Clinical Utility of Masking in Planar and Single-Photon Emission Computed Tomography/Computed Tomography Lung Perfusion Imaging in the Presence of 99mTc-Macroaggregated Albumin Embolus.

A 74-year-old male with lung cancer in right lower lobe underwent lung perfusion planar imaging and SPECT/CT scan for preoperative evaluation. A focal intense uptake artifact was shown on the initial scan, prompting a repeat scan 5 days later. A MAA embolus artifact can disrupt the analysis of radioactivity in each lung segment, potentially causing errors in postoperative residual lung function. Consequently, repeat imaging or correction may be necessary. When repeat images without MAA embolus were used for comparison, applying a mask to exclude the MAA embolus lesion provided reliable results, eliminating the need for further repeat imaging.