Acetazolamide challenge testを含むγ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment（REICA）法による脳血流量の定量化の妥当性．

Validity of the γ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment (REICA) method for quantification of cerebral blood flow including acetazolamide challenge test.

抄録

目的:

γ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment（REICA）は，単光子放射型コンピュータ断層撮影（SPECT）と［I］N-isopropyl-p-iodoamphetamine（I-IMP）による新しい脳血流定量化法である．本研究では，acetazolamide challenge testを含むデータを用いて，REICA法の妥当性を検証した．

OBJECTIVE: The γ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment (REICA) is a new method for quantifying cerebral blood flow (CBF) using single-photon emission computed tomography (SPECT) and [I]N-isopropyl-p-iodoamphetamine (I-IMP). The present study aimed to validate the REICA method using data including acetazolamide challenge test.

方法:

REICA法とGraph-Plot（GP）法を用いて、92名（安静時：57名、ストレス時：35名）の獲得平均CBF（mCBF）、33名の脳血管反応性（CVR）を算出した。ストレスデータは、I-IMP投与10分前にacetazolamide 15mg/kgを静脈内投与し、restデータと同じ条件で採血を行った。基準として動脈血採取によるARG（Autoradiograph）法を用い、それぞれの方法と比較することでREICA法の精度を解析した。

METHODS: The REICA and Graph-Plot (GP) methods were used to calculate mean CBF (mCBF) for 92 acquisitions (rest: 57, stress: 35) and cerebrovascular reactivity (CVR) in 33 patients. To obtain stress data, 15 mg/kg of acetazolamide was injected intravenously 10 min before the administration of I-IMP, and blood samples were collected under the same conditions as rest data. The reference standard was the Autoradiograph (ARG) method using arterial blood sampling, and the accuracy of the REICA method was analyzed by comparing it with each method.

結果:

mCBFの相関係数（r）はREICA法0.792，GP法0.636であった。CVRでは，REICA法0.660，GP法0.578であった．両者ともGP法よりREICA法の方がARG法との相関が強かった。mCBFについては，両者の相関係数に有意差があった（p<0.01）。

RESULTS: For mCBF, the correlation coefficients (r) were 0.792 for the REICA method and 0.636 for the GP method. For CVR, r values were 0.660 for the REICA method and 0.578 for the GP method. In both acquisitions, the REICA method had a stronger correlation with the ARG method than the GP method. For mCBF, there was a significant difference in the correlation coefficient between the two correlation coefficients (p < 0.01).

結論:

REICA法はGP法よりもCBFの定量化精度が高く、ARG法に近いものであった。I-IMPを用いた非侵襲的脳血流定量法であるREICA法は，医療的有用性が高い．

CONCLUSIONS: The REICA method was more accurate than the GP method in quantifying CBF and closer to the ARG method. The REICA method, which is a noninvasive method of cerebral blood flow quantification using I-IMP, has great medical usefulness.