Investigation of choice in gall bladder stone is:
**Core Concept**
The investigation of choice for gallbladder stones involves imaging techniques that provide detailed visualization of the gallbladder and its contents. This requires a modality that can accurately detect gallstones, assess their size, and evaluate the gallbladder's morphology.
**Why the Correct Answer is Right**
The correct answer is **C. Ultrasonography** because it is a non-invasive, cost-effective, and highly sensitive imaging modality for detecting gallstones. Ultrasonography uses high-frequency sound waves to create images of the gallbladder, and it can identify gallstones, gallbladder inflammation, and other abnormalities. This modality is particularly useful because it does not expose the patient to ionizing radiation and can be performed quickly.
**Why Each Wrong Option is Incorrect**
**Option A:** Magnetic Resonance Cholangiopancreatography (MRCP) is not the investigation of choice for gallbladder stones because while it provides excellent visualization of the bile ducts, it is not as sensitive for detecting small gallstones. MRCP is often used as a follow-up imaging modality after an initial ultrasound.
**Option B:** Computed Tomography (CT) scan is not the investigation of choice for gallbladder stones because while it can detect gallstones, it exposes the patient to ionizing radiation and is more expensive than ultrasonography. CT scans are often used in emergency settings or when other imaging modalities are inconclusive.
**Option D:** Endoscopic Retrograde Cholangiopancreatography (ERCP) is not the investigation of choice for gallbladder stones because it is an invasive procedure that is typically reserved for therapeutic interventions, such as removing stones or dilating bile ducts. ERCP is not used for initial diagnosis or screening.
**Clinical Pearl / High-Yield Fact**
Ultrasonography is the preferred imaging modality for gallbladder stones because it is non-invasive, cost-effective, and highly sensitive. It is essential to remember that ultrasonography should be performed by an experienced sonographer or radiologist to ensure accurate results.
**Correct Answer:** C. Ultrasonography