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T Hagen

Publications and source records attributed to T Hagen.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Diffusion-weighted magnetic resonance imaging in the diagnosis of cerebral infarct].

Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis. DWI is superior to T2WI in assessment of small cortical infarcts and cerebral infarction in patients with preexisting vascular lesions. DWI is not specific, so other causes like cerebral hematoma and encephalitis have to be considered.

Adult↗
PubMed1997

[Perfusion-MRI in cerebral infarct].

PURPOSE: To investigate the hemodynamic changes in patients with acute cerebral stroke by perfusion MRI. MATERIAL AND METHODS: In 12 patients with acute stroke in the territory of the middle cerebral artery, perfusion MRI was performed. Peak time, mean transit time, regional cerebral blood volume and regional cerebral blood flow were calculated in the infarction, the peri-infarction area and the contralateral hemisphere. RESULTS: In the infarction the mean blood flow was 29 ml/100 g/min, compared to about 40 ml/100 g/min in the peri-infarction area and the contralateral hemisphere. In two patients increased cortical blood flow was found in the infarction due to luxury perfusion. The cerebral blood volume was reduced in the infarction, but significantly increased, to 7.3 ml/100 g, in the peri-infarction tissue. CONCLUSION: Perfusion MRI allows one to differentiate various patterns of perfusion disorders in patients with acute cerebral stroke. The resulting data may be helpful in describing the pathophysiologic mechanisms of compensation.

Acute Disease↗
PubMed1997

Stereotactic neurosurgery planning with 3-D spiral CT-angiography.

OBJECTIVE: To assess the feasibility and value of spiral CT angiography of the brain vessels for the planning of neurosurgical stereotactic interventions. MATERIAL AND METHODS: Fourty-two patients harboring cerebral lesions underwent spiral CT angiography prior to stereotactic biopsy. Thin spiral CT slices with a collimator slice thickness of 1 mm and a pitch of 1 were used. Multiplanar reconstructions and maximum intensity projections (MIP) were obtained as well as 3-D tissue definition. RESULTS: There was a sufficient visualization of vessels and of their relationship to the lesion. Tumor neovascularization was clearly demonstrated. Arteries could be shown separately. Stereotactic coordinates of targets were chosen at a safe distance from the vessels and the simulation of tarjectories using the cine loop was made possible. In three cases the presence of a pathological vascularization warned against a stereotactic biopsy. CONCLUSION: Spiral CT angiography seems to yield enough topographical information for the accurate planning of stereotactic surgery for brain lesions. CT angiography with the helical technique is rapid and less invasive than digital subtraction angiography.

Adolescent↗
PubMed1997

Patient doses from standard and spiral CT of the head using a fast twin-beam system.

Investigations were carried out on a novel type of CT scanner, the Elscint CT-Twin, for comparison and optimization of the patient dose caused by standard and spiral CT of the head. For selected CT parameters, organ doses of the Alderson head phantom were measured with thermoluminescent dosemeters. Organ doses were also calculated using the normalized computed tomography dose index (CTDIn) combined with organ dose conversion factors. Then effective doses were deduced. For standard and spiral head CT examinations brain, red bone marrow and bone surface receive the main contributions to effective dose. This amounts to 0.9 and 0.8 mSv for routine standard and spiral CT, respectively, if the combination "dual-slice" mode, 250 mAs per rotation, 5 mm nominal slice width and a packing factor of 1.0, is applied. In clinical practice, for spiral CT head examinations the effective dose has been reduced to 0.7 mSv while guaranteeing adequate image quality, as assessed by determination of low and high contrast resolution. The effective dose values obtained are in the lower part of the range of values published in the literature. The dose determinations showed that, from the aspect of radiation protection of the patient, CT examinations with nominal slice widths between 0.5 and 1 mm as well as packing factors greater than 1.0 should be restricted to really necessary cases.

Head↗
PubMed1997

Multiple cerebral aneurysms in identical twins.

We report the finding of multiple cerebral aneurysms in a pair of identical twins. One twin had subarachnoid hemorrhage and intracerebral hematoma; her sister had subarachnoid hemorrhage and intraventricular bleeding. Angiography in both cases showed multiple cerebral aneurysms. It is appropriate to recommend a cerebral angiographic examination of an asymptomatic twin after the other twin has suffered an aneurysmal subarachnoid hemorrhage.

Adult↗
PubMed1996

[Value of CT-angiography in diagnosis of cerebral sinus and venous thromboses].

Dural sinus thrombosis is not uncommon. Due to the nonspecific symptomatology, as well as the manifold etiology, clinical diagnosis may be difficult. In these cases imaging procedures are frequently crucial in deciding how to proceed and how to treat. The aim of our study was to evaluate the diagnostic utility of helical CT in the detection of dural sinus thrombosis. In 20 patients with clinically suspected thrombosis CT angiography was performed. In 6 patients dural sinus thrombosis was diagnosed. In order to acquire also arterial vessels, a short delay of about 22 s after the onset of the application of contrast medium was selected. By this method we found an occlusion of the MCA in two patients with clinically suspected sinus thrombosis. In all patients the transverse slices and the multiplanar reconstructions showed filling defects or an "empty delta" sign. With irregular outlines the thrombus could be depicted over the complete course of the sinus. The MIP reconstructions were particularly helpful in the evaluation of the vessel anatomy and the pathological collateral venous drainage. In three patients MR angiograms were available for comparison. The smaller veins, such as the v. vermis inferior, were less clearly depicted than in CT angiography. CT angiography is a fast and reliable method to exclude or verify a sinus thrombosis. It can be performed immediately after non-enhanced CT. According to our present experience CT angiography is sufficient for the diagnosis of a sinus thrombosis.

Adolescent↗
PubMed1996

[CT-angiography in planning stereotaxic biopsies].

Twenty-one patients referred for stereotactic biopsy were studied by CT angiography. Helical CT with 1 mm collimation was obtained (pitch of 1:1). Multiplanar reconstructions were performed; maximum intensity projections and shaded-surface displays were generated by connectivity-based editing tools. The visualization of cerebral vessels was excellent. No further conventional angiography was needed. Improved information was obtained about localization of the intracranial lesion and its relationship to neighboring vessels. No bleeding complications were detected by CT after stereotactic biopsy.

Adult↗
PubMed1996

[Incidence of postmyelography syndrome and postmyelography complaints after lumbar puncture with the Sprotte pencil-like needle in comparison with the Quincke needle].

PURPOSE: Myelography in combination with a postmyelography CT is an important presurgical examination because of its excellent visualisation of the disc, the bone and the contrast-filled dura. Side effects after myelography can be observed in up to 50% of patients. The pathophysiological mechanism is thought to be increased cerebrospinal fluid leakage at the puncture site. Since the introduction by Sprotte in 1979 of the pencil-point needle, a modification of Whitacre's needle, fewer complaints after lumbar puncture have been reported. The aim of the study was to examine the influence of two types of needle points and the temperature (37 degrees C vs 21 degrees C) of the contrast medium (CM; iotrolan, Isovist) on the incidence of side effects of lumbar puncture for myelography. MATERIAL AND METHODS: In a prospective randomized trial the incidence of complaints after lumbar puncture with intrathecal CM application was evaluated by the use of a 21-G pencil-point needle as modified by Sprotte compared to our usual 22-G needle with a Quincke bevel. Some 412 patients (201 female, 211 male; mean age 54.05 +/- 7.4 years) were investigated. Directly after examination and 1. 3 and 5 days later the patients were questioned about complaints (headache, neck stiffness nausea, vomiting, buzzing in the ear and dizziness). The results were tested by the chi square test. RESULTS: A significantly lower incidence of complaints was seen after lumbar puncture with the pencil-point needle/Quincke needle (headache: 6.3%/18.9%, P < 0.0001; headache lasting 3 days: 0.5%/7.8%, P < 0.0001; headache lasting 5 days: 0%/2.4%, P = 0.0305; nausea: 0%/4.9%, P = 0.0009; vomiting: 0%/3.4%, P = 0.0009; dizziness: 0%/3.4%, P = 0.0074; neck stiffness: 0%/3.4%, P = 0.0074). The temperature of the CM had no influence on the complaints. No influence was seen on the quality of the myelogram. No relation to sex and age was found. CONCLUSION: Complaints after lumbar puncture and myelography are caused by the cerebrospinal fluid leakage at the puncture site. The incidence of side effects related to this leakage can be reduced by using a pencil-point needle. The temperature of the CM has no influence on the complaints.

Adolescent↗
PubMed1996

A study of dose reduction using digital luminescence radiography for lateral skull radiography.

For lateral skull radiography the minimum required radiation patient exposure to ensure adequate image quality was determined for digital luminescence radiography (DLR) in comparison with a screen-film system (speed class 200). Radiographs were produced with a grid technique on conventional X-ray equipment. A real prepared female head including a true fracture above the pars petrosa ossis temporalis was imaged. The tube current-time product (mAs), and thus the surface entrance dose, was varied systematically. Surface entrance dose was measured with TLD-100 rods. Image quality was judged by experienced radiologists according to the criteria: visual resolution, mean optical density, contrast and perceptibility of specific bone structures. Surface entrance dose was reduced from 0.46 to 0.20 mGy by application of DLR instead of speed class 200 screen-film system without loss of diagnostic information in clinical routine. This corresponds to a dose reduction potential of 57% showing a good agreement with the dose reduction potential of 52% obtained in a previous study using the Alderson head phantom.

Female↗
PubMed1996

The central sulcal vein: a landmark for identification of the central sulcus using functional magnetic resonance imaging.

The authors evaluated the anatomical location of the central sulcus (CS) in 24 cerebral hemispheres (eight in which tumors were located centrally, 16 in controls) using: 1) classic anatomical landmarks seen on magnetic resonance (MR) imaging (24 hemispheres); 2) functional MR imaging (24 hemispheres); and 3) intraoperative electrical stimulation mapping (eight hemispheres). On MR imaging the CS was identified with certainty in 79% of hemispheres (four of eight in patients, 15 of 16 in controls). Functional MR imaging identified a parenchymal "motor hand area" in only 83% (20 of 24 hemispheres; five of eight in patients, 15 of 16 in controls); this area was located in the precentral gyrus in 16 (80%) of 20, additionally in the postcentral gyrus in 10 (50%) of 20, and exclusively in the postcentral gyrus in four (20%) of 20. In contrast, functional MR imaging detected one to three sulcal veins presumably draining blood from the adjacent motor hand area in 100% (24 of 24) of the hemispheres studied, and anatomical MR imaging and intraoperative mapping localized these veins in the CS. It is concluded that sulcal veins lying deep within the CS: 1) drain activated blood from the adjacent pre- or postcentral cortex during performance of a motor hand task; 2) can be identified easily with functional MR imaging; and 3) are an anatomical landmark for noninvasive identification of the CS and thus the sensorimotor strip. The detection of these veins provides a more consistent landmark than the detection of parenchymal motor areas by functional MR imaging; this technique may be used when classic anatomical landmarks fail to identify the sensorimotor strip.

Adult↗
PubMed1995

[Chemotherapy-induced hemolytic uremic syndrome. A complication to mitomycin treatment of breast carcinoma].

Mitomycin is a cytotoxic antibiotic that was first introduced into clinical use in 1958. Not until twenty years later was it recognised that haemolytic uremic syndrome could develop after treatment with mitomycin. It can be asked whether this condition was undiagnosed in previous years, since its frequency is now reported to be 4-15%. The disease appears to be dose-related, since it rarely occurs in patients who have received mitomycin < 30 mg/m2. No effective therapy has been established. We describe two patients with breast cancer in remission after treatment with mitomycin in combination with 5-fluorouracil. Both developed haemolytic uremic syndrome with fatal outcome.

Adult↗
PubMed1995

Intramitochondrial protein synthesis is regulated by matrix adenine nucleotide content and requires calcium.

The hypothesis that fluctuations in matrix adenine nucleotide content (ATP + ADP + AMP) may regulate intramitochondrial protein synthesis was investigated in newborn and adult rat liver mitochondria. Protein synthesis in mitochondria from 0-h-old newborns, which contain 3.4 +/- 0.3 nmol adenine nucleotide/mg protein, was > 90% lower than protein synthesis in mitochondria from 4-h-old newborns, which contain 9.1 +/- 0.2 nmol adenine nucleotide/mg protein. If 0-h newborn mitochondria were preincubated to accumulate adenine nucleotides to 16.8 nmol/mg protein in vitro, the protein synthesis rate increased 25-fold compared to control. Adult rat liver mitochondria normally contain 12-14 nmol adenine nucleotide/mg protein and exhibit a brisk rate of protein synthesis. Following a preincubation to deplete adenine nucleotides in vitro down to 3 nmol/mg protein, protein synthesis in adult liver mitochondria was nearly abolished. Conversely, when adult mitochondria were preincubated to superload adenine nucleotides (to 29 nmol/mg protein), the rate of protein synthesis was doubled. Protein synthesis was also inhibited when the matrix ATP/ADP ratio was lowered by adding FCCP or by omitting phosphate. In adult mitochondria, protein synthesis was inhibited by 0.5 mM EGTA and was increased in proportion to buffered free calcium between 0 and 20 microM. The rate of intramitochondrial RNA synthesis was not inhibited by EGTA nor affected by variations in matrix adenine nucleotide content. The results show that intramitochondrial translation requires matrix calcium and is regulated by changes in the matrix adenine nucleotide content that affect the matrix ATP concentration. The matrix adenine nucleotide content is controlled by the ATP-Mg/Pi carrier. In newborns, the matrix adenine nucleotide content increases 3-fold within 2-4 h after birth, stimulating mitochondrial translation 10-fold and probably contributing to the onset of postnatal mitochondrial biogenesis and adaptation to aerobic metabolism.

Adenine Nucleotides↗
PubMed1995

Hyperglycemia and hemorrhagic transformation of cerebral infarcts.

BACKGROUND: Identification of factors that predispose to bleeding into ischemic brain could lead to safer use of thrombolytic agents in the setting of ischemic stroke. Recently de Courten-Meyers and colleagues reported that occluding the middle cerebral artery of markedly hyperglycemic cats was associated with 5-fold more frequent and 25-fold more extensive hemorrhage into infarcts than in normoglycemic animals. Hemorrhage associated with hyperglycemia in cats was much more pronounced with reperfusion than with permanent middle cerebral artery occlusion. CASE DESCRIPTION: We describe two patients with a unique presentation of diffuse hemorrhagic infarction of the caudate and lentiform nuclei associated with initially marked hyperglycemia and the subsequent development of hemichorea. CONCLUSIONS: We hypothesize that the marked hyperglycemia due to poor control of diabetes contributed to the hemorrhagic change of the caudate and lenticular nuclei. Because the hemorrhage in hyperglycemic cats was more pronounced in the setting of reperfusion, hemorrhagic risk associated with hyperglycemia should be investigated, particularly in ongoing thrombolytic treatment trials for acute ischemic stroke. We encourage other acute stroke investigators to prospectively look at the risk of brain hemorrhage in stroke patients with marked hyperglycemia.

Aged↗
PubMed1995

[Correlation of preoperative neuroradiologic with postoperative histologic diagnosis in pathological intracranial processes].

PURPOSE: To determine the accuracy of preoperative neuroradiological diagnosis of pathological intracranial processes in a prospective study. MATERIALS AND METHODS: A team of three neuroradiologists determined the diagnosis in CT, MR and angiography prior to stereotactic biopsy or operative resection (173 patients). Only one diagnosis was allowed, except in those cases with two equally probable diagnosis (24 patients). In 106 patients a resection of a brain tumor, in 67 cases a stereotactic biopsy was performed. According to the histological diagnosis the patients were subdivided into three groups: 1: complete agreement: the single diagnosis was correct. 2: conditional agreement: on of the 2 differential diagnosis was correct. 3: no agreement RESULTS: In 131 cases (76%) a complete agreement, in 24 cases (14%) a conditional agreement and in 18 patients (10%) no agreement were found. Assuming only stereotactic procedures the neuroradiological diagnosis was correct in 44 cases (66%) and incorrect in 10 cases (15%). In 13 patients (19%) one of the two differential diagnosis was correct. The specificity of the major tumors was calculated between 92% and 100%. The sensitivity for pituitary adenomas (n = 9) and neurinomas (n = 11) was 100%, the sensitivity for meningiomas (n = 32) was 94%. A sensitivity was calculated between 50% and 71% for astrocytomas (WHO I to WHO IV, n = 64) and metastases (n = 24). CONCLUSION: The accuracy was found to be higher than in the comparable retrospective studies.

Adolescent↗
PubMed1995

[Brain metastases of bronchial and breast carcinoma. Differences in metastatic behavior and prognosis].

Evaluation of 135 cases with brain metastases from non-small-cell lung cancer (group 1) compared with 51 cases from small-cell lung cancer (group 2) and 56 cases from breast cancer (group 3) showed that the frequency of solitary metastases was significantly higher in group 1 and 3. However, in group 2 lesions without surrounding edema occurred more frequently. The rate of patients with extracerebral metastases was significantly higher in groups 2 and 3. The longest median interval between primary tumor and brain metastases was observed in breast cancer patients. The highest local remission rate was seen in small-cell lung cancer if patients who received whole-brain irradiation of 30 Gy alone were compared (63% vs 45% in group 1 and 52% in group 3). However, with regard to clinical course no significant differences were recorded. Survival of lung cancer cases was similar, whereas breast cancer cases survived significantly longer, both after radiotherapy alone and after surgery plus radiotherapy. This might be caused by differences in the natural course of the two diseases as well as adjuvant treatment modalities like hormone and chemotherapy. In conclusion, because long-term survivors were observed only in the breast cancer group, these patients probably have the highest chance of profiting from a locally aggressive treatment approach.

Adult↗
PubMed1995

[Creutzfeldt-Jakob disease. What is the role of MR tomography?].

Creutzfeldt-Jakob disease (CJD) is a rare, but fatal and transmissible brain disease. The clinical diagnosis is based upon progressing dementia, myoclonic jerks and characteristic EEG changes, but it is difficult to diagnose and not only in the early phase of the disease. Cerebral biopsy is reserve for individual selected cases and contested because of the danger of contamination from instruments and potential transmission. We report three patients with histologically confirmed CJD and confirm that MRI is a valuable tool for the diagnosis of this disease.

Biopsy↗