Techniques for generating attenuation map using cardiac SPECT emission data only: a systematic review

To reliably interpret and perform quantitative analysis, attenuation correction for cardiac single-photon emission computed tomography (SPECT) is fundamental. Thus, knowledge of the patient-specific attenuation map for accurate correction is required in SPECT quantitative imaging. The aim of this systematic review is to present general principles of attenuation correction and provide a structured summary of the approaches that have been proposed for generating the attenuation map for cardiac SPECT. We identified relevant articles published in English pertaining to the attenuation map (AM) determination using SPECT emission data only by searching PubMed, EMBASE, Scopus, and Web of Science databases. Moreover, other articles were hand searched. The protocol of this systematic review was registered in PROSPERO and the code given is CRD42017060512. Transmissionless techniques of determining attenuation map including calculated methods, statistical modeling for simultaneous estimation of attenuation and emission, consistency conditions criteria, using scattered data and other methods were reviewed. Methods for performing attenuation map for cardiac SPECT are developing and the progresses made are promising. However, much work is needed to assess the efficacy of the correction schemes in the clinical routine.