Exploratory evaluation of MR permeability with 18F-FDG PET mapping in pediatric brain tumors: A report from the pediatric brain tumor consortium

Katherine A. Zukotynski, Frederic H. Fahey, Sridhar Vajapeyam, Sarah S. Ng, Mehmet Kocak, Sridharan Gururangan, Larry E. Kun, Tina Y. Poussaint

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16 Scopus citations

Abstract

The purpose of this study was to develop a method of registering 18F-FDG PET with MR permeability images for investigating the correlation of 18F-FDG uptake, permeability, and cerebral blood volume (CBV) in children with pediatric brain tumors and their relationship with outcome. Methods: Twenty-four children with brain tumors in a phase II study of bevacizumab and irinotecan underwent brain MR and 18F-FDG PET within 2 wk. Tumor types included supratentorial high-grade astrocytoma (n = 7), low-grade glioma (n = 9), brain stem glioma (n = 4), medulloblastoma (n = 2), and ependymoma (n = 2). There were 33 cases (pretreatment only [n = 12], posttreatment only [n = 3], and both pretreatment [n = 9] and posttreatment [n = 9]). 18F-FDG PET images were registered to MR images from the last time point of the T1 perfusion time series using mutual information. Three-dimensional regions of interest (ROIs) drawn on permeability images were automatically transferred to registered PET images. The quality of ROI registration was graded (1, excellent; 2, very good; 3, good; 4, fair; and 5, poor) by 3 independent experts. Spearman rank correlations were used to assess correlation of maximum tumor permeability (Kpsmax), maximum CBV (CBVmax), and maximum 18F-FDG uptake normalized to white matter (T/Wmax). Cox proportional hazards models were used to investigate associations of these parameters with progressionfree survival (PFS). Results: The quality of ROI registration between PET and MR was good to excellent in 31 of 33 cases. There was no correlation of baseline Kps max with CBVmax (Spearman rank correlation50.018 [P50.94]) or T/Wmax (Spearman rank correlation50.07 [P = 0.76]). Baseline CBVmax was correlated with T/Wmax (Spearman rank correlation = 0.47 [P = 0.036]). Baseline Kpsmax, CBVmax, and T/Wmax were not significantly associated with PFS (P = 0.42, hazard ratio [HR] 5 0.97, 95% confidence interval [CI] 5 0.90-1.045, and number of events [nevents] 5 15 for Kpsmax; P = 0.41, HR 5 0.989, 95% CI 5 0.963-1.015, and nevents 5 14 for CBVmax; and P = 0.17, HR 5 1.49, 95% CI 5 0.856-2.378, and nevents 5 15 for T/Wmax). Conclusion: 18F-FDG PET and MR permeability images were successfully registered and compared across a spectrum of pediatric brain tumors. The lack of correlation between metabolism and permeability may be expected because these parameters characterize different molecular processes. The correlation of CBV and tumor metabolism may be related to an association with tumor grade. More patients are needed for a covariate analysis of these parameters and PFS by tumor histology. COPYRIGHT

Original languageEnglish (US)
Pages (from-to)1237-1243
Number of pages7
JournalJournal of Nuclear Medicine
Volume54
Issue number8
DOIs
StatePublished - Aug 1 2013

Keywords

  • Brain tumor
  • Cerebral blood volume
  • F-FDG PET
  • MR permeability
  • Pediatric

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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    Zukotynski, K. A., Fahey, F. H., Vajapeyam, S., Ng, S. S., Kocak, M., Gururangan, S., Kun, L. E., & Poussaint, T. Y. (2013). Exploratory evaluation of MR permeability with 18F-FDG PET mapping in pediatric brain tumors: A report from the pediatric brain tumor consortium. Journal of Nuclear Medicine, 54(8), 1237-1243. https://doi.org/10.2967/jnumed.112.115782