What are the imaging modalities for diverticulitis (inflammation of the diverticula)?

From the Guidelines

Computed Tomography (CT) of the abdomen and pelvis is the preferred imaging modality for diagnosing diverticulitis, due to its high diagnostic accuracy and ability to identify complications. When a patient presents with suspected diverticulitis, a CT scan should be performed promptly to confirm the diagnosis and assess for complications, as it has a superior diagnostic accuracy of 98% 1. The CT will typically show colonic wall thickening, pericolic fat stranding, and diverticula, with possible complications such as abscess, perforation, or fistula formation.

Key Considerations

• IV contrast material is commonly used to improve the characterization and detection of subtle bowel wall abnormalities and complications of diverticulitis, but it is not necessary for the diagnosis of diverticulitis in most patients 1.
• Unenhanced CT is more accurate than clinical evaluation alone and can be used in patients with contraindication to IV contrast material 1.
• Radiation dose–reduced CT can be accurate for acute diverticulitis, with a similar sensitivity and specificity to “standard dose” contrast-enhanced CT 1.
• CT may also help predict which patients are likely to experience recurrent diverticulitis and thereby augment triage between surveillance and operative management 1.

Alternative Imaging Modalities

• Ultrasound may be used as an initial screening tool, particularly in young patients or pregnant women to avoid radiation exposure, but it is less sensitive and operator-dependent 1.
• Magnetic Resonance Imaging (MRI) serves as an alternative when CT is contraindicated, offering similar diagnostic accuracy without radiation 1.
• Plain radiographs have limited utility but may detect free air in cases of perforation.
• Colonoscopy is generally avoided during acute episodes due to the risk of perforation but is recommended 6-8 weeks after resolution to exclude malignancy, especially in patients over 50 years old or those with concerning features.

Clinical Decision Making

Early and appropriate imaging is crucial for guiding treatment decisions, including the need for antibiotics, percutaneous drainage, or surgical intervention. The choice of imaging modality should be based on the individual patient's circumstances, taking into account factors such as radiation exposure, contrast allergy, and availability of imaging modalities 1.

From the Research

Diverticulitis Imaging Options

• Computed Tomography (CT) is considered a valuable radiologic examination for diagnosing acute left colonic diverticulitis 2, 3
• CT has been shown to be superior to water-soluble contrast enema in terms of sensitivity (98% vs 92%) and evaluation of the severity of inflammation (26% vs 9%) 2, 3
• CT is useful in detecting severe infection, especially when an abscess is associated with the disease 2, 3

Comparison of Imaging Modalities

• A study comparing barium enema and CT found that CT was diagnostic in 41% of patients, while barium enema was correct in 77% of patients 4
• However, another study found that non-contrast CT was non-inferior to contrast-enhanced CT for the diagnosis of acute colonic diverticulitis 5
• Contrast-enhanced CT was associated with higher sensitivities for the presence of an abscess or perforation 5

Classification and Staging of Diverticulitis

• A radiological classification system has been created to guide the management of acute colonic diverticulitis, dividing it into complicated and uncomplicated cases 6
• The classification system takes into account the presence of microperforation, abscess, and peritoneum involvement, among other factors 6

Clinical Implications

• The choice of imaging modality may depend on the clinical presentation and suspected severity of the disease 2, 3, 4
• CT is a useful tool for evaluating the severity of diverticulitis and guiding treatment decisions 2, 3, 6