Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Orbital involvement as the initial manifestation of sarcoidosis: magnetic resonance imaging findings.
A 74-year-old man had diplopia, painful right ophthalmoplegia, proptosis, conjunctival injection, and facial skin lesions. Magnetic resonance imaging (MRI) revealed infiltration of the right intraorbital adipose tissue. ⋯ Treatment with corticosteroids and chlorambucil led to a full clinical recovery. Sarcoidosis should be considered in the evaluation of orbital pseudotumor in elderly patients, even if no systemic manifestations of sarcoidosis are present.
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Isolated infarcts in the periaqueductal region are rare but have been reported after cardiac catheterization. The authors report a case of dorsal midbrain infarct which caused bilateral ptosis, partial upgaze paresis, and internuclear ophthalmoplegia imaged within eight hours with diffusion-weighted imaging (DWI). The lesion was later confirmed on T2-weighted images. Diffusion-weighted imaging can rapidly confirm the diagnosis of this rare brain-stem infarct.
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Based on the authors' experience with reconstruction of the heart using three-dimensional echocardiography, the authors assessed the feasibility of three-dimensional reconstruction of brain images using transfontanelle ultrasound in selected cases of infants with abnormal intracranial findings. A conventional 5-MHz ultrasound transducer inside a transducer holder was rotated 180 degrees around its vertical axis using a computer-controlled stepper motor to acquire multiple sequential cross-sections of the brain. The raw digital data of this three-dimensionally recorded dataset were transferred to a PC-based workstation for further analysis. ⋯ In other 2-week-old newborns, the extension and volume of a periventricular hemorrhage was visualized by three-dimensional reconstruction of coronal cross-sectional images from the acquired three-dimensional dataset. The three-dimensional reconstruction of the lateral ventricles allowed the three-dimensional visualization and estimation of ventricular dilatation in milliliters in an 8-week-old infant with hydrocephalus. Three-dimensional reconstruction of brain images and volume estimation of brain lesions and cavities by ultrasound may provide new insights into the morphology and extension of ultrasonographically visible brain lesions.
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The authors compared two new rapid MRI techniques: double-shot echo-planar imaging (DS-EPI) versus double-shot fast spin-echo (DS-FSE) in the evaluation of cerebral lesions. The authors examined 35 patients with 37 lesions, which were hyperintense on long TR images. Patients were scanned with both DS-EPI and DS-FSE with a time of repetition (TR) of 10,000 milliseconds and an echo time (TE) of 80 milliseconds. ⋯ Whereas DS-FSE and DS-EPI are comparable in their ability to depict hyperintense cerebral pathology, DS-EPI is more time-efficient, and therefore appears preferable. Because of the high magnetic susceptibility of DS-EPI, geometric distortion degrades visualization of lesions in the posterior fossa or near the sinuses. On the other hand, the high magnetic susceptibility results in high conspicuity of blood products.