Prevalence of MR imaging abnormalities in vitamin B12 deficiency patients presenting with clinical features of subacute combined degeneration of the spinal cord.

BACKGROUND AND AIMS: Subacute combined degeneration (SACD) of the spinal cord, characterized by degeneration of lateral and posterior columns, is often found in vitamin B12 deficiency. Our aim was to look for sensitivity of imaging in depicting the spinal cord abnormality in vitamin B12 deficient patients and to find any correlation of vitamin B12 levels with clinical scores/severity at time of presentation. MATERIAL AND METHODS: A total 54 patients with biochemically proven vitamin B12 deficiency were included in the study. In all these patients MR study of cervico-dorsal spine was done. All the patients after initiation of appropriate treatment were followed up for a minimum of two months. RESULTS: MRI showed cord signal abnormality in only 8 patients out of 54 patients with low sensitivity of 14.8%. After appropriate therapy, complete resolution of cord signal abnormalities was observed in all these 8 patients, on follow-up MR imaging. Significant negative correlation (r=-0.503, p<0.000) was seen between the clinical severity scores and initial vitamin B12 levels. CONCLUSION: Conventional MRI may not be a useful tool for the diagnosis of SACD as it has very low sensitivity. Inverse correlation of Vitamin B12 levels with clinical scoring suggests that initial serum vitamin B12 levels may help in predicting the clinical severity.

Imaging of meningitis and ventriculitis.

Central nervous system infections account for 1% of primary hospital admissions and 2% of nosocomial infections and when encountered require prompt diagnosis and initiation of specific treatment. Imaging findings are mostly nonspecific with respect to the causative pathogen. This article describes the anatomy of cranial meninges and extra-axial spaces of the brain. Characteristic findings and recent advances in neuroimaging of meningitis and its complications and ventriculitis are summarized, and certain noninfectious causes of meningitis and meningitis mimics are described.

Imaging of nonspecific (nonherpetic) acute viral infections.

Encephalitis is an acute infection of brain parenchyma characterized clinically by fever, headache, and an altered level of consciousness. In the twenty-first century several outbreaks of encephalitis have been reported. Urbanization and encroachment on natural environments, the ease of world travel, and global trade have led to the spread of vectors and viruses.

Imaging features of central nervous system fungal infections.

Fungal infections of the central nervous system (CNS) are rare in the general population and are invariably secondary to primary focus elsewhere, usually in the lung or intestine. Except for people with longstanding diabetes, they are most frequently encountered in immunocompromised patients such as those with acquired immunodeficiency syndrome or after organ transplantation. Due to the lack of inflammatory response, neuroradiological findings are often nonspecific and are frequently mistaken for tuberculous meningitis, pyogenic abscess or brain tumor. Intracranial fungal infections are being identified more frequently due to the increased incidence of AIDS patients, better radiological investigations, more sensitive microbiological techniques and better critical care of moribund patients. Although almost any fungus may cause encephalitis, cryptococcal meningoencephalitis is most frequently seen, followed by aspergillosis and candidiasis. The biology, epidemiology and imaging features of the common fungal infections of the CNS will be reviewed. The radiographic appearance alone is often not specific, but the combination of the appropriate clinical setting along with computed tomography or magnetic resonance may help to suggest the correct diagnosis.