Loss of inhibition in sensorimotor networks in focal hand dystonia.

Objective: To investigate GABA-ergic receptor density and associated brain functional and grey matter changes in focal hand dystonia (FHD).

Methods: 18 patients with FHD of the right hand and 18 age and gender matched healthy volunteers (HV) participated in this study. We measured the density of GABA-A receptors using [C] Flumazenil and perfusion using [O] HO.

The effect of daclizumab on brain atrophy in relapsing-remitting multiple sclerosis.

Daclizumab is a monoclonal antibody that reduces inflammation in multiple sclerosis (MS). Through a retrospective analysis, our objective was to determine whether daclizumab treatment reduces the rate of brain structure atrophy in comparison to a mixture of other disease-modifying therapies (mainly different interferon β preparations). We analyzed MRI examinations (1332 scans from 70 MS cases) obtained between 2000 and 2011 in a single center and processed with an automated brain segmentation method.

Anatomical correlates of blepharospasm.

Background: Focal dystonia is a neurological disorder characterized by unwanted muscle spasms. Blepharospasm is a focal dystonia producing an involuntary closure of the eyelid. Its etiology is unknown.

A magnetization transfer imaging study of corpus callosum myelination in young children with autism.

Background: Several lines of evidence suggest that autism may be associated with abnormalities in white matter development. However, inconsistencies remain in the literature regarding the nature and extent of these abnormalities, partly because of the limited types of measurements that have been used. Here, we used magnetization transfer imaging to provide insight into the myelination of the corpus callosum in children with autism.

Evidence of left inferior frontal-premotor structural and functional connectivity deficits in adults who stutter.

The neurophysiological basis for stuttering may involve deficits that affect dynamic interactions among neural structures supporting fluid speech processing. Here, we examined functional and structural connectivity within corticocortical and thalamocortical loops in adults who stutter. For functional connectivity, we placed seeds in the left and right inferior frontal Brodmann area 44 (BA44) and in the ventral lateral nucleus (VLN) of the thalamus.

Similarities in speech and white matter characteristics in idiopathic developmental stuttering and adult-onset stuttering.

Adult-onset stuttering (AS) typically occurs following neurological and/or psychological trauma, considered different from developmental stuttering (DS), which starts during early childhood with few if any new cases reported after adolescence. Here we report four cases of AS, two with apparent psychological trigger and two without, none with evidence of neurological injury, and none conforming to previously reported characteristics of psychogenic stuttering. We asked whether this group of AS would have similar speech and neuroanatomical characteristics to those with DS.

Functional but not structural networks of the human laryngeal motor cortex show left hemispheric lateralization during syllable but not breathing production.

The laryngeal motor cortex (LMC) is indispensible for the vocal motor control of speech and song production. Patients with bilateral lesions in this region are unable to speak and sing, although their nonverbal vocalizations, such as laughter and cry, are preserved. Despite the importance of the LMC in the control of voluntary voice production in humans, the literature describing its connections remains sparse.

Tissue-specific imaging is a robust methodology to differentiate in vivo T1 black holes with advanced multiple sclerosis-induced damage.

Background And Purpose: Brains of patients with multiple sclerosis (MS) characteristically have "black holes" (BHs), hypointense lesions on T1-weighted (T1W) spin-echo (SE) images. Although conventional MR imaging can disclose chronic BHs (CBHs), it cannot stage the degree of their pathologic condition. Tissue-specific imaging (TSI), a recently introduced MR imaging technique, allows selective visualization of white matter (WM), gray matter (GM), and CSF on the basis of T1 values of classes of tissue.

Thalamic involvement and its impact on clinical disability in patients with multiple sclerosis: a diffusion tensor imaging study at 3T.

Background And Purpose: Several studies suggest that grey matter involvement may play a role in multiple sclerosis (MS) pathology. Diffusion tensor imaging (DTI) at 3T was used to investigate the presence of damage to the normal-appearing thalamus in MS and its relationship with disability.

Materials And Methods: Twenty-four patients with relapsing-remitting (RR, n = 13, age = 41.

Focal white matter changes in spasmodic dysphonia: a combined diffusion tensor imaging and neuropathological study.

Spasmodic dysphonia is a neurological disorder characterized by involuntary spasms in the laryngeal muscles during speech production. Although the clinical symptoms are well characterized, the pathophysiology of this voice disorder is unknown. We describe here, for the first time to our knowledge, disorder-specific brain abnormalities in these patients as determined by a combined approach of diffusion tensor imaging (DTI) and postmortem histopathology.

Relationship between inflammatory lesions and cerebral atrophy in multiple sclerosis.

Objective: To investigate the temporal relationship between inflammation and cerebral atrophy in a longitudinal study of 19 patients with relapsing-remitting multiple sclerosis (RRMS) using serial monthly contrast enhanced MRI examinations and monthly measurements of brain fractional volume (BFV) for an average of 4 (range 2.4 to 10) years.

Methods: In this retrospective study, all patients had an active MRI scan at entry with a minimum of two new contrast enhancing lesions (CEL) on baseline MRI examinations.

Interferon-beta-1b effects on re-enhancing lesions in patients with multiple sclerosis.

Interferon-beta (IFNbeta) reduces the number and load of new contrast-enhancing lesions (CELs) in patients with multiple sclerosis (MS). However, the ability of IFNbeta to reduce lesion sizes and re-enhancements of pre-existing CELs has not been examined extensively. Activity of contrast re-enhancing lesions (Re-CELs) and contrast single-enhancing lesions (S-CELs) were monitored in ten patients with relapsing-remitting (RR) MS.

Estimating cerebral atrophy in multiple sclerosis patients from various MR pulse sequences.

Purpose: The purpose of this study was to determine how measures reflecting cerebral atrophy (CA) are influenced by pulse sequence (PS) and segmentation algorithm (SA) used in multiple sclerosis (MS) patients and healthy control (HC)s.

Methods: Magnetic resonance imaging (MRI) scans from 10 relapsing-remitting MS (RRMS) patients and five HCs were used to determine the change in brain fractional volume (BFV) over a two-year period. T1-weighted, fluid-attenuated inversion recovery (FLAIR), and proton density (PD)/T2-weighted sequences were analysed Image segmentation to determine brain volume was performed using the following a histogram SA, an adaptive fuzzy c-means algorithm (AFCM), and an adaptive Bayesian segmentation with a K-means clustering.

Comparison of methods for obtaining longitudinal whole-brain magnetization transfer measurements.

Purpose: To investigate whether the method of applying image masks can alter quantifiable measures determined from whole-brain MTR calculations.

Materials And Methods: Thirty-five T1/MT image pairs were obtained from five normal volunteers. For each pair a mask was used to specify the regions to be analyzed.

Interferon beta-1b and intravenous methylprednisolone promote lesion recovery in multiple sclerosis.

Objective: To determine whether lesion evolution in relapsing-remitting multiple sclerosis (RRMS) patients is altered by treatment with interferonbeta1b (IFNbeta-1b) or by intravenous methylprednisolone (IVMP) as measured by magnetization transfer imaging.

Methods: Magnetization transfer ratios (MTR) of 225 contrast enhancing lesions (CEL), in four RRMS patients were serially determined for 12 months before and 12-18 months after contrast enhancement in a baseline vs treatment trial with IFNbeta-1b. During the baseline period, 185 new CEL were identified: 76 were treated with IVMP (1 g/day x 5 days) and designated steroid CEL (S-CEL); the remaining 109 were considered baseline lesions (BCEL).

Characterization of differences between multiple sclerosis and normal brain: a global magnetization transfer application.

Background And Purpose: Although the exact nature of the physiological differences between normal and multiple sclerosis (MS) brains are unknown, it has been shown that their global magnetization transfer ratio (MTR) values are significantly different. To more fully understand these differences, we examined MTR values by using 30 distinct measures. We provide a unique illustration of these differences through a derived normal-to-MS transform.

Technical solution for an interactive functional MR imaging examination: application to a physiologic interview and the study of cerebral physiology.

Studies with functional magnetic resonance (MR) imaging produce large unprocessed raw data sets in minutes. The analysis usually requires transferring of the data to an off-line workstation, and this process frequently occurs after the subject has left the MR unit. The authors describe a hardware configuration and processing software that captures whole-brain raw data files as they are being produced from the MR unit.

Serial whole-brain magnetization transfer imaging in patients with relapsing-remitting multiple sclerosis at baseline and during treatment with interferon beta-1b.

Background And Purpose: To determine whether occult disease fluctuates with macroscopic lesions during the natural history of multiple sclerosis (MS) and whether therapeutic interventions affect occult disease, we performed serial monthly magnetization transfer (MT) imaging in patients with relapsing-remitting MS in a crossover trial with interferon beta-lb.

Methods: Serial whole-brain magnetization transfer ratios (MTRs) in eight patients with relapsing-remitting MS and in four control subjects were plotted as normalized histograms, and MTR parameters were compared with contrast-enhancing lesions and bulk white matter lesion load.

Results: In patients with relapsing-remitting MS, the histographic peak of 0.

Study of relapsing remitting experimental allergic encephalomyelitis SJL mouse model using MION-46L enhanced in vivo MRI: early histopathological correlation.

MION-46L, a superparamagnetic iron oxide contrast agent, was investigated for its ability to increase the sensitivity of in vivo 3D MRI in the detection of brain lesions in a chronic experimental allergic encephalomyelitis (crEAE) mouse model. Lesion conspicuity on postcontrast 3D MRI was dramatically enhanced as compared to precontrast images corresponding to areas of inflammatory and demyelinating lesions. MION-46L could be detected on Prussian blue iron stain in the vascular endothelium, the perivascular space, and in macrophages within perivascular cuffs and areas of inflammation and demyelination.

Analysis of interpolation effects in the reslicing of functional MR images.

Purpose: Typically, the final step in volume registration is the reslicing of the volume of interest. The purpose of this work is to examine the effects of this reslicing on functional MRI (fMRI) data using different interpolation methods.

Method: Functional whole-brain echo planar imaging (EPI) volumes were resliced using six different interpolation methods: trilinear, tricubic splines, and a 3D sinc function using a rectangular and a Hanning window, both with half-window lengths of 3 and 4 voxels.

Measuring registration potential in planar transmission images.

One method of detecting change in an anatomical structure is by comparing elements of a longitudinal series of planar transmission images (i.e. radiographs).

Correspondence of closest gradient voxels--a robust registration algorithm.

A robust, automatic volume registration algorithm based on intensity gradients is presented. This algorithm can successfully perform registrations under conditions of unrelated intervolume voxel intensities, significant object displacements, and/or significant amounts of missing data. It also allows the user to visualize the registration convergence, clearly illustrating any source of registration errors.

The effect of independent film and object rotation on projective geometric standardization of dental radiographs.

Digital alignment of dental X-ray images using projective invariants has been shown to be a feasible method for detecting changes through digital subtraction radiography. Previous research on the validity of the standardization procedure has considered the effects of motion of the X-ray source alone. Here the effects of independent motion of the film and the object on the standardization are investigated.

Registration of dental radiographs using projective geometry.

Dunn and van der Stelt recently introduced a new model of radiographic image registration which makes use of the correspondence of 3D structures (Dunn SM, van der Stelt P. Dentomaxillofac Radiol 1992; 21: 142-7; Dunn SM et al. Dentomaxillofac Radiol 1993; 22: 77-80).