CT and MRI Imaging Spectrum of Orbital Masses: A Pictorial Essay.

Transcription

1 CT and MRI Imaging Spectrum of Orbital Masses: A Pictorial Essay. Poster No.: C-1556 Congress: ECR 2014 Type: Educational Exhibit Authors: I. Chouchene, S. MAJDOUB, A. Achour, H. Zaghouani, M Limeme, T. Reziga, H. Amara, D. Bakir, C. Kraeim ; Sousse/ 2 TN, Sousse, Tunisia/TN Keywords: Neoplasia, Diagnostic procedure, MR-Spectroscopy, CT-High Resolution, Head and neck, Eyes DOI: /ecr2014/C-1556 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 45

2 Learning objectives - Description and illustration of clinical, histological and imaging findings seen with the spectrum of orbital masses - Recognize the high resolution computed tomography (HRCT) and MRI findings of orbital tumor and pseudotumor Page 2 of 45

3 Background Orbital masses can result from a wide spectrum of etiologies and can often be challenging to diagnose with certainty. though ct scan is the firs tmodality of imaging investigation in evaluation of traumatic & in acute settings, MRI is an excellent diagnostic tool because of its inherent soft tissue Ccontrast & resolution. The imaging appearance of orbital masses can also be highly variable. Possible etiologies of orbital masses can routinely include Malignant Neoplasms, Vascular Lesions, Benign Neoplasms, Congenital Lesions, Inflammatory/ Infectious Lesions and Miscellanous etiologies (Including Thyroid eye disease, Anatomic EOM variants, Optic Nerve Drusen, Fibrous Dysplasia, Tolosa-Hunt Syndrome, Melanocytic Hamartoma, Orbital Mucocele, Amyloid, and Sub-periosteal Orbital Hematoma). Imaging has a major role in the diagnostic process and is essentially based on MRI. It also specify the location of the lesion, its structure and impact ontheorbitalcomponents. Page 3 of 45

4 Findings and procedure details SCANNING PROTOCOLS : PRE-CONTRAST: AXIAL-T1 NON-FAT SAT, T1 FAT SAT, T2 NON FAT SAT, T2 FFE CORONAL-T1 FAT SAT, T2 NON-FAT SAT SAGITAL-T1 FAT SAT, T2 FAT SAT POST-CONTRAST: AXIAL-T1 FAT SAT SAGGITAL-T1 FAT SAT (OTHER ADDITIONAL SEQUENCES WERE OBTAINED AS REQUIRED) IMAGING FINDINGS : Imaging Findings: This pictorial review looks at intra and extra-ocular pathologies, some of which are primary and others secondary to spread from a neighbouring region of pathology or due to a systemic condition. The list is by no means exhaustive. Case 1 :(Fig 1to 5) MR imaging for bilateral proptosis was performed in a middle aged female patient with known thyroid disease. This showed extensive enlargement of the extra ocular muscles bilaterally, most severely affecting the inferior rectus muscles with involvement of the muscle belly and sparing of tendons. Mild increase in the retro orbital fat noted bilaterally with proptosis. Diagnosis: Findings consistent with thyroid eye disease. Case 2 : (Figs. 6 to 9) Patient presented with blindness in the right.ct orbits showed abnormal soft tissue in the right orbit, extending to Page 4 of 45

5 the orbital apex with important enhancement. MRI shows low signal characteristics on T2 weighting and intermediate signal on T1 weighting. Displacement of the optic nerve noted on the right side. Diagnosis: Inflammatory pseudo tumour. Case 3: (Figs. 10 to 12)35 years old patient with bilateral lachrymal gland swelling. On MR scan, both lachrymal glands showed diffuse enlargement with the right being larger than the left. The adjacent lateral rectus muscle on both sides was displaced but not involved. There was no bone involvement. A degree of bilateral proptosis slightly more marked on the right was noted with quite marked soft tissue thickening of the soft palate. The swelling of the soft palate lachrymal glands and parotid glands all showed the same signal intensity on the T2 W coronal images suggesting a common pathology. Diagnosis: zone lymphoma of the lachrymal glands Case 4 : (Figs.13 to 16) Patient with known NF1 presented with painless proptosis. MR brain showed expansion of the right optic nerve. The absence of bull's eye appearance on coronal images and the a kinked appearance on sagittal images give an indication of diagnosis. A position also indicates the diagnosis (meningioma is usually sited nearer the orbital apex). Diagnosis: right optic nerve glioma. Case5: (Fig 17 to 19) A 50-year-old female presented to the Neurosurgery clinic with dimness of vision and proptosis of her left eye An MRI brain scan with orbit protocol was obtained. It demonstrated heterogeneous enhancement involving the left orbital apex,extending to the right cavernous sinus, with linear thick nodular enhancement involving the dura overlying the right temporoparietal lobes. Precontrast T-weighted images demonstrated bony expansion with predominantly Page 5 of 45

6 low marrow signal involving the right sphenoid wing and right lateral orbital wall. On T2weighted images,these demonstrated slightly hyperintense signal. Noncontrast maxillofacial CT images were obtained for pre-operative planning and showed a hyperostotic calvarial mass, primarily involving the left sphenoid wing, with involvement of the left lateral orbital wall, the anterior clinoid process, and the lateral wall of right sphenoid hemisinus. Diagnosis: spheno orbital meningioma Case 6: (Fig 20 to 22) 6 years old Patient with decreased right eye vision underwent MR Brain and orbits At T2 weighted imaging, the tumour dark compared with the vitreous. The calcified areas appear as hypointense foci within the tumour on gradient-echo T2 weighted and 3D FSE T2weighted images. On T1 weighted imaging, the tumor is slightly hyperintense to the vitreous. The tumour shows moderate to marked enhancement. On enhanced T1 weighted images, finely dispersed areas of very low signal intensity became visible inside the tumour that correspond to areas of calcification. The tumour shows restricted diffusion on diffusion weighted imaging at high b values. It exhibits low ADC values in contrast to the high intensity of the vitreous in the ADC maps Diagnosis: retinoblastoma Case 7: (fig 23 to 25) Patient of 5 years old with left proptosis MRI of the orbit revealed well-defined cystic lesion, appearing hypointense on T1W sequences hyper intense on T2W sequences and hypo in- tense on T2W FLAIR sequence, supero-me- dially involving the extra-ocular but intra and extra-conal compartment of the left orbit with mild peripheral enhancement of its walls and there was no significant peri-lesional edema. Diagnosis: orbital hydatid cyst Case 8: ( fig 26 to 29 )42 years old female patient with no medical history. lesions were seen as hypointense in T1-weighted sequences and as hyperintense in T2-weighted sequences of MRI. There was no heterogeneous contrast enhancement. Cystic/necrotic areas were seen as hyperintense images on T2-weighted sequences. Page 6 of 45

7 While bone marrow involvement was shown more clearly with MRI, compression of cranial and spinal nerves was determined most effectively by evaluation of CT and MRI together. CT and MRI were employed together in order to demonstrate the extent of disease, and complications of craniospinal involvement of PFD in patients with MAS. Diagnosis : fibrous dysplasia Case 9: (fig 30 to 32 )A 77-year-old man was referred for an abnormal retinal exam. Orbital MRI shows a POSTERIOR SEGMENT OF RIGHT EYE-GLOBE SHOWS WELLDEFINED MASS LESION, INTERMEDIATE TO HYPER-INTENSE ON T1W, HYPO-INTENSE ON T2W WITH MILD ENHANCEMENT Diagnosis: choroidal melanoma Case 10: (fig 33 to 36 ) A 48-year-old male patient presented at our clinic complaining of proptosis that had persisted for 2 weeks in his right eye MRI shows an intraconal tumor of with low signal intensity on T1-weighted image (A,B) and moderate enhancement on enhanced scan (C). On a T2-weighted image, the lesion is isointense to extraocular muscles and hypointense to orbital fat. The proximal muscle is splayed rather than compressed, suggesting that the lesion originated within the medial rectus. Diagnosis: rhabdomyosarcoma. Page 7 of 45

8 Images for this section: Fig. 1: Thyroid eye disease : axial CT right eye proptosis Page 8 of 45

9 Fig. 2: CT coronal :bilateral enlargement of the extra ocular muscles. Page 9 of 45

10 Fig. 3: Intra-orbital muscle involvement by thyroid eye disease. Page 10 of 45

11 Fig. 4: Thyroid eye disease - increased retro-orbial fat. Page 11 of 45

12 Fig. 5: Intra-orbital muscle involvement by thyroid eye disease. Page 12 of 45

13 Fig. 6: Inflammatory pseudotumour of the right orbit - T 1 FS Coronal Page 13 of 45

14 Fig. 7: Inflammatory pseudotumour bilateral orbits - sagittal T2. Page 14 of 45

15 Fig. 8: Inflammatory pseudotumour bilateral orbits - Axial CT. Page 15 of 45

16 Fig. 9: Inflammatory pseudotumour bilateral orbits - Axial CT. Page 16 of 45

17 Fig. 10: Orbital lymphoma - coronal T1. Page 17 of 45

18 Fig. 11: Orbital lymphoma - coronal T1 post Gado Page 18 of 45

19 Fig. 12: Orbital lymphoma - coronal T2. Page 19 of 45

20 Fig. 13: : right optic nerve glioma. Page 20 of 45

21 Fig. 14: right optic nerve glioma-sagittal T1. Page 21 of 45

22 Fig. 15: right optic nerve glioma- coronal T1. Page 22 of 45

23 Fig. 16: right optic nerve glioma -sagittal T1. Page 23 of 45

24 Fig. 17: spheno orbital meningioma - axial T1 FS +GADO. Page 24 of 45

25 Fig. 18: spheno orbital meningioma- axial T1 FS +GADO. Page 25 of 45

26 Fig. 19: spheno orbital meningioma-coronal T1 FS +GADO. Page 26 of 45

27 Fig. 20: retinoblastoma- axial T1 Page 27 of 45

28 Fig. 21: retinoblastoma - axial T2. Page 28 of 45

29 Fig. 22: retinoblastoma_axial T1 FS GADO. Page 29 of 45

30 Fig. 23: orbital hydatid cyst -axial T2. Page 30 of 45

31 Fig. 24: orbital hydatid cyst-axial T1. Page 31 of 45

32 Fig. 25: orbital hydatid cyst- axial T1 GADO. Page 32 of 45

33 Fig. 26: fibrous dysplasia. Page 33 of 45

34 Fig. 27: fibrous dysplasia-coronal T2. Page 34 of 45

35 Fig. 28: fibrous dysplasia- coronal T1 Page 35 of 45

36 Fig. 29: fibrous dysplasia-coronal T1 GADO. Page 36 of 45

37 Fig. 30: choroidal melanoma-axial T1. Page 37 of 45

38 Fig. 31: choroidal melanoma-axial T1 FS GADO. Page 38 of 45

39 Fig. 32: choroidal melanoma-axial T2 Page 39 of 45

40 Fig. 33: rhabdomyosarcoma- axial T1 Page 40 of 45

41 Fig. 34: rhabdomyosarcoma- axial T 1 FS GADO Page 41 of 45

42 Fig. 35: rhabdomyosarcoma -axial T2. Page 42 of 45

43 Fig. 36: rhabdomyosarcoma-coronal T1 Page 43 of 45

44 Conclusion The possible etiologies of orbital masses are numerous, and arriving at the correct imaging and clinical diagnosis can be challenging as a result. A working familiarity of the expected imaging appearance of common orbital masses can greatly inform the appropriate subsequent management of the patient and help prevent unnecessary procedures. The comprehensive pictorial review aims to provide the practicing radiologist a summary of the imaging diagnostic criteria for this clinically significant diagnosis. Page 44 of 45

45 References 1. Kapur R, Sepahdari AR, Mafee MF, et al. MR imaging of orbital in#ammatory syndrome, orbital cellulitis, and orbital lymphoid lesions: the role of diffusion-weighted imaging. AJNR Am J Neuroradiol 2009;30(1): Uehara F, Ohba N. Diagnostic imaging in patients with orbital cellulitis and in#ammatory pseudotumor. Int Ophthalmol Clin 2002;42(1): Som P, Curtin H. Head and neck imaging; Yuen SJ, Rubin PA. Idiopathic orbital in#ammation: distribution, clinical features, and treatment outcome. Archiv Ophthalmol 2003;121(4): Page 45 of 45