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Biomedical subjects

G Schroth

Publications and source records attributed to G Schroth.

At least 163 records · Page 9Linked to original sources

Influence of magnetic resonance imaging on somatosensory and brain-stem auditory evoked potentials in man.

There is still a need to prove that even static magnetic fields up to 1.5 T used in magnetic resonance imaging (MRI) are biologically safe and harmless for humans. Recordings of median and ulnar nerves and brain-stem auditory evoked potentials in 20 patients were completed prior to and after MRI investigation of the central nervous system. Neither the somatosensory nor the auditory evoked potentials exhibited any significant change of latencies, interpeak latencies or amplitudes. Since these electrophysiological parameters are highly dependent on the quality of nerve conduction and integrity of information processing in various nuclei, it may be assumed that MRI causes no lasting changes in either respect.

Adult↗

MR imaging in tumors of the pineal region.

Ten patients with tumors of the pineal region underwent CT and MRI investigations. There were 3 germinomas, 3 teratomas and 1 of each of the following: pineocytoma, PNET, ependymoma and meningioma. Not only were tumor size and growth compared to CT, but an attempt was made to obtain knowledge of the histology of the tumor by special T2 calculations. The investigations did not lead to an improvement in type specific diagnosis.

Brain Neoplasms↗

Reversible brain shrinkage in abstinent alcoholics, measured by MRI.

Magnetic resonance imaging of the intracranial CSF volume was compared before and after 5 weeks of confirmed abstinence in 9 alcohol-dependent patients. All patients showed a highly significant reduction in CSF volume in accordance with reexpansion of the brain after alcohol abstinence. T2 values for white matter, estimated by linear regression from 16 echoes of a CPGM sequence, however, showed no significant increase such as occurs in rehydration. This indicates, that alcohol-induced reversible brain atrophy cannot be attributed to fluctuation of free water in the brain only.

Adult↗

[Syringomyelia: correlation of magnetic resonance tomographic and clinical findings before and after surgery].

A comparison between clinical and MRI findings in 20 patients with syringomyelia produced the following results: 1. The position and extent of the syrinx do not correspond with the clinical findings. 2. Successfully operated syringomyelia cavities collapse in their sagittal diameters. The resulting oval shape of the syrinx can be used to evaluate shunt insufficiency. 3. In almost half of the patients, the diameter of the spinal cord is within the 95th percentile of normal controls and would therefore not have been diagnosed by myelography. 4. Anomalies of the cranio-cervical junction were present in only one-third of the patients. This finding does not support the hypothesis that syringomyelia is caused by hydrodynamic factors only.

Adult↗

Advantage of magnetic resonance imaging in the diagnosis of cerebral infections.

18 patients with cerebral infections were investigated with a 1.5 Tesla-Magnetom. The results are compared to CT-findings obtained at the same time. In the majority of cases (n = 11) MR is superior to CT because it allows earlier detection of the disease, a more exact definition of the spread and a more detailed representation of complex inflammatory processes. MRI should rank first among all examination methods, especially in the determination of herpes simplex-encephalitis as it allows earlier detection and treatment of this disease.

Adult↗

Contribution of MRI in the diagnosis of haemangioblastomas.

Magnetic resonance imaging (MRI) patterns of 11 haemangioblastomas examined with a 1.5-T scanner are described. MRI was as effective as contrast-enhanced CT in the detection of vascular tumour components, but was less sensitive than angiography. MRI was superior to CT in delineating the exact extent of the lesions, for example contact with the arachnoid surface. Even if a cystic tumour component is absent, MRI can provide helpful criteria for differential diagnosis; in particular, T2 values allow differentiation from meningiomas. In three patients additionally administered gadolinium (Gd) diethylenetriaminepenta-acetic acid (DTPA) the angiomatous parts of the tumour showed a remarkable decrease in T1 value, but the time dependence of the enhancement was not the same as that seen in dynamic CT.

Adolescent↗

Paraneoplastic cerebellar degeneration associated with Hodgkin's disease.

A case of paraneoplastic cerebellar degeneration (PCD) associated with Hodgkin's disease is presented. The features that make this case particularly interesting are the simultaneous occurrence of PCD with a relapse of Hodgkin's disease, which has been present for 17 years, and the arrested progression of cerebellar dysfunction after a subacute onset. Cerebellar atrophy was revealed by computed tomography and magnetic resonance imaging. In contrast to two previously reported cases, anti-Purkinje-cell antibodies were not detected.

Adult↗

[MR tomographic demonstration of liquor pulsation].

With ECG-gated FLASH-sequences motion of cerebrospinal fluid (CSF) is demonstrated in axial slices of the zervikal vertebral column. The course of the movement is dissolved by signal enhancement of flowing structures in magnitude images and by velocity-dependent phases. It is shown with both methods, that the oscillation of the CSF within the cardiac cycle is superimposed by a directed movement, with is cranial directed in the lateral cervical subarachnoidal spaces and caudal in the ventral subarachnoidal spaces.

Cerebrospinal Fluid↗

Magnetic resonance imaging of the brain of children with multiple sclerosis.

The results of magnetic resonance imaging (MRI) of the brains of three children with multiple sclerosis were compared with the results of computer tomography (CT). MRI made it possible to detect a particular configuration of white-matter hyperintensities with sharply angled patches and a multifocal pattern, even during remission. Thus the site and extent of cerebral plaques could be demonstrated more clearly and more exactly than with CT. At present MRI seems to be the most reliable method for confirming suspected cases of multiple sclerosis in childhood.

Brain↗

Early diagnosis of herpes simplex encephalitis by MRI.

The mortality rate of herpes simplex encephalitis (HSE) may be reduced by antiviral therapy, but early administration of the drug and therefore early diagnosis are essential. In our experience with four cases, MRI is the most sensitive noninvasive test in early diagnosis of HSE due to its high sensitivity to inflammatory increased brain water content, and it is superior to CT in localizing the pathognomonic lesions of the limbic system.

Child↗

Magnetic resonance imaging of spinal meningiomas and neurinomas. Improvement of imaging by paramagnetic contrast enhancement.

The detection and delineation of spinal tumors by magnetic resonance imaging (MRI) after intravenous administration of gadolinium (Gd)-diethylenetriaminepenta-acetic acid (DTPA) is demonstrated in eight cases of neurinoma or meningioma. The advantages of Gd-DTPA-enhanced MRI over other MRI techniques used in more than 100 cases of spinal cord diseases are described.

Adult↗

[Nuclear magnetic resonance tomography: a new imaging diagnostic procedure of the petrous bone and cerebellopontile angle].

Nuclear magnetic resonance imaging (NMRI) is a new technique enabling three dimensional scanning of the petrous bone without ionizing radiation. Contrary to computer tomography NMRI enables visualization of the structures of the inner ear and the cerebello-pontine angle without masking by overprojecting bony structures. The resolution of inflammatory processes and tumors is excellent. NMRI is inferior to CT in demonstrating bony destruction, and is therefore not so effective in the evaluation of glomus tumours. The use of surface coils in combination with a special gradient-zoom-technique allows high resolution imaging. This and Gadolinium-DTPA for enhancement opens new perspectives in the diagnosis of small acoustic neuromas.

Cerebellar Neoplasms↗

Superior sagittal sinus thrombosis: neuroradiological evaluation and clinical findings.

The spectrum of clinical signs in cases of superior sagittal sinus thrombosis includes not only focal neurological deficits, seizures and mental disturbances, but also symptoms which may lead to a diagnosis of pseudotumour cerebri (PTC). In 14 cases of angiographically (or autopsy) proven thrombosis of the superior sagittal or both lateral sinuses, the "empty triangle" sign on contrast CT examination was the most reliable sign, suggesting the diagnosis in 70%. Indirect CT signs (venous infarcts) were observed in all 8 patients with focal neurological signs, but appeared rather delayed in 3 cases. In contrast, patients with "benign" intracranial hypertension or PTC (6 cases) had normal unenhanced scans (4 cases) or showed slight diffuse brain oedema (2 cases). Magnetic resonance imaging was performed in 4 patients with findings suggestive of intravascular coagulation; however, due to the complexity of flow phenomena, further studies employing this new imaging technique will first have to be performed. Thus, angiography remains the best diagnostic tool and should not be delayed if there is a clinical suspicion of thrombosis.

Adolescent↗

The value of paraxial slices in MR-imaging of spinal cord disease.

Paraxial slices in MRI of the spinal cord reveal information about anatomical structures and pathological processes not available from orthogonal plane images or other diagnostic methods. They also yield a profit in diminishing the artifacts that occur from heart movement and respiration when triggering is not employed.

Adult↗

Magnetic resonance imaging (MRI) of diastematomyelia.

The MRI-features of diastematomyelia in a patient with unusually late onset of symptoms are reported. Direct visualization of the split cord and low conus on frontal MR-images was facilitated by three-dimensional Fourier transform (3-DFT) image acquisition.

Adult↗

Fluorinated psychopharmacological agents: noninvasive observation by fluorine-19 nuclear magnetic resonance.

Fluorinated psychopharmacological agents were measured with fluorine-19 nuclear magnetic resonance spectroscopy in the brain of intact rats that had been treated with fluphenazine. These in vivo experiments were compared to in vitro measurements of fluphenazine-treated rats. A high-field shift was observed in both in vivo and in vitro measurements. On the basis of the in vitro measurements, fluphenazine concentration in the brains of treated rats was estimated. Our observations demonstrate the feasibility of this technique for determining fluorinated neuroleptics in live mammals.

Animals↗

[Comparison of clinical findings and nuclear magnetic resonance tomography in syringohydromyelia and intramedullary tumors].

Magnetic resonance imaging allowed a distinct differentiation between syringohydromyelia (9 patients) and intramedullary tumour (2 patients). In syringohydromyelia the morphological evaluation showed a greater extension of the cavitation, especially in the caudal direction, than the estimation according to clinical findings. Tumours were visualised indirectly by changing the physiological shape of the spinal cord; therefore, small parts were not recognisable on magnetic resonance images but detected by the corresponding clinical symptoms. Clinical and morphological data were complementary and both necessary for a comprehensive appreciation of the pathological process.

Adolescent↗