Preoperative 11 C-Methionine PET-MRI in Pediatric Infratentorial Tumors.

PURPOSE: MRI is the main imaging modality for pediatric brain tumors, but amino acid PET can provide additional information. Simultaneous PET-MRI acquisition allows to fully assess the tumor and lower the radiation exposure. Although symptomatic posterior fossa tumors are typically resected, the patient management is evolving and will benefit from an improved preoperative tumor characterization. We aimed to explore, in children with newly diagnosed posterior fossa tumor, the complementarity of the information provided by amino acid PET and MRI parameters and the correlation to histopathological results. PATIENTS AND METHODS: Children with a newly diagnosed posterior fossa tumor prospectively underwent a preoperative 11 C-methionine (MET) PET-MRI. Images were assessed visually and semiquantitatively. Using correlation, minimum apparent diffusion coefficient (ADC min ) and contrast enhancement were compared with MET SUV max . The diameter of the enhancing lesions was compared with metabolic tumoral volume. Lesions were classified according to the 2021 World Health Organization (WHO) classification. RESULTS: Ten children were included 4 pilocytic astrocytomas, 2 medulloblastomas, 1 ganglioglioma, 1 central nervous system embryonal tumor, and 1 schwannoma. All lesions showed visually increased MET uptake. A negative moderate correlation was found between ADC min and SUV max values ( r = -0.39). Mean SUV max was 3.8 (range, 3.3-4.2) in WHO grade 4 versus 2.5 (range, 1.7-3.0) in WHO grade 1 lesions. A positive moderate correlation was found between metabolic tumoral volume and diameter values ( r = 0.34). There was no correlation between SUV max and contrast enhancement intensity ( r = -0.15). CONCLUSIONS: Preoperative 11 C-MET PET and MRI could provide complementary information to characterize pediatric infratentorial tumors.

Risk factors for intraoperative allogeneic blood transfusion during craniotomy for brain tumor removal in children.

BACKGROUND: Several clinical and surgical factors can influence the occurrence of allogeneic blood transfusion (ABT) during oncologic neurosurgery. OBJECTIVES: To identify the potential predictive factors of ABT during craniotomy for the removal of brain tumors in children and the potential impact of intraoperative ABT on early postoperative outcome. METHODS: A retrospective study was performed in all pediatric patients younger than 18 years who underwent craniotomy for brain tumor removal from December 2009 to December 2012 in our institution. Pre-, intra-, and postoperative data were collected from medical and stored electronic anesthesia records. The predictors of intraoperative ABT were determined using multivariate logistic regression. RESULTS: A total of 110 patients were included. Twenty-seven patients (25%) received intraoperative ABT with a volume of 16 ± 8 ml·kg(-1) . On multivariate analysis, an age <4 years, a duration of surgery >270 min, and a preoperative hemoglobin <12.2 g·dl(-1) were independently associated with the need for intraoperative ABT. We did not show any significant difference concerning postoperative early outcome and length of stay between the transfused and non-transfused patients except for the duration of postoperative mechanical ventilation that was significantly higher in the transfused group (P = 0.04). CONCLUSION: In children, craniotomy for brain tumor removal is at risk of intraoperative ABT. An age <4 years, a duration of surgery >270 min, and a preoperative hemoglobin <12.2 g·dl(-1) are the main factors associated with intraoperative ABT during this surgery.