A next-generation, flow-diverting implant used to treat brain aneurysms: in vitro evaluation of magnetic field interactions, heating and artifacts at 3-T.
OBJECTIVE
Fine-mesh braided, stent-like structures (flow diverters) have been proposed for treatment of brain aneurysms. To date, the safety of performing magnetic resonance imaging (MRI) in patients with these implants is unknown. Therefore, the purpose of this study was to evaluate MRI issues at 3-T for a new flow-diverting implant used to treat brain aneurysms.


METHODS
The Surpass NeuroEndoGraft (Surpass Medical, Ltd., Tel Aviv, Israel) underwent evaluation for magnetic field interactions, MRI-related heating and artifacts using standardized techniques. Magnetic field interactions were assessed for this implant with regard to translational attraction (i.e., using the deflection angle technique) and torque (qualitative assessment method). MRI-related heating was evaluated by placing the implant in a gelled-saline-filled, head/torso phantom and performing MRI using a transmit/receive radiofrequency body coil at a whole-body-averaged specific absorption rate of 2.9 W/kg for 15 min. Artifacts were characterized using T1-weighted, spin echo (SE) and gradient echo (GRE) pulse sequences.


RESULTS
The Surpass NeuroEndoGraft exhibited minor magnetic field interactions (21° deflection angle and no torque), which were acceptable from a safety consideration. Heating was not substantial, with the highest temperature change being 2.3°C (background temperature rise without the implant was 1.5°C). Artifacts may create issues if the area of interest is in the same area or close to this implant.


CONCLUSIONS
The findings demonstrated that it would be acceptable for patients with this next-generation, flow-diverting implant to undergo MRI at 3-T or less.
Loyola Marymount University, Los Angeles, CA 90045, USA. akaracoz@lion.lmu.edu
Alexandra M
AM
Karacozoff
Frank G
FG
Shellock
Ajay K
AK
Wakhloo
D016477:Artifacts; D001807:Blood Vessel Prosthesis; D001831:Body Temperature / Q000528:radiation effects; D019544:Equipment Failure Analysis; D006801:Humans; D066298:In Vitro Techniques; D002532:Intracranial Aneurysm / Q000503:physiopathology* / Q000601:surgery*; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D011474:Prosthesis Design; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D016896:Treatment Outcome