Biomedical subjects

A Scheule

Publications and source records attributed to A Scheule.

3 recordsLinked to original sources

PubMed2006

[Cardiovascular whole-body MR imaging in patients with symptomatic peripheral arterial occlusive disease].

PURPOSE: To examine patients with peripheral-arterial-occlusive-disease (PAOD) for systemic effects associated with atherosclerosis using a comprehensive state-of-the-art whole-body MR examination protocol. The protocol comprises the assessment of the complete arterial vasculature (except coronary arteries), the brain, and the heart. MATERIALS AND METHODS: Multi-station whole-body 3D MR angiography was performed in sixty consecutive patients with clinical suspicion for PAOD at 1.5 T (Magnetom Avanto, Siemens, Erlangen, Germany). Functional and delayed enhancement cardiac images were acquired, as well as FLAIR images of the brain and TOF angiography of intracranial vessels. MR and DSA images were assessed by independent observers for atherosclerotic manifestations and other pathology. Sensitivity and specificity for the detection of vascular pathology was calculated for MR data using conventional DSA of the symptomatic region as standard-of-reference. RESULTS: Sensitivity and specificity for the detection of significant vascular stenosis (> 70 % luminal narrowing) was 94 % and 96 % (PPV 87 %, NPV 98 %). Significant microangiopathic tissue alterations (n = 7) and/or cerebral infarction (n = 18) were diagnosed in 23/60 patients. Thirty-eight of 60 patients presented with systolic left ventricular wall motion abnormalities. In 24 patients subendocardial or transmural delayed enhancement was detected in corresponding regions, indicating prior myocardial infarction. CONCLUSION: For patients with PAOD and suspected systemic atherosclerotic disease a comprehensive diagnosis of accompanying cardiovascular pathology and therefore staging of systemic atherosclerotic disease is feasible within one MR examination.

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PubMed1997

Influence of the perfusate temperature on lung preservation: is there an optimum?

The optimal temperature of the pulmonary flush perfusate is still a matter of controversy. At present, a temperature of 10 degrees C is favored. This study deals with the structural and functional impact of different perfusate temperatures on lung preservation. In an extracorporeal rat heart-lung model lungs were preserved with Perfadex solution of 4, 15 and 25 degrees C and submitted to 2 h ischemia. Heart-lung blocks harvested from male rats were perfused with Krebs-Henseleit solution and ventilated with room air. Lungs were perfused with deoxygenated perfusate via the working right ventricle while the coronary arteries were retrogradely perfused with oxygenated perfusate. Oxygenation capacity (dPO2), peak inspiratory pressure (PIP) and pulmonary vascular resistance were measured. After establishment of baseline functional parameters hearts were arrested with 10 ml St. Thomas cardioplegia and lungs were flushed with 20 ml Perfadex solution. The heart-lung block was then stored for 2 h at 10 degrees C. Reperfusion was performed thereafter under the same conditions. At the end of the trial the lung tissue water was measured by the wet/dry ratio. The perfusion time of the groups flushed with 15 or 25 degrees C perfusate was significantly lower than that of the 4 degrees C group. After 20 min reperfusion dPO2 of the groups flushed with 15 or 25 degrees C was superior to those submitted to a 4 degrees C flush perfusion. PIP was significantly lower in the 15 degrees C group than in the 4 and 25 degrees C groups. The wet/dry ratio revealed the smallest water content in the 15 degrees C group. We conclude that the post-ischemic lung function is dependent on the temperature of the flush perfusate. Among the tested temperatures, perfusion at 15 degrees C showed the best results. The optimum may therefore lie in this range.

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PubMed1997

Potassium-reduced lung preservation solutions: a screening study.

In recent years several potassium-reduced solutions have been developed for improvement of pulmonary preservation. A comparison of these solutions in a single study, however, has not yet been performed. In an extracorporeal working rat heart-lung model (n = 7/group) lungs were preserved with 20 ml Euro-Collins (EC), low potassium EC (LPEC), low potassium 2% dextran (LPD), ET-Kyoto (ETK) or low potassium 5% dextran (Perfadex) solution, while hearts were arrested with 10 ml St. Thomas' cardioplegia. Lungs of controls were not perfused. The heart-lung blocks were stored for 2 h at 10 degrees C. Thereafter, heart-lung blocks were extracorporeally perfused with Krebs-Henseleit solution with washed bovine red blood cells. Coronaries were perfused with oxygenated perfusate. Lungs were perfused via the working right ventricle with deoxygenated perfusate and ventilated with room air. Oxygenation capacity (dPO2) and pulmonary vascular resistance (PVR) were measured. Reperfusion/ventilation was performed for 40 min. At the end of the experiment the wet to dry (W/D) ratio of lungs and light microscopic assessment of the degree of edema (0-4) were performed. All potassium-reduced solutions showed superior dPO2 and a lower PVR than EC and controls while LPEC exhibited the most stable dPO2 and lowest PVR after 30 min reperfusion. The W/D ratio of all potassium-reduced groups was lower than the ratio of EC and controls. In LPEC, ETK and Perfadex the least degree of edema was noted. All solutions used in this study are superior to regular EC. However, when compared directly, LPEC perfused lungs showed better functional preservation than all other alternative solutions.

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