Biomedical subjects
Publications and source records attributed to D Enzmann.
Perfluorohexylbromide, a nonionic and biologically inert radiodense compound, was evaluated as a potential contrast agent. Pulmonary and gastrointestinal administration of the neat liquid form was tested in dogs in conjunction with computed tomographic body scans. Contrast enhancement was demonstrable in one organ, the spleen, within 6 hr of gastrointestinal administration of perfluorohexylbromide.
The computed tomographic appearance and the differential diagnosis in a case of unusual congenital intraventricular arachnoid cyst are presented.
Rabbits with thigh abscesses received an intravenous solution of polyvinylpyrrolidone (PVP) and metallic salts, resulting in a dense ring of contrast enhancement as determined by computed tomography (CT). Enhancement increased during the first two weeks, stabilized, then decreased to control levels at eight weeks. After antibiotics the ring of enhancement appeared to mark the abscess perimeter as it regressed. Normal muscle density did not change. The magnitude and duration of enhancement would improve CT detection of small lesions and be useful in evaluating the efficacy of therapy.
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system which predominantly affects immunologically compromised hosts. The distinctive CT appearance in three documented cases includes low-density lesions of central and convolutional white matter with scalloped lateral borders. Lesions demonstrate no mass effect or contrast material enhancement. Findings are discussed with reference to other entities which may produce a similar CT appearance.
Two cases of giant-cell arteritis with cerebral arteritis are presented. The clinical situation and the suggestive but nonspecific angiographic features make the antemortem diagnosis possible. Greater awareness of this entity will facilitate its diagnosis and the institution of effective steroid therapy.
A classical "watershed" infarction pattern on brain scintigraphy was demonstrated in a seven-year-old black girl with sickle cell disease. Computed tomography (CT) showed minimal abnormalities compared to the characteristic findings on the radionuclide image.
The CT scan with the 160 x 160 matrix demonstrated both the normal orbital anatomy and the abnormal orbital anatomy of Graves' ophthalmopathy in great detail. In Graves' ophthalmopathy, the cardinal pathologic feature of extraocular muscle enlargement was accurately reflected on the CT scan and was a distinctive, diagnostically reliable finding. Enlargement of the medial and lateral rectus muscles and of the apex of the muscle cone were the most consistent findings. The severity of the CT scan abnormalities correlated well with clinical severity. Because muscle cone abnormality was observed characteristically in those patients with sight loss, we suggest that pressure by the extraocular muscles on the optic nerve may contribute to visual acuity loss in this disease.
CT scans of 9 patients with orbital pseudotumor (bilateral in 6 and unilateral in 3) showed findings distinct from those observed in Graves' ophthalmopathy. In bilateral involvement, they ranged from localized mass lesions to complete obiliteration of normal orbital CT anatomical landmarks; diffuse or multifocal lesions involving the posterior globe and muscle insertions were most typical of the diagnosis. However, findings in unilateral psedotumor may be indistinguishable from orbital mass lesions other than Graves' ophthalmopathy. Serial CT scans were used to show progression of disease and response to treatment.
The CT findings in neonatal herpes simplex encephalitis (HSE) type II have been previously described, whereas magnetic resonance (MR) findings as yet have not. Early CT findings can be subtle and difficult to detect. However, as the abnormalities evolve, most notably the strikingly increased density of cortical gray matter, they appear highly characteristic of neonatal HSE type II. This case report with neuropathologic verification describes serial MR and CT findings in HSE type II that suggest an etiology of the increased density characteristically seen on CT scans; it does not appear to be hemorrhage or calcification.
A murine model of implanted CNS neoplasia was used to study a new form of brain tumor immunotherapy with intralesional Corynebacterium parvum (C. parvum). Assessment of treatment protocols has been limited by the inability to assess, noninvasively, tumor burden and/or the inflammatory reaction induced in the murine brain by treatment with C. parvum. This study demonstrates that contrast-enhanced MR imaging can monitor in vivo tumor burden and the immune response to intracerebral C. parvum. KHT murine sarcoma was stereotaxically implanted into the right frontal lobe of C3H/HeN mice at doses of 10,000 and 50,000 tumor cells. The KHT sarcoma is 100% fatal in untreated mice. Therapy consisted of an intraperitoneal injection of 350 micrograms of killed C. parvum 1 day after tumor implantation followed by 70 micrograms of C. parvum stereotaxically injected into the tumor 5 days after implantation. MR imaging was performed on mice injected with saline only, C parvum only, tumor only, and tumor treated with C. parvum. C. parvum alone elicited an intense transitory mononuclear cell inflammatory reaction in the meninges, ependyma, and to a variable degree at the injection site. The inflammatory response reached a peak 2 weeks after intracerebral injection. Contrast-enhanced MR imaging was able to detect the presence and severity of C. parvum-induced inflammation, which decreased 3 weeks after intracerebral injection. The transitory nature of this type of inflammation should allow its differentiation from tumor in subjects undergoing serial scanning following intracerebral injection of C. parvum as a form of brain tumor immunotherapy.
MR images of 14 patients with pyogenic and three patients with tuberculous infectious spondylitis were studied to develop criteria for diagnosis. T1-weighted scans, 800/20 (TR/TE), were obtained in 17 patients and T2-weighted scans, greater than 2000/30,80, were obtained in 14. In seven patients, T2*-weighted scans (gradient-recalled acquisition into steady state, 25/15/5-7 degrees [TR/TE/flip angle]) and short-T1 inversion-recovery scans (STIR), 1400/150/40 (TR/TI/TE), as well as fat and water images (using a suppression technique), were obtained. Unenhanced and gadopentetate-dimeglumine-enhanced scans were obtained in four patients. In all but two patients with pyogenic infectious spondylitis, the T1-weighted sagittal scan showed characteristic findings: narrowed disk space, low signal intensity in the marrow of at least two adjacent vertebrae, subligamentous or epidural soft-tissue masses, and erosion of cortical bone. In one patient the T1-weighted scan was normal and abnormalities could be detected only on the T2-weighted scan. The remaining patient had abnormal marrow signal on the T1-weighted scan but only in one vertebral body. On T2-weighted images the major findings were a narrowed disk space with variable signal changes, abnormal high signal in marrow of at least two adjacent vertebrae, high-signal subligamentous or epidural masses, and cortical bone erosion. The findings in the three patients with tuberculous spondylitis included areas of increased and decreased signal intensity in vertebrae on T1-weighted images. Disk spaces were relatively spared given the extent of disease. Extraosseous soft-tissue components could be large. Bone erosion was best seen on the first echo of a T2-weighted sequence and on a water image; the latter was most reliable since it had no chemical-shift artifact. The use of gadopentetate dimeglumine could obscure or clarify MR findings, depending on the situation. T1- and T2-weighted MR images should be obtained for assessment of infectious spondylitis. STIR scans are particularly helpful. Fat images can be useful in subtle presentations, since they are very sensitive to marrow replacement, and gadopentetate dimeglumine may be helpful for epidural delineation of disease.
A rare, cytoplasmically inherited striatal degeneration associated with Leber's optic atrophy exhibited selective symmetric low-density lesions in the putamen on the CT scan in five patients. The CT findings, however, were asymmetric (one patient) and subtle in the early phases of the disease. Occasionally, caudate lesions were demonstrable. On MR imaging, the lesions had high signal intensity on T2-weighted images and low signal intensity on T1-weighted images. This group of patients was distinguished from patients with other causes of striatal degeneration by a lack of hemispheric, brainstem, or cerebellar atrophy.
Four patients with expansile cystic lesions of the petrous bone had correlative CT and MR scans. Characteristic findings were noted on MR scans obtained with T1- (TR = 400-800, TE = 25-32) and T2- (TR = 2000-3000, TE = 64-80) weighted images. These findings include an expansile cystic lesion centered in the petrous apex with high signal intensity on both the T1- and T2-weighted images, compatible with subacute or chronic hemorrhage. This signal pattern is distinct from the typical intradural epidermoid tumor, which has signal intensities similar to CSF with low signal on T1-weighted images and high signal on T2-weighted images. Surgical exploration yielded similar findings of a cyst containing free-flowing, brown watery fluid. Histologically, an inflammatory response was present as well as a variable number of cholesterol crystals. There was little identifiable capsular tissue but abundant evidence of subacute or chronic hematoma. The nomenclature of the etiology in these four cases is currently in some controversy, with some authors classifying these lesions as epidermoid or primary cholesteatomas while others call them cholesterol granulomas or giant cholesterol cysts. Whatever they are named, the MR image pattern is consistent and is dominated by findings indicative of hemoglobin breakdown products.