Adrenal lesions: variability in attenuation over time, between scanners, and between observers
| Autor: | Lilian Hammarstedt, Anders Odén, Anne Thilander-Klang, Andreas Muth, Mikael Hellström, Bo Wängberg |
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| Rok vydání: | 2013 |
| Předmět: |
Change over time
Adult Male medicine.medical_specialty media_common.quotation_subject Adrenal Gland Neoplasm Adrenal Gland Diseases Computed tomography Imaging phantom Statistics Nonparametric Hounsfield scale Medicine Contrast (vision) Humans Radiology Nuclear Medicine and imaging Prospective Studies media_common Ultrasonography Incidental Findings Radiological and Ultrasound Technology medicine.diagnostic_test business.industry Phantoms Imaging Attenuation Reproducibility of Results General Medicine Magnetic Resonance Imaging Contrast medium Radiographic Image Interpretation Computer-Assisted Female Radiology business Nuclear medicine Tomography X-Ray Computed Software |
| Zdroj: | Acta radiologica (Stockholm, Sweden : 1987). 54(7) |
| ISSN: | 1600-0455 |
| Popis: | Background Measurements of attenuation (in Hounsfield units [HU]) and contrast wash-out are widely used to characterize adrenal lesions as benign or indeterminate/malignant at computed tomography (CT). Clinical experience suggests that such measurements of adrenal lesions may vary over time and between observers, making evaluation difficult. Purpose To investigate the change over time of adrenal lesion size, attenuation, and contrast wash-out at CT, to determine inter-observer variability, and to analyze other factors underlying the variability. Material and Methods In a cohort of patients, with or without malignant disease, undergoing CT, adrenal lesions were prospectively analyzed. Lesions with growth >20% or >5 mm over 6 months were excluded. Non-enhanced attenuation and contrast medium wash-out over 2-year follow-up were analyzed. An inter-observer analysis with five observers and a phantom study of eight different CT scanners were performed to assess measurement variability. Results Mean adrenal lesion non-enhanced attenuation values decreased by 0.5 HU/year during follow-up. Using 10 HU or 40% relative wash-out as threshold values for benign versus indeterminate lesions, 27 (20%) and 39 (29%) of 136 lesions, respectively, would be reclassified at some occasion during follow-up. In the observer analysis 37 of 40 lesions demonstrated agreement between all observers, using established threshold values. The phantom study showed an intra-scanner variability of 1–3 HU, but an inter-scanner variability of up to 8 HU for water. Conclusion The clinically widespread use of specific attenuation threshold values for characterizing adrenal lesions must be used with great caution, considering that multiple factors, related to patient, equipment, scanning technique, and observer influence the outcome. |
| Databáze: | OpenAIRE |
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