What substance is NOT used in a venogram?

In a venogram, a medical imaging technique used to visualize veins, contrast material is introduced into the veins to enhance the visibility of the blood vessels under X-ray imaging. This allows healthcare professionals to detect abnormalities such as blood clots or other vascular issues.

Radiographs, or X-rays, are essential for capturing the images of the veins once the contrast material has been administered. A catheter is also utilized during the procedure to deliver the contrast material directly into the venous system, ensuring that the veins are adequately filled for optimal imaging.

In contrast, an electrolyte solution is not involved in the venogram process. Electrolyte solutions are typically used in different medical contexts, such as hydration or electrolyte balance, but they do not serve any purpose in the visualization of veins during a venogram. Thus, this substance is not used in the procedure, making it the correct answer.