Romy Hoque

Use of perfusion- and diffusion-weighted imaging in differential diagnosis of acute and chronic ischemic stroke and multiple sclerosis

Abstract Objective: To investigate differences in lesions and surrounding normal appearing white matter (NAWM) by perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) in patients with acute and chronic ischemic stroke and multiple sclerosis (MS). Methods: Study subjects included 45 MS patients, 22 patients with acute ischemic stroke and 20 patients with chronic ischemic stroke. All subjects underwent T2-weighted imaging (WI), flair attenuated inversion recovery (FLAIR), DWI and dynamic contrast enhanced PWI. Apparent diffusion coefficient (ADC) and mean transit time (MTT) maps were generated and values were calculated in the acute and chronic ischemic and demyelinating lesions, and in NAWM for distances of 5, 10 and 15 mm. Fifty-three acute ischemic and 33 acute demyelinating lesions, and 775 chronic ischemic and 998 chronic demyelinating lesions, were examined. Univariate, multivariate and data mining analyses were used to examine the feasibility of a prediction model between different lesion types. Correctly and incorrectly classified lesions, true positive (TP), false positive (FP) and precision rates were calculated. Results: Patients with acute ischemic lesions presented more prolonged mean MTT values in lesions (p=0.002) and surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001) than those with acute demyelinating lesions. In multinomial logistic regression analysis, 65 of 86 acute lesions were correctly classified (75.6%). The TP rates were 81.1% for acute ischemic lesions and 66.7% for acute demyelinating lesions. The FP rates were 33.3% for acute ischemic and 18.9% for acute demyelinating lesions. The precision was 79.6% for classification of acute ischemic lesions and 68.8% for prediction of acute demyelinating lesions. The logistic model tree decision algorithm revealed that prolonged MTT of surrounding NAWM for a distance of 15 mm (≥7459.2 ms) was the best classifier of acute ischemic versus acute demyelinating lesions. Patients with chronic ischemic lesions presented higher mean ADC (p<0.0001) and prolonged MTT (p=0.013) in lesions, and in surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001), compared to the patients with chronic demyelinating lesions. Data mining analyses did not show reliable predictability for correctly discerning between chronic ischemic and chronic demyelinating lesions. The precision was 56.7% for classification of chronic ischemic and 58.9% for prediction of chronic demyelinating lesions. Discussion: We found prolonged MTT values in lesions and surrounding NAWM of patients with acute and chronic ischemic stroke when compared to MS patients. The use of PWI is a promising tool for differential diagnosis between acute ischemic and acute demyelinating lesions. The results of this study contribute to a better understanding of the extent of hemodynamic abnormalities in lesions and surrounding NAWM in patients with MS.

The Role of Quantitative Neuroimaging Indices in the Differentiation of Ischemia From Demyelination: An Analytical Study With Case Presentation

BACKGROUND AND PURPOSE Differentiation of acute and subacute ischemic stroke lesions from acute demyelinating lesions of multiple sclerosis (MS) may not be possible on conventional magnetic resonance imaging (MRI). Both lesion types enhance on T1 with gadolinium (Gd) contrast and both are hyperintense on diffusion-weighted imaging (DWI). This study is an analysis of two quantitative MR indices: (1) calculated apparent diffusion coefficients (ADCs) and (2) T2 relaxation times (T2R) as means toward differentiating acute ischemic lesions from acute demyelinating lesions. Chronic ischemic and demyelinating lesions were evaluated for comparison as well. METHODS The MRI of nine patients with both acute and chronic ischemic lesions and six patients with both acute and chronic demyelinating lesions were analyzed for ADC and T2Rs. The indices were measured by manually placing regions of interest (ROIs) at the anatomic center of the acute lesion. Acute ischemic lesions were chosen by their hyperintensity on DWI and hypointensity on ADC mapping. Acute demyelinating lesions were selected by peripheral contrast enhancement after the administration of Gd. Computation of the ADC involved the diffusion coefficient on a region by region basis as follows: D = -(b(0)/b(1000))ln(S(b1000)/S(b0)), where S(b1000) is the signal intensity on DWI and S(b0) is the signal intensity on T2 with diffusion sensitivities of b(0) and b(1000), respectively. Computation of the T2R was made as follows: T2R = (TE(T2)--TE(PD))/(ln SI(PD)--ln SI(T2)), where TE is the echo time of the different pulse sequences, SI is signal intensity on the different echo sequences, and PD represents proton density sequence. RESULTS Twenty-nine acute ischemia, 27 acute demyelination, 28 chronic ischemia, and 43 chronic demyelination image sets were analyzed. The differences between ADC(acute infarct) (0.760) versus ADC(acute plaque) (1.106) were significant (p < 0.02). The differences between T2R(acute infarct) (235.5) versus T2R(acute plaque) (170.5) were also significant (p < 0.02). CONCLUSIONS ADC in combination with T2R is a useful tool to differentiate acute ischemic from acute demyelinating lesions. The use of these neuroimaging indices along with magnetic resonance spectroscopy metabolite ratios is then demonstrated in elucidating the pathophysiological mechanism for a case of delayed posttraumatic bilateral internuclear ophthalmoplegia.

The Cerebellum and Sleep

The importance of the cerebellum in sleep disorders, and vice versa, is only beginning to be understood. Advanced neuroimaging modalities have revealed cerebellar changes in both common and rare sleep disorders. Sleep disorders in those with genetic cerebellar disease, such as spinocerebellar ataxia, Friedreich ataxia, Joubert syndrome, and ataxia-telangiectasia, include excessive daytime sleepiness, restless legs syndrome, periodic limb movements of sleep, obstructive apnea, central apnea, and rapid eye movement behavior disorder. Sleep medicine is an important and under-recognized part of the neurologic evaluation in those with cerebellar disease.

Brachial neuritis with bilateral diaphragmatic paralysis following herpes zoster: a case report.

We present a case of supine respiratory failure due to a bilateral diaphragmatic paralysis associated with brachial neuritis secondary to thoracic herpes zoster. Fluoroscopy in both the standing and supine positions revealed bilateral diaphragmatic paralysis accentuated in the supine position. To our knowledge, this is the first case of thoracic herpes zoster associated with brachial neuritis and bilateral diaphragmatic paralysis.

Sleep-wake pattern following gunshot suprachiasmatic damage.

BACKGROUND The suprachiasmatic nucleus (SCN) plays a critical role in maintaining melatonin and sleep-wake cycles. METHODS/PATIENT We report a case of 38-year-old woman who, after gunshot wound to the right temple, developed a sleep complaint of multiple nocturnal awakenings and several naps throughout the day. RESULTS Computerized tomography and magnetic resonance imaging revealed bilateral optic nerve and optic chiasm damage. Diagnostic polysomnography and actigraphy revealed an irregular sleep wake rhythm. CONCLUSIONS We speculate concurrent damage of the SCN and optic nerves bilaterally resulted in the posttraumatic irregular sleep-wake rhythm.

Neurosarcoidosis: clinical features, diagnosis, and management.

Sarcoidosis is a multisystemic granulomatous disease, which uncommonly affects nervous system. However, when present, it may affect both central and peripheral nervous systems and potentially mimics other chronic diseases of the nervous system. Pathogenesis of neurosarcoidosis remains largely unknown, and its diagnosis and management pose serious challenges to clinicians. Early diagnosis and aggressive treatment of neurosarcoidosis are necessary to produce satisfactory clinical outcomes. This review discusses clinical manifestations, current diagnostic studies, and currently available modalities for management of neurosarcoidosis.

Cryptococcal meningitis presenting as pseudosubarachnoid hemorrhage.

A 50-year-old man presented with progressive visual loss, headache, and two days of confusion. A computed tomography of his head suggested subarachnoid hemorrhage with accompanying right parietal ischemic infarction. The magnetic resonance image was consistent with right parietal perisulcal pial and superficial cortical inflammation; a subjacent vasogenic edema with a 1 cm diameter abscess was also present. Funduscopy revealed bilateral multifocal choroidal lesions and retinal perivascular sheathing. He was diagnosed with pseudosubarachnoid hemorrhage secondary to cryptococcal meningitis and choroidal microabscesses with retinal inflammation after a cerebrospinal fluid (CSF) examination revealed cryptococcal yeast forms, as well as high titers of CSF cryptococcal antigen, but no CSF red blood cells.

Painful brachial plexopathies in SEPT9 mutations : adverse outcome related to comorbid states

Hereditary neuralgic amyotrophy (HNA), an autosomal dominant disorder associated with SEPT9 mutation located on chromosome 17q25, causes recurrent painful weakness with sensory disturbances in a brachial distribution. We present electrophysiological, clinical phenotype, and molecular genetic data of three members from a family with HNA with the C262T SEPT9 mutation. The degree of motor weakness and recovery is variable within this family. Severity and recovery from motor deficits may have been a function of comorbid medical conditions. To our knowledge, this is the first report to confirm SEPT9 mutation in a family with suspected HNA.

Manual Characterization of Sleep Spindle Index in Patients with Narcolepsy and Idiopathic Hypersomnia

This is a retrospective review of PSG data from 8 narcolepsy patients and 8 idiopathic hypersomnia (IH) patients, evaluating electrophysiologic differences between these two central hypersomnias. Spindles were identified according to the AASM Manual for the Scoring of Sleep and Associated Events; and counted per epoch in the first 50 epochs of N2 sleep and the last 50 epochs of N2 sleep in each patients PSG. Spindle count data (mean ± standard deviation) per 30 second-epoch (spindle index) in the 8 narcolepsy patients was as follows: 0.37 ± 0.73 for the first 50 epochs of N2; 0.65 ± 1.09 for the last 50 epochs of N2; and 0.51 ± 0.93 for all 100 epochs of N2. Spindle index data in the 8 IH patients was as follows: 2.31 ± 2.23 for the first 50 epochs of N2; 2.84 ± 2.43 for the last 50 epochs of N2; and 2.57 ± 2.35 for all 100 epochs of N2. Intergroup differences in spindle count in the first 50 N2 epochs, the last 50 N2 epochs, and all 100 epochs of scored N2 were significant (P < 0.01) as were the intragroup differences between the first 50 N2 epochs and the last 50 N2 epochs.

Central apnea at electroencephalographic seizure onset

2013 Elsevier B.V. All rights reserved. tachycardia, bradycardia, tonic contraction on surface electromyography of mentalis muscles and tibialis anterior muscles, and seizure semiology on video were all absent. Fig. 1B shows a 30-s epoch at the termination of the central apnea. Electrodecre