## **Core Concept**
Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) characterized by chronic inflammation and ulceration of the colonic mucosa. Early radiological detection is crucial for diagnosis and management. The first radiological sign often reflects subtle changes in the bowel wall or mucosa.

## **Why the Correct Answer is Right**
The correct answer, **. Loss of haustrations**, is considered an early radiological sign of ulcerative colitis. In the early stages of UC, the inflammation leads to edema and spasm of the bowel wall, which can cause loss of the normal haustral folds. This occurs before more severe complications like ulcers or strictures develop. The haustrations are a normal feature of the colon due to the arrangement of the taenia coli, and their loss indicates a pathological process affecting the colonic wall.

## **Why Each Wrong Option is Incorrect**
- **Option A: . Picket fence appearance** - This is more characteristic of Crohn's disease, another form of IBD, where deep longitudinal and transverse ulcers create a "picket fence" or "cobblestone" appearance on barium studies.
- **Option B: . Mucosal granularity** - While mucosal granularity can be an early sign of ulcerative colitis due to fine, superficial erosions and edema giving a textured appearance, it is often considered alongside loss of haustrations as an early change but is not the most specific answer provided here.
- **Option D: . Pseudopolyps** - These are a feature of long-standing ulcerative colitis, representing areas of regenerating mucosa amidst areas of ulceration and are not an early radiological sign.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that ulcerative colitis typically starts in the rectum and extends proximally in a continuous fashion, which can help differentiate it from Crohn's disease. Early recognition of radiological signs like loss of haustrations can facilitate diagnosis and intervention.

## **Correct Answer: B. Loss of haustrations**