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Impact of 18F-FDG PET/MR based tumor delineation in radiotherapy planning for cholangiocarcinoma.
- Source :
- Abdominal Radiology; Aug2021, Vol. 46 Issue 8, p3908-3916, 9p
- Publication Year :
- 2021
-
Abstract
- Purpose: Radiation therapy (RT) is an effective treatment for unresectable cholangiocarcinoma (CC). Accurate tumor volume delineation is critical in achieving high rates of local control while minimizing treatment-related toxicity. This study compares <superscript>18</superscript>F-FDG PET/MR to MR and CT for target volume delineation for RT planning. Methods: We retrospectively included 22 patients with newly diagnosed unresectable primary CC who underwent <superscript>18</superscript>F-FDG PET/MR for initial staging. Gross tumor volume (GTV) of the primary mass (GTV<subscript>M</subscript>) and lymph nodes (GTV<subscript>LN</subscript>) were contoured on CT images, MR images, and PET/MR fused images and compared among modalities. The dice similarity coefficient (DSC) was calculated to assess spatial coverage between different modalities. Results: GTV<subscript>M</subscript><superscript>PET/MR</superscript> (median: 94 ml, range 16–655 ml) was significantly greater than GTV<subscript>M</subscript><superscript>MR</superscript> (69 ml, 11–635 ml) (p = 0.0001) and GTV<subscript>M</subscript><superscript>CT</superscript> (96 ml, 4–564 ml) (p = 0.035). There was no significant difference between GTV<subscript>M</subscript><superscript>CT</superscript> and GTV<subscript>M</subscript><superscript>MR</superscript> (p = 0.078). Subgroup analysis of intrahepatic and extrahepatic tumors showed that the median GTV<subscript>M</subscript><superscript>PET/MR</superscript> was significantly greater than GTV<subscript>M</subscript><superscript>MR</superscript> in both groups (117.5 ml, 22–655 ml vs. 102.5 ml, 22–635 ml, p = 0.004 and 37 ml, 16–303 ml vs. 34 ml, 11–207 ml, p = 0.042, respectively). The GTV<subscript>LN</subscript><superscript>PET/MR</superscript> (8.5 ml, 1–27 ml) was significantly higher than GTV<subscript>LN</subscript><superscript>CT</superscript> (5 ml, 4–16 ml) (p = 0.026). GTV<superscript>PET/MR</superscript> had the highest similarity to the GTV<superscript>MR</superscript>, i.e., DSC<superscript>PET/MR-MR</superscript> (0.82, 0.25–1.00), compared to DSC <superscript>PET/MR-CT</superscript> of 0.58 (0.22–0.87) and DSC<superscript>MR-CT</superscript> of 0.58 (0.03–0.83). Conclusion: <superscript>18</superscript>F-FDG PET/MR-based CC delineation yields greater GTVs and detected a higher number of positive lymph nodes compared to CT or MR, potentially improving RT planning by reducing the risk of geographic misses. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 2366004X
- Volume :
- 46
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Abdominal Radiology
- Publication Type :
- Academic Journal
- Accession number :
- 151456939
- Full Text :
- https://doi.org/10.1007/s00261-021-03053-4