Figure 3. Parametric images of μ-opioid receptor availability from a representative heroin-dependent volunteer during daily maintenance on buprenorphine placebo (row 2 from the top, Bup 0), 2 mg (Bup 2), 16 mg (Bup 16), and 32 mg (Bup 32). Images are scaled so that binding in the occipital cortex, an area devoid of u-receptors, is equal to 1. Four transverse sections from superior (column 1) to inferior (column 4) and one sagittal section (column 5) are shown, which correspond to T1-weighted anatomical MRI images (row 1). The pseudocolor scale depicts DVR values from 1 to 4. Reproduced from reference 42: Greenwald MK, Johanson CE, Moody DE, et al. Effects of buprenorphine maintenance dose on mu-opioid receptor availability, plasma concentrations, and antagonist blockade in heroin-dependent volunteers. Group. BUP, buprenorphine; DVR, direct volume rendering; MRI, magnetic resonance imaging. Figure reproduced with permission from ref 42: Greenwald MK, Johanson CE, Moody DE, et al. Effects of buprenorphine maintenance dose on mu-opioid receptor availability, plasma concentrations, and antagonist blockade in heroin-dependent volunteers. Neuropsychopharmacology. 2003;28(11):2000-2009. © 2003 Nature Publishing Group.