Biomedical subjects
Publications and source records attributed to G Birbamer.
In 1999, a Task Force on Mild Traumatic Brain Injury (MTBI) was set up under the auspices of the European Federation of Neurological Societies. Its aim was to propose an acceptable uniform nomenclature for MTBI and definition of MTBI, and to develop a set of rules to guide initial management with respect to ancillary investigations, hospital admission, observation and follow-up.
Preparation of thin serial sections for comparative macromorphologic investigations has always represented a grave technical problem, especially in the case of regions in which bone as well as soft tissue are to be documented within their natural relations to each other in any desired sectional plane. Non-decalcified specimens up to the size of a whole cadaver are embedded in physiologic medium, precisely positioned, and deep-frozen to a specimen-ice block. A newly developed device, working on the basis of blades rotating at high speed, allows quick, successive removal of sections from the surface of the specimen block, with a thickness of each section infinitely variable between 0.1 and 5 mm. Following each cut, the new surface of the block can be documented photographically or on videotape for macromorphologic evaluation. So far more than 1,000 human, animal, and botanical specimens have been sectioned and evaluated with this method. In none of the cases were specimens damaged. Furthermore, any desired sectional plane could be adjusted: consequently a definite correlation between these sections and previous sonography, magnetic resonance (MR), or computed tomography (CT) images could be established. As serial cryosectioning becomes available to a far wider circle of medical and natural scientists, high-quality results should be obtained at lower costs.
The aim of this study was to evaluate the relationship between phenytoin medication and cerebellar atrophy in patients who had experienced clinical intoxication. Five females and 6 males, 21-59 years of age, were examined with a 1.5-T whole-body system using a circular polarized head coil. Conventional spin echo images were acquired in the sagittal and transverse orientation. In addition, we performed a high-resolution 3D gradient echo, T1-weighted sequences at a 1-mm slice thickness. The images were subsequently processed to obtain volumetric data for the cerebellum. Cerebellar volume for the patient group ranged between 67.66 and 131.08 ml (mean 108.9 ml). In addition 3D gradient echo data sets from 10 healthy male and 10 healthy female age-matched volunteers were used to compare cerebellar volumes. Using linear regression we found that no correlation exists between seizure duration, elevation of phenytoin serum levels and cerebellar volume. However, multiple regression for the daily dosage, duration of phenytoin treatment and cerebellar volume revealed a correlation of these parameters. We conclude that phenytoin overdosage does not necessarily result in cerebellar atrophy and it is unlikely that phenytoin medication was the only cause of cerebellar atrophy in the remaining patients. Quantitative morphometric studies of the cerebellum provide valuable insights into the pathogenesis of cerebellar disorders.
PURPOSE: To assess the value of MR imaging in the acute and chronic stages of spinal trauma. METHODS: 126 MR examinations of 120 patients were evaluated retrospectively. In 15 cases of acute spinal cord injury, correlation of MR findings with the degree of neurological deficit and eventual recovery was undertaken. RESULTS: Cord anomalies in the acute stage were seen in 16 patients. Intramedullary haemorrhage (n = 6) and cord transection (n = 2) were associated with complete injuries and poor prognosis, whereas patients with cord oedema (n = 7) had incomplete injuries and recovered significant neurological function. In the chronic stage, MR findings included persistent cord compression in 8 patients, syringomyelia or post-traumatic cyst in 12, myelomalacia in 6, cord atrophy in 9, and cord transection in 7 patients. CONCLUSION: In acute spinal trauma, MR proved useful in assessing spinal cord compression and instability. In addition, direct visualisation and characterisation of post-traumatic changes within the spinal cord may offer new possibilities in establishing the prognosis for neurological recovery. In the later stages, potentially remediable causes of persistent or progressive symptoms, such as chronic spinal cord compression or syringomyelia can be distinguished from other sequelae of spinal trauma, such as myelomalacia, cord transection or atrophy.
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Mild overdosage of phenytoin produces reversible cerebellar symptoms (nystagmus, double vision, dysarthria and ataxia). Several case reports suggest that relatively mild and relatively short intoxication can lead to cerebellar degeneration. We observed 11 patients who had episodes of abnormally increased serum levels, most of which developed clinical signs of cerebellar dysfunction. All of these patients were examined with a 1.5-tesla whole-body system (Magnetom, Siemens). Five patients had normal cerebellar structures, although 3 of them had a history of clinical intoxication and all had at least one episode of increased serum level of diphenylhydantoin. The remaining 5 had moderate to severe cerebellar atrophy. Two of them never experienced signs of clinical intoxication. There was no correlation between degree of atrophy and severity of clinical symptoms and elevation of serum DPH levels. There was no correlation between cerebellar atrophy, duration of epilepsy and frequency of seizures.
Epidural and subdural spinal hematomas were previously diagnosed by myelography and computed tomography (CT). Recent reports indicate that noninvasive detection is possible with magnetic resonance imaging. We report on nine patients who were investigated by magnetic resonance imaging (MRI) prior to surgery for epidural and subdural spinal hematoma. The MR examinations were performed on 1.5-T and 1-T units. We used surface coils and employed T1-, PD- and T2-weighted spin echo sequences and a T2*-weighted gradient echo sequence. CT was available in four patients and myelography in two patients. Surgical correlation was available in all patients. The hematomas were located in the cervical spine (n = 2), thoracic spine (n = 6) and lumbar spine (n = 2). They were epidural in five patients and subdural in four. Blinded reading correctly identified all five epidural hematomas and three of the subdural hematomas; one subdural hematoma was misjudged as epidural. Peracute hematomas (< 24 h) in three patients appeared isointense or slightly hyperintense on T1-weighted images and had mixed signal intensity on T2- and T2*-weighted images. Acute hematomas (1-3 days) in four patients were also isointense on T1-weighted images but were more hypointense on T2- and T2*-weighted images. Chronic hematomas in two patients (7 days and 14 days) were hyperintense on all sequences. Differentiation between epi- and subdural hematomas required transverse T2*-weighted gradient echo sequences. Our results underline that MRI at 1 and 1.5 T is capable of identifying epidural and subdural spinal hematoma in the acute and peracute stage.(ABSTRACT TRUNCATED AT 250 WORDS)
The concept of "Inner cerebral trauma" (ICT) has been preliminary defined as a characteristic topographic pattern of deep brain lesions produced by physical forces occurring within the cranial cavity in closed head injury of the acceleration/deceleration type. The lesions, based on neuropathological examinations, are characteristically localized in the "centro-axial" regions of the brain. The extent of ICT is often underestimated by CT. Due to assess the value of MR imaging, 83 patients with ICT were examined on a 1.5 T unit in different stages after trauma. The pattern of lesions, as shown with MR imaging, correlated well with neuropathological studies, suggesting a multifocal pathogenesis of severe traumatic brain injury.
A 35-year-old man presented with the clinical picture of spontaneous subarachnoid hemorrhage. Four weeks after the first symptoms he noticed blurred vision, and ophthalmological examination detected bitemporal hemianopia. At this time cerebral computed tomography and magnetic resonance imaging showed enlargement of the optic chiasm, and visual evoked potentials revealed delayed latencies. In the cerebrospinal fluid cells and protein content were elevated, and angiotensin-converting enzyme was detectable. Under steroid treatment the patient recovered completely and computed tomography, magnetic resonance imaging, visual evoked potentials, and cerebrospinal fluid findings became normal. Although a great variety of neurological symptoms may occur in neurosarcoidosis, to our knowledge spontaneous subarachnoid hemorrhage as the presenting feature has never been reported before.
Two patients are described, in whom MRI detected unilateral signal abnormalities in the region of the inferior olivary nuclei, suggesting an early stage of olivary hypertrophy. MRI was performed 4 and 7 weeks respectively after traumatic brain-stem injury. Palatal myoclonus was concomitantly observed in one patient, while the other showed no evidence of segmental myoclonus at the time of examination. The authors conclude that MRI is highly sensitive in the detection of olivary hypertrophy and of traumatic lesions of the dentato-rubro-olivary pathway.
Today, patients with alveolar rhabdomyosarcoma have a favorable prognosis with a survival rate of more than 80%, due to modern radiotherapy. However, those patients with secondary meningeal involvement are still afflicted with a mortality rate of 90% unless a different therapeutic approach is taken. We report a case of a young adult with invasion of the tumor into the anterior cranial fossa. MRI aided in the assessment of the intracranial tumor spread and allowed for a direct visualization of the meningeal membranes. The signal characteristics of the tumor and the adjacent tissue in unenhanced and postcontrast MRI is discussed. MRI was clearly superior to CT and indicative for the choice of treatment.
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120 wrists of 105 patients with carpal tunnel syndrome were studied preoperatively by high-resolution sonography. Follow-up examinations after carpal tunnel release were performed in 72 wrists. In addition, 40 wrists were examined preoperatively, and 20 wrists were examined postoperatively by MR imaging. Based on quantitative analysis of the cross-sectional area and shape of the median nerve and of the palmar bowing of the flexor retinaculum, sonography established the diagnosis in 95% of cases. MR was superior in the evaluation of mild degrees of median nerve compression, and in the detection of possible causes of the carpal tunnel syndrome, such as synovitis of the flexor tendon sheaths or ganglionic cysts. In postoperative follow-up, sonographic demonstration of a normally flattened median nerve was an excellent indicator of the successful carpal tunnel release. In 10 patients with persistent or recurrent symptoms after carpal tunnel release, the underlying pathology could be exactly demonstrated by MR.
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A man with known pulmonary sarcoidosis presented with paraplegia and a rod-shaped increase in T2 signal intensity in his cervical and upper thoracic spine. Initial treatment efforts using oral doses of 40 mg of methyl-prednisolone were futile, but intravenous bolus therapy (500 mg of methyl-prednisolone daily for 1 week) led to long-lasting improvement of his neurological status and to normalization of MRI findings.
We present clinical and magnetic resonance (MR) findings in three patients with segmental myoclonia occurring 11-18 months after severe brainstem injury. Palatal myoclonus and vertical ocular myorhythmia were present in all three patients and synchronous involuntary movements of the upper extremities ("wing beating") in two patients. MR-imaging showed multiple post-traumatic lesions within the dentato-rubro-olivary pathway ("myoclonic triangle"), associated with bilateral enlargement and increased signal intensity of the inferior olives. The signal abnormality was more prominent on proton density weighted images than on T2-weighted images, suggesting underlying pathological changes different from typical gliosis.
The case of a 30-year-old man with posttraumatic syringomyelia involving the cervical and upper thoracic spine is reported. The patient was followed clinically and with magnetic resonance (MR) imaging over a 3-year period. Spontaneous complete remission of the syrinx-related symptoms correlated with a partial collapse of the syrinx, as proved by serial MR imaging.