Department of Radiology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osaka-Sayama, Osaka, 589-8511, Japan.
Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohnohigashi, Osaka-Sayama, Osaka, 589-8511, Japan.
Ann Nucl Med. 2020 Nov;34(11):856-863. doi: 10.1007/s12149-020-01513-3. Epub 2020 Aug 27.
It is usually easy to judge whether amyloid PET images should be interpreted as positive or negative for amyloid deposits by visual inspection or quantitative measurement standard uptake value ratio (SUVR), but the findings are equivocal in some cases. As conventional mean cortical SUVR (mcSUVR) measures accumulation in both gray matter (GM) and white matter, it may mis-estimate amyloid deposits. The purpose of the study was to develop a regional GM-dedicated SUVR measuring (GMSUVR) system for amyloid PET images with 3D-MRI, and evaluate its utility for detecting amyloid deposits in equivocal cases.
Of 126 subjects who underwent amyloid PET with C-PiB and 3D-MRI, the area of amyloid-positive regions and the critical regional GMSUVR thresholds were first determined in 15 amyloid-positive and 15 amyloid-negative patients, using the automatic volumetric measurement of segmented brain images system. We then tested 36 amyloid-negative, 60 amyloid-positive, and 13 equivocal subjects with this GMSUVR system and with conventional mcSUVR.
Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 100%, 92%, 97%, 95%, and 100% for the GMSUVR system; and 97%, 86%, 93%, 92% and 94%, respectively, for mcSUVR. In 24 cases in which the findings were equivocal or discordant, the sensitivity, specificity, accuracy, PPV, and NPV were all 100% for the GMSUVR system; and were 90%, 33%, 83%, 90%, and 33%, respectively, for mcSUVR.
The regional GMSUVR measurement method was well able to discriminate between amyloid-positive and -negative subjects, even in cases where amyloid deposition was equivocal.
通过视觉检查或定量测量标准摄取值比（SUVR），通常很容易判断淀粉样 PET 图像是否应为淀粉样沉积物呈阳性或阴性，但在某些情况下结果存在争议。由于常规平均皮质 SUVR（mcSUV）测量值同时反映了灰质（GM）和白质（WM）的积累，因此可能会错误估计淀粉样沉积物。本研究旨在开发一种基于 3D-MRI 的区域 GM 专用 SUVR 测量系统（GMSUVR），并评估其在不确定病例中检测淀粉样沉积物的效用。
在 126 例接受 C-PiB 淀粉样 PET 和 3D-MRI 的受试者中，首先在 15 例淀粉样阳性和 15 例淀粉样阴性患者中使用自动容积测量分割脑图像系统确定了淀粉样阳性区域的面积和临界区域 GMSUVR 阈值。然后，我们使用此 GMSUVR 系统和常规 mcSUV 测试了 36 例淀粉样阴性、60 例淀粉样阳性和 13 例不确定的受试者。
对于 GMSUVR 系统，敏感性、特异性、准确性、阳性预测值（PPV）和阴性预测值（NPV）分别为 100%、92%、97%、95%和 100%；而对于 mcSUV 分别为 97%、86%、93%、92%和 94%。在 24 例结果不确定或不一致的病例中，GMSUVR 系统的敏感性、特异性、准确性、PPV 和 NPV 均为 100%；而对于 mcSUV，分别为 90%、33%、83%、90%和 33%。
即使在淀粉样沉积不确定的情况下，区域 GMSUVR 测量方法也能很好地区分淀粉样阳性和阴性受试者。
