Chemical Exchange Saturation Transfer and Amide Proton Transfer Imaging

Bioimaging ◽  
2020 ◽  
pp. 101-120
Author(s):  
Takashi Yoshiura
Keyword(s):  
Proton Transfer ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Amide Proton ◽  
Saturation Transfer ◽  
Amide Proton Transfer ◽  
Amide Proton Transfer Imaging

Amide proton transfer imaging for differentiation of tuberculomas from high-grade gliomas: Preliminary experience

2021 ◽  
pp. 197140092110027
Author(s):  
Karthik Kulanthaivelu ◽  
Shumyla Jabeen ◽  
Jitender Saini ◽  
Sanita Raju ◽  
Atchayaram Nalini ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Chemical Exchange ◽  
Spin Echo ◽  
Chemical Exchange Saturation Transfer ◽  
Amide Proton ◽  
High Grade ◽  
Saturation Pulse ◽  
Amide Proton Transfer ◽  
High Grade Gliomas ◽  
Amide Protons

Purpose Tuberculomas can occasionally masquerade as high-grade gliomas (HGG). Evidence from magnetisation transfer (MT) imaging suggests that there is lower protein content in the tuberculoma microenvironment. Building on the principles of chemical exchange saturation transfer and MT, amide proton transfer (APT) imaging generates tissue contrast as a function of the mobile amide protons in tissue’s native peptides and intracellular proteins. This study aimed to further the understanding of tuberculomas using APT and to compare it with HGG. Method Twenty-two patients ( n = 8 tuberculoma; n = 14 HGG) were included in the study. APT was a 3D turbo spin-echo Dixon sequence with inbuilt B0 correction. A two-second, 2 μT saturation pulse alternating over transmit channels was applied at ±3.5 ppm around water resonance. The APT-weighted image (APTw) was computed as the MT ratio asymmetry (MTRasym) at 3.5 ppm. Mean MTRasym values in regions of interest (areas = 9 mm2; positioned in component with homogeneous enhancement/least apparent diffusion coefficient) were used for the analysis. Results MTRasym values of tuberculomas ( n = 14; 8 cases) ranged from 1.34% to 3.11% ( M = 2.32 ± 0.50). HGG ( n = 17;14 cases) showed MTRasym ranging from 2.40% to 5.70% ( M = 4.32 ± 0.84). The inter-group difference in MTRasym was statistically significant ( p < 0.001). APTw images in tuberculomas were notable for high MTRasym values in the perilesional oedematous-appearing parenchyma (compared to contralateral white matter; p < 0.001). Conclusion Tuberculomas demonstrate lower MTRasym ratios compared to HGG, reflective of a relative paucity of mobile amide protons in the ambient microenvironment. Elevated MTRasym values in perilesional parenchyma in tuberculomas are a unique observation that may be a clue to the inflammatory milieu.

scholarly journals NI-10 AVAILABILITY OF AMIDE PROTON TRANSFER-WEIGHTED MRI METRICS IN GLIOMA

2019 ◽  
Vol 1 (Supplement_2) ◽  
pp. ii27-ii27
Author(s):  
Shinji Yamashita ◽  
Minako Azuma ◽  
Kiyotaka Saito ◽  
Takashi Watanabe ◽  
Kiyotaka Yokogami ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Proton Transfer ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Amide Proton ◽  
Molecular Characteristics ◽  
Amide Proton Transfer ◽  
Apt Imaging ◽  
Glioma Grading ◽  
Mib 1

Abstract OBJECTIVE Chemical exchange saturation transfer (CEST) is a novel MR imaging contrast technique that relies on the molecular characteristics of the sample. Amide proton transfer (APT) imaging is an emerging CEST-based MR imaging technique that is sensitive to mobile proteins and peptides in the tissue. APT imaging has become increasingly recognized as a promising imaging modality for glioma. Several reports suggest that APT signals are a promising imaging biomarker for glioma grading and prediction of molecular marker status. In this study, we assessed the utility of APT imaging in glioma by evaluating the relationship between APT signals and clinical parameters in glioma. METHODS We enrolled 23 glioma patients (25 lesions) who underwent preoperative MRI with APT imaging and surgery at our institution between May 2018 and July 2019. The median age of patients was 64 years old (range, 14–84). 2 patients had Grade 2, 1 patient had Grade 3, and 22 patients had Grade 4. APT signals were measured inside the ROI that was manually placed in the solid portion of tumor that best represented the entire tumor signal on raw APT images. RESULTS We could see that the high APT signals seemed to be related to IDH wild status and high glioma grading (IDH status; p=0.171, Grade; p=0.113). Moreover, the high APT signals were significantly strong related to high Mib-1 LI (p=0.0068, cutoff: 3.295%, sensitivity: 83%, specificity: 71%). CONCLUSIONS APT imaging might be associated with IDH mutation status and glioma grading. Especially, high APT signal was a great predictor of high MIB-1 LI in glioma.

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