A Diagnostic Algorithm for Posterior Fossa Tumors in Children: A Validation Study

• Published in: American journal of neuroradiology : AJNR 2021-05, Vol.42 (5), p.961-968
• Main Authors: Alves, C A P F, Löbel, U, Martin-Saavedra, J S, Toescu, S, Tsunemi, M H, Teixeira, S R, Mankad, K, Hargrave, D, Jacques, T S, da Costa Leite, C, Gonçalves, F G, Vossough, A, D'Arco, F
• Format: Article
• Language: English
• Subjects: Adolescent; Algorithms; Child; Child, Preschool; Editor's Choice; Female; Humans; Infant; Infratentorial Neoplasms - diagnosis; Infratentorial Neoplasms - pathology; Magnetic Resonance Imaging - methods; Male; Pediatrics
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.A7057

Primary posterior fossa tumors comprise a large group of neoplasias with variable aggressiveness and short and long-term outcomes. This study aimed to validate the clinical usefulness of a radiologic decision flow chart based on previously published neuroradiologic knowledge for the diagnosis of posterior fossa tumors in children. A retrospective study was conducted (from January 2013 to October 2019) at 2 pediatric referral centers, Children's Hospital of Philadelphia, United States, and Great Ormond Street Hospital, United Kingdom. Inclusion criteria were younger than 18 years of age and histologically and molecularly confirmed posterior fossa tumors. Subjects with no available preoperative MR imaging and tumors located primarily in the brain stem were excluded. Imaging characteristics of the tumors were evaluated following a predesigned, step-by-step flow chart. Agreement between readers was tested with the Cohen κ, and each diagnosis was analyzed for accuracy. A total of 148 cases were included, with a median age of 3.4 years (interquartile range, 2.1-6.1 years), and a male/female ratio of 1.24. The predesigned flow chart facilitated identification of pilocytic astrocytoma, ependymoma, and medulloblastoma tumors with high sensitivity and specificity. On the basis of the results, the flow chart was adjusted so that it would also be able to better discriminate atypical teratoid/rhabdoid tumors and medulloblastoma groups 3 or 4 (sensitivity = 75%-79%; specificity = 92%-99%). Moreover, our adjusted flow chart was useful in ruling out ependymoma, pilocytic astrocytomas, and medulloblastoma tumors. The modified flow chart offers a structured tool to aid in the adjunct diagnosis of pediatric posterior fossa tumors. Our results also establish a useful starting point for prospective clinical studies and for the development of automated algorithms, which may provide precise and adequate diagnostic tools for these tumors in clinical practice.