This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
'Stipple sign’ in transitional cell carcinoma of the renal collecting system is best demonstrated by 
Select and explain. 
A. Intravenous urography, B. Retrograde pyeloureterography, C. Radionuclide scan, D. Ultrasound scan
A: Intravenous urography
Answer: A: Intravenous urography 
Explanation: An intravenous pyelogram, also called an intravenous urogram, is a radiological procedure used to visualize abnormalities of the urinary system, including the kidneys, ureters, and bladder.