Sibille Louis, Chambert Benjamin, Alonso Sandrine, Barrau Corinne, D'Estanque Emmanuel, Al Tabaa Yassine, Collombier Laurent, Demattei Christophe, Kotzki Pierre-Olivier, Boudousq Vincent
Department of Nuclear Medicine, Nîmes University Hospital, Nîmes, France; and
Department of Nuclear Medicine, Nîmes University Hospital, Nîmes, France; and.
J Nucl Med. 2016 Jul;57(7):1091-5. doi: 10.2967/jnumed.115.164772. Epub 2016 Mar 24.
The purpose of this study was to compare a routine bone SPECT/CT protocol using CT reconstructed with filtered backprojection (FBP) with an optimized protocol using low-dose CT images reconstructed with adaptive statistical iterative reconstruction (ASiR).
In this prospective study, enrolled patients underwent bone SPECT/CT, with 1 SPECT acquisition followed by 2 randomized CT acquisitions: FBP CT (FBP; noise index, 25) and ASiR CT (70% ASiR; noise index, 40). The image quality of both attenuation-corrected SPECT and CT images was visually (5-point Likert scale, 2 interpreters) and quantitatively (contrast ratio [CR] and signal-to-noise ratio [SNR]) estimated. The CT dose index volume, dose-length product, and effective dose were compared.
Seventy-five patients were enrolled in the study. Quantitative attenuation-corrected SPECT evaluation showed no inferiority for contrast ratio and SNR issued from FBP CT or ASiR CT (respectively, 13.41 ± 7.83 vs. 13.45 ± 7.99 and 2.33 ± 0.83 vs. 2.32 ± 0.84). Qualitative image analysis showed no difference between attenuation-corrected SPECT images issued from FBP CT or ASiR CT for both interpreters (respectively, 3.5 ± 0.6 vs. 3.5 ± 0.6 and 3.6 ± 0.5 vs. 3.6 ± 0.5). Quantitative CT evaluation showed no inferiority for SNR between FBP and ASiR CT images (respectively, 0.93 ± 0.16 and 1.07 ± 0.17). Qualitative image analysis showed no quality difference between FBP and ASiR CT images for both interpreters (respectively, 3.8 ± 0.5 vs. 3.6 ± 0.5 and 4.0 ± 0.1 vs. 4.0 ± 0.2). Mean CT dose index volume, dose-length product, and effective dose for ASiR CT (3.0 ± 2.0 mGy, 148 ± 85 mGy⋅cm, and 2.2 ± 1.3 mSv) were significantly lower than for FBP CT (8.5 ± 3.7 mGy, 365 ± 160 mGy⋅cm, and 5.5 ± 2.4 mSv).
The use of 70% ASiR blending in bone SPECT/CT can reduce the CT radiation dose by 60%, with no sacrifice in attenuation-corrected SPECT and CT image quality, compared with the conventional protocol using FBP CT reconstruction technique.
本研究的目的是比较使用滤波反投影（FBP）重建CT的常规骨SPECT/CT方案与使用自适应统计迭代重建（ASiR）重建的低剂量CT图像的优化方案。
在这项前瞻性研究中，纳入的患者接受骨SPECT/CT检查，先进行1次SPECT采集，然后进行2次随机CT采集：FBP CT（FBP；噪声指数，25）和ASiR CT（70% ASiR；噪声指数，40）。通过视觉（5分李克特量表，2名解读人员）和定量（对比率[CR]和信噪比[SNR]）评估衰减校正后的SPECT和CT图像的图像质量。比较CT剂量指数体积、剂量长度乘积和有效剂量。
75名患者纳入本研究。定量衰减校正后的SPECT评估显示，FBP CT或ASiR CT的对比率和SNR无劣势（分别为13.41±7.83对13.45±7.99以及2.33±0.83对2.32±0.84）。定性图像分析显示，两名解读人员对FBP CT或ASiR CT的衰减校正后SPECT图像之间无差异（分别为3.5±0.6对3.5±0.6以及3.6±0.5对3.6±0.5）。定量CT评估显示，FBP和ASiR CT图像之间的SNR无劣势（分别为0.93±0.16和1.07±0.17）。定性图像分析显示，两名解读人员对FBP和ASiR CT图像之间无质量差异（分别为为3.8±0.5对3.6±0.5以及4.0±0.1对4.0±0.2）。ASiR CT的平均CT剂量指数体积、剂量长度乘积和有效剂量（3.0±2.0 mGy、148±85 mGy·cm和2.2±1.3 mSv）显著低于FBP CT（8.5±3.7 mGy、365±160 mGy·cm和5.5±2.4 mSv）。
与使用FBP CT重建技术的传统方案相比，在骨SPECT/CT中使用70% ASiR混合可以将CT辐射剂量降低60%，且不牺牲衰减校正后的SPECT和CT图像质量。
