Single photon emission computed tomography (SPECT) (contd)
The normal scan - HMPAO (10 mm resolution) The tomogram is examined in conjunction with structural imaging (CT or MRI) to aid interpretation.
- Assessment of blood flow changes in DEMENTIA
Blood flow is generally reduced, especially in temporal and parietal lobes
- Evaluation of patients with intractable EPILEPSY of temporal lobe origin
Scan of temporal lobe showing symmetrical pattern of blood flow more prominent in grey matter
Patient with temporal lobe epilepsy
An interictal scan shows reduced flow throughout the temporal lobe
An ictal scan (i.e. HMPAO injectcd during the seizure) shows a marked hyperperfusion of the temporal lobe
The plane of scan lies in the same axis as the temporal lobe
- Detection of early ischaemia in OCCLUSIVE and HAEMORRHAGIC CEREBROVASCULAR DISEASE
Absence of blood flow corresponds with area of infarction and tissue loss seen on structural imaging.
Such findings aid localisation of the epileptic focus and selection of patients for surgical treatment.
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