Rapid CT Diagnosis of Acute Appendicitis with IV

Contrast Material

S Mun*, K Chen*, S Shah*, A Oto*,S Mun*, K Chen*, S Shah*, A Oto*,

W Mileski**, L Swischuk*, R Ernst*W Mileski**, L Swischuk*, R Ernst*

Dept. of Radiology* and Surgery**Dept. of Radiology* and Surgery**

The University of Texas Medical BranchThe University of Texas Medical Branch

Background• Controversy exists regarding the optimal use of Controversy exists regarding the optimal use of

IV, oral and rectal contrast in CT evaluation of IV, oral and rectal contrast in CT evaluation of suspected acute appendicitissuspected acute appendicitis

• Some studies advocate non-oral contrast CT Some studies advocate non-oral contrast CT Lane et al; Malone et al; Peck et al; Stacher et al; Yuksekkaya et alLane et al; Malone et al; Peck et al; Stacher et al; Yuksekkaya et al

• UTMB ED CT protocol was designed to UTMB ED CT protocol was designed to accommodate high volume of patients accommodate high volume of patients requiring CT evaluation. requiring CT evaluation. Only IV contrastOnly IV contrast enhanced CT is utilized to aid in the diagnosis enhanced CT is utilized to aid in the diagnosis of suspected appendicitisof suspected appendicitis

Purpose

• To determine retrospectively the To determine retrospectively the sensitivity and specificity of IV contrast sensitivity and specificity of IV contrast enhanced CT without oral contrast in enhanced CT without oral contrast in confirming suspected acute appendicitis confirming suspected acute appendicitis

Materials and Methods• Patients studies were retrieved over an 8 month Patients studies were retrieved over an 8 month

period (after institution of ED CT protocol) by a period (after institution of ED CT protocol) by a computer-generated search for “appendicitis” in the computer-generated search for “appendicitis” in the radiology reportsradiology reports

• Studies with oral contrast, and without IV contrast Studies with oral contrast, and without IV contrast were excludedwere excluded

• Patients age 17 and older with CT scans performed Patients age 17 and older with CT scans performed with IV contrast only were included in the study with IV contrast only were included in the study populationpopulation

Materials and Methods

• Reports of all patients were reviewed Reports of all patients were reviewed retrospectivelyretrospectively

• Pathology reports and medical records were Pathology reports and medical records were reviewedreviewed

• Patients without a histopathologic diagnosis of Patients without a histopathologic diagnosis of appendicitis who had no documented clinical appendicitis who had no documented clinical follow-up of 1 week were excludedfollow-up of 1 week were excluded

• Patients with indeterminate reports excludedPatients with indeterminate reports excluded

Materials and Methods

• Results of CT reports were compared with Results of CT reports were compared with clinical/pathology reportsclinical/pathology reports

• Sensitivity, specificity, positive predictive value Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were (PPV), and negative predictive value (NPV) were calculatedcalculated

Results

• 271 patients were initially retrieved from the 271 patients were initially retrieved from the radiology report databaseradiology report database

• 59 patients were excluded59 patients were excluded Unenhanced or oral contrast studies (n=54)Unenhanced or oral contrast studies (n=54) Pediatric patients (n=5)Pediatric patients (n=5)

• 212 patients were included212 patients were included– Lost to follow-up (n=35) (16.5%)Lost to follow-up (n=35) (16.5%)– Indeterminate cases, rescanned (n=4) (2.2%)Indeterminate cases, rescanned (n=4) (2.2%)

N= 173N= 173 Final study populationFinal study population

Results

• Appendicitis was confirmed in 56 patients Appendicitis was confirmed in 56 patients (32.4%)(32.4%)

• Alternative diagnoses n=34 (19.6%)Alternative diagnoses n=34 (19.6%) Enteritis/colitis (n=9) Enteritis/colitis (n=9) Acute gynecologic disorder (n=9)Acute gynecologic disorder (n=9) Diverticulitis (n=5)Diverticulitis (n=5) Urinary tract infection (n=4)Urinary tract infection (n=4) Cholecystitis (n=4)Cholecystitis (n=4) Malignant neoplastic disease (n=3)Malignant neoplastic disease (n=3)

• Pain subsided without specific diagnosis Pain subsided without specific diagnosis (n=80) (46.2%)(n=80) (46.2%)

Results

Clinical or histopathologic Clinical or histopathologic outcomeoutcome

Appendicitis Appendicitis positivepositive

Appendicitis Appendicitis negativenegative

CTCT

positivepositive 5656 33

negativenegative 00 114114

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

ImagesInflamed appendix

DiverticulitisDiverticulitis

ImagesCholecystitis

Images

Pyelonephritis

Limitations

• Some patients were lost to follow up, so Some patients were lost to follow up, so excluded from the studyexcluded from the study

• Computer-generated search for the word Computer-generated search for the word “appendicitis” may not have retrieved all “appendicitis” may not have retrieved all patients presenting with RLQ painpatients presenting with RLQ pain

• Acute appendicitis may have resolved Acute appendicitis may have resolved with non-surgical treatmentwith non-surgical treatment

Conclusions

• IV contrast-enhanced helical CT without IV contrast-enhanced helical CT without oral contrast material is a highly sensitive oral contrast material is a highly sensitive and specific technique for confirmation of and specific technique for confirmation of suspected acute appendicitissuspected acute appendicitis

• E D waiting time and patient delay to E D waiting time and patient delay to diagnosis may be improved diagnosis may be improved