Ziel/Aim:
The central noradrenaline (NA) system, which modulates cognitive processes such as
attention and working memory, has been implicated in the pathopyhisology of attention-deficit/hyperactivity
disorder (ADHD). In particular, the NA transporters (NAT) seems to play a key role
in ADHD as a treatment target for prescribed drugs such as methylphenidate and atomoxetine.
However, changes of NAT availability have not been described so far in adults with
ADHD.
Methodik/Methods:
To explore differences in NAT availability, PET and NAT-selective (S,S)-[11C]-O-methylreboxetine (MRB) were applied (mMR biograph, Siemens) in 18 patients with
ADHD (7 females, age 33.4 ± 8.5 years, 487.9 ± 8.3 MBq injected activity) and in 18
age- and sex-matched healthy controls (7 females, age 33.4 ± 7.4 years,468.6 ± 7.5
MBq). The regional distribution volume ratios (DVR) were calculated (VOI analysis)
based on the individual PET-MRI data coregistration and a multi-linear reference tissue
model with 2 contraints (MRTM2) and the occipital cortex serving as the reference
region.
Ergebnisse/Results:
We found lower DVR in patients with ADHD compared with healthy controls in several
brain regions, reaching statistical significance in the prefrontal brain regions (e.g.,
the right dorsolateral prefrontal cortex 1.04 ± 0.04 versus 1.07 ± 0.03, p = 0.01)
and the thalamus (right: 1.32 ± 0.09 versus 1.39 ± 0.09, p = 0.02) while most of the
other investigated brain regions showed a tendency towards lower DVR values in patients
compared with healthy controls.
Schlussfolgerungen/Conclusions:
These initial data are in line with an involvement of NAT in prefrontal cortex that
also includes thalamo-cortical circuitries. It is an ongoing study for further exploring
of how NA/NAT modulates neuronal (resting-state) activity simultaneously measured
by means of functional MR imaging and appropriate behavior as assessed by thorough
neuropsychological testing.
*Equal Contribution.
