Application of Subtraction Iodine Mapping in the Immediate Liver Tumour Ablation CT Scan – Initial Experience Report

Purpose

To share our initial experience and benefits of the iodine mapping application in the post-liver radiofrequency ablation CT scan compared to conventional post-contrast CT liver image reconstruction.

Methodology

The SGH hybrid angiography-CT System (installed 2021), comprises the Genesis edition CT system and Alphenix Sky+ angiography system. The CT scanner gives 640 slices per rotation, with a maximum of 16cm field coverage. Iodine mapping in the post-liver ablation is routinely performed on the post-ablation contrast-enhanced CT. This subtraction technique involves taking two scan volumes and subtracting the images to highlight the differential contrast uptake in the liver parenchyma. Color-coded maps of iodine distribution within the liver parenchyma are then generated to demonstrate enhancement and washout to facilitate interpretation.

We plan to showcase the application of the iodine map technique in liver tumor ablation to through a small retrospective case series.

Result

Through a series of 5 cases, we plan to demonstrate how iodine mapping from subtraction CT imaging after liver tumor ablation facilitates the detection of any non-ablated residual tumors and bleeding which is the most dreaded acute complication. In particular, how it is an improvement from conventional post-contrast CT image reconstructions. In addition, we will show pitfalls in imaging to prevent misinterpretation of iodine mapping subtraction CT.

Summary

Our initial experience in the application of iodine mapping for immediate post-liver ablation scans demonstrates that it is a useful adjunct for the interpretation of post-liver ablation CT to provide more early and accurate detection of residual tumors and complications.