Interferon-free therapy as the cause of white matter tracts and cerebral perfusion recovery in patients with chronic hepatitis C.

The purpose of this study was to assess cerebral microstructural and perfusion changes in patients with chronic hepatitis C virus (HCV) infection before and after interferon-free therapy, using advanced magnetic resonance (MR) techniques. Eleven HCV-positive patients underwent diffusion tensor imaging (DTI) and perfusion-weighted imaging (PWI) using a 1.5T MR unit, before and 24 weeks after completion of interferon-free therapy. DTI fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained from 14 white matter tracts. PWI values of relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) were assessed from 8 areas, including basal ganglia, and cortical and white matter locations. In HCV-positive patients therapy with ombitasvir, paritaprevir boosted with ritonavir and dasabuvir, with or without ribavirin, was scheduled. Cognitive tests were used to assess cognitive function. We found increased FA values after interferon-free therapy compared to values obtained before treatment in HCV patients in almost all white matter tracts. We also observed elevated rCBV values in basal ganglia after therapy. There were significant correlations between improvement in the score of cognitive tests and increased FA values in both inferior fronto-occipital fascicles and left posterior cingulum after treatment. Liver fibrosis regression in elastography, APRI and improvement in cognitive tests were observed. This is the first report of interferon-free therapy as the cause of white matter tracts recovery as well as cerebral perfusion improvement in HCV-infected patients, indicating better functioning of frontal lobes after interferon-free treatment.

Magnetic resonance imaging of liver tumors using gadoxetic acid (Gd-EOB-DTPA) - pilot study.

BACKGROUND: Magnetic resonance imaging using gadoxetic acid, a hepatocyte-specific contrast agent, is one of the most useful MRI techniques used to diagnose liver tumours in humans. During the hepato-biliary phase, there is uptake of gadoxetic acid by normal hepatocytes, leading to hepatic parenchymal enhancement. This feature is used in human medicine to diagnose hepatic parenchymal metastatic disease, to differentiate primary liver tumours, to diagnose liver cirrhosis and focal nodular hyperplasia. This study presents the preliminary results of magnetic resonance imaging of focal lesions localised in the liver parenchyma in dogs following the administration of gadoxetic acid. RESULTS: The lesion enhancement ratio (ERlesion) in the tumour metastasis was 0.05; the liver enhancement ratio (ERliver) - 0.49 and the post-contrast lesion-to-liver contrast ratio (CR) was 0.17. In dogs with hepatocellular hyperplasia, these values were 0.54; 0.51; and 1.18, respectively. In two dogs with a hepatic adenoma, the ERlesion was 0.26 and 0.17, respectively; the ERliver was 0.47 and 0.47, respectively and the CR was 0.33 and 0.31, respectively. In the dog with a neuroendocrine tumour, the ERlesion was 0.03; the ERliver amounted to 0.58 and the CR was 0.35. In the case of a hepatocellular carcinoma, these coefficients were 0.2, 0.6 and 0.3, respectively. CONCLUSION: Based on the results, it may be assumed that the MR images of the proliferative hepatic parenchymal lesions in dogs using gadoxetic acid are similar to those obtained in humans. This suggests that the contrast enhancement patterns used in human medicine may be useful in differentiating hepatic parenchymal lesions in dogs.

Imaging of cerebrospinal fluid flow: fundamentals, techniques, and clinical applications of phase-contrast magnetic resonance imaging.

Cerebrospinal fluid (CSF) is a dynamic compartment of the brain, constantly circulating through the ventricles and subarachnoid space. In recent years knowledge about CSF has expended due to numerous applications of phase-contrast magnetic resonance imaging (PC-MRI) in CSF flow evaluation, leading to the revision of former theories and new concepts about pathophysiology of CSF disorders, which are caused either by alterations in CSF production, absorption, or its hydrodynamics. Although alternative non-invasive techniques have emerged in recent years, PC-MRI is still a fundamental sequence that provides both qualitative and quantitative CSF assessment. PC-MRI is widely used to evaluate CSF hydrodynamics in normal pressure hydrocephalus (NPH), Chiari type I malformations (CMI), syringomyelia, and after neurosurgical procedures. In NPH precisely performed PC-MRI provides reliable clinical information useful for differential diagnosis and selection of patients benefiting from surgical operation. Patients with CMI show abnormalities in CSF dynamics within the subarachnoid space, which are pronounced even further if syringomyelia coexists. Another indication for PC-MRI may be assessment of post-surgical CSF flow normalisation. The aim of this review is to highlight the significance of CSF as a multifunctional entity, to outline both the physical and technical background of PC-MRI, and to state current applications of this technique, not only in the diagnosis of central nervous system disorders, but also in the further clinical monitoring and prognosis after treatment.

Quantitative magnetic resonance assessment of brain atrophy related to selected aspects of disability in patients with multiple sclerosis: preliminary results.

PURPOSE: The aim of this volumetric study was to evaluate the relationship between brain atrophy quantification in multiple sclerosis (MS) patients and the progression of disability measured by neurological standardised tests. MATERIAL AND METHODS: Seventeen patients (mean age 40.89 years) with clinically definite MS and 24 control subjects (mean age 38.45 years) were enrolled in the study. Brain examinations were performed on a 1.5T MR scanner. Automatic brain segmentation was done using FreeSurfer. Neurological disability was assessed in all patients in baseline and after a median follow-up of two years, using EDSS score evaluation. RESULTS: In MS patients we found significantly (p < 0.05) higher atrophy rates in many brain areas compared with the control group. The white matter did not show any significant rate of volume loss in MS patients compared to healthy controls. Significant changes were found only in grey matter volume in MS subjects. At the follow-up evaluation after two years MS patients with deterioration in disability revealed significantly decreased cerebral volume in 14 grey matter areas at baseline magnetic resonance imaging (MRI) compared to MS subjects without disability progression. CONCLUSIONS: Grey matter atrophy is associated with the degree of disability in MS patients. Our results suggest that morphometric measurements of brain volume could be a promising non-invasive biomarker in assessing the volumetric changes in MS patients as related to disability progression in the course of the disease.

The evaluation of the aortic annulus displacement during cardiac cycle using magnetic resonance imaging.

BACKGROUND: The stress in the ascending aorta results from many biomechanical factors including the geometry of the vessel and its maximum dimensions, arterial blood pressure and longitudinal systolic stretching due to heart motion. The stretching of the ascending aorta resulting from the longitudinal displacement of the aortic annulus during the heart cycle has not been examined in the general population so far. The aim of the study is to evaluate this parameter using cardiovascular magnetic resonance (CMR) imaging in the general population in all age groups. METHODS: The cardiac magnetic resonance images of 73 patients were evaluated. The maximum distance to which the ventriculo-aortic junction was pulled by the contracting heart (LDAA - longitudinal displacement of the aortic annulus) was measured in the cine coronal sequences. Moreover, the maximum dimensions of the aortic root and the ascending aorta were assessed. RESULTS: The LDAA value was on average 11.6 ± 2.9 mm (range: 3-19 mm; 95% CI: 10.9-12.3 mm) and did not differ between males and females (11.8 ± 2.9 mm vs. 11.2 ± 2.9 mm, p = .408). The diameter of the ascending aorta was 32 ± 6.3 mm (range: 20-57 mm). The maximal dimension of the aortic root was 35 ± 5.1 mm (range: 18-42 mm). There was a statistically significant negative correlation between the LDAA and the age of patients (r = -.38, p = .001). There was no significant correlation between the LDAA and aortic root dimension (r = .1, p = .409) and between the LDAA and diameter of the ascending aorta (r = .16, p = .170). CONCLUSIONS: Human aortic root and ascending aorta are significantly stretched during systole and the distance to which the aorta is stretched decreases with age. The measurement of the longitudinal displacement of the aortic annulus using the CMR is feasible and reproducible.

Alexander disease in a dog: case presentation of electrodiagnostic, magnetic resonance imaging and histopathologic findings with review of literature.

BACKGROUND: Alexander disease is a rare neurodegenerative disorder that has not often been described in dogs. None of the existing descriptions include electrodiagnostic or magnetic resonance imaging workup. This is the first presentation of the results of an electrodiagnostic evaluation including electromyography, motor nerve conduction velocity, F-wave, the brainstem auditory evoked response and magnetic resonance imaging of a dog with Alexander disease. CASE PRESENTATION: A six month old male entire Bernese mountain dog was presented with central nervous system symptoms of generalized tremor, general stiffness, decreased proprioceptive positioning, a reduced menace response, decreased physiological nystagmus, myotonic spasms and increased spinal reflexes which progressed to lateral recumbency. The electromyography revealed normal muscle activity and a decreased motor nerve conduction velocity, temporal dispersion of the compound muscle action potential, prolonged F-wave minimal latency, lowered F-ratio, decreased latency, and lowered amplitude of the brainstem auditory evoked potentials. The magnetic resonance imaging examination revealed ventriculomegaly and linear hyperintensity on the border of the cortical grey and white matter. The histopathological examination confirmed the presence of diffuse degenerative changes of the white matter throughout the neuraxis. A proliferation of abnormal astrocytes was found at the border between the white matter and cortex. There was also a massive accumulation of eosinophilic Rosenthal fibers as well as diffuse proliferation of abnormally large astrocytes and unaffected neurons. CONCLUSION: This is the first histopathologically confirmed case of Alexander disease in a dog with a full neurological workup. The results of the electrodiagnostic and magnetic resonance imaging examinations allow for a high-probability antemortem diagnosis of this neurodegenerative disorder in dogs.

Usefulness of diffusion tensor MR imaging in the assessment of intramedullary changes of the cervical spinal cord in different stages of degenerative spine disease.

PURPOSE: The aim of this study was to evaluate the usefulness of diffusion tensor imaging (DTI) in the detection of cervical spinal cord integrity alterations in different stages of degenerative spine disease, as well as to compare DTI parameters with selected cervical spinal stenosis measurements. METHODS: One hundred and thirty-two symptomatic patients (mean age 53.58 years) with different stages of cervical spondylosis and twenty-five control subjects (mean age 45.78 years) were enrolled in the study. DTI was performed with a 1.5 T MR scanner. Three hundred and forty-nine spine segments from C2/C3 to C5/C6 were evaluated and divided into five groups according to the degree of spinal cord compression. The values of fractional anisotropy (FA) and apparent diffusion coefficient at each level were calculated and their correlations with the degree of stenosis were analyzed. RESULTS: FA values differed significantly (p < 0.0001) at all levels between the control group and patients with cervical degenerative disease, including subjects without spinal cord compression visible on plain MR images. A significant (p < 0.01) positive correlation between the mean FA values and anteroposterior diameter of the spinal canal as well as space available for the spinal cord index was demonstrated at all investigated levels. CONCLUSION: DTI is capable of revealing impairment of the cervical spinal cord microstructure at the very early stage of degenerative spine disease, even prior to spinal cord compression visible on plain MR. Anteroposterior spinal canal diameter as well as space available for the cord index is well related to spinal cord tissue integrity defined by DTI.

Central nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy-MRS and DTI study.

Objective: The current research aimed to analyze the alterations within the motor cortex and pyramidal pathways and their association with the degree of damage within the peripheral nerve fibers in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). To achieve that goal, we investigated the microstructural changes within the pyramidal white matter tracts using diffusion tensor imaging (DTI) parameters, evaluated metabolic alterations in both precentral gyri using magnetic resonance spectroscopy (MRS) ratios, and correlated them with the neurographic findings in patients with CIDP. Methods: The spectroscopic ratios of NAA/Cr, Cho/Cr, and mI/Cr from both precentral gyri and the values of fractional anisotropy (FA), axial diffusivity (AD), and mean diffusivity (MD) from both of the corticospinal tracts were correlated with the results of neurological and neurographic findings. The comparison of DTI parameters between the patients and controls was performed using Student's t-test or the Mann-Whitney U test. Due to the lack of normal distribution of most variables, Spearman's Rho rank coefficient was used to test all correlations. All analyses were performed at a significant level of alpha = 0.05 using STATISTICA 13.3. Results: Compared to the control group (CG), the patient group showed significantly lower ratios of NAA/Cr (1.66 ± 0.11 vs. 1.61 ± 0.15; p = 0.022), higher ratios of ml/Cr in the right precentral gyrus (0.57 ± 0.15 vs. 0.61 ± 0.08; p = 0.005), and higher levels of Cho/Cr within the left precentral gyrus (0.83 ± 0.09 vs. 0.88 ± 0.14, p = 0.012). The DTI parameters of MD from the right CST and AD from the right and left CSTs showed a strong positive correlation (0.52-0.53) with the sural sensory nerve action potential (SNAP) latency of the right sural nerve. There were no other significant correlations between other DTI and MRS parameters and neurographic results. Significance: In our study, significant metabolic alterations were found in the precentral gyri in patients with CIDP without clinical symptoms of central nervous system involvement. The revealed changes reflected neuronal loss or dysfunction, myelin degradation, and increased gliosis. Our results suggest coexisting CNS damage in these patients and may provide a new insight into the still unknown pathomechanism of CIDP.

Evaluation of the Value of Perfusion-Weighted Magnetic Resonance Imaging in the Differential Diagnosis of Sellar and Parasellar Tumors.

The purpose of this study was to assess the value of perfusion-weighted imaging (PWI) in the differential diagnosis of sellar and parasellar tumors, as an additional sequence in the magnetic resonance imaging (MRI) protocol. Analysis was based on a substantial group of subjects and included 124 brain and pituitary MRI examinations with a dynamic susceptibility contrast (DSC) PWI sequence. The following perfusion parameters were determined for the tumors: relative cerebral blood volume (rCBV), relative peak height (rPH) and relative percentage of signal intensity recovery (rPSR). To ensure greater repeatability, each of the aforementioned parameters was calculated as: arithmetic mean of the values of the whole tumor, arithmetic mean of the maximum values on each axial slice within the tumor and maximum values derived from the whole tumor. In our study, we established that meningiomas compared to both non-functional and hormone-secreting pituitary adenomas (pituitary neuroendocrine tumors-PitNET) had significantly higher values of rCBV with cut-off points set at 3.45 and 3.54, respectively (mean rCBV). Additionally, meningiomas presented significantly higher maximum and mean maximum rPH values compared to adenomas. DSC PWI imaging adds significant value to conventional MRI examinations and can be helpful in differentiating equivocal pituitary tumors.

Novel Volumetric and Surface-Based Magnetic Resonance Indices of the Aging Brain - Does Male and Female Brain Age in the Same Way?

Introduction: Novel post-processing methods allow not only for assessment of brain volumetry or cortical thickness based on magnetic resonance imaging (MRI) but also for more detailed analysis of cortical shape and complexity using parameters such as sulcal depth, gyrification index, or fractal dimension. The aim of this study was to analyze changes in brain volumetry and other cortical indices during aging in men and women. Material and Methods: Material consisted of 697 healthy volunteers (aged 38-80 years; M/F, 264/443) who underwent brain MRI using a 1.5-T scanner. Voxel-based volumetry of total gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) was performed followed by assessment of cortical parameters [cortical thickness (CT), sulcal depth (SD), gyrification index (GI), and fractal dimension (FD)] in 150 atlas locations using surface-based morphometry with a region-based approach. All parameters were compared among seven age groups (grouped every 5 years) separately for men and women. Additionally, percentile curves for men and women were provided for total volumes of GM, WM, and CSF. Results: In men and women, a decrease in GM and WM volumes and an increase in CSF volume seem to progress slowly since the age of 45. In men, significant GM and WM loss as well as CSF increase start above 55 years of age, while in women, significant GM loss starts above 50 and significant WM loss as well as CSF increase above 60. CT was found to significantly decrease with aging in 39% of locations in women and in 36% of locations in men, SD was found to increase in 13.5% of locations in women and in 1.3% of locations in men, GI was decreased in 3.4% of locations in women and in 2.0% of locations in men, and FD was changed in 2.7% of locations in women compared to 2.0% in men. Conclusions: Male and female brains start aging at the similar age of 45. Compared to men, in women, the cortex is affected earlier and in the more complex pattern regarding not only cortical loss but also other alterations within the cortical shape, with relatively longer sparing of WM volume.

Resting-State Functional Connectivity of the Ageing Female Brain-Differences Between Young and Elderly Female Adults on Multislice Short TR rs-fMRI.

Introduction: Age-related brain changes are one of the most important world health problems due to the rising lifespan and size of the elderly populations. The aim of the study was to assess the effect of ageing in women on coordinated brain activity between eight resting-state networks. Material and Methods: The study group comprised 60 healthy female volunteers who were divided into two age groups: younger women (aged 20-30 n = 30) and older women (aged 55-80 n = 30). Resting-state data were collected during a 15 min scan in the eyes-closed condition using a 3T MR scanner. Data were preprocessed and analysed using the CONN toolbox version 19.c. The large-scale network analysis included a priori selected regions of interest of the default mode, the sensorimotor, the visual, the salience, the dorsal attention, the fronto-parietal, the language, and the cerebellar network. Results: Within the visual, the default mode, the salience, and the sensorimotor network, the intra-network resting-state functional connectivity (RSFC) was significantly higher with increasing age. There was also a significant increase in the inter-network RSFC in older females compared to young females found in the following networks: sensorimotor lateral and salience, salience and language, salience and fronto-parietal, cerebellar anterior and default mode, cerebellar posterior and default mode, visual and sensorimotor lateral, visual and sensorimotor, visual lateral and default mode, language and cerebellar anterior, language and cerebellar posterior, fronto-parietal and cerebellar anterior, dorsal attention and sensorimotor, dorsal attention and default mode, sensorimotor superior, and salience. Compared to young females, elderly women presented bilaterally significantly lower inter-network RSFC of the salience supramarginal gyrus and cerebellar posterior, sensorimotor lateral, and cerebellar anterior network, and sensorimotor lateral and cerebellar posterior as well as sensorimotor superior and cerebellar posterior network. Conclusion: Increased RSFC between some brain networks including the visual, the default mode, the salience, the sensorimotor, the language, the fronto-parietal, the dorsal attention, and the cerebellar networks in elderly females may function as a compensation mechanism during the ageing process of the brain. To the best of our knowledge, this study is the first to report the importance of increase of cerebellar networks RSFC during healthy female ageing.

The Impact of Common Epidemiological Factors on Gray and White Matter Volumes in Magnetic Resonance Imaging-Is Prevention of Brain Degeneration Possible?

Introduction: The aim of the study was to evaluate the impact of multiple risk factors (age, diabetes, hypertension, hyperlipidemia, BMI, smoking, alcohol) on the gray and white matter volumes as well as on the burden of white matter hyperintensities (WMH). Material and Methods: The study group consisted of 554 subjects (age range: 50-69 yrs, F/M: 367/187) recruited from the larger cohort of the Polish fraction of the Prospective Urban Rural Epidemiological (PURE) study. The participants answered questionnaires about their lifestyle, underwent physical and psychological examination (MoCA test), laboratory blood tests followed by brain MRI. Volumetric measurements of the total gray matter (GMvol), total white matter (WMvol) and WHM (WMHvol) normalized to the total intracranial volume were performed using the Computational Anatomy Toolbox 12 (CAT12) and Statistical Parametric Maps 12 (SPM12) based on 3D T1-weighted sequence. The influence of risk factors was assessed using multiple regression analysis before and after correction for multiple comparisons. Results: Older age was associated with lower GMvol and WMvol, and higher WMHvol (p < 0.001). Smaller GMvol volume was associated with higher WMHvol (p < 0.001). Higher WMHvol was associated with hypertension (p = 0.01) and less significantly with hyperlipidemia (only before correction p = 0.03). Diabetes, abnormal BMI, smoking and alcohol intake did not have any significant impact on GMvol, WMvol or WMHvol (p > 0.05). MoCA score was not influenced by any of the factors. Conclusions: Gray matter loss is strongly associated with the accumulation of WMH which seems to be potentially preventable by maintaining normal blood pressure and cholesterol levels.

Analysis of the brain proton magnetic resonance spectroscopy - differences between normal grey and white matter.

BACKGROUND: The proton magnetic resonance spectroscopy (HMRS) is a non-invasive diagnostic method that allows for an assessment of the metabolite concentration in tissues. The sources of the strongest resonance signals within the brain are N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myoinositol (mI) and water. The aim of our study was to analyse the ratios of metabolite signals within the brain in HMRS in the healthy population, to define the differences between the grey and white matter spectra. MATERIAL/METHODS: We studied prospectively 90 subjects aged from 8 to 80 years (mean 43.3 years, SD=17.9), without neurological symptoms or abnormalities in magnetic resonance imaging. In all patients, brain HMRS with Signa HDx 1.5 T MR unit (GE Healthcare) was performed with PRESS sequence, using a single voxel method, at TE of 35 ms and TR of 1500 ms. Spectroscopic evaluation involved voxels placed in the white matter of parietal lobe (PWM) and the grey matter of posterior cingulate gyrus (PGM). On the basis of the intensity of NAA, Cr, Cho, mI and water signals, the proportions of these signals were calculated, as well as the ratio of the analyzed metabolite signal to the sum of signals of NAA, Cho, Cr and mI (%Met) in the PGM and PWM voxels. We compared the proportions in the same patients in PGM and PWM voxels. RESULTS: There has been a statistically significant difference between the proportions of a majority of the metabolite ratios evaluated in PGM and PWM, indicating the higher concentration of NAA, Cr and mI in grey matter, and higher concentration of Cho in white matter. CONCLUSIONS: HMRS spectra of the brain grey and white matter differ significantly. The concentrations of NAA, Cr and mI are higher in grey matter, while of choline - in the white matter.

Interictal Single-Voxel Proton Magnetic Resonance Spectroscopy of the Temporal Lobe in Dogs With Idiopathic Epilepsy.

Proton magnetic resonance spectroscopy (H1-MRS) could provide insight into the metabolic pathophysiology of the temporal lobe of canine brain after seizure. Currently, there is no evidence-based data available on MRS of temporal lobe in dogs with idiopathic epilepsy (IE). The aim of this prospective, cross-sectional study was to evaluate the interictal metabolic activity of the temporal lobe in IE dogs compared to a control group with the use of H1-MRS. Ten healthy dogs and 27 client-owned dogs with IE underwent 1.5-Tesla magnetic resonance imaging (MRI) and single-voxel H1-MRS. The MRS studies were acquired as spin echoes with a repetition time (TR) of 2,000 ms and an echo time (TE) of 144 ms. A cubic voxel (10 ×10 ×10 mm) was positioned bilaterally into the region of the left and right temporal lobe, including a middle part of the hippocampus and the amygdala. The N-acetylaspartate (NAA)-to-creatine (NAA/Cr), NAA-to-choline (NAA/Cho), choline-to-creatine (Cho/Cr), and choline-to-NAA (Cho/NAA) ratios were determined in both hemispheres and compared to controls. No significant differences in all metabolite ratios between epileptic dogs and the control group could be found. A time-dependent decrease in the NAA/Cho ratio as well as an increase in the Cho/NAA ratio was found with proximity in time to the last seizure. We found no correlation between metabolite ratios and age or sex in this animal group. Time span from the last seizure to the acquisition of MRS significantly correlated with NAA/Cho and Cho/NAA ratio. We conclude that without a time relation, metabolite ratios in dogs with IE do not differ from those of the control group.

Diffusion tensor imaging of normal-appearing cervical spinal cords in patients with multiple sclerosis: Correlations with clinical evaluation and cerebral diffusion tensor imaging changes. Preliminary experience.

BACKGROUND: Several studies have identified changes in the spinal cord DTI measurements in patients with multiple sclerosis (MS). However, correlations between changes in DTI parameters in normal appearing cervical spine and neurological findings have not been clearly established. OBJECTIVES: To determine whether diffusion tensor imaging (DTI) measurements such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC) are sufficiently sensitive in detecting microstructure alterations in normal-appearing spinal cords in patients with MS and whether they reflect these patients' clinical disability. MATERIAL AND METHODS: Fifteen patients diagnosed with relapsing-remitting MS (RRMS) with normal-appearing cervical spinal cords on plain MRI and 11 asymptomatic volunteers were enrolled in the study. Overall, 75 cervical spinal segments were analyzed. The regions of interest were drawn from the entire spinal cord cross-section and in the normal-appearing white matter tracts: the superior and inferior cerebellar peduncles and the posterior limbs of the internal capsules. Neurological deficit and the level of disability were evaluated using the Expanded Disability Status Scale (EDSS), the timed 25-foot walk test (T25FW) and the 9-hole peg test (9HPT) for manual dexterity. RESULTS: A significant difference (p < 0.05) in FA values between patients with MS and the control group was found at levels C2 (p = 0.047) and C3 (p = 0.023). No significant changes in ADC values were found. There was correlation between FA and ADC values in selected white matter tracts and at particular spinal cord levels. We also observed significant correlations between diffusion tensor imaging parameters and manual dexterity. CONCLUSIONS: Our preliminary results may suggest that the spinal cord's structural loss is the dominant factor in the inflammatory/demyelinating component in patients with MS. Diffusion tensor imaging changes in the spinal cord correlate with brain DTI changes. Manual functioning seems to be more affected than walking.

MRI Features of the Vomeronasal Organ in Dogs (Canis Familiaris).

According to current knowledge, the vomeronasal organ (VNO, Jacobson's organ) is the structure responsible for semiochemical signal detection. In dogs and other mammals, it is located close to the vomer and palatine processes of the incisive and maxillary bones. Although there are reports describing the anatomy and histology of this structure, there are limited available reports assessing this organ in live individuals and no direct visualization reports in dogs. The aim of this study was 2-fold: (1) preparation and optimization of a protocol for magnetic resonance imaging (MRI) examination of the VNO in a cadaver study with precise visualization and localization, and (2) characterization of the physiological VNO image features in MRI of live dogs. The first part of the study was performed on 10 beagle cadavers, the second on 8 live beagle dogs. For the VNO visualization, a 1.5T MRI (Philips® Ingenia) scanner and 20-channel digital head-neck spine coil were used (Philips®, Holland). The cadaver study allowed confirmation of the organ's location by the topical application of an MRI contrast agent (gadolinium) via the external entrance of the VNO canal. Accurate delineation of the VNO was obtained using a high resolution submillimeter three-dimensional T1-fast field echo (FFE) 3D sequence. Imaging of the VNO in 8 living dogs allowed the description of the morphological MRI features and direct evaluation of its shape and size. The results obtained demonstrate the ability to visualize the VNO in vivo and to evaluate its structure in dogs.

The role of MR volumetry in brain atrophy assessment in multiple sclerosis: A review of the literature.

We review the current role of magnetic resonance (MR) volumetry as a meaningful indicator of neurodegeneration and clinical disease progression in multiple sclerosis (MS) patients. Based on a review of the current literature we summarize the mechanisms that contribute to brain atrophy. We present the newest magnetic resonance imaging (MRI)-based methods used in atrophy quantification. We also analyze important biological factors which can influence the accuracy of brain atrophy evaluation. Evidence shows that measures of brain volume (BV) have the potential to be an important determinant of disease progression to a greater extent than conventional lesion assessment. Finally, scientific reports concerning limitations of MRI-based volumetry that affect its implementation into routine clinical practice are also reviewed. The technical challenges that need to be overcome include creating a standardized protocol for image acquisition - a fully automated, accurate and reproducible method that allows comparison in either single-center or multicenter settings. In the near future, quantitative MR research will probably be the basic method used in neurology to monitor the rate of atrophic processes and clinical deterioration in MS patients, and to evaluate the results of treatment.

The Brain Anatomy of the Brown Bear (Carnivora, Ursus arctos L., 1758) Compared to That of Other Carnivorans: A Cross-Sectional Study Using MRI.

In this study, we aimed to provide a neuroanatomy atlas derived from cross-sectional and magnetic resonance imaging (MRI) of the encephalon of the brown bear (Ursus arctos). A postmortem brain analysis using magnetic resonance imaging (MRI - 1,5T; a high-resolution submillimeter three-dimensional T1-3D FFE) and cross-sectional macroscopic anatomy methods revealed major embryological and anatomical subdivisions of the encephalon, including the ventricular system. Most of the internal structures were comparably identifiable in both methods. The tractus olfactorius medialis, corpus subthalamicum, brachium colliculi rostralis, fasciculus longitudinalis medialis, nuclei vestibulares, velum medullare rostrale, nucleus fastigii, fasciculi cuneatus et gracilis were identified entirely by cross-sectional macroscopic analysis. However, the glandula pinealis, lemniscus lateralis and nuclei rhaphe were visualized only with MRI. Gross neuroanatomic analysis provided information about sulci and gyri of the cerebral hemispheres, components of the vermis and cerebellar hemispheres, and relative size and morphology of constituents of the rhinencephalon and cerebellum constituents. Similarities and discrepancies in identification of structures provided by both methods, as well as hallmarks of the structures facilitating identification using these methods are discussed. Finally, we compare the brown bear encephalon with other carnivores and discuss most of the identified structures compared to those of the domestic dog, the domestic cat, Ursidae and Mustelidae families and Pinnipedia clade.

Evaluation of brain volume alterations in HCV-infected patients after interferon-free therapy: A pilot study.

The study was performed to evaluate cerebral volume changes in HCV-infected subjects before and after interferon-free therapy with direct-acting antiviral agents (DAA). We aimed also to estimate the impact of successful DAA therapy on the neuropsychological state of patients. Eleven HCV genotype 1 (GT1) patients treated with ombitasvir/paritaprevir (boosted with ritonavir) and dasabuvir, with or without ribavirin underwent brain magnetic resonance (MR) before and 24 weeks after completion of therapy. All patients achieved sustained viral response. Precise automatic parcellation was made using the fully-available software FreeSurfer 6.0. Statistically significant volume deceleration six months after treatment was found in the subcallosal cingulate gyrus, transverse frontopolar gyri and sulci, anterior segment of the circular sulcus of the insula and horizontal ramus of the anterior segment of the lateral sulcus. After DAA therapy we found statistically significant improvement in the performance of all three tasks of the Rey Complex Figure Test that permits the evaluation of different functions (attention, planning, working,memory). Additionally, significant amelioration in Percentage Conceptual Level Responses in The Wisconsin Card Sorting Test (a neurocognitive test for assessing intellectual functioning) was also discovered. Successful interferon-free therapy may lead to transient cerebral atrophy, probably by reducing neuroinflammation and oedema. This is the first pilot study of the alterations in brain volume after successful interferon-free therapy in chronic HCV patients. Longitudinal follow-up study is needed to observe further effects of therapy on cerebral structures volume changes.

Visual and brainstem auditory evoked potentials in HCV-infected patients before and after interferon-free therapy - A pilot study.

INTRODUCTION: The aim of this study was to investigate brain bioelectrical activity disturbances in HCV-positive patients before and 24 weeks after interferon-free therapy (DAA), using visual (VEP) and brainstem (BAEP) evoked potentials and advanced magnetic resonance techniques. MATERIALS AND METHODS: 11 HCV-infected patients (6 women, 5 men, mean age 51 years old) and 30 healthy controls, sex and age-matched, were studied. Clinical neurological examinations, VEP, BAEP, diffusion tensor imaging (DTI) and perfusion weighted imaging (PWI) were performed. RESULTS: 11 patients achieved a sustained viral response, and liver fibrosis regression in APRI and in elastography were observed. The mean P100 latency was significantly shorter in HCV-patients after therapy compared to the values before treatment (p<0.05). The mean wave BAEP V latency and I-V interpeak latency were significantly longer in the HCV-infected patients before therapy compared to HCV-patients after therapy. CONCLUSIONS: This study confirms that treatment with DAA in patients with chronic HCV infection positively affects the bioelectrical activity of the brain. An increase in the amplitude of EP after treatment indicates an improvement in the activity of the cerebral cortex. EP examination may be a useful method of assessing the function of the nervous system before and after antiviral treatment.