Noninvasive Histologic Grading of Solid Astrocytomas Using Proton Magnetic Resonance Spectroscopy

Abstract

Background: Proton magnetic resonance spectroscopy (¹H MRS) constitutes a promising modality to assess intracranial pathology. We present our experience using this method in grading solid brain astrocytomas. Material and Methods: Using a 1.5-Tesla MRI unit, 71 patients with the radiographic diagnosis of astrocytoma were examined. Water-suppressed single-voxel ¹H MRS was employed in all of our patients. The concentrations of choline (Cho), N-acetyl-aspartate (NAA), phosphocreatine-creatine (Pcr-Cr), myo-inositol (MI), lactate (Lac), lipids (Lip) as well as the metabolite ratios of Cho/Pcr-Cr, NAA/PCr-Cr and NAA/Cho were calculated. An appropriate surgical biopsy was performed. Standard pathology examination was employed in a double-blinded fashion. Results: An increased concentration of Cho and decreased concentrations of Pcr-Cr and NAA were detected. The concentrations of Lac, Lip and MI varied inconsistently, even among tumors of the same histologic grade. The Cho/Pcr-Cr ratio was calculated. This ratio was found to be 2.15 ± 0.26 in 27 patients with astrocytomas grade I and II, 2.78 ± 0.09 in 18 patients with grade III, and 5.40 ± 0.16 in 26 patients with grade IV. Discussion: The increased concentration of Cho is due to the increased cellularity and a relatively increased number of membranous structures in highly malignant tumors. In abnormal anaerobic metabolic tumor states there is relatively less phosphorylization of creatine. By using the Cho/Pcr-Cr ratio the concomitant effects of structural and metabolic alteration can thereby be emphasized for diagnostic advantage. Conclusion: The Cho/Pcr-Cr is a very important and statistically significant marker (p = 0.043) determining the degree of intracranial astrocytoma malignancy.

Improved Brain Tumor Classification by Sodium MR Imaging: Prediction ofIDHMutation Status and Tumor Progression

“…For example, tumor grade is associated with relative cerebral blood volume [32][33][34] ; volume transfer coefficient [35][36][37][38] ; apparent diffusion coefficient 39,40 ; and cerebral metabolite ratios, for example, the choline to N-acetylaspartate 33 and the choline to creatine ratios. 33,41 Also, relative cerebral blood volume, 34,[42][43][44][45][46][47][48] volume transfer coefficient, 35,49 apparent diffusion coefficient, 50-52 and metabolite ratios, for example, the choline to Nacetylaspartate ratio, 53 aid prediction of PFS. Moreover, 1 H-MR spectroscopy of 2-hydroxyglutarate enables the detection of IDH mutations.…”

Lactate, choline, and creatine levels measured by vitro 1H‐MRS as prognostic parameters in patients with non‐small‐cell lung cancer

“…Metabolite ratios (particularly Cho levels) have been correlated with Ki-67 levels in gliomas (22). MRS measurements of Cho/Cr and Cho/N-acetyl aspartate (NAA) ratios should therefore be helpful for grading gliomas (23). Thus, the increased Cho peak found in most studies of brain tumors has been attributed to increased membrane synthesis, increased cellularity, or rapid cell turnover.…”

Non‐invasive detection of hippocampal sclerosis: correlation between metabolite alterations detected by 1H‐MRS and neuropathology

“…1 H-MRS has turned out to be an efficient, non-invasive method for lateralizing the affected hemisphere in patients with TLE (1)(2)(3)(4)(5)(6). It has also been revealed to be a promising tool for grading gliomas (7)(8)(9)(10)(11). Here, we have used it as a non-invasive, preoperative tool to assess the degree of hippocampal sclerosis in patients with intractable TLE.…”