Ferenc A. Jolesz

24 – Advanced Nonrigid Registration Algorithms for Image Fusion

This chapter presents an original method to perform nonrigid registration of multimodal images. This iterative algorithm is composed of two steps: the intensity transformation and the geometrical transformation. Two intensity transformation models are proposed, which assume either monofunctional or bifunctional dependence between the intensity values in the images being matched. Both of these models are built using robust estimators to enable precise and accurate transformation solutions. The chapter describes the image registration strategy applied prospectively during several neurosurgical cases. The enhancement provided by intraoperative nonrigid registration to the surgical visualization environment is shown by matching the corticospinal tract of a preoperatively prepared anatomical atlas to the initial and subsequent intraoperative scans of a subject. This matching was carried out prospectively during the neurosurgery, demonstrating the practical value of the approach and its ability to meet the real-time constraints of surgery. The entire image analysis process can be completed in less than 10 min, which has been adequate to display the information to the surgeon.

Magnetic Resonance Imaging-Guided Interstitial Prostate Brachytherapy

Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States and the second leading cause of cancer mortality (1). The natural history of treated clinically localized and potentially curable disease is often protracted. As a result, side effects sustained from the primary treatment may persist for extended periods, often several decades. Therefore, it is important that the treatment, whose goal is to permanently eradicate the disease, also have acceptable complication rates, leaving the patient with an acceptable quality of life after therapy is complete. To this end, efforts aimed at providing a minimally invasive alternative to radical prostatectomy (RP) for the curative treatment of patients with clinically localized prostate cancer have been made.