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Sci‐PM Thurs ‐ 05: Improving background suppression in magnetic resonance‐guided endovascular therapy
Author(s) -
Draper J,
Lauzon M,
Frayne R
Publication year - 2005
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2030975
Subject(s) - magnetic resonance imaging , catheter , medicine , imaging phantom , radiology , flip angle , scanner , nuclear medicine , biomedical engineering , computer science , artificial intelligence
Vascular disease is a leading cause of death in Canada. Endovascular therapy represents a minimally invasive means of treating this disease. The current clinical standard for endovascular treatment uses x‐ray imaging as the modality to visualize the vasculature and devices introduced into the vascular system. Magnetic resonance (MR) imaging is a better modality in terms of patient safety and has potential for use in clinical endovascular therapy. Before that can happen, we must show that we can reliably visualize and track catheters within a slice of tissue under MR guidance. One way of increasing catheter conspicuity is the projection dephaser (PD) method of background suppression.(Dixon et al., MRM, 1986 ) We propose another approach, in which multiple phase cycles are applied over the slice thickness, such that upon projection into one plane, the background tissue signal adds destructively while the catheter signal is minimally affected. In a 3 Tesla MR scanner, we imaged a 4 French catheter (1.3 mm) in a pork chop phantom with a fast spoiled gradient echo sequence (repetition time/echo time/ flip angle/ slice thickness = 7.5 ms/ 3.6 ms/ 20°/ 70 mm). Visual analysis of acquired images shows that catheter conspicuity is significantly improved over the PD method. Quantitatively, catheter contrast,C = ( S c− S b) / ( S c+ S b ) , in the PD‐suppressed image is 15% ( S c = catheter signal, S b = background signal). With 35 phase cycles over the slice thickness, C is increased to 44%. These results show that this background suppression technique has potential for use in MR‐guided endovascular procedures.