Three-dimensional spatial and temporal temperature control with MR thermometry-guided focused ultrasound (MRgHIFU).
High-intensity focused ultrasound (HIFU) is an efficient noninvasive technique for local heating. Using MRI thermal maps, a proportional, integral, and derivative (PID) automatic temperature control was previously applied at the focal point, or at several points within a plane perpendicular to the beam axis using a multispiral focal point trajectory. This study presents a flexible and rapid method to extend the spatial PID temperature control to three dimensions during each MR dynamic. The temperature in the complete volume is regulated by taking into account the overlap effect of nearby sonication points, which tends to enlarge the heated area along the beam axis. Volumetric temperature control in vitro in gel and in vivo in rabbit leg muscle was shown to provide temperature control with a precision close to that of the temperature MRI measurements. The proposed temperature control ensures heating throughout the volume of interest of up to 1 ml composed of 287 voxels with 95% of the energy deposited within its boundaries and reducing the typical average temperature overshoot to 1 degrees C.
Mougenot
Charles
C
Laboratory for Molecular and Functional Imaging: From Physiology to Therapy, UMR5231 Centre National de la Recherche Scientifique/Université Victor Segalen Bordeaux 2, Bordeaux, France.
Quesson
Bruno
B
de Senneville
Baudouin Denis
BD
de Oliveira
Philippe Lourenco
PL
Sprinkhuizen
Sara
S
Palussière
Jean
J
Grenier
Nicolas
N
Moonen
Chrit T W
CT
D000465:Algorithms; D000818:Animals; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D018482:Muscle, Skeletal / Q000473:pathology* / Q000528:radiation effects; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013813:Therapy, Computer-Assisted / Q000379:methods*; D013817:Thermography / Q000379:methods*; D014464:Ultrasonic Therapy / Q000379:methods*