1. Rapid CT Diagnosis of Acute Appendicitis with IV Contrast Material S Mun*, K Chen*, S Shah*, A Oto*, W Mileski**, L Swischuk*, R Ernst* Dept. of Radiology* and Surgery** The University of Texas Medical Branch

2. Background Controversy exists regarding the optimal use of IV, oral and rectal contrast in CT evaluation of suspected acute appendicitisControversy exists regarding the optimal use of IV, oral and rectal contrast in CT evaluation of suspected acute appendicitis Some studies advocate non-oral contrast CT Lane et al; Malone et al; Peck et al; Stacher et al; Yuksekkaya et alSome studies advocate non-oral contrast CT Lane et al; Malone et al; Peck et al; Stacher et al; Yuksekkaya et al UTMB ED CT protocol was designed to accommodate high volume of patients requiring CT evaluation. Only IV contrast enhanced CT is utilized to aid in the diagnosis of suspected appendicitisUTMB ED CT protocol was designed to accommodate high volume of patients requiring CT evaluation. Only IV contrast enhanced CT is utilized to aid in the diagnosis of suspected appendicitis

3. Purpose To determine retrospectively the sensitivity and specificity of IV contrast enhanced CT without oral contrast in confirming suspected acute appendicitisTo determine retrospectively the sensitivity and specificity of IV contrast enhanced CT without oral contrast in confirming suspected acute appendicitis

4. Materials and Methods Patients studies were retrieved over an 8 month period (after institution of ED CT protocol) by a computer-generated search for “appendicitis” in the radiology reportsPatients studies were retrieved over an 8 month period (after institution of ED CT protocol) by a computer-generated search for “appendicitis” in the radiology reports Studies with oral contrast, and without IV contrast were excludedStudies with oral contrast, and without IV contrast were excluded Patients age 17 and older with CT scans performed with IV contrast only were included in the study populationPatients age 17 and older with CT scans performed with IV contrast only were included in the study population

5. Materials and Methods Reports of all patients were reviewed retrospectivelyReports of all patients were reviewed retrospectively Pathology reports and medical records were reviewedPathology reports and medical records were reviewed Patients without a histopathologic diagnosis of appendicitis who had no documented clinical follow-up of 1 week were excludedPatients without a histopathologic diagnosis of appendicitis who had no documented clinical follow-up of 1 week were excluded Patients with indeterminate reports excludedPatients with indeterminate reports excluded

6. Materials and Methods Results of CT reports were compared with clinical/pathology reportsResults of CT reports were compared with clinical/pathology reports Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculatedSensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated

7. Results 271 patients were initially retrieved from the radiology report database271 patients were initially retrieved from the radiology report database 59 patients were excluded59 patients were excluded  Unenhanced or oral contrast studies (n=54)  Pediatric patients (n=5) 212 patients were included212 patients were included –Lost to follow-up (n=35) (16.5%) –Indeterminate cases, rescanned (n=4) (2.2%)  N= 173Final study population

8. Results Appendicitis was confirmed in 56 patients (32.4%)Appendicitis was confirmed in 56 patients (32.4%) Alternative diagnoses n=34 (19.6%)Alternative diagnoses n=34 (19.6%)  Enteritis/colitis (n=9)  Acute gynecologic disorder (n=9)  Diverticulitis (n=5)  Urinary tract infection (n=4)  Cholecystitis (n=4)  Malignant neoplastic disease (n=3) Pain subsided without specific diagnosis (n=80) (46.2%)Pain subsided without specific diagnosis (n=80) (46.2%)

9. Results Clinical or histopathologic outcome Appendicitis positive Appendicitis negative CTpositive563 negative0114

10. Results Sensitivity 100%Sensitivity 100% Specificity 97%Specificity 97% Positive predictive value 95%Positive predictive value 95% Negative predictive value 100%Negative predictive value 100% Time savings are approximately 1 hourTime savings are approximately 1 hour

11. Images Inflamed appendix

12. Diverticulitis

13. Images Cholecystitis

14. Images Pyelonephritis

15. Limitations Some patients were lost to follow up, so excluded from the studySome patients were lost to follow up, so excluded from the study Computer-generated search for the word “appendicitis” may not have retrieved all patients presenting with RLQ painComputer-generated search for the word “appendicitis” may not have retrieved all patients presenting with RLQ pain Acute appendicitis may have resolved with non-surgical treatmentAcute appendicitis may have resolved with non-surgical treatment

16. Conclusions IV contrast-enhanced helical CT without oral contrast material is a highly sensitive and specific technique for confirmation of suspected acute appendicitisIV contrast-enhanced helical CT without oral contrast material is a highly sensitive and specific technique for confirmation of suspected acute appendicitis E D waiting time and patient delay to diagnosis may be improvedE D waiting time and patient delay to diagnosis may be improved