Diffusion-weighted imaging (DWI) is best described as:

Diffusion-weighted imaging (DWI) is best described as:

• A. Maps movement of water molecules at the microscopic level to reveal damaged brain tissue
• B. Produces inverse imaging using diffusion with ADC
• C. Detects hemorrhage exclusively
• D. Not useful for acute stroke

Answer: (A)

Diffusion-weighted imaging probes how water molecules move within tissue. In a healthy brain, water diffuses relatively freely, but during an acute stroke energy failure causes cells to swell (cytotoxic edema), shrinking the extracellular space and restricting water diffusion. This restricted diffusion stands out on DWI as bright signal in the affected area, with the corresponding ADC map showing decreased diffusion. Because diffusion restriction appears early in ischemia, DWI is highly sensitive for acute stroke and can reveal changes within minutes, guiding urgent treatment. The idea of “inverse imaging using diffusion with ADC” isn’t how DWI is described clinically; ADC maps quantify diffusion and are derived from diffusion-weighted data, but there isn’t an official concept of inverse imaging here. Hemorrhage detection isn’t exclusive to DWI—the best sequences for hemorrhage are other MRI sequences like T2* or SWI—so DWI’s primary strength isn’t hemorrhage detection. And DWI is indeed very useful for acute stroke, not not useful.

Diffusion-weighted imaging probes how water molecules move within tissue. In a healthy brain, water diffuses relatively freely, but during an acute stroke energy failure causes cells to swell (cytotoxic edema), shrinking the extracellular space and restricting water diffusion. This restricted diffusion stands out on DWI as bright signal in the affected area, with the corresponding ADC map showing decreased diffusion. Because diffusion restriction appears early in ischemia, DWI is highly sensitive for acute stroke and can reveal changes within minutes, guiding urgent treatment.

The idea of “inverse imaging using diffusion with ADC” isn’t how DWI is described clinically; ADC maps quantify diffusion and are derived from diffusion-weighted data, but there isn’t an official concept of inverse imaging here. Hemorrhage detection isn’t exclusive to DWI—the best sequences for hemorrhage are other MRI sequences like T2* or SWI—so DWI’s primary strength isn’t hemorrhage detection. And DWI is indeed very useful for acute stroke, not not useful.