Which imaging study of the urinary system is considered a structural study rather than a functional study?

A retrograde pyelogram is considered a structural study because it involves administering contrast material directly into the urinary system through a catheter inserted into the ureters, often to visualize the anatomy of the renal pelvis, ureters, and bladder. This procedure allows for detailed imaging of the structural characteristics and any potential abnormalities present in these areas, such as tumors, strictures, or stones.

In contrast, functional studies focus on the physiological processes of the urinary system, such as how well the kidneys are filtering blood or how effectively urine is being produced and excreted. Other imaging modalities like ultrasound, CT scans, and X-rays can also provide information about the structure of the urinary system; however, they may incorporate functional elements by assessing things like blood flow or kidney size in relation to function.

Each imaging study serves specific purposes, and recognizing the distinction between functional and structural studies is crucial in determining the appropriate approach for diagnosis and treatment.