Iannotti F, Fieschi C, Alfano B, Picozzi P, Mansi L, Pozzilli C, Punzo A, Del Vecchio G, Lenzi G L, Salvatore M
J Comput Assist Tomogr. 1987 May-Jun;11(3):390-7. doi: 10.1097/00004728-198705000-00004.
Blood-brain barrier (BBB) permeability to [68Ga]EDTA was measured by positron emission tomography (PET) in four normal volunteers and in 11 patients with brain tumors. A unidirectional transfer constant, Ki, was calculated applying multiple-time graphical analysis (MTGA). This method allows the detection of backflux from brain to blood and, by generalization, the measurement of the constant Kb (brain to blood). Furthermore, the need for an independent measurement of the intravascular tracer is obviated: MTGA itself provides an estimate of the cerebral plasma volume (Vp). In the four normal volunteers the Ki was 3.0 +/- 0.8 X 10(-4) ml g-1 min-1 (mean +/- SD) and the Vp 0.034 +/- 0.007 ml g-1. A net increase in Ki up to a maximum of 121.0 X 10(-4) ml g-1 min-1 (correspondent value of Kb = 0.025 min-1) as well as an increase of Vp was observed in malignant tumors. The input function was calculated using both the [68Ga]EDTA concentration in sequential arterial blood samples and, noninvasively, the activity derived from the superior sagittal sinus image. The values of Ki and Vp from these two calculations were in good agreement. The application of MTGA to PET permits the evaluation of passage of substances across the BBB without making assumptions about the compartments in which the tracer distributes.
通过正电子发射断层扫描（PET）测量了4名正常志愿者和11名脑肿瘤患者血脑屏障（BBB）对[68Ga]EDTA的通透性。应用多次图形分析（MTGA）计算单向转运常数Ki。该方法能够检测从脑到血的反流，并通过推广来测量常数Kb（从脑到血）。此外，无需独立测量血管内示踪剂：MTGA本身可提供脑血浆容积（Vp）的估计值。4名正常志愿者的Ki为3.0±0.8×10−4 ml g−1 min−1（均值±标准差），Vp为0.034±0.007 ml g−1。在恶性肿瘤中观察到Ki净增加，最高可达121.0×10−4 ml g−1 min−1（对应Kb值=0.025 min−1），同时Vp也增加。输入函数通过连续动脉血样中[68Ga]EDTA浓度以及从矢状窦图像无创获得的活性来计算。这两种计算得出的Ki和Vp值吻合良好。将MTGA应用于PET可在不假设示踪剂分布隔室的情况下评估物质通过BBB的情况。
