SPECT AND PLANAR BRAIN IMAGING IN CRACK ABUSE - IODINE-123-IODOAMPHETAMINE UPTAKE AND LOCALIZATION

The uptake, distribution, and clearance properties of I-123-IMP in the brain were evaluated in controls and asymptomatic crack users to inve stigate cerebral blood flow alterations in crack abuse. Serial dynamic planar images of the brain (0-25 min), SPECT of the brain (0.5 hr and 4 hr) and whole-body scans (75 min) were obtained in 21 crack abusers and 21 control subjects. Major observations include: (a) foci of abno rmally reduced I-123-IMP activity mainly in the frontal and parieto-oc cipital cortex or marked irregularities in the uptake of I-123-IMP thr oughout the cerebral cortex consistent with moderate to severe disrupt ion in regional cerebral blood flow were observed on the 0.5 hr SPECT images of 16/21 asymptomatic crack users; (b) no correlation could be demonstrated between the incidence or severity of SPECT perfusion abno rmality with the frequency, amount or length of time of crack use; (c) focal perfusion defects observed in 6/21 crack users on the 0.5-hr SP ECT images partially or completely filled-in on delayed SPECT at 4 hr in four of six subjects; (d) the rate of cerebral uptake of I-123-IMP in crack users averaged 23% less than observed in control subjects ove r the first 25 min after tracer administration; and (e) I-123-IMP acti vity reaching the brain of cigarette smoking control subjects (n = 14) at 25 min after injection averaged 42.5% less than in nonsmoking cont rols (n = 7). Quantitative measurements of the uptake and distribution properties of I-123-IMP in the brain proved to be an objective, sensi tive and useful measure of regional cerebral blood flow in crack abuse .