Contrastenhanced

Contrast-enhanced refers to imaging techniques that use a contrast agent to improve the visibility of internal structures. By changing the way tissues or vessels appear on an image, a contrast-enhanced study can help delineate anatomy, detect lesions, and assess perfusion or vascularity.

Common imaging modalities employing contrast include computed tomography (CT) with iodinated contrast, magnetic resonance imaging (MRI) with gadolinium-based agents, and ultrasound with microbubble contrast. The agents work by accumulating in certain tissues, altering signal intensity or attenuation, and sometimes remaining within vascular or extracellular compartments.

Applications include tumor detection and characterization, infection or inflammatory processes, evaluation of blood vessels and blood flow, and assessment of organ perfusion and function. Dynamic contrast-enhanced protocols capture arterial and venous phases to study vascularity and tissue perfusion.

Safety and limitations: Contrast agents can cause allergic reactions, and iodinated agents carry a risk of contrast-induced nephropathy, especially in patients with preexisting kidney disease. Some gadolinium-based agents have been associated with nephrogenic systemic fibrosis in severe kidney failure. Providers screen patients for risk factors, use the lowest effective dose, and choose the most appropriate agent. Renal function assessment and history of previous reactions are common pre-imaging steps. Some patients may not be candidates for contrast.

Alternatives and considerations: non-contrast imaging sequences or other modalities may be used if contrast is unsuitable. Artifacts, cost, and availability can limit use. The term contrast-enhanced can also apply outside radiology, referring generally to the use of contrast dyes in various imaging or visualization contexts.