Is a CT (Computed Tomography) scan with or without intravenous (IV) contrast recommended for a patient presenting with right lower quadrant (RLQ) pain?

From the Guidelines

For patients presenting with right lower quadrant (RLQ) pain, a CT scan with intravenous (IV) contrast is generally recommended as the preferred imaging approach. The contrast-enhanced CT provides better visualization of inflammatory changes, vascular structures, and potential abscesses that may be present in conditions like appendicitis, which is a common cause of RLQ pain 1. The IV contrast helps differentiate between normal and abnormal tissue enhancement patterns, improving diagnostic accuracy. According to the American College of Radiology (ACR) Appropriateness Criteria, CT abdomen and pelvis with IV contrast is usually appropriate to evaluate for suspected appendicitis in patients with RLQ pain with fever and leukocytosis 1.

Some key points to consider when using CT scans for RLQ pain include:

• The use of IV contrast can help improve diagnostic accuracy, but it may not be necessary in all cases, such as in patients with contraindications to IV contrast 1.
• The typical contrast agent used is an iodinated contrast medium administered at a standard dose of 1-2 mL/kg.
• Prior to administering contrast, patients should be screened for allergies and kidney function should be assessed with recent creatinine levels 1.
• Patients should be well-hydrated before the procedure to reduce the risk of contrast-induced nephropathy.
• The enhanced visualization provided by contrast-enhanced CT allows for more accurate diagnosis of conditions like appendicitis, diverticulitis, inflammatory bowel disease, ovarian pathology, and urinary tract stones that may present with RLQ pain 1.

It's also important to note that alternative imaging modalities, such as MRI or ultrasound, may be used in certain situations, such as in pregnant patients or those with contraindications to CT scans 1. However, CT scans with IV contrast remain the preferred imaging approach for most patients with RLQ pain, due to their high diagnostic accuracy and ability to provide detailed images of the abdominal and pelvic structures 1.

From the Research

CT Scan for RLQ Pain

• A CT scan with or without intravenous (IV) contrast can be used to evaluate patients presenting with right lower quadrant (RLQ) pain, as it is a common cause of acute appendicitis (AA) and other conditions that can simulate the clinical presentation of AA 2.
• The use of CT with IV contrast has been shown to have high sensitivity and specificity for diagnosing acute appendicitis, especially in adult patients 3.
• However, the use of low-dose unenhanced CT has been found to be equal to standard-dose CT with IV contrast in detecting signs of acute appendicitis 4.

Alternative Imaging Modalities

• Ultrasound (US) is a useful imaging modality for evaluating RLQ pain, especially in pediatric patients and pregnant women, as it does not involve ionizing radiation 2, 3, 4.
• Magnetic Resonance Imaging (MRI) can also be used, particularly in pregnant women and young adults, as it does not involve ionizing radiation 3, 4.

Diagnostic Approach

• The diagnostic approach to evaluating patients with RLQ pain should consider the patient's age, gender, and clinical presentation, as well as the presence or absence of "classic" signs and symptoms of acute appendicitis 3.
• A systematic approach to evaluating RLQ pain can help identify a range of conditions that can cause this symptom, including bowel, mesentery/omentum/peritoneum, vasculature, urinary, and reproductive system disorders 2.