Advanced MR Imaging Techniques in the Diagnosis of Intraaxial Brain Tumors in Adults

Abstract

Intraaxial brain masses are a significant health problem and present several imaging challenges. The role of imaging is no longer limited to merely providing anatomic details. Sophisticated magnetic resonance (MR) imaging techniques allow insight into such processes as the freedom of water molecule movement, the microvascular integrity and hemodynamic characteristics, and the chemical makeup of certain compounds of masses. The role of the most commonly used advanced MR imaging techniques-perfusion imaging, diffusion-weighted imaging, and MR spectroscopy-in the diagnosis and classification of the most common intraaxial brain tumors in adults is explored. These lesions include primary neoplasms (high- and low-grade), secondary (meta-static) neoplasms, lymphoma, tumefactive demyelinating lesions, abscesses, and encephalitis. Application of a diagnostic algorithm that integrates advanced MR imaging features with conventional MR imaging findings may help the practicing radiologist make a more specific diagnosis for an intraaxial tumor.

Application of magnetic resonance spectroscopy in the differentiation of high-grade brain neoplasm and inflammatory brain lesions

“…NAA is found in normal neurons and when altered, reductions occur both in tumors and in inflammatory lesions thereby indicating neuronal loss. The NAA/Cr ratio has discriminatory value when analyzed together with the Cho/Cr ratio increasing the specificity of the method 10 .…”

Neuroimaging in Neuro-Oncology

“…There are concerted efforts to combine all the anatomic and physiologic MRI techniques described in this review in a multiparametric, algorithmic fashion, in order to rapidly incorporate them into the clinical practice of neuroimaging and to benefit patients with brain tumor. 49,50 Despite a potentially powerful role in advancing knowledge of brain tumor biology, physiologybased MRI methods still await much-needed validation and correlation with clinical outcome to determine whether (and if so, how) they may become a critical and indispensable part of clinical management of patients with brain tumor.…”

Clinical Application of MR Spectroscopy and Imaging of Brain Tumor

“…Maps of apparent diŠusion coe‹cient (ADC), fractional anisotropy (FA), and regional cerebral blood volume (rCBV) as wells as 1 H-MRS generated by advanced techniques aid speciˆcation of brain tumors. 1,2 Use of scanners with high magneticˆeld has improved image quality of MRS and increased its role in the diagnosis and management of intracranial tumors. 1 H-MRS can provide metabolic information, including that regarding tissue activity or brain damage correlating with pathological changes.…”

“…1,2 Use of scanners with high magneticˆeld has improved image quality of MRS and increased its role in the diagnosis and management of intracranial tumors. 1 H-MRS can provide metabolic information, including that regarding tissue activity or brain damage correlating with pathological changes. High choline (Cho) and low N-acetylaspartate (NAA) peaks show tumor aggressiveness, and other metabolic peaks such as lipid (Lip) or lactate (Lac) can also show necrosis in tumor.…”