Magnetic resonance conditionality of abandoned leads from active implantable medical devices at 1.5 T

Abstract

During MR scans, abandoned leads from active implantable medical devices (AIMDs) can experience excessive heating at the lead tip, depending on the type of termination applied to the proximal contacts (proximal end treatment). The influence of different proximal end treatments (ie, [1] freely exposed in the tissue, [2] terminated with metal in contact with the tissue, or [3] capped with plastic, and thereby fully insulated, on the RF-induced lead-tip heating) are studied. A technique to ensure that MR Conditional AIMD leads remain MR Conditional even when abandoned is recommended. Methods: Abandoned leads from three MR Conditional AIMDs ([1] a sacral neuromodulation system, [2] a cardiac rhythm management pacemaker system, and [3]a deep brain stimulator system) were investigated in this study. The computational lead models (ie, the transfer functions) for different proximal end treatments were measured and used to assess the in vivo lead-tip heating for four virtual human models (FATS, Duke, Ella, and Billie) and compared with the lead-tip heating of the complete MR Conditional AIMD system. Result: The average and maximum lead-tip heating for abandoned leads proximally capped with metal is always lower than that from the complete AIMD system. Abandoned leads proximally insulated could lead to an average in vivo temperature rise up to 3.5 times higher than that from the complete AIMD system. Conclusion: For the three investigated AIMDs under 1.5T MR scanning, our results indicate that RF-induced lead-tip heating of abandoned leads strongly depends on the proximal lead termination. A metallic cap applied to the proximal termination of the tested leads could significantly reduce the RF-induced lead-tip heating.

Age and lead configuration matter: A comparative study of RF-induced heating of epicardial and endocardial electronic devices in adult and pediatric anthropomorphic phantoms in 1.5 T MR

“…Since MR-Conditional labeling of a CIED only applies to the intact device with leads implanted in their original configuration, patients with abandoned leads are contraindicated for MRI. A recent study showed that capped abandoned leads induce tissue heating that is on average 3.5 times higher than what is generated by a complete CIED system (40). Thus, results of this study should not be generalized to cases of abandoned leads.…”

RF‐induced heating for active implantable medical devices in dual parallel leads configurations at 1.5 T MRI

“…There are 49 landmarks for each human body model using a 25‐mm step size to cover the imaging of the head region down to the foot/ankle region. Two different generic RF coils are used in the simulations 17 . The larger coil used for adult obese male simulations has a length of 650 mm, a diameter of 700 mm, and 16 rungs.…”

“…Consequently, in ISO/TS 10974, a more efficient transfer function (TF) method is proposed and utilized to assess the RF‐induced heating for AIMD systems. Combined with clinically relevant incident electric fields along possible implantation pathways inside human body models or inside the American Society for Testing and Materials (ASTM) phantom, the TF method can quickly numerically predict the RF‐induced heating for both inside human body models and in vitro scenarios 17–20 …”

Joint British Society consensus recommendations for magnetic resonance imaging for patients with cardiac implantable electronic devices

“…Experimental evidence to help quantify the risks of abandoned or fractured transvenous permanent pacemaker and defibrillator leads is mixed with some studies suggesting large temperature increases both in vitro56 57 and in vivo animal studies 58. More recently, in vitro testing at 1.5 T has demonstrated greater MRI-induced heating in abandoned leads (up to 29.9°C) compared with pacemaker-connected leads (up to 11.6°C),59 60 although temperature rises were strongly dependent on lead length and were generally higher when the abandoned leads were capped.…”