Table 2 Considerations for imaging modality to assess for cerebral hypoperfusion and cerebrovascular reserve
| Â | Advantages | Disadvantages |
|---|---|---|
SPECT/CT | Can be performed in supine and standing position to assess for orthostatic changes in cerebral perfusion Radiotracer can be administered during clinical events to differentiate hypoperfusion events with epileptic hyperperfused events | Greater effective dose of whole body radiation in comparison to MRI, PET or CT perfusion |
CT Perfusion | Fast scan times | High target organ radiation to the head Nephrotoxic effects of iodine based contrast |
Arterial Spin Labelling MRI | No radiation No contrast required | Low signal to noise ratio requiring prolonged scan times (high risk of movement artefact) Patient intolerance to MRI (claustrophobia, large body habitus) |
Contrast enhanced perfusion MRI | No radiation | Patient intolerance to MRI (claustrophobia, large body habitus) Gadolinium contrast risks |
PET | Gold standard cerebral blood flow quantitation | Short lived radiotracer requires on-site cyclotron Technically demanding |