Figure 1.

Brain perfusion SPECT of dental pain patients receiving analgesia (top row) vs. placebo (bottom row). (A) Asymmetric thalamic activity, more on the right (thin arrow). Post IV ketorolac, the post-interventional scan (B) of the same patient exhibits a slight “switch” in thalamic asymmetry, with mildly greater perfusion on the left (thin arrow). Noted also decreased perfusion in the anterior cingulate region with pain relief [thick arrows in (A) and (B)]. (C) Scan from another patient demonstrating mild asymmetric increased activity in the left thalamus (thin arrow). (D) Same patient with worsening pain after receiving IV placebo, the scan demonstrates more asymmetrically increased perfusion in the left thalamus (thin arrow). Not also increased perfusion in the anterior cingulate cortex compared to (C) (thick arrows). [Images by Newberg et al. (58), reproduced here with permission].