Cerebral blood volume measurement by Tc-99m-DTPA-HSA SPECT was performed in a patient with subacute cerebral infarction to evaluate compensatory vasodilatation. Additional delayed imaging revealed focal increased radioactivity that was not found on the early images, indicating leakage of radioactive agents due to blood-brain barrier breakdown. Delayed SPECT may be helpful to detect areas unsuitable for estimating regional blood volume.