Utility of computed tomography fusion imaging for the evaluation of the ablative margin of radiofrequency ablation for hepatocellular carcinoma and the correlation to local tumor progression.

Aim: To demonstrate the usefulness of the computed tomography (CT) fusion imaging for the evaluation of treatment effect of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

Methods: Eighty-five patients with 94 HCC with complete ablation judged on conventional side-by-side interpretation of pre-RFA and post-RFA CT at the time of RFA were included in this retrospective study. CT data was retrospectively used to create fusion images of pre-RFA and post-RFA CT using automatic rigid registration and manual correction referring to intrahepatic structures and hepatic contours around a tumor.

[Characteristic of the image by image reconstruction method applied to successive approximation method].

In recent years, an applied successive approximation method has emerged as a new reconstruction technique of the computed tomography (CT). The CT unit of our hospital is equipped with an adaptive statistical iterative reconstruction (ASiR) which applies this method. This time, we have investigated the feature of the images through the ASiR.

[Method of measuring modulation transfer function in computed tomography using slit method with air gap phantom].

There are several methods for measuring modulation transfer function (MTF) in computed tomography (CT) images. The aluminum slit method, scanning a phantom consisting of a thin aluminum foil sandwiched by flat plastic slabs, is a standard method for measuring field of view (FOV) in clinical CT scan. But this method requires extreme caution when handling metal foil of high precision.