Measurement of viral sequences in cerebrospinal fluid of AIDS patients with cerebral white-matter lesions using polymerase chain reaction.

OBJECTIVES: To optimize the use of polymerase chain reaction (PCR) on cerebrospinal fluid (CSF) for the evaluation of central nervous system (CNS) white-matter lesions that along with clinical findings and magnetic resonance imaging (MRI) can allow a definite diagnosis to be made; also to evaluate treatment with zidovudine plus foscarnet. DESIGN AND METHODS: Fifteen AIDS patients with uncertain CNS white-matter lesions were identified. HIV-1 RNA, cytomegalovirus (CMV) and JC virus (JCV) DNA were measured in a total of 29 CSF samples. The results were correlated with clinical and MRI findings and treatment with zidovudine plus foscarnet was evaluated. RESULTS: Four and five out of 15 patients with CMV DNA > or = 1 : 625 and JCV DNA > or = 10(3) copies/microl detected in the CSF were diagnosed with CMV and progressive multifocal leukoencephalopathy (PML), respectively. Six patients who were CMV/JCV-negative with the highest levels of HIV RNA (median, 6.87 log10 copies/ml) in CSF were considered as having HIV-1 encephalitis. Neurological symptoms were non-supportive for diagnosis as was MRI in 11 out of 15 patients. Nine patients completed a 21-day course of zidovudine plus foscarnet. HIV RNA decreased irrespective of neurological diagnosis. All three HIV-1 encephalitis patients and two out of three patients with CMV leukoencephalopathy improved. In these two latter patients, relief of clinical symptoms coincided with decreased CMV DNA. JCV DNA remained unchanged and all three PML patients deteriorated. CONCLUSIONS: Measurement of CSF viral sequences supports the diagnosis of CNS white-matter lesions in AIDS patients. While effective therapy for PML remains elusive, treatment including zidovudine plus foscarnet may be a promising option for HIV-1 and CMV-related manifestations.

Localised 1H-MR spectroscopy for metabolic characterisation of diffuse and focal brain lesions in patients infected with HIV.

OBJECTIVES: To evaluate the role of proton MR spectroscopy (1H-MRS) in detecting metabolic changes in diffuse or focal lesions in the brain of patients infected with HIV. METHODS: Sixty HIV seropositive patients (25 with HIV related encephalopathies, 20 with toxoplasmosis, eight with progressive multifocal leukoencephalopathies (PMLs), and seven with lymphomas) and 22 HIV seronegative neurological controls were examined with a combined MRI and 1H-MRS technique using a Siemens 1.5 Tesla Magnetom. Spectra (Spin Echo sequence, TE 135 ms) were acquired by single voxel, localised on focal lesions in toxoplasmosis, PML, lymphomas, and HIV encephalopathies and on the centrum semiovale of neurological controls. Choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), lactate, and lipids were evaluated in each spectrum and NAA/Cr, NAA/Cho, and Cho/Cr ratios were calculated. RESULTS: A significant decrease in NAA/Cr and NAA/Cho ratios were found in all HIV diagnostic groups in comparison with neurological controls (p<0.003), suggesting neuronal or axonal damage independent of brain lesion aetiology. However, the NAA/Cr ratio was significantly lower in PML and lymphomas than in HIV encephalopathies (p<0.02) and toxoplasmosis (p<0.05). HIV encephalopathies, lymphomas, and toxoplasmosis showed a significant increase in the Cho/Cr ratio in comparison with neurological controls (p<0.03) without between group differences. The presence of a lipid signal was more frequent in lymphomas (71%) than in other HIV groups (Fisher's test, p=0.00003). The presence of mobile lipid resonance together with a high Cho/Cr ratio in lymphomas may be related to an increased membrane synthesis and turnover in tumour cells. A lactate signal (marker of inflammatory reaction), was found in all but one patient with PML lesions (75%), but had a lower incidence in the other HIV diagnostic groups (Fisher's test, p=0.00024). CONCLUSION: 1H-MRS shows a high sensitivity in detecting brain involvement in HIV related diseases, but a poor specificity in differential diagnosis of HIV brain lesions. Nevertheless, the homogeneous metabolic pattern that characterises PML suggests the usefulness of 1H-MRS as an adjunct to MRI in differentiating CNS white matter lesions, such as HIV encephalopathies, from PML.

Rationale for the use of contrast media in MR imaging.

Understanding the rationale of contrast media use in MR imaging is based on knowledge of the blood brain barrier (BBB) and the pathophysiology of infectious agents attacking the central nervous system. This article focuses on the relationship between BBB structures and functions in healthy and unhealthy conditions and contrast media in patients with acquired immunodeficiency syndrome.

CNS cryptococcosis in AIDS: spectrum of MR findings.

Cryptococcus is a ubiquitous saprophytic fungus that may become pathogenic, particularly in immunosuppressed patients. In the CNS of AIDS patients, the incidence of this fungal infection is 5% of all the opportunistic infections. In this study, we review the MR findings in nine AIDS patients affected by CNS cryptococcosis. All MR studies were performed before and after intravenous administration of a single dose of gadopentetate dimeglumine and again after an additional dose. Autopsy was performed in one case. Magnetic resonance imaging revealed evidence of meningitis or meningoencephalitis, dilated Virchow-Robin spaces, cyst-like structures (gelatinous pseudocysts), and granulomas (cryptococcomas) of the choroid plexuses. The last two findings (pseudocysts and choroidal ependymal granulomas) are relatively specific for cryptococcosis.

[Lymph nodes of the neck. Diagnosis using magnetic resonance with gradient-echo technique]. / I linfonodi del collo. Diagnosi mediante risonanza magnetica con tecniche a eco di gradiente.

As for the pathologic conditions of neck lymph nodes, the clinician needs to know if the involved node is reactive, phlogistic, or neoplastic in nature. If accurate tumor staging is required, imaging techniques play a fundamental role. Our study was aimed at assessing the actual role of MR imaging in the evaluation of neck lymph node involvement. The study was performed using an MR Max Plus by General Electrics operating with an 0.5 T superconductive magnet. We employed gradient-echo (GE) pulse sequences with TR 500, TE 15 ms and 90 degrees flip angle for T1-weighted images, and with TR 500, TE 30 ms and 25-30 degrees flip angles for T2-weighted images; for Pd-T2-weighted images, TR was 520, TE 30 ms, and flip angles were 40-45 degrees. The results were correlated with histopathologic findings obtained at biopsy. The advantages of GE sequences were: 1) whole neck imaging--thus saving time, and reducing radiation dose and contrast media; 2) optimal anatomical and topographic evaluation of the lesion; 3) imaging of the longitudinal diameter of the node; 4) higher sensitivity for lymph node tissue modifications; 5) imaging of necrosis, hemorrhage, and/or fibrosis. GE sequences were especially useful for accurate tumor staging, in the follow-up, and to verify response to therapy. However, even though MR imaging has proven to have high sensitivity, its specificity was similar to that of contrast-enhanced CT. Further studies with the use of paramagnetic contrast media are needed to solve these problems.

[Neuro-AIDS: a multicenter neuroradiological study]. / Neuro-AIDS: studio neuroradiologico multicentrico.

The results are described of a retrospective multicentric CT/MR study of 141 neuro-AIDS patients (IV group CDC classification); 114 patients were drug addicted, 13 homosexual, 8 polytransfused, and 6 had other risk factors. The mean age was 29.6 years. The pathologic agent was identified in 47 cases by c.s. fluid examination, biopsy, autopsy or specific treatment response: it was HIV in 20 cases, toxoplasmosis in 11, cryptococcosis in 9, leishmaniasis, salmonella and papovavirus in single cases. In the follow up of 2 cases, a Kaposi's sarcoma and a primitive CNS lymphoma occurred. The main clinical features were AIDS-dementia complex (45% of cases) and focal neurologic manifestations (36%). The neuroradiological protocol consisted of 238 CT exams (97 controls), most of them with DDD (delayed double dose) technique, 7 MR exams (0.15 T) and 2 angiographies. CT findings were divided into 3 groups: negative (16%), atrophic (47%) and focal lesions (37%). In the first and second group, HIV and cryptococcal infections were the main pathologic agents. In the third group toxoplasma infections were discovered, and TB granulomas and other pathologic conditions, with ring-like or nodular enhancement, in cortical/cortico-medullary location. In follow-up patients a high tendency of evolution towards focal lesions was observed, even in negative cases. The DDD enhancement technique allowed in most cases both the demonstration of very small lesions and their grading. According to the literature CT, though a highly sensitive method, is inferior to MR imaging; however our experience in this field is currently insufficient. The specific diagnosis of pathologic agents of neuro-AIDS is difficult, due to the high number of opportunistic AIDS-related infections and neoplasms, with overlapping features: differential diagnostic criteria can be assessed only by comparing the clinical, microbiological, topographic, CT and MR findings. CT and MR exams are necessary to guide and monitor therapy and to plan stereotaxis biopsy.

[Ambulatory radicular myelography with iopamidol]. / Radicolomielografia ambulatoriale con Iopamidolo.

The appearance of side effects was monitored in 70 selected patients who underwent radiculography and myelography. After the examination, a rapid return to normal activity was recommended. In accordance with literature, no greater incidence of side effects was found in patients who were allowed to get up soon after myelography or radiculography, than in patients confined to bed for some hours. These results are essentially attributable to the low toxicity of the contrast medium used in this study (Iopamidol), and to an adequate hydratation of the patients after examination.

Clinical and CT parameters in degenerative cerebellar atrophy in aged patients.

Fifteen cases of degenerative cerebellar atrophy are presented together with the criteria used to assess the diagnosis of cerebellar atrophy by computed tomography.

[Fenestration of the extracranial tract of the vertebral artery: angiographic demonstration of 3 cases]. / Fenestrazione del tratto extracranico dell'arteria vertebrale: dimostrazione angiografica di 3 casi.

The authors describe 3 cases of the extracranial Vertebral artery fenestration. This anomaly is a rare case seen in autopsy and angiographically, and in literature too the cases described are few and prevalently by Japanese authors. This anomaly is important because frequently is associated with others congenital intra and extracranial vascular abnormalities.

Double fenestration of the extracranial vertebral artery.

This is a case report of an angiographically demonstrated double fenestration of the extracranial vertebral artery found at the same level.