Cardiovascular catheters and accessories: Ex vivo testing of ferromagnetism, heating, and artifacts associated with MRI

Abstract

The purpose of this study was to evaluate the MR safety of cardiovascular catheters and accessories. Intravascular cardiovascular catheters and accessories were tested for MR safety at 1.5 T using previously described techniques with respect to the evaluation of magnetic field attraction (deflection angle method), heating (temperature measured immediately before and after performing MRI), and artifacts (using a fast spoiled gradient-recalled acquisition in steady state [GRASS] pulse sequence). Two devices were attracted (RV pacing lead and Oximetrix 3 SO2 optical module) by the static magnetic field. Each of the other objects displayed no attraction. Heating was +0.2 degrees C for the sample cardiovascular catheter tested (Opticath). Artifacts varied from moderate to severe, depending on the amount and type of metal present in the device. Despite these ex vivo test results, further safety consideration should be given to the cardiovascular devices that have a conductive wire component (ie, certain types of the cardiovascular catheters) because of the potential for inducing current and excessive heating in these devices during MRI, especially using a high-field-strength MR system. The cardiovascular catheters evaluated in this study or those with a similar design are not recommended for use in patients undergoing MRI procedures.

Quantification of Force and Torque Applied by a High-Field Magnetic Resonance Imaging System on an Ultrasonic Motor for MRI-Guided Robot-Assisted Interventions

“…Polar graph paper was used to evaluate the deflection angle instead of the previously proposed wooden protractor [21]. The polar graph was in concentric form at a distance of 3 mm and a radial distance of 5°.…”

“…The total height from the suspension node to the tip of marker was 27 cm. The plate and colored dough weighed 30 g. The motor system, including the motor itself, encoder, and part of the shielding, weighed 195 g. The plate, threads and marker weighed 5 g. Polar graph paper was used to evaluate the deflection angle instead of the previously proposed wooden protractor [21]. The polar graph was in concentric form at a distance of 3 mm and a radial distance of 5 • .…”

“…This apparatus is advantageous compared with the proposed methods in [11,21]. The bulky motor (compared with the small volumes of implants or projectiles) can be placed on the spacious plate.…”

Safety of Magnetic Resonance Imaging in Patients With Cardiovascular Devices

“…3,78,79 The MR examination may induce sufficient voltages and currents in electrically conductive material so as to result in thermal injuries and burns to adjacent tissue (including myocardial tissue). 80,81 Although the theoretical risk exists that MR examination in patients with retained temporary epicardial leads, which consist of electrically conductive material, could lead to cardiac excitation or thermal injury, such retained leads are typically relatively short in length, usually do not form large loops, and are generally not believed to pose a significant risk during MR scanning.…”

Measuring the Temperature Increase of an Ultrasonic Motor in a 3-Tesla Magnetic Resonance Imaging System

“…After an incident where a cardiovascular catheter melted during the monitoring of a patient in a magnetic resonance imaging (MRI) system [1], there have been serious concerns pertaining to the use of surgical tools during MRI scanning. More than 70% of MRI injuries have been due to thermal burns [2].…”