Proton Magnetic Resonance Spectroscopic Imaging in Children With Recurrent Primary Brain Tumors

Abstract

The maximum tumor Cho:NAA ratio seems to be predictive of outcome in children with recurrent primary brain tumors and should be evaluated as a prognostic indicator in newly diagnosed childhood brain tumors.

Pediatric Brain Tumors: Magnetic Resonance Spectroscopic Imaging

“…A number of studies suggest that proton MRS spectroscopy promises an early prediction of whether a lesion has responded to therapy (Byrd et al, 1996a;Lazareff et al, 1998;Warren et al, 2000;Tzika et al, 2001;Tarnawski et al, 2002;Tzika et al, 2004). In a study involving 75 children with brain tumors, Byrd et al, found elevated Cho and elevated lactate and or lipids (Byrd et al, 1996a), which agrees with our data and data in adults.…”

“…Although elevated Cho and low NAA before therapy may be a reliable indicator of pediatric brain tumor malignancy (Sutton et al, 1992;Tzika et al, 1993b;Tzika, 1995;Byrd et al, 1996b;Tzika et al, 1996a;Tzika et al, 1997;Taylor et al, 1998;Tzika et al, 2004), the consensus is that proton MR spectroscopy results may not be used alone to classify tumors, as some studies have shown considerable overlap in proton MRSI results among different tumor types (Warren et al, 2000;Warren, 2004). In our experience, the different MR spectral patterns may suggest that proton MRSI can be used to distinguish at least three different tissue compartments -normal, tumor, and necrosis- (Naidich, 1995;Tzika et al, 1997), whereas mixed MR spectral patterns were due to the known heterogeneity of tumors, as confirmed by the histopathologic features (Tzika et al, 2002).…”

“…Another study involving 11 pediatric patients with low-grade gliomas, the tumors that progressed during a 2-year period displayed higher normalized Cho than those that remained stable (Lazareff et al, 1998). Warren et al, found in 27 children with recurrent or progressive tumors that the maximum tumor Cho:NAA ratio was predictive of outcome; Cho:NAA greater than 4.5 correpsonded to survival time of 22 weeks and all 13 patients died by 63 weeks; Cho:NAA less or equal to 4.5 corresponded to more than 50% survival at 63 weeks (Warren et al, 2000). Since proton MR spectroscopy detects total creatine (creatine, phosphocreatine; tCr) in addition to Cho and NAA in tumors, we hypothesized that we might be able to use proton MRSI to measure tCr to predict treatment response of pediatric brain tumors.…”

“…Localized MR spectroscopy studies in children are increasing (Tzika et al, 1993a;Lazareff et al, 1996;Tzika et al, 1997;Lazareff et al, 1998;Lazareff et al, 1999;Warren et al, 2000;Tzika et al, 2001;Tzika et al, 2002;Tzika et al, 2003;Astrakas et al, 2004;Tzika et al, 2004). Brain tumors are usually heterogeneous and complicated by edema and necrosis of the adjacent brain parenchyma, yet their spectra are critically impacted by precision in voxel size and position.…”

Advances in treatment of pediatric brain tumors

“…In the management of brain tumors, MRS is most valuable in the evaluation of whether MRI changes represent treatment-related effects or recurrent disease; it may also prove useful in the assessment of tumor response to therapy. 5 Diffusion-weighted MRI. The use of diffusionweighted MRI is currently being explored to identify parameters of tissue change at a cellular level that might help predict tumor response to therapy.…”