ABSTRACT
Our purpose was to investigate whether in vivo proton magnetic resonance spectroscopic imaging, using normalized concentrations of total choline (tCho) and total creatine (tCr), can differentiate between WHO grade I pilocytic astrocytoma (PA) and diffuse, fibrillary WHO grade II astrocytoma (DA) in children. Data from 16 children with astrocytomas (11 children with PA and 5 children with DA) were evaluated retrospectively. MRS was performed before treatment in all patients with histologically proven low-grade astrocytomas. Metabolite concentrations of tCho and tCr were normalized to the respective concentration in contralateral brain tissue. The Mann-Whitney U test was performed to evaluate differences between these two groups. Normalized tCho did not show any statistically significant difference between the two groups. There was a strong trend (P = 0.07) toward higher values of normalized tCr in the DA group. For 3 of 5 children with DA, lactate was detectable, but only 1 of 11 children with PA showed lactate. We concluded that choline as a single parameter is not reliable in the differential diagnosis of low-grade astrocytomas in children. Our results suggest that tCr concentrations combined with lactate will be helpful in the differential diagnosis of PA and DA in children.
Subject(s)
Brain Neoplasms/pathology , Glioma/pathology , Magnetic Resonance Imaging/methods , Adolescent , Astrocytoma/diagnosis , Astrocytoma/metabolism , Astrocytoma/pathology , Brain/pathology , Brain Neoplasms/diagnosis , Brain Neoplasms/metabolism , Child , Child, Preschool , Choline/metabolism , Creatine/metabolism , Diagnosis, Differential , Female , Glioma/diagnosis , Glioma/metabolism , Humans , Infant , Infratentorial Neoplasms/metabolism , Infratentorial Neoplasms/pathology , Magnetic Resonance Spectroscopy , Male , Supratentorial Neoplasms/metabolism , Supratentorial Neoplasms/pathologyABSTRACT
OBJECTIVE: Pilocytic astrocytomas may show heterogeneous histopathological and imaging features which are commonly attributed to malignant gliomas. Using magnetic resonance (MR) spectroscopy, we assessed if pilocytic astrocytomas show increased choline (tCho), classically related to proliferation and malignancy of gliomas. METHODS: Sixteen patients (five adults, age 20-55 years and 11 children, age 6 months-15 years) with histologically proven pilocytic astrocytomas were evaluated retrospectively. MR spectroscopy was performed prior to surgery or biopsy in all patients. Intensities of tCho and total creatine (tCr) signals were normalised to the respective signal intensity of contralateral brain tissue and statistically evaluated for group differences between adults and children. RESULTS: The tCho levels covered a wide range with a trend towards elevated values, especially in the adult group. tCho levels ranged from 0.78 to 2.92 in the paediatric group (mean 1.15) and from 1.15 to 3.03 in the adult group (mean 1.35). Diminished or normal tCr values were observed in all patients but one. CONCLUSIONS: The well-known positive correlation between increase of tCho and the grade of gliomas seems to be violated by WHO grade I pilocytic astrocytomas showing a wide range of tCho values with an even marked increase in some cases. No significant differences have been identified in the MR spectroscopy metabolite profiles between paediatric and adult pilocytic astrocytomas.
