Embolisation of a cystic lymphatic malformation of the neck.
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Biomedical subjects
Publications and source records attributed to P Vanhoenacker.
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Cervical spinal arteriovenous malformations and fistulas are rare but important entities because they are potentially curable. MRI and angiography are the most useful imaging modalities for the diagnosis. On contrast-enhanced CT imaging, they can mimic a tumor. A case report of cervical spinal arteriovenous malformation, initially believed to be a tumor, is presented.
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We describe a case of mucocele of the appendix, observed incidentally in a 42-year-old man. The plain film, ultrasound and CT features are reviewed. Adequate diagnosis and resection are important because of the risk of rupture and development of pseudomyxoma peritonei.
Aesthesioneuroblastoma is an uncommon tumour of the superior nasal cavity, originating from the olfactory mucosa. Usually no specific radiological features indicate the diagnosis; normally these tumours are seen on CT as homogeneous, enhancing, soft tissue masses causing bone remodelling. Typical but quite nonspecific MRI findings include high signal on T2-weighted images and strong enhancement after gadolinium. The extent of tumour in the paranasal sinuses and anterior cranial fossa is best assessed with MRI after intravenous gadolinium, and this is considered as the most accurate method for assessing preoperative resectability. We report an aesthesioneuroblastoma in an atypical location, with extensive calcification.
Selective and superselective renal embolization is a generally accepted technique for treating traumatic or iatrogenic renal arteriovenous fistulas or arteriocalyceal fistulas. Only a minority are pure arteriocalyceal fistulas. During embolization, an arteriovenous fistula may become a frankly bleeding arteriocalyceal fistula, causing massive haematuria and necessitating further embolization.
Flow in high-resistance peripheral vessels of the extremities is characterized by a short period of positive flow during systole and almost no flow during diastole. Hence, time-of-flight sequences for MR angiography in high-resistance peripheral vessels are successful only when applied in a plane perpendicular to the vessel course. When applied in a plane parallel to the vessel, the method suffers from the rapid saturation of the inflowing spins. Gadopentetate dimeglumine-polylysine is a new T1 relaxation agent with blood-pooling capability that can be used to prevent blood saturation. In the present study it produced excellent angiograms in rabbits at a dose of 0.01-0.08 mmol/kg injected IV. Time-of-flight angiograms were acquired in a 1.5-T superconducting magnet with a three-dimensional fast imaging with steady precession sequence, 20,40/10/20 degrees (TR/TE/flip angle), with an acquisition volume of 200 x 200 x 60 mm, 64 partitions, and velocity compensation in the slice-selection and frequency-encoding directions. Arteries and veins smaller than 1 mm were visualized over the entire length of the posterior limbs. If ongoing studies confirm the low toxicity of this new agent, gadopentetate dimeglumine-polylysine could offer a totally new approach to MR angiography.
Outpatient angiography of the abdominal aorta and the peripheral arteries of the under limbs was performed in 100 patients with complaints of peripheral vascular disease. In all patients small 5F catheters, a low-osmolar contrast medium and intraarterial digital subtraction angiography could reduce the local and general invasiveness of the angiographic procedure. Two complications occurred. In one patient thrombosis at the puncture site was noted. In another patient, an onset of angina pectoris was a minor and transitory complication. In 42 out of the 100 patients, treatment was conservative so that hospitalization could be avoided. With newer technical equipment angiography can be performed safely on an outpatient basis with important costsaving for the community. The late occurrence of some complications though, requires good information of the patient.
Magnetic resonance (MR) angiography is a rapidly evolving field in MR imaging, the main goal of which is a noninvasive tool for visualizing blood vessels. The acquisition of continuous images of the blood vessels, comparable to the conventional DSA images, as well as the functional evaluation of blood-flow velocities and flow patterns are the subject of continuing developments. The basic principles of the various techniques and their clinical applications are reviewed and the practical limitations in specific anatomic regions discussed. The review concludes with a survey of future developments.
Axial and sagittal proton density and T2-weighted MR images (TR 2,500-3,000 ms, TE 15-22 and 85-90 ms) were performed in 50 patients with multiple sclerosis (MS) on a 1.5 T superconductive system. The number of plaques on the axial and sagittal images in the periventricular white matter, the corpus callosum, the brain stem, the cerebellum, and the basal ganglia were counted separately by two independent observers. A total of 858 lesions (mean 17.40 +/- 21.57) were seen on the axial series and 1,196 (mean 24.32 +/- 26.22) on the sagittal scans. More lesions were visualized on sagittal images in the periventricular region (mean 18.79 +/- 21.69 versus 13.34 +/- 16.45; p less than 0.001) and the corpus callosum (mean 3.00 +/- 2.72 versus 0.57 +/- 1.19; p less than 0.001). In the brain stem more lesions were visualized on the axial images (mean 1.55 +/- 2.55 versus 0.87 +/- 1.20; p less than 0.05). In the cerebellum and basal ganglia, scans in the two planes were equivalent (p greater than 0.5). In three patients lesions were seen on the sagittal series, while the axial scans were normal. Sagittal T2-weighted images appear to demonstrate significantly more MS plaques than transverse images, especially in the periventricular region and the corpus callosum. This is explained by partial volume averaging, by the orientation of some cerebral structures (e.g., corpus callosum) with regard to the section plane, and by the longer diameter of the lesions in the axial plane.
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In a number of eukaryotic cell types, the promoter of the interleukin-6 (IL-6) gene is inducible by several agents. We studied this inducibility in two human (MG63 and HeLa H21) and four simian cell lines (BSC-1, AP8, CV-1 and VERO). Furthermore, we also investigated whether this inducibility was maintained when a heterologous gene was placed under control of the human IL-6 promoter. As a heterologous gene we used the Simian Virus 40 (SV40) large T antigen, because of its stimulatory effects on SV40-based expression vectors. For the human cell lines tested, we observed that this gene was equally well induced and controlled as the endogenous IL-6 gene. In contrast, the aforementioned simian cell lines were only slightly inducible for IL-6 production; moreover, after transfection with the IL-6 promoter--SV40 T antigen gene construct, a continuous, low level of expression was found, even in those lines which only showed a low (CV-1) or no (BSC-1) endogenous IL-6 background. This apparent difference between the human and simian cells analyzed does not reflect a species specificity, but presumably is related to a different differentiation state of these cells. Furthermore, the IL-6 gene induction could be correlated with activation of the required transcription factor NF-kappa B.