3.0T MRI with functional sequences and respiratory motion-resolved compressed sensing reconstruction of free-breathing radial acquisition for immediate response assessment of lung tumour postablation
Danyang Zhao, Shanghai / China
Author Block: D. Zhao, L. Liu, X. Ye, k. liu, C. Yiheng, S. Yuanxin, F. Wang, H. Sun; Shanghai/CNPurpose: The purpose of this study was to use serial magnetic resonance imaging (MRI) examinations to observe changes in malignant lung tumours within a short time postablation.Methods or Background: Patients with primary or metastatic lung tumours eligible for ablation were included in this study. Ablation was performed according to standard procedures. Unenhanced and dynamic contrast-enhanced MRI scans were performed preablation and in one week after ablation. Dynamic imaging were undergone with free-breathing imaging technique combining compressed sensing (CS) and parallel imaging with golden-angle radial sampling instead of conventional breath-hold volumetric interpolated breath-hold examination (VIBE) or liver acquisition volume acceleration (LAVA). At each time point, the signal intensity and parameters of the ablation zone in both perfusion imaging and DCE imaging were examined and analysed.Results or Findings: Using CS technique we obtained T1-weighted imaging with high spatial resolution without requiring patients to hold their breath. A total of 19 nodules in 17 patients were included in the study. Among them, 16 nodules examined parameters of IVIM. The ablation zone in MRI imaging has been shown to have a central area with complete tissue necrosis showed no enhancement (19/19) on ceT- The value of Ktrans (18/19), D*(10/16), iAUC90(19/19), CER(19/19) were significantly lower in the postablation zone compared to the preablation tumour, which represents decreased blood flow perfusion. The increase in D value (11/16) and ADC value (13/16) indicates that the diffusion of water molecules is less restricted compared to before.
Conclusion: Patients who cannot hold their breath autonomously can get high-quality images and stable parameter data by CS technique. The ablative margin and the changes of tumour activity and microvascular perfusion can be analysed via functional MRI images, which can be used to assess immediate response with technical success and ablative margin.Limitations: The limitations of the study are the lack of cases and long-term follow-up data.Funding for this study: No funding was provided for this study.Has your study been approved by an ethics committee? Not applicableEthics committee - additional information: The study is retrospective.