Reliability of NI-RADS criteria in the interpretation of contrast-enhanced magnetic resonance imaging considering the potential role of diffusion-weighted imaging

Fabian Henry Jürgen Elsholtz,Hans-Christian Bauknecht,Stefan Markus Niehues,Bernd Hamm,Patrick Dinkelborg,Kilian Kreutzer,Christoph Erxleben

doi:10.1007/s00330-021-07693-4

Abstract

ObjectivesTo assess inter- and intrareader agreement of the Neck Imaging Reporting and Data System (NI-RADS) used in contrast-enhanced magnetic resonance imaging (MRI) including analysis of diffusion-weighted imaging (DWI), which is currently not part of the NI-RADS criteria.MethodsThis retrospective study included anonymized surveillance contrast-enhanced MRI datasets of 104 patients treated for different head and neck cancers. Three radiologists experienced in head and neck imaging reported findings for the primary site and the neck using NI-RADS criteria in a first step and evaluated DWI sequences for the primary site in a second step. Thirty randomly selected imaging datasets were again presented to the readers. Kappa statistics and observed agreement (Ao) were calculated.ResultsInterreader agreement across all MRI datasets was moderate (κFleiss = 0.53) for NI-RADS categories assigned to the primary site, substantial for NI-RADS categories of the neck (κFleiss = 0.67), and almost perfect for DWI of the primary site (κFleiss = 0.83). Interreader agreement for the primary site was particularly low in cases of cancer recurrence (κFleiss = 0.35) and when categories 2a, 2b, and 3 were combined (κFleiss = 0.30). Intrareader agreement was considerably lower for NI-RADS categories of the primary site (range Ao = 53.3–70.0%) than for NI-RADS categories of the neck (range Ao = 83.3–90.0%) and DWI of the primary site (range Ao = 93.3–100.0%).ConclusionInterreader agreement of NI-RADS for reporting contrast-enhanced MRI findings is acceptable for the neck but limited for the primary site. Here, DWI has the potential to serve as a reliable additional criterion.Key Points• NI-RADS was originally designed for contrast-enhanced computed tomography with or without positron emission tomography but can also be used for contrast-enhanced magnetic resonance imaging alone.• Overall interreader agreement was acceptable for NI-RADS categories assigned to the neck but should be improved for the primary site, where it was inferior to DWI; similar tendencies were found for intrareader agreement.• DWI is currently no criterion of NI-RADS, but has shown potential to improve its reliability, especially for categories 2a, 2b, and 3 of the primary site.

Highlights

In the 2018 worldwide cancer statistics, head and neck (HN) cancer including malignancies of the thyroid gland accounted for 8% (1,454,892 patients) of all new cases and 5.2% (494,378) of all deaths [1]
Overall interreader agreement was acceptable for Neck Imaging Reporting and Data System” (NI-RADS) categories assigned to the neck but should be improved for the primary site, where it was inferior to diffusion-weighted imaging (DWI); similar tendencies were found for intrareader agreement
We searched our department’s database for suitable patients from all three sites of our hospital using the following inclusion criteria: (1) consecutive patients with available CEMRI datasets of the neck acquired for surveillance after curative treatment of HN cancer; (2) CEMRI datasets including (a) axial contrast-enhanced and fat-suppressed T1-weighted (T1w CE FS) sequences, (b) coronal and fat-suppressed T2weighted (T2w FS) sequences, (c) axial diffusion-weighted images with corresponding apparent diffusion coefficient (ADC) maps; (3) pretreatment or prior surveillance imaging datasets (CEMRI or contrast-enhanced computed tomography (CECT)) available; (4) availability of reports on either subsequent histopathology or subsequent surveillance imaging no earlier than 6 months later

Summary

Introduction

In the 2018 worldwide cancer statistics, head and neck (HN) cancer including malignancies of the thyroid gland accounted for 8% (1,454,892 patients) of all new cases and 5.2% (494,378) of all deaths [1]. While such reports allow radiologists to individually weight their findings, they can cause problems [3]. NI-RADS addresses the ACR’s imaging 3.0 strategy, which seeks to include clinical decision support directly from radiological reports by linking each category with a concrete recommendation for further patient handling such as shortening the interval until the imaging examination or performing a biopsy [10]. In this way, NI-RADS standardizes the entire surveillance program. Diffusion-weighted imaging, which has already established itself as a standard sequence in head and neck imaging, is not yet a criterion in NI-RADS [11]

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Methods

Results