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Biomedical subjects

M Forsting

Publications and source records attributed to M Forsting.

142 records · Page 8Linked to original sources
PubMed1991

The spectrum of subcortical lesions in MRI, sensitivity and specificity.

Subcortical foci of increased signal intensity are frequently identified on MRI in the elderly. The lesions are compatible with various pathologic processes and MRI can only provide supportive data for a suspected diagnosis. Without the patient's clinical history the radiologist is not able to differentiate between real pathologic lesions and physiologic aging processes. The high sensitivity of MRI in detecting white matter lesions and the lack of specificity recommends an excellent teamwork between clinicians and radiologists.

Aged↗
PubMed1991

Hema and latex: a dangerous combination?

The endovascular treatment of intracranial aneurysms with detachable balloons requires filling materials that harden reliably and are compatible with the balloon. While the incompatibility of latex balloons and hema from different manufacturers is known, no incompatibility has been assumed thus far if both balloon and hema were from the same manufacturer. In two series of experiments, we filled a total of 20 latex balloons with hema as recommended by the balloon manufacturer. Within an observation time of 4 weeks all latex balloons ruptured. At the time of rupture, the balloons had gained 5-10% in weight, most likely due to osmotic shifts in water. Simultaneously, hardening of the hema resulted in a loss of elasticity of the latex. Until these compatibility problems are solved, silicone rather than latex balloons should be used with permanent filling materials such as hema for the endovascular treatment of intracranial aneurysms.

Embolization, Therapeutic↗
PubMed1990

[Intracranial MR flow signal changes in extracranial occlusions of the internal carotid artery].

Spin-echo sequences allow an identification of the basal brain vessels because of their typical signal void. The increasing use of MRI also in clarification of cerebrovascular disease requires a good knowledge of intracranial flow alterations. We saw characteristic signal pattern in the carotid siphon in 22 prospective examined patients with occlusion of the internal carotid artery confirmed by ultrasound. The lower siphon showed a loss of flow void and a brain isointense signal. The signal in the upper siphon was identical or showed a flow void with significant calibre reduction, probably because of collateral filling. This diagnostic potential of MRI is a remarkable advantage in comparison to CT and should be routinely considered in patients with cerebrovascular disease.

Arterial Occlusive Diseases↗
PubMed1990

[Nuclear magnetic resonance tomography follow-up in rapidly progressing central neurofibromatosis].

The rapidly progressing deficits of a patient with known central neurofibromatosis (NF) led to a MRI control scan. Contrary to the previous non-enhanced examinations we now saw multiple cerebral and spinal tumors, whose localisation and extension made surgical removal impossible. Gadolinium enhanced MRI is extremely useful in diagnosing and defining the extent of intracranial and intraspinal lesions, does not involve radiation exposure and should therefore be recommended generously in follow-up patients with known NF. This is the only feasible way to allow an early careful surgical removal of the tumors before reaching a point of no return.

Adult↗
PubMed1989

[How certain is the diagnosis of intracerebral tumor bleeding in magnetic resonance tomography?].

Three patients with intracerebral malignant tumours were examined with high-field strength MRI and CT to determine what differences might exist between a haemorrhagic tumour and a genuine intracerebral haemorrhage. Recent literature hint on characteristic signal abnormalities in comparison to pure intracerebral haematoma. However, two of our three patients showed no significant variation, in particular no delay in the evolution of methaemoglobin and no irregular haemosiderin deposition. Up to now the MRI does not seem to be the method of choice to evaluate the aetiology of intracerebral bleeding.

Adenocarcinoma↗
PubMed1986

[Acute spinal epidural abscess].

An acute spinal epidural abscess is a rare cause of paraplegia, seen in seven patients over a period of ten years. All patients had fever and severe localized back-pain. Unless treated, within hours or a few days, there will be root defects and rapidly progressive paraplegia. Staphylococcus is the most frequent causative organism and clinically manifest septicaemia is common. Rapid diagnosis and treatment are essential in deciding the patient's fate. Myelography is an important additional examination as it demonstrates the abscess in 96% of cases. Non-contrast radiology is of little value. High-dosage antibiotics and surgical spinal decompression are the cardinal treatment procedures. Antibiotics alone are justified only so long as there are no neurological deficits and neurosurgical intervention, if needed, is immediately available.

Abscess↗
PubMedDate not supplied

Perfusion-weighted MRI using gadobutrol as a contrast agent in a rat stroke model.

The purpose of this study was to examine the new nonionic contrast agent gadobutrol in MR perfusion-weighted imaging, including the influence of different concentrations and dosages of the agent on the sensitivity to perfusion alterations. Sixteen rats were examined within 35 to 105 minutes after endovascular occlusion of the middle cerebral artery. A fast T2*-weighted fast low-angle shot (FLASH) sequence was used to acquire four images before and 16 images after bolus injection of .1, .2, .3, and .4 mmol/kg gadobutrol as .5 molar and 1.0 molar formulation. From user-defined regions, we obtained the maximum signal decrease, the relative regional cerebral blood volume, and the bolus delay. Contrast between ischemic and nonischemic regions during bolus passage increased with dose and concentration of the contrast agent. For low doses (.1 and .2 mmol/kg), the ischemic lesion could not or could barely be discerned. For higher doses (.3 and .4 mmol/kg), administration of the 1 molar contrast agent yielded a better contrast between ischemic and nonischemic tissue. Our results suggest that administration of gadobutrol at higher dosage and higher concentration increases sensitivity to perfusion alterations. These results are potentially useful for perfusion-weighted imaging of the human brain, because the volume of contrast agent will be reduced if a solution with higher concentration is used. When using contrast agents in higher concentrations for human examinations, a significant signal decrease may be achieved also with the low doses (.1-.15 mmol/kg).

Animals↗
PubMedDate not supplied

Recurrent neurovascular hypertension: MR findings before and after surgical treatments.

A case of recurrent brain stem edema after surgical vascular decompression in a patient with neurogenic hypertension is presented. The surgical treatment resulted in occlusion of the left vertebral artery, stable blood pressure values, and no recurrence of the brain stem edema. MR imaging and MR angiography are excellent methods with which to assess patients suspected of having neurovascular hypertension, both before and after surgical treatment.

Adult↗
PubMedDate not supplied

Aneurysmal rupture during embolization with Guglielmi detachable coils: causes, management, and outcome.

BACKGROUND AND PURPOSE: Aneurysmal rupture during endovascular treatment is one of the most feared complications of endovascular aneurysm therapy. The purpose of this study was to determine the frequency, causes, management, and outcome of aneurysmal rupture that occurred during treatment with Guglielmi detachable coils (GDCs) in an unselected series of patients with ruptured cerebral aneurysms. METHODS: Between July 1997 and December 2000, we treated 164 acutely ruptured cerebral aneurysms with GDCs. All charts were reviewed, and patients with aneurysmal rupture occurring during embolization were identified. RESULTS: Five patients had an intraprocedural aneurysmal rupture. In one patient, rupture was due to guidewire perforation of the wall. In two patients, the microcatheter itself perforated the aneurysm. In another two patients, rupture occurred during placement of the first coil. Endovascular packing was continued in all patients. One patient died as a result of the aneurysmal rupture. No negative long-term effects were observed in the remaining four patients. In summary, we observed intraprocedural aneurysmal rupture in 3% of our patients, with a mortality rate of 20% and no long-term morbidity. CONCLUSION: Aneurysmal rupture during endovascular treatment with GDCs is a rare event; clinical severity may be variable. Embolization of the aneurysm can be continued in most cases, and most patients with treatment-related subarachnoid hemorrhage survive without serious sequelae.

Adult↗
PubMedDate not supplied

Cerebral perfusion alterations during the acute phase of experimental generalized status epilepticus: prediction of survival by using perfusion-weighted MR imaging and histopathology.

BACKGROUND AND PURPOSE: Persistent generalized status epilepticus (SE) is associated with alterations of cerebral perfusion (CP). Because perfusion-weighted MR imaging (PWI) allows noninvasive CP-determination, the aim of this study was to investigate CP alterations during acute experimental SE correlated with SE-induced neuronal cell loss. METHODS: The rat pilocarpine model was used to induce SE. Multilocal PWI was performed before (baseline) and 3, 15, 30, 60, and 120 minutes after onset of SE. Bolus-peak ratio (BPR) was calculated for the retrosplenial and piriform cortex, hippocampus, amygdala, and thalamus and compared with baseline. Neuronal cell loss was quantified at different time points after induction of SE by cresyle violet staining. RESULTS: Immediately after SE onset (3 minutes), BPR temporarily increased to 102%-130% in all regions, with a maximum in the amygdala (129 +/- 16%) and hippocampus (130 +/- 21%). At 15, 30, and 60 minutes, BPR decreased continuously to 57%-76%. BPR values <55% in the parietal and/or temporal cortex resulted in death. In surviving animals, BPR recovered to 66%-79% and there was a good correlation between neuronal cell loss in specific brain regions at 2 weeks after SE onset and maximal decrease in BPR (r > 0.73). CONCLUSION: PWI demonstrated a transient cerebral hyperperfusion immediately after SE onset, followed by a significant continuous decline to different perfusion levels. In our experimental setting, a decline of cortical BPR below 55% of baseline seems to be a prognostic threshold value associated with subsequent death. In surviving animals, there is good correlation between the maximal decrease in BPR in the acute phase of SE and late neuronal cell loss.

Acute Disease↗
PubMedDate not supplied

Extirpation of glioblastomas: MR and CT follow-up of residual tumor and regrowth patterns.

PURPOSE: To optimize the timing of CT and MR after glioblastoma resection and to define the pattern of tumor regrowth. SUBJECTS AND METHODS: Sixty-eight patients with glioblastoma were studied prospectively with CT and MR. The first postoperative scan was obtained between day 1 and day 5; follow-up scans were obtained bimonthly. RESULTS: Residual tumor was shown most reliably on scans obtained shortly after surgery (MR, 77%; CT, 40.5%). After the fourth day up to 3 months postoperatively, surgically induced enhancement prevented recognition of residual tumor. Seventy-five percent of patients with residual tumor shown by early postoperative MR had progressive disease during follow-up, whereas only 36% of patients without evidence of residual tumor had MR signs of progressive disease. CONCLUSION: Early, enhanced, postoperative MR is the radiologic procedure of choice to determine the extent of glioblastoma resection. Gross total tumor resection as determined by early postoperative MR correlates with a prolongation of life.

Brain Neoplasms↗
PubMedDate not supplied

Thrombolytic therapy in acute occlusion of the intracranial internal carotid artery bifurcation.

PURPOSE: To evaluate efficacy and clinical benefit of early thrombolytic therapy in intracranial internal carotid artery occlusion. METHODS: Thirty-two patients (mean age, 56 years) with acute intracranial internal carotid artery occlusion were studied clinically and with CT and angiography before and after thrombolytic therapy with intravenous alteplase (n = 16), superselective intraarterial alteplase (n = 8), and superselective intraarterial urokinase (n = 8). RESULTS: Initial CT showed a large parenchymal hypodensity in 11 (34%) patients, a small hypodensity in 15 (47%) patients, and no hypodensity in 6 (19%) patients. Recanalization after thrombolytic therapy was observed in 4 patients (12.5% in each treatment group). Follow-up CT showed six hemorrhagic infarcts and four parenchymal hematomas unrelated to recanalization, alteplase, or urokinase administration, but commonly associated with intraarterial treatment. Clinical outcome was fatal in 53%, poor in 31%, and moderate or good in 16% of the patients. Outcome was equal in different treatment groups and closely linked to both the quality of leptomeningeal collaterals and the extent of parenchymal hypodensity on the first CT. CONCLUSION: Because intravenous or intraarterial treatment with alteplase or urokinase fails to recanalize the vascular obstruction, it does not improve the prognosis of intracranial internal carotid artery occlusion over that of the natural course. Improved results may be possible with novel recanalization techniques.

Adult↗
PubMedDate not supplied

MR enhancement of brain lesions: increased contrast dose compared with magnetization transfer.

PURPOSE: To compare image contrast and lesion conspicuity of enhancing intracranial lesions obtained with T1-weighted and magnetization transfer T1-weighted spin-echo sequences after administration of standard (0.1 mmol/kg body weight) and triple doses of gadobutrol. METHODS: Twenty-four patients with a total of 34 enhancing intracranial lesions were studied with T1-weighted and magnetization transfer T1-weighted spin-echo MR imaging. An incremental dose technique was used with intravenous injections of 0.1 and 0.2 mmol/kg body weight gadobutrol. Lesion-to-white matter contrast and white matter-to-edema contrast were calculated. RESULTS: The lesion-to-white matter contrast of the magnetization transfer T1-weighted studies was significantly higher than that of the T1-weighted studies when identical doses of gadobutrol were compared. The lesion-to-white matter contrast was not significantly different on the triple-dose T1-weighted study and the standard-dose magnetization transfer T1-weighted study. Two lesions were visible only on the standard-dose magnetization transfer T1-weighted and the triple-dose studies. CONCLUSION: Standard-dose magnetization transfer T1-weighted and triple-dose T1-weighted spin-echo MR studies are equally well suited to increase the lesion-to-white matter contrast in patients with enhancing intracranial lesions. Triple-dose magnetization transfer T1-weighted studies further increase lesion-to-white matter contrast but do not show additional lesions.

Adult↗