Guidelines on nuclear medicine imaging in neuroblastoma.

Nuclear medicine has a central role in the diagnosis, staging, response assessment and long-term follow-up of neuroblastoma, the most common solid extracranial tumour in children. These EANM guidelines include updated information on 123I-mIBG, the most common study in nuclear medicine for the evaluation of neuroblastoma, and on PET/CT imaging with 18F-FDG, 18F-DOPA and 68Ga-DOTA peptides. These PET/CT studies are increasingly employed in clinical practice. Indications, advantages and limitations are presented along with recommendations on study protocols, interpretation of findings and reporting results.

123I-mIBG scintigraphy in neuroblastoma: development of a SIOPEN semi-quantitative reporting ,method by an international panel.

PURPOSE: A robust method is required to standardise objective reporting of diagnostic 123I-mIBG images in neuroblastoma. Prerequisites for an appropriate system are low inter- and intra-observer error and reproducibility across a broad disease spectrum. We present a new reporting method, developed and tested for SIOPEN by an international expert panel. METHOD: Patterns of abnormal skeletal 123I-mIBG uptake were defined and assigned numerical scores [0-6] based on disease extent within 12 body segments. Uptake intensity was excluded from the analysis. Data sets from 82 patients were scored independently by six experienced specialists as unblinded pairs (pre- and post-induction chemotherapy) and in random order as a blinded study. Response was defined as ≥50 % reduction in post induction score compared with baseline. RESULTS: In total, 1968 image sets were reviewed individually. Response rates of 88 % and 82 % were recorded for patients with baseline skeletal scores ≤23 and 24-48 respectively, compared with 44 % response in patients with skeletal scores >48 (p = 0.02). Reducing the number of segments or extension scale had a small but statistically negative impact upon the number of responses detected. Intraclass correlation coefficients [ICCs] calculated for the unblinded and blinded study were 0.95 at diagnosis and 0.98 and 0.99 post-induction chemotherapy, respectively. CONCLUSIONS: The SIOPEN mIBG score method is reproducible across the full spectrum of disease in high risk neuroblastoma. Numerical assessment of skeletal disease extent avoids subjective evaluation of uptake intensity. This robust approach provides a reliable means with which to examine the role of 123I mIBG scintigraphy as a prognostic indicator in neuroblastoma.

Skeletal involvement in infants with neuroblastoma a quality control attempt.

AIMS AND BACKGROUND: In 1994, French authors hypothesized that positive skeletal mlBG spots in infants with stage 4 neuroblastoma were not prognostically unfavorable unless associated to abnormal standard X-ray or CT findings. In 1999, the European Infant Neuroblastoma Study adopted this definition, indeed reducing the number of patients candidate to chemotherapy. Such an approach requires high quality scans and standardized procedures. The present study critically reviewed and assessed the quality of mlBG scans performed in Italian patients enrolled in the European Infant Neuroblastoma Study. METHODS: Three independent nuclear medicine specialists reviewed scans of 25 Italian patients enrolled in Trials 99.2, 99.3, and 99.4 of the European Infant Neuroblastoma Study between January 2000 and September 2002. An arbitrary quality score was attributed to each mlBG scintigraphy, ranging from 1 (less than adequate) to 3 (excellent). One radiologist and 2 oncologists reviewed the X-rays and CT scans and correlated the results with clinical assessment. RESULTS: The quality of mlBG scans was rated from good to excellent in 15 of 25 cases, poor in 4, and inadequate for diagnostic evaluation in 6. X-rays confirmed the presence of metastases in 3 of 7 cases with mlBG bone uptake. CT scan confirmed skull metastases in 6 of 9 mlBG-positive cases. Discrepancies in scan interpretation, making trial and stage attribution questionable, were found in 2 patients and are discussed. CONCLUSIONS: The quality of mlBG scans proved to be at least acceptable in most Italian pediatric oncology centers. Efforts should be made to further standardize evaluation of the scans. Additional techniques (99mTc scintigraphy, MRI, SPECT) might be useful to help understand the most complex cases.