Percutaneous Angiographically Assisted Cryoablation of Renal Cell Carcinoma under the Control of Flat-Detector Computed Tomography: Capabilities and Potential Advantages of the Technique

Purpose: Percutaneous cryoablation (PCA) of renal cell carcinoma (RCC) stage T1a (≤4 cm) generally performed using MDCT with intravenous contrast material administration. Most interventional radiology departments are not equipped MDCT scanners and this is holding back widespread adoption of this technique into practical medicine. Flat-detector computed tomography (FDCT) is included in the standard equipment of modern angiographic systems, which makes it possible to combine the technologies of computed tomography with various technologies of intra-arterial contrasting and endovascular treatment. The purpose of the study was to assess the possibilities and potential advantages of using intraarterial contrasting during FDCT-controlled PCA of RCC T1a.Material and methods: Since 2017 angiographically assisted PCA under the FDCT control performed in 14 patients with RCC T1a. The procedure was performed in the X-ray operating room on an Artis Zee Floor angiographic unit with FDCT function and iGuide Needle Guidance and 3D/3D Fusion technologies (Siemens, Germany) using the SeedNet Gold system and IceEDGE 13 G, IceRod 17 G or IceSphere 17 G cryoprobes (Galil Medical, USA). At all stages of the procedure, FDCT-arteriography of the kidney (FDCT-A) performed according to the original technique: injection into the renal artery 12 ml of non-ionic contrast materials at a rate of 1 ml/s and performing scanning 5 s after the start of contrast materials injection.Results: The primary technical efficiency of FDCT-controlled PCA of RCC T1a was 92.9 %, the secondary — 100 %. Complications of grade 3 according to the CIRSE classification were identified in three patients (21.4 %), complications of grade 4, 5 and 6 not observed. The use of arterial access and the FDCT-A execution at different stages of PCA had the following advantages: 1) high-quality visualization of the tumor with minimal consumption of contrast materials; 2) simple and accurate positioning of cryoprobes using the iGuide Needle Guidance program; 3) estimation of the future ablative margin by fusion FDCT data about tumor with FDCT data about ice ball; 4) reliable diagnosis of bleeding after removal of cryoprobes with the possibility of immediate performing of endovascular hemostasis.Conclusion: Percutaneous angiographically assisted cryoablation under the FDCT control is an affordable, safe and effective technology for the treatment of RCC T1a, which has a number of potential advantages compared to performing procedures using MDCT control. Further research is advisable to study of this PCA technique with its subsequent possible introduction into the routine practice in Interventional Radiology departments of multidisciplinary oncological hospitals.

How to iGuide: flat panel detector, CT-assisted, minimally invasive evacuation of intracranial hematomas

Evidence is growing to support minimally invasive surgical evacuation of intraparenchymal hematomas, particularly those with minimal residual hematoma volumes following evacuation. To maximize the potential for neurologic recovery, it is imperative that the trajectory for access to the hematoma minimizes disruption of normal parenchyma. Flat panel detector CT-based navigation and needle guidance software provides a platform that uses flat panel detector CT imaging obtained on the angiography table to aid reliable and safe access to the hematoma. In addition to providing a high degree of accuracy, this method also allows convenient and rapid re-imaging to assess navigation accuracy and the degree of hematoma evacuation prior to procedural completion. We provide a practical review of the syngo iGuide needle guidance software and the methodology for incorporating its use, and the software of other vendors, in a variety of minimally invasive methods for evacuation of intraparenchymal hematomas.

Annular Fiber Probe for Interstitial Illumination in Photoacoustic Guidance of Radiofrequency Ablation

Unresectable liver tumors are commonly treated with percutaneous radiofrequency ablation (RFA). However, this technique is associated with high recurrence rates due to incomplete tumor ablation. Accurate image guidance of the RFA procedure contributes to successful ablation, but currently used imaging modalities have shortcomings in device guidance and treatment monitoring. We explore the potential of using photoacoustic (PA) imaging combined with conventional ultrasound (US) imaging for real-time RFA guidance. To overcome the low penetration depth of light in tissue, we have developed an annular fiber probe (AFP), which can be inserted into tissue enabling interstitial illumination of tissue. The AFP is a cannula with 72 optical fibers that allows an RFA device to slide through its lumen, thereby enabling PA imaging for RFA device guidance and ablation monitoring. We show that the PA signal from interstitial illumination is not affected by absorber-to-surface depth compared to extracorporeal illumination. We also demonstrate successful imaging of the RFA electrodes, a blood vessel mimic, a tumor-mimicking phantom, and ablated liver tissue boundaries in ex vivo chicken and bovine liver samples. PA-assisted needle guidance revealed clear needle tip visualization, a notable improvement to current US needle guidance. Our probe shows potential for RFA device guidance and ablation detection, which potentially aids in real-time monitoring.