Comparative analysis of traditional and coiled fiducials implanted during EUS for pancreatic cancer patients receiving stereotactic body radiation therapy

Abstract

Background: EUS-guided fiducial placement facilitates image-guided radiation therapy (IGRT).

Objective: To compare 2 types of commercially available fiducials for technical success, complications, visibility, and migration.

Design: Retrospective, single-center, comparative study.

Setting: Tertiary-care medical center.

Interventions: Traditional fiducials (TFs) (5-mm length, 0.8-mm diameter) and Visicoil fiducials (VFs) (10-mm length, 0.35-mm diameter) were compared. Fiducials were placed using linear 19-gauge (for TFs) or 22-gauge (for VFs) needles. A subjective visualization scoring system (0-2; 0 = not visible, 1 = barely visible, 2 = clearly visible) was used to assess visibility on CT. Fiducial migration was calculated as a change in interfiducial distance.

Main outcome measurements: Technical success, complications, visibility, and migration of 2 types of fiducials.

Results: Thirty-nine patients with locally advanced pancreatic cancer underwent EUS-guided placement of 103 fiducials (77 TFs, 26 VFs). The mean number of fiducials placed per patient was 2.66 (standard deviation 0.67) for the 19-gauge needle and 2.60 (standard deviation 0.70) for the 22-gauge needle (P = .83). No intra- or postprocedural complications were encountered. The median visibility score for TFs was significantly better than that for VFs, both when scores of 0 were and were not included (2.00, interquartile range [IQR] 2.00-2.00 vs 1.75, IQR 1.50-2.00, P = .009 and 2.00, IQR 2.00-2.00 vs 2.00, IQR 1.50-2.00, P < .0001, respectively). The mean migration was not significantly different between the 2 types of fiducials (0.8 mm [IQR 0.4-1.6 mm] for TFs vs 1.3 mm [IQR 0.6-1.5 mm] for VFs; P = .72).

Limitations: Retrospective, nonrandomized design.

Conclusions: Visibility was significantly better for TFs compared with VFs. The degree of fiducial migration was not significantly different for TFs and VFs. There was no significant difference in the mean number of fiducials placed, indicating a similar degree of technical difficulty for TF and VF deployment.

Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Figures

Figure 1

A, EUS image of a mass in the head of the pancreas. EUS-guided FNA confirmed pancreatic ductal adenocarcinoma. B, EUS image showing FNA needle and a deployed hyperechoic fiducial (arrow).

Figure 2

Examples of visibility scores (0, 1, and 2) on the primary treatment plan and the secondary treatment plan of the same patient (and example of blurriness of conebeam CT (CBCT) compared with treatment plan, as mentioned in the discussion section). A, Primary treatment plan (free breathing) showing 3 fiducials that were scored as a visibility score of 2 (patient also had a biliary stent in place). B, Secondary CBCT treatment plan showing 1 fiducial (visualization score of 1) and 2 fiducials with a score of 0. (The biliary stent is still clearly visible. This is the best contrast given the artifact from stent.)

Figure 3

Example of an unmarked breath-held CT treatment plan; 3 views (axial, sagittal, coronal); isocenter of pancreas tumor shown at target and 2 fiducials (arrow).

Figure 4

Previously shown treatment plan with fiducials contoured and centroid (arrow) automatically placed on Pinnacle; 3 views (axial, sagittal, coronal).