Biomedical subjects
Publications and source records attributed to Robert A Koenigsberg.
Two cases of lumbar dural ectasia secondary to spinal fusion are presented. Background history of dural ectasia is discussed; computed tomography (CT) and MR imaging characteristics of dural ectasia are shown and possible causes are discussed.
A 54-year-old woman presented for cardiac evaluation of atypical chest pain. Workup included coronary angiography and a left ventriculogram, during which air was inadvertently injected, resulting in the development of an acute right hemisphere syndrome. Right carotid angiography was immediately performed, yielding only a delayed diffuse venous phase without focal vessel cutoffs. Within 60 minutes, the patient underwent hyperbaric oxygen therapy for the suspected cerebral air emboli. After removal from the chamber for technical reasons, she had a generalized tonic-clonic seizure, and further hyperbaric oxygen therapy was withheld. Initial computed tomography imaging obtained approximately 8 hours after symptom onset showed signs of early right hemispheric edema. Subsequent magnetic resonance imaging studies were markedly abnormal and suggestive of diffuse bilateral but predominantly right-sided parietal lobe edema with mildly positive diffusion-weighted imaging. Follow-up magnetic resonance imaging at 6 months was normal, and the patient's neurological examination returned to normal.
BACKGROUND AND PURPOSE: Platybasia, or abnormal obtuseness of the basal angle, was first measured on plain skull images. At present, evaluation of the brain and skull more commonly involves CT and MR imaging. We evaluated a new MR imaging method of evaluating platybasia. METHODS: We retrospectively evaluated midline sagittal MR images in 200 adults and 50 children. The basal angle of the skull base was measured by using two methods: The standard MR imaging technique measured the angle formed by two lines-one joining the nasion and the center of the pituitary fossa connected by a line joining the anterior border of the foramen magnum and center of the pituitary fossa. The modified technique measured the angle formed by a line across the anterior cranial fossa and dorsum sellae connecting a line along the clivus. RESULTS: With the standard MR imaging technique, we obtained mean angles of 129 degrees +/- 6 degrees for adults and 127 degrees +/- 5 degrees for children, compared with 135.3 degrees (composite mean) in previous series. The modified technique produced values of 117 degrees +/- 6 degrees for adults and 114 degrees +/- 5 degrees for children, which were significantly lower that those of standard MR imaging and traditional radiography (P <.05). CONCLUSION: Both the standard and modified MR imaging techniques produced basal angles lower than those previously reported with standard radiography. The modified technique uses clearly featured landmarks that can be reproduced consistently on midline sagittal T1 images. This technique and its corresponding values can be used as the new standard for evaluating the basal angle.
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Anomalies of the vertebral arteries are uncommon, but important to recognize in the diagnosis and catheter based evaluation and treatment of patients suffering cerebrovascular disease. This article illustrates our experience with such anomalies. These include the vertebral artery arising as the fourth and most distal branch of the aortic arch, as a right subclavian artery branch arising distal to the right thyrocervical trunk, as a right common carotid artery branch in a patient with an aberrant right subclavian artery, and a case of left vertebral artery proximal duplication, with both aortic and left subclavian vertebral arteries present in the same patient; the latter join to form a single distal cervical vertebral artery.
BACKGROUND: The posterior inferior cerebellar arteries (PICA) arise from the intracranial segments of the vertebral artery (VA). We report a case where a nondominant isolated vertebral artery, which terminated in PICA, was stenotic. This resulted in brainstem-lower cerebellar ischemia, corrected with balloon angioplasty. CASE DESCRIPTION: A 62-year-old male presented primarily with transient vertigo, syncope, and dizziness and was diagnosed with transient ischemic attack. Angiography of the left vertebral artery (VA) demonstrated a small-caliber vessel terminating in PICA with a 90% stenosis at the C6 level. Angioplasty of the left VA was performed with excellent resolution of the stenosis. CONCLUSIONS: This case illustrates cerebellar insufficiency in a unique case where the PICA was isolated, supplied by a small- caliber VA. Correction of the stenosis improved the patient's symptomatology and prevented an inferior brainstem-cerebellar infarction.
The authors present an unusual case of a young male patient with a large left common carotid artery pseudoaneurysm in a shape similar to that of a bowtie treated with a covered Wallgraft. The Wallgraft is a covered stent originally designed to be used in the treatment of tracheobronchial fistula and peripheral arterial applications. The favorable outcome of this case illustrates its endovascular application in nonsurgical traumatic injuries of the carotid artery.
BACKGROUND AND PURPOSE: In patients with multiple sclerosis (MS), a few preliminary functional MR (fMR) imaging studies of the visual cortex reveal information about magnitude differences between healthy individuals and patients with MS at only a single luminance level. We therefore investigated whether varying luminance contrast levels can help uncover subtle changes in fMR imaging characteristics of the visual cortex in healthy volunteers and patients with MS. METHODS: Blood oxygenation level-dependent fMR imaging signal changes in the primary visual cortex were examined as a function of luminance contrast at 1.5 T in 10 healthy volunteers and nine patients with MS. Ten axial sections through the calcarine fissure were obtained with an echo-planar T2*-weighted imaging sequence (4000/54/1 [TR/TE/excitation]; field of view, 220 mm; voxel size, 1.72 x 1.72 x 5 mm). The imaging series consisted of an alternating 20-second rest epoch (black screen) with a 20-second activation epoch (flickering checkerboard) repeated six times. Each imaging series used a graded increase of eight luminance contrast levels. A paired t test between rest and activation images was used to analyze significant (P <.001) contiguous voxels in the region of interest (primary visual cortex). RESULTS: A progressive increase in fMR imaging activation across all luminance contrast levels in healthy controls and patients with MS was shown. The patients with MS had a significantly lower magnitude in the number of fMR imaging activated voxels at all luminance contrast levels (P <.001). A statistically significant increase in fMR imaging activation (activation threshold) was seen at the second luminance contrast level in controls and at the seventh level in patients with MS. CONCLUSION: Quantifiable changes in blood oxygenation level-dependent signal and a progressive increase in activated voxels within the primary visual cortex with increasing luminance contrast were demonstrated at 1.5 T in controls. The patients with MS showed a significant decrease in the number of activated voxels and an increase in activation threshold compared with healthy controls.
We present an unusual case of a primary lumbar disk-space mass that presumably developed secondary to a chronic hyperextension spinal fracture associated with spinal stenosis. This injury resulted in the appearance of a lumbar intervertebral disk-space mass or pseudotumor. The pseudotumor most likely resulted from a prior spinal fracture, leading to a fused hyperextension deformity in a patient with underlying chronic degenerative spinal disease.