Imaging features of neurosyphilis.

Syphilis is an infectious disease caused by the spirochete Treponema pallidum, subspecies pallidum. Although its incidence has declined after the widespread availability of penicillin, it has recently re-emerged, especially in men who have sex with men and in people living with human immunodeficiency virus (HIV). The neurological manifestations of syphilis, generally known as neurosyphilis, may appear at any time during the infection, including the initial years after the primary infection. Neurosyphilis can be asymptomatic, only with cerebrospinal fluid abnormalities, or symptomatic, characterized by several different clinical syndromes, such as meningitis, gumma, meningovascular, brain parenchyma involvement, meningomyelitis, tabes dorsalis, and peripheral nervous system involvement. However, these syndromes may simulate several other diseases, making the diagnosis often a challenge. In addition, syphilis can also be vertically transmitted from mother to child during pregnancy, leading to neurological manifestations. Neuroimaging is essential to demonstrate abnormal brain or spinal cord findings in patients with neurosyphilis, aiding in the diagnosis, treatment, and follow-up of these patients. This article aims to review the imaging features of neurosyphilis, including the early and late stages of the infection.

Osteoid Osteoma Mimicking Arthritis.

ABSTRACT: Intra-articular osteoid osteoma may simulate arthritis, due to the intra-articular presence of prostaglandin, which leads to synovitis, joint effusion, pain, and high local temperature. Also, intra-articular osteoid osteoma may present with minimum or no cortical thickening. Therefore, a high suspicion is needed for a correct and early diagnosis. Perfusion weighted imaging, such as dynamic contrast-enhanced imaging, can aid in the localization of the tumor nidus, seen as an early arterial-phase focal enhancement after the gadolinium injection, with fast washout, as a result of its hypervascularity.

Magnetic resonance imaging features of COVID-19-related cranial nerve lesions.

The complete features of the neurological complications of coronavirus disease 2019 (COVID-19) still need to be elucidated, including associated cranial nerve involvement. In the present study we describe cranial nerve lesions seen in magnetic resonance imaging (MRI) of six cases of confirmed COVID-19, involving the olfactory bulb, optic nerve, abducens nerve, and facial nerve. Cranial nerve involvement was associated with COVID-19, but whether by direct viral invasion or autoimmunity needs to be clarified. The development of neurological symptoms after initial respiratory symptoms and the absence of the virus in the cerebrospinal fluid (CSF) suggest the possibility of autoimmunity.

COVID-19 associated with encephalomyeloradiculitis and positive anti-aquaporin-4 antibodies: Cause or coincidence?

Neurologic complications are being recognized as important outcomes of coronavirus disease 2019 (COVID-19). Pathogenesis is varied and incompletely understood, and may include neuroinvasion, indirect post-infectious neuroinflammation, and cerebrovascular pathologies. We present a case of COVID-19-related encephalomyeloradiculitis with clinical and magnetic resonance imaging characteristics of neuromyelitis optica spectrum disorders that was associated with anti-aquaporin-4 antibodies. Our case suggests post-infectious autoimmunity as a mechanism in at least a subset of patients with COVID-19-related neurologic disease.

Widespread white matter DTI alterations in mesial temporal sclerosis independent of disease side.

PURPOSE: The aim of this study was to evaluate white matter (WM) integrity in vivo in patients with unilateral mesial temporal sclerosis (MTS). METHODS: Diffusion tensor imaging (DTI) findings from patients with left-sided MTS (L-MTS; N = 14) and right-sided MTS (R-MTS; N = 13), all taking antiepileptic medication, were compared with those from gender- and age-matched controls; DTI was performed along 30 noncollinear directions in a 1.5-T scanner. Tract-based spatial statistics (TBSS) analysis was performed by creating a WM skeleton; 5000-permutation-based inference (threshold, p < 0.05) was used to identify fractional anisotropy (FA) abnormalities. Mean (MD), radial (RD), and axial diffusivities (AD) were projected onto the mean FA skeleton. RESULTS: Compared with the control groups, patients with MTS had decreased FA affecting widespread WM tracts as well as extensive areas with increased RD, bilaterally and independent of the disease side. Areas with decreased FA and increased RD overlapped substantially. There were no significant differences in DTI parameters between L-MTS and R-MTS patients. CONCLUSION: Diffusion tensor imaging abnormalities were observed within and beyond the temporal lobe in patients with MTS. Patients with R- and L-MTS had extensive bilateral abnormalities in comparison to controls. These findings suggest that MTS pathobiology involves diffuse dysfunction of WM tracts, even in areas with no direct connections to the hippocampus.

Longitudinal assessment of subcortical gray matter volume, cortical thickness, and white matter integrity in HIV-positive patients.

PURPOSE: To longitudinally evaluate the cortical thickness and deep gray matter structures volume, measured from T1 three-dimensional (3D) Gradient echo-weighted imaging, and white matter integrity, assessed from diffusion tensor imaging (DTI) of HIV-positive patients. MATERIALS AND METHODS: Twenty-one HIV-positive patients on stable highly active antiretroviral therapy (HAART) with CD4+ T lymphocytes count >200 cells/mL and viral load <50 copies/mL underwent two magnetic resonance imaging (MRI) scans with a median interval of 26.6 months. None of the patients had HIV-related dementia. T1 3D magnetization prepared rapid gradient echo-weighted imaging and DTI along 30 noncolinear directions were performed using a 1.5 Tesla MR scanner. FreeSurfer was used to perform cortical volumetric reconstruction and segmentation of deep gray matter structures. For tract-based spatial statistics analysis, a white matter skeleton was created, and a permutation-based inference with 5000 permutations, with a threshold of P < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The median, radial, and axial diffusivities were also projected onto the mean FA skeleton. RESULTS: There were no significant differences in cortical thickness, deep gray matter structures volumes or diffusivity parameters between scans at the two time points (considering P < 0.05). CONCLUSION: No longitudinal differences in cortical thickness, deep gray matter volumes, or white matter integrity were observed in an HIV-positive population on stable HAART, with undetectable viral load and high CD4+ T lymphocytes count. J. Magn. Reson. Imaging 2016;44:1262-1269.