The truncation artefact in patients with a high body mass index on myocardial perfusion SPECT.

To cite: Matsumoto N, Suzuki Y, Yoda S, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014205407 DESCRIPTION Recognition of the truncation artefact is important for the control of image quality on myocardial perfusion images in single-photon emission CT (SPECT). Truncation artefact is usually seen in obese patients who may deviate from a γ-ray detector field. The deviation of the body in the limited detector field sometimes causes the truncation of the left ventricle and low image quality. We encountered the truncation artefact in patients with a high body mass index (34.2) which raises the possibility of an unusual detector arc in the non-circular detector orbit. Figure 1A depicts a presence of the truncation of the detector field in the 29th projection without the truncation of the left ventricle. Figure 1B does not show the truncation of the detector field in the same 29th projection after the optimisation of the patient’s body location. This type of ‘field truncation’ causes the low image quality in the corresponding reconstructed short-axis siles (figure 2A); with the field truncation. Figure 2B without the field truncation shows normal perfusion image. The presence of truncation artefact can be recognised by following two methods. First is the presence of ununiformity of the raw projection field (figure 1A), second is