Browsing by Subject "Real-time imaging"

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    Magnetic resonance imaging–guided coronary interventions
    (John Wiley & Sons, 2004) Tsekos, N. V.; Ergin, A.; Li, D.; Omary, R. A.; Serfaty, J.-M.; Woodard, P. K.
    Magnetic resonance imaging (MRI) guidance for coronary interventions offers potential advantages over conventional x‐ray angiography. Advantages include the use of nonionizing radiation, combined assessment of anatomy and function, and three‐dimensional assessment of the coronary arteries leading to the myocardium. These advantages have prompted a series of recent studies in this field. Real‐time coronary MR angiography, with low‐dose catheter‐directed intraarterial (IA) infusion of contrast media, has achieved in‐plane spatial resolution as low as 0.8 × 0.8 mm2 and temporal resolution as short as 130 msec per image. Catheter‐based IA injection of contrast agent has proven useful in the collection of multislice and three‐dimensional images, not only for coronary intervention guidance, but also in the assessment of regional myocardial perfusion fed by the affected vessel. Actively visible guidewires and guiding catheters, based on the loopless antenna concept, have been effectively used to negotiate tortuous coronary vessels during catheterization, permitting placement of coronary angioplasty balloon catheters. Passive tracking approaches have been used to image contrast agent–filled coronary catheters and to place susceptibility‐based endovascular stents. Although the field is in its infancy, these early results demonstrate the feasibility for performing MRI‐guided coronary interventions. Although further methodological and technical developments are required before these methods become clinically applicable, we anticipate that MRI someday will be included in the armamentarium of techniques used to diagnose and treat coronary artery disease.
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    Real-time three-dimensional image reconstruction using alternating direction method of multipliers for magnetic particle imaging
    (IEEE, 2018) İlbey, Serhat; Güngör, A.; Top, C. B.; Sarıtaş, Emine Ülkü; Güven, H. E.
    Manyetik Parçacık Görüntüleme (MPG), süperparamanyetik demiroksit nanoparçacıklarının uzamsal dağılımını tespit etmekte kullanılan görece yeni bir medikal görüntüleme yöntemidir. MPG’de görüntü geriçatımı için kullanılan yöntemlerden biri sistem matrisi yaklaşımıdır. Bu yöntemde öncelikle kalibrasyon ölçümleri yapılarak sistem matrisi elde edilir. Daha sonra, sistem matrisi ve görüntülenen objeden alınan veri ile bir doğrusal denklem sistemi oluşturulur ve görüntülenen alandaki manyetik parçacık dağılımı yinelemeli düzenlileştirme veya eniyileme algoritmaları ile çözülür. Bu çalışmada, grafik işlemciler kullanılarak yön degiştiren çarpanlar yöntemi ile üç boyutlu bir görüntüleme uzayında gerçek zamanlı görüntü geriçatımı yapılabileceği gösterilmiştir.