Field Inhomogeneity-Based Catheter Visualization

With the growing interest in interventional MRI (Jolesz and Blumenfeld 1994), the visualization of catheters under MR control has become a field of intense research. Compared to conventional catheterization under fluoroscopy, MR-guided catheterization has several advantages and disadvantages. The two primary advantages of MR guidance are the lack of X-ray exposure for the patient and medical staff and the good soft tissue contrast, which allows excellent depiction of the anatomy. Unfortunately, excellent anatomic contrast is also a disadvantage during catheterization since the contrast between the background and catheter is very low compared to conventional X-ray fluoroscopy. An additional disadvantage is that MRI has lower spatial and temporal resolution. In this chapter, a new method for visualizing catheters via MRI using locally induced, interactively adaptable field inhomogeneities is presented.