Purpose or Case Report: Neuroblastoma is the most common extracranial solid malignancy in children. It can have a variety of clinical outcomes, ranging from spontaneous resolution without therapy to fatal outcomes resistant to maximal therapy.

Historically, neuroblastoma has been staged using the International Neuroblastoma Staging System (INSS). While this staging system has been used in clinical trials since its introduction in 1989, its reliance on surgical staging is problematic. Surgical resection can vary between surgeons and between tumors and occurs at an interval from diagnosis. This method complicates the process of standardizing therapy. Additionally, some patients have a disease that spontaneously regresses and does not require surgical management and thus cannot be staged.

To combat these problems, the International Neuroblastoma Risk Group (INRG) created a new staging system for use in clinical trials in 2009. This staging system relies on preoperative imaging for up-front staging. This helps standardize neuroblastoma staging and helps to guide a more standard approach to management. The INRG staging system is comprised of twenty image-defined risk factors (IDRF), across multiple organ systems, which help predict surgical outcomes and can be combined with clinical data to provide up-front risk stratification.

Even though the INRG staging system has been in use since 2009, many pediatric radiologists remain unfamiliar with its definitions and application. Additionally, MR has now become an essential imaging tool for diagnosis, staging, and follow-up of patients with neuroblastoma. The purpose of this poster is to compare the INSS and INRG staging system, describe the limitations of each system, and illustrate the definitions and IDRFs that comprise the INRG staging system.
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