MURAGAKI Yoshihiro
   Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine
   Position   Visiting Professor
Language Japanese
Title Preoperative differential diagnosis of grade II and grade III in cases with astrocytoma, IDH mutant
Conference The 39th Annual Meeting of the Japan Society for Neuro-Oncology
Conference Type Nationwide Conferences
Presentation Type Speech
Lecture Type Panelist at Symposium/Workshop (Applied)
Date 2021/12/06
Holding period 2021/12/05~2021/12/07
Society abstract 第39回日本脳腫瘍学会学術集会 プログラム・講演抄録集 84
Summary NI-6 PMC8648256
Purpose: We attempted to differentiate between IDH-mutant astrocytoma Grade II and grade III by using methionine (MET) positron emission tomography (PET) and magnetic resonance spectroscopy (MRS). Subjects and Methods: We retrospectively analyzed 41 adult supratentorial glioma cases with confirmed histological diagnosis and IDH status from June 2015 to June 2020. These included 21 males, with an average age of 38.5 years (19–59 years), including seven astrocytoma grade II (A-II) and 34 grade III (A-III) cases. We determined the accumulation value rate of the maximum tumor to normal cortex accumulation value (T/N ratio) in MET-PET. We obtained the peak ratios of N-acetyl aspartate (NAA)/ creatine (Cr), choline (Cho)/Cr, and Cho/NAA. We investigated the correlation between the T/N ratios and MRS parameters and examined the contrast effects on MRI. Results: There were no significant differences in the T/N ratio and MRS parameters between A-IIs and A-IIIs. Only Cho/NAA ratios were significantly correlated with the T/N ratios (r = 0.443, P = 0.0037). We divided the distribution map into four areas with the highest T/N ratio of AII (1.59) and the highest Cho/NAA ratio (3.66). That is, 1) T/N ratio ≤ 1.59 & Cho/NAA ≤ 3.66, 2) >1.59 & ≤ 3.66, 3) ≤1.59 & > 3.66, 4) &gt 1.59 & &gt 3.66. The diagnostic rates for A-III were 1) 61.1% (11/18), 2) 100% (7/7), 3) 100% (9/9), and 4) 100% (7/7). We found the contrast effects in only 7 cases (20.6%) of A-III, which were distributed in areas 2) to 4). Conclusion: A-IIs and A-IIIs distributed in area 1) were difficult to distinguish, and they need careful observation as a step before the transition to areas 2)-4). Meanwhile, A-IIIs reaching widespread distribution to areas 2)-4) because of their wide range of malignancies require clinically aggressive treatment. The method might be beneficial in grade analysis of IDH-mutant astrocytomas.

Keywords: glioma, methionine PET, MRS