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Improving liver lesion characterisation using retrospective fusion of FDG PET/CT and MRI
Arman Parsai1, Marc E Miquel1, Hikmat Jan2
1Barts Health NHS Trust, United Kingdom of Great Britain and Northern Ireland; Queen Mary University London, United Kingdom of Great Britain and Northern Ireland.
Aim:
To compare retrospectively fused FDG PET/CT and MRI (PET/MRI) to FDG PET/CT and MRI for characterisation of indeterminate focal liver lesions as malignant or benign in patients with a known primary malignancy.
Materials And Method:
A retrospective review of 70 patients (30 females, 40 males; mean age 56 ± 14 years) with 150 indeterminate lesions after FDG PET/CT and MRI (mean scan time interval 21 ± 11 days). HERMES® software was used to fuse PET/CT and MRI scans which were reviewed by 2 readers using the Likert score (scale 1-5) to characterise lesions as benign (1-3) or malignant (4-5). Final diagnosis was determined by histopathology or follow up imaging. Results for fused PET/MRI were compared to PET/CT and MRI alone.
Results:
For detection, MRI and fused PET/MRI detected all the lesions while PET/CT detected 89.4%. Characterisation of liver lesions as malignant on PET/CT alone yielded sensitivity, specificity, accuracy, PPV and NPV of 55.6%, 83.3%, 66.7%, 83.3%, 55.6% respectively and 67.6%, 92.1%, 80%, 89.3%, 74.5% for MRI, respectively. The sensitivity, specificity, accuracy, PPV and NPV for characterising lesions as malignant increased to 91.9%, 97.4%, 94.7%, 97.1%, 92.5% with PET/MRI fusion. The sensitivity, specificity, accuracy, PPV and NPV of fused PET/MRI for characterising lesions as malignant remained superior to PET/CT and MRI.
Conclusion:
Retrospective fusion of PET with MRI has improved characterisation of indeterminate focal liver lesions compared to MRI or FDG PET/CT alone.
Insights
Retrospective fusion of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and magnetic resonance imaging (MRI) significantly improves the characterization of indeterminate focal liver lesions. Fused PET/MRI demonstrated superior accuracy in differentiating malignant from benign lesions compared to standalone imaging modalities.
Area of Science:
- Radiology and Imaging
- Oncology
- Hepatology
Background:
- Indeterminate focal liver lesions present a diagnostic challenge in patients with known primary malignancies.
- Accurate characterization of these lesions is crucial for appropriate patient management and treatment planning.
- Conventional imaging techniques like FDG PET/CT and MRI have limitations in definitively differentiating benign from malignant liver lesions.
Purpose of the Study:
- To retrospectively compare the diagnostic performance of fused FDG PET/CT and MRI (PET/MRI) against standalone FDG PET/CT and MRI.
- To evaluate the efficacy of PET/MRI in characterizing indeterminate focal liver lesions as malignant or benign.
- To assess the improvement in diagnostic accuracy offered by retrospective PET/MRI fusion.
Main Methods:
- Retrospective review of 70 patients with 150 indeterminate liver lesions.
- HERMES® software used for retrospective fusion of FDG PET/CT and MRI scans.
- Lesion characterization using a Likert score (1-5) by two independent readers; final diagnosis confirmed by histopathology or follow-up imaging.
Main Results:
- Fused PET/MRI detected all lesions, outperforming PET/CT (89.4% detection).
- PET/MRI fusion significantly improved sensitivity (91.9%), specificity (97.4%), and accuracy (94.7%) in characterizing lesions as malignant compared to PET/CT and MRI alone.
- PET/MRI demonstrated superior performance metrics including positive predictive value (PPV) and negative predictive value (NPV) over individual modalities.
Conclusions:
- Retrospective fusion of FDG PET/CT and MRI enhances the characterization of indeterminate focal liver lesions.
- PET/MRI fusion offers superior diagnostic accuracy for differentiating malignant from benign liver lesions compared to standalone PET/CT or MRI.
- This technique holds significant potential for improving clinical decision-making in patients with liver lesions.
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