Development of an intravascular heating source using an MR imaging guidewire.
OBJECTIVE
To develop a novel endovascular heating source using a magnetic resonance (MR) imaging guidewire (MRIG) to deliver controlled microwave energy into the target vessel for thermal enhancement of vascular gene transfection.


METHODS
A 0.032-inch MRIG was connected to a 2.45-GHz microwave generator. We 1) calculated the microwave power loss along the MRIG, 2) simulated the power distribution around the MRIG, 3) measured the temperature increase vs. input power with the MRIG, and 4) evaluated the thermal effect on the balloon-compressed/microwave-heated aorta of six living rabbits. In addition, during balloon inflation, we also simultaneously generated high-resolution MR images of the aortic wall.


RESULTS
The power loss was calculated to be 3.9 dB along the MRIG. The simulation-predicted power distribution pattern was cylindrically symmetric, analogous to the geometry of vessels. Under balloon compression, the vessel wall could be locally heated at 41 degrees C with no thermal damage apparent on histology.


CONCLUSIONS
This study demonstrates the possibility of using the MRIG as a multifunctional device, not only as a receiver antenna to generate intravascular high-resolution MR images of atherosclerotic plaques and as a conventional guidewire to guide endovascular interventions during MR imaging, but also as a potential intravascular heating source to produce local heat for thermal enhancement of vascular gene transfection.
Qiu
Bensheng
B
Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, USA.
Yeung
Christopher J
CJ
Du
Xiangying
X
Atalar
Ergin
E
Yang
Xiaoming
X
D000818:Animals; D001011:Aorta / Q000033:anatomy & histology; D001161:Arteriosclerosis / Q000175:diagnosis; D004867:Equipment Design; D018014:Gene Transfer Techniques / Q000295:instrumentation; D006358:Hot Temperature; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008872:Microwaves; D011817:Rabbits