Which imaging technique is considered the most sensitive and specific for demonstrating acute cerebral infarction?

MRI diffusion-weighted imaging is recognized as the most sensitive and specific imaging technique for identifying acute cerebral infarction. This method is particularly adept at detecting the early changes associated with ischemic strokes, often within minutes to hours after onset. The diffusion-weighted imaging (DWI) sequence highlights areas of restricted diffusion in the brain that correspond to cytotoxic edema, allowing clinicians to visualize the affected brain tissue with great precision.

In contrast, other imaging techniques, such as CT scans, while beneficial in specific circumstances, may not pick up acute infarctions in the very early stages, particularly in the first few hours post-stroke. X-ray imaging is largely limited in the evaluation of cerebral conditions due to its inability to provide adequate soft tissue contrast, which is crucial for visualizing brain changes. Ultrasound primarily serves in the evaluation of extracranial vessels and is not effective for direct visualization of cerebral infarctions. Therefore, the advantage of MRI diffusion-weighted imaging in early diagnosis of acute infarctions underscores its essential role in stroke management.