Thermal effect of intravascular MR imaging using an MR imaging-guidewire: an in vivo laboratory and histopathological evaluation.
BACKGROUND
Intravascular magnetic resonance (MR) imaging to guide interventional procedures is a rapidly growing field. A primary concern with these new techniques is their thermal safety. The purpose of this study was to evaluate, in vivo, the thermal effect of an MR imaging-guidewire (MRIG) for intravascular MR imaging (IVMRI).


METHODS
Two indications of potentially adverse local heating were investigated: blood coagulation disorders and pathologic changes in target vessels. Experiments were performed on ten rabbits with a 1.5 T MR scanner. Using a 0.64-mm MRIG as the RF receiver, we imaged the target aorta using a fast spin-echo pulse sequence with an average specific absorption rate (SAR) of 0.6 W/kg. The total MR imaging time was approximately 70 minutes.


RESULTS
There were no abnormal value changes of the coagulation factors between pre- and post-IVMRI, no clinical manifestations of blood coagulation disorders, and, histopathologically, no thermal damage in target vessels.


CONCLUSIONS
This study demonstrates, from a pathophysiological point of view, the potential safe use of the MR imaging-guidewire for intravascular MR imaging. Further study is required to precisely define the boundaries of these safe operating parameters.
Yang
Xiaoming
X
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-0845, USA. xyang@mri.jhu.edu
Yeung
Christopher J
CJ
Ji
Hongxiu
H
Serfaty
Jean-Michel
JM
Atalar
Ergin
E
D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology*; D001778:Blood Coagulation Disorders / Q000378:metabolism / Q000473:pathology; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000379:methods; D011817:Rabbits; D011846:Radio Waves / Q000009:adverse effects; D025321:Surgery, Computer-Assisted / Q000379:methods*