Magnetic resonance imaging signal hypointensity and iron content of putamen nuclei in elderly depressed patients

We previously introduced a semiquantitative scale for assessment of iron content of putamen nuclei as determined by magnetic resonance imaging (MRI) — the Signal Hypointensity in the Putamen (SHIP) scale. Such hypointensity may be related to putamen nuclei iron content, although this suggestion remains controversial, especially in the elderly. In the present study, we apply the SHIP scale to a sample of 68 elderly depressed patients (diagnosed with DSM-IV major depression using the Diagnostic Interview Schedule and clinical interview) and a group of 28 age-matched non-depressed control subjects. MRI scans were conducted on a single 1.5-T General Electric Signa system with axial acquisitions obtained parallel to the canthomeatal line. Technical parameters were as follows: (1) repetition time (TR)=500 ms and echo time (TE)=15 ms for T1-weighted images; (2) TR=2500 ms and TE=30 ms for proton-density-weighted images; and (3) TR=2500 ms and TE=80 ms for T2-weighted images. Among depressed patients, older age of depression onset and greater severity of depression were associated with increased putamen nuclei iron deposition. When depressed patients were compared with control subjects, the patient group demonstrated greater putamen nuclei iron, but the finding was significant only for the left hemisphere. Our findings support previous neuroimaging studies linking both changes in the basal ganglia and greater left-sided brain pathology to late-life depression.