High-resolution multi-detector SPET imaging of the paediatric spine.

We reviewed the planar and single photon emission tomographic (SPET) spine images of 69 paediatric patients aged 2-17 years referred for undiagnosed back pain. The SPET images were obtained using a triple-detector camera and ultra-high-resolution collimation. Abnormal images were rated as slightly positive (1+) or strongly positive (2+). The planar and SPET images were normal in 48 of 69 patients. Thirteen of the remaining 21 cases had negative planar imaging with positive SPET images (SPET was 2+ in 10 cases and 1+ in 3 cases). Four of the 21 cases were 1+ on planar imaging, but clearly positive (2+) on the SPET images. Three of the 21 cases had 2+ planar abnormalities, but SPET demonstrated additional uptake abnormalities. Lastly, a single case that was 2+ on the planar images was demonstrated to be artefactual by SPET. Thirty-seven sites were abnormal by SPET, including 17 pedicle/parts interarticularis (11 patients), 10 spinous process (8 patients), 8 vertebral endplate (2 patients) and 2 vertebral body (2 patients) abnormalities. Sites that were abnormal on SPET and normal on planar imaging included 10 of 17 (59%) in the pedicle/pars region, 9 of 10 (90%) in the spinous process, 1 of 2 (50%) in the vertebral body and 2 of 8 (25%) in the vertebral endplates. The improved resolution of ultra-high-resolution collimated multi-detector SPET permits visualization of a greater variety of abnormalities than was seen with earlier single-detector cameras, particularly those involving the spinous process.

Iodine-123-MIBG SPECT versus planar imaging in children with neural crest tumors.

UNLABELLED: Iodine-123-metaiodobenzylguanidine (MIBG) SPECT was compared with 123I-MIBG planar imaging in 35 studies of 25 children with neural crest tumors. METHODS: Iodine-123-MIBG (0.070-0.140 mCi/kg intravenously) was followed at 24 hr by wholebody planar imaging and triple-detector, high-resolution thoraco-abdominal SPECT. At 48 hr, thoracoabdominal planar imaging was performed whenever a high-tissue background or gut activity interfered with the interpretation of the 24-hr planar images. SPECT views included a cine loop presentation of multiple volume-rendered projections. Two reviewers enumerated the number of abnormal sites on the planar and SPECT studies and rated the certainty of interpretation for each study on a scale from 0.1 (low certainty) to 1.0 (high). RESULTS: Abnormal uptake was noted on planar or SPECT imaging in 13 studies (seven patients). The average number of abnormal sites detected per study for all 35 studies was 2.7 for planar imaging and 2.9 for SPECT (p = not significant) (and 7.2 and 8.4 for planar and SPECT, respectively, 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-square, compared with planar) and 0.86 for planar and SPECT combined (p = 0.01 compared with planar alone). On volume-rendered images, gut activity was seen as diffuse and/or linear intraluminal activity. CONCLUSION: When 123I-MIBG SPECT is used, the number of lesions detected is not increased, but there is a significant improvement in the certainty of interpretation over planar imaging.

Neural crest tumors: I-123 MIBG imaging in children.

PURPOSE: To determine 24- and 48-hour distribution of iodine-123 metaiodobenzylguanidine (MIBG) and to establish an optimized pediatric imaging protocol. MATERIALS AND METHODS: Seventy-seven I-123 MIBG scans obtained in 33 children undergoing evaluation for neural crest tumor were reviewed. RESULTS: Activity in the salivary glands, myocardium, liver, gut, and bladder was demonstrated on almost all scans. Activity was noted in the neck muscles, thyroid gland, and uninvolved adrenal gland in fewer studies. In 20 studies, abnormal uptake was present in the chest or abdomen at 24 and 48 hours, and lesion identification was improved at 48 hours in 12 studies. Detection of skeletal lesions on 14 scans was similar at 24 and 48 hours. Foci of tumor were first detected at I-123 MIBG imaging in nine studies, and in only two patients was tumor involvement initially missed on I-123 MIBG studies. CONCLUSION: Distribution of I-123 MIBG on images in children differs from that in earlier descriptions in adults. Images of the torso at 48 hours after injection are a useful adjunct in detection of lesions.