ROLE OF ULTRASOUND IN EVALUATING OCULAR AND ORBITAL DISEASES

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1 TJPRC: Journal of Ophthalmic Surgery and Ocular Pharmacology (TJPRC: JOSOP) Vol. 1, Issue 1, Dec 2016, 1-14 TJPRC Pvt. Ltd. ROLE OF ULTRASOUND IN EVALUATING OCULAR AND ORBITAL DISEASES ZAIN IRFAN KHATIB 1 & SEETHALAKSHMI D K 2 1 M. S. Ophthalmology, Ophthalmology, Karnataka Institute of Medical Sciences, Hubli, Karnataka, India 2 Assistant Professor, Department of Ophthalmology, Karnataka Institute of Medical Sciences, Hubli, Karnataka, India ABSTRACT Purpose The aim of the present study is to establish the role of B-scan Ultrasonography in: assessing the posterior segment of eye in presence of opaque media and evaluating specific posterior segment ocular abnormalities even in the presence of clear media, as and when indicated. For orbital leiosns, in evaluating the orbital tissue to assist in the diagnosis of proptosis and assessing orbital tumour location, configuration, extent and relationship to adjacent structures. Materials and Methods A prospective cross sectional study was conducted between January 2014 to November 2015 on 71 eyes of 62 patients presenting to outpatient department of KIMS, Hubli. B-scan Ultrasound (with A-scan overlay) was performed with a 12 Mhz probe. Results The overall sensitivity, specificity and accuracy of ultrasonography for diagnosing ocular lesions was 93.1%, 97.14% and 94.62% (P value < ) compared to 50.0%, 97.14% and 67.74% for clinical examination respectively. The sensitivity, specificity and accuracy of ultrasonography for diagnosing orbital lesions was 82.60%, 97.14% and 93.55% (P value < ) respectively Original Article Interpretation and Conclusions B- scan ultrasonography was the initial imaging modality opted in most of the cases as it was readily available, simple, cost effective, non ionizing, non invasive and reliable modality. It has a higher spatial and temporal resolution compared to both CT and MRI for the diagnosis of ocular pathologies. It superseded the accuracy of ophthalmoscopy in the diagnosis of posterior segment ocular pathologies with significant difference (p-value < ). However in certain orbital pathologies; for the evaluation of bony involvement, extension to adjacent structures and intracranial extensions, further evaluation with higher cross sectional imaging modalities (CT, MRI, Histopathology) were indicated. Sonological diagnosis correlated very well with the final diagnosis and formed a major basis for management decisions in significant number of cases. KEYWORDS: Ultrasonography, B- Scan, Echo, Ocular, Orbital, CT, MRI, Histopathology Received: Jul 22, 2016; Accepted: Aug 18, 2016; Published: Aug 30, 2016; Paper Id.: TJPRC:JOSOPDEC20161 INTRODUCTION B - scan (brightness scan) is a real time 2 dimensional ultrasonography of the eye and orbit and is non hazardous, atraumatic and invaluable in the evaluation of orbito-ocular lesions, especially in the presence of opaque media when there is a suspicion of an intraocular mass. [1]

2 2 Zain Irfan Khatib & Seethalakshmi D K A-scan (amplitude scan) is a one-dimensional ultrasound and when combined with b-scan, it provides quantitative data on the b-scan echoes (B-scan ultrasound with A-scan overlay). Vitreoretinal diseases are the most common indication for ultrasonographic imaging of the posterior segment. Although most conditions of the posterior segment can be viewed directly, in situations where there is media opacity (e.g., because of vitreous haemorrhage), echography allows for evaluation of the vitreous, retina and choroid that otherwise would be impossible. Using ultrasound, it is possible to identify, evaluate, and follow numerous posterior segment conditions. [2] Because of its ability to evaluate eyes using either clear or opaque media, ultrasonography has been a critical adjunct in ophthalmology for more than 50 years in case of ocular inflammatory disorders. [3] Ultrasound is the best method for the exploration of the eyeball. Pre-extraocular lens work up, intraocular foreign body localization, evaluation of vitreoretinal disorders, and diagnosis and follow up of ocular tumours, are best achieved by ultrasound. Ultrasound is also of great help in the assessment of the orbit, outside the globe. [4] MRI and CT of the retro orbital structures have several advantages over ultrasound, including high resolution images with thin sections, magnification techniques, and the capability for image reconstruction in multiple planes. These modalities demonstrate lesions in the posterior and apical part of the orbit, and adjacent sinuses and intracranial structures. For these reasons, MRI and CT are now the imaging modalities of choice in investigating orbital diseases. Their disadvantages include, the delivery of radiation dose to the eye with CT; subtle lesions of the optic nerve are missed; and the examination may be time consuming. Ultrasound has the advantage of rapidity and accessibility and, with its ability to identify the orbital walls, optic nerve, extra ocular muscles and orbital masses, it is a useful first line investigation in proptosis. [5] OBJECTIVES OF THE STUDY The aim of the present study is to establish the role of B-scan Ultrasonography in: Assessing the posterior segment of eye in presence of opaque media. Evaluating specific posterior segment ocular abnormalities even in the presence of clear media, as and when indicated. Evaluating the orbital tissue to assist in the diagnosis of proptosis. Assessing orbital tumour location, configuration, extent and relationship to adjacent structures. MATERIALS AND METHODS Source of Data Data was collected from all patients presenting with proptosis, symptoms suggestive of orbital lesions, and posterior segment ocular lesions to the ophthalmology OPD, Karnataka Institute of Medical Sciences, Hubli between January 2014 and November Method of Collection of Data A prospective correlational study was conducted over a period of two years (January 2014 to Novemeber 2015) on 71 eyes of 62 patients with symptoms related to eye and orbit. The patients were evaluated with high resolution Ultrasonography using a 12 MHz probe. The ultrasonographic diagnoses were correlated with the clinical and laboratory

3 Role of Ultrasound in Evaluating Ocular and Orbital Diseases 3 findings. Correlation with advanced imaging modalities (CT / MRI) and surgery with histopathology were done as necessary. Inclusion Criteria Patients clinically suspected to have orbital lesions, and all patients presenting with proptosis Patients presenting with opaque media, to rule out posterior segment ocular abnormalities. Patients presenting with clear media, in whom ultrasound was indicated. Exclusion Criteria: Patients with open globe injuries were excluded from the study. Technique of Sonographic Study With the patient in supine position, Ultrasound was performed with closed eyelid after application of coupling gel utilizing contact method. Linear high frequency probe (12MHz) of Appasamy Associates ultrasound system was used for the study. Longitudinal, transverse and axial scans were performed, both in static and with dynamic movements of eye after instructing the patients. Ultrasonographic diagnosis was made based on various acoustic characteristics studied in conjunction with clinical data. Higher imaging modalities (CT/ MRI) were employed where necessary and findings were correlated with ultrasonographic diagnosis. Surgery with histopathological correlation was done as applicable. Final diagnosis were made based on these findings and compared with the ultrasonographic diagnosis. RESULTS We included a total of 62 patients in our study group (Table 1: Distribution). Table 1: Distribution of Patients No of Patients No of Eyes Ocular pathologies Orbital pathologies Total Table 2: Distribution of Ocular Pathologies Pathologies Number of Cases Rhegmatogenous Retinal Detachment 15 Proliferative Vitreoretinopathy 8 Vitreous Haemorrhage 7 Tractional Retinal Detachment 4 Posterior Vitreous Detachment 3 Lens dislocated in vitreous 3 Choroidal Detachment 2 Intraocular Foreign body (Posterior segment) 2 Posterior staphyloma 2 Endophthalmitis 2 Exudative Retinal Detachment 1 Globe size abnormality - Nanophthalmos 1 Asteroid Hyalosis 1 Choroidal melanoma 1

4 4 Zain Irfan Khatib & Seethalakshmi D K Table 3: Distribution of Orbital Pathologies Pathologies No of Patients No of Eyes Thyroid Orbitopathy 3 6 Orbital Lymphoma 2 2 Cavernous Hemangioma 2 2 Dermoid Cyst 2 2 Maxillary sinus carcinoma 1 1 Schwannoma 1 1 Optic nerve meningioma 1 1 Ethmoidal sinus mucocoele 1 1 Langerhan cell Histiocytosis 1 1 Microphthalmos with orbital cyst 1 1 Orbital Myocysticercosis 1 1 Orbital Pseudotumour 1 1 Epidermal nevus syndrome 1 1 Subperiosteal abscess 1 1 Retrobulbar optic nerve thickening and calcification 1 1 Out of all the ocular pathologies in our study group (Table 2), the maximum detected were Rhegmatogenous retinal detachments (29%) followed by Proliferative vitreoretinopathy (15%) and Vitreous haemorrhage (13%). All orbital pathologies in our study (Table 3) were unilateral, except for 3 patients with Thyroid eye disease, all of which were bilateral (6 eyes). In all the orbital cases, a detailed orbital B-scan ultrasound with A-scan overlay was performed with the transverse, longitudinal and axial probe positions depending on the site of the suspected lesion. ultrasound findings were correlated with clinical history, examination, and other investigation modalities like CT, MRI and histopathology to come to a final diagnosis. Among patients with ocular pathologies, the maximum percentage of patients were in the years and years age groups (30% each). There was a gender inequality with 27 males as compared to 15 females. Among the individual pathologies, patients with VH were maximum in the 41 to 60 years age group and with a 85% male predominance. In comparision, RRD and PVR patients were predominantly seen in the 26 to 40 years age group and with an almost equal gender distribution. Most TRD patients were also seen in the 41 to 60 years age group with a male predominance similar to VH. This was due to the fact that most of the patients with VH also had TRD and versa due to a common entity being Diabetic retinopathy and its related complications which included both VH and TRD. IOFB was seen in 2 cases, both being in middle aged males due to occupation related risks. Most of the patients with orbital pathologies were in the 11 to 25 years age group (30%) followed by >60 years age group (25%). There was almost equal gender distribution with 11 patients being males (55%) and 9 females (45%). Out of the 20 patients, 17 had unilateral pathologies, with 5 being right sided, and 12 being left sided. Bilateral orbits were involved in 3 patients. For orbital lesions, Purnell first described ultrasound B scan patterns that have been reclassified into four general diagnostic patterns: ACOUSTICALLY CYSTIC TUMOURS: Rounded regular outline Good acoustic transmission

5 Role of Ultrasound in Evaluating Ocular and Orbital Diseases 5 Sharp definition Good demarcation Rounded anterior border Posterior extent of tumour and outline well demonstrated ACOUSTICALLY SOLID TUMOURS: Rounded regular outline Poor acoustic transmission / high acoustic absorption Multiple internal echoes (echogenic interfaces) Sharply defined anterior border Relatively well demarcated Acoustic homogeneity ACOUSTICALLY ANGIOMATOUS TUMOURS: Irregular outline Good sound transmission Non encapsulated Diffuse with numerous finger like projections into retrobulbar fat pattern Acoustically well demarcated Definite acoustic hollowness Posterior extent well outlined Pulsatile flow on Doppler interrogation ACOUSTICALLY INFILTRATIVE TUMOURS: Highly irregular outline Very poor sound transmission Non encapsulated Poorly demarcated Scalloped / lobulated outline Acoustic solidity and homogeneity Posterior extent not delineable Localized flow in these lesions in all areas of orbit

6 6 Zain Irfan Khatib & Seethalakshmi D K Pathologies Orbital Lymphoma Cavernous Hemangioma Dermoid Cyst Maxillary sinus carcinoma Schwannoma Optic nerve meningioma Ethmoidal sinus mucocoele Langerhan cell Histiocytosis Microphthalmos with orbital cyst Orbital Myocysticercosis Subperiosteal abscess Table 4: Acoustic Classification of Orbital Masses Acoustically Cystic Acoustically Solid Acoustically Angiomatous Acoustically Infiltrative Atypical Pattern We divided the orbital masses were divided into four categories based on the various acoustic charecteristics as described earlier (Table 4). In our study, the masses which predominantly followed the acoustically cystic pattern were Cavernous hemangioma, Ethmoidal sinus mucocoele, Langerhan cell histiocytosis, Microphthalmos with orbital cyst, and subperiosteal abscess. Acoustically solid masses were Maxillary sinus carcinoma and Schwannoma. Acoustically infiltrative masses were orbital lymphoma and Optic nerve meningioma. There were no masses fitting the angiomatous group in our study. 2 masses which did not fit any of these 4 patterns were Dermoid cyst and orbital myocysticercosis. Dermoid cyst showed well defined anterior and posterior borders, but unlike other cystic lesions, had very high internal echoes due to its tissue heterogeneity. Myocysticercosis of the inferior rectus muscle showed a large cyst like enlargement of the muscle with well defined borders, but in the internal structure its showed a central high reflective echo due to the scolex. Hence these 2 lesions were grouped separately as an atypical pattern. Table 5: Ocular Pathologies: Ophthalmoscopic Vs Ultrasound Diagnosis No of Patients Ophthalmoscopic diagnosis Diagnosis missed on Ophthalmoscopy Ultrsonographic Diagnosis Diagnosis Missed on USG RRD TRD ERD CD PVD PVR Post Staph IOFB Lens in vitreous Endoph Asteroid Nanoph VH Ch Mel Retinal Breaks Total

7 Role of Ultrasound in Evaluating Ocular and Orbital Diseases 7 Out of the 58 pathologies studied, almost all of them were diagnosed on ultrasound (54 out of 58). Only four cases of retinal tears were missed on ultrasound that were diagnosed clinically (Table 5). Thus, the sensitivity of ultrasound to diagnose posterior segment ocular pathologies was 93.1% as compared to 50% sensitivity of ophthalmoscopic diagnosis. Table 6: Orbital Pathologies: Ultrasound Vs Other Investigation Modalities Pathologies Number of Cases Lesions Picked up by USG Lesions Missed on USG Thyroid Orbitopathy Orbital Lymphoma Cavernous Hemangioma Dermoid Cyst Maxillary sinus carcinoma Schwannoma Optic nerve meningioma Ethmoidal sinus mucocoele Langerhan cell Histiocytosis Microphthalmos with orbital cyst Orbital Myocysticercosis Orbital Pseudotumour Epidermal nevus syndrome Subperiosteal abscess Retrobulbar optic nerve Diagnosis Made with Other Relevant Investigations (CT, MRI, Histopath) thickening and calcification Total Out of the 23 orbital pathologies studied, 19 of them could be picked up on B-scan ultrasound with A-scan overlay (Table 6). The other 4 lesions that were not picked up on ultrasound included 2 eyes of thyroid related proptosis, 1 case of orbital pseudotumour, and 1 case of eyelid nevus (as part of epidermal nevus syndrome). These lesions were diagnosed with other investigations like CT, MRI and histopathology. Out of the 19 cases that were detected on ultrasound, 3 of them were diagnosed based on the ultrasound and clinical findings without needing any other investigations. These included 2 cases of dermoid cyst, and 1 case of orbital myocysticercosis. For the remaining 16 cases, ultrasound findings were correlated with CT, MRI and/or histopathology findings to make a final diagnosis. Based on these findings, the sensitivity of ultrasound to pick up orbital lesions was 82.6%. Table 7: Ultrasound Diagnosis for Ocular Vs Orbital Pathologies Parameter Ultrasound Diagnosis Ocular Orbital SENSITIVITY 93.1% 82.6% SPECIFICITY 97.14% 97.14% PPV 98.18% 90.47% NPV 89.47% 94.44% ACCURACY 94.62% 93.54% p - VALUE < < Statistical Methods: Descriptive statistical analysis has been carried out in the present study. Results on continuous measurements are presented on Mean+/- SD (Min-Max) and results on categorical measurements are presented in Number (%). Significance is assessed at 5% level of significance. Fisher Exact test has been used to find the significance of association of Sonological diagnosis with final diagnosis. Diagnostic statistics such as sensitivity, Specificity, PPV, NPV

8 8 Zain Irfan Khatib & Seethalakshmi D K and Accuracy has been used to find the correlation of CT scan with final diagnosis. Overall ultrasonography has a reasonably high sensitivity and specificity with a high diagnostic accuracy in the diagnosis of both ocular and orbital lesions (Table 7) DISCUSSIONS In our study, we evaluated a total 72 eyes of 61 patients with ocular and orbital diseases over a period of two years. Out of these, 48 eyes of 42 patients had ocular pathologies, while 23 eyes of 20 patients had orbital pathologies. Our study group included a wide range of patients with ocular and orbital pathologies with age ranging between 1 month and 70 years, with most of the patients being in the 5 th and 6 th decade. There was a gender slight inequality in our study with a male to female ratio of 1.45:1. Out of 62 patients, 9 had bilateral involvement, 22 had right side and 31 had left side involvement. The most common indication for sonographic examination was 'presence of opaque media' (37%), followed by 'for evaluation of posterior segment pathology in presence of clear media' (32%). 'Proptosis' was the third most common indication for ultrasound evaluation (27%), while mass in orbit constituted just 4% of the indications for ultrasound evaluation. Out of the 48 eyes with ocular pathologies that we studied, there were a total of 58 posterior segment lesions that were evaluated using clinical methods and ultrasound. Out of these, only 29 lesions were correctly diagnosed clinically with ophthalmoscopic examination, while the other 29 lesions were missed. In contrast, ultrasound was able to correctly diagnose 54 out of the 58 lesions, with 4 retinal tears being missed on ultrasound that were diagnosed on ophthalmoscopy. The overall sensitivity, specificity, PPV, NPV and accuracy of ultrasound for the diagnosis of ocular pathologies were 93.1 %, %, %, % and % (p- value < ) respectively compared to 50.0 %, %, %, % and % for ophthalmoscopic examination. There were a total of 20 patients with orbital diseases that were included in the study group. Most of the lesions were unilateral, except for three cases of thyroid orbitopathy which included both eyes, so a total of 23 eyes from the 20 patients were evaluated. Most of the lesions that lesions could be picked up on B-scan ultrasound because most orbital masses are less heterogenous than surrounding orbital tissue, thus having smaller echoes as compared to orbital tissue. Based on their acoustic characteristics they were classified as acoustically cystic, solid, angiomatous or infiltrative. Also, in our study we found that ultrasound B-scan was very effective in picking up early subtle thickening of extraocular muscles in cases of Thyroid eye disease, which could be missed on CT scan and MRI. By using the measurement guide, the exact thickness of the muscle belly could be measured on transverse and longitudinal scans, and correlated with the normal values. Out of the 23 lesions that were evaluated, 17 of them were picked up on ultrasound evaluation, and diagnosis was made after correlating with other investigations like CT scan MRI and histopathology (FNAC, incision or excision biopsy). Three lesions (1 case of orbital myocysticercosis and 2 cases of dermoid cyst), were directly diagnosed based on ultrasound findings without needing any further investigations.

9 Role of Ultrasound in Evaluating Ocular and Orbital Diseases 9 Four lesions (1 case of orbital pseudotumour, 1 case of eyelid nevus, and 1 case of thyroid eye disease with bilateral involvement) were missed on ultrasound evaluation but subsequently diagnosed with the other investigation modalities mentioned above. The overall sensitivity, specificity, PPV, NPV and accuracy of ultrasound for the diagnosis of orbital pathologies were %, %, 90.47%, % and % respectively with a p- value < OCULAR PATHOLOGIES Retinal Detachment: In our study, we had a total of 28 cases of retinal detachments, out of which there were 15 cases of pure RRD, 8 cases of RRD with PVR, 4 cases of TRD, and 1 case of ERD. Ultrasound was 100% sensitive in diagnosing all types of retinal detachments, and was the most common imaging modality to pick up retinal detachment in presence of opaque media. Even in the presence of clear media, it was useful to confirm the diagnosis and differentiate between the different types of retinal detachments. Pure RRD: These cases typically were attached to the optic nerve head, and had a concave configuration, unless it was a bullous RD. There were 3 cases of bullous RD associated with giant retinal tears where the configuration of RD was convex and mobile on kinetic echography (Figure 1). RRD with PVR: These cases of RD typically were fixed with no movement and showed a classical funnel shaped appearance (open or closed funnel), sometimes associated with intraretinal cysts (Figure 4). TRD: These cases were associated mostly with VH, and showed a typical tented up appearance and showed PVD attached to multiple points on the retina causing traction ERD: The single case of ERD in our study was a case of Sturge Weber syndrome having a typical convex RD, with shifting fluid along with choroidoscleral thickening suggestive of ERD. Vitreous Haemorrhage: We had 7 cases of VH in our study, and all were diagnosed with ultrasound, adjusting the gain as per need. It showed multiple high reflective echoes in vitreous cavity mostly in posterior inferior part of vitreous, and commonly associated with TRD. Posterior Vitreous Detachment: All 3 cases of PVD in our study were diagnosed on ultrasound. PVD showed a low to medium reflective membranous echoes in the vitreous cavity with freely undulating after movements on kinetic echography. Choroidal Detachment: We had 2 cases of choroidal detachment, 1 case was due to post op hypotony and other due to uveal effusion associated with Sturge Weber syndrome. CD showed a high reflective membranous echo with convex configuration and which does not extend posteriorly beyond vortex vein attachment. Intraocular Foreign Body: 2 cases of IOFB, both seen in young males in 3 rd decade were easily picked up on ultrasound. Both cases were diagnosed clinically but diagnosis was confirmed by ultrasound which showed a characteristic very high reflective echo with posterior orbital shadowing. Endophthalmitis: We has 2 cases, both showed the same findings of multiple low to moderate reflective echoes filling the entire vitreous cavity along with choroido-scleral thickening. Lens in Vitreous: In our study, we had 3 cases of blunt trauma associated with complete displacement of lens the

10 10 Zain Irfan Khatib & Seethalakshmi D K vitreous cavity. On ultrasound it appeared as a large IOFB with two high spikes on A-scan corresponding to the anterior and posterior lens capsule. Posterior Staphyloma: Both cases of posterior staphyloma in our study were missed on clinical examination but diagnosed on ultrasound as a dome shaped excavation in the posterior coats of the eye, with an increased axial length. Asteroid Hyalosis: We had a single case of Asteroid Hyalosis in a diabetic patient, which typically showed the vitreous cavity filled with multiple highly reflective echoes, with a clear thin zone between the lesion and the retina. Choroidal melanoma: We had 1 case of choroidal melanoma of a lady presenting in the 5 th decade, with a subclinical lesion in the periphery showing the typical collar stud appearance with internal homogeneity. Nanophthalmos: This patient was a middle aged man having high hypermetropia with one eye significant optic disc cupping and the other eye having pseudopapillitis on ophthalmoscopic examination. On performing ultrasound, there was reduced axial length of both eyes (18mm), thus making a diagnosis of bilateral nanophthalmos with high hypermetropia and unilateral glaucoma. Orbital Pathologies Thyroid Orbitopathy: In our study, we had 3 cases of thyroid orbitopathy, all 3 cases having bilateral proptosis, so a total of 6 eyes were studied. In 2 patients, B-scan ultrasound was able to pick up extraocular muscle thickening which correlated with the CT scan findings. In the other case, we were not able to pick up the cause of proptosis on ultrasound, but CT scan showed generalized thickening of orbital soft tissue. Orbital Lymphoma: We had to patients diagnosed to have orbital Lymphoma, both were elderly males presenting with a gradual onset painless proptosis. In one case, ultrasound findings showed the presence of a large mass of low reflective echoes whose posterior extent could not be visualized, and compressing the globe from all sides. The other case on ultrasound showed a large mass in the infero-medial orbit with well defined anterior border and posterior extent visualized, with internal structure showing heterogenous medium reflective echoes (Figure 2B). CT scan and histopathology for both cases later confirmed the diagnosis as Lymphoma. Dermoid Cyst: 2 cases of dermoid cyst were diagnosed in our study, both were females in their 2 nd decade presenting with a mass in their superolateral orbits. A para-ocular scan was done for both cases directly over the lesion. They showed a characteristic pattern on ultrasound, having well defined anterior and posterior borders and high internal echoes due to the heterogeneous internal structure. The diagnosis was made based on ultrasound findings, and no additional investigation was needed. Cavernous Hemangioma: There were 2 cases diagnosed, one patient being in the 2 nd decade while other was an older patient in 7 th decade. Both patients presented with an axial proptosis, slow growing and painless. On ultrasound, both showed an intraconal mass with sharp anterior border, medium reflective internal echoes, and ill defined posterior border due to tissue shadowing effect. CT, MRI and histopathology confirmed the final diagnosis. Orbital Myocysticercosis: A young female patient presented with sudden onset proptosis with pain since 15 days. Ultrasound showed a large well defined mass in the inferior quadrant with well defined anterior and posterior borders, and a large central echo probably suggestive of a scolex (Figure 3). A course of Albendazole and oral steroids was given for 1 month, and the lesion completely resolved.

11 Role of Ultrasound in Evaluating Ocular and Orbital Diseases 11 Microphthalmos with Orbital Cyst: A 9 year old female presented with loss of vision since birth along with proptosis in right eye. On examination, features suggestive of microphthalmos were present, and on ultrasound, a large echolucent cavity with well defined borders in the inferomedial quadrant was seen. There was also reduced axial length of 18mm, which confirmed the diagnosis of microphthalmos with orbital cyst. Ethmoidal Sinus Mucocoele: A 54 year old male presented with left eye proptosis of 10 days without visual loss. On ultrasound, an illdefined hypoechoic lesion was seen in the medial orbital cavity extending into the retrobulbar space, posterior extent could not be made out. CT scan of paranasal sinuses confirmed the diagnosis and an endonasal ethmoidal exploration was planned. Maxillary Sinus Carcinoma: A 12 year old boy presented with proptosis in left eye since 2 months associated with pain and recent onset decrease of vision. A large hypoechoic lesion about 16mm in thickness, anterior border well defined, posterior border ill defined, involving medial, inferior and retro-orbital spaces, obliterating the optic nerve shadow (Figure 2A). CT scan and endonasal biopsy confirmed it to be a carcinoma arising from the maxillary sinus. Optic Nerve Sheath Glioma: A 62 year old male presented with 6 months history of right eye proptosis with pain and decreased vision since 1 month. Fundus showed optociliary shunt vessels and optic atrophyin the involved eye. Ultrasound showed an ill defined, moderate echogenic lesion in the intraconal space obliterating the optic nerve shadow. CT scan and MRI confirmed the diagnosis to be optic nerve sheath meningioma, and an excisional biopsy was planned. Langerhan Cell Histiocytosis (Eosinophilic Granuloma): A 3 year old female child presented wit left eye gradual proptosis since 1 year. Ultrasound showed a well defined echolucent mass in the superotemporal orbit with sharp borders. A differential diagnosis was given based on these findings. Complete blood counts showing eosinophilia and FNAC confirmed the diagnosis and surgical excision was planned. Schwannoma: A 45 year old male presented with 2 years history of left eye gradual painless proptosis with no visual loss, fundus showing optic disc edema. On ultrasound, a large hypoechoic mass was seen in retrobulbar and superior orbital cavity, measuring horizontally 16 mm, while vertical extent could not be estimated superiorly. Lesions was having slight irregular internal pattern, and optic nerve shadow was obliterated. CT scan and histopathology confirmed it to be a schwannoma arising from one of the branches of ophthalmic nerve in the superior orbit. Epidermal Nevus Syndrome (Nevus of Eyelid): A four year old female presented with a painless mass in the upper eyelid since birth. On examination, the mass was pigmented, illdefined, and causing mechanical ptosis. An ultrasound direct para-ocualar scan was performed, but did not reveal any significant findings. A histopathologocal FNAC revealed it to be a benign eyelid nevus as part of epidermal nevus syndrome. Reterobulbar Optic Nerve Thickening: A 30 year old female presented with 2 years sudden onset decrease of vision in left eye. Fundus showed a pale optic disc. Bscan ultrasound showed a thickened optic nerve shadow with some irregular echoes as compared to the right eye. CT scan confirmed the diagnosis showing a thickened and calcified retrobulbar optic nerve probably due to old inflammation. Orbital pseudotumour (Idiopathic orbital inflammatory disease): A 40 year old male presented with 6 months history of proptosis associated with pain since 3 months. Ultrasound examination did not reveal any significant findings. CT scan showed an irregular illdefined lesion in the retro-orbital cavity. A course of oral steroids was given for 1 month and the patients symptoms resolved, thus making the most likely diagnosis as pseudotumour of orbit.

12 12 Zain Irfan Khatib & Seethalakshmi D K CONCLUSIONS Most of the ocular pathologies our study group were in the 4 th and 5 th decade and there was a gender inequality with a male to female ratio of 1.8:1. The right and left eyes were almost equally affected (45% and 41% respectively) with 14% bilateral involvement. Most of orbital pathologies were seen in the 11 to 25 year age group (30%), with a near uniform gender predilection (M:F: 1:1.2). There was a predilection for involvement of left eye (60%) as compared to right eye (25%) and 15% showed bilateral involvement. The most common indication for ultrasound evaluation was opaque media (37%), followed by posterior segment evaluation in clear media (32%), followed by proptosis (27%), and lastly, mass in orbit (4%). The most common ocular pathology in our study was rhegmatogenous retinal detachment, followed by proliferative vitreoretinopathy. The most common orbital pathology was thyroid orbitopathy, followed by cavernous hemangioma. orbital lymphoma and dermoid cyst. The overall sensitivity, specificity, PPV, NPV and accuracy of ultrasound for the diagnosis of ocular pathologies were 93.1 %, %, %, % and % (p- value < ) respectively compared to 50.0 %, %, %, % and % for ophthalmoscopic examination. The overall sensitivity, specificity, PPV, NPV and accuracy of ultrasound for the diagnosis of extraocular pathologies were %, %, 90.47%, % and % respectively with a p- value < Ultrasonography is readily available, simple, cost effective, non ionizing, non invasive and a reliable imaging modality for posterior segment ocular pathologies. It readily establishes the diagnosis in significant number of cases. It has a higher spatial and temporal resolution compared to both CT and MRI for the diagnosis of ocular pathologies. It superseded the accuracy of ophthalmoscopic diagnosis with significant difference (p- value < ). Even though for most orbital pathologies, it needs additional investigations (CT, MRI, histopathology) for confirming the diagnosis, ultrasound proves a useful imaging tool and correlates very well with the final diagnosis. REFERENCES 1. Nzeh DA, Owoeye JFA, Ademola- Popoola DS, Uyanne I. Correlation of clinical and ultrasound findings in orbito- ocular disease using non- dedicated scanners: Experience at Ilorin, Nigeria. European Journal of Scientific Research 2007;3: Fu EX, Hayden BC, Singh AD. Intraocular tumors. Ultrasound Clin ; Sharma S, Ventura AACM, Waheed N. Vitroretinal disorders. Ultrasound Clin 2008; Ventura AACM, Hayden BC, Taban M, Lowder CY. Ocular inflammatory disorders. Ultrasound Clin 2008; Berges O, Lfitte F, Koskas P. The Orbit. In, Grainger RG, Allison D, Adam A, Dixon AK (ed). Diagnostic Radiology: A Textbook of Medical Imaging, 4 th edition. London, Churchill Livingstone, 2001; Clinical Ultrasound- Paul Allan, Grant Baxter, Michael J. Weston: The eye and orbit- John A. Feilding. 7. Fielding JA. The Eye. In, Meire HB, Cosgrove DO, Dewbury KC, Farrant P (ed). Clinical Ultrasound: A Comprehensive Text: Abdominal and General Ultrasound, 2 nd edition(2); Mcleod D, Restori M, Wright JE. Rapid B-scanning of the vitreous. Br J Ophthalmol 1977;61:

13 Role of Ultrasound in Evaluating Ocular and Orbital Diseases Mafee MF. Orbit: Embryology, Anatomy and Pathology. In, Som PM, Curtin HD (ed). Head and neck imaging, 4 th edition. New York, Mosby, 2003; Restori M, Mcleod D. Ultrasound in pre-vitrectomy assessment. Trans Ophthalmol Soc UK 1977; 97: Bedi DG, Gombos DS, Ng CS, Singh S. Sonography of the eye. AJR 2006;187: Sharma OP. Orbital sonography with its clinico- surgical correlation. Ind J Radiol Imag 2005; 15:4: APPENDICES Legends for Images FIGURE 1- A, B, C: Bullous rhegmatogenous retinal detachment due to giant retinal tears Figure 1- A, B, C: Bullous Rhegmatogenous Retinal Detachment Due to Giant Retinal Tears Figure 2 A: Lymphoma: Ill-Defined Borders and Irregular Pattern (Acoustically Infiltrative Tumour), B: Maxillary Sinus Tumour: Well Defined Anterior Border, with ill-defined Posterior Border Due to Significant Tissue Shadowning (Acoustically Solid Tumour)

14 14 Zain Irfan Khatib & Seethalakshmi D K Figure 3: Cysticercosis of Inferior Rectus Muscle A- Ultrasound Shows a Cyst Like well Defined Echolucent Lesion in Extraconal Space B- A high Reflective Echo in the Center of the Lesion can be seen, Suggestive of a Scolex C: MRI Shows Thickening of the Inferior Rectus Muscle Figure 4 A, B: Proliferative Vitreoretinopathy: A- Retinal Detachment with Multiple Intraretinal Cysts, B- Closed Funnel Retinal Detachment