**Question:** Characteristic CT finding in acute SDH is-

A. Peri-tumoral edema
B. Mottled appearance
C. Hemosiderin deposition
D. Mixed density with air-fluid level

**Core Concept:** Subdural Hemorrhage (SDH) is a type of traumatic brain injury caused by bleeding between the skull and the brain. CT (Computed Tomography) imaging is a common method to diagnose SDH.

**Why the Correct Answer is Right:** D. Mottled appearance refers to the characteristic CT finding in acute subdural hemorrhage. In this condition, there is bleeding between the dura mater (the outer layer of the brain) and the arachnoid mater (the middle layer of the brain). The bleeding causes a mottled appearance due to varying degrees of hyperdense (high-density) and isodense (normal density) regions.

**Why Each Wrong Option is Incorrect:**

A. Peri-tumoral edema (edema around a tumor) is not a characteristic finding in acute SDH.
B. Mottled appearance is a correct answer but is not specific to acute SDH. Other conditions like epidural hemorrhage or subarachnoid hemorrhage can also present with mottled appearance on CT scans.
C. Hemosiderin deposition occurs in chronic subdural hemorrhage, where the iron from the broken red blood cells deposits in the brain tissue, leading to the characteristic sign of "black hole" or "iron spot" on imaging studies. This is not relevant for acute SDH.

**Clinical Pearl:** The characteristic finding of mottled appearance on CT scan in acute subdural hemorrhage aids in diagnosis and helps differentiate it from other neurological conditions. Prompt management is essential to prevent complications like cerebral herniation and neurological deterioration.