All are the characteristics of raised ICT on a plain radiology except:
**Core Concept**
Raised intracranial pressure (ICT) is a critical clinical condition that can lead to various radiological findings on a plain radiograph of the skull. The underlying principle is that increased pressure within the cranial vault can cause several changes in the bony structures, including the sutures and the skull bones.
**Why the Correct Answer is Right**
The correct answer is related to the changes observed in the cranial vault due to raised ICT. When intracranial pressure increases, it can cause the cranial sutures to become widened, particularly the sutures of the anterior cranial fossa. This is due to the increased pressure exerted on the sutures, causing them to separate and widen. Additionally, the skull bones may become thinned or even eroded due to the increased pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** Widening of the cranial sutures is a characteristic of raised ICT, so this option is incorrect.
**Option B:** The "tram-track" appearance is a characteristic of raised ICT, which is caused by the widening of the cranial sutures. This option is incorrect because it is a characteristic of raised ICT.
**Option C:** The "empty sella" sign is a characteristic of raised ICT, which is caused by the herniation of the cerebellar tonsils through the foramen magnum. This option is incorrect because it is a characteristic of raised ICT.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that raised ICT can cause various radiological findings, including widening of the cranial sutures, thinning of the skull bones, and the "empty sella" sign. These findings can be subtle and may require careful interpretation to diagnose raised ICT.
**Correct Answer:** D.