Performed at one institution, Observational, Retrospective, Metastases, Education, MR-Diffusion/Perfusion, Paediatric, Oncology, Nuclear medicine, Oncologic Imaging
M. C. Colombo1, E. J. Inarejos Clemente2, J. Munuera1, A. Castañeda1, J. Mora1, I. Barber3; 1Barcelona/ES, 2Esplugues de Llobregat, Barcelona/ES, 3Esplugues de Llobregat (Barcelona)/ES
Evaluation of metastatic bone disease, including response assessment to chemotherapy, in patients with stage IV neuroblastoma is key for the correct management of these patients (1).
Diffusion-weighted MR allows the assessment of Brownian motion in various tissue water molecules. Using different b values allows for the quantification of signal loss in diffusion-sensitive sequences by means of apparent diffusion coefficient (ADC) maps. It has been proved that highly dense cellular areas restrict motion of extracellular water molecules. High cellularity is related to restricted diffusion and low ADC values in comparison to areas with less cellular density, that show higher ADC values (2).
Radiolabeled metaiodobenzylguanidine (MIBG) with iodine-123 is a powerful tool with a sensitivity of around 90% and a specificity close to 100% for the diagnosis of NBL. MBG is considered to be the gold standard for the evaluation of NBL bone marrow involvement and/or cortical bone metastases in our centre (1,4).
Our hypothesis is that MRI is useful in the detection of bone involvement in NBL and that quantitative DWI is able to differentiate low cell density skeletal lesions (which might be considered as non-active or residual) from highly cellular lesions (associated with tumour viability) (2,8). For this purpose, a retrospective study was designed in order to compare whole-body DWI MR and MIBG in the assessment (after conventional chemotherapy treatment) of metastatic osseous lesions in patients with stage IV NBL who had received conventional chemotherapy.