In which medical imaging technique is a contrast agent typically utilized?

A contrast agent is commonly used in various medical imaging techniques to enhance the visibility of internal structures, making it easier for healthcare professionals to diagnose conditions.

In X-rays, contrast agents can help delineate different tissues or structures in the body. For instance, barium sulfate is often used in gastrointestinal studies to highlight the esophagus, stomach, and intestines, providing clearer images.

In CT scans, contrast agents such as iodine are frequently administered to improve the clarity of images. These agents help distinguish blood vessels and various types of tissues, allowing for improved diagnosis of conditions like tumors or internal bleeding.

MRI also utilizes contrast agents, typically gadolinium-based, to enhance the contrast of images. This helps in differentiating between normal and abnormal tissues, particularly in examinations of the brain and spine.

Given that contrast agents are effectively used across all these imaging modalities, the correct answer encompasses all of them, highlighting the integral role of contrast in improving image quality and diagnostic accuracy in medical imaging.