1. DIAGNOSTIC ROLE OF STATIC AND DYNAMIC CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING IN THE EVALUATION OF SOFT TISSUE TUMOURS Abstract No. IRIA -1033 1

2. WHY THE STUDY? Imaging and pathological diagnosis of soft tissue tumours is an integral part of the management strategy but however, pose a great challenge. Routine MR imaging after contrast administration (Static contrast enhanced MRI- (SCE-MRI)) is unable to discriminate between benign and malignant lesions adequately Dynamic contrast enhanced MRI (DCE MRI) uses the Time intensity curve which helps in predicting the tumour characteristics, thus can differentiate between benign and malignant soft tissue tumours. 2

3. AIMS & OBJECTIVES 1.To characterize soft tissue tumours by dynamic enhanced contrast MRI 2.To assess the diagnostic role of dynamic and static contrast enhanced MRI in differentiating benign from malignant soft-tissue lesions 3.To compare the diagnostic power of different MRI parameters in predicting the malignant nature of soft tissue tumours 3

4. RESEARCH HYPOTHESIS Dynamic contrast enhanced MRI is superior to Static contrast enhanced MRI in predicting the benign / malignant nature of soft tissue tumours 4

5. MATERIALS AND METHODS 5

6. 6 61 SOFT TISSUE TUMOURS 54 soft tissue tumours 37 MALIGNANT 17 BENIGN CONVENTIONAL MRI DYNAMIC MRI STATIC MRI TRUCUT BIOPSY IMAGING & HISTOPATHOLOGICAL CORRELATION 7 excluded soft tissue tumours in the extremity/body who are referred for MRI Informed consent obtained  Contra-indication for MRI (those with pace makers, cochlear implants ) or gadolinium contrast (0)  Poor quality MR images(2)  Lesions originating from bone (1)  Recurrent lesions following chemotherapy or radiotherapy (2)  Inconclusive / non-availability of HPE findings (2) IMAGE INTERPRETATION blinded

7. CONVENTIONAL MRI 7 Location of the lesion ( body / extremity) lesion size margins signal intensity characteristics (T1 & T2) with respect to muscle involvement of bone, joint, neurovascular structures hemorrhage (+/-) T1 T2 STIR

8. DYNAMIC CONTRAST ENHANCED MRI T1 WEIGHTED FAT SUPPRESSED 2D SEQUENCES CONTRAST – dose 0.2 mmol/kg @ 2 ml/s  20 ml saline flush inversion preparatory pulse with a delay of 360 ms (TI); TR/TE of 518/1ms; flip angle 30 0 ; slice thickness 8mm, matrix 192 × 176 30-60 measurements in a scan time of ~ 5 minutes where each dynamic series had a scan time of ~ 5- 10 sec based on the number of measurements. 8

9. 9 no enhancement gradual increase of enhancement rapid initial enhancement followed by a plateau phase rapid initial enhancement followed by a washout phase rapid initial enhancement followed by sustained late enhancement. # with permission from vanRijswijk C.S.P et al.(2004) # TYPE 4

10. STATIC CONTRAST ENHANCED MRI 3 DIMENSIONAL T1 WEIGHTED FAST GRE SEQUENCE (VIBE) WITH FAT SUPPRESSION Acquired 5 minutes after the intravenous administration of contrast (TR/TE of 14.7-15/6.5; flip angle 10 0 ; FOV 400-420mm; slice thickness 1mm; NEX 1; matrix 384 X 448) STATIC ENHANCEMENT PATTERNS DIFFUSE / PERIPHERAL / HETEROGENEOUS / ABSENT NECROSIS PRESENT / ABSENT 10

11. STATIC ENHANCEMENT PATTERN 11 Diffuse – when the lesion enhanced uniformly Peripheral - when only the rim of the lesion showed enhancement Absent - no intralesional enhancement Heterogeneous

12. DATA ANALYSIS 12 Images were interpreted by a radiologist blinded to the histopathology static enhancement pattern Time signal intensity curve of dynamic MRI Overall MR imaging parameters CORRELATED WITH HISTOPATHOLOGY BENIGN / MALIGNANT

13. RESULTS 13

14. 14 MRI PARAMETERBENIGN (n=17)MALIGNANT (n=37)P VALUE Mean Age (years)28.444<0.05 Average diameter (cm)6.010.18<0.05 Margins <0.05 Well-defined165 Partially defined111 Infiltrating021 T1 signal intensity >0.05 < or = muscle46 Slightly > muscle1023 Higher than muscle38 T2 signal intensity <0.05 < or = muscle10 Slightly > muscle20 Higher than muscle1437 T 1 homogeneity >0.05 100% Homogeneous64 Intermediate820 > 50% Heterogeneous313 T 2 homogeneity <0.05 100% Homogeneous22 Intermediate138 > 50% Heterogeneous227

15. 15 MRI PARAMETERBENIGN (n=17)MALIGNANT (n=37)P VALUE MRI PARAMETER BENIGN (n=17) MALIGNANT (n=37) P VALUE Bone involvement >0.05 Nil1728 Erosion or periosteal reaction05 Invasion04 Neurovascular involvement <0.05 Encasement or infiltration07 Displacement217 Absent129 Not applicable34 Joint involvement >0.05 Present04 Absent1733 Hemorrhage <0.05 Present217 Absent1520

16. 16 MRI PARAMETERBENIGN (n=17) MALIGNANT (n=37) P VALUE Static enhancement pattern <0.05 Diffuse114 Peripheral23 Heterogeneous230 Absent20 Necrosis <0.05 Present229 Absent158 Dynamic Time signal intensity curve <0.05 Type 120 Type 2121 Type 329 Type 407 Type 5120

17. MRI in HISTOPATHOLOGICAL DIAGNOSIS 13 out of the 54 lesions (24%) 5 fat containing lesions (3 liposacrcoma 2 lipoma) 4 Vascular malformations (3 hemangiomas, 1 arterio- venous malformation) 2 neurofibroma 1 Desmoid tumour 1 benign fibrous tumour 17

18. 18

19. 19 SENSITIVITY SPECIFICITY POSITIVE PREDICTIVE VALUE (PPV) NEGATIVE PREDICTIVE VALUE (NPV) DEGREE OF AGREEMENT (KAPPA) STATIC CONTRAST ENHANCED MRI 76.4% 89.2% 76.4% 89.2% 0.65 DYNAMIC CONTRAST ENHANCED MRI 93.3% 92.3% 82.3% 97.3% 0.82 OVERALL IMAGING 93.7%94.5%88.2%97.3%0.87

20. DISCUSSION 20

21. DEMOGRAPHICS 69% of the cases were malignant which is quite contradictory to the incidence in the general population. Benign 100 times commoner. MRI was done for surgical planning, pre chemotherapy size assessment Benign lesions – directly excised / left alone the gender and lesion location had no influence on the occurrence of soft tissue tumours or malignant lesions. 21

22. STATIC ENHANCEMENT PATTERN STATIC ENHANCEMENTBENIGN (n=17)MALIGNANT (n=37) Diffuse11 4 ( 2 DFSP, low grade spindle cell tumour and MPNST Peripheral 2 (large leiomyoma, low grade spindle cell tumour) 3 Heterogeneous 2 (Hemangioma, benign fibrous tumour) 30 Absent2 (Lipoma)0 22

23. TIME SIGNAL INTENSITY CURVE 23 Dynamic Time signal intensity curve BENIGN (n=17) MALIGNANT (n=37) Type 120 Type 2121 (low grade MPNST) Type 3 2 (hemangioendothelioma, Low grade spindle cell tumour) 9 Type 407 Type 51 (Desmoid tumour)20

24. 24 BENIGN

25. 25 HISTO-PATHOLOGY DESMOID TUMOUR – BENIGN LOCALLY AGGRESIVE TYPE 5 CURVE - MALIGNANT

26. 26 Imaging- malignant Type 5 time signal intensity curve HISTOPATHOLOGY – TRUCUT specimen- Low grade spindle cell tumour. Was reported as benign

27. 27 HEMANGIO-ENDOTHELIOMA

28. MERITS OF THE STUDY Study was able to answer the objectives Good imaging and pathological correlation demonstrated in this study can be used to assess benign / malignant nature of lesions in sites in- accessible for diagnostic biopsy Post biopsy / post chemotherapy / radiotherapy cases excluded. (dynamic MRI would give inaccurate results) 28

29. LIMITATIONS RECOMMENDATIONS large proportion of malignant lesions (due to the convenient sampling done) Small sample size- had to combine groups of time signal intensity curves and static enhancement patterns. Intermediate malignant group on histopathology not included Include all cases of clinically diagnosed soft tissue tumours Recruit a larger sample size. 29

30. LIMITATIONS RECOMMENDATIONS Difficulty in achieving smooth time signal intensity curve in intra- abdominal masses Histopathology of either trucut biopsy and resected specimens was used. region of interest for dynamic sequences can be kept in an enhancing area least affected by movement (pelvis) Taking histopathology of resected specimen only as gold standard 30

31. CONCLUSION Adequate tissue characterization is possible using MRI and can provide exact histopathological diagnosis in certain tumours The addition of static and dynamic contrast enhanced MRI to the conventional sequences increases the ability to categorize these lesions accurately into benign and malignant respectively. The higher specificity (92.3% vs 89.2%)and degree of agreement (K 0.82 vs 0.65) with the histopathology, of dynamic contrast enhanced MRI over static contrast enhanced MRI 31

32. CONCLUSION Presence of infiltrating margins neurovascular encasement bone invasion joint involvement rapid enhancement with washout on signal intensity curve had a 100% positive predictive value for malignancy. 32

33. REFERENCES Park MY, Jee W-H, Kim SK, Lee S-Y, Jung J-Y. Preliminary Experience Using Dynamic MRI at 3.0 Tesla for Evaluation of Soft Tissue Tumours. Korean J Radiol. 2013;14(1):102. Van Rijswijk CSP, Geirnaerdt MJA, Hogendoorn PCW, Taminiau AHM, van Coevorden F, Zwinderman AH, et al. Soft-Tissue Tumours: Value of Static and Dynamic Gadopentetate Dimeglumine–enhanced MR Imaging in Prediction of Malignancy. Radiology. 2004 Nov 1;233(2):493–502. 33

34. REFERENCES Fletcher CD, Unni KK, Mertens F, eds.World Health Organization classification of tumours. Pathology and genetics of tumours of soft tissue and bone. Lyon, France: International Agency for Research on Cancer, 2002. Sen J, Agarwal S, Singh S, Sen R, Goel S. Benign vs malignant soft tissue neoplasms: Limitations of magnetic resonance imaging. Indian J Cancer. 2010;47(3):280. Daniel A, Ullah E, Wahab S, Kumar V. Relevance of MRI in prediction of malignancy of musculoskeletal system-A prospective evaluation. BMC Musculoskelet Disord. 2009 Oct 8;10:125. 34

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