INTRA-ARTERIAL CONTRAST MATERIAL INJECTION FOR VISUALIZATION, NAVIGATION, MONITORING AND ASSESSMENT OF TREATMENT RESPONSE DURING PERCUTANEOUS CRYOABLATION OF HYPOVASCULAR LIVER METASTASES

Aim. To evaluate the possibilities of intra-arterial contrast material injection for visualization, navigation, monitoring and evaluation of treatment response during percutaneous cryoablation (PC) of hypovascular liver metastases under the control of flat-detector computed tomography (FDCT).

• Material and methods. In 2017 for treatment of 54 patients with unresectable colorectal liver metastases (n=45) and other hypovascular liver metastases (n=9) 86 procedures of angiographically-assisted FDCT-controlled PC were performed. During PC, various protocols of FDCT hepatic arteriography (FDCT-HA), which were combined with the use of iGuide Needle Guidance and 3D/3D Fusion technologies on the angiographic system Artis Zee Floor (Siemens, Germany), were applied.
• Results. The two methods of intra-arterial contrasting were the most useful during PC: 1) FDCT during capillary phase of infusion hepatic arteriography (FDCT-CPHIHA) – injection of 40 ml contrast material at a rate of 2 ml/second and scanning delay 22 seconds; 2) FDCT during interstitial phase of diffusion hepatic arteriography (FDCT-IPHDHA) – injection of 40 ml contrast material at a rate of 20 ml/minute and scanning delay 300 seconds. The FDCT-CPHIHA allowed detecting and performing PC of metastases with a diameter of less than 10 mm, including those that were not detected by any other diagnostic methods, such as ultrasound, MDCT and/or PET-CT. FDCT-IPHDHA immediately after the end of PC allowed to visualize not only the ablation zone, but also the ablated metastasis contained within it. This made it possible to accurately measure the ablation margin to assess the technical effectiveness of the procedure. FDCT-CPHIHA was also highly effective for early diagnosis of local tumor progression and local tumor recurrence in the liver during dynamic observation of patients.
• Conclusion. The use of intra-arterial contrasting fundamentally improves visualization, navigation, monitoring and evaluation of treatment response during PC of hypovascular liver metastases. The use of FDCT-HA allows not only to detect hypovascular liver metastases with a diameter of less than 10 mm, but also to carry out their PC with reliable control of the efficiency of the procedure according to the magnitude of the ablation margin.