Rapid CT Diagnosis of Acute Appendicitis with IV Contrast Material

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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

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Background

• Controversy 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 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 appendicitis

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Purpose

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

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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 reports
• Studies 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
  population

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Materials and Methods

• Reports of all patients were reviewed
  retrospectively
• Pathology reports and medical records were
  reviewed
• Patients without a histopathologic diagnosis of
  appendicitis who had no documented clinical
  follow-up of 1 week were excluded
• Patients with indeterminate reports excluded

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Materials and Methods

• Results of CT reports were compared with
  clinical/pathology reports
• Sensitivity, specificity, positive predictive
  value (PPV), and negative predictive value (NPV)
  were calculated

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Results

• 271 patients were initially retrieved from the
  radiology report database
• 59 patients were excluded
• Unenhanced or oral contrast studies (n54)
• Pediatric patients (n5)
• 212 patients were included
• Lost to follow-up (n35) (16.5)
• Indeterminate cases, rescanned (n4) (2.2)
• N 173 Final study population

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Results

• Appendicitis was confirmed in 56 patients (32.4)
• Alternative diagnoses n34 (19.6)
• Enteritis/colitis (n9)
• Acute gynecologic disorder (n9)
• Diverticulitis (n5)
• Urinary tract infection (n4)
• Cholecystitis (n4)
• Malignant neoplastic disease (n3)
• Pain subsided without specific diagnosis (n80)
  (46.2)

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Results
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Results

• Sensitivity 100
• Specificity 97
• Positive predictive value 95
• Negative predictive value 100
• Time savings are approximately 1 hour

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Images
Inflamed appendix
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Diverticulitis

• Diverticulitis

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Images
Cholecystitis
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Images
Pyelonephritis
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Limitations

• Some 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 pain
• Acute appendicitis may have resolved with
  non-surgical treatment

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Conclusions

• IV 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 improved