ABSTRACT
BACKGROUND: The aim of this single-center combined prospective/retrospective cohort study was to analyze Gadolinium (Gd)-enhanced MRA (magnetic resonance angiography) and MRV (MR venography) for the diagnosis of pulmonary artery embolism and deep venous thrombosis. The gold standard methods result in major exposure to radiation and a high amount of nephrotoxic iodinated contrast media. This is the first larger contrast-enhanced MR imaging study of acute and chronic venous thromboembolic disease of various stages. METHODS: We prospectively examined 88 patients presenting clinical signs of deep vein thrombosis and/or pulmonary artery embolism. A single-session, one-stop shop Gd-enhanced MRA/MRV at 1.5 Tesla, using gradient echo sequences with very short repetition and echo times as well as low flip angles with subtraction and three-dimensional reconstruction, was performed. A diagnosis was made with the consensus of two experienced radiologists. RESULTS: We observed excellent MRA image quality in 87% and even higher diagnostic image quality of MRV in 90% of our examinations. Pulmonary artery embolism occurred with deep vein thrombosis in 22%. CONCLUSIONS: Gd-enhanced MRA/MRV provided excellent image quality for the diagnosis of venous thromboembolic disease in the majority of cases. It may be particularly useful to plan and follow-up filter implantation and retrieval in the inferior caval vein.
ABSTRACT
BACKGROUND AND AIM OF THE STUDY: Increased concentrations of glutaraldehyde (GA), diamine-extension (DA) of crosslinks and subsequent extraction of excess GA all reduce bioprosthetic calcification in the subdermal rat model. The study aim was to demonstrate the combined effect of all three treatments in a circulatory sheep model. METHODS: Two fixation treatments were used for GA detoxification (urazole in acetate buffer, 0.1 M; pH 4.5; 37 degrees C; 7 days): (i) conventional 0.2% GA fixation (4 degrees C; 7 days); and (ii) enhanced 3.0% GA fixation (4 degrees C; 2 days, followed by a DA interim step; 100 mM L-lysine; 37 degrees C; 2 days, followed by GA; 3.0%; 37 degrees C; 5 days). Entire porcine root prostheses were implanted in the distal aortic arch of young sheep for 12 weeks (n = 5 per group). Non-detoxified 0.2% GA-treated roots served as controls (n = 5). Calcium analysis was based on atomic absorption spectrophotometry; morphology was assessed using light and transmission electron microscopy. RESULTS: Detoxification alone resulted in an 83% reduction of leaflet calcification (p = 0.086), but achieved only 23% (p = 0.145) and 12% (p = 0.362) mitigation of calcification in aortic wall and sinus tissue, respectively. When combined with DA-enhanced 3% GA fixation, detoxification led to a 95% reduction in leaflet calcification (p = 0.057), followed by 79% in sinus (p = 0.003) and 79% in aortic wall tissue (p = 0.0003). Morphologically, detoxification primarily affected leaflets and the subadventitial layer of aortic wall tissue, whereas enhanced fixation seemed to affect all structures. CONCLUSION: It was shown in a circulatory sheep model that a combination of DA-enhanced fixation with an extraction process of excess GA leads to a distinct mitigation of leaflet and aortic wall calcification.
