Speaker
Description
Purpose: 18F-FDG PET/MR offers a unique opportunity to probe the biology of small renal masses (SRMs; cT1a ≤4cm). To address the low spatial resolution of PET (4-5 mm), our aim is to improve the delineation and quantification of SRMs in PET through contrast-enhanced MR-guided reconstruction.
Method: A FDG PET/MR examination was performed in an mMR for a patient with a known SRM. Furosemide (20 mg) was injected to suppress background uptake in the kidney. As the SRM did not show activity above the renal parenchyma, a PET-avid SRM with the same size and location of the known SRM was inserted into PET images, realistically and efficiently simulating a lesion with low uptake (signal-to-background ratio of 2). High resolution PET images were reconstructed through the One-Step Late Bowsher (OSL-Bow) algorithm with a high-resolution MR prior and compared with post-smoothed conventional reconstruction.
Result: In terms of visually comparing the synthetic SRM, our OSL-Bow implementation is superior to the post-smoothed reconstruction. Higher regularization enhances the edges of the SRM, reduces bias, but leads to increase variance compared to lower regularization.
Discussion and Conclusion: We have demonstrated the feasibility of MR-guided image reconstruction to improve the delineation and quantification of SRMs. For further investigation, we will assess our implementation with clinical data, including PET-avid SRMs.
| Field | Software and quantification |
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