrease after the surgery. It reflects degeneration of the white matter in iNPH patients.

• MeSH
• Internal Capsule diagnostic imaging   MeSH
• Corpus Callosum diagnostic imaging   MeSH
• Diffusion Magnetic Resonance Imaging * MeSH
• Intracranial Pressure physiology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Hydrocephalus, Normal Pressure * diagnostic imaging   diagnosis   surgery   MeSH
• Prospective Studies MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Ventriculoperitoneal Shunt MeSH
• Treatment Outcome MeSH
• Diffusion Tensor Imaging * MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH

Cíl: Vyvinout vyšetřovací protokol umožňující zobrazení funkční integrity a mikrostrukturálního postižení periferních nervů (PN) v různých lokalitách pomocí difuzního tenzoru (DTI). Následně implementovat vyšetřovací protokol do klinické praxe. Soubor a metodika: Vyšetřili jsme 15 zdravých dobrovolníků a 15 pacientů na 3T MR přístroji pomocí metody DTI. Snažili jsme se zobrazit brachiální plexus, lumbosakrální plexus a průběh PN na končetinách u zdravých dobrovolníků. U pacientů jsme cílili vyšetření na postižené úseky PN za účelem zobrazit tyto patologie. Výsledky: Podařilo se nám získat validní zobrazení brachiálního i lumbosakrálního plexu a průběhu PN na končetinách pomocí DTI. Setkali jsme se s některými limitacemi metody, zejména pohybovými artefakty, narušujícími kvalitní zobrazení nervových struktur, a problémy s odlišením nervových vláken od vláken svalových. Tyto technické problémy mohou být do určité míry eliminovány využitím adekvátních cívek, optimalizací zobrazovacích protokolů a metodikou následného zpracování dat. Závěr: Přes některé technické limitace práce demonstruje možnost získat validní zobrazení PN v různých lokalitách prostřednictvím metody DTI. DTI představuje doplňkovou neinvazivní zobrazovací techniku poskytující cenné informace využitelné v rozhodovacím diagnostickém a léčebném procesu u nejrůznějších patologií PN. Technologický pokrok a další zdokonalování metod MR v budoucnu pravděpodobně povede k rozšíření a širšímu uplatnění této techniky v klinické praxi.

Aim: Development of an examination protocol for investigation of functional integrity and microstructural damage of peripheral nerves (PN) at different locations using diffusion tensor imaging (DTI). Consequently, we want to implement this protocol into clinical practice. Subjects and methods: We investigated 15 healthy volunteers and 15 patients with a 3T MRI, scanner using the DTI method. We attempted to visualize the brachial plexus, lumbosacral plexus and the course of PN in the limbs of healthy volunteers. In patients, we focused on the examination of damaged parts of the PN to display these pathologies. Results: We managed to obtain a valid visualization of the brachial plexus, lumbosacral plexus and the course of PN in the limbs using DTI. Throughout the study, we encountered some limitations of this method, particularly motion artifacts which interfered with the quality of nerve structure imaging and problems in differentiating nerve fibers from muscle fibers. These technical problems could be reduced to a certain extent using adequate coils, optimizing imaging protocols and data procesing methodology. Conclusion: Despite some technical limitations, this paper demonstrates the possibility of obtaining a valid display of PN in different locations using the DTI method. DTI is an additional non-invasive imaging technique providing valuable information useful in the decision-making diagnostic and therapeutic process for various PN pathologies. Technological advances and further improvements of MRI techniques in the future are likely to result in a wider use of this technique in clinical practice.

• MeSH
• Adult MeSH
• Clinical Studies as Topic MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging * methods   MeSH
• Young Adult MeSH
• Peripheral Nerves * diagnostic imaging   MeSH
• Brachial Plexus diagnostic imaging   MeSH
• Lumbosacral Plexus diagnostic imaging   MeSH
• Diffusion Tensor Imaging * methods   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH

BACKGROUND AND PURPOSE: The primary objective was to compare diffusion tensor imaging (DTI) scalar parameters of peripheral nerves between subjects with type 2 diabetes mellitus (T2DM) and those without diabetes. Secondarily, we aimed to correlate DTI scalar parameters with nerve morphometric properties. METHODS: Median, tibial, and sural nerves were harvested from 34 male cadavers (17 T2DM, 17 nondiabetic). Each nerve was divided into three segments. The initial segment was scanned using 9.4 Tesla MRI system (three-dimensional pulsed-gradient spin-echo sequence). DTI scalars were calculated from region-average diffusion-weighted signals. Second segment was optically cleared, acquired with optical projection tomography (OPT), and analyzed for morphometrical properties. Toluidine-stained sections were prepared from last segment, and axon- and myelin-related properties were evaluated. RESULTS: DTI scalar parameters of median and tibial nerves were comparable between the groups, while sural nerves of T2DM exhibited on average 41% higher mean diffusivity (MD) (p = 0.03), 38% higher radial diffusivity (RD) (p = 0.03), and 27% lower fractional anisotropy (FA) (p = 0.005). Significant differences in toluidine-evaluated parameters of sural nerves were observed between the groups, with a positive correlation between FA with fiber density (p = 0.0001) and with myelin proportion (p < 0.0001) and an inverse correlation between RD and myelin proportion (p = 0.003). OPT-measured morphometric properties did not correlate with DTI scalar parameters. CONCLUSIONS: High-field DTI shows promise as an imaging technique for detecting axonal and myelin-related changes in small sural nerves ex vivo. The reduced fiber density and decreased myelin content, which can be observed in T2DM, likely contribute to observed FA reduction and increased MD/RD.

• MeSH
• Diabetes Mellitus, Type 2 * diagnostic imaging   pathology   MeSH
• Diabetic Neuropathies diagnostic imaging   pathology   MeSH
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Cadaver * MeSH
• Median Nerve diagnostic imaging   pathology   MeSH
• Sural Nerve * diagnostic imaging   pathology   MeSH
• Tibial Nerve diagnostic imaging   pathology   MeSH
• Reproducibility of Results MeSH
• Aged MeSH
• Sensitivity and Specificity MeSH
• Diffusion Tensor Imaging * methods   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH

To meet the need for Parkinson's disease biomarkers and evidence for amount and distribution of pathological changes, MRI diffusion tensor imaging (DTI) has been explored in a number of previous studies. However, conflicting results warrant further investigations. As tissue microstructure, particularly of the grey matter, is heterogeneous, a more precise diffusion model may benefit tissue characterization. The purpose of this study was to analyze the diffusion-based imaging technique restriction spectrum imaging (RSI) and DTI, and their ability to detect microstructural changes within brain regions associated with motor function in Parkinson's disease. Diffusion weighted (DW) MR images of a total of 100 individuals, (46 Parkinson's disease patients and 54 healthy controls) were collected using b-values of 0-4000s/mm2. Output diffusion-based maps were estimated based on the RSI-model combining the full set of DW-images (Cellular Index (CI), Neurite Density (ND)) and DTI-model combining b = 0 and b = 1000 s/mm2 (fractional anisotropy (FA), Axial-, Mean- and Radial diffusivity (AD, MD, RD)). All parametric maps were analyzed in a voxel-wise group analysis, with focus on typical brain regions associated with Parkinson's disease pathology. CI, ND and DTI diffusivity metrics (AD, MD, RD) demonstrated the ability to differentiate between groups, with strongest performance within the thalamus, prone to pathology in Parkinson's disease. Our results indicate that RSI may improve the predictive power of diffusion-based MRI, and provide additional information when combined with the standard diffusivity measurements. In the absence of major atrophy, diffusion techniques may reveal microstructural pathology. Our results suggest that protocols for MRI diffusion imaging may be adapted to more sensitive detection of pathology at different sites of the central nervous system.

• MeSH
• Nerve Degeneration diagnosis   diagnostic imaging   pathology   MeSH
• Diagnostic Imaging * MeSH
• Diffusion Magnetic Resonance Imaging MeSH
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Brain Stem diagnostic imaging   pathology   MeSH
• Parkinson Disease diagnosis   diagnostic imaging   pathology   MeSH
• Gray Matter diagnostic imaging   pathology   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Substantia Nigra diagnostic imaging   pathology   MeSH
• Thalamus diagnostic imaging   pathology   MeSH
• Diffusion Tensor Imaging * MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

A wide range of imaging studies provides growing support for the potential role of diffusion tensor imaging (DTI) in evaluating microstructural white matter integrity in Alzheimer disease (AD) and mild cognitive impairment (MCI). Our review aims to present DTI principles, post-processing and analysis frameworks and to report the results of particular studies. The distribution of AD-related white matter abnormalities is widely discussed in the light of deteriorated connectivity within certain tracts due to secondary white matter degeneration; primary alterations are also assumed to contribute to the pattern. The question whether it is more effective to assess the whole-brain diffusion or to directly concentrate on specific regions remains an interesting issue. Assessing white matter microstructure alterations, as evaluated by group-level differences of tensor-derived parameters, may be a promising neuroimaging tool for differential diagnosis between AD, MCI and other cognitive disorders, as well as being particularly helpful in the interpretation of underlying pathological processes.

• MeSH
• Alzheimer Disease complications   diagnosis   pathology   MeSH
• Diagnosis, Differential MeSH
• Cognitive Dysfunction etiology   MeSH
• Cognition Disorders diagnosis   MeSH
• Leukoencephalopathies diagnosis   MeSH
• Humans MeSH
• Brain pathology   MeSH
• Diffusion Tensor Imaging * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

The aim of this study was to investigate whether white matter changes as measured by diffusion tensor imaging (DTI) can help differentiate shunt-responsive idiopathic normal pressure hydrocephalus (iNPH) patients from patients with other causes of gait disturbances and/or cognitive decline with ventriculomegaly whose clinical symptoms do not improve significantly after cerebrospinal fluid derivation (non-iNPH). Between 2017 and 2022, 85 patients with probable iNPH underwent prospective preoperative magnetic resonance imaging (MRI) and comprehensive clinical workup. Patients with clinical symptoms of iNPH, positive result on lumbar infusion test, and gait improvement after 120-h lumbar drainage were diagnosed with iNPH and underwent shunt-placement surgery. Fractional anisotropy (FA) and mean diffusivity (MD) values for individual regions of interest were extracted from preoperative MRI, using the TBSS pipeline of FSL toolkit. These FA and MD values were then compared to results of clinical workup and established diagnosis of iNPH. An identical MRI protocol was performed on 13 age- and sex-matched healthy volunteers. Statistically significant differences in FA values of several white matter structures were found not only between iNPH patients and healthy controls but also between iNPH and non-iNPH patients. ROI that showed best diagnostic ability when differentiating iNPH among probable iNPH cohort was uncinate fasciculus, with AUC of 0.74 (p < 0.001). DTI methods of white matter analysis using standardised methods of ROI extraction can help in differentiation of iNPH patients not only from healthy patients but also from patients with other causes of gait disturbances with cognitive decline and ventriculomegaly.

• MeSH
• Diffusion Magnetic Resonance Imaging methods   MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Hydrocephalus, Normal Pressure * diagnostic imaging   surgery   MeSH
• Prospective Studies MeSH
• Diffusion Tensor Imaging methods   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

BACKGROUND AND PURPOSE: White matter changes assessed by DTI typically reflect tract functionality. This study aimed to investigate DTI parameter alterations in important regions pre- and postshunt implantation in patients with idiopathic normal pressure hydrocephalus (iNPH), alongside assessing the relationship between DTI parameters and clinical improvement. MATERIALS AND METHODS: Patients with probable iNPH underwent prospective preoperative MRI and comprehensive clinical work-up between 2017-2022. Patients with clinical symptoms of iNPH, positive result on a lumbar infusion test, and/or gait improvement after 120-hour lumbar drainage were diagnosed with iNPH and underwent shunt-placement surgery. Fractional anisotropy and mean diffusivity values for individual regions of interest were extracted from preoperative and postoperative MRI. These values were correlated with the clinical picture of individual patients. RESULTS: A total of 32 patients (73.59 ± 4.59 years) with definite iNPH were analyzed. Preoperative DTI characteristics of internal capsule and corona radiata correlated with the 1-year improvement in the Dutch Gait Scale postoperatively (all P < .036). Cognitive domain improvement after surgery in memory and psychomotor speed correlated with preoperative DTI values of cingulate gyrus (P = .050), uncinate fasciculus (P = .029), superior longitudinal fasciculus (P = .020), or corpus callosum (P < .045). CONCLUSIONS: DTI characteristics of white matter regions reflect clinical improvement after shunt surgery in patients with iNPH. They tend to improve toward physiologic DTI values, thus further accentuating the benefit of shunt surgery in both clinical and radiologic pictures.

• MeSH
• Anisotropy MeSH
• White Matter diagnostic imaging   MeSH
• Middle Aged MeSH
• Humans MeSH
• Hydrocephalus, Normal Pressure * surgery   diagnostic imaging   MeSH
• Prospective Studies MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Cerebrospinal Fluid Shunts * MeSH
• Treatment Outcome MeSH
• Diffusion Tensor Imaging * methods   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Age-related hearing loss (presbycusis) is caused mainly by the hypofunction of the inner ear, but recent findings point also toward a central component of presbycusis. We used MR morphometry and diffusion tensor imaging (DTI) with a 3T MR system with the aim to study the state of the central auditory system in a group of elderly subjects (>65years) with mild presbycusis, in a group of elderly subjects with expressed presbycusis and in young controls. Cortical reconstruction, volumetric segmentation and auditory pathway tractography were performed. Three parameters were evaluated by morphometry: the volume of the gray matter, the surface area of the gyrus and the thickness of the cortex. In all experimental groups the surface area and gray matter volume were larger on the left side in Heschl's gyrus and planum temporale and slightly larger in the gyrus frontalis superior, whereas they were larger on the right side in the primary visual cortex. Almost all of the measured parameters were significantly smaller in the elderly subjects in Heschl's gyrus, planum temporale and gyrus frontalis superior. Aging did not change the side asymmetry (laterality) of the gyri. In the central part of the auditory pathway above the inferior colliculus, a trend toward an effect of aging was present in the axial vector of the diffusion (L1) variable of DTI, with increased values observed in elderly subjects. A trend toward a decrease of L1 on the left side, which was more pronounced in the elderly groups, was observed. The effect of hearing loss was present in subjects with expressed presbycusis as a trend toward an increase of the radial vectors (L2L3) in the white matter under Heschl's gyrus. These results suggest that in addition to peripheral changes, changes in the central part of the auditory system in elderly subjects are also present; however, the extent of hearing loss does not play a significant role in the central changes.

• MeSH
• Auditory Diseases, Central pathology   MeSH
• Adult MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Young Adult MeSH
• Nerve Fibers, Myelinated pathology   MeSH
• Presbycusis pathology   physiopathology   MeSH
• Aged MeSH
• Auditory Pathways pathology   MeSH
• Auditory Cortex pathology   MeSH
• Aging pathology   physiology   MeSH
• Diffusion Tensor Imaging MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH