Journal of Oral and Maxillofacial Radiology

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 9  |  Issue : 3  |  Page : 57--62

Predictive validity of ultrasonography for orbital lesions in a tertiary care teaching center in South India: A cross-sectional study


Karthikeyan Kannan, Naveen Durairaj 
 Department of Radiology, Dhanalakshmi Srinivasan Medical College and Hospital, Perambalur, Tamil Nadu, India

Correspondence Address:
Naveen Durairaj
Dhanlakshmi Srinivasan Medical College and Hospital, Siruvachur, Perambalur - 621 113, Tamil Nadu
India

Abstract

Background: The superficial location of the eye and its cystic composition make ultrasound ideal for imaging the eye. Ultrasonography (US) provides highly informative images and is a noninvasive, low-cost, and well-tolerated diagnostic technique. Aim: The present study was conducted to determine the predictive validity of ultrasonography in diagnosing orbital lesions. Materials and Methods: The study population consists of 85 patients with orbital lesions who attended the department of radiology and imaging during the study period. All clinical and ultrasound examinations were performed by a single investigator to identify ocular lesions. A linear high-frequency probe (5-9 MHz) of the LOGIQ P5 ultrasound system was used for the study. Histopathological and computed tomography (CT) and magnetic resonance imaging were used as applicable for final diagnosis. Diagnostic statistics such as sensitivity and specificity have been used to find the correlation of CT scan with the final diagnosis. coGuide was used for statistical analysis. Results: Out of 85 participants, 42 (49%) were male and the remaining 43 (51%) were female. Ultrasound showed an overall sensitivity, specificity, and accuracy of 94.2%, 98.8%, and 94.9% for ocular pathologies and 98.8%, 99.2%, and 95.2% for extraocular pathologies, respectively. Conclusion: US had overall high diagnostic validity and accuracy in localizing and characterizing orbital pathologies. Further evaluation with higher cross-sectional imaging modalities (CT) was indicated in certain cases; for the evaluation of bony involvement, extension to adjacent structures, and intracranial extensions.



How to cite this article:
Kannan K, Durairaj N. Predictive validity of ultrasonography for orbital lesions in a tertiary care teaching center in South India: A cross-sectional study.J Oral Maxillofac Radiol 2021;9:57-62


How to cite this URL:
Kannan K, Durairaj N. Predictive validity of ultrasonography for orbital lesions in a tertiary care teaching center in South India: A cross-sectional study. J Oral Maxillofac Radiol [serial online] 2021 [cited 2022 Aug 18 ];9:57-62
Available from: https://www.joomr.org/text.asp?2021/9/3/57/335734


Full Text



 Introduction



Orbital pathologies are a heterogeneous group of diseases with different clinical pictures, etiologies, and therapeutic management. Imaging plays a significant role in diagnosis and monitoring treatment for orbital pathologies due to poor clinical access to the orbits. Ultrasonography (US) is one such imaging modality.[1] The US of the ophthalmic region is performed to visualize intraocular and extraocular structures when the direct view of ocular periphery and fundus are impeded by opaque media or for axial length measurement before cataract surgery.[2]

The US provides highly informative images and is a noninvasive, low-cost, and well-tolerated diagnostic technique.[3] It is a procedure that depends on an operator's technical skill and expertise to achieve reliable results, thereby avoiding misdiagnosis. It has been used for the pathological assessment of orbital and ocular lesions.[4] The “cystic-like” anatomy of the eye act as an interface favorable for transduction of us and aids in the transformation of mechanical to an electronic signal, thereby allowing evaluation of different abnormalities of orbit, including tumor and tumor-like orbital masses.[5] It is useful for the evaluation of vitreous opacities such as inflammatory debris, synchysis scintillans, asteroid hyalinosis, membranes such as seen in vitreoretinal traction, and retinitis proliferates, organized blood, foreign bodies, etc., as an outpatient procedure.[6] A study has reported that the US showed an overall sensitivity, specificity, negative predictive value, and accuracy of 94.2%, 98.8%, 92.2%, and 94.9%, respectively, for ocular pathologies and 94.2%, 99.2%, 95.9%, and 95.2%, respectively, for extraocular pathologies.[7] Although the US can be very useful in the evaluation of the globe and its contents; its use is contraindicated if a ruptured globe is suspected.[6] Due to high temporal and spatial resolution, US contributes more to tissue diagnosis compared to computed tomography (CT) or magnetic resonance imaging (MRI).[8] It also aids in establishing kinetic properties of the tumors like vascularity (when used with color Doppler) and consistency.[9]

The brightness scan (B-scan) is two-dimensional US used to evaluate the eye and orbit. It is atraumatic, nonhazardous, and invaluable, allowing the evaluation of lesions in the presence of opaque media.[6] It is a cost-effective and very useful consideration, especially in the rural setting. To sum up, it is easily available, noninvasive, and produces reproducible results.[10] It can be performed without anesthetics or sedative therapy and in outdoor patients safely.[11] There was no literature available on the ultrasonographic diagnosis of orbital lesions in this region of the state. The present study was undertaken to evaluate the role of B-scan US in the evaluation of orbital abnormalities.

Objectives

To determine the predictive validity of the ultrasonographic diagnosis. To evaluate the sonographic findings in suspected ocular and extraocular lesions.

 Materials and Methods



Study population and study site

The study population consists of patients with clinically suspected orbital and ocular lesions attending the department of radiology and imaging, tertiary care hospital.

Inclusion criteria

Patients with clinically suspected orbital and ocular lesions.

All age groups and gender were included in the study.

Exclusion criteria

Patients with facial trauma:

Study design: Descriptive observational cross-sectional studySample size and Sampling technique: All the eligible 85 patients visited during the study period were recruited by convenient sampling till the sample size was obtainedStudy duration: 1 year and 6 months from January 2014 to June 2015Ethical considerations: The study was approved by the institutional review board and the ethics committee of the hospital and informed consent was obtained from each participant.

Data collection tools and clinical examination

Age, gender, presenting complaints of the patients were recorded. All clinical and ultrasound examinations were performed by a single investigator.

Ultrasonographic diagnosis

With the patient supine, ultrasound was performed with closed eyelid after applying coupling gel utilizing the contact method. A linear high-frequency probe (5-9 MHz) of the LOGIQ P5 ultrasound system was used for the study. Longitudinal and transverse axis scans were performed, both in static and with the dynamic movement of the eye after instructing the patients. The ultrasonographic diagnosis was made based on various acoustic characteristics studied in conjunction with clinical data.

Higher imaging modalities (CT/MRI) were employed where necessary. Surgery with histopathological correlation was done as applicable. Final diagnoses were made based on these findings and compared with the ultrasonographic diagnosis.

Statistical methods

Descriptive statistical analysis has been carried out in the present study. Results on continuous measurement are current on mean ± standard deviation (min–max), and effects on categorical measures are presented in number (%). Significance is assessed at 5%. Fisher's exact test has been used to find the importance of the association of sociological diagnosis with the final diagnosis. Diagnostic statistics such as sensitivity, specificity, and diagnostic accuracy have been used to find the correlation of CT scan with the definitive diagnosis. coGuide version V.1.0 was used for statistical analysis.[12]

 Results



A total of 85 patients were included in the final analysis.

Among the study population, 23 (27%) were aged <20 years, 42 (49%) were aged between 20–50 years and 20 (24%) were >50 years. Out of 85 participants, 42 (49%) were male and the remaining 43 (51%) were female. Bilateral lesions were seen in 15 patients (17%). The most common indication for ultrasound examination was proptosis followed by suspected orbital mass in our study [Table 1].{Table 1}

Out of 59 participants with ocular pathologies, the majority (18.64) % had vitreous haemorrhage (VH), followed by 11.86% had retinal detachment (RD), 10.17% had choroidal tumors and endophthalmitis for each, and 8.47% had retinoblastoma (RB). Out of 42 participants with extraocular pathologies, the majority of 16.67% had cysticercosis, followed by 14.28% had on tumors, 11.90% had hemangioma, and 9.52% had dermoid.[Table 2].{Table 2}

The sensitivity of US in detecting the ocular pathologies was promising (94.2%) except for VH and Choroidal elanoma (Ch me). Two cases of VH and one case out of four were missed in USG. An overall specificity and accuracy of 98.8% and 94.9%, respectively, were obtained for US in detecting the ocular pathologies [Table 3].{Table 3}

Out of 42 extraocular pathologies, 40 cases were correctly diagnosed by US. Out of five cases of hemangioma only one case was missed in US and one case of lymphoma out of three missed on ultrasonography, making an overall sensitivity to be 98.8%, specificity to be 99.2%, and accuracy (95.2) [Table 4].{Table 4}

 Discussion



Vitreous hemorrhage (18.63%) was the predominant ocular pathology found in the present study, followed by RD (11.86%). Cysticercosis (16.67%) was the common extraocular pathology followed by optic nerve tumors (14.28%). Ultrasound showed an overall sensitivity, specificity, and accuracy of 94.2%, 98.8%, and 94.9% for ocular pathologies and 98.8%, 99.2%, and 95.2% for extraocular pathologies, respectively.

Similar to the findings of the present study, VH was the most common lesion (22%), followed by RD (18%) among the intraocular lesions. In comparison, hematoma (10%) was the predominant extraocular lesion followed by dermoid (8%) in a study by Sambasivarao K et al.[6] Another study reported RD (26.7%) as the common intraocular pathology followed by cataract (20%) and cysticercosis (28.6%) as the major extraocular pathology, followed by cellulitis, conjunctival cyst, hemangioma, pleomorphic lacrimal gland adenoma, and squamous cell carcinoma (14.3%).[13] Sharma et al.[14] reported the common intraocular pathology followed by RD, whereas pseudotumor and Grave's orbitopathy formed predominant extraocular pathologies.

All the cases of ocular pathologies such as cataract, RD, posterior vitreous detachment, RB, choroid metastasis, choroid osteoma, scleritis, optic drusen, endophthalmitis, phthisis bulba, and chroma were correctly diagnosed by the US. Out of 11 cases, two cases of vitreous hemorrhage were missed on ultrasound due to improper adjustment of gain, with a sensitivity of 81.82%, specificity 100%, and accuracy of 96.61%. While in a previous study, all the cases were correctly identified in the US, with 100% sensitivity, 89.8% specificity, and 90.3% accuracy in diagnosing.[13] Another study reported 95% sensitivity, 99.4% specificity, and 81.8% accuracy in diagnosing VH in the US.[7]

Among the extraocular pathologies; pseudotumor, Grave's orbitopathy, myositis, cysticercosis, dermoid, dacryocystocele, mucocele, lacrimal gland pleomorphic adenoma, mucormycosis, arteriovenous malformation, sebaceous cell carcinoma, preseptal cellulitis with lid abscess, optic nerve tumors such as optic glioma, optic meningioma, and chloroma were correctly identified in the US. Out of the four choroidal melanoma cases, three cases were correctly diagnosed by the US, with a sensitivity, specificity, and accuracy of 75%, 100%, and 98.31%, respectively, in this study. While an earlier study reported a sensitivity, specificity, and accuracy of 87.5%, 99.5%, and 75%, respectively.[7] Sensitivity for lymphomas was 66.67% and specificity 100% in the present study. Similarly, a recent study reported a sensitivity of 67.5% for idiopathic orbital inflammation/lymphoma, while specificity was 82.65%.[15] Hemangioma showed a sensitivity of 80%, specificity of 100%, and accuracy of 97.62% in the US in this study. US was 100% sensitive, specific, and accurate in diagnosing hemangioma in a previous study.[13] Nagaraju et al. concluded hemangioma to be 75.9% sensitive and 99.5% clear.[7]

Nagaraju et al. noted the overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ultrasound for the diagnosis of ocular pathologies as 94.2%, 98.8%, 99.1%, 92.2%, and 94.9%, respectively, compared to 62.5%, 98.8%, 98.7%, 64.8%, and 62.7% for ophthalmoscopic examination.[7] Parchand et al. found the US to have an overall sensitivity and specificity of 92.31% and 98.31% for identification, localizing, and characterizing orbital pathologies.[16] An overall sensitivity, specificity, PPV, NPV, and accuracy of 95.5%, 100%, 100%, 77.8%, and 96.2%, respectively, were observed for the US by Choudhary et al.[13] Hafiz et al. found B scan the US to be significantly accurate in diagnosing orbital masses, including neoplastic and inflammatory conditions.[17] Dessì et al. concluded from the findings of their study that ophthalmic US is an important adjuvant for the clinical assessment of various ocular and orbital diseases.[18]

Proptosis (49.41%) was the common complaint in the present study, followed by complete vision loss (43.53%) and diminished or blurred vision (29.41%). Similarly, in a previous study, chief complaint was proptosis followed by total loss of sight.[7] The most common presenting complaint was the diminution of vision (40%), followed by ocular trauma (28%).[6] In another study, the chief complaint was diminished vision (21%), followed by trauma (14%).[13]

Limitations

The study was conducted in a single center which can affect the generalisability of the study. One of the limitations of the US is its high operator dependence, requiring skills and knowledge of trained personnel. There can be difficulty in performance in cases with gross proptosis. The US is also less sensitive for identifying calcification, bony involvement, extension to adjacent structures, and brain.

 Conclusion



Orbital US is a noninvasive diagnostic test with high sensitivity and specificity in detecting an orbital mass. Vitreous hemorrhage was the predominant ocular pathology, and cysticercosis was the common extraocular pathology found in the present study. Further evaluation with higher cross-sectional imaging modalities (CT) was indicated in certain cases; in assessing bony involvement, extension to adjacent structures, and intracranial extensions.

Acknowledgments

We acknowledge the technical support in data entry, analysis, and manuscript editing by “Evidencian Research Associates.”

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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