Arakawa Ryosuke, Stenkrona Per, Takano Akihiro, Nag Sangram, Maior Rafael S, Halldin Christer
Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.
Primate Center and Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia, Brazil.
EJNMMI Res. 2017 Dec;7(1):54. doi: 10.1186/s13550-017-0301-4. Epub 2017 Jun 20.
[C]-L-deprenyl-D is a positron emission tomography (PET) radioligand for measurement of the monoamine oxidase B (MAO-B) activity in vivo brain. The estimation of the test-retest reproducibility is important for accurate interpretation of PET studies.
We performed two [C]-L-deprenyl-D scans for six healthy subjects and evaluated the test-retest variability of this radioligand. MAO-B binding was quantified by two tissue compartment model (2TCM) with three rate constants (K , k , k ) using metabolite-corrected plasma radioactivity. The λk defined as (K /k ) × k was also calculated. The correlation between MAO-B binding and age, and the effect of partial volume effect correction (PVEc) for the reproducibility were also estimated. %difference of k was 2.6% (medial frontal cortex) to 10.3% (hippocampus), and that of λk was 5.0% (thalamus) to 9.2% (cerebellum). Mean %difference of all regions were 5.3 and 7.0% in k and λk , respectively. All regions showed below 10% variabilities except the hippocampus in k (10.3%). Intraclass correlation coefficient (ICC) of k was 0.78 (hippocampus) to 0.98 (medial frontal cortex), and that of λk was 0.78 (hippocampus) to 0.95 (thalamus). Mean ICC were 0.94 and 0.89 in k and λk , respectively. The highest positive correlation with age was observed in the hippocampus, as r = 0.75 in k and 0.76 in λk . After PVEc, mean %difference were 5.6 and 7.2% in k and λk , respectively. Mean ICC were 0.92 and 0.90 for k and λk , respectively. These values were almost the same as those before PVEc.
The present results indicate that k and λk of [C]-L-deprenyl-D are reliable parameters for test-retest reproducibility with healthy subjects both before and after PVEc. The studies with patients of larger sample size are required for further clinical applications.
[C]-L-司来吉兰-D是一种正电子发射断层扫描（PET）放射性配体，用于测量活体大脑中的单胺氧化酶B（MAO-B）活性。重测再现性的评估对于PET研究的准确解释很重要。
我们对6名健康受试者进行了两次[C]-L-司来吉兰-D扫描，并评估了这种放射性配体的重测变异性。使用代谢物校正的血浆放射性，通过具有三个速率常数（K、k、k）的双组织室模型（2TCM）对MAO-B结合进行定量。还计算了定义为（K/k）×k的λk。还估计了MAO-B结合与年龄之间的相关性以及部分容积效应校正（PVEc）对再现性的影响。k的%差异在2.6%（内侧额叶皮质）至10.3%（海马体）之间，λk的%差异在5.0%（丘脑）至9.2%（小脑）之间。所有区域k和λk的平均%差异分别为5.3%和7.0%。除海马体的k（10.3%）外，所有区域的变异性均低于10%。k的组内相关系数（ICC）在0.78（海马体）至0.98（内侧额叶皮质）之间，λk的ICC在0.78（海马体）至0.95（丘脑）之间。k和λk的平均ICC分别为0.94和0.89。在海马体中观察到与年龄的最高正相关性，k的r值为0.75，λk的r值为0.76。进行PVEc后，k和λk的平均%差异分别为5.6%和7.2%。k和λk的平均ICC分别为0.92和0.9。这些值与PVEc之前的值几乎相同。
目前的结果表明，[C]-L-司来吉兰-D的k和λk是健康受试者在PVEc前后重测再现性的可靠参数。进一步的临床应用需要对更大样本量的患者进行研究。
