Method for Target Tracking in Focused Ultrasound Surgery of Liver using Magnetic Resonance Filtered Venography

• Published in: 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society Vol. 2007; pp. 2614 - 2617
• Main Authors: Kokuryo, D., Kaihara, T., Kumamoto, E., Fujii, S., Kuroda, K.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 01.01.2007
• Subjects: Abdomen; Biomechanical Phenomena; Focusing; Humans; Liver; Liver - diagnostic imaging; Liver - surgery; Magnetic resonance; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Magnetic separation; Phlebography - instrumentation; Phlebography - methods; Respiration; Rotation measurement; Surgery; Target tracking; Ultrasonic imaging; Ultrasonography; Veins
• ISBN: 9781424407873; 1424407877
• ISSN: 1094-687X; 1557-170X; 1558-4615
• DOI: 10.1109/IEMBS.2007.4352865

The purpose of this work is to develop a magnetic resonance (MR) technique for guiding a focal point created in focused ultrasound surgery (FUS) onto a specific target position in an abdominal organ, such as the liver, which moves and deforms with respiratory motion. The translational distance, rotational angles, and amount of expansion and contraction of the organ tissue were measured by obtaining the gravity points of the veins filtered from the sagittal, cine MR images of healthy livers during free breathing. Using the locations of the vessels at each time point, the target position at which the ultrasound focus was to be placed was estimated. In the volunteer experiments (N = 2), the lower limit of the spatial matrix dimension for delineating the veins was 128 x 128. The average displacement of the liver was 19.6 + 3.6 mm in superior-inferior (SI) direction and 3.1 + 1.4 mm in anterior-posterior (AP) direction. The deformations were 3.7 + 1.1 mm in SI direction and 3.0 + 1.2 mm in AP direction. The error between the actual and the estimated target point was 0.7 plusmn 0.5 mm in SI direction, 0.6 plusmn 0.4 mm in AP direction and 1.0 plusmn 0.5 mm in distance, and less than 2.1 mm in all the trials. These results suggested that the proposed technique is sufficient for targeting the focus on a specific tissue location and for tracking the slice slab for thermometry to cover the region of focus.