Christina Söderman1, Åse A Johnsson2, Jenny Vikgren2, Rauni R Norrlund2, David Molnar3, Angelica Svalkvist4, Lars G Månsson5, Magnus Båth5. 1. Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-41345 Gothenburg, Sweden. Electronic address: christina.e.soderman@vgregion.se. 2. Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden. 3. Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden. 4. Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden. 5. Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-41345 Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden.
Abstract
RATIONALE AND OBJECTIVES: To investigate the accuracy and precision of pulmonary nodule size measurements on chest tomosynthesis images. MATERIALS AND METHODS: Artificial ellipsoid-shaped nodules with known sizes were inserted in clinical chest tomosynthesis images. The volume of the nodules corresponded to that of a sphere with a diameter of 4.0, 8.0, or 12.0 mm. Four thoracic radiologists were given the task to determine the longest diameter of the nodules. All nodules were measured twice. Measurement accuracy in terms of the mean measurement error was determined. Intraobserver and interobserver variabilities, as well as variability because of differences between nodules and their locations, were used as measures of precision. RESULTS: The mean measurement error ranged from -0.3 to 0.1 mm for the nodule size groups and observers. Of the smallest nodules, the observers found 7-17 of total 50 nodules nonmeasurable. The intraobserver and interobserver variabilities were of similar magnitude, indicating relatively small differences between the observers. The internodule variability was in general larger, indicating that the different characteristics of the nodules and their location are sources of variability. CONCLUSIONS: The results suggest a high accuracy and precision for manual measurements of the nodules in chest tomosynthesis images. However, small nodules (<5.0 mm) may be difficult to measure at all because of poor visibility.
RATIONALE AND OBJECTIVES: To investigate the accuracy and precision of pulmonary nodule size measurements on chest tomosynthesis images. MATERIALS AND METHODS: Artificial ellipsoid-shaped nodules with known sizes were inserted in clinical chest tomosynthesis images. The volume of the nodules corresponded to that of a sphere with a diameter of 4.0, 8.0, or 12.0 mm. Four thoracic radiologists were given the task to determine the longest diameter of the nodules. All nodules were measured twice. Measurement accuracy in terms of the mean measurement error was determined. Intraobserver and interobserver variabilities, as well as variability because of differences between nodules and their locations, were used as measures of precision. RESULTS: The mean measurement error ranged from -0.3 to 0.1 mm for the nodule size groups and observers. Of the smallest nodules, the observers found 7-17 of total 50 nodules nonmeasurable. The intraobserver and interobserver variabilities were of similar magnitude, indicating relatively small differences between the observers. The internodule variability was in general larger, indicating that the different characteristics of the nodules and their location are sources of variability. CONCLUSIONS: The results suggest a high accuracy and precision for manual measurements of the nodules in chest tomosynthesis images. However, small nodules (<5.0 mm) may be difficult to measure at all because of poor visibility.
Authors: Mishal Mendiratta-Lala; William Masch; Prasad R Shankar; Holly E Hartman; Matthew S Davenport; Matthew J Schipper; Chris Maurino; Kyle C Cuneo; Theodore S Lawrence; Dawn Owen Journal: Int J Radiat Oncol Biol Phys Date: 2018-09-10 Impact factor: 7.038