RENAL TC-99(M)-DMSA SPET AND PLANAR IMAGING ARE THEY REALLY THE SAME - ARE THEY REALLY THE SAME

Previous studies have suggested that more defects are detected on SPET than on planar DMSA images. The aim of this study was to evaluate dif ferences between planar and SPET imaging. Sixty-four kidneys from pyel onephritic patients were studied using both techniques. An automated a lgorithm for reorientation and centring of the SPET images was used to minimize inter-observer variability. Reduced uptake and contour defec ts showed different localization on planar and SPET imaging. Coinciden ce of defects on both types of image was low. We also noted a dependen ce on defect frequency content for detectability. Image contrast playe d a noticeable role in the detection of defects. Differences in contra st between SPET and planar images may be responsible for the variable success in the detection of defects. Contour defects are seen more fre quently on tomographic slices, whereas reduced uptake defects are seen more frequently on planar images. A difference is also noted between the cortical and calyceal zones for differently contrasted lesions. SP ET and planar DMSA images can potentially provide a different diagnosi s of renal lesions.