Quantitative margin assessment of radiofrequency ablation of a solitary colorectal hepatic metastasis using MIRADA RTx on CT scans: a feasibility study

• Published in: BMC medical imaging Vol. 19; no. 1; p. 71
• Main Authors: Sibinga Mulder, B G, Hendriks, P, Baetens, T R, van Erkel, A R, van Rijswijk, C S P, van der Meer, R W, van de Velde, C J H, Vahrmeijer, A L, Mieog, J S D, Burgmans, M C
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 20-08-2019; BioMed Central; BMC
• Subjects: Ablation; Aged; Care and treatment; Co-registration; Colorectal cancer; Colorectal liver metastases; Colorectal Neoplasms - diagnostic imaging; Colorectal Neoplasms - pathology; Colorectal Neoplasms - therapy; Computed tomography; Confidentiality; Contrast Media; CT imaging; Electrodes; Feasibility Studies; Female; Humans; Liver; Liver - diagnostic imaging; Liver - pathology; Liver cancer; Liver Neoplasms - diagnostic imaging; Liver Neoplasms - pathology; Liver Neoplasms - secondary; Liver Neoplasms - therapy; Local recurrence; Male; Margins of Excision; Medical imaging; Metastases; Metastasis; Middle Aged; Patients; Radio frequency; Radiofrequency Ablation; Radiographic Image Interpretation, Computer-Assisted - methods; Registration; Reproducibility; Retrospective Studies; Software; Success; Surgery; Technical Advance; Tomography, X-Ray Computed - methods; Netherlands; Radiofrequency ablation; Co-registration; Colorectal liver metastases; Local recurrence
• ISSN: 1471-2342; 1471-2342
• DOI: 10.1186/s12880-019-0360-2

Compared to surgery, radiofrequency ablation(RFA) for colorectal liver metastasis(CRLM) is associated with higher local recurrence(LR) rates. A wide margin (at least 5 mm) is generally recommended to prevent LR, but the optimal method to assess ablation margins is yet to be established. The aim of our study was to evaluate the feasibility and reproducibility of CT-CT co-registration, using MIRADA software, in order to assess ablation margins of patients with CRLM.
In this retrospective study, pre- and post-ablation contrast-enhanced CT scans of 29 patients, treated with percutaneous RFA for a solitary CRLM, were co-registered. Co-registration was performed by two independent radiologist, based on venous structures in proximity to the tumor. Feasibility of CT-CT co-registration and inter-observer agreement for reproducibility and ablation margins was determined. Furthermore, the minimal ablation margin was compared with the occurrence of LR during follow-up.
Co-registration was considered feasible in 18 patients (61% male, 63.1(±10.9) year), with a perfect inter-observer agreement for completeness of ablation: κ = 1.0(p < 0.001). And substantial inter-observer agreement for measurement of the minimal margin (≤ 0 mm, 1-5 mm, ≥ 5 mm): κ = 0.723(p-value < 0.001). LR occurred in eight of nine(88.9%) incompletely ablated CRLM and in one of the nine completely ablated CRLM(11.1%).
Co-registration using MIRADA is reproducible and potentially a valuable tool in defining technical success. Feasibility of co-registration of pre- and post-ablation CT scans is suboptimal if scans are not acquired concordantly. Co-registration may potentially aid in the prediction of LR after percutaneous ablation.