**Core Concept:** Extradural hemorrhage (EDH) is a type of traumatic brain injury caused by bleeding between the skull and the dura mater, the outer layer of the brain. Non-contrast computed tomography (NCCT) of the head is a diagnostic imaging modality used to detect EDH.

**Why the Correct Answer is Right:** Extradural hemorrhage in NCCT Head is typically seen as a hyperdense lesion. The term "hyperdense" refers to increased density on CT scans, which represents increased concentration of iodine from the contrast used in the CT scan. In the context of EDH, a hyperdense lesion indicates the presence of blood between the skull and dura mater.

**Why Each Wrong Option is Incorrect:**

A. Hypodense: This term refers to decreased density on CT scans, representing decreased concentration of iodine. Hypodense lesions are not characteristic of EDH and would indicate other causes like low-density hemorrhage, cerebral edema, or low-density substances within the subarachnoid space.

B. Equivalent density: A lesion with equivalent density would not differ significantly from the surrounding brain tissue in terms of iodine concentration, making it less likely to represent a hyperdense extradural hemorrhage.

C. Equipotent substance: This term refers to a substance with similar density to the brain tissue, which is also incorrect for the context of EDH in NCCT Head.

D. Increased density: This term is similar to hyperdense, but it specifically mentions increased density. However, increased density alone does not specifically confirm EDH; other causes like subdural hematoma or cerebral edema can also result in increased density on CT scans.

**Clinical Pearl:** Hyperdense extradural hemorrhage on NCCT head is a crucial clue for the diagnosis of EDH. However, the presence of a hyperdense lesion does not definitively confirm the diagnosis; a thorough clinical evaluation and correlation with other imaging modalities like CT angiography is essential for accurate diagnosis and management of the patient.