Nuclear medicine applications to the neuroimaging of AIDS. A neuroradiologist's perspective

The human immunodeficiency virus (HIV) responsible for AIDS is reaching epidemic proportions in the United States and Europe. As new therapeutic modalities against HIV are uncovered and applied to treat prophylactically asymptomatic and therapeutically symptomatic HIV positive patients, imaging studies are no longer used just to characterize the organic-morphologic effects of HIV and opportunistic infections and neoplasms. This article discusses the current applications and contribution of nuclear medicine to the management of neurologically symptomatic HIV-positive patients.

Inflammatory and infectious processes of the cervical spine

This article discusses infectious and inflammatory processes of the cervical spine. Major emphasis is placed on infectious discitis/osteomyelitis and epidural abscess, particularly the epidemiologic, bacteriologic, pathophysiologic, and clinical aspects, as well as the major role played by magnetic resonance imaging and other imaging modalities used in the detection and diagnosis of these processes.

A pilot clinical and pharmacological study of intra-arterial infusion of thiotepa

Fourteen patients with progressive localized tumors were treated on a clinical and pharmacological study with intra-arterial Thiotepa. A transfemoral percutaneous catheter was inserted into the major artery supplying the tumor. A venous catheter was inserted into the vein draining the tumor area for blood sampling. Doses of Thiotepa ranged from 0.3 mg/kg to 1.0 mg/kg. Courses were repeated monthly and doses of drug escalated as tolerated. Toxicity was mild and doses of drug at least up to 0.9-1.0 mg/kg were tolerable. Pharmacokinetic parameters suggest increasing binding of Thiotepa to tissue when the drug is administered by the intra-arterial route. Clinical responses were observed in a patient with melanoma and in another patient with unknown primary cancer.

A pilot clinical and pharmacokinetic study of intracarotid cisplatin and bleomycin

Fifteen patients with progressive primary malignant or metastatic brain tumors were treated on a clinical and pharmacokinetic study with intracarotid cisplatin and bleomycin. Toxicity was tolerable and consisted mainly of nausea and vomiting. Neurologic toxicity included focal seizures (1), leukoencephalopathy (1), and motor weakness (1). Five patients had improvement in CT scans and four patients had stabilization of disease. Recommended dosage for future clinical trials are cisplatin 60 mg/m2 and bleomycin 100 units. Pharmacokinetics of intracarotid cisplatin revealed the jugular vein concentration was twice the peripheral vein level at the end of infusion. Cisplatin is a drug which has demonstrated in vitro activity against malignant gliomas (1). Clinical trials with intravenous administration of cisplatin has shown definite, although limited antitumor activity against primary brain tumors (2,3,4) and metastatic brain tumors (5,6). To enhance its antitumor effect, cisplatin has been administered by the intracarotid route (7,8,9). The results appear encouraging, but neurological and ophthalmological toxicity may occur (8). In our initial study with intracarotid cisplatin, 35 patients with malignant brain tumors (23 with primary brain tumors and 12 with brain metastases) progressing after cranial irradiation +/- chemotherapy were treated. Of 20 evaluable patients with primary tumors, 6 responded to therapy and 5 had stable disease. Five of 10 evaluable patients with brain metastases responded and 2 had stable disease. For responding primary brain tumor patients the median time to progression was 33 weeks. The recommended dose for intracarotid cisplatin was 60-75 mg/m2 administered every 3-4 weeks (7,8). Higher cisplatin doses produced more central neurological toxicity. There is limited data on the central nervous system pharmacology of cisplatin.(ABSTRACT TRUNCATED AT 250 WORDS)

Herpes simplex virus type 1. A cause of the acute retinal necrosis syndrome

The authors have isolated herpes simplex virus type 1 (HSV-1) from the vitreous of two patients with acute retinal necrosis. Clinical and laboratory data suggest that one case represented a primary HSV-1 infection, whereas the other case appeared to be a recurrent HSV-1 infection. In the primary case, changes on magnetic resonance imaging (MRI) suggest spread of the virus posteriorly to both optic tracts and the lateral geniculate ganglia. This case shares many features with the "von Szily" experimental model for HSV retinitis in the mouse.

Ototoxicity of low- and moderate-dose cisplatin

Twenty-four patients with head and neck neoplasms were prospectively evaluated for cisplatin (DDP)-induced ototoxicity. Patients were selected from a larger population based on the uniformity of their chemotherapy regimen, renal status, lack of prior or concurrent exposure to ototoxic agents, and availability for repetitive audiometric testing in the same setting. Scanning electron microscopy of the inner ear was performed on four temporal bones. Hearing impairment was found to be dose-related, irreversible within the confines of the study period, and primarily in the higher frequencies. Vestibular toxicity was rare and well-documented by our testing methods in only one patient. Based on the results of this study, and a review of animal and human data on DDP ototoxicity, the authors concluded that ototoxic screening should be reserved for patients defined as "at risk" and those patients receiving more than 400 mg of DDP under the conditions stated in this report.

Computed tomography of nontuberculous spinal infection

The CT findings in 16 patients with nontuberculous spinal infections were reviewed. The specificity of certain CT features as well as the usefulness of intravenous contrast medium administration are discussed. The associated clinical presentations and predisposing factors are outlined. Emphasis is placed on a combined clinical, radiographic approach in facilitating an early diagnosis.

Computed tomography of spinal tuberculosis

The computed tomographic (CT) features of nine documented cases of spinal tuberculosis are analyzed. The mechanisms of vertebral involvement are reviewed. The ability of CT to facilitate the diagnosis as well as to delineate the extent of soft tissue involvement is emphasized. The need for increased alertness to the diagnosis of tuberculosis is stressed.

Cis-platinum vestibular toxicity

Cis-diamminedichloroplatinum has been proven to be an effective neoplastic agent. Nephrotoxicity and ototoxicity are two prominent side effects of this drug. Investigation of ototoxicity has been limited to auditory function. This report details the first known case of vestibular toxicity following platinum therapy. In addition, a prospective vestibular testing program is reported.

Improved technique for cervical metrizamide myelography

Introduction of metrizamide into the lumbar subarachnoid space with the patient in a prone 15-20 degree head-down position improves delivery of contrast material for cervical myelography. Excellent visualization of the spinal cord and nerve roots has resulted using this technique.

Bilateral optic canal meningiomas: a case report

In the case presented, bilateral optic canal meningiomas produced binocular visual loss. Correct diagnosis was delayed because of inadequate and misinterpreted radiological studies. Careful radiological and surgical examination of the planum sphenoidale later suggested this as the source of both canalicular masses. The pertinent aspects of this case are reviewed in relation to information from similar cases reported previously. In the future, increased clinical suspicion and more accurate neuroradiological studies should improve the detection and afford earlier surgical treatment of meningiomas of the optic canal.

Meningiomas and aneurysms of the cavernous sinus. Neuro-ophthalmologic features

A series of 16 patients with unilateral ophthalmoplegia due to mass lesions of the cavernous sinus was analyzed; there were six cavernous meninglomas and nine intracavernous aneurysms. All meningiomas were characterized by painless, insidiously progressive partial nerve palsies, as were half of the aneurysms; the remaining aneurysm patients experienced acute painful episodes. Pharmacologic pupillary tests failed to confirm a coexisting Horner syndrome in the majority of cases with anisocoria. Although plain skull films were unremarkable or misinterpreted as normal, bone tomograms, computerized axial tomograms, radionuclide scans, and cerebral angiograms established the diagnosis in all cases. Because cavernous meningiomas show slow progression and are surgically inaccessible, craniotomy is advised only if the visual pathways or brain stem is compromised. Intractable pain appears to be the only distinct indication for intervention with cavernous aneurysms.