IODINE-123-MIBG SPECT VERSUS PLANAR IMAGING IN CHILDREN WITH NEURAL CREST TUMORS

Iodine-123-metaiodobenzylguanidine (MIBG) SPECT was compared with I-12 3-MIBG planar imaging in 35 studies of 25 children with neural crest t umors. Methods: Iodine-123-MIBG (0.070-0.140 mCi/kg intravenously) was followed at 24 hr by whole-body planar imaging and triple-detector, h igh-resolution thoracoabdominal SPECT. At 48 hr, thoracoabdominal plan ar imaging was performed whenever a high-tissue background or gut acti vity interfered with the interpretation of the 24-hr planar images. SP ECT views included a cine loop presentation of multiple volume-rendere d projections. Two reviewers enumerated the number of abnormal sites o n the planar and SPECT studies and rated the certainty of interpretati on for each study on a scale from 0.1 (low certainty) to 1.0 (high). R esults: Abnormal uptake was noted on planar or SPECT imaging in 13 stu dies (seven patients). The average number of abnormal sites detected p er study for all 35 studies was 2.7 for planar imaging and 2.9 for SPE CT (p = not significant) (and 7.2 and 8.4 for planar and SPECT, respec tively, for the 13 abnormal studies). The certainty ratings for all 35 studies were 0.74 for planar studies, 0.82 for SPECT (p = 0.05, chi-s quare, compared with planar) and 0.86 for planar and SPECT combined (p = 0.01 compared with planar alone). On volume-rendered images, gut ac tivity was seen as diffuse and/or linear intraluminal activity. Conclu sion: When I-123-MIBG SPECT is used, the number of lesions detected is not increased, but there is a significant improvement in the certaint y of interpretation over planar imaging.