Institute of Neuroscience, Newcastle University, Biomedical Research Building, Campus for Ageing and Vitality, Westgate Road, Newcastle Upon Tyne. NE4 6BE, United Kingdom. Nuclear Medicine Department, Leazes Wing, Royal Victoria Infirmary, Richardson Road, Newcastle Upon Tyne. NE1 4LP, United Kingdom.
Biomed Phys Eng Express. 2019 Dec 19;6(1):015011. doi: 10.1088/2057-1976/ab5c09.
Planar I-MIBG (meta-iodobenzylguanidine) cardiac imaging is listed as an indicative biomarker in the 2017 international consensus criteria for the diagnosis of dementia with Lewy bodies. There has been very little research into the relationship between apparent cardiac uptake and patient size, or in the possible advantage of attenuation and scatter corrected SPECT-CT compared to planar imaging. We aimed to evaluate this in both a chest phantom and in older adults with normal cognition.
An anthropomorphic chest phantom was filled with I solution using activities typical of healthy subjects. The phantom was scanned on a Siemens Intevo gamma camera with MELP collimators using both planar and SPECT-CT techniques. Further scans were acquired with a PMMA chest plate added, then water filled plastic breasts. The SPECT-CT images were reconstructed using a resolution recovery OSEM method with and without attenuation and scatter correction (ACSC) applied. Twenty-nine adults over 60 years of age (mean 75.2 ± 8.3 years) underwent planar cardiac MIBG imaging, followed by SPECT-CT. SPECT images were reconstructed as above. Heart-to-mediastinum ratios (HMRs) were calculated for planar and SPECT images.
Phantom planar HMR decreased by 20% with the PMMA chest plate added; 39% with plate and breasts. ACSC SPECT cardiac counts showed less dependence on phantom size than SPECT without ACSC (3% versus 37%). The body mass indices (BMI) of the older adults ranged from 22 to 38. There was a significant linear relationship between planar HMR and BMI (R = 0.44, p<0.01), but not for ACSC SPECT. However, there was no significant difference between the slopes for planar and ACSC SPECT (p = 0.11).
Planar cardiac I-MIBG HMR results are correlated with BMI. Phantom results suggest that ACSC SPECT can correct for patient size. A large patient population or clinical database would be required to demonstrate a clinical effect.
平面 I-MIBG（间位碘代苄胍）心脏成像被列为路易体痴呆诊断的 2017 年国际共识标准中的指示性生物标志物。对于明显的心脏摄取与患者体型之间的关系，或者衰减和散射校正 SPECT-CT 相对于平面成像的可能优势，研究非常少。我们旨在同时在胸部体模和认知正常的老年人中评估这一点。
使用典型的健康受试者的活动，用 I 溶液填充人体模型。使用 MELP 准直器，在西门子 Intevo 伽玛相机上使用平面和 SPECT-CT 技术对体模进行扫描。进一步的扫描是在添加 PMMA 胸部板和充满水的塑料乳房后进行的。使用分辨率恢复 OSEM 方法进行 SPECT-CT 图像重建，应用和不应用衰减和散射校正 (ACSC)。29 名年龄在 60 岁以上的成年人（平均年龄 75.2±8.3 岁）接受了平面心脏 MIBG 成像，然后进行了 SPECT-CT。如上所述重建 SPECT 图像。计算平面和 SPECT 图像的心脏与纵隔比值 (HMR)。
添加 PMMA 胸部板后，体模平面 HMR 降低 20%；添加板和乳房后降低 39%。与未进行 ACSC 的 SPECT 相比，ACSC SPECT 心脏计数对体模大小的依赖性较小（3%与 37%）。老年人的体重指数（BMI）范围从 22 到 38。平面 HMR 与 BMI 呈显著线性关系（R=0.44，p<0.01），但 ACSC SPECT 则不然。然而，平面和 ACSC SPECT 的斜率之间没有显著差异（p=0.11）。
平面心脏 I-MIBG HMR 结果与 BMI 相关。体模结果表明，ACSC SPECT 可以校正患者体型。需要一个大型的患者群体或临床数据库来证明临床效果。
