Which kidney contrast enhancement phase occurs approximately 70-90 seconds after contrast administration?

The nephrographic phase is characterized by optimal contrast enhancement of the renal parenchyma and occurs approximately 70-90 seconds after the administration of iodinated contrast material. During this phase, the cortex and medulla of the kidneys are well visualized, making it an ideal time for assessing kidney morphology, detecting lesions, and evaluating renal function.

In this timeframe, the contrast material has had sufficient time to perfuse the kidneys and be absorbed by the renal tubules, providing a clear delineation of the renal anatomy and any pathological findings. This phase is particularly valuable for imaging conditions such as renal tumors, cysts, or infarcts, as it allows for the best visualization of the renal tissue and its vascularity.

In contrast, the corticomedullary phase occurs earlier, typically within the first 30-40 seconds post-contrast injection. The excretory phase happens later, usually around 3 to 15 minutes after contrast administration, when the contrast is primarily in the collecting systems of the kidneys. The delayed phase, occurring after the excretory phase, allows for viewing structures outside of the kidneys and further assesses any abnormalities, but it does not provide the same level of detail of the renal parenchyma as the