J. R. Jinkins

Prevalence of incidental intraspinal lipoma of the lumbosacral spine as determined by MRI

Study Design. The prevalence and appearance on MRI of lipomas of the filum terminale was studied in a random population referred to MRI for evaluation of the lumbosacral spine. The MRI scans of 100 patients selected at random were retrospectively reviewed. Objectives. The study sought to determine the frequency and MRI appearance of incidental filum lipomas in a random population. Summary of Background Data. Postmortem studies have reported a 4%-6% incidence of occult fibrolipmas of the filum terminale in what were thought to be otherwise normal spinal cords. The improved resolution of MRI imaging allows the detection of small amounts of fat associated with the filum terminale that heretofore had not been demonstrated on radiologic imaging examinations. Methods. The lumbosacral spine unenhanced MRI scans of 100 patients not previously operated upon were selected at random and were retrospectively reviewed by two of the authors (EB and JCM). Results. Of the 100 MRI examinations reviewed, four patients were found to have small lipomas of the filum terminale. No spinal dysraphism or cord tethering were present in these four patients. Their clinical symptoms were related to disc herniation in two patients, spinal stenosis in one, and discitis in one. The lipomatous tissue was hyperintense to cerebrospinal fluid (CSF) on T1-weighted images and hypointense to CSF on T2-weighted images. Conclusions. Incidental lipomas of the filum terminale were present in 4% of 100 lumbosacral spine MRI examinations in a random population.

MRI of radiation myelitis: a report of a case treated with hyperbaric oxygen.

Abstract. Radiation therapy is commonly applied as a primary or adjuvant therapy for malignancies. One of the major complications following radiation therapy is the necrosis of the otherwise normal surrounding soft tissues and/or bone. Post-radiation myelopathy rarely occurs when the spinal cord is included within the radiation field, in cases of high total radiation doses or for high radiation doses per fractionation. Up until the present, no tolerance dose for the spinal cord has accurately been defined and no treatment has proved satisfactory. Hyperbaric oxygen therapy is already currently used as adjuvant treatment for osteoradionecrosis and for radionecrosis of soft tissues with satisfactory results, whereas results for the treatment of post-attinic myelitis were contradictory. The aim of our report is to describe a case of radiation myelitis with a progressive improvement in the clinico-radiologic picture following hyperbaric oxygen treatment.

Subtotal agenesis of the cerebellum in an adult

We describe a 58-year-old asymptomatic woman with subtotal developmental absence of the cerebellum. MRI evaluation showed minute remnants of cerebellar tissue corresponding to the anterior quadrangular lobules. These findings identified the anomaly as subtotal cerebellar agenesis, and excluded other diagnostic possibilities.

Recognition of abnormalities on computed scout images in CT examinations of the head and spine

SummaryWe investigated the information which can be obtained from the computer-generated digital radiographs (“scout images”) performed for CT examinations. One hundred CT examinations of the head and one hundred of the spine were randomly selected and retrospectively reviewed: the head scout images were acquired in the lateral projection, and those of the spine in the lateral and/or anteroposterior projections. In 122 patients with demonstrable pathology on the CT sections or the scout image, a total of 154 abnormalities was found, of which 31 (20%) were identified only on the scout images. Eight (25.8% of this number) required additional clinico-radiologic study and were therefore designated as clinically pertinent positives. This study demonstrates that the CT scout image may contain considerable, clinically relevant information which is not available on, or is complementary to, the CT sections.

Ganglioglioma of the trigeminal nerve: MRI

Abstract Ganglioglioma of the cranial nerves is extremely rare; only a few cases involving the optic nerves have been reported. We present a case of ganglioglioma of the trigeminal nerve, which was isointense with the brain stem on all MRI sequences and showed no contrast enhancement.

Ruptured spinal dermoid cyst with chemical arachnoiditis and disseminated intracranial lipid droplets

A 33-year-old man presented with a 3-month history of gradually progressive leg weakness. Spinal MRI and myelography with CT demonstrated an extensive intradural abnormality suggesting a diffuse inflammatory or neoplastic process. Only after cranial CT and MRI demonstrated lipid droplets was the diagnosis of a ruptured spinal dermoid cyst suggested. Subsequent laminectomy revealed a ruptured intradural dermoid cyst in the lumbar spine, with chemical arachnoiditis.

Agenesis of a lumbar pedicle: MR demonstration

A 34-year old man complained of intermittent low back pain without radicular signs. Conventional radiographs showed asymmetry of the neural arch of L5. An M R study demonstra ted absence of the right 5th lumbar pedicle. Associated secondary changes included anomalous fusion of the transverse process of L5 to the body of L5 anterolateral to the normalpedic le position, bridging of the space left by the defect in the neural arch by the articulation of the inferior facet of L4 with an anomalous facet originating f rom the sacrum (possibly the superior facet of S1), and craniocaudalwidening of the neural foramen (Figs. 1, 2).

Peripheral vascular gunshot bullet embolus migration to the cerebral circulation : report and literature review

SummaryBullet embolization to intracranial branches of the major cerebral arteries is a rare complication of gunshot wounds. A review of the literature on cerebral vascular bullet embolization from peripheral sources revealed a number of single case reports that included 12 cases involving the anterior cerebral circulation, and one which involved the posterior circulation. This communication details two additional subjects who were treated at our institution.

The characteristics of cerebral meningiomas and surrounding tissues on dynamic CT

SummaryDynamic CT was utilized to evaluate 11 patients with histologically benign meningiomas. While it was found that all demonstrated macroscopic neovascularity, subtle differences in the dynamic perfusion curves were identified both between different meningiomas and from region to region within the same tumor. Other than basic anatomic differences, these changes may reflect intratumoral ischemia and hypothetically herald cystic/necrotic alteration within the neoplasm. The dynamic calculations over the surrounding brain showed areas of gross hyper- and hypoperfused cerebral cortex, and hypoperfused white matter in regions of peritumoral edema. These latter findings are of uncertain clinical importance. The dynamic examination also confirmed cases of dural venous sinus invasion and calvarial permeation by tumor. In addition, the dynamic series showed macroscopic neovascularity in one case with a completely negative selective cerebral arteriogram. It is felt that certain cases which have previously been evaluated by static CT may benefit from further study utilizing the dynamic method.

Subependymoma of filum terminale: MR appearance.

This report describes a subependymoma of the filum terminale evaluated by MRI. The mass demonstrated hyperintense signal on conventional spin echo T1-weighted, proton density, and T2-weighted imaging and nonenhancement after intravenous gadolinium administration. These characteristics distinguish this lesion from other more common neoplastic and inflammatory lesions arising in the lumbar spinal canal that are typically isointense on T1-weighted spin echo acquisitions, hyperintense on T2-weighted imaging, and enhance variably after intravenous gadolinium administration.