Role of MR Spectroscopy in Evaluation of Posterior Fossa Tumors in Children

This study aims to go over the most common tumors of posterior fossa affecting children, with emphasis on their Magnetic Resonance Imaging “MRI” findings and Magnetic Resonance “MR” Spectroscopy, to improve histological approach in imaging, helping the management and approach for surgeons in providing information to the patients’ parents. It was a prospective study carried out on 20 patients with posterior fossa tumors. The patients were referred to Radiology Department of AL-Zahraa University Hospital for MRI and MR Spectroscopy examination after getting approval from ethical committee. A written informed consent was taken from parents. This study was conducted for a period of six months from May 2021 to October 2021. 20 patients ages ranged 3-14 years. Eight were males and twelve were females. Incidence of pilocytic astrocytoma 8 cases (40%), ependymoma 6 cases (30%), medulloblastoma 4 cases (20%) and atypical teratoid rhabdoid tumor 2 cases (10%). Their distribution in the posterior cranial fossa was 2 cases at the pons (10%), 4 cases at the cerebellum (20%), 10 cases at the fourth ventricle (50%), 2 cases at the midline posterior fossa (10%) and 2 cases at the CPA (10%). Different metabolite peaks were evaluated from resulting MR spectra, including choline, NAA, creatine, lipid, lactate, myoinositol and taurine peaks. Metabolite ratios, such as Cho/Cr and Cho/NAA ratios, were used for diagnosis and differentiation of different tumor types. We concluded MR spectroscopy is a powerful tool in diagnosis of posterior fossa tumors in pediatric patients and determination of tumor grades because it enables biochemical assessment of tumor dynamics.