cases

1. cases Dr Payal Damor R2 Radio diagnosis S.S.G.H BARODA 25-11-08

2. Case 1

3. 40 yr female come with Lt sided breast discomfort since 2 weak, she underwent breast implantation 8 yrs back.

4. T1W & T2W axial MRI of both breasts shows bilateral saline implant , Rt implant is ant to pectoralis muscle & in sub glandular location, it appears to be intact ,Lt implant post to pectoralis muscle & in sub pectoral location ,it is rupture & shows collapsed & folded shell floating in saline s/o linguine sign in c/o Lt intra capsular silicone implant rupture.

5. DIAGNOSIS: Left sub pectoralis intra capsular silicon implant rupture

6. 2 COMMON DESIGN OF IMPLANT SINGLE LUMEN DOUBLE LUMEN It contain free silicone gel in a textured or non textured silicone membrane. It usually have a saline outer shell that surrounds a silicone inner shell.

7. Single-lumen gel-saline implant. Axial T2-W fast spin-echo water-suppressed MR image of an intact single-lumen implant with a leaflet valve, showing the normal appearance of numerous waterlike bubbles (a, dark) mixed with silicone gel (b, bright). A cross section through the distal flat part of the leaflet valve is shown (arrow).

8. Reverse double-lumen adjustable implant. Axial T2-W fast spin-echo water-suppressed MR image of double-lumen implant This image shows the normal water-suppressed appearance of mixed saline (a, dark) and silicone gel (b, bright), both in the inner lumen, and silicone gel in the outer lumen (c).

9. sub glandular location sub pectoral location 2 SITES OF IMPLANT Posterior to pectoralis muscle Implantation here is technically more difficult. lower incidence of capsular contracture & results in a less obvious scar. Also, with this approach, evaluation of breast tissue at mammography is easier. Anterior to pectoralis muscle Implantation here is technically easier.

10. MRI -----normal implant • Smooth, low–signal-intensity silicone membrane shell • Low–signal-intensity radial folds in the shell (These may be complex, and they always abut the implant at its periphery and span the gel substance only at periphery.) • A few internal water droplet signals (common; not a reliable indication of rupture) • Reactive fluid around textured implants (common; not indicative of rupture) • Fibrous capsule (dark, ringlike structure around the implant)

11. Coronal T1W MRI: a normal radial fold, which appears as a low signal intensity line through the implant.

12. MRI can be used to exploit differences in silicone, water, and fat resonance frequencies to deliver high-resolution images of SGBIs. • The approximate resonance frequency of silicone is 100 Hz lower than that of fat and 320 Hz lower than that of water. • Because the resonance of silicone is similar to that of fat, silicone appears similar to fat on non selective chemical fat- or water-suppressed images. • On short–inversion time inversion-recovery (STIR) images, the fat signal is suppressed and water and silicone are bright. • Water-suppressed STIR sequences produce a silicone-only image. Chemical-shift imaging with the modified 3-point Dixon protocol provides both a silicone-only and a water-and-fat image with a single sequence.

13. MRI --- Relative Appearances of Silicone, Fat, and Wateron MRI of SGBI Rupture* Silicone-only image: WS STIR, 3-point Dixon • Dark silicone: fat-suppressed T1 • Bright silicone: water-suppressed T2 • Scarring may obscure silicone mass FSE-fast spin echo

14. Sagital Inversion recovery MRI: intact silicone gel breast implant (SGBI).

15. 2 TYPES OF RUPTURE INTRACAPSULAR EXTRACAPSULAR Most common Occurs when silicone escapes silastic membrane shell but is contained in fibrous capsule. Involves escape of free silicone gel through fibrous capsule, with extravasation into breast tissue. Migration of silicone to axillary lymph nodes may be present.

16. Intra capsular rupture • The linguine sign refers to a collapsed & folded elastomer shell that is floating in gel. This is the most reliable sign of Intracapsular rupture. • The keyhole (i.e., teardrop, inverted teardrop, noose) sign refers to the presence of silicone both inside & outside a radial fold. • Extra capsular rupture • Macroscopic extrusion of silicone through fibrous capsule into surrounding parenchyma, pectoralis muscle, or lymph nodes is present. • Findings in Intracapsular rupture should be expected.

17. MRI --- Linguine sign • Indicates intracapsular rupture of the breast implant. • Most sensitive among all signs of intracapsular rupture from other imaging modalities, with a sensitivity of 96% & a specificity of 94% . • Wavy lines on MR images represent collapsed shell floating in silicone. • Although linguine sign is fairly easy to detect, the signs of early intracapsular rupture (tear drop sign, keyhole sign, subcapsular line sign) were more common than linguine sign .

18. Sagittal T2-W short-T1 inversion-recovery MR image obtained with fat suppression shows intracapsular rupture of a silicone breast implant, as demonstrated by presence of wavy lines which represent collapsed shell floating in silicone. s/o linguine sign (arrow).

19. Sagital MR images demonstrate bilateral subpectoral silicon breast implants, with rupture of both implant membranes ( "linguini sign"). A "water-droplet" sign is also seen on a couple of images. Silicon is contained within the fibrous capsule, consistent with intracapsular rupture. No free silicon is identified within the breast tissue

20. MRI ---keyhole sign, noose sign,inverted teardrop sign • Trapping of small amount of silicone gel within a radial fold • Silicone on both sides of the elastomer shell • Small intracapsular rupture or large gel bleed: cannot be differentiated!!!

21. FSE T2WI: keyhole signSilicone appears on both sides of the radial fold. The DDx includes intracapsular rupture and extensive gel bleeding. A small water droplet is in the posterior aspect; small water droplets have no prognostic importance in silicone gel breast implant rupture.

22. MR image shows the keyhole, or inverted teardrop sign. The linguine sign was present elsewhere on the image, and a portion of the linguine is adjacent to the keyhole sign. These findings are consistent with an intracapsular silicone gel breast implant rupture.

23. MRI ---extracapsular rupture • Rupture of both elastomer shell (envelope) and fibrous capsule • Silicone outside implant + linguine sign • Best seen on silicone-only sequence: • Bright silicone in dark tissue (Silicone outside implant) • Dark lines in bright silicone (linguine sign)

24. Extra capsular silicone, with a high-signal-intensity lesion in axilla, which is compatible with silicone in node

25. A. T1WI (manually fine-tuned to suppress the silicone peak): extracapsular silicone posteriorly (low SI)B. Water-suppressed FSE T2WI: extracapsular silicone posteriorly (high SI). Note the hypointense thin lines in the interior of the implant: collapsed elastomer shell  implant rupture.

26. Internal rupture of double-lumen implants Failure of the inner shell may be depicted as saline droplets that are floating in the silicone gel; this is considered a form of intracapsular rupture. • The presence of some saline droplets is a normal finding in single-lumen implants. • Capsular contracture • Asymmetric, serrated, focal folding of the fibrous capsule that changes the normal ovoid appearance of the implant may be present. (A transverse diameter of less than twice the anteroposterior depth corresponds well to clinically evident contracture)

27. Management of ruptured SGBIs Involves explantation of prosthesis, with or without reconstruction. • Reasons for removal include the potential for silicone migration with subsequent inflammatory reaction; development of adverse local symptoms in pt, including pain, deformity,& granuloma formation. pts who have symptoms of connective tissue disease, fibromyalgia, or chronic fatigue syndrome is advocated as well.

28. Screening for SGBI rupture in asymptomatic women remains controversial. • Some authors advocate mass screening with MRI, while others advocate prophylactic removal at or around 8-10 years after implantation. • Still others advocate no removal unless pt is symptomatic & has imaging & clinical evidence of rupture.

29. Case 2

30. Six year-old female presents with • Two months of decreasing vision • Right eye-Squint

31. Coronal & axial NCCT scan showing well defined water density lesion in super cellar region & calcification in ant clinoid process with effacement of frontal horn of lat ventricle.

32. Differential Diagnosis -cystic suprasellar mass • Craniopharyngioma • Rathke cleft cyst • Arachnoid cyst. • Epidermoid.

33. Craniopharyngioma • Arise from squamous rests along Rathke’s cleft. RULE OF 90 • 90% in children • 90% supra sellar with /without intra sellar component. • 90% cystic lesion with solid mural nodule. • 90% nodular / rim calcification • 90% nodular / rim enhancement

34. CT • NC– cystic lesion with a solid mural nodule & calcification • CE–rim enhancement MRI • CYST– hypointense on T1 & hyper intense on T2 WI with strong heterogeneous enhancement on Gd enhanced T1 WI.

35. Sagittal unenhanced (a) and coronal contrast-enhanced (b) T1-W MR images show a lobulated suprasellar tumor with intrasellar extension. The tumor is formed predominantly of multiple cysts with varying signal intensities that show thin mural contrast enhancement (arrows in b) along with associated asymmetric lateral ventricular dilatation in c/o craniopharyngioma in a 12-year-old boy with headache and blurred vision.

36. Rathke cleft cyst • This is a macroscopic cyst arising from the remnant of Rathke’s pouch. • Any age (mean 38 yrs). • Female : male = 2-3 : 1 • Location– 70% intra & supra sellar, 25%- intrasellar, < 5% suprasellar.

37. Imaging • NCCT – Discrete low density lesion, non-calcified & does not have a solid component. • CECT– Capsular enhancement is seen in 50% of cases. • MRI– T1WI – hyperintense to brain (75% of cases) T2WI – hyperintense (50%), isointense (25%), hypointense (25%) Typically do not enhance on Gadolinium administration on T1WI.

38. Sagittal T1W and coronal T2W scans showing well defined lesion in sellar region with extension in to superacellar region ,the lesion appears hyper intense on both T1 & T2 w images. In c/o rathke cleft cyst.

39. Arachnoid Cyst • 75% occur in children • Male : female = 3:1. • CT– extra axial mass with CSF density (5-15 HU) with no solid component / enhancement / calcification. • MRI – Suprasellar mass with signal intensity similar to CSF on all pulse sequences. T1 – hypo T2 – hyper FLAIR – loss of signal DW – loss of signal

40. Coronal CECT image shows well defined csf denisty(5-15 HU) lesion a sellar & suprasellar region, with minimal wall enhancement , but no solid componant / calcification in c/o arachnoid cyst. Coronal T1W MRI image shows well defind csf denisty lesion in sellar & superasellar region displacing the pituitary downwards & optic chiasm upwards.

41. Epidermoid tumor • Developmental epithelial inclusion cyst • Majority are intradural (basal CSF spaces) • 40-50% CP angle cistern, 7% each in supra and para sellar regions. • Epidermoids are confined to & insinuate along basilar CSF cisterns. They typically encase & engulf arteries & cranial nerves.

42. Imaging • SI similar to CSF • T1 – hypo SI • T2 – hyper SI • FLAIR –Marked loss of SI noted. • Occasionally, Epidermoid may not show loss of SI on FLAIR because of high protein content.

43. Diffusion-weighted imaging • Useful method to differentiate Epidermoid tumors from arachnoid cysts, by revealing the solid nature of Epidermoid tumors as opposed to the fluid properties of arachnoid cysts according to their apparent diffusion coefficients (ADC). • All epidermoid tumors are markedly hyperintense relative to the brain & CSF on DW imaging, whereas Arachnoid cysts are hypointense.

44. Axial T1&T2 W MRI image showing well defined lesion in sellar region which appear hypointense on T1 & hyperintense on T2 W IMAGES.

45. The lesion shows high signal intensity on DWI. In c/o epidermoid.

46. DWI -hyper epidermoid

47. In the present case

48. Diagnosis Craniopharyngioma

49. Discussion • Accounts for 50% of all suprasellar tumors in children.  • Most common nonglial brain tumor in children.  • It is predominantly a pediatric tumor, although it is also seen in adults about 25% of the time. • Arise from squamous epithelial rests along the involuted craniopharyngial duct .

50. It is a histologically benign, extra-axial, slow-growing tumor that predominately involves sella & suprasellar space. • Despite its histologic appearance, it occasionally behave like malignant tumors & can metastasize. • Recurrence, both local & along surgical tracts & meningeal seeding have been reported.