Multimodal MR Imaging (Diffusion, Perfusion, and Spectroscopy): Is It Possible to Distinguish Oligodendroglial Tumor Grade and 1p/19q Codeletion in the Pretherapeutic Diagnosis?

Abstract

BACKGROUND AND PURPOSE:Pretherapeutic determination of tumor grade and genotype in grade II and III oligodendroglial tumors is clinically important but is still challenging. Tumor grade and 1p/19q status are currently the 2 most important factors in therapeutic decision making for patients with these tumors. Histopathology and cMRI studies are still limited in some cases. In the present study, we were interested in determining whether the combination of PWI, DWI, and MR spectroscopy could help distinguish oligodendroglial tumors according to their histopathologic grade and genotype.

Perfusion and diffusion MRI signatures in histologic and genetic subtypes of WHO grade II–III diffuse gliomas

“…Consistent with previous studies, we observed significant differences in diffusion MR measurements between 1p/19q co-deleted tumors from non-1p/19q co-deleted tumors [22][23][24][25] and IDH1 mutant from IDH1 wild-type diffuse gliomas [26]. Our findings did not appear to corroborate those of Tan et al [26], who reported a significantly higher rCBV in IDH WT compared with IDH MUT gliomas, though differences may stem from our smaller sample size as well as our more conservative statistical methods.…”

“…Similarly, Lev et al [21] observed a higher maximum rCBV in oligodendrogliomas compared with astrocytomas in a similar sized cohort of patients (N = 30; 8 oligodendrogliomas; 4 WHO II and 4 WHO III) even after leakage correction; however, the relatively low number of patients and use of maximum rCBV measurements likely biased their results toward more corticallybased lesions or tumors near vascular structures. Lastly, our current results demonstrated no difference in median ADC between histologic subtypes, which corroborate the findings by Fellah et al [22], but are inconsistent with the findings from Bian et al [34], who found a lower ADC in oligodendrogliomas compared with astrocytomas. Some of the differences may have stemmed from our smaller sample size in grade II gliomas and the differences in criteria used for distinguishing oligoastrocytomas from oligodendrogliomas and astrocytomas.…”

“…Several studies have illustrated differences in diffusion and perfusion MR measurements between oligodendrogliomas from astrocytomas [20,21], 1p/19q co-deleted tumors (1p19q − ) from non-1p/19q co-deleted tumors (1p19q + ) [22][23][24][25], and IDH mutant (IDH MUT ) from IDH wild-type (IDH WT ) diffuse gliomas [26]. Presumably, these observed differences in diffusion MR measurements of apparent diffusion coefficient (ADC) and perfusion MR imaging measurements of relative cerebral blood volume (rCBV) between subtypes reflects known differences in tumor cell morphometry and aspects of vascular biology [27].…”

3D Pseudocontinuous Arterial Spin-Labeling MR Imaging in the Preoperative Evaluation of Gliomas

“…These results conflicted with those of a previous study based on CASL-derived CBF max . 12 However, a recent study by Fellah et al, 28 based on DSC-derived relative CBF, reported a result similar to that in our study. Several previous studies have also shown a significantly higher relative CBV in anaplastic oligodendrogliomas than in oligodendrogliomas, [28][29][30][31] while some other studies have reported a conflicting result.…”

Genetically Defined Oligodendroglioma Is Characterized by Indistinct Tumor Borders at MRI

“…[23][24][25] Provided that these techniques, particularly spectroscopy, continue to advance at their present rate, radiographic identification of 1p/19q status could be all that is necessary to categorize WHO grade II and III infiltrating gliomas by imaging. 18,[26][27][28][29] Our finding of an association between lower ADC values with 1p/19q codeletion has previously been described in small studies. 16,30 Further investigation will be necessary to define the optimal way of measuring ADC and to determine the physiologic correlate of ADC values in genetically defined oligodendroglioma.…”