Yukitomo Ishi1, Shigeru Yamaguchi2, Michiharu Yoshida3, Hiroaki Motegi4, Hiroyuki Kobayashi5, Shunsuke Terasaka6, Kiyohiro Houkin7. 1. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: nekozamurai@me.com. 2. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: yama-shu@med.hokudai.ac.jp. 3. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: michi511leo@yahoo.co.jp. 4. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: moccihiro@yahoo.co.jp. 5. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: hiro-ko@med.hokudai.ac.jp. 6. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: terasas@med.hokudai.ac.jp. 7. Department of neurosurgery, Hokkaido university school of medicine, North 15 West 7, 060-8638 Kita-Ku, Sapporo, Japan. Electronic address: houkin@med.hokudai.ac.jp.
Abstract
BACKGROUND AND PURPOSE: Most individuals with optic pathway/hypothalamic pilocytic astrocytoma (OPHPA) harbor either the BRAF V600E mutation or KIAA1549-BRAF fusion (K-B). This study aimed to investigate the imaging characteristics of OPHPA in relation to BRAF alteration status. MATERIALS AND METHODS: Seven cases of OPHPA harboring either the BRAF V600E mutation or K-B fusion were included in the study. Preoperative magnetic resonance imaging (MRI) was assessed for degree of T2 hyperintensity on T2-weighted images (T2WI) and the ratio of nonenhancing T2 or fluid-attenuated inversion recovery (FLAIR) hyperintense area to the contrast enhanced area (CE) on gadolinium-enhanced-T1 weighted images (T2/FLAIR-CE mismatch). The T2 signal intensity was normalized to cerebrospinal fluid (T2/CSF) for both the V600E and K-B group and compared. T2/FLAIR-CE mismatch was assessed by calculating the proportion of the tumor volume of nonenhancing high T2 signal intensity to the whole lesion (nonenhancing and enhancing components). RESULTS: Four and three cases of OPHPA harboring the BRAF V600E mutation and K-B, respectively, were analyzed. The T2/CSF value was higher in the K-B group than in the V600E group. Moreover, the V600E group had a larger T2/FLAIR-CE mismatch than the K-B group. CONCLUSIONS: The BRAF alteration status in individuals with OPHPA was associated with preoperative MRI by focusing on T2 signal intensity and T2/FLAIR-CE mismatch. The BRAF V600E mutation was associated with a lower T2/CSF value and larger T2/FLAIR-CE mismatch, whereas K-B fusion was associated with a higher T2/CSF value and smaller T2/FLAIR-CE mismatch.
BACKGROUND AND PURPOSE: Most individuals with optic pathway/hypothalamic pilocytic astrocytoma (OPHPA) harbor either the BRAF V600E mutation or KIAA1549-BRAF fusion (K-B). This study aimed to investigate the imaging characteristics of OPHPA in relation to BRAF alteration status. MATERIALS AND METHODS: Seven cases of OPHPA harboring either the BRAF V600E mutation or K-B fusion were included in the study. Preoperative magnetic resonance imaging (MRI) was assessed for degree of T2 hyperintensity on T2-weighted images (T2WI) and the ratio of nonenhancing T2 or fluid-attenuated inversion recovery (FLAIR) hyperintense area to the contrast enhanced area (CE) on gadolinium-enhanced-T1 weighted images (T2/FLAIR-CE mismatch). The T2 signal intensity was normalized to cerebrospinal fluid (T2/CSF) for both the V600E and K-B group and compared. T2/FLAIR-CE mismatch was assessed by calculating the proportion of the tumor volume of nonenhancing high T2 signal intensity to the whole lesion (nonenhancing and enhancing components). RESULTS: Four and three cases of OPHPA harboring the BRAF V600E mutation and K-B, respectively, were analyzed. The T2/CSF value was higher in the K-B group than in the V600E group. Moreover, the V600E group had a larger T2/FLAIR-CE mismatch than the K-B group. CONCLUSIONS: The BRAF alteration status in individuals with OPHPA was associated with preoperative MRI by focusing on T2 signal intensity and T2/FLAIR-CE mismatch. The BRAF V600E mutation was associated with a lower T2/CSF value and larger T2/FLAIR-CE mismatch, whereas K-B fusion was associated with a higher T2/CSF value and smaller T2/FLAIR-CE mismatch.
Authors: A Trasolini; C Erker; S Cheng; C Crowell; K McFadden; R Moineddin; M A Sargent; D Mata-Mbemba Journal: AJNR Am J Neuroradiol Date: 2022-07-21 Impact factor: 4.966