Experimental syringomyelia: late ultrastructural changes of spinal cord tissue and magnetic resonance imaging evaluation

Seroprevalence for CMV varies from 70% in the general population to more than 90% in HIV infected patients. Immunodepression whatever its origin, either post therapeutic as in transplant recipients, or induced by HIV, leads to the reactivation of this virus, present in a latent form in the host. In CMV-seronegative patients, the main prevention is based on donor matching before a graft (graft of seronegative donor) and on the use of seronegative blood products or deleukocyted blood. Since the availability of efficient strategies of prophylaxis (before infection) or of early treatment (pre-emptive therapy), CMV disease is now infrequent in most transplantation centers. A real prophylaxis with ganciclovir is usually selected in high risk patients (lung, bone marrow transplants in case of a CMV seropositive recipient or seronegative but with a seropositive donor). It has replaced in most centers aciclovir that has only a modest efficacy. A pre-emptive therapy by ganciclovir is proposed in case of lower risk of CMV disease (kidney, liver or heart transplants) or if the local virology laboratory provides sensitive virological markers to detect the first signs of CMV reactivation. Besides viremia or pp65 antigenemia, currently used to initiate a pre-emptive therapy, the standardisation of other virological markers such as leukocytic or plasmatic PCR is in progress. The prophylaxis of CMV disease in less developed for HIV infected patients. Immunosuppression, continuously progressing in absence of antiretroviral agents, requires a continuous prophylaxis for months or years, treatment that is difficult to propose at the present time considering the modest activity of oral ganciclovir, the only oral agent available. Future progresses in this field will be obtained when a sensitive and reproductible CMV marker will allow to identify the patients at highest risk of CMV disease, and with new anti-CMV agents having a good oral bioavailability.     

Evolving magnetic resonance spinal cord trauma in child: from hemorrhage to intradural arachnoid cyst

Acquired arachnoid cysts of the spinal cord are uncommon causes of spinal cord compression in the pediatric group. Meningitis, trauma and hemorrhage are considered to be causative or contributing factors. Interestingly, no spinal arachnoid cysts have been reported in patients after subarachnoid hemorrhage or meningitis, conditions expected to cause arachnoid scarring. We describe a child of 1 year and 10 months with thoracic spine trauma with crural paraplegia and anesthesia at level T5 submitted to serial magnetic resonance imagery at 5 days and 18 months, after trauma showing evolution from subarachnoid hemorrhage and adhesions of the arachnoid space to a posterior hypertensive thoracic intradural arachnoid cyst.     

Injuries of the cervical spine and spinal cord in patients with ankylosing spondylitis--diagnosis using magnetic resonance imaging

Magnetic resonance (MR) imaging results in 8 from 14 ankylosing spondylitis patients treated of traumatic cervical spine and spinal cord injuries are presented. Focal changes within spinal cord were most common among complications (62%), epidural hematoma was found in 50% of cases. Neurological status has worsened in patients with post-traumatic spinal cord pathology.     

Magnetic resonance imaging in cervical spinal cord compression

In patients with cervical spondylotic myelopathy MRI sometimes shows increased signal intensity zones on the T2-weighted images. It has been suggested that these findings carry prognostic significance. We studied 56 subjects with cervical spinal cord compression. Twelve patients showed an increased signal intensity (21.4%) and a prevalence of narrowing of the AP-diameter (62% vs 24%). Furthermore, in this group, there was evidence of a longer mean duration of the symptoms and, in most of the patients, of more serious clinical conditions. The importance of these predisposing factors remains, however, to be clarified since they are also present in some patients without the increased signal intensity.     

Magnetic resonance imaging of experimental subacute spinal cord compression

STUDY DESIGN: Subacute compression of the spinal cord was applied to rats. The animals were chronologically observed using magnetic resonance imaging for more than 8 weeks after surgery and were killed for histopathologic examination. OBJECTIVES: To investigate the correlation of changes in signal intensity on magnetic resonance images with those observed in histopathologic study and with the degree of spinal cord compression and paralysis. SUMMARY OF BACKGROUND DATA: No consensus has been reached concerning the correlation of magnetic resonance images to clinical symptoms of compressive myelopathy. Few reports are available in which magnetic resonance imaging findings are compared with histopathologic features in chronic or subacute experiments. METHODS: In rats under general anesthesia, the T11 lamina was thinned and a slow increase in volume was applied. Hind limb paralysis appeared 1 week after the procedure and spontaneously subsided thereafter. The degree of spinal compression and signal intensity was observed chronologically using magnetic resonance imaging. The signal intensity on the final MR images was rated on a four-point scale and compared with histopathologic findings. RESULTS: As spinal compression increased, the incidence of high signal intensity on long spin-echo images became higher. Low signal intensities on short spin-echo images were visible in animals in which compression and paralysis were the most severe. In these animals, cavitation and a dilated central canal were visible. High signal intensities on long spin-echo images reflected various pathologic changes. CONCLUSIONS: Changes in signal intensity on MR images are visible after the induction of myelopathy by high-pressure compression. These signal intensities may be useful in predicting the outcome of compressive myelopathy.     

Incidence and risk factors in the appearance of heterotopic ossification in spinal cord injury

Heterotopic ossification (HO) is a frequent complication in patients with a spinal cord injury (SCI), although the aetiology is unknown. A study was undertaken of 654 SCI patients with traumatic aetiology, admitted for the first time to the Hospital Nacional de Paraplejicos, Toledo, during 1988 and 1989. Of the total number of patients, 85 (13%) were diagnosed HO and 569 without HO. The diagnosis was mainly achieved by x-ray studies and clinical signs. From the 569 patients with traumatic aetiology without HO, 44 were selected at random, as were 44 of the 85 patients with HO. The mean time lapse between the occurrence of the accident and admission for patients with HO was 40.79 days (typical deviation (TD) = 45.2), and for patients without HO was 32.84 (TD = 38) days, resulting in a value of F = 0.796 through analysis of variance, which is not a statistically significant variation between the 2 groups. In both groups we have taken account of the following variables: age at time of lesion, lesion level, type of lesion (complete or incomplete), spasticity, urinary tract complications, deep vein thrombosis, important associated injuries occurring at the moment of lesion, time elapsed before admission and the existence of pressure sores. In those SCI patients with HO the number of ossifications and their localisations were also verified. By use of the chi square test (X2) over all 9 variables which were studied, we found that 3 variables (complete spinal lesion, presence of pressure sores and spasticity) were significantly related to HO formation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transverse myelitis. Comparison with spinal cord presentations of multiple sclerosis

This study reports results 1 year after treatment for 77 obese women who had been treated for 48 weeks by diet combined with supervised (a) aerobic exercise, (b) strength training, (c) aerobic plus strength training combined, or (d) no exercise. Mean (+/- SD) end-of-treatment weight losses for the 4 conditions ranged from 13.5 +/- 9.1 kg to 17.3 +/- 10.3 kg, but there were no statistically significant differences among groups. Participants in all 4 conditions regained approximately 35% to 55% of their weight loss in the year after treatment; again, there were no significant differences among groups. Participants, however, who reported exercising regularly in the 4 months preceding the follow-up assessment regained significantly less weight than did nonexercisers.     

The role of magnetic resonance imaging studies in multiple sclerosis

Multiple sclerosis (MS) is a common cause of disability in young adults. Establishing a definitive diagnosis of the disease is often difficult, and there is much uncertainty concerning prognosis once the diagnosis is made. Magnetic resonance imaging (MRI) studies have proved to be a useful diagnostic test in the initial evaluation and monitoring of patients with MS. They also provide a means for quantitative assessment of disease activity and progression during clinical trials of MS therapies. Improvements in MRI technology show promise in providing more accurate measurements of disease extent. The new technique of magnetic resonance spectroscopy can be used to monitor the specific pathophysiology of evolving MS plaques in vivo and may provide insights that lead to a better understanding of the pathogenesis of MS.     

Determinants of image appearance in contrast-enhanced magnetic resonance angiography. A review

The use of contrast agents in magnetic resonance (MR) studies of vascular pathology has permitted the exploration of regions that were heretofore poorly evaluated with conventional magnetic resonance angiography (MRA). An important feature of contrast-enhanced MRA (CE-MRA) is the very short acquisition times that are possible. The determination of the parameters to be used in a CE-MRA study rests on an understanding of the dynamics of the passage of the injected contrast agent and the response of the magnetization to the parameters of the MR imaging sequence. An overview of this interaction is presented.     

Quantitative cerebral magnetic resonance imaging during ACTH treatment of multiple sclerosis

Serial MR scans were performed with the 2DFT imaging method and the filtered backprojection imaging method on 12 patients with multiple sclerosis in acute phase, 4 in a relapsing/remitting form, and 8 in a progressive form, before, during and after ACTH treatment. Both T1 and T2mono relaxation times, obtained by fitting transverse magnetization decay curves with a monoexponential function within the apparently normal white matter and the areas of increased signal, were measured. With the backprojection method it was possible to fit the transverse magnetization decay curve with a biexponential function and obtain T2long and T2short relaxation times. The T2mono and T1 relaxation times of the apparently normal white matter were significantly different from those obtained for volunteers, but no significant differences were found before, during, or after treatment. The transverse magnetization decay curves of the areas of increased signal were better fitted by a biexponential function. No significant changes in these relaxation times were observed after ACTH treatment. These results argue against an anti-oedematous action of ACTH and may suggest that it has an immunosuppressant effect.     

The contrast enhancement of brain and spinal cord tumors using Gd-DTPA in magnetic resonance tomography with an extra-low magnetic-field intensity

The contrasting agent Gd-DTPA (Magnevist, Schering AG, Germany) was tested when used in magnetic resonance tomography using extra-low (0.04 T) magnetic field intensity in 68 patients with various brain and spine tumors. The agent was injected intravenously in a dose of 0.1 mmol/kg. No complications were found. The tests showed its high efficiency in the diagnosis of brain neoplasms (particularly in malignant intracerebral disorders, meningiomas and neurinomas). Benign astrocytomas induced no noticeable signal intensification on post-contrasting T1-weighed tomograms. In all cases of spinal tumors, the application of Gd-DTPA could specify the extent of tumor invasions, the presence of cysts and identify accessory tumor nodes in one case.     

Multiple sclerosis: basic immunology

A 24-year-old male presented with a 4 year history of a crusted erythematous papular eruption of the scalp and external auditory meati and a 12 month history of painful perianal ulceration. A diagnosis of Langerhans cell histiocytosis was made and confirmed by skin histology. Extensive investigation revealed no systemic involvement. Rapid improvement occurred after intravenous 2-chlorodeoxyadenosine but relapse of perianal lesions occurred within 5 months. Local radiotherapy to the perianal region resulted in a complete remission sustained over 12 months.     

Serial neuropsychological assessment and magnetic resonance imaging analysis in multiple sclerosis

OBJECTIVE: To assess the correlation between cognitive dysfunction and disease burden in multiple sclerosis (MS) during a 1-year period. DESIGN: The Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis was performed at entrance and 1 year. Patients underwent at least 20 proton density (range, 20-24) and T2-weighted axial magnetic resonance imaging (MRI) brain scans except for stable patients who were scanned monthly. Magnetic resonance imaging was evaluated using computer-automated, 3-dimensional volumetric analysis. SETTING: A research clinic of a university hospital. PATIENTS: Forty-four patients with MS of the following disease categories: relapsing-remitting (14), relapsing-remitting progressive (12), chronic progressive (13), and stable (5). MAIN OUTCOME MEASURES: The relationships between scores on the Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis and 2 MRI measures (total lesion volume and brain to intracranial cavity volume ratio) were assessed using linear regression. These MRI measures were also compared with cognitive status at 1 year using analysis of variance. RESULTS: Overall, there was no decline in mean cognitive test performance during 1 year. Significant correlations were found between baseline neuropsychological test scores of nonverbal memory, information-processing speed, and attention and both MRI measures. Patients with chronic progressive MS demonstrated the strongest correlations. At 1 year, change in information-processing speed and attention correlated with change in total lesion volume. The mean increase in total lesion volume was 5.7 mL for 4 patients whose cognitive status worsened compared with 0.4 mL for 19 patients who improved and 0.5 mL for 21 patients who remained stable. CONCLUSIONS: During a 1-year period mean cognitive performance did not worsen. Automated volumetric MRI measures of total lesion volume and brain to intracranial cavity volume ratio correlated with neuropsychological performance, especially in patients with chronic progressive MS. Worsening MRI lesion burden correlated with cognitive decline.