Appendiceal Visualization on 2-mSv CT vs. Conventional-Dose CT in Adolescents and Young Adults with Suspected Appendicitis: An Analysis of Large Pragmatic Randomized Trial Data

• Published in: Korean journal of radiology Vol. 23; no. 4; pp. 413 - 425
• Main Authors: Cho, Jungheum, Kim, Youngjune, Lee, Seungjae, Min, Hooney Daniel, Ko, Yousun, Chee, Choong Guen, Kim, Hae Young, Park, Ji Hoon, Lee, Kyoung Ho
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Society of Radiology 01.04.2022; 대한영상의학회
• Subjects: Abscesses; Adolescent; Adult; Appendectomy; Appendicitis; Appendicitis - diagnostic imaging; Appendicitis - surgery; Appendix - diagnostic imaging; Diagnostic tests; Emergency medical care; Female; Gastrointestinal Imaging; Humans; Likert scale; Patients; Physicians; Radiation; Radiologists; Surgery; Teenagers; Tomography, X-Ray Computed - methods; Ultrasonic imaging; Visualization; Young Adult; Young adults; 방사선과학; South Korea; Tomography, X-ray computed; Appendicitis; Radiation dosage; Abdomen
• ISSN: 1229-6929; 2005-8330
• DOI: 10.3348/kjr.2021.0504

We compared appendiceal visualization on 2-mSv CT vs. conventional-dose CT (median 7 mSv) in adolescents and young adults and analyzed the undesirable clinical and diagnostic outcomes that followed appendiceal nonvisualization. A total of 3074 patients aged 15-44 years (mean ± standard deviation, 28 ± 9 years; 1672 female) from 20 hospitals were randomized to the 2-mSv CT or conventional-dose CT group (1535 vs. 1539) from December 2013 through August 2016. A total of 161 radiologists from 20 institutions prospectively rated appendiceal visualization (grade 0, not identified; grade 1, unsure or partly visualized; and grade 2, clearly and entirely visualized) and the presence of appendicitis in these patients. The final diagnosis was based on CT imaging and surgical, pathologic, and clinical findings. We analyzed undesirable clinical or diagnostic outcomes, such as negative appendectomy, perforated appendicitis, more extensive than simple appendectomy, delay in patient management, or incorrect CT diagnosis, which followed appendiceal nonvisualization (defined as grade 0 or 1) and compared the outcomes between the two groups. In the 2-mSv CT and conventional-dose CT groups, appendiceal visualization was rated as grade 0 in 41 (2.7%) and 18 (1.2%) patients, respectively; grade 1 in 181 (11.8%) and 81 (5.3%) patients, respectively; and grade 2 in 1304 (85.0%) and 1421 (92.3%) patients, respectively ( < 0.001). Overall, undesirable outcomes were rare in both groups. Compared to the conventional-dose CT group, the 2-mSv CT group had slightly higher rates of perforated appendicitis (1.1% [17] vs. 0.5% [7], = 0.06) and false-negative diagnoses (0.4% [6] vs. 0.0% [0], = 0.01) following appendiceal nonvisualization. Otherwise, these two groups were comparable. The use of 2-mSv CT instead of conventional-dose CT impairs appendiceal visualization in more patients. However, appendiceal nonvisualization on 2-mSv CT rarely leads to undesirable clinical or diagnostic outcomes.