Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Eur J Nucl Med Mol Imaging. 2013 Apr;40(4):574-9. doi: 10.1007/s00259-012-2312-8. Epub 2012 Dec 14.
Dopamine D receptors (DRs) have two affinity states for endogenous dopamine, referred to as high-affinity state (D ), which has a high affinity for endogenous dopamine, and low-affinity state (D ). The density of D can be measured with (R)-2-CHO-N-n-propylnorapomorphine ([C]MNPA), while total density of D and D (DRs) can be measured with [C]raclopride using positron emission tomography (PET). Thus, the ratio of the binding potential (BP) of [C]MNPA to that of [C]raclopride ([C]MNPA/[C]raclopride) may reflect the proportion of the density of D to that of DRs. In the caudate and putamen, [C]MNPA/[C]raclopride reflects the proportion of the density of D to that of DRs. To evaluate the reliability of the PET paradigm with [C]MNPA and [C]raclopride, we investigated the test-retest reproducibility of non-displaceable BP (BP ) measured with [C]MNPA and of [C]MNPA/[C]raclopride in healthy humans.
Eleven healthy male volunteers underwent two sets of PET studies on separate days that each included [C]MNPA and [C]raclopride scans. BP values in the caudate and putamen were calculated. Test-retest reproducibility of BP of [C]MNPA and [C]MNPA/[C]raclopride was assessed by intra-subject variability (absolute variability) and test-retest reliability (intraclass correlation coefficient: ICC).
The absolute variability of [C]MNPA BP was 5.30 ± 3.96 % and 12.3 ± 7.95 % and the ICC values of [C]MNPA BP were 0.72 and 0.82 in the caudate and putamen, respectively. The absolute variability of [C]MNPA/[C]raclopride was 6.11 ± 3.68 % and 11.60 ± 5.70 % and the ICC values of [C]MNPA/[C]raclopride were 0.79 and 0.80 in the caudate and putamen, respectively.
In the present preliminary study, the test-retest reproducibility of BP of [C]MNPA and of [C]MNPA/[C]raclopride was reliable in the caudate and putamen.
多巴胺 D 受体（DR）对内源性多巴胺有两种亲和力状态，分别称为高亲和力状态（D）和低亲和力状态（D）。D 的密度可以用（R）-2-CHO-N-正丙基-诺啡烷（[C]MNPA）来测量，而 D 和 D 的总密度（DR）可以用正电子发射断层扫描（PET）用 [C]raclopride 来测量。因此，[C]MNPA 的结合潜能（BP）与 [C]raclopride 的 BP 之比（[C]MNPA/[C]raclopride）可能反映了 D 的密度与 DRs 密度的比例。在尾状核和壳核中，[C]MNPA/[C]raclopride 反映了 D 的密度与 DRs 密度的比例。为了评估使用 [C]MNPA 和 [C]raclopride 的 PET 范式的可靠性，我们研究了健康人类中使用 [C]MNPA 测量的非置换 BP（BP）和 [C]MNPA/[C]raclopride 的测试-重测可重复性。
11 名健康男性志愿者在两天内分别进行了两组 PET 研究，其中包括 [C]MNPA 和 [C]raclopride 扫描。计算尾状核和壳核中的 BP 值。通过个体内变异性（绝对变异性）和测试-重测可靠性（组内相关系数：ICC）评估 [C]MNPA 和 [C]MNPA/[C]raclopride 的 BP 的测试-重测可重复性。
尾状核和壳核中 [C]MNPA BP 的绝对变异性分别为 5.30±3.96%和 12.3±7.95%，[C]MNPA BP 的 ICC 值分别为 0.72 和 0.82。尾状核和壳核中 [C]MNPA/[C]raclopride 的绝对变异性分别为 6.11±3.68%和 11.60±5.70%，[C]MNPA/[C]raclopride 的 ICC 值分别为 0.79 和 0.80。
在本初步研究中，尾状核和壳核中 [C]MNPA 的 BP 和 [C]MNPA/[C]raclopride 的测试-重测可重复性可靠。
