When is a computed tomography (CT) scan with intravenous (IV) contrast indicated?

From the Guidelines

A computed tomography (CT) scan with intravenous (IV) contrast is indicated in various clinical scenarios, including detecting vascular abnormalities, evaluating tumors and masses, identifying infections or abscesses, and assessing organ function, as evidenced by the most recent and highest quality study 1. When considering the use of IV contrast in CT scans, it is essential to weigh the benefits against the potential risks, such as contrast-related complications, radiation exposure, and the dangers of transporting a patient away from the resuscitation environment into the CT scanner. Some specific indications for CT scans with IV contrast include:

• Detecting vascular abnormalities like aneurysms or arterial dissections
• Evaluating tumors and masses to assess blood supply and enhancement patterns
• Identifying infections or abscesses
• Evaluating organ function in the liver, kidneys, or pancreas
• Assessing for pulmonary embolism
• Detecting stroke in brain imaging According to the American College of Radiology (ACR) Appropriateness Criteria, CT scans with IV contrast are usually appropriate in various clinical scenarios, including nonlocalized abdominal pain and fever, postoperative patients with suspected abscesses or leaks, and patients with abdominal pain and neutropenia 1. In the setting of postpartum hemorrhage, CT scans with IV contrast can help determine whether active ongoing hemorrhage is present, localize the bleeding, and identify the source 1. It is crucial to screen patients for kidney function, history of contrast allergies, and conditions like metformin use or multiple myeloma before administering IV contrast, and to ensure they are well-hydrated before the procedure 1.

From the FDA Drug Label

Because unenhanced scanning may provide adequate diagnostic information in the individual patient, the decision to employ contrast enhancement, which may be associated with risk and increased radiation exposure, should be based upon a careful evaluation of clinical, other radiological, and unenhanced CT findings. Utilization of a continuous scanning technique (ie, dynamic CT scanning) may improve enhancement and diagnostic assessment of tumor and other lesions such as abscess, occasionally revealing unsuspected or more extensive disease For example, a cyst may be distinguished from a vascularized solid lesion when precontrast and enhanced scans are compared; the nonperfused mass shows unchanged x-ray absorption (CT number) A vascularized lesion is characterized by an increase in CT number in the few minutes after a bolus of intravascular contrast agent; it may be malignant, benign, or normal tissue, but would probably not be a cyst, hematoma, or other nonvascular lesion

A computed tomography (CT) scan with intravenous (IV) contrast is indicated when:

• Unenhanced scanning does not provide sufficient diagnostic information
• Clinical evaluation suggests the need for contrast enhancement to assess lesions such as tumors or abscesses
• Diagnostic assessment of vascularized lesions is required to distinguish them from non-vascular lesions like cysts or hematomas 2

From the Research

Indications for CT Scan with IV Contrast

• A computed tomography (CT) scan with intravenous (IV) contrast is indicated in various clinical scenarios, including acute abdominal pain in adults 3.
• The use of IV contrast media in CT examinations is often valuable in improving diagnostic accuracy, particularly in emergency departments (ED) 4.
• CT scans with IV contrast are commonly used in the evaluation of blunt trauma patients, with a low incidence of contrast-induced nephropathy (CIN) 5.

Specific Clinical Scenarios

• In patients with urgent clinical symptoms, administering IV contrast for CT abdomen and pelvis improves detection of urgent and clinically important non-urgent pathology compared to non-contrast CT 6.
• IV contrast-enhanced CT scans are also useful in characterizing both urgent and non-urgent findings in patients with acute abdomen and impaired renal function 3.
• The use of central venous catheters for IV contrast injection for CT examinations may be considered in patients with difficult peripheral access 7.

Guidelines and Recommendations

• Updated guidelines for IV contrast use in CT and MRI scans recommend more liberal use of IV contrast media, with fewer precautions than prior guidelines 4.
• Adherence to American College of Radiology (ACR) appropriateness criteria for IV contrast administration is associated with increased detection of urgent pathology on the first CT scan 6.