Table 1 A comparison of catheter designs for interventional MRI.
From: Interventional cardiovascular magnetic resonance: still tantalizing
Approach | Advantages | Disadvantages | Examples |
|---|---|---|---|
Passive catheters, visible based on intrinsic materials properties | Simple, inexpensive Can be used in combination with other approaches | Non-specific catheter "signatures" "Compatible" conductive wires can heat Must not contain ferrous braids | Gadolinium-filled balloon dilatation catheters. Non-braided angiography catheters Polymer guidewires [57] |
Active "imaging" catheters, incorporating MRI antennae | Highly conspicuous Catheters can be depicted in color Versatile imaging approaches including projection-mode | Complex, expensive Conductive wires can heat Blurry profile compared with X-ray catheters Dipole designs have poor distal tip visibility | Surgi-Vision Intercept 0.030" dipole guidewire coil Boston Scientific MRI Stilletto endomyocardial injection system |
Active "tracking" catheters, incorporating MRI antennae | Simple, inexpensive Coils can be tracked without imaging, to increase speed, reduce heating, reduce acoustic noise Coils can be used to automate scan plane adjustments | No real-time MRI Catheter locations are computer-synthesized on image Conductive wires can heat | MGH/General Electric electroanatomic mapping and MRI system [36] |
Active catheters inducing susceptibility artifacts | Simple Controlled artifacts confer specificity | No imaging Heating of transmission lines when employed | Fiberoptic-detuned tracking coil [72] |
Inductively-coupled devices | Requires no physical connection Reverse polarization mode may display unique device signature and allow high flip angle | Embeds electronics that might interfere with mechanical performance (i.e. on stents) Low flip angle compromises imaging | |
Multispectral devices | Non-proton MRI species can be displayed in different colors from target tissue Passive imaging that does not require transmission lines or embedded electronics | Additional hardware required for exciting and detecting the alternate compounds Hyperpolarized 13C requires constant replenishment using specialized generator hardware | 13C selective coronary arteriography [78] 19F catheter tracking [76] |
Magnetically-deflected devices | Harness magnetic field to steer or even un-tether device | May compromise imaging May compromise mechanical capabilities | Untethered device navigation [75] |
Integrated catheter MRI | Requires no conventional MRI Operates inside ordinary X-ray lab | Non-imaging device | Topspin intracoronary catheter [80]. |