Which of the following is not a feature of renovascular hypertension on IVU?
**Core Concept**
Renovascular hypertension is a condition where the narrowing or blockage of the renal arteries leads to high blood pressure. Intravenous urography (IVU), also known as intravenous pyelography (IVP), is a radiological examination that visualizes the urinary system.
**Why the Correct Answer is Right**
In renovascular hypertension, the affected kidney may show delayed function or atrophy due to ischemia. However, one key feature of renovascular hypertension on IVU is the presence of a "string sign" or "reninoma sign," which is a narrow, beaded, or string-like appearance of the affected renal artery. This is due to the stenosis or narrowing of the renal artery. Another feature is the presence of delayed nephrogram or delayed excretion of the contrast medium, indicating impaired renal function. Additionally, the affected kidney may show a smaller size or atrophy.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a delayed nephrogram is indeed a feature of renovascular hypertension on IVU, indicating impaired renal function.
**Option B:** This option is incorrect because a string sign or reninoma sign is a characteristic feature of renovascular hypertension on IVU, indicating stenosis or narrowing of the renal artery.
**Option C:** This option is incorrect because atrophy or delayed function of the affected kidney is a common feature of renovascular hypertension on IVU, indicating ischemia.
**Clinical Pearl / High-Yield Fact**
It is essential to recognize the string sign or reninoma sign on IVU as a key feature of renovascular hypertension, which may prompt further investigation, such as angiography or CT angiography, to confirm the diagnosis.
**Correct Answer: D.**