Laurence Parker PhD, Abstract Co-Author: Nothing to Disclose

Courtney L. Hoey MD, Presenter: Nothing to Disclose

Eric Laurence Gingold PhD, Abstract Co-Author: Nothing to Disclose

Andrea J. Frangos MPH, Abstract Co-Author: Nothing to Disclose

Levon N. Nazarian MD, Abstract Co-Author: Nothing to Disclose

Since ultrasound (US) for appendicitis evaluation has high positive predictive value, low cost, and no radiation exposure, sending patients directly to surgery on a positive US offers potential savings. This study estimates the cost and radiation savings of such a protocol which avoids the use of computed tomography (CT) for some patients.

The primary data sources were the Center for Medicare and Medicaid Services 5% Carrier, Inpatient, and Beneficiary files and the Physician/Supplier Procedure Summary Master Files for 2007, which were used to determine the amount and costs of CT and US for appendicitis evaluation. National Center for Health Statistics and Agency for Healthcare Research and Quality hospital discharge surveys were used to estimate national incidence of appendicitis and abdominal pain. A meta-analysis of 85 recent studies was conducted to determine sensitivity and positive predictive value (PPV) of US and CT. Finally, a review of 30 consecutive patients at our institution who had abdominal and pelvic CTs was used to estimate radiation exposure.

In the 5% Medicare sample of 1.85 M. beneficiaries, 645 patients had appendicitis admissions, with 1288 CTs of the abdomen and pelvis, almost exactly one of each per person. There were 863 admissions for right lower quadrant pain. Allowed charges for abdominal and pelvic CTs averaged $192 per patient vs. $39 for a limited US exam. National hospital discharge survey estimates for appendicitis are about 295,000 cases per year. Meta-analysis estimated US sensitivity at 87.5% and PPV at 91.0%. In an algorithm which sent appendicitis and lower right quadrant pain patients directly to surgery after a positive US, 258,049 abdominal and pelvic CTs would be avoided nationally, saving $49 M. per year over the cost of an additional 691,992 limited US exams. Radiation exposure from a combined abdominal and pelvic CT was estimated at 12.4 mSv. Applying the BEIR VII model of the effects of low levels of ionizing radiation in a linear extrapolation, 182 excess cancer deaths per year would be saved nationally.

Our results show substantial cost and radiation savings in using US as a positive predictor of appendicitis. While our results are subject to the usual limitations of economic projection studies, such as the generalizability of different samples, they suggest that a prospective trial is warranted.

N.A.

Parker, L, Hoey, C, Gingold, E, Frangos, A, Nazarian, L, Cost and Radiation Savings of Partial Substitution of Ultrasound for Computed Tomography in Appendicitis Evaluation: A National Projection.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9011700.html