Purpose or Case Report: The purpose of this exhibit is explore pitfalls in our experience with SPECT-CT Iodine-123 (I-123) MIBG imaging in patients with neuroblastoma. SPECT-CT can more specifically localize areas of uptake over planar imaging and mitigate false-positive results with correlative anatomic information. We will review cases of false-positive MIBG uptake in nonmalignant sites, cases of false-negative MIBG uptake in neuroblastoma/neural crest tumors, and cases of secondary tumors/malignancies occurring in the setting of known neuroblastoma, with variable uptake on MIBG.
Methods & Materials: Pictorial, retrospective review of key false positive and false negative cases of I-123 MIBG uptake in neuroblastoma imaging.
-Review of normal MIBG uptake and excretion
-Significance of SPECT positive but planar negative findings on Curie score
-Imaging artifacts (misalignment/mis-coregistration, etc.)
-Physiologic cases of false positive increased uptake in benign/non-malignant sites (glomerulonephritis/pyelonephritis, renal vein thrombosis, remaining unilateral adrenal gland, brown fat, thyroid gland, skeletal muscles, lungs, liver. Additional false positive uptakes localizing to previously treated neuroblastoma and representing post-surgical changes.
-Explore false negative MIBG uptake in neuroblastoma or neural crest tumors (i.e. ganglioneuroma and metastatic neuroblastoma liver lesions showing little to no uptake.) Key Point: Non-MIBG avid neuroblastoma may require troubleshooting with 18F-DOPA or 18F-FDG PET-CT.
- Review cases of secondary tumors/malignancies occurring in the setting neuroblastoma, with variable uptake on MIBG (Increased MIBG uptake in renal cell carcinoma and medullary thyroid carcinoma; no MIBG uptake in myofibroma of the jaw and a mucoepidermoid salivary gland tumor.) Key Point: Suggest further dedicated imaging and correlation with tissue sampling if a lesion is suspected clinically.
Results: A pictorial review of false positive and false negative cases at SPECT-CT I-123 MIBG imaging of neuroblastoma patients will be discussed. SPECT-CT may help localize areas of uptake and minimize false-positive results.
Conclusions: Recognizing pitfalls during SPECT-CT I-123 MIBG imaging of neuroblastoma patients will help radiologists correctly interpret findings and help guide proper treatment and management.