**Question:** Diffuse axonal injury is best detected in

A. Diffusion tensor imaging (DTI)
B. Computed tomography (CT)
C. Magnetic resonance imaging (MRI)
D. Plain skull radiographs

**Correct Answer: C. Magnetic resonance imaging (MRI)**

**Core Concept:**
Diffuse axonal injury (DAI) is a type of traumatic brain injury (TBI) caused by shearing forces, which result in damage to the axons of neurons. DAI is characterized by the disruption of white matter connections in the brain, leading to neurological deficits. In the context of neuroimaging, various techniques are used to detect this injury.

**Why the Correct Answer is Right:**
MRI is the most sensitive method for detecting diffuse axonal injury due to its superior soft tissue contrast and multiplanar imaging capabilities. Diffusion tensor imaging (DTI) is a specific MRI technique that evaluates the integrity of white matter tracts, which can help identify DAI. MRI is crucial for assessing the extent of brain injury and guiding treatment decisions.

**Why Each Wrong Option is Incorrect:**

A. **Diffusion tensor imaging (DTI)**: Although DTI is a valuable MRI technique for assessing white matter integrity, it is not the most sensitive method for detecting diffuse axonal injury.

B. **Computed tomography (CT)**: CT scans are less sensitive than MRI in detecting DAI due to their inability to visualize soft tissues and lack of multiplanar imaging capabilities.

C. **Magnetic resonance angiography (MRA)**: MRA is a technique used to visualize blood vessels and is not suitable for detecting diffuse axonal injury.

D. **Plain skull radiographs**: Plain skull radiographs are not suitable for detecting diffuse axonal injury as they only visualize bones and not the soft tissues of the brain.

**Clinical Pearl:**
MRI is essential in the evaluation of patients with suspected TBI as it offers detailed information about the brain's structural integrity and can help guide appropriate treatment. When assessing a patient with possible diffuse axonal injury, it is crucial to use the most sensitive imaging modality available, which is MRI in this case.