Is computed tomography (CT) with or without contrast indicated for diagnosing appendicitis?

From the Guidelines

For suspected appendicitis, CT scanning with intravenous contrast is generally preferred over non-contrast CT, as it provides better visualization of the appendix and surrounding inflammation, allowing for more accurate diagnosis and detection of complications 1. When it comes to diagnosing appendicitis, the goal is to minimize morbidity, mortality, and improve quality of life by accurately diagnosing the condition and initiating prompt treatment.

• The use of intravenous contrast in CT scans for appendicitis has been shown to have high diagnostic accuracy, with sensitivity and specificity ranging from 94-98% and 95-97%, respectively 1.
• Non-contrast CT may be appropriate in patients with contraindications to contrast media, such as those with severe contrast allergies or significant renal impairment 1.
• The radiation dose should be optimized using low-dose techniques when possible, especially in younger patients.
• Oral contrast is generally not necessary and may delay diagnosis, though rectal contrast can sometimes be helpful in specific cases 1.
• CT scanning for appendicitis has significantly reduced negative appendectomy rates and improved patient outcomes by enabling prompt, accurate diagnosis 1.
• The most recent and highest quality study, published in 2024, recommends the use of CT with intravenous contrast for suspected appendicitis, as it provides the best diagnostic accuracy and allows for the detection of complications such as perforation or abscess formation 1.

From the Research

CT for Appendicitis with or without Contrast

• The use of contrast in CT scans for appendicitis has been studied in several research papers 2, 3, 4, 5, 6.
• A study published in 2012 found that CT scans with intravenous contrast alone have comparable diagnostic performance to CT scans with both intravenous and oral contrast for appendicitis in adults 2.
• Another study published in 2009 found that the use of oral and IV contrast media does not significantly impact the diagnostic correctness of MDCT for suspected acute appendicitis in adults 3.
• A retrospective review published in 2008 found that CT scans without rectal contrast are effective for the diagnosis of acute appendicitis, with a sensitivity of 90%, specificity of 98%, and accuracy of 94% 4.
• A study published in 2006 found that CT scans with IV contrast material are sensitive and specific for the confirmation or exclusion of acute appendicitis, with a sensitivity of 100% and specificity of 97% 5.
• A retrospective cohort study published in 2018 found that oral contrast does not improve CT diagnosis of acute appendicitis in children, and that CT turnaround time is significantly faster without oral contrast 6.

Key Findings

• CT scans with intravenous contrast alone are sufficient for the diagnosis of appendicitis in adults 2.
• The use of oral contrast does not significantly impact the diagnostic correctness of MDCT for suspected acute appendicitis in adults 3.
• CT scans without rectal contrast are effective for the diagnosis of acute appendicitis 4.
• CT scans with IV contrast material are sensitive and specific for the confirmation or exclusion of acute appendicitis 5.
• Oral contrast does not improve CT diagnosis of acute appendicitis in children and increases wait time 6.