The Shy-Drager syndrome (SDS) is a form of progressive autonomic nervous system failure (PAF) with orthostatic hypotension and associated extrapyramidal involvement that is often mistaken for Parkinson disease. SDS includes olivopontocerebellar atrophy and striatonigral degeneration which is attended by PAF. Eight patients with SDS were studied on a 0.5-T superconducting system utilizing T1-weighted inversion recovery (IR) and T2-weighted spin-echo pulse sequences and also on a 1.5-T system using spin-echo sequences. With IR sequences, atrophy of the putamina was demonstrated in patients with SDS that is consistent with findings of neuronal loss in these nuclei reported on postmortem examinations. An abnormal decrease in signal intensity of the putamina, particularly along their lateral and posterior portions, was also detected, predominantly on T2-weighted sequences, and in three cases on T1-weighted spin-echo sequences. Abnormalities were detected on both imagers but were shown with greater clarity on the 1.5-T device. SDS is the first disease in which convincing basal ganglia changes have been shown in vivo exclusively by MR imaging.

✓ Temporary cortical blindness as a complication of posterior angiography is reported in 11 patients and compared with 30 similar cases previously reported. Theoretical considerations of etiology implicate transitory alterations of the blood-brain barrier in the striate cortex.

Heterotopic gray matter, which previously had been associated with severe congenital malformations of the brain and developmental delay, was found without these associated conditions. The authors found ten cases of heterotopic gray matter on magnetic resonance (MR) images. The lesions had a signal intensity that was isointense compared with that of gray matter on T1, spin-density, and T2-weighted images. Nine of the ten cases were associated with a seizure disorder. The tenth case, discovered during a workup for metastatic lung disease, was confirmed with pathologic studies. Heterotopic gray matter is the presence of cortical neurons in an abnormal location, which may be periventricular (nodular) or within the white matter (laminar). A knowledge of heterotopic gray matter and its association with seizures may prevent the misinterpretation of findings on MR images.

The effect on the brain of the sex-linked recessive form of adrenoleukodystrophy was studied in 40 boys, 4-18 years old. All underwent computed tomography (CT) scanning; six underwent magnetic resonance (MR) imaging. MR showed a high sensitivity in demonstrating white matter disease. Auditory pathway disease was characterized as involvement of the lateral lemniscus and medial geniculate body, and visual pathway disease was characterized by lateral geniculate body, Meyer loop, and optic radiation involvement. Contrast-enhanced CT still proved to have a greater capacity (at this time) to show the active, advancing form of the disease and concomitant calcifications. This large CT series also demonstrated the broad and variable expressions of adrenoleukodystrophy, which allowed the unification of previously described atypical forms of the disease.

The significance of linear regions of altered signal intensity that appear in sagittal magnetic resonance (MR) images along the length of the spinal cord was investigated. Examinations were performed on ten healthy volunteers and one patient with spinal cord edema. A 0.5-T or a 1.5-T MR system was used. Sampling-related effects (Gibbs phenomenon) at spinal cord edges and cerebrospinal fluid interfaces can lead to different signal patterns within the spinal cord and canal. These artifacts cause problems in interpretation, especially with the use of small object-to-pixel size ratios, by obscuring anatomy and simulating pathologic conditions such as pseudosyringes. Analysis of these intensity variations and of their dependence on sampling may improve the clinical accuracy of MR imaging.