Fusion in urology, "Beyond the Abstract," by Hayet Amalou, MD

BERKELEY, CA (UroToday.com) - We learn at an early age how to navigate on maps digitally. These skills are now becoming more relevant in fields of medicine like endourology, urologic surgery, and interventional radiology, that are rapidly adopting new technologies for navigating needles towards kidney and prostate tumors with hand-eye coordination and imaging feedback not dissimilar to a video game.

The gold standard that was once a total nephrectomy has evolved into a minimally- invasive outpatient nephron-sparing ablative procedure, that is guided with imaging. This guidance has also evolved from direct visualization alone with ultrasound, CT, or MRI, to a futuristic navigation platform guided by precise image fusion, where the physician can navigate needles with fusion, using images that were acquired days or even months before. The pre-operative images are fused to the procedural or intra-operative images. In this fashion, a biopsy needle (or thermal ablation probe, needle, electrode or laser fiber) device becomes an exquisite tool for both diagnostics and therapy, closing the gap between these two. This image fusion is enabled by “smart needles” and “smart ultrasound” that is equipped with electromagnetic sensors that report their location in relation to the pre-operative fusion images, a “medical GPS” for the needle.

In the last several years, image fusion has evolved from a way to co-display PET-CT images into an exquisite tool with which to apply urology and interventional radiology (IR) imaging information, where accuracy may improve outcomes. Fusion may help identify tumor at risk for under-treatment, under-heating, or under-dosing, while the patient is still on the IR table. Treatment plans based upon multimodality, multi-parametric feedback enable the use of the diagnostic imaging information during the procedure, rather than waiting for the diagnostic radiologist to issue a report months later about a PET-hot residual tumor that may have been missed during an ablation. The renal cell carcinoma seen only on arterial phase can be localized accurately with Cartesian coordinates, rather than with using landmarks or guesswork that has been inherent to urology and IR practice in the pre-fusion era. Once localized, it can be more accurately diagnosed or treated.

The gap between diagnostic imaging and therapeutic use of that information is being closed by fusion technologies. Information is power, and fusion lets the MD decide when and where the fused imaging information is needed. Rapid blending between PET, MR, CT, or US is done during the biopsy or ablation procedure, along with segmentation and real-time comparison of segmented tumor to pre-procedural imaging to planned treatment volumes, which is then compared to actual devascularized or ablated zones to assess margin and completion of treatment. This real-time feedback is available to the physician, during the procedure.

Fusion is here to stay and will continue to improve in terms of ease of use and seamless integration with workflow. Multi-parametric fusion can be useful in planning, implementing, and verifying a thermal or cryo-ablation while the patient is still on the table. Electromagnetic tracking tools are proliferating in industry, with more than 10 companies in the field. Fusion may reduce procedure time, radiation dose, and complications leading to improved outcomes. Imaging and technology come together in fusion to improve biopsy and ablation of kidney and prostate tumors. Fusion biopsy improves the prostate cancer detection rate.

This work supported by NIH Intramural Research Program & the NIH Center for Interventional Oncology. NIH does not endorse or recommend any commercial products, processes, or services. The views and opinions expressed herein do not necessarily state or reflect those of the U.S. Government.

Written by:
Hayet Amalou, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Research Fellow
Center for Interventional Oncology
Radiology & Imaging Sciences
National Institutes of Health
MSC 1182
Bethesda, MD 20892 USA

Multimodality fusion with MRI, CT, and ultrasound contrast for ablation of renal cell carcinoma - Abstract

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