Changes in regional cerebral blood flow in the thalamus after electroconvulsive therapy for patients with central post-stroke pain

The aim of the present study was to examine whether changes in regional cerebral blood flow (rCBF) induced by electroconvulsive therapy (ECT) in the thalamus are related to the efficacy of ECT. Two chronic pain patients with central post-stroke pain (53 and 58 years old), who had failed to respond to standard pain treatments, received a series of ECT treatments. To investigate the possible mechanisms of the analgesic effect of ECT on chronic central post-stroke pain, we measured changes in the rCBF of the thalamus using technetium-99m ethyl cysteinate dimer single photon emission computed tomography (99mTc ECD SPECT), before and after ECT. One patient responded to ECT treatment (response defined as a reduction in pain of at least 60% on the visual analogue scale), but the other patient had minimal clinical response to ECT. 99mTc ECD SPECT showed that the mean contralateral thalamus-to-cerebellum ratio increased 9.5% after ECT, compared to the ratio before ECT in the responder, but remained unchanged in the non-responder. The results from the SPECT suggest that normalization of of the balance of rCBF in the thalamus may be related to the analgesic efficacy of the ECT on central post-stroke pain.