AB006. The use of magnetic resonance spectroscopy in the differential diagnosis of paediatric intracranial tumours

Background: Despite different intracranial tumour subtypes varying largely in their prognoses and recommended treatment regimens, they can have markedly similar appearances on standard radiology, especially in paediatric patients where they tend to occur in the midline. There is a need for a non-invasive, accurate method of determining tumour diagnosis to help expedite treatment planning. Existing studies have found magnetic resonance spectroscopy (MRS) to have value in diagnosing intracranial tumours in adults. The aim of this study was to investigate whether MRS could be accurate in diagnosing and grading paediatric intracranial tumours.

Methods: The hospital database was retrospectively searched for paediatric intracranial tumour patients ≤18 years that had 1.5 T MRS data available. Medical and demographic data were collected from existing records including MRS metabolites N-acetylaspartate (NAA), creatine (Cr), and choline (Cho), and final histopathologic diagnosis. MRS metabolites were then statistically compared against final histopathologic diagnosis.

Results: In total, 166 patients were included. In the overall cohort, the tumour to control tissue Cr ratio was significantly higher in grade 1 than grade 4 tumours (P=0.03), and tumour Cho/Cr was significantly higher in grade 4 than grade 1 tumours (P=0.004). When analyzing tumour subtypes, control tissue Cr was significantly higher in embryonal/germ cell tumours than glial tumours (P=0.044). Binary logistic regression models including MRS metabolite ratios and age, sex, and tumour location covariates could diagnose grade 4 tumours [area under the curve (AUC) =0.857], and grade 1 tumours (AUC =0.766) with reasonable accuracy.

Conclusions: This study suggests that MRS has benefits in the non-invasive diagnosis of paediatric intracranial tumours, in particular, identifying low- and high-grade tumours. Future advances in MRS technology, and larger cross-sectional studies will be necessary to improve the clinical integration of MRS for accurate non-invasive paediatric intracranial tumour diagnosis.

Keywords: Magnetic resonance spectroscopy (MRS); intracranial tumours; neuro-oncology; paediatrics