Differentiation of hemangioblastoma from brain metastasis using MR amide proton transfer imaging

Abstract

Background and Purpose: Differentiation between hemangioblastoma and brain metastasis remains a challenge in neuroradiology using conventional MRI. Amide proton transfer (APT) imaging can provide unique molecular information. This study aimed to evaluate the usefulness of APT imaging in differentiating hemangioblastomas from brain metastases and compare APT imaging with diffusion-weighted imaging and dynamic susceptibility contrast perfusion-weighted imaging.Methods: This retrospective study included 11 patients with hemangioblastoma and 20 patients with brain metastases. Region-of-interest analyses were employed to obtain the mean, minimum, and maximum values of APT signal intensity, apparent diffusion coefficient (ADC), and relative cerebral blood volume (rCBV), and these indices were compared between hemangioblastomas and brain metastases using the unpaired t-test and Mann-Whitney U test. Their diagnostic performances were evaluated using receiver operating characteristic (ROC) analysis and area under the ROC curve (AUC). AUCs were compared using DeLong's method.Results: All MRI-derived indices were significantly higher in hemangioblastoma than in brain metastasis. ROC analysis revealed the best performance with APT-related indices (AUC = 1.000), although pairwise comparisons showed no significant difference between the mean ADC and mean rCBV.Conclusions: APT imaging is a useful and robust imaging tool for differentiating hemangioblastoma from metastasis.

Amide proton transfer weighted imaging in pediatric neuro‐oncology: initial experience

“…Histological characteristics of pilocytic astrocytoma, especially microvascular proliferation, possibly explain the high APTw values. This might be similar to adult hemangioblastoma 30 . Furthermore, in essentially all pilocytic astrocytomas, MAPK pathway alterations are found to be the tumor driver, most often KIAA1549‐BRAF (35%), BRAF V600E (17%), or NF1 (17%) 31 .…”

“…Increased blood volume because of enhanced microvascular proliferation and/or mobile proteins leaking from this vasculature may result in high APTw values. 30 APTw values might reduce after bevacizumab treatment since it reduces microvascular proliferation. Treatment effects should be assessed in a longitudinal matter, which is possible since APTw maps are repeatable in cerebral and cerebellar brain regions.…”

“…This might be similar to adult hemangioblastoma. 30 Furthermore, in essentially all pilocytic astrocytomas, MAPK pathway alterations are found to be the tumor driver, most often KIAA1549-BRAF (35%), BRAF V600E (17%), or NF1 (17%). 31 This pathway promotes cell growth and survival and reduces apoptosis.…”

“…For example, effect of bevacizumab, a monoclonal antibody against the vascular endothelial growth factor, 37 can be expected in pilocytic astrocytoma since this type of tumor has enhanced microvascular proliferation. Increased blood volume because of enhanced microvascular proliferation and/or mobile proteins leaking from this vasculature may result in high APTw values 30 . APTw values might reduce after bevacizumab treatment since it reduces microvascular proliferation.…”