Biomedical subjects
Publications and source records attributed to K W Stock.
Langerhans cell histiocytosis includes three clinical forms of histiocytosis X. We describe a disseminated form of Langerhans cell histiocytosis (Letterer-Siwe disease) in monozygotic twins. The twins showed simultaneous onset of disease, almost identical clinical follow-up and findings on cranial CT. The cause of this phenomenon remains unknown.
RATIONALE AND OBJECTIVES: To introduce routine bilaterally antegrade selective stationary digital subtraction angiography (DSA), and prospectively compare it with unselective stationary DSA in the detection of calf arteries and assess additional time and complication rate. METHODS: Twenty-five patients received one unselective and two separate antegrade selective studies of each calf. Images were evaluated for image quality, number of depicted run-off vessels, and potential crural bypass recipient arteries. RESULTS: Bilaterally antegrade selective DSA was significantly superior in image quality and motion artifacts (P < 0.01). The number of adequately depicted run-off arteries per calf increased from 79% (2.37 of 3) to 96% (2.89 of 3) for legs with advanced peripheral vascular disease (PVD). Seventy-nine instead of 62 potential bypass recipients were identified (P = 0.002). Mean procedure time needed for selective catheterizations was 7 minutes. No adverse events were seen. CONCLUSIONS: Bilaterally antegrade selective DSA clearly is superior to aortic run-off DSA depicting tibial arteries. It requires comparatively small additional effort. Outflow vessel detection essentially is independent of advanced PVD.
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We describe three cases of acute disseminated encephalomyelitis (an immune-mediated inflammatory demyelinating disease of the central nervous system) and their histology, showing different radiological features. One appearance is a few ring-shaped enhancing lesions, which are found predominantly in the supratentorial white matter, the other is solid disseminated lesions.
PURPOSE: To evaluate the reliability of source images and maximum intensity projection images of MR angiography in showing the arterial segments of the circle of Willis. METHODS: In 62 patients, 526 arterial segments of the circle of Willis were determined to be present, partially present, or absent by blinded observers evaluating MR angiographic source images and maximum intensity projection images. Vessel diameter was measured on source images. These results were then compared with the results from intraarterial digital subtraction angiography. RESULTS: MR angiographic maximum intensity projection images had a sensitivity of 87% and a specificity of 88% and MR angiographic source images had a sensitivity of 89% and a specificity of 63% in depicting the presence of a vessel segment. The positive predictive value of an arterial segment with a diameter of at least 1 mm was 99%. CONCLUSION: MR angiography is a sensitive technique for detecting the anatomy of the circle of Willis. Maximum intensity projection images are more specific than source images. An arterial segment with a diameter of at least 1 mm on the source image is almost always present and patent.
BACKGROUND: Obstruction of the superior vena cava (SVC) in malignant disease can cause considerable distress to patients. Symptomatic relief can be achieved by the percutaneous implantation of a self-expanding stent (Wallstent) into the stenosis. METHODS: Fourteen patients with obstruction of the SVC were treated with one to three Wallstent endoprostheses. They suffered from advanced bronchogenic carcinoma (n = 12), thyroid carcinoma (n = 1), and breast carcinoma (n = 1). The indication for stent placement was symptomatic obstruction of the SVC and incurable disease. Stenting was performed for symptom relief, and before, during, and after courses of radiotherapy or chemotherapy as needed. RESULTS: Twelve patients experienced complete symptomatic relief within two days of stent placement. Two patients did not benefit. Three patients not given anticoagulation developed stent thrombosis between one week and eight months after initial placement, and within one day of endobronchial stent implantation with bronchial laser therapy or balloon dilatation in all three. Patency of the SVC was achieved again by a repeat procedure. CONCLUSIONS: Stent placement for obstruction of the SVC gives rapid symptomatic relief. Subsequent endobronchial stent implantation with bronchial laser therapy or balloon dilatation could be a risk for caval stent occlusion. Stent thrombosis remains a problem in patients who are not anticoagulated.
PURPOSE: To compare the reliability of magnetic resonance (MR) angiography performed with magnetization transfer suppression and variable flip angle excitation with that of intraarterial digital subtraction angiography (DSA) in imaging of the cerebral arteries. MATERIAL AND METHODS: Fifty nonconsecutive patients referred for intraarterial DSA gave informed consent to also undergo MR angiography of the intracranial arteries. RESULTS: MR angiography had a sensitivity of 100% and a specificity of 95% for detection of vessel occlusion (10 abnormalities). For detection of substantial vessel stenosis (seven abnormalities), sensitivity and specificity were both 86%; for detection of aneurysm (six abnormalities), sensitivity was 83% and specificity was 98%. Sensitivity and specificity were 100% for detection of arteriovenous malformation (three abnormalities), vessel displacement (three abnormalities), and extracranial-intracranial bypass (two abnormalities). MR angiography did not reliably demonstrate small feeding vessels of a tumor or faint residual perfusion of a thrombosed aneurysm. CONCLUSION: MR angiographic diagnosis of disease of the intracranial vasculature has high sensitivity and specificity but still is limited in comparison with intraarterial DSA.
Local therapeutic fibrinolysis is considered an efficient and established treatment for peripheral arterial occlusive disease. The introduction of newer fibrinolytics along with the development of interventional catheterization techniques have extended its use to previously untreated events such as cerebrovascular occlusions. Between 1989-1991 six patients with basilar and/or middle cerebral artery thrombosis were treated at the University Hospital, Basel, by superselective local intraarterial infusion of 400,000 U/h urokinase for 1-2 hours. Two of four patients with basilar artery occlusion showed complete remission one year after the intervention. The third showed no neurological improvement despite angiographic recanalization, and 48 h later suffered a fatal brainstem haemorrhage, while the fourth did not recover from coma and succumbed. Both patients with occlusion of the middle cerebral artery showed complete recanalization, but one had complete and the other partial neurological remission. Signs of slight systemic fibrinolysis were present but never attained the intensity of systemic therapeutic fibrinolysis as the antiplasmin and fibrinogen values showed. In summary, local therapeutic fibrinolysis contributes to the reduction of mortality and to remission of symptoms in occlusions of basilar artery, and offers some advantage in occlusions of the middle cerebral artery. A definite benefit from the latter will be proved only through large-scale randomized trials. The indication for local therapeutic fibrinolysis for thromboses of cerebral arteries requires a careful benefit-risk evaluation, an experienced angiography team and a special infrastructure for computed tomography and digital subtraction angiography.
We analysed the radiologically findings of 40 patients with histologically confirmed cerebral lymphoma but without AIDS in a retrospective study; 31 of these had primary cerebral lymphoma without any other manifestation of the disease. All patients had CT, 24 had angiography and in five patients MRT had been performed in addition. CT showed a solitary lesion in 60%, of these 62% had scalloped margins and 38% were nodular, 34% were isodense and 57% were hyperdense. Following contrast injection, there was increased density in 97% of the lesions. The most frequent localisation was in the region of the basal ganglia and the corpus callosum (33%), in the frontal lobes (30%) and in the temporal lobes (20%). Angiographically, 63% showed evidence of a space-occupying lesion, there were vascular irregularities in 33% and tumour contrast in 21%; in 25% of the patients angiography was normal. Early venous filling was not found in any case. T1 weighted sequences during MRT of 5 patients showed the tumour to be isointense or slightly hypointense. T2 weighted images showed the tumour to be hyperintense or with mixed signal intensities.
In suspicion of orbital fractures plain X-ray of the skull in half axial view are recommended. To be sure of this diagnosis one need to do examinations in high resolution computed tomography, axial and coronal view, in order to demonstrate the total extension of the fracture and lesions of the soft tissue of the orbit and of the surrounded areas. Magnetic resonance tomography is helpful in demonstrating fat and muscles around or in the fractures. There is no need to do other projections of plain skull X-rays except there is no computed tomography available.
MRA (magnetic resonance angiography) is besides duplex sonography at present the only noninvasive method for vascular visualisation. The technical fundamentals and our initial experiences with this new technique of angiography in the visualisation of the basilar artery are presented in the following article.
There is some evidence that a population of estrogen-receptive neurons exists in the preoptic/anterior hypothalamic area which uses gamma-aminobutyric acid (GABA) as neurotransmitter and which is involved in mediating the negative feedback of estrogens on pituitary luteinizing hormone (LH) secretion. These neurons are proposed to be presynaptic inhibitors to norepinephrine (NE) release thereby inhibiting the stimulatory effect of NE on LHRH neurons. Muscimol, a potent GABA agonist, inhibits pituitary LH release in ovariectomized rats after intraventricular injection of 5 nmol. This treatment significantly increased prolactin levels. Catecholamine turnover rates in micropunches of various hypothalamic and mesolimbic structures following intraventricular treatment with muscimol were determined using the method of blocking the activity of tyrosine hydroxylase by alpha-methyl-p-tyrosine. Muscimol did not affect catecholamine, GABA and glutamate concentrations. Turnover rates of NE were significantly reduced in the medial preoptic/anterior hypothalamic area. In this structure as well as in the nucleus accumbens and in the anterior mediobasal hypothalamus turnover rates of dopamine (DA) were also reduced whereas DA turnover in mediocortical amygdalae was increased by muscimol. The selective reduction of NE turnover following muscimol may be explained by a direct or indirect action of the GABA-eric drug on NE axon terminals. The reduced NE and DA turnover in the medial preoptic area may be causally related to reduced serum LH levels whereas the reduced hypothalamic DA turnover may explain increased blood prolactin levels.
PURPOSE: To assess the midterm results of closed reduction and percutaneous fixation (CRPF) with computed tomography (CT)-guided sacroiliac screw fixation in longitudinal posterior pelvic ring fractures. To document radiographic and CT follow-up patterns. METHODS: Thirteen patients with 15 fractures were treated. Eleven patients received a unilateral, two a bilateral, screw fixation. Twenty-seven screws were implanted. Continuous on-table traction was used in six cases. Mean radiological follow-up was 13 months. RESULTS: Twenty-five (93%) screws were placed correctly. There was no impingement of screws on neurovascular structures. Union occurred in 12 (80%), delayed union in 2 (13%), and nonunion in 1 of 15 (7%) fractures. There was one screw breakage and two axial dislocations. CONCLUSION: Sacroiliac CRPF of longitudinal fractures of the posterior pelvic ring is technically simple, minimally invasive, well localized, and stable. It should be done by an interventional/surgical team. CT is an excellent guiding modality. Closed reduction may be a problem and succeeds best when performed as early as possible.
PURPOSE: To report the results of thrombus fragmentation in combination with local fibrinolysis using recombinant human-tissue plasminogen activator (rtPA) in patients with massive pulmonary embolism. METHODS: Five patients with massive pulmonary embolism were treated with thrombus fragmentation followed by intrapulmonary injection of rtPA. Clot fragmentation was performed with a guidewire, angiographic catheter, and balloon catheter. Three patients had undergone recent surgery; one of them received a reduced dosage of rtPA. RESULTS: All patients survived and showed clinical improvement with a resultant significant (p < 0.05) decrease in the pulmonary blood pressure (mean systolic pulmonary blood pressure before treatment, 49 mmHg; 4 hr after treatment, 28 mmHg). Angiographic follow-up in three patients revealed a decrease in thrombus material and an increase in pulmonary perfusion. Two patients developed retroperitoneal hematomas requiring transfusion. CONCLUSION: Clot fragmentation and local fibrinolysis with rtPA was an effective therapy for massive pulmonary embolism. Bleeding at the puncture site was a frequent complication.
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