Neuroimaging in various stages of human immunodeficiency virus infection.
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AIDS-Related Complex↗
Biomedical subjects
M J Post
Publications and source records attributed to M J Post.
Effects of milrinone and salbutamol on antigen induced arachidonic acid metabolism in the isolated rat lung.
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Airway Resistance↗
In vivo anaphylaxis in the rat: effects of phosphodiesterase inhibitors.
On the basis of their inhibitory capacities on the phosphodiesterase enzyme system, we studied the anti-anaphylactic effect of milrinone and sulmazole in comparison with theophylline. For this purpose anaphylactic shock was induced in actively sensitised, spontaneously breathing rats. Milrinone, sulmazole and theophylline reduced anaphylactic bronchoconstriction without affecting the antigen induced fall in blood pressure. Surprisingly, sulmazole reduced mortality significantly.
Anaphylaxis↗
Anti-allergic effects of milrinone and sulmazole in isolated rat lungs in comparison with theophylline.
Milrinone and sulmazole, two recently developed drugs, inhibit specific fractions of the phosphodiesterase (PDE) isozyme system. Since theophylline aspecifically inhibits the PDE complex, we compared the effects of milrinone and sulmazole with those of theophylline on antigen-induced bronchoconstriction, vasoconstriction, mediator release and leukotriene production. In the isolated perfused and ventilated lung of actively sensitized rats, we elicited antigen-induced bronchoconstriction, vasoconstriction and release of mediators like histamine, 5-hydroxytryptamine (5-HT) and slow-reacting substance of anaphylaxis (SRS-A). Milrinone, sulmazole and theophylline inhibited antigen-induced bronchoconstriction and vasoconstriction in a dose-dependent manner with minor differences in potency. Antigen-induced release of preformed mediators like histamine and 5-HT was inhibited only at high concentrations of milrinone, whereas sulmazole failed to inhibit mediator release. Theophylline also failed to inhibit 5-HT release. However, SRS-A synthesis was markedly reduced by these drugs in relatively low concentrations. It is concluded that milrinone and sulmazole have anti-allergic effects similar to those of theophylline and that all three PDE inhibitors reduce SRS-A synthesis.
Airway Resistance↗
Comparison of the anti-anaphylactic effects of milrinone, sulmazole and theophylline in the rat.
Milrinone and sulmazole, two recently developed cardiotonic drugs, inhibit specific fractions of the phosphodiesterase (PDE) isozyme system, while theophylline inhibits the PDE complex aspecifically. Since these drugs were shown to have anti-allergic effects in isolated lungs, we wanted to study milrinone and sulmazole in comparison with theophylline in an in vivo model of anaphylaxis. For this purpose, actively sensitized rats were intravenously challenged with antigen, while tracheal pressure, oesophageal pressure, blood pressure and airflow were continuously monitored. Antigen challenge induced a transient bronchoconstriction and a persistent fall in blood pressure until death occurred. Anaphylactic shock was consistently followed by metabolic acidosis. Milrinone, 3 mg/kg, and theophylline, 40 mg/kg (but not 10 mg/kg), reduced anaphylactic bronchoconstriction. Sulmazole, 40 mg/kg, almost abolished bronchoconstriction. Although milrinone, sulmazole and theophylline, 40 mg/kg, caused a fall in blood pressure prior to antigen challenge, total fall in blood pressure (drug-induced and antigen-induced) was not affected by these drugs. Surprisingly, sulmazole reduced mortality significantly. This phenomenon is probably related to the less severe metabolic acidosis in the presence of sulmazole.
Acid-Base Equilibrium↗
Multifocal fibrosclerosis with hypertrophic intracranial pachymeningitis.
We describe a 34-year-old man with a 17-year history of multifocal fibrosclerosis resulting in unique neurologic complications. Episcleritis, orbital pseudotumor, and sclerosing cholangitis accompanied a florid intracranial inflammatory pachymeningitis. The latter was associated with blindness, multiple cranial neuropathies, pseudotumor cerebri, and seizures. Extensive investigation failed to reveal an etiology. Corticosteroids were ineffective in preventing progression of the disorder, and the value of antineoplastic therapy was uncertain. Multifocal fibrosclerosis, a rare disorder, may result in a confusing array of neurologic manifestations.
Adult↗
MR imaging of intracranial carotid occlusion.
The MR scans of seven patients with intracranial carotid occlusion (five proved, two presumed) were reviewed to evaluate the MR signal characteristics seen in this disorder. Five patients had clinical signs of cerebral infarction. Of the remaining two patients, one was asymptomatic and the other had a long-standing occlusion and headaches. We correlated the MR findings with cerebral angiography in five patients and with CT scans in six patients. All occluded vessels demonstrated MR signal predominantly isointense to brain on proton-density- T1- and T2-weighted images. Since there is an absence of flow, the MR signal is based on the intrinsic properties of the arterial thrombus and possibly on the chronicity of the occlusion. The pathogenesis and histopathology of intravascular thrombus differ significantly from extravascular hematoma, which accounts for the differences in their MR signal characteristics. The demonstration of occluded intracranial vessels may solidify the diagnosis of stroke in cases in which clinical and/or CT findings are equivocal. In patients presenting with infarction, an occluded carotid artery by MR may obviate the need for angiography; however, the demonstration of a patent carotid in conjunction with infarction suggests the possibility of an embolus, which may require angiography. We believe that MR is a valuable adjunct to CT in evaluating patients with cerebrovascular infarction.
Adult↗
Acquired spinal subarachnoid cysts: evaluation with MR, CT myelography, and intraoperative sonography.
Fifteen patients with acquired spinal subarachnoid cysts (14 surgically proved, one presumed) were evaluated preoperatively with immediate and/or delayed CT myelography (seven patients), MR (11 patients), or both (three patients). CT myelography separated subarachnoid cyst from myelomalacia and/or intramedullary cysts in four cases but failed to diagnose them in three, while MR accurately diagnosed subarachnoid cyst in all 10 cases that were also surgically proved. The results of these preoperative examinations were evaluated to determine the efficacy of each study in diagnosing subarachnoid cysts, ascertaining their extent and internal architecture, and detecting associated abnormalities of the spinal cord. In addition, during surgery these cysts were studied with sonography to gain an understanding of the pathophysiological mechanisms involved in their formation and propagation and to guide the surgeon in their decompression. On the basis of our experience, MR appears to be the most efficient preoperative study in diagnosing and characterizing acquired subarachnoid cyst and associated abnormalities. Intraoperative sonography provides a reliable means of ensuring adequate decompression of these cysts.
Adult↗
Tuberous sclerosis: characteristics at CT and MR imaging.
Computed tomography (CT) and magnetic resonance (MR) imaging findings were reviewed in 26 patients with tuberous sclerosis. All patients underwent CT; 16 patients underwent both. The CT features included subependymal nodules in 25 of 26 patients (96%) and calcifications in 23 of 26 (88%). Parenchymal hamartomas (cortical tubers) were seen in 23 of 26 patients (88%). These lesions had less attenuation than surrounding brain in 16 of 26 patients (62%) and were calcified in 14 of 26 patients (54%). Contrast enhancement of a lesion, indicating a subependymal giant cell astrocytoma, occurred in three of 26 patients (12%). The MR imaging characteristics included subependymal nodules (periventricular nodules) of intermediate signal intensity in ten of the 16 patients (63%). Parenchymal hamartomas, demonstrated in 15 of the 16 patients (94%), usually exhibited long T1 and T2 relaxation characteristics. The pattern was noted to be reversed in the two newborn patients (13%). One parent demonstrated a forme fruste at CT but had a normal MR image.
Adolescent↗
Spinal infection: evaluation with MR imaging and intraoperative US.
Magnetic resonance (MR) images of the spine and/or intraoperative spinal ultrasound (US) in 24 patients with spinal infections were reviewed and correlated with clinical and pathologic data to determine their diagnostic value. In disk space infection with osteomyelitis and in retrospinal abscess, MR images showed characteristic findings, whereas in myelitis, MR images demonstrated nonspecific abnormalities. The appearance on MR images of epidural abscesses ranged from clearly identifiable extradural masses with high-intensity signal on spin-echo T2-weighted images to extensive inhomogeneous collections of mixed signal intensities, difficult to distinguish from adjacent meningitis. Myelography with high-resolution computed tomography (CT) and intraoperative spinal US was superior to MR imaging in demonstrating epidural abscesses when there was concomitant meningitis. With intraoperative spinal US, epidural abscesses could be located and their decompression monitored. MR imaging is recommended as the initial screening procedure in spinal infection; in those few patients with nondiagnostic MR images, myelography with high-resolution CT should be the supplementary study. If surgery is planned, intraoperative spinal US should be used.
Abscess↗
Improved MR imaging of the brain by using compensating gradients to suppress motion-induced artifacts.
Sixty patients were examined with and without extra gradient pulses, which compensate for motion-induced phase errors, in order to determine the effect those gradients had in suppressing the motion artifacts frequently present in the brainstem, temporal lobes, and basal ganglionic regions on routine T2-weighted brain MR imaging. Two comparative studies were performed: (1) in 50 patients the motion-artifact suppression technique (MAST) was compared with a single-echo MR examination, and (2) in 10 patients the MAST technique was compared with the second echo of a symmetric dual-echo sequence. In the first study 39 patients were examined at 1.5 T and 11 patients were examined at 0.5 T with the same pulse sequences. We found that MAST resulted in a significant improvement of image quality in 24 of 39 patients on the high-field-strength system and in two of 11 patients on the mid-field-strength system. In the second study, we found that in four of the 10 patients, MAST resulted in a suppression of artifacts greater than that achieved by even-echo rephasing alone. With MAST, artifacts were eliminated that not only obscured normal structures but that could have left doubt about the presence of a true signal abnormality. There was, however, marked suppression of the CSF flow-void phenomenon and increased signal from flowing blood, particularly in the cortical veins and dural sinuses. Because of this, the use of additional pulse sequences in which these motion-compensating gradients were not used was necessary under certain clinical circumstances. We conclude that, with these motion-compensating gradients, artifacts are reduced or eliminated, and a marked improvement in image quality can be obtained without the need for cardiac gating.
Adolescent↗
CT, MR, and pathology in HIV encephalitis and meningitis.
The value and limitations of CT and MR in human immunodeficiency virus (HIV) infection of the brain was determined by a retrospective analysis of the CT scans (22) and MR images (7) in 22 patients with pathologically proved HIV encephalitis (21) or meningitis (1). Our clinical-radiologic-pathologic correlation suggested that, especially in the early stages of the disease, CT and MR were relatively insensitive in detecting the primary changes of HIV encephalitis. The multiple bilateral diffuse microscopic glial nodules with multinucleated giant cells of HIV found at autopsy in both gray and white matter were usually not directly visualized by either CT or MR. Secondary, nonspecific changes, however, were seen. These included cortical atrophy, found in virtually all patients with HIV encephalitis, and HIV-induced foci of demyelination found in the minority of cases. On CT the latter were seen in the white matter as nonenhancing, nonmass-producing areas of low density; on MR they were seen as frequently progressive high-intensity signal abnormalities on T2-weighted images, usually in the periventricular white matter and centrum semiovale. MR was more sensitive in detecting these demyelinative lesions than was CT. The clinical diagnosis of HIV encephalitis usually antedated the radiographic diagnosis. In HIV meningitis, contrast CT was more definitive than MR, showing striking enhancement of the subarachnoid spaces, although MR was more sensitive in detecting the secondary parenchymal changes.
Acquired Immunodeficiency Syndrome↗
Progressive cytomegalovirus encephalopathy following congenital infection in an infant with acquired immunodeficiency syndrome.
Congenital central nervous system infection with cytomegalovirus (CMV) usually results in a nonprogressive encephalopathy. Ninety percent of patients with clinically apparent infections at birth have a permanent neurological disability. It has been suggested that some infants may have persistent infection manifested by progressive encephalopathy during infancy. In the present case, clinical and pathological findings suggest the reactivation of a prior intrauterine CMV infection in a child with human T-lymphotrophic virus type III (HTLV-III) infection. The presence of HTLV-III may have reduced the immune surveillance of this infant, allowing the CMV to reactivate.
Acquired Immunodeficiency Syndrome↗
Intraoperative sonography in spinal dysraphism and syringohydromyelia.
The use of intraoperative sonography was analyzed in 24 patients with spinal dysraphism and syringohydromyelia in order to determine the role of real-time sonography in the surgical management of these patients. Specific diagnoses included tethered cord (nine), syringohydromyelia (seven), congenital tumor unassociated with a tethered cord (four), diastematomyelia (three), and occult sacral meningocele (one). Intraoperative sonography determined the exact relationship of congenital tumors to the cord before opening the dura, which allowed a more precise approach to the mass. Intraoperative sonography identified the lower end of the syrinx cavities, which allowed optimal catheter placement. Fibroglial scar tissue, which may compartmentalize these syrinx cavities, was clearly shown, and the efficacy of shunt catheter placement was immediately determined. In diastematomyelia, intraoperative sonography identified the relationship of the hemicords to bony, cartilaginous, and/or fibrous septa and demonstrated the effect on the tethered hemicords of removing these septa and constructing a single dural sac from the two dural sacs that had enclosed the hemicords. Since significant surgical decisions are based on these sonographic observations, the authors urge widespread use of intraoperative sonography in patients with spinal dysraphism and syringohydromyelia.
Humans↗
Intramedullary spinal cord metastases, mainly of nonneurogenic origin.
The clinical data and imaging studies of 12 patients with intramedullary metastases were reviewed retrospectively to see if these lesions had a typical radiographic appearance and to determine the sensitivity of the various radiologic examinations. The lesions were identified antemortem by either myelography, CT, MR, and/or intraoperative spinal sonography (IOSS). Final diagnosis was based on biopsy material from either the spinal cord lesion, another metastatic site, and/or the primary tumor. Ten patients had primary tumors located outside the central nervous system, while only two patients had primary brain tumors. Metrizamide myelography and CT demonstrated a definite intramedullary mass in nine of 11 patients. In five patients the mass was relatively small, well-defined, single, and resembled a primary spinal cord neoplasm. In the other four patients, longer and sometimes several segments of the cord were involved. These appeared irregular and nodular and were often associated with intradural lesions at separate sites. MR detected not only enlargement and abnormal signal in the cord but also clinically unsuspected brain lesions. IOSS localized lesions for biopsy and monitored tumor resection. These various imaging procedures showed that cord metastases were often more extensive than anticipated clinically. Spread of tumor into the spinal and intracranial subarachnoid space was common. Imaging of the entire spinal canal and brain, preferably with MR, is therefore recommended to aid in diagnosis, prognosis, and treatment.
Adult↗
Progressive multifocal leukoencephalopathy associated with human immunodeficiency virus infection. A review of the literature with a report of sixteen cases.
Progressive multifocal leukoencephalopathy, a common complication of infections with human immunodeficiency virus (HIV), occurs in as many as 3.8% of patients with the acquired immunodeficiency syndrome (AIDS). We report 16 cases and review 12 previously reported cases of progressive multifocal leukoencephalopathy associated with HIV infection. This illness was the presenting manifestation of HIV infection in 8 cases. Limb weakness, gait abnormalities, visual loss, aand altered mental status were the commonest initial complaints. Computed tomography of the brain frequently showed hypodense, nonenhancing white matter lesions. Magnetic resonance imaging was more sensitive than computed tomography in detecting lesions. Cerebrospinal fluid analysis and electroencephalography were nondiagnostic. Impaired cell-mediated immunity was typically noted, even in the absence of other immunodeficiency-associated illnesses. Death occurred within 10 days to 18 months of the onset of symptoms in 22 patients. However, 4 patients remain alive at 3 to 23 months; of these 4, 2 have had significant improvement without treatment. Various therapies were unsuccessful.
Acquired Immunodeficiency Syndrome↗
Involvement of cavernous sinus region by malignant neoplasms: report of 5 cases.
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Adult↗
Central nervous system disease in acquired immunodeficiency syndrome: prospective correlation using CT, MR imaging, and pathologic studies.
A prospective study compared the abilities of high-resolution computed tomography (HRCT) and magnetic resonance (MR) imaging in detection and evaluation of central nervous system disease in neurologically symptomatic patients with acquired immunodeficiency syndrome (AIDS). Eighteen CT scans and 19 MR images in 14 patients were compared. HRCT images with contrast material enhancement were superior to unenhanced 0.35-T MR images for differentiating a lesion from surrounding edema, discriminating between lesions in close proximity, locating lesions for biopsy, judging lesion activity, detecting small cortical lesions with minimal edema, and spatial resolution. MR imaging was superior to CT scanning in evaluation of white-matter lesions and detection of small lesions surrounded by edema. MR imaging exhibited higher contrast resolution and greater sensitivity. Complementary uses of MR and CT imaging are suggested.
Acquired Immunodeficiency Syndrome↗