**Question:** Non visualization of the kidney is seen in all EXCEPT(Internet)

**Core Concept:** Kidney imaging and its normal appearances in various imaging modalities.

**Why the Correct Answer is Right:** Non-visualization of the kidney could be due to various reasons like inadequate contrast agent administration, patient positioning, or image acquisition issues. In this context, we are discussing the normal appearances of the kidney in different imaging modalities, excluding those that would not visualize the kidney.

**Why Each Wrong Option is Incorrect:**

A. Computed Tomography (CT) scan: Kidneys are typically visualized on CT scans due to their location and enhancement properties.

B. Ultrasonography (USG): Kidneys are visualized on USG due to their acoustic properties and position. The correct positioning during examination is crucial for optimal visualization.

C. Magnetic Resonance Imaging (MRI): Kidneys are usually visualized on MRI scans, especially T1 and T2-weighted sequences. MRI can provide detailed anatomical information and is helpful in assessing kidney size, shape, and parenchymal homogeneity.

D. Radionuclide scans: Kidneys are visualized on radionuclide scans (e.g., Technetium-99m dimercaptosuccinic acid (DMSA) scan) due to the uptake of the radiotracer by renal parenchyma.

**Clinical Pearl / High-Yield Fact:** Adequate patient positioning, appropriate contrast agent administration, and proper imaging technique are crucial for optimal kidney visualization in all imaging modalities mentioned above. Knowledge of normal kidney appearances on different imaging modalities is essential for accurate diagnosis and interpretation of imaging studies.

**Correct Answer:** None of the options A, B, and D are correct, as they all visualize the kidneys. However, option C (radionuclide scans) is the most likely scenario where kidneys might not be visualized due to the nature of the imaging modality.