The time delay between in vivo imaging and postmortem data poses a caveat on “no link” findings

Abstract

I read with interest the article by Honkanen and colleagues on the question of correlation between striatal dopaminergic innervation and dopamine transporter (DAT) imaging as assessed by putamen tyrosine hydroxylase–positive axon counts and DAT single-photon emission computed tomography (SPECT). In their 14 patients with neuropathologically confirmed Parkinson’s disease or atypical parkinsonism, specific binding ratios (SBRs) from SPECT did not correlate with the total putamen tyrosine hydroxylase-positive fiber counts. This is very surprising given that DATs are densely present on dopaminergic axons with varicosities, and nearly all striatal