The Motion Artifact Suppression Technique (MAST) is a method which uses a series of gradient echos that are computed to cancel velocity, acceleration and pulsatility components of involuntary motion in MR imaging. A total of 916 patient studies were performed over a nine month period using MAST sequences with a TE 40, 60, 80, 100, 120, and 26/112. There was considerable improvement in long TR, long TE images. Cerebrospinal fluid flow artifacts were reduced. Body and spine images had reduced flow and respiratory artifacts. Spin rephasing in blood vessels caused increase intraluminal signal. This might be useful for cardiovascular imaging.

Blood Circulation↗

PubMedDate not supplied

Cerebral microvascular injury in experimental drug abuse.

An experimental drug abuse research project is reported, in which monkeys and rats were placed on various I.V. amphetamine (Desoxyn) and I.V. barbiturate (Seconal) regimes. The monkeys were studied by serial cerebral angiography. At the end of the study all animals were sacrificed for histological examination. I.V. methamphetamine produced relatively severe cerebral vascular injury and brain damage in most animals. At least part of the damage seemed to be the result of direct vascular injury, arterial and venous. The misuse of Seconal and Ritalin also appeared to be hazardous, but these studies are incomplete, and the degree of hazard has not been fully evaluated.

Animals↗

PubMedDate not supplied

MR imaging of cerebral toxoplasmosis: correlation of computed tomography and pathology.

A case of cerebral toxoplasmosis in a patient with acquired immune deficiency syndrome who was evaluated by both CT and magnetic resonance is reported. Magnetic resonance proved to be far more sensitive in detecting the intracranial lesions than CT.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

CT myelography in spinal cysticercosis.

Four cases of spinal cysticercosis were found in a series of 356 cases of CNS cysticercosis studied neuroradiologically. Cysticercal cysts were seen to migrate within the spinal subarachnoid space on myelographic studies. All four patients presented initially with hydrocephalus, which supports the notion that spinal leptomeningeal cysts have migrated from an intracranial site of origin. Computed tomographic myelography (metrizamide) allowed better localization and definition of the spinal cysticercal lesions.

Adult↗

PubMedDate not supplied

MR imaging of Chiari II malformation associated with dysgenesis of cerebellum and brain stem.

Extensive cerebellar hypogenesis is rare in Chiari II malformation and, to our knowledge, has not been described in modern radiological literature. In our case near total absence of cerebellar tissue and "underdevelopment" of the brain stem were noted in a patient with several characteristic features of Chiari II malformation.

Abnormalities, Multiple↗

PubMedDate not supplied

MR imaging of neurocysticercosis.

Magnetic resonance (MR) was performed in 50 patients with neurocysticercosis. Comparison was made with other neuroradiological imaging modalities including CT, myelography, CT ventriculography, and CT myelocisternography. Eighteen patients were found to have intraventricular cysts. In several patients, these were multiple and 22 intraventricular cysts were discovered. Although 4 of the 22 ventricular cysts were missed by MR, T1-weighted images can play a significant role in the early detection of intraventricular cysticercosis cysts, showing the cyst wall (9 of 22), a high intensity mural nodule (6 of 22), and increased signal intensity of the cyst fluid (5 of 22). Cisternal cysts (14 cysts in 10 patients) could be identified; they appear similar to intraventricular cysts, but mural nodules are infrequently seen (1 of 14). Twenty-nine patients had 69 parenchymal cysts. An attempt was made to assess the viability of these parenchymal lesions by matching the CT and MR findings with the Escobar pathologic staging system. Neuroimaging findings seemed compatible with early parenchymal lesions in the vesicular stage in 11 instances. Findings in cases with later stage cysts tend to support the concept that a dying larva provokes pronounced inflammatory reaction in the adjacent brain. Computed tomography remains the superior modality for depicting parenchymal calcifications within dead larvae. A case of a spinal cysticercosis cyst demonstrated with MR (in a patient with extensive intracranial cisternal cysts and a fourth ventricular cyst) is described.

Adolescent↗

PubMedDate not supplied

Lhermitte-Duclos disease: CT and MR findings.

The typical CT findings of Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum) are a hypodense nonenhancing unilateral posterior fossa mass, with or without adjacent occipital thinning, hydrocephalus, and calcification. Magnetic resonance (MR) has been found to be very helpful, and superior to CT, in delineating the margins of the lesion for determining the extent of surgical resection. Since recurrence is known, MR is important in the follow-up of these patients. To our knowledge this is the first reported case that included MR examination with administration of gadolinium. There was no enhancement of the lesion, consistent with previous reports of no contrast enhancement on CT.

Adult↗

PubMedDate not supplied

SPIR MRI in spinal diseases.

We report on our experience with the fat suppression technique of spectral presaturation with inversion recovery MR in imaging certain spinal disorders. This technique may assist in demonstrating or excluding the presence of fat within a lesion (such as lipoma, dermoid, teratoma) or within a normal structure (i.e., vertebral body or epidural space). The method can also be used to suppress normal fat (such as marrow or epidural fat) thus increasing the conspicuity of adjacent high signal intensity lesions seen on T1-weighted images (such as blood and contrast-enhancing tumors or inflammatory lesions).

Abscess↗