High-resolution computed tomography in multiple sclerosis

Subcortical arteriosclerotic encephalopathy (Binswanger's disease). Presentation of two cases

Subcortical arteriosclerotic encephalopathy (SAE) (Binswanger's disease) was previously diagnosed almost exclusively at autopsy and considered to be very rare. Recent studies, however, indicate that an in vivo diagnosis might be made by means of computed tomography (CT) or nuclear magnetic resonance, resulting in a much more frequent recognition of this chronic encephalopathy of middle-aged, hypertensive patients. Two cases are presented, in which the clinical and CT findings made a diagnosis of SAE very probable.

CT scan changes in multiple sclerosis among Malaysian patients

A study of 12 patients with clinically definite multiple sclerosis (CDMS) using high dose infusion CT showed overall abnormality of 75% with an average of 2.5 lesions per patient. 75% of the patients showed abnormality of the cerebrum, mostly asymptomatic. The main changes were ventricular dilatation and asymmetry, isolated or generalized cerebral atrophy, areas of low attenuation mainly in the deeper parts of the cerebrum and the peri-ventricular area. 25% of the patients showed changes in the brainstem and none was seen in the cerebellum. The abnormality was more florid in patients with clinically disseminated forms of the disease. The study demonstrated that asymptomatic cerebral involvement is common among Asian patients with MS and CT is a useful tool in the overall assessment and diagnosis of Asian MS patients.

Quantitation of blood-brain barrier defect by magnetic resonance imaging and gadolinium-DTPA in patients with multiple sclerosis and brain tumors

In this study quantitation of the degree of deficiency of the blood-brain barrier (BBB) in patients with multiple sclerosis or brain tumors, by using MRI, is shown to be possible. As a measure of permeability of the BBB to Gadolinium-DTPA (Gd-DTPA) the flux per unit of distribution volume per unit of brain mass was used. This quantity was found by introducing the longitudinal relaxation rate (R1) as a measure of concentration of Gd-DTPA in the brain tissue in the mathematical model for the transcapillary transport over the BBB. High accordance between the observed data points and the model was found, and the results were comparable to results obtained from similar studies using positron emission tomography. The improved possibility of quantitating the defect of the BBB by MRI may give new information about pathogenesis or etiology, and leads to improved methods in monitoring the efficacy of treatments in intracranial diseases.

Quantitative assessment of blood-brain barrier permeability in multiple sclerosis using 68-Ga-EDTA and positron emission tomography

Fifteen patients with definite multiple sclerosis were examined with high volume delayed (HVD) CT scan and positron emission tomography (PET) using 68-Ga-EDTA as a tracer. The passage of 68-Ga-EDTA across the blood-brain barrier (BBB) was measured by using multiple graphical analysis. This method permits the simultaneous calculation of a blood to brain influx constant Ki (ml/g-1 min-1) and of the plasma volume Vp (ml/g-1). Focal areas of abnormal CT enhancement and pathological accumulation of 68-Ga-EDTA were visualised in four patients who were all examined during a clinical exacerbation of the disease. The mean Ki value measured in these areas was 12.5, SD 3.4 indicating a moderate but significant increase of BBB permeability compared with the value found in normal tissue (3.2, SD 0.9). No parallel increase in Vp values was found in these pathological areas. Quantitative data obtained with PET seems to provide further insight into the study of BBB function in multiple sclerosis.

Immunohistochemical and electron microscopic techniques in the diagnosis of viral encephalitides

Electron microscopy and in particular, immunohistochemical examination techniques have substantially improved the chances to attain an etiologic diagnosis in viral encephalitis. The application of these techniques is needed first of all in the examination of cerebral biopsy specimens, but they can contribute to the clearing of the etiology at post mortem study of the brain, too. This review outlines the basic techniques and their application fields. In immunohistochemistry beside the demonstration of specific viral antigens the analysis of the humoral and cellular immune reactions and the identification of the cell types involved by cell specific markers is also important. The second part of the review gives a synopsis of the results of electron microscopic and immunohistochemical studies in the most important acute, subacute and chronic encephalitides occurring in Europe.

Multiple sclerosis: correlation of magnetic resonance imaging with cerebrospinal fluid findings

MRI examination of 41 patients with clinical definite multiple sclerosis showed white matter lesions of high proton T2 signal consistent with demyelination in 76% and CSF abnormalities present in 76%. Of patients with CSF abnormalities, 26% had normal MRI scans; conversely 26% of patients with MRI abnormalities had negative CSF studies. Thus a significant number of multiple sclerosis patients had negative results on either MRI or CSF examination, while only 5% had normal results on both tests.

Magnetic resonance imaging and clinical relationships in multiple sclerosis

Magnetic resonance imaging (MRI) was done in 109 patients with suspected demyelinating disease (56 with clinical multiple sclerosis [MS] and 53 without). Of those with clinical MS, 43 (77%) had multifocal lesions of the white matter detected on MRI; 12 of the 43 also had confluent periventricular signaling. Nine patients (17%) without clinical MS had similar findings. Of the 56 patients with MS, 35 underwent both computed tomography (CT) and MRI. In this group, 80% of MRI scans showed multiple demyelinating lesions compatible with MS, as compared with 29% of the CT scans. A CT scan was "positive" more often if obtained within 1 month after an attack of MS than later. In contrast, the sensitivity of MRI or the number of lesions detected by MRI did not increase in patients with recent exacerbations. MRI was "positive" in patients with clinical MS more often than was any single evoked response study. In statistical analyses, both the sensitivity of MRI and the number of lesions were associated with the duration of MS. A pattern of confluent periventricular signaling around the lateral ventricle was associated with greater duration of MS and patient disability.

Multiple sclerosis disease activity correlates with gadolinium-enhanced magnetic resonance imaging

Magnetic resonance imaging provides a method of visualizing multiple sclerosis plaques, but the age and activity of these plaques cannot be determined with routine magnetic resonance images. Gadolinium DTPA is a paramagnetic contrast agent that does not cross an intact blood-brain barrier. We studied 16 patients with multiple sclerosis, using magnetic resonance imaging, gadolinium-enhanced magnetic resonance imaging, and computed tomographic scans. Gadolinium enhancement of multiple sclerosis plaques correlated with the clinical activity of the disease and corresponded anatomically with the symptoms and signs. We conclude that gadolinium enhancement of magnetic resonance images is a promising tool in the investigation of multiple sclerosis lesions and that it may provide a method for objective follow-up in clinical trails.