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Biomedical subjects

F Doenz

Publications and source records attributed to F Doenz.

At least 19 recordsLinked to original sources

[CT-angiography of peripheral arterial diseases: principle and current indications].

Recent advances in multi-detector CT technology, improving the spatial resolution and the acquisition time, provide basis for CT-angiography of the abdominal aorta and peripheral vessels of the lower extremities. The objective of this review is to help the clinician to understand principle of CT-angiography of peripheral vessels and to provide an overview of the current clinical applications as well as the futures directions in diagnosis, treatment planning and post-therapeutic surveillance in peripheral vascular diseases.

Contrast Media↗

[Iliac vein compression syndrome, the "May Thurner Syndrome"].

The May Thurner Syndrome is a thrombosis of the left iliac vein due to the compression of the common iliac vein by the right common iliac artery. This results in intimal wall changes of the vein with secondary thrombosis. The treatment of choice is enovascular with thrombolysis followed by angioplasty with stenting.

Adult↗

[Management of critical limb ischemia].

Critical limb ischemia (CLI) is the leading cause of major leg amputation. Diabetes, smoking and end stage renal disease are the main risk factors for CLI. Despite their reduced survival rate, most CLI patients should be treated by surgical or endovascular arterial reconstruction, since amputation rate with conservative treatment alone is as high as 95% at 1 year in surviving patients with tissue loss, and can be reduced to 25% with successful reconstruction. When arterial reconstruction is impossible or fails, spinal cord stimulation also allows to avoid major amputation in up to 75% of precisely selected patients. Timely management and multidisciplinary approach are advised to reduce the risk of major amputation.

Humans↗

[Radiofrequency tumor ablation: from the liver to the lung passing by the kidney].

Tumor ablation using radiofrequency technique is an interventional radiology method for the treatment of liver renal or pulmonary tumors. The size of the lesion is the limiting factor of this technique. Tumors below 3 cm are treated with a 90% efficacy in one session. Complications are variable according to the organ treated.

Catheter Ablation↗

[Interventional neuroradiologic procedures].

Intracranial aneurysms, cervical carotid stenosis and acute cerebral ischemia constitute the three main and more frequent diseases in which the endovascular approach is considered a valuable alternative to the surgical or pharmacologic treatment. With the introduction of balloon assistance techniques, even intracranial large neck aneurysms can be currently suitable to endovascular treatment. Stent angioplasty is widely used in whole Europe in the treatment of cervical carotid artery stenosis. Mechanical endovascular embolectomy techniques are actually available to be used alone or in combination with pharmacologic thrombolysis in the treatment of acute cerebral ischemia. This article discuss on the new technical possibilities concerning the endovascular approach in these aforementioned diseases.

Aneurysm, Ruptured↗

[Non invasive multidetector CT angiography of coronary arteries: when and how should I do?].

Recent advances in multi-detector computed tomography technology offer a reliable tool for coronary arteries visualization and atherosclerotic plaque assessment. The objective of this article is to describe the principle of coronary angiography using multi-detector computed tomography, review the current diagnostic performances and help the reader to understand current applications and future challenges of multi-detector computed tomography in coronary artery disease diagnosis and management.

Coronary Angiography↗

[Liver anatomy: CT and MRI].

Computed tomography and magnetic resonance imaging are widely used tools to appreciate liver anatomy. Vascular and segmental anatomy are adequately appreciated with CT, while biliary anatomy is mainly seen with MR imaging. Basic principles of techniques and anatomical landmarks will be detailed.

Hepatic Veins↗

Life-threatening vascular complications after central venous catheter placement.

The purpose of this retrospective study was to report 11 cases of severe vascular complications after central venous catheter misplacement. For each patient, data collection included body mass index, the diagnosis at admission, the site of the procedure, the type of catheter, coagulation parameters, the imaging modalities performed and the applied treatment. Eight patients had a lesion of the subclavian artery. Brachiocephalic vein perforations were assessed in three more patients. All patients had a chest roentgenogram after the procedure, six a CT examination, and four an angiographic procedure. Seven patients had a body mass index above 30, and 5 patients had coagulation disorders prior to the procedure. Seven patients were conservatively managed, 2 patients died despite resuscitation, 1 patient was treated with a stent graft, and one by superselective embolization. Subclavian or jugular vein temporary catheter positioning is a practical approach. Identification of any iatrogenic perforation of the subclavian artery or central veins urges obtaining a chest roentgenogram and, when required, a chest CT, selective angiograms or venograms. Body mass index superior to 30, previous unsuccessful catheterization attempts, and coagulation factor depletion seemed to account for risk factors. Recognition of clinical and radiological complications is mandatory.

Adult↗

Combination of clinical and V/Q scan assessment for the diagnosis of pulmonary embolism: a 2-year outcome prospective study.

With the aim of evaluating the efficiency of our diagnostic approach in patients with suspected acute pulmonary embolism (PE), we prospectively studied 143 patients investigated by means of a ventilation/perfusion (V/Q) lung scan. A pre-test clinical probability of PE (Pclin) was assigned to all patients by the clinicians and scans were interpreted blinded to clinical assessment. A 2-year follow-up of our patients was systematically performed and possible in 134 cases. Distribution of clinical probabilities was high Pclin in 22.5%, intermediate Pclin in 24% and low Pclin in 53.5%, whereas the distribution of scan categories was high Pscan in 14%, intermediate Pscan in 18%, low Pscan in 57% and normal Pscan in 11%. The final prevalence of PE was 24.5%. High Pscan and normal Pscan were always conclusive (19 and 15 cases respectively). Low Pscan associated with low Pclin could exclude PE in 43/45 cases (96%). None of the patients in whom the diagnosis of PE was discarded had a major event related to PE during the 2-year follow-up. Overall, the combined assessment of clinical and scintigraphic probabilities allowed confirmation or exclusion of PE in 80% of subjects (107/134) and proved to be a valuable tool for selecting patients who needed pulmonary angiography, which was required in 20% of our patients (27/134).

Adult↗

Biodistribution of anti-CEA F(ab')2 fragments after intra-arterial and intravenous injection in patients with liver metastases due to colorectal carcinoma.

The biodistribution of simultaneous intra-arterial and intravenous injections of a radiolabelled anti-CEA MAb F(ab')2 fragment was studied in three patients with liver metastases from colorectal cancer. Identical MAb fragments, labelled with either 125I or 131I, were injected over a period of 30 min into the hepatic artery and into a peripheral vein. After 1 or 2 days, biodistribution was measured in the surgically removed metastases, normal tissue samples and blood. By tissue radioactivity counting, tumour uptake in the range 6.3-9.1% of injected dose per gram was found. Superimposable metastasis-to-blood and metastasis-to-normal liver ratios were obtained for both iodine isotopes in all three patients. The results indicate that the intra-arterial injection of MAb F(ab')2 fragments gives no measurable advantage over more convenient injections into a peripheral vein.

Antibodies, Monoclonal↗

Haemorrhage into the pancreatic duct (Hemosuccus pancreaticus): recognition and management.

OBJECTIVE: To highlight the clinical presentation, investigation and treatment of haemorrhage into the pancreatic duct. DESIGN: Retrospective study and review of publications. SETTING: University hospital, Switzerland. SUBJECTS: All 4 cases from 1972 to 1993. INTERVENTIONS: 2 Whipple procedures, 1 resection of the pancreatic head, 1 exploratory laparotomy. Radiological embolisation in one case. MAIN OUTCOME MEASURES: Cessation of haemorrhage and survival. RESULTS: The diagnosis was made preoperatively in three cases by gastroduodenoscopy and arteriography. Operation was the primary treatment in all patients and was effective with low morbidity and no mortality in three of them. Embolisation stopped the haemorrhage in the fourth patient, who was alcoholic and died of progressive liver insufficiency and variceal haemorrhage. CONCLUSIONS: There is no specific indication for haemorrhage into the pancreatic duct. The diagnosis is suggested by endoscopy (absence of a more common cause, or blood in the second part of the duodenum). Arteriography is essential to confirm the site of the bleeding and to attempt embolization. Operation is usually the definitive treatment.

Adult↗

["Standing waves": differential diagnosis of fibromuscular dysplasia].

We report two recent observations of an angiographic artefact called "standing waves". It results in the same characteristic beaded pictures than fibromuscular dysplasia. It is induced by the angiography catheter and is related to the speed of injection. The possible occurrence of this artefact should be borne in mind whenever the films show dysplastic lesions in more than one artery.

Adult↗

Design and testing of a high-flow autoperfusion catheter: an experimental study.

An autoperfusion catheter is similar to an angioplasty balloon catheter with side holes in the guide-wire lumen proximal to the balloon. When the balloon of the autoperfusion catheter is deployed and inflated in an artery, the guide wire is removed, and the hub of the guide-wire lumen is capped. The catheter then allows passive distal perfusion by using ambient pressure to drive blood into the guide-wire lumen, through the balloon, and out the end hole. This article discusses the requirements and constraints of a high-flow autoperfusion catheter, summarizes attempts to modify standard angioplasty catheters for use as an autoperfusion catheter, and describes the design and testing of a custom autoperfusion catheter capable of delivering approximately 3 mL/sec at physiologic pressures. In a model of canine acute renal artery occlusion lasting 90 minutes, the custom autoperfusion catheter provided marked protection from acute tubular necrosis compared with conventional percutaneous transluminal angioplasty catheters. The authors conclude that the high-flow autoperfusion catheter may be useful as a temporary stent in cases of rupture, dissection, or penetrating wounds involving large arteries.

Angioplasty, Balloon↗