ARE 3-DIMENSIONAL SURFACE-SHADED SPET IMAGES BETTER THAN PLANAR AND CORONAL SPET IMAGES IN THE ASSESSMENT OF REGIONAL PULMONARY PERFUSION

Although single photon emission tomographic (SPET) imaging has been sh own to be more sensitive than planar imaging in the diagnosis of pulmo nary embolism, it has yet to be used routinely in clinical practice. T he aims of this study were (1) to compare a new three-dimensional surf ace-shaded version of SPET (3-D SPET) with conventional planar imaging and coronal SPET slices, and (2) to evaluate observer agreement among these three modalities in the assessment of regional pulmonary perfus ion. Compared with a consensus score (based on revised PIOPED criteria ) of 29 cases, including nine with a clinical diagnosis of pulmonary e mbolism, 3-D SPET showed the highest number of normal scans, suggestin g better specificity than planar or coronal SPET images. Five observer s evaluated the three image sets twice within a 3-6 month period. Agre ement with the consensus score was slightly better for the second read ing and the average perfect agreement was 71-76%. No one image set was superior to any other in this respect. In conclusion, the number of n ormal scans using 3-D SPET is significantly greater relative to planar and coronal SPET scans as defined by the consensus view. Observer agr eement rates are very similar with all three modalities.