1. Primary (main):

   1. Determine the diagnostic accuracy of CT KUB in differentiating between benign and suspicious renal cysts according to the Bosniak classification.

2. Secondary (subsidiary):

   1. Assess interobserver agreement in CT KUB interpretation among radiologists with varying levels of expertise.
   2. Identify limitations and pitfalls in the use of non-contrast CT KUB for characterizing renal cysts.

Renal cysts are among the most frequently encountered incidental findings(1) on abdominal imaging, particularly with the increasing use of cross-sectional imaging. Most simple cysts are benign and require no further evaluation.

However, complex cystic lesions pose a diagnostic challenge, necessitating accurate characterization to distinguish benign from malignant lesions.(2).

While CT KUB is highly effective for detecting urinary tract stones, there are several limitations and pitfalls we should be aware of as Limited Soft Tissue Assessment as without contrast, masses, infections, or vascular lesions may not be clearly visible also some tumors called isodensity tumors, have similar intensity values to the surrounding normal tissues.(3).

Segmentation of kidney tumors on CT KUB images adds challenges compared to contrast-enhanced CT (CECT) images, due to low contrast and lack of multiphase images. On CECT images, the kidney tumors have different intensity values compared to the normal tissues.(4).

Validating CT KUB's accuracy in assessing renal cysts could have significant implications for clinical decision making, especially in resource-limited or urgent care settings

Inclusion Criteria:

• Patients referred for CT KUB with detectable Renal cysts

Exclusion Criteria:

• 1-Patients with known renal tumors.
• 2-Inadequate imaging quality: CT KUB with severe motion/streak artifact or incomplete anatomical coverage preventing lesion assessment.

Patients with Renal Cysts referred to CT KUB for any indication