N Sakai1, H Yabuuchi1, M Kondo2, Y Matsuo3, T Kamitani3, M Nagao3, M Jinnouchi3, M Yonezawa3, T Kojima1, Y Yano1, H Honda3. 1. 1 Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. 2. 2 Division of Radiological Technology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan. 3. 3 Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Abstract
OBJECTIVE: To evaluate the confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose screening CT with hybrid iterative reconstruction (IR). METHODS: Simulated lesions (emphysema, mediastinal masses and interstitial pneumonia) in a chest phantom were scanned by a 320-row area detector CT. The scans were performed by 64-row and 160-row helical scans at various dose levels and were reconstructed by filtered back projection (FBP) and IR. Emphysema, honeycombing and reticular opacity were visually scored on a four-point scale by six thoracic radiologists. The ground-glass opacity as a percentage of total lung volume (%GGO), CT value and contrast-to-noise ratio (CNR) of mediastinal masses were calculated. These scores and values were compared between FBP and IR. Wilcoxon's signed-rank test was used (p < 0.05). Interobserver agreements were evaluated by κ statistics. RESULTS: There were no significant differences in visual assessment. Interobserver agreement was almost perfect. CT values were almost equivalent between FBP and IR, whereas CNR with IR was significantly higher than that with FBP. %GGO significantly increased at low-dose levels with FBP; however, IR suppressed the elevation. CONCLUSION: The confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose CT screening were not degraded with hybrid IR compared with FBP. ADVANCES IN KNOWLEDGE: Hybrid IR did not degrade the confidence ratings of diagnoses on visual assessment and differential diagnoses based on CT value of mediastinal masses, and it showed the advantage of higher GGO conspicuity at low-dose level. Radiologists can analyse images of hybrid IR alone on low-dose CT screening for lung cancer.
OBJECTIVE: To evaluate the confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose screening CT with hybrid iterative reconstruction (IR). METHODS: Simulated lesions (emphysema, mediastinal masses and interstitial pneumonia) in a chest phantom were scanned by a 320-row area detector CT. The scans were performed by 64-row and 160-row helical scans at various dose levels and were reconstructed by filtered back projection (FBP) and IR. Emphysema, honeycombing and reticular opacity were visually scored on a four-point scale by six thoracic radiologists. The ground-glass opacity as a percentage of total lung volume (%GGO), CT value and contrast-to-noise ratio (CNR) of mediastinal masses were calculated. These scores and values were compared between FBP and IR. Wilcoxon's signed-rank test was used (p < 0.05). Interobserver agreements were evaluated by κ statistics. RESULTS: There were no significant differences in visual assessment. Interobserver agreement was almost perfect. CT values were almost equivalent between FBP and IR, whereas CNR with IR was significantly higher than that with FBP. %GGO significantly increased at low-dose levels with FBP; however, IR suppressed the elevation. CONCLUSION: The confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose CT screening were not degraded with hybrid IR compared with FBP. ADVANCES IN KNOWLEDGE: Hybrid IR did not degrade the confidence ratings of diagnoses on visual assessment and differential diagnoses based on CT value of mediastinal masses, and it showed the advantage of higher GGO conspicuity at low-dose level. Radiologists can analyse images of hybrid IR alone on low-dose CT screening for lung cancer.
Authors: H Yabuuchi; Y Matsuo; H Tsukamoto; T Horiuchi; S Sunami; T Kamitani; M Jinnouchi; M Nagao; K Akashi; H Honda Journal: Clin Radiol Date: 2014-05-10 Impact factor: 2.350
Authors: Y Yano; H Yabuuchi; A Kairada; N Tanaka; J Morishita; T Akasaka; Y Matsuo; T Kamitani; Y Yamasaki; M Nagao; M Sasaki Journal: Br J Radiol Date: 2014-05-29 Impact factor: 3.039
Authors: Mathilde M W Wille; Laura H Thomsen; Jens Petersen; Marleen de Bruijne; Asger Dirksen; Jesper H Pedersen; Saher B Shaker Journal: Eur Radiol Date: 2015-05-09 Impact factor: 5.315