Practical guidelines for handling head and neck computed tomography artifacts for quantitative image analysis

• Published in: Computerized medical imaging and graphics Vol. 69; pp. 134 - 139
• Main Authors: Ger, Rachel B., Craft, Daniel F., Mackin, Dennis S., Zhou, Shouhao, Layman, Rick R., Jones, A. Kyle, Elhalawani, Hesham, Fuller, Clifton D., Howell, Rebecca M., Li, Heng, Stafford, R. Jason, Court, Laurence E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.11.2018; Elsevier Science Ltd
• Subjects: Adult; Aged; Algorithms; Cancer; Cartridges; Chlorides; Computation; Computed tomography; Computer simulation; Dental fillings; Dental materials; Female; Hardening; Head & neck cancer; Head and neck; Head and Neck Neoplasms - diagnostic imaging; Histopathology; Humans; Image analysis; Image Interpretation, Computer-Assisted - methods; Image processing; Male; Medical imaging; Middle Aged; Patients; Phantoms, Imaging; Polylactic acid; Polystyrene; Polystyrene resins; Polyvinyl chloride; Quantitative imaging; Radiomics; Texture; Tomography; Tomography, X-Ray Computed; Head and neck; Artifacts; Quantitative imaging; Texture; Radiomics
• ISSN: 0895-6111; 1879-0771
• DOI: 10.1016/j.compmedimag.2018.09.002

•Head and neck patients are often affected by streak and beam hardening artifacts, impacting their inclusion in studies.•Streak artifacts impact the majority of radiomics features’ values.•Contours of structures can abut bone without affecting most radiomics features’ values if needed.•Most features were robust with up to 50% of the original tumor volume removed.•More patients’ head and neck CTs can be used in radiomics studies by simply removing slices affected by streak artifacts. Radiomics studies have demonstrated the potential use of quantitative image features to improve prognostic stratification of patients with head and neck cancer. Imaging protocol parameters that can affect radiomics feature values have been investigated, but the effects of artifacts caused by intrinsic patient factors have not. Two such artifacts that are common in patients with head and neck cancer are streak artifacts caused by dental fillings and beam-hardening artifacts caused by bone. The purpose of this study was to test the impact of these artifacts and if needed, methods for compensating for these artifacts in head and neck radiomics studies. The robustness of feature values was tested by removing slices of the gross tumor volume (GTV) on computed tomography images from 30 patients with head and neck cancer; these images did not have streak artifacts or had artifacts far from the GTV. The range of each feature value over a percentage of the GTV was compared to the inter-patient variability at full volume. To determine the effects of beam-hardening artifacts, we scanned a phantom with 5 cartridges of different materials encased in polystyrene buildup. A cylindrical hole through the cartridges contained either a rod of polylactic acid to simulate water or a rod of polyvinyl chloride to simulate bone. A region of interest was drawn in each cartridge flush with the rod. Most features were robust with up to 50% of the original GTV removed. Most feature values did not significantly differ when measured with the polylactic acid rod or the polyvinyl chloride rod. Of those that did, the size of the difference did not exceed the inter-patient standard deviation in most cases. We conclude that simply removing slices affected by streak artifacts can enable these scans to be included in radiomics studies and that contours of structures can abut bone without being affected by beam hardening if needed.