Magnetic resonance spectroscopy of atypical diffuse pontine masses

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Diffuse pontine gliomas in children carry a dismal prognosis, with a mean survival of less than 1 year despite therapy. The diagnosis is based on the characteristic changes demonstrated on traditional magnetic resonance (MR) imaging. A few typically MR imaging–appearing pontine masses, however, do not behave in the expected fashion, which calls the original diagnosis into question.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors conducted a retrospective review of data obtained in 42 children (age 6 months–13 years) in whom diffuse pontine glioma had been diagnosed at their institution. Five of these patients (12%) survived longer than expected (&gt; 8 months). There were no differences in these patients in terms of demographics, presentation, traditional imaging findings, or treatment compared with the group as a whole. Magnetic resonance spectroscopy, however, demonstrated two distinct patterns not seen in typical diffuse pontine gliomas. In two patients elevated lipid and lactate levels were shown, with decreased levels of choline, myoinositol, and <jats:sc>n</jats:sc>-acetyl-aspartate (NAA). In the other patients strikingly elevated choline/creatinine ratios and myoinositol levels were observed in comparison with typical pontine tumors.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>These MR spectroscopy patterns demonstrated in this retrospective study seem to convey prognostic information and may lead to an expansion of this diagnostic tool.</jats:p></jats:sec>

Proton magnetic resonance spectroscopy predicts survival in children with diffuse intrinsic pontine glioma

“…Our study included 6 patients (16%) whose overall survival was > 24 mo. This represents a larger proportion of long-term survivors when compared some studies [6], but is comparable to other cohorts reported in the literature [31, 52]. The majority of patients were referred to our institution following radiation therapy for evaluation after disease progression.…”

Results of positron emission tomography guidance and reassessment of the utility of and indications for stereotactic biopsy in children with infiltrative brainstem tumors

“…24 The evaluation of the prognostic value of PET data in intrinsic infiltrative brainstem lesions will require a larger and more homogeneous series. Indeed, the authors of a study conducted in a large series of patients have recently suggested that MR spectroscopy data might provide significant prognostic information in intrinsic infiltrative brainstem lesions, 13 contrary to MR contrast enhancement, which seems to present a very limited prognostic value in brainstem gliomas. 12 In our series, MR contrast enhancement was not correlated with FDG uptake level or extent.…”

“…2,6,7,10,21,[25][26][27][28] Therefore, the management of these lesions requires careful consideration of the risk related to serial biopsy trajectories and the level of radiological diagnostic certainty. 7,12,13,26 It is common, however, to encounter intrinsic infiltrative brainstem lesions that cannot be diagnosed on the basis of imaging studies alone; the preoperative neuroimaging diagnosis may not be accurate for tumor type in approximately Results of positron emission tomography guidance and reassessment of the utility of and indications for stereotactic biopsy in children with infiltrative brainstem tumors 25%, and up to 13% of such lesions are nonneoplastic ones. 13,27,28 Therefore, the consequences of empirical therapy should not be underestimated before making appropriate treatment recommendations.…”

“…7,12,13,26 It is common, however, to encounter intrinsic infiltrative brainstem lesions that cannot be diagnosed on the basis of imaging studies alone; the preoperative neuroimaging diagnosis may not be accurate for tumor type in approximately Results of positron emission tomography guidance and reassessment of the utility of and indications for stereotactic biopsy in children with infiltrative brainstem tumors 25%, and up to 13% of such lesions are nonneoplastic ones. 13,27,28 Therefore, the consequences of empirical therapy should not be underestimated before making appropriate treatment recommendations. Actually, in many centers a stereotactic biopsy procedure is still performed whenever possible, with estimates of low and acceptable combined surgical morbidity/mortality rates of 0.7 to 3% and 3 to 5%, respectively.…”

Safety and efficacy of brainstem biopsy in children and young adults

“…34 In this context, and particularly given the possibility of a nonneoplastic diagnosis, the standard practice of empirical radiation therapy has been questioned. 29,[35][36][37] Aside from the need for diagnostic certainty, there has been increased recognition that tissue samples will be needed for the development and testing of cutting-edge treatment options, including new chemotherapies, gene therapies, and immunotherapies. 25,38 New treatments are especially necessary for patients with DIPG for whom meaningful therapeutic options are limited, and some have argued that progress has been impeded by the lack of available tissue for analysis.…”