**Question:** Investigation of choice in vesicoureteric reflux (VUR)?

**Core Concept:** Vesicoureteric reflux (VUR) is a condition where urine flows backwards from the bladder to the ureter and kidney, leading to an increased risk of urinary tract infections (UTIs) and long-term renal scarring.

**Why the Correct Answer is Right:** The correct answer, **Option C: Urography (IVU)**, is chosen because it provides comprehensive information about VUR and associated renal parenchymal damage. **Urography (IVU)**, also known as intravenous urography, is a radiological investigation that involves injecting a contrast medium into the bladder and observing its flow into the ureters and kidneys. This helps visualize the ureteric orifices, the ureteric calyces, and the renal parenchyma, providing essential information about VUR grades, the presence of associated renal scarring, and the overall renal function.

**Why Each Wrong Option is Incorrect:**

A. **Option A: Urine culture & sensitivity (C&S)**: While urine culture & sensitivity (C&S) is essential in diagnosing UTIs, it does not directly assess VUR. Urine culture helps identify the causative organism, while sensitivity testing determines the antibiotic sensitivity profile, enabling appropriate antibiotic therapy. However, neither provides information about VUR or renal parenchymal damage.

B. **Option B: Uroflowmetry**: Uroflowmetry measures the flow rate of urine during micturition. While this test is useful in evaluating lower urinary tract dysfunction, it does not assess VUR or provide information about renal parenchymal damage.

D. **Option D: Ultrasound**: Ultrasound is a non-invasive imaging tool used to evaluate renal parenchymal damage and is essential in detecting hydronephrosis. However, it does not directly assess VUR. Ultrasound is helpful in detecting renal scarring, but it cannot determine the severity of VUR.

**Clinical Pearl:** In cases of suspected VUR, a combined approach using various investigations is often necessary. This may include ultrasound, voiding cystourethrogram (VCUG), and sometimes urine culture & sensitivity, depending on the clinical scenario. A thorough clinical evaluation, including medical history, physical examination, and relevant laboratory tests, is essential in formulating a comprehensive diagnosis and treatment plan for patients with VUR.