USE OF THE SELECTIVE LINOGRAM IN CARDIAC TOMOGRAPHY QUALITY-CONTROL

Background. Quality control for detection of patient motion is essenti al in tomographic myocardial imaging. Despite significant limitations, the summation image or conventional ''linogram'' has long been advoca ted as a useful image in the detection of vertical motion. In this stu dy a new quality control image entitled the ''selective linogram'' is proposed to replace the summation image in routine cardiac single-phot on emission cardiac tomography (SPECT) quality control. The selective linogram is constructed in a manner somewhat analogous to the sinogram . In the sinogram, each row represents a different projection angle; i n the selective linogram each column represents a different projection angle. Methods and Results. After selection of eight motion-free stud ies from acquisitions at our clinical center, vertical motion of vario us types (bounces, shifts, and creep) were added to the projection fra mes. Summation image and selective linogram quality control images fro m these motion-containing studies and the original motion-free studies were presented in a blinded manner to two observers for scoring of pa tient motion. The selective linogram was significantly more accurate i n allowing detection of vertical motion than was the summation image ( accuracy 89% vs 47%). Conclusions. The selective linogram image is mar kedly superior to the summation image for the detection of vertical pa tient motion during cardiac SPECT. This new technique can be a valuabl e aid in SPECT quality control.