Inter-scanner Variation Independent Descriptors for Constrained Diffeomorphic Demons Registration of Retina OCT.

PURPOSE: OCT offers high in-plane micrometer resolution, enabling studies of neurodegenerative and ocular-disease mechanisms via imaging of the retina at low cost. An important component to such studies is inter-scanner deformable image registration. Image quality of OCT, however, is suboptimal with poor signal-to-noise ratio and through-plane resolution. Geometry of OCT is additionally improperly defined. We developed a diffeomorphic deformable registration method incorporating constraints accommodating the improper geometry and a decentralized-modality-insensitive-neighborhood-descriptors (D-MIND) robust against degradation of OCT image quality and inter-scanner variability. METHOD: The method, called D-MIND Demons, estimates diffeomorphisms using D-MINDs under constraints on the direction of velocity fields in a MIND-Demons framework. Descriptiveness of D-MINDs with/without denoising was ranked against four other shape/texture-based descriptors. Performance of D-MIND Demons and its variants incorporating other descriptors was compared for cross-scanner, intra- and inter-subject deformable registration using clinical retina OCT data. RESULT: D-MINDs outperformed other descriptors with the difference in mutual descriptiveness between high-contrast and homogenous regions > 0.2. Among Demons variants, D-MIND-Demons was computationally efficient, demonstrating robustness against OCT image degradation (noise, speckle, intensity-non-uniformity, and poor through-plane resolution) and consistent registration accuracy [(4±4 µm) and (4±6 µm) in cross-scanner intra- and inter-subject registration] regardless of denoising. CONCLUSIONS: A promising method for cross-scanner, intra- and inter-subject OCT image registration has been developed for ophthalmological and neurological studies of retinal structures. The approach could assist image segmentation, evaluation of longitudinal disease progression, and patient population analysis, which in turn, facilitate diagnosis and patient-specific treatment.

Does long-term partial sodium channel blockade alter disease progression in MS? Evidence from a retrospective study.

BACKGROUND: There is accumulating evidence that long-term disability and disease progression in multiple sclerosis (MS) are due to prolonged sodium channel opening along demyelinated axons. Despite good evidence in animal models of MS that partial voltage-gated sodium channel (VGSC) blockade reduces disease progression, little is known about its effects in patients, despite widespread use of such agents in the symptomatic management of MS. OBJECTIVE: To determine if long-term exposure to the VGSC-blocking drug carbamazepine (CBZ) alters disease progression in MS. METHODS: Using a retrospective chart review of patients diagnosed with MS, we compared progression of disability between patients exposed the VGSC blocker CBZ with those who were not exposed to the drug. Both whole-group and matched case-control analyses were performed after correcting for the influence of age, gender, MS subtype, expanded disability status score at diagnosis, use of disease-modifying therapy, and year of initial therapy. The multiple sclerosis severity scale (MSSS) was used as a measure of disease severity. The primary outcome measure was MSSS score difference between groups. RESULTS: Four hundred patients were included; 51 received CBZ symptomatic therapy (average duration of therapy 27 months). There was no significant difference in mean MSSS between the two groups in either the whole group comparison (p = 0.63) or the matched analysis (p = 0.12). CONCLUSION: Despite preclinical evidence suggesting a neuroprotective role of VGSC blockers in animal models of MS, this retrospective study suggests that long-term exposure to the VGSC-blocking drug CBZ fails to alter long-term disability and disease progression in MS patients.

Optical coherence tomography does not support optic nerve involvement in amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: In recent years a possible non-motor involvement of the nervous system in amyotrophic lateral sclerosis (ALS) has come into the focus of research and has been investigated by numerous techniques. Optical coherence tomography (OCT) - with its potential to reveal neuroaxonal retinal damage - may be an appropriate tool to investigate whether the anterior visual pathway is involved. Our aim was to determine whether OCT-based measures of retinal nerve fiber layer, ganglion cell layer, inner nuclear layer and outer nuclear layer thickness are abnormal in ALS, or correlated with disease severity. METHODS: Seventy-six ALS patients (144 eyes) and 54 healthy controls (108 eyes; HCs) were examined with OCT, including automated intraretinal macular segmentation. ALS disease severity was determined with the Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised. RESULTS: There was no significant difference between ALS patients and HCs in any of the examined OCT measures. Moreover, OCT parameters showed no correlation with clinical measures of disease severity. CONCLUSIONS: These findings indicate that involvement of the anterior visual pathway is not one of the non-motor manifestations of ALS.

Cup to disc ratio by optical coherence tomography is abnormal in multiple sclerosis.

OBJECTIVE: To identify and characterize cup to disc ratio (CDR) and related optic nerve head abnormalities in multiple sclerosis (MS) using spectral domain optical coherence tomography (OCT). BACKGROUND: While CDR is routinely assessed by ophthalmologists in the evaluation of glaucoma, CDR and related optic nerve head metrics remain largely unexplored in MS. DESIGN/METHODS: Cirrus-HD (high density) OCT was used to evaluate average CDR, vertical CDR, optic disc area, optic cup volume, and neuro-retinal rim area in 105 MS patients and 88 age-matched healthy individuals. High-contrast (100%) visual acuity, 2.5% low-contrast letter acuity and 1.25% low-contrast letter acuity were assessed in 77 MS patients. Two-sample t-tests were used in the analysis of OCT-derived optic nerve head measures between healthy controls and MS patients. Multivariate regression (accounting for age and gender) was used to assess relationships between optic nerve head measures and visual function. RESULTS: Average CDR (p=0.007) and vertical CDR (p=0.005) were greater in MS patients compared to healthy controls, while neuro-retinal rim area was decreased in MS patients (p=0.001). CDR increased with retinal nerve fiber layer (RNFL) thinning (r=-0.29, p=0.001). 2.5% low-contrast (p=0.005) and 1.25% low-contrast letter acuity (p=0.03) were lower in MS patients with higher vertical CDR. CONCLUSIONS/RELEVANCE: CDR (as determined by spectral domain OCT) is abnormal in MS and correlates with visual function. OCT-derived CDR and related optic nerve head metrics may represent an objective measure by which to monitor disease progression, and potentially neuroprotection, in therapeutic MS trials.

Spontaneous intracranial hypotension.

INTRODUCTION: Spontaneous/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

Brachial neuritis masquerading as acute coronary syndrome.

BACKGROUND: Brachial neuritis is a frequently misdiagnosed condition which can present to many medical or surgical specialties. OBJECTIVE: To report a case of brachial neuritis with bilateral phrenic nerve involvement and diaphragmatic weakness. CASE DESCRIPTION: A 63-year-old man presented with acute-onset proximal upper extremity pain and weakness. He also developed severe orthopnoea. Examination revealed proximal upper limb wasting and dramatic paradoxical breathing. Cardiac investigations were unremarkable. Electromyographic studies were consistent with a C5 radiculopathy. Phrenic nerve studies were abnormal bilaterally and Sniff test was positive. A diagnosis of brachial neuritis with predominant C5 and bilateral phrenic nerve involvement was made. His symptoms resolved spontaneously over 3 months. CONCLUSIONS: Brachial neuritis can mimic an acute coronary syndrome and is a rare cause of bilateral phrenic neuropathy. Phrenic nerve palsy should be considered in patients presenting with shortness of breath without any underlying respiratory or cardiovascular illness.

Multiple sclerosis exceptionally presenting as parkinsonism responds to intravenous methylprednisolone.

Parkinsonism due to multiple sclerosis (MS) is rare. In previously reported patients with MS-induced parkinsonism, MS manifested first, followed a typical clinical course, and parkinsonism developed later in the course of the illness. We report a 52-year-old male presenting with parkinsonism as the initial manifestation of MS, in whom a subsequent MS relapse consisted of marked deterioration in parkinsonism, a clinical pattern not previously described in MS. A brain MRI demonstrated involvement of the substantia nigra and basal ganglia. This patient illustrates that the clinical presentation and progression of MS may rarely be characterised by predominating parkinsonian features which are reversible by treatment with intravenous methylprednisolone and interferon beta1a.

Acute aseptic meningitis and diffuse myelitis as the presenting features of neurological Behcet disease.

We report an explosive presentation of neurological Behcet disease, in an Irish male patient. We present the clinical and radiological findings in our patient and discuss a novel and effective therapeutic approach. We review other treatment modalities of patients with neurological involvement.