Figure 4:
Advantage of Tc-99m ECD and Tc-99m HMPAO versus Tc-99m DTPA. 17-month-old female s/p closed head injury.

A. Initial study performed with Tc-99m DTPA demonstrates arterial flow in the right hemisphere only. Superior sagittal sinus activity is typically seen on static DTPA images as this agent is not extracted by brain parenchyma and thus, cannot demonstrate metabolic function.

B. Seven hours later, HMPAO study demonstrates flow and metabolism on the right.

C. Twenty-four hours later, HMPAO study demonstrates no intracranial perfusion or metabolic function.

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