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Biomedical subjects

M Forsting

Publications and source records attributed to M Forsting.

At least 109 records · Page 6Linked to original sources
PubMed1996

MR imaging of residual tumor tissue after transsphenoidal surgery of hormone-inactive pituitary macroadenomas: a prospective study.

22 patients were examined by magnetic resonance (MR) imaging before and after transsphenoidal surgery of hormone-inactive pituitary macroadenomas to evaluate for tumor removal. MR imaging was performed without and with gadolinium-DTPA before the operation and 3 months after. In all cases a suprasellar tumor extension was found preoperatively, in 9 cases with an additional parasellar, in 2 cases with an additional retrosellar extension (average diameter 2.5 cm). In 7 cases complete tumor removal was shown by postoperative MR, but in 11 cases residual tumor tissue was found (4 x suprasellar, 5 x parasellar, 2 x retrosellar). In 4 patients postoperative MR could not clearly differentiate residual tumor from scar formation. Although in cases of residual tumor follow-up MR imaging was performed over a period of two years, residual tumor volumes did not appear to change. This study demonstrates that MR imaging is highly sensitive for evaluating residual tumor tissue after transsphenoidal surgery of hormone-inactive macroadenomas.

Adenoma↗
PubMed1996

[High dosage administration of paramagnetic contrast media in diagnosis of focal brain lesions].

In analogy with high-dose contrast-enhanced CT, there have been a few studies during recent years that have dealt with high-dose paramagnetic contrast dyes in MRI. One reason for these studies was the development of new and low-osmolar contrast agents in the MR field. Depending on the clinical problem, a high-dose contrast study in MRI is rarely indicated: (1) in metastatic disease, MR imaging with high-dose contrast material is indicated when the standard dose study is negative or only shows a solitary cerebral lesion or a number of lesions just suitable for radiosurgery; (2) in patients with malignant glioma the high-dose study allows better definition of the tumor margins. If a radical surgical approach is planned, the diagnostic potential should be fully used; if only a biopsy or subtotal debulking is planned, a standard dose study is enough. (3) in patients with MS, a high-dose study is only recommended within therapeutic trials in which the number of active plaques is a primary variable.

Brain↗
PubMed1996

Three-dimensional computed display of otosurgical operation sites by spiral CT.

We studied the usefulness of spiral CT for preoperative information on the individual anatomy of the temporal bone in a computed three-dimensional (3D) display. In 87 patients with various otological diseases, 3D reconstructions were performed based on spiral high-resolution CT (HR-CT) by volume-rendering on an independent work-station. The positions of the ossicles, facial nerve, labyrinth and vestibular aqueduct relative to reference points were comprehensively demonstrated by thresholding or interactive segmentation. Spiral CT enables 3D display of otosurgical operation sites in a shorter scan time than conventional CT. 3D reconstructions improve the surgeon's understanding of individual anatomy and thus help in surgical planning. This is particularly important for surgery of temporal bone tumours, middle ear deformities, cochlear implants and saccotomy.

Ear Diseases↗
PubMed1996

[Does the administration of a high dose of a paramagnetic contrast medium (Gadovist) improve the diagnostic value of magnetic resonance tomography in glioblastomas?].

PURPOSE: To assess the efficacy of high-dose contrast enhanced magnetic resonance imaging (MRI) in detection and delineation of infiltrating tumour in glioblastoma. MATERIAL AND METHODS: In a phase II clinical trial 14 patients with suspected supratentorial glioblastoma underwent MRI with Gd-DO3A-butriol (Gadovist, Schering AG, Berlin) with doses of 0.1 up to 0.3 mmol/kg. RESULTS: Increasing the dose of Gd-DO3A-butriol resulted in improved enhancement (14/14) and better delineation of infiltrating tumour (9/14) up to 2 cm beyond enhancement after standard dose. In two of the 9 patients additional enhancement in the peritumoural oedema was only seen after the third injection. CONCLUSIONS: Successful surgery requires precise preoperative delineation of tumour borders. After high-dose MRI it might be possible to select those patients who would benefit from more radical attempts at eradicating the macroscopic as well as most of the microscopic compartment of glioblastoma.

Contrast Media↗
PubMed1996

Diagnostic value of spinal US: comparative study with MR imaging in pediatric patients.

PURPOSE: To assess the diagnostic value of spinal ultrasonography (US) in pediatric patients. MATERIALS AND METHODS: The findings on 38 spinal US scans in 30 patients (mean age, 5.5 months) were compared with those of corresponding magnetic resonance (MR) images. RESULTS: MR imaging showed a normal spinal canal in 14 of 38 examinations, a congenital anomaly in 22, and a neoplasm in two. In 32 of 38 examinations, US allowed exactly the same diagnosis as MR imaging. In five examinations, US depicted the main abnormality, but MR imaging revealed additional findings. In one examination, no consensus was achieved. Whenever US scans were normal, MR images also did not depict any spinal disorder. In all 24 examinations with abnormal MR findings, US enabled detection of the abnormality. CONCLUSION: Spinal US seems to represent a valuable diagnostic tool for congenital anomalies of the lower spine in infants and is recommended as the primary imaging modality in those patients.

Child↗
PubMed1996

Decompressive craniectomy in a rat model of "malignant" cerebral hemispheric stroke: experimental support for an aggressive therapeutic approach.

Acute ischemia in the complete territory of the carotid artery may lead to massive cerebral edema with raised intracranial pressure and progression to coma and death due to uncal, cingulate, or tonsillar herniation. Although clinical data suggest that patients benefit from undergoing decompressive surgery for acute ischemia, little data about the effect of this procedure on experimental ischemia are available. In this article the authors present results of an experimental study on the effects of decompressive craniectomy performed at various time points after endovascular middle cerebral artery (MCA) occlusion in rats. Focal cerebral ischemia was induced in 68 rats using an endovascular occlusion technique focused on the MCA. Decompressive craniectomy was performed in 48 animals (in groups of 12 rats each) 4, 12, 24, or 36 hours after vessel occlusion. Twenty animals (control group) were not treated by decompressive craniectomy. The authors used the infarct volume and neurological performance at Day 7 as study endpoints. Although the mortality rate in the untreated group was 35%, none of the animals treated by decompressive craniectomy died (mortality 0%). Neurological behavior was significantly better in all animals treated by decompressive craniectomy, regardless of whether they were treated early or late. Neurological behavior and infarction size were significantly better in animals treated very early by decompressive craniectomy (4 hours) after endovascular MCA occlusion (p < 0.01); surgery performed at later time points did not significantly reduce infarction size. The results suggest that use of decompressive craniectomy in treating cerebral ischemia reduces mortality and significantly improves outcome. If performed early after vessel occlusion, it also significantly reduces infarction size. By performing decompressive craniectomy neurosurgeons will play a major role in the management of stroke patients.

Animals↗
PubMed1996

Coil placement after clipping: endovascular treatment of incompletely clipped cerebral aneurysms. Report of two cases.

In up to 4% of patients whose aneurysms are microsurgically clipped, there is an expected or unexpected aneurysm residuum. The authors describe two patients in whom surgical clipping did not result in complete obliteration of the aneurysm sac and in whom a second operation was not believed to be the solution to the problem. In both patients complete occlusion of the aneurysm residuum was achieved via an endovascular approach. Using the Guglielmi detachable coil system, it was possible to place two platinum coils selectively into the aneurysms. The endovascular approach may be a good treatment option for all patients in whom surgical clipping does not result in complete obliteration of the aneurysm sac and reoperation is contraindicated or unacceptable to the patient.

Adult↗
PubMed1996

Spontaneous resolution of a large spinal epidural hematoma: case report.

Spontaneous spinal epidural hematoma is a rare condition that usually requires surgical evacuation of the hematoma. We report a case of spontaneous spinal epidural hematoma that was probably associated with aspirin intake. The initial clinical signs and symptoms included sharp, left-sided neck pain and weakness of the left arm. The initial magnetic resonance image showed a spinal epidural hematoma extending from C2 to C6, with compression of the myelon. This case is remarkable for dramatic clinical improvement within 12 hours and the magnetic resonance imaging documentation of complete resolution within 3 days. For each patient with a stable or improving neurological status, conservative management monitored by magnetic resonance imaging might be the treatment of choice.

Aged↗
PubMed1996

[Neuroradiological studies and findings in stroke].

This overview is about today's radiologic diagnostic possibilities in acute stroke. Despite many improvements in MR technology, CT is still the method of choice for most of these patients. Contrary to a long existing opinion, CT is a good diagnostic instrument even in the early phase of acute ischemic stroke. In combination with the new helical CT technique [CT angiography] all important questions regarding early therapeutic decisions can be answered. New MR perfusion techniques are just on the way to clinical application. Invasive angiography is only rarely indicated in acute ischemic stroke. The diagnosis of intracerebral hemorrhage is also mainly CT-based. MR and DSA are mandatory for further evaluation of the etiology of the hemorrhage. Nowadays, DSA is not longer mandatory for the diagnosis of cerebral venous sinus thrombosis. In some patients CT is already diagnostic; the combination of different MR and MRA techniques nearly always allows a definite diagnosis or exclusion of a venous thrombosis.

Brain Ischemia↗
PubMed1996

Anatomy of the temporal bone: detailed three-dimensional display based on image data from high-resolution helical CT: a preliminary report.

Our purpose was to demonstrate the application of helical computed tomography (CT) for computer graphics of the normal temporal bone with special regard to inner ear structures. Three-dimensional reconstruction of temporal bones was performed from helical CT data on 41 patients with various otologic diseases. Image postprocessing was carried out on an independent work station. In contrast to former surface-rendered three-dimensional visualizations of the temporal bone, a volumetric-rendering algorithm was used. This technique allows automated segmentation, thresholding, and simultaneous visualization of different planes (cube-cutting) in near-real time. We were able to demonstrate the three-dimensional display of the labyrinth during clinical routine. Anatomic details (internal auditory canal, cochlea, vestibulum, semicircular canals, distal part of the vestibular aqueduct, complete ossicular chain, fallopian canal, internal carotid canal) were comprehensively demonstrated by interactive segmentation or thresholding. Difficulties were found in three-dimensional delineation of the complete vestibular and cochlear aqueduct, as well as the modiolus. Initial experience with an advanced helical CT-based three-dimensional display showed excellent images of temporal bone anatomy. Validation studies with correlative histologic sections and surgical dissections remain to be done.

Ear, External↗
PubMed1996

[Radiology of lumbar spinal canal stenosis].

Lumbar spinal stenosis is a frequent cause of low back pain. In this paper we discuss both the pathophysiology and clinical symptomatology of the disease. We also discuss advantages and limitations of plain film radiography, myelography, CT and MRI in its diagnosis. Following an analysis of the pertinent literature we try to determine the relative merit of the various radiologic procedures as to their true representation of clinical and intraoperative findings and faithful rendition of postoperative results. Until sufficient statistically valid data regarding the clinical significance of radiological findings have accumulated, surgery of lumbar spinal stenosis can only be performed after critical evaluation of the individual case.

Diagnostic Imaging↗
PubMed1996

[Carotid TEA and perioperative thrombolysis: a new concept in therapy of acute ischemic stroke].

In seven carotid-related acute hemispheric strokes with simultaneous embolic occlusion of the middle cerebral artery thrombolysis with urocinase or rt-PA was performed preoperatively (n = 3) or intraoperatively (n = 4) after carotid endarterectomy. Four patients recovered totally, three patients showed a remarkable improvement and were able to walk postoperatively. The combination of carotid endarterectomy and thrombolysis (simultaneous or staged) is a new option in the emergency treatment of an acute carotid-related stroke and should be evaluated in prospective interdisciplinary studies.

Adult↗
PubMed1995

Rare diseases mimicking acute vertebrobasilar artery thrombosis.

Acute ischaemia of the vertebrobasilar circulation leads to a variety of clinical manifestation and is mostly due to cardiogenic or artery-to-artery embolism. We describe four neurological emergency situations involving vertebrobasilar artery aclusion of other origins; basilar migraine, extrinsic compression by rheumatoid inflammatory tissue, generalized vasculitis in subacute rheumatic fever and basilar artery dissection. The differential diagnosis of acute vertebrobasilar artery occlusion may have an important impact on patient management.

Acute Disease↗
PubMed1995

Combined microneurosurgical and endovascular "trapping-evacuation" technique for clipping proximal paraclinoidal aneurysms.

A method is described in which a combined endovascular and microneurosurgical approach is used for clipping aneurysms of the proximal paraclinoidal segment of the internal carotid artery. By temporary occlusion of the cervical carotid artery and continuously retrograde sucking of blood from the distal vessel via a double lumen ballon catheter, clip application to large and critically located aneurysms is facilitated applying decompression to the trapped arterial segment under intraoperative somatosensory-evoked potential (SEP) monitoring.

Journal Article↗
PubMed1995

Decompressive craniectomy for cerebral infarction. An experimental study in rats.

BACKGROUND AND PURPOSE: Acute ischemia in the territory of the carotid artery can lead to massive cerebral edema with raised intracranial pressure and progression to coma and death due to uncal, cingulate, or tonsillar herniation. Thus far, only anecdotal experience with supratentorial ischemia treated by decompressive craniectomy has been reported; and there are no published experimental data dealing with this kind of therapy in acute supratentorial stroke. In this study, we present our results on the effect of decompressive craniectomy in an endovascular model of cerebral infarction in rats. METHODS: Focal cerebral ischemia was induced in 50 rats using an endovascular occlusion technique of the middle cerebral artery. Decompressive craniectomy was performed in 30 animals: in 15 animals after 1 hour and in the remaining 15 animals 24 hours after vessel occlusion. Twenty animals were not treated by decompressive craniectomy (control group). RESULTS: Mortality in the nontreated group was 35%, whereas none of the animals treated by decompressive craniectomy died. Neurological behavior, weight loss, and infarction size were all significantly better in the animals treated by decompressive craniectomy, regardless of whether they had been treated after 1 or 24 hours (P < .01). CONCLUSIONS: Our results suggest that decompressive craniectomy for cerebral ischemia not only reduces mortality but also significantly improves outcome and reduces infarction size, probably because of increased perfusion pressure through leptomeningeal collaterals. This experimental study suggests that a controlled study of decompressive craniectomy in patients with acute internal carotid or middle cerebral artery occlusion would be worthwhile. By performing decompressive craniectomy in a small, selected group of patients, neurosurgeons may play an important role in the management of these patients.

Acute Disease↗