Three-Dimensional Registration of Images Obtained Before and After Radiofrequency Ablation of Hepatocellular Carcinoma to Assess Treatment Adequacy

Abstract

Three-dimensional registration of pre- and postablation CT or MRI more accurately assesses the ablative margin than the conventional method. It can predict a proclivity for local recurrence after RFA according to margin grade. It also indicated that residuals and sites of no margin proximate to blood vessels that are more than 3 mm in diameter are high-risk locations for local recurrence after ablation.

Three-Dimensional Measurement of Hepatocellular Carcinoma Ablation Zones and Margins for Predicting Local Tumor Progression

“…The likelihood of local progression increases with tumor size as a result of satellite nodules (8), which is why a 5-mm minimum ablation margin is recommended by several studies (9,10). However, some of these studies (9,11,12) used a rigid registration that is not optimal for the liver because of significant deformations by respiratory movements and the ablation zone (13). Moreover, these studies assessed only two-dimensional minimal margins, failing to take into account the heterogeneous shape of the ablative volume around the tumor and that the minimal margin is not necessarily indicative of the margin sizes all around the tumor.…”

Feasibility of Extracted-Overlay Fusion Imaging for Intraoperative Treatment Evaluation of Radiofrequency Ablation for Hepatocellular Carcinoma

“…The effectiveness of RFA treatment has conventionally been assessed by side-by-side comparison of pre-and post-RFA CT images [8][9][10][11][12][13][14]20]. However, because this side-by-side interpretation tends to be inaccurate, several new methods have been developed for more accurate treatment evaluation, such as nonenhanced MR imaging [21], superparamagnetic iron oxide-MR imaging [22,23], Gd-EOB-DTPA-MR imaging [24], and iodized oil retention [25].…”

“…However, because this side-by-side interpretation tends to be inaccurate, several new methods have been developed for more accurate treatment evaluation, such as nonenhanced MR imaging [21], superparamagnetic iron oxide-MR imaging [22,23], Gd-EOB-DTPA-MR imaging [24], and iodized oil retention [25]. CT-CT/MR-MR fusion imaging was recently developed and is considered to be a useful imaging modality for RFA evaluation in terms of its accuracy, quantitative nature, noninvasiveness, and applicability to hypovascular lesions [8][9][10][11][12][13][14]. In the present study, we analyzed the clinical Group I: margin <0 mm (tumor extends outside the ablation zone); group II: margin 0 to <5 mm; group III: margin ≥5 mm.…”

“…Computed tomography/magnetic resonance-ultrasonography (CT/MR-US) fusion imaging, which enables the synchronous display of real-time US images and cross-sectional multiplanar reconstruction CT or MR images, is reportedly useful for RFA treatment guidance [1][2][3][4][5][6][7]. Moreover, although pre-and post-RFA CT or MR images have been conventionally compared side-byside to evaluate therapeutic responses, pre-and post-RFA CT-CT/MR-MR fusion images have made it possible to more accurately measure minimal ablative margins [8][9][10][11][12][13][14].…”

Radiology in Transplant

“…Sakakibara et al [13] previously used side-by-side comparisons of preand post-RFA imaging studies in 139 HCC nodules in 84 patients, and retrospectively performed 3D registration on the imaging from the same studies. They found that histological grade at the margin and proximity to blood vessels ≥3 mm were predictors of tumor recurrence.…”