Anterior radionuclide angiogram of the skull.
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View second image(br). Immediate static images of the skull.
Full history/Diagnosis is available below
Immediate static images demonstrate overlying soft tissue activity, but no dural sinus activity.
This test may be used as an ancillary procedure in the determination of brain death. The exact standards for determination of brain death vary depending on state and hospital policy, but typically no single test is used as the single diagnostic test to determine brain death.
The cerebral edema accomanying necrosis of brain tissues results in increased intracranial pressure, since the skull is a relatively closed cavity. When this pressure rises above arterial pressure, blood flow to the brain ceases.
Note that the brain stem and cerebellum is not well evaluated on this study, hence the diagnosis of "lack of effective cerebral perfusion". If desired, a brain perfusion agent such as Tc-99m HMPAO could be used to evaluate the entire brain; however the equivical increased utility of HMPAO in this setting likely does not warrent the additional expense.
Contrast this study to the normal brain perfusion study also located in this teaching file.
A tournequet placed around the scalp (just above the eyes) can decrease scalp blood flow, making the study easier to interpret.
Increased flow to the nasal region ("hot nose sign") is sometimes seen as an ancillary finding.
The interpretation of this study should read "No evidence of effective cerebral perfusion" rather than "brain death". This study does not evaluate the brainstem effectively, and lack of brainstem function (and other clinical criteria) are typically needed to diagnose brain death.
References and General Discussion of Brain Scintigraphy (Anatomic field:Skull and Contents, Category:Organ specific)
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