Metabolism and regional cerebral blood volume in autoimmune inflammatory demyelinating lesions mimicking malignant gliomas

Abstract

Dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) and MR spectroscopy are thought to differentiate tumefactive autoimmune inflammatory demyelinating lesions from glial brain tumours. The aim of this work is to evaluate whether regional cerebral blood volume (rCBV), as well as choline (Cho), N-acetyl-aspartate (NAA) and myo-inositol (mIns) concentrations differ between tumefactive lesions and World Health Organization (WHO) grade II-III gliomas. Five patients with single autoimmune inflammatory demyelinating lesions and nine patients with WHO grade II and III gliomas were examined by DSC-MRI and by two-dimensional (2D) 1H MR spectroscopic imaging (1H-MRSI). rCBV values and metabolite concentrations were normalised to the respective values of the contralateral hemisphere. Normalised rCBV in the tumefactive lesions (mean 2.89, range 1.98-6.74) was in the some high level as in gliomas (mean 2.77, range 1.43-6.22). 1H-MRSI revealed increased normalised choline concentrations in five of six examinations of autoimmune lesions (mean 1.4, range 1.06-1.8) and in eight of nine gliomas (mean 1.35, range 0.92-1.73). Tumefactive autoimmune inflammatory demyelinating lesions not only have imaging appearance of gliomas but may also imitate marked increase of rCBV and Cho in WHO grade II-III gliomas.

Commentary: Tumefactive Demyelinating Lesions as a First Clinical Event: Clinical, Imaging, and Follow-up Observations

“…These venular enhancements are usually attributed to dilated venules draining toward distended subependymal veins (4). Enlarged blood vessels with surrounding edema and relative axonal preservation were observed also at histological examination (3, 5). Moreover, some clinical symptoms, more frequent in TDLs than in MS, such as encephalopathy, confusion, rapid memory dysfunction, seizures, stupor/coma (4, 5), and even increased intracranial pressure symptoms (1), are more compatible with venous stasis than with localized and well-defined demyelinating lesions.…”

“…Although some radiological characteristics on routine magnetic resonance imaging (MRI) such as an open-ring enhancement, T2-hypointense rim, peripheral restriction on diffusion-weighted imaging, and venular enhancement are considered typical for TDLs, they were not found in all cases (1–5). Even the advanced MRI techniques, such as MR spectroscopy, led to equivocal results because both normalized choline increase and N -acetyl-aspartate decrease were found in variable proportion in both TDLs (3, 4) and gliomas (3) with a broad overlap between these diseases. Furthermore, the relative cerebral blood volume on dynamic contrast-enhanced MRI, normalized to the respective values of the contralateral hemisphere, has been found higher in gliomas compared to TDLs (6), as well as similarly increased in both pathologies (3).…”

“…Even the advanced MRI techniques, such as MR spectroscopy, led to equivocal results because both normalized choline increase and N -acetyl-aspartate decrease were found in variable proportion in both TDLs (3, 4) and gliomas (3) with a broad overlap between these diseases. Furthermore, the relative cerebral blood volume on dynamic contrast-enhanced MRI, normalized to the respective values of the contralateral hemisphere, has been found higher in gliomas compared to TDLs (6), as well as similarly increased in both pathologies (3). …”

MR Spectroscopic Imaging

“…4a). On the other hand, high tCho signals may be found in pilocytic astrocytomas (Porto et al 2010), acute brain diseases with high cell membrane turnover like encephalitis, acute demyelinating diseases (Blasel et al 2011a), active dysmyelination, tuberculosis, and acute radiation injury. Further, lipid signals and lactate are frequently described as tumor metabolites.…”

Neuroradiological Viewpoint on the Diagnostics of Space-Occupying Brain Lesions

“…High cho and (almost) normal NAA levels with a slight increase in rCBV indicate demyelinating inflammation, such as MS or ADeM [45]. However, both MRSi and MR perfusion may occasionally reveal tumor-like spectra and marked rcBv increases [46]. Diffusion can be restricted in the acute stage of the disease with correspondingly lower ADc values.…”