Purpose or Case Report: In the past, neuroblastoma patients frequently had mIBG and diagnostic CT scans performed at separate times. This practice sometimes caused issues in correlating findings from the two imaging modalities. A retrospective review of our entire experience aimed to confirm the added value of optimized co-registered contrast-enhanced diagnostic CT to I-123 mIBG SPECT/CT protocol in children with neuroblastoma. An additional objective was to identify if SPECT/CT improved Curie score assignment vs planar imaging.
Methods & Materials: We previously reported on a limited recent experience of optimized mIBG SPECT/CT. We have now completed a retrospective review of 384 SPECT/CT scans of pediatric neuroblastoma patients (aged 0 to 18 years) performed from April 2007 to June 2018. Added value of the co-registered CT was categorized as providing: increased sensitivity, improved localization, improved tumour delineation, improved differentiation between malignant and physiological or benign findings, detection of additional incidental findings, and/or no additional value when fused with the I-123 mIBG scintigraphy. Chi-square tests were performed to assess differences between diagnosis vs follow-up scans with added value from the co-registered CT. Curie score evaluation was performed using planar and SPECT/CT imaging.
Results: Of all assessed scans, 70% of co-registered contrast-enhanced diagnostic CT studies performed as part of the SPECT/CT scan provided added value (87% of staging scans at diagnosis (n=47), 67% in follow-up (n=337)). Overall, use of co-registered CT enhanced diagnostic sensitivity, tumour localization and delineation, and differentiation of malignant versus benign findings in many cases, and also identified additional incidental findings. Curie score assessment was improved in areas of equivocal lesions involving mainly the torso and particularly on follow-up examinations.
Conclusions: Optimized mIBG SPECT/CT can reduce the need for additional imaging studies by improving accuracy of disease characterization and Curie score.