1. Magnetic Resonance Imaging Findings of Grafted Cancellous Allografts after Removal of Bone Tumors Seungcheol Kang, Ilkyu Han, Sunghwan Hong, Hwan Seong Cho, Han-Soo Kim Musculoskeletal Tumor Center, Seoul National University Cancer Hospital, Seoul, Korea - CTOS 2014 -

2. Cancellous Allograft Allograft : Donor site morbidity↓ / Quantity ↑ → Commonly used in bone tumor surgery Cancellous allograft : Fill defect after curettage of bone tumor

3. MRI in Bone Tumors Follow-up modality for surveillance of recurrence Curettage + Cancellous allograft → MRI DDx. cancellous allograft vs. recurred tumor No report on MRI findings of cancellous allograft

4. Purpose To investigate the MRI features of Cancellous allograft & their change over time Cancellous allograft vs. Recurred tumors

5. Reviewed (n=53)  Curettage and cancellous allograft between 2002~2011  MRI for follow-up  Metallic device, BMP, or calcium component (n=17)  Lost to follow-up within 1 year after imaging (n=2) Analyzed (n=34) Excluded (n=19) Patient Selection

6. Age: 27 years (11-64) Sex: M (18) F (14) Tumor type Chondroblastoma (11), LG chonsa (10), ABC (3), GCT (2), FD (2), SBC (2), IO lipoma (1), PVNS (1) Site Femur (12), tibia (8), pelvis (5), humerus (4), foot (4) Tumor size: 6.7 ± 6.3 cm Patient Characteristics

7. 1.5- or 3.0-Tesla MRI scanners Sequences T1WI: spin-echo T1-weighted T2WI: fast spin-echo T2-weighted Enhanced T1: gadolinium-enhanced spin-echo T1WI Review by 2 independent authors Acquisition of MRIs

8. 66 MRIs in 34 patients  1 MRI: 17 patients  ≥ 2 MRIs: 17 patients Time from Surgery to MRI: 23 months (3-94) Time interval Analysis of MRIs Surgery6mon1yr2yr3yr 12 MRIs 17 MRIs 18 MRIs 11 MRIs 8 MRIs

9. Typical MRI features of cancellous allograft Changes of cancellous allograft over time  Typical MRI features  Graft incorporation  GD enhancement Tumor recurrence Analysis Points

10. Results

11. Typical MRI Features T1  Homogeneous intermediate SI  ±Speckled hyperintensities

12. Typical MRI Features T1  Homogeneous intermediate SI  ± Speckled hyperintensities T2  High SI  ± Speckled hypointensities

13. Typical MRI Features T1  Homogeneous intermediate SI  ± Speckled hyperintensities T2  High SI  ± Speckled hypointensities Enhanced T1  Peripheral rim enhance  ± Central heterogeneous enhance

14. Typical MRI Features T1  Homogeneous intermediate SIs  ± Speckled hyperintensities T2  High SIs  ± Speckled hypointensities Enhanced T1  Peripheral rim enhance  ± Central heterogeneous enhance Present in all cases (n=12)

15. Changes of Typical MRI Features T1 100 % 82 % 67 % 60 % 0%0% T2 100 % 59 % 33 % 17 % 0%0% En- T1 100 % 87 % 50 % 0%0% Surgery6mon1yr2yr3yr Changes of Over Time

16. Graft Incorporation Peripheral0%0% 24 % 50 % 54 % - Complete0%0% 0%0% 17 % 46 % 100 % Total0%0% 24 % 67 % 100 % Surgery6mon1yr2yr3yr Changes of Over Time

17. Graft Incorporation PO 10monPO 18mon Changes of Over Time

18. GD Enhancement 100 % 59 % 33 % 17 % 0%0% Surgery6mon1yr2yr3yr Changes of Over Time

19. PO 5mon PO 34mon GD Enhancement Changes of Over Time

20. Suspicious Recurrence on MRI (n=8) No recurrence (n=3) Recurrence on MRI Recurrence (n=5) vs. Recurrence

21. Suspicious Recurrence on MRI (n=8) No recurrence (n=3) Recurrence on MRI Recurrence (n=5)  Same SI with primary tumor vs. Recurrence

22. Recur Initial Recurrence PO 9 mon vs. Recurrence

23. Suspicious Recurrence on MRI (n=8)  MRIs < 1 year after surgery  Chondrosarcomas No recurrence (n=3) Recurrence on MRI Recurrence (n=5) vs. Recurrence

24. No Recurrence PO 23 mon Pre-opFU vs. Recurrence

25. T1T2En-T1 PO 12mon vs. Recurrence

26. T1T2En-T1 PO 12mon PreOp vs. Recurrence

27. T1T2En-T1 PO 12mon PreOp vs. Recurrence

28. T1T2En-T1 PO 12mon PreOp vs. Recurrence

29. T1T2En-T1 PO 12mon PreOp vs. Recurrence

30. T1T2En-T1 PO 12mon PreOp vs. Recurrence

31. Summary & Conclusion This study assessed the MRI features of cancellous allografts & their change over time, and the differentiating features between cancellous allografts and recurred tumors.

32. Summary & Conclusion This study assessed the MRI features of cancellous allografts & their change over time, and the differentiating features between cancellous allografts and recurred tumors. Cancellous allografts typically showed homogeneous intermediate or low SIs on T1, high SIs with speckled hypointensities on T2, and peripheral rim enhancements on enhanced T1.

33. Summary & Conclusion This study assessed the MRI features of cancellous allografts & their change over time, and the differentiating features between cancellous allografts and recurred tumors. Cancellous allografts typically showed homogeneous intermediate or low Sis on T1, high SIs with speckled hypointensities on T2, and peripheral rim enhancements on enhanced T1. These typical features were maintained until 6 months and then gradually disappeared by 3 years.

34. Summary & Conclusion Graft incorporation occurred from periphery to center and were completed within 3 years.

35. Summary & Conclusion Graft incorporation occurred from periphery to center and were completed within 3 years. The single most differentiating feature of a recurred tumor was showing the similar pattern and SI of the primary tumor.

36. Summary & Conclusion Graft incorporation occurred from periphery to center and were completed within 3 years. The single most differentiating feature of a recurred tumor was showing the similar pattern and SI of the primary tumor. Careful interpretation is warranted when dealing with chondroid tumors, especially for MRIs performed within 1 year of surgery.