382 AJR:212, February 2019 Leslie K. Lee 1,2 Andrew T. Reisner 3 William D. Binder 3,4 Atif Zaheer 5 Martin L. Gunn 6 Ken F. Linnau 6 Chad M. Miller 7 Maurice S. Herring 1,8,9 Angela C. Tramontano 8 Avinash Kambadakone 1 Onofrio A. Catalano 1 Mukesh Harisinghani 1 Elkan F. Halpern 1,8 Karen Donelan 10 G. Scott Gazelle 1,8 Pari V. Pandharipande 1,8 Lee LK, Reisner AT, Binder WD, et al. increase in CT utilization (relative risk, 9.97 and 9.24, respectively) [2, 3]. Repeat CT scans represent a large proportion of abdominal CT scans obtained in the ED. In a single-institution study performed from 2007 to 2010, Nojkov et al. [4] reported that 53% of CT examinations for nontraumatic abdominal pain were frst- time (i.e., index) examinations, whereas 47% were repeat CT examinations; in addition, they Repeat CT Performed Within One Month of CT Conducted in the Emergency Department for Abdominal Pain: A Secondary Analysis of Data From a Prospective Multicenter Study Health Care Policy and Quality • Original Research This article is available for credit. AJR 2019; 212:382–385 0361–803X/19/2122–382 © American Roentgen Ray Society N ontraumatic abdominal pain is the most common complaint of pa- tients seen in the emergency de- partment (ED), and it is the com- plaint most frequently associated with referral for CT [1]. Moreover, among the 20 most com- mon indications for referral for CT in the ED from 1996 to 2007 in the United States, abdom- inal pain and fank pain had the highest rates of Keywords: abdominal pain, CT, emergency medicine, health policy, resource utilization doi.org/10.2214/AJR.18.20060 Received April 26, 2018; accepted after revision July 18, 2018. M. L. Gunn receives grant support from Philips Healthcare; G. S. Gazelle is a consultant to GE Healthcare; K. F. Linnau is a paid continuing medical education speaker for Siemens Healthcare and receives publishing royalties from Cambridge Press; A. T. Reisner receives grant support from Nihon Kohden Corporation and is a consultant to Boehringer Ingelheim. P. V. Pandharipande, A. T. Reisner, W. D. Binder, A. Zaheer, M. L. Gunn, K. F. Linnau, C. M. Miller, M. S. Herring, A. C. Tramontano, and K. Donelan received support from the grant from the National Electrical Manufacturers Association during the study. The content is solely the responsibility of the authors and does not necessarily represent the of fcial views of the National Electrical Manufacturers Association (NEMA) or the Medical Imaging and Technology Alliance, a division of NEMA. The design and conduct of the study; collection, storage, management, analysis, and interpretation of the data; preparation and approval of the manuscript; and decision to submit the manuscript for publication was at the sole discretion of the authors, and not the sponsor. The sponsor had the opportunity to review the manuscript; incorporation of the sponsor’s comments on the research was at the sole discretion of the authors. Based on a presentation at the Radiological Society of North America 2016 annual meeting, Chicago, IL. Supported by a grant from the National Electrical Manufacturers Association. 1 Department of Radiology, Massachusetts General Hospital, 55 Fruit St, Boston, MA 02114. Address correspondence to P. V. Pandharipande (pari@mgh-ita.org). 2 Present address: Department of Radiology, Brigham and Women’s Hospital, Boston, MA. 3 Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA. 4 Present address: Department of Emergency Medicine, Brown University, Providence, RI. 5 Department of Radiology, Johns Hopkins University, Baltimore, MD. 6 Department of Radiology, University of Washington, Seattle, WA. 7 Department of Radiology, Duke University Medical Center, Durham, NC. 8 Institute for Technology Assessment, Massachusetts General Hospital, Boston, MA. 9 Present address: Cedars Sinai Medical Center, Los Angeles, CA. 10 Department of Medicine, Mongan Institute for Health Policy Center, Massachusetts General Hospital, Boston, MA. OBJECTIVE. The purpose of this study is to determine both the frequency of repeat CT performed within 1 month after a patient visits the emergency department (ED) and undergoes CT evaluation for abdominal pain and the frequency of worsened or new CT-based diagnoses. SUBJECTS AND METHODS. Secondary analysis was performed on data collected dur- ing a prospective multicenter study. The parent study included patients who underwent CT in the ED for abdominal pain between 2012 and 2014, and these patients constituted the study group of the present analysis. The proportion of patients who underwent (in any setting) repeat abdominal CT within 1 month of the index CT examination was calculated. For each of these patients, results of the index and repeat CT scans were compared by an independent panel and categorized as fol- lows: no change (group 1); same process, improved (group 2); same process, worse (group 3); or different process (group 4). The proportion of patients in groups 1 and 2 versus groups 3 and 4 was calculated, and patient and ED physician characteristics were compared. RESULTS. The parent study included 544 patients (246 of whom were men [45%]; mean pa- tient age, 49.4 years). Of those 544 patients, 53 (10%; 95% CI, 7.5–13%) underwent repeat abdomi- nal CT. Patients’ CT comparisons were categorized as follows: group 1 for 43% of patients (23/53), group 2 for 26% (14/53), group 3 for 15% (8/53), and group 4 for 15% (8/53). New or worse fndings were present in 30% of patients (16/53) (95% CI, 19–44%). When patients with fndings in groups 1 and 2 were compared to patients with fndings in groups 3 and 4, no signifcant difference was noted in patient age (p = 0.25) or sex (p = 0.76), the number of days between scans (p = 0.98), and the diagnostic confdence of the ED physician after the index CT scan was obtained (p = 0.33). CONCLUSION. Short-term, repeat abdominal CT was performed for 10% of patients who underwent CT in the ED for abdominal pain, and it yielded new or worse fndings for 30% of those patients. Lee et al. Repeat CT for Abdominal Pain Health Care Policy and Quality Original Research Downloaded from www.ajronline.org by 3.236.109.246 on 03/11/22 from IP address 3.236.109.246. Copyright ARRS. For personal use only; all rights reserved