Feasibility Study of Low Dose Chest CT for Initial Evaluation of Blunt Chest Trauma Patient

INTRODUCTION: Multi-detector computed tomography (MDCT) is now modality of choice for evaluation of the polytrauma patients including thoracic injury. However, the routine use of CT results in rapid increase of the CT radiation dose in blunt chest trauma evaluation. Therefore, according to the ALARA (as low as reasonable achievable) principle, radiation dose adjustment in the patients with blunt chest trauma is inevitable. We aimed to evaluate the diagnostic performance and inter-observer consistency of low-dose chest CT (LDCT) in the patients with blunt chest trauma. MATERIALS AND METHODS: A total of 69 patients who met criteria indicative of blunt chest trauma (77% of male; age range, 16-85) were prospectively included. All patients underwent LDCT without intravenous (IV) contrast and standard-dose chest CT (SDCT) with IV contrast using parameters as followings: LDCT, 40mAs with automatic tube current modulation (ATCM) and 100kVp (body mass index (BMI) <25, n=51) or 120kVp (BMI>25, n=18); SDCT, 180mAs with ATCM and 120kVp. Transverse, coronal, saggital images were reconstructed with 3-mm slice thickness without gap for investigators. Reference standard images (transverse, coronal, saggital) were reconstructed using standard chest CT data with 1-mm slice thickness without gap. Reference standard was established by 2 experienced thoracic radiologist by consensus. Three investigators independently evaluated blunt chest injury (pulmonary and tracheobronchial injury, skeletal trauma, mediastinal injury, chest wall injury, diaphragmatic injury, aortic injury and upper abdominal injury). Investigators recorded results with 4 confidence scale (0-3 point). Comparison of radiation dose was done by vendor providing CT dose index volume (CTDIvol). RESULTS: Radiation dose of LDCT (average CTDIvol = 2.72mGy) was significantly lower than those of SDCT (average CTDIvol = 13.4mGy) (79.4% dose reduction). Multiple-reader receiver operating characteristic (ROC) analysis for comparing areas under the ROC curves (AUC) demonstrated that LDCT was comparable to SDCT for evaluation of blunt chest injury (AUC in LDCT : 0.823-1.000, AUC in SDCT : 0.781-1.000, p>0.05). ROC comparison analysis revealed no significant difference of diagnostic performance between LDCT and SDCT for the diagnosis of pulmonary injury, skeletal trauma, mediastinal injury and chest wall injury (p>0.05). Intraclass correlation coefficient (ICC) was measured for inter-observer consistency and revealed that there was good inter-observer consistency in each examination of LDCT and SDCT for evaluation of blunt chest injury (0.8601~1.000). Aortic and upper abdominal injury could not be appropriately compared due to LDCT underwent without using contrast materials and this was limitation of this study. CONCLUSION: Our conclusion is that there is a great potential benefit to use of LDCT for initial evaluation of blunt chest trauma because LDCT could maintain diagnostic image quality as SDCT and provide significant radiation dose reduction. Further study of LDCT with IV contrast for evaluation of aortic and upper abdominal injury is needed.

Author dc:creator

• 김, 성중

Contributors dc:contributor

• 선, 주성
• 대학원 의학과
• 201224096

• Low dose chest CT
• Blunt chest trauma
• Diagnostic performance
• Radiation dose reduction
• 저선량 흉부 CT
• 흉부 외상
• 진단능
• 방사선량 감소

Language dc:language

en

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000017388
000000017388

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/10937