For evolving infarcts, what happens to ADC values?

For evolving infarcts, what happens to ADC values?

• A. Increases and appears brighter
• B. Decreases and appears darker
• C. Stays the same
• D. Not related to infarct

Answer: (B)

In evolving infarcts, diffusion becomes restricted because cells swell from cytotoxic edema as energy failure impairs ion pumps. This intracellular swelling limits water movement, so the apparent diffusion coefficient (ADC) decreases. On ADC maps, this restricted diffusion shows up as darker signal, reflecting lower ADC values. This acute restriction is a hallmark of early ischemia. Over time, ADC can pseudonormalize and later increase as vasogenic edema and tissue breakdown occur, but the initial evolving phase is characterized by reduced ADC.

In evolving infarcts, diffusion becomes restricted because cells swell from cytotoxic edema as energy failure impairs ion pumps. This intracellular swelling limits water movement, so the apparent diffusion coefficient (ADC) decreases. On ADC maps, this restricted diffusion shows up as darker signal, reflecting lower ADC values. This acute restriction is a hallmark of early ischemia. Over time, ADC can pseudonormalize and later increase as vasogenic edema and tissue breakdown occur, but the initial evolving phase is characterized by reduced ADC.