Abstract
It is extremely important to develop an effective method for the registration of ultrasound images acquired at different stages of diagnosis and treatment. Reliable image registration is very useful for monitoring tumors over time and for evaluating therapeutic effectiveness, which are essential for determining the most appropriate clinical management of the patient. Intensive research has led to considerable progress in image registration for diagnostic modalities such as CT, MR, and PET. However, due to various factors peculiar to ultrasound examinations, there have been significantly fewer research studies on image registration focusing on ultrasound than on other diagnostic modalities. Diagnostic ultrasound systems that can acquire and record three-dimensional volume data continuously have recently been developed. In ultrasound diagnosis, it is extremely important to be able to reliably match the positions of a series of images obtained at various stages of the diagnostic and therapeutic processes. This has led to strong demand for a reliable image registration technique. The use of ultrasound-guided radiofrequency ablation (RFA) in the treatment of liver cancer has now become widespread. As an application developed for RFA, the present study introduces a volume similarity index that uses two or more small regions. The results of this study demonstrate that effective image registration can be achieved for ultrasound images.
