GTV delineation in supraglottic laryngeal carcinoma: interobserver agreement of CT versus CT-MR delineationReport as inadecuate




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Radiation Oncology

, 10:26

First Online: 23 January 2015Received: 02 September 2013Accepted: 23 December 2014DOI: 10.1186-s13014-014-0321-4

Cite this article as: Jager, E.A., Kasperts, N., Caldas-Magalhaes, J. et al. Radiat Oncol 2015 10: 26. doi:10.1186-s13014-014-0321-4

Abstract

BackgroundGTV delineation is the first crucial step in radiotherapy and requires high accuracy, especially with the growing use of highly conformal and adaptive radiotherapy techniques. If GTV delineations of observers concord, they are considered to be of high accuracy.

The aim of the study is to determine the interobserver agreement for GTV delineations of supraglottic laryngeal carcinoma on CT and on CT combined with MR-images and to determine the effect of adding MR images to CT-based delineation on the delineated volume and the interobserver agreement.

MethodsTwenty patients with biopsy proven T1-T4 supraglottic laryngeal cancer, treated with curative intent were included. For all patients a contrast enhanced planning CT and a 1.5-T MRI with gadolinium were acquired in the same head-and-shoulder mask for fixation as used during treatment. For MRI, a two element surface coil was used as a receiver coil. Three dedicated observers independently delineated the GTV on CT. After an interval of 2 weeks, a set of co-registered CT and MR-images was provided to delineate the GTV on CT. Common volumes C and encompassing volumes E were calculated and C-E ratios were determined for each pair of observers. The conformity index general CIgen was used to quantify the interobserver agreement. Results: In general, a large variation in interobserver agreement was found for CT range: 0.29-0.77 as well as for CT-MR delineations range: 0.17-0.80. The mean CIgen for CT 0.61 was larger compared to CT-MR 0.57 p = 0.032. Mean GTV volume delineated on CT-MR 6.6 cm was larger compared to CT 5.6 cm p = 0.002.

ConclusionDelineation on CT with co-registered MR-images resulted in a larger mean GTV volume and in a decrease in interobserver agreement compared to CT only delineation for supraglottic laryngeal carcinoma.

KeywordsInterobserver agreement Supraglottic laryngeal carcinoma Head-and-neck cancer GTV MRI Electronic supplementary materialThe online version of this article doi:10.1186-s13014-014-0321-4 contains supplementary material, which is available to authorized users.

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Author: Elise Anne Jager - Nicolien Kasperts - Joana Caldas-Magalhaes - Mariëlle EP Philippens - Frank A Pameijer - Chris HJ Te

Source: https://link.springer.com/



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