Impact of the Adaptive Statistical Iterative Reconstruction Technique on Radiation Dose and Image Quality in Bone SPECT/CT

Louis Sibille (1) , Benjamin Chambert (1) , Sandrine Alonso (2) , Corinne Barrau (1) , Emmanuel d'Estanque (1) , Yassine Al Tabaa (1, 3) , Laurent Collombier (1) , Christophe Demattei (2, 4) , Pierre-Olivier Kotzki (1, 5) , Vincent Boudousq (1, 5)

1 CHU Nîmes - Centre Hospitalier Universitaire de Nîmes
2 BESPIM
3 UM - Université de Montpellier
4 AIDMP - Aide à la Décision pour une Médecine Personnalisé - Laboratoire de Biostatistique, Epidémiologie et Recherche Clinique - EA 2415
5 IRCM - U1194 Inserm - UM - Institut de Recherche en Cancérologie de Montpellier

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). METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Mots clés: CT optimization; SPECT/CT; adaptive statistical iterative reconstruction (ASiR); attenuation correction; bone scintigraphy

Domaines: Imagerie; Médecine nucléaire; Médecine humaine et pathologie

Louis Sibille, Benjamin Chambert, Sandrine Alonso, Corinne Barrau, Emmanuel d'Estanque, et al.. Impact of the Adaptive Statistical Iterative Reconstruction Technique on Radiation Dose and Image Quality in Bone SPECT/CT. Journal of Nuclear Medicine, 2016, 57 (7), pp.1091 - 1095. ⟨10.2967/jnumed.115.164772⟩. ⟨hal-01906726⟩