Try a new search

Format these results:

Searched for:

person:charlr01

Total Results:

23


Rapid quantitative magnetization transfer imaging: Utilizing the hybrid state and the generalized Bloch model

Assländer, Jakob; Gultekin, Cem; Mao, Andrew; Zhang, Xiaoxia; Duchemin, Quentin; Liu, Kangning; Charlson, Robert W; Shepherd, Timothy M; Fernandez-Granda, Carlos; Flassbeck, Sebastian
PURPOSE/OBJECTIVE:To explore efficient encoding schemes for quantitative magnetization transfer (qMT) imaging with few constraints on model parameters. THEORY AND METHODS/METHODS:We combine two recently proposed models in a Bloch-McConnell equation: the dynamics of the free spin pool are confined to the hybrid state, and the dynamics of the semi-solid spin pool are described by the generalized Bloch model. We numerically optimize the flip angles and durations of a train of radio frequency pulses to enhance the encoding of three qMT parameters while accounting for all eight parameters of the two-pool model. We sparsely sample each time frame along this spin dynamics with a three-dimensional radial koosh-ball trajectory, reconstruct the data with subspace modeling, and fit the qMT model with a neural network for computational efficiency. RESULTS:We extracted qMT parameter maps of the whole brain with an effective resolution of 1.24 mm from a 12.6-min scan. In lesions of multiple sclerosis subjects, we observe a decreased size of the semi-solid spin pool and longer relaxation times, consistent with previous reports. CONCLUSION/CONCLUSIONS:The encoding power of the hybrid state, combined with regularized image reconstruction, and the accuracy of the generalized Bloch model provide an excellent basis for efficient quantitative magnetization transfer imaging with few constraints on model parameters.
PMID: 38073093
ISSN: 1522-2594
CID: 5589482

On multi-path longitudinal spin relaxation in brain tissue

Assländer, Jakob; Mao, Andrew; Beck, Erin S; Rosa, Francesco La; Charlson, Robert W; Shepherd, Timothy M; Flassbeck, Sebastian
The purpose of this paper is to confirm previous reports that identified magnetization transfer (MT) as an inherent driver of longitudinal relaxation in brain tissue by asserting a substantial difference between the $T_1$ relaxation times of the free and the semi-solid spin pools. Further, we aim to identify an avenue towards the quantification of these relaxation processes on a voxel-by-voxel basis in a clinical imaging setting, i.e. with a nominal resolution of 1mm isotropic and full brain coverage in 12min. To this end, we optimized a hybrid-state pulse sequence for mapping the parameters of an unconstrained MT model. We scanned 4 people with relapsing-remitting multiple sclerosis (MS) and 4 healthy controls with this pulse sequence and estimated $T_1^f \approx 1.90$s and $T_1^s \approx 0.327$s for the free and semi-solid spin pool of healthy WM, respectively, confirming previous reports and questioning the commonly used assumptions $T_1^s = T_1^f$ or $T_1^s = 1$s. Further, we estimated a fractional size of the semi-solid spin pool of $m_0^s \approx 0.202$, which is larger than previously assumed. An analysis of $T_1^f$ in normal appearing white matter revealed statistically significant differences between individuals with MS and controls. In conclusion, we confirm that longitudinal spin relaxation in brain tissue is dominated by MT and that the hybrid state facilitates a voxel-wise fit of the unconstrained MT model, which enables the analysis of subtle neurodegeneration.
PMCID:9882584
PMID: 36713253
ISSN: 2331-8422
CID: 5473602

Home-administered transcranial direct current stimulation is a feasible intervention for depression: an observational cohort study

Charvet, Leigh; George, Allan; Charlson, Erik; Lustberg, Matthew; Vogel-Eyny, Amy; Eilam-Stock, Tehila; Cho, Hyein; Best, Pamela; Fernandez, Luis; Datta, Abhishek; Bikson, Marom; Nazim, Kamran; Pilloni, Giuseppina
Transcranial direct current stimulation (tDCS) is an emerging treatment for major depression. We recruited participants with moderate-to-severe major depressive episodes for an observational clinical trial using Soterix Medical's tDCS telehealth platform as a standard of care. The acute intervention consisted of 28 sessions (5 sessions/week, 6 weeks) of the left anodal dorsolateral prefrontal cortex (DLPFC) tDCS (2.0 mA × 30 min) followed by a tapering phase of weekly sessions for 4 weeks (weeks 7-10). The n = 16 completing participants had a significant reduction in depressive symptoms by week 2 of treatment [Montgomery-Åsberg Depression Rating Scale (MADRS), Baseline: 28.00 ± 4.35 vs. Week 2: 17.12 ± 5.32, p < 0.001] with continual improvement across each biweekly timepoint. Acute intervention responder and remission rates were 75 and 63% and 88 and 81% following the taper period (week 10).
PMCID:10477781
PMID: 37674552
ISSN: 1664-0640
CID: 5602552

Development and validation of a simple and practical tool for differentiating MS from other idiopathic inflammatory demyelinating diseases of CNS with brain MRI [Meeting Abstract]

Patel, J.; Pires, A.; Derman, A.; Fatterpekar, G.; Charlson, E.; Oh, C.; Kister, I.
ISI:000706771301337
ISSN: 1352-4585
CID: 5074082

Combined Central and Peripheral Nervous System Demyelination: An Unusual Presentation of MOG Antibody Disorder [Meeting Abstract]

Patel, J; Charlson, R
Background: MOG antibody disorder (MOGAD) is associated with diverse clinical phenotypes, including recurrent and bilateral optic neuritis, acute disseminated encephalomyelitis, and longitudinally extensive transverse myelitis with a predilection for the conus medullaris. Spinal nerve root involvement in this disease has rarely been described.
Objective(s): To describe a case of MOG antibody disorder with an unusual radiographic presentation.
Method(s): A case is described and review of the literature was performed.
Result(s): A 53-year-old previously healthy man presented to our hospital with three weeks of numbness and pain involving his right arm, bilateral lower extremities, and perineum. Neurologic exam was notable for decreased sensation in his right hand and left leg, hyperreflexia in bilateral lower extremities, and an extensor plantar response on the left. MRI spine was notable for multifocal short-segment T2 hyperintense lesions consistent with demyelination. There was also contrast enhancement of the cauda equina nerve roots and focal lobular enhancement of the left S1 nerve root. MRI brain showed several small T2 hyperintense brainstem lesions. He was started on pulse dose intravenous steroids while undergoing extensive work-up for inflammatory, infectious, and neoplastic causes. Serology was notable for mildly elevated ACE. CSF showed elevated protein. Given these laboratory and radiographic findings, an inflammatory etiology such as neurosarcoidosis was initially felt to be most likely. CT chest was negative for evidence of pulmonary sarcoid. He demonstrated clinical improvement with steroids and was discharged on a slow taper. MOG antibody in the serum (by cell-based assay) resulted positive at 1:100, suggestive of demyelination in the setting of MOGAD. The patient opted for monthly IV immunoglobulin (IVIG) maintenance therapy and has been clinically stable. Repeat MRI two months later showed stable areas of spinal nerve root enhancement and decrease in some of the cord lesions.
Conclusion(s): Our case demonstrates that MOGAD should be a diagnostic consideration when MRI shows spinal nerve root enhancement in the appropriate clinical context, especially with the additional presence of CNS lesions that are typical of demyelination. MOGAD can manifest clinically and radiographically in both the central and peripheral nervous system
EMBASE:635559994
ISSN: 1477-0970
CID: 5148372

Progressive myelopathy associated with spinal epidural lipomatosis in three non-obese patients with type 1 diabetes mellitus

Lotan, Itay; Charlson, Robert W; Fatterpekar, Girish M; Shapiro, Maksim; Smith, Michael L; William, Christopher; Kister, Ilya
BACKGROUND:Spinal epidural lipomatosis (SEL) is a rare condition defined as pathological overgrowth of the normally present epidural fat within the spinal canal. SEL is associated with Cushing disease, obesity and chronic corticosteroid therapy. Diabetes mellitus type 1 (DM1) has not known to be a risk factor for SEL. The neurological symptoms of SEL are attributed mainly to mechanical compression on the spinal cord and the cauda equina. METHODS:A retrospective chart review of patients evaluated at NYU Multiple Sclerosis Care Center identified three diabetic patients with progressive myelopathy associated with SEL. We report the clinical course, diagnostic workup and outcomes in these three patients with SEL-associated myelopathy. RESULTS:Three patients (2 females and 1 male) had long-standing DM1 and developed progressive myelopathy in their early 40's. All were found to have thoracic SEL (extensive extradural T1, T2 hyperintense signal; biopsy confirmed in one case) with associated extensive abnormal cord signal in lower cervical/upper thoracic spinal cord. A comprehensive evaluation for metabolic, infectious, autoimmune and vascular causes of myelopathy that included serologies, cerebrospinal fluid analyses, and spinal angiography did not reveal an alternative cause for myelopathy. One of the patients underwent a surgical decompression of SEL with subsequent clinical and radiologic improvement. CONCLUSIONS:Our case series suggest that patients with DM1 and myelopathy of unknown cause should be evaluated for SEL. Timely diagnosis and appropriate intervention may forestall progression of neurological disability and even result in neurologic improvement. SEL should be considered on the short list of diagnoses that cause potentially reversible progressive myelopathy.
PMID: 31972349
ISSN: 1878-5883
CID: 4273332

RITUXIMAB AND PREGNANCY IN NEUROIMMUNOLOGICAL DISORDERS: A RETROSPECTIVE STUDY [Meeting Abstract]

Ge, Lily; Kister, Ilya; Charlson, Robert; Howard, Jonathan; Krupp, Lauren; Ryerson, Lana Zhovtis
ISI:000536058004004
ISSN: 0028-3878
CID: 5192122

Spinal epidural lipomatosis with progressive myelopathy in patients with Type 1 Diabetes Mellitus: a novel association? [Meeting Abstract]

Kister, Ilya; Charlson, Robert; Fatterpekar, Girish; Smith, Michael; Shapiro, Maksim; William, Christopher; Lotan, Itay
ISI:000536058004221
ISSN: 0028-3878
CID: 4561452

Effectiveness of Subcutaneous Tocilizumab therapy in Neuromyelitis Optica Spectrum Disorder [Meeting Abstract]

Lotan, Itay; Charlson, Robert; Ryerson, Lana Zhovtis; Levy, Michael; Kister, Ilya
ISI:000536058004232
ISSN: 0028-3878
CID: 4561472

Which Brain Lesion Locations Differentiate Multiple Sclerosis (MS) from Neuromyelitis Optica Spectrum Disorders (NMOSD) and MOG Antibody Disorder (MOGAD)? [Meeting Abstract]

Patel, Jasmin; Pires, Antonio; Derman, Anna; Charlson, Erik; Fatterpekar, Girish; Kister, Ilya
ISI:000536058005001
ISSN: 0028-3878
CID: 4561492