Tc99m HM-PAO single photon emission computed tomography in temporal lobe epilepsy

Area of Science:

• Neurology
• Nuclear Medicine

Background:

• Temporal lobe epilepsy (TLE) is a common neurological disorder.
• Accurate lateralization of epileptic foci is crucial for surgical planning.
• Computed transmission tomography (CT) is often normal in TLE patients.

Purpose of the Study:

• To evaluate the utility of single photon emission computed tomography (SPECT) in detecting regional cerebral blood flow abnormalities in patients with TLE and normal CT.
• To investigate the prevalence and persistence of interictal hyperperfusion in TLE.

Main Methods:

• 40 patients with TLE and normal CT underwent SPECT.
• Regional cerebral blood flow was assessed using SPECT.
• Repeat SPECT was performed in a subset of patients to assess persistence of findings.
• SPECT findings were correlated with clinical parameters and electroencephalography (EEG) data.

Main Results:

• Abnormalities in regional cerebral blood flow were detected in 26/40 patients.
• Findings included focal hypoperfusion (14 patients), focal hyperperfusion (6 patients), and combined abnormalities (6 patients).
• Bilateral abnormalities were observed in 4 patients.
• Interictal hyperperfusion persisted in 5/12 patients upon repeat SPECT.
• No significant correlations were found between SPECT findings and clinical parameters.
• Good agreement was observed between SPECT and EEG when both lateralized the epileptic focus.

Conclusions:

• HMPAO SPECT is a useful tool for detecting lateralizing abnormalities in temporal lobe epilepsy.
• Interictal hyperperfusion may be more prevalent and persistent in TLE than previously reported.
• SPECT findings in TLE may not correlate with clinical parameters or seizure frequency.