Role of Dacryoscintigraphy in the Management of Children with Epiphora

INTRODUCTION

Epiphora is a common clinical condition in ophthalmology, frequently encountered in daily practice. There are different causes for epiphora in the pediatric age group. It may result from either excessive tear production or obstruction of the lacrimal drainage system (LDS). Overproduction of tears can occur due to ocular irritation, such as from trichiasis or epiblepharon, inflammatory conditions such as keratitis or uveitis, allergies, or central nervous system related hypersecretion.^[1,2]

obstruction of the LDS is another major cause of epiphora in children. Among the various conditions leading to obstruction, congenital nasolacrimal duct (NLD) obstruction is the most common. In most children, this resolves spontaneously within the 1^st year of life without any intervention, though spontaneous resolution has also been reported up to 48 months of age. Lacrimal syringing (LS) and probing are typically reserved for children in whom spontaneous resolution does not occur.^[1]

Several diagnostic tests are available for evaluating children with epiphora, including LS, dacryocystography (DCG), and dacryoscintigraphy (DSG). Of these, LS is the most commonly used. However, it is invasive and can be risky and stressful in children. Furthermore, because it is not a physiological test, functional NLD obstruction, partial obstruction, and ductal stenosis may be missed.^[3]

DSG is a simple, noninvasive, and effective diagnostic tool for detecting abnormalities in the LDS that cause epiphora. DSG can identify abnormalities in nearly 80% of patients with epiphora symptoms despite a patent drainage system on syringing.^[4] It can also reveal abnormalities in asymptomatic individuals with a patent system. Advantages of DSG include its noninvasive nature, physiological relevance, safety, and use of low radiation doses.^[5]

DSG is particularly valuable in patients with epiphora and delayed tear film clearance who test “patent” on syringing. It is useful when NLD obstruction or stenosis is suspected, in cases of lacrimal pump failure, and for diagnosing functional lacrimal duct obstruction. In addition, it helps assess LDS patency after surgical intervention.^[5,6]

Although DSG has been studied extensively in adults, there are relatively few studies focusing on its diagnostic performance in the paediatric population with epiphora. This gap highlights the need for further evidence regarding its accuracy and clinical utility in children.

The goal of the present study was therefore to evaluate the diagnostic effectiveness of DSG in children with epiphora, find out demographic factors associated with epiphora, and assess treatment outcomes guided by DSG.

MATERIAL AND METHODS

This retrospective observational study was conducted at a tertiary care teaching institution, which serves a diverse patient population referred from various regions throughout the state.

Data for this study were collected between January 2022 and January 2024 from the Department of Nuclear Medicine at MNJ Institute of Oncology and Regional Cancer Hospital in Hyderabad. Children of both sexes aged 4–12 years who underwent DSG for the evaluation of epiphora were included.

The records of all previous DSG images were re-evaluated by two nuclear medicine physicians who were blinded to the clinical details of the children.

Eighty-one children with epiphora (38 boys and 43 girls; mean age, 7.7 ± 2.2 years; range from 4 to 12 years) were studied. None of the patients had a history of CNS-related hypersecretion, trichiasis, epiblepharon, clinical symptoms, or signs of conjunctivitis, craniofacial disorder, or trauma. Clinical history, treatment details, LS, and probing findings were collected from available case records. Out of 81 cases, 12 cases were excluded from the study due to inadequate clinical data, and a total of 69 cases (24 had bilateral and 45 had unilateral symptoms) were included in the study cohort.

DSG was performed in all children with technetium-99 m sodium pertechnetate radiopharmaceutical by using Infinia II VC Hawkeye single-photon emission computed tomography-computed tomography Gamma Camera, Wipro GE Healthcare Pvt Ltd.

Approximately two drops of 50 μCi/50 μl technetium-99 m sodium pertechnetate radiopharmaceutical in a saline solution are administered in the lateral portion of each eye in the supine position with an eyedropper. Child or parent instructed to blot tears with tissue and allow to drain down the excessive tears lateral aspect of the face to prevent the contamination of the face with radioactivity.^[7]

After instillation of radioactive eyedrops, the child is placed in a sitting position in front of the camera for imaging. The child was supported by adults or parents in order to maintain a sitting position and to limit the child movement during acquisition. We recorded dynamic images of both the eyes at same time with the use of a low-energy high-resolution collimator at 10 s/frame for 2 min followed by serial static images 1 min/frame at regular intervals for 5, 10, and 15 min. After 15 min static image, we encouraged all children to do nose blow/forceful sniffing (to create a negative pressure within the nose) or lacrimal sac massage (to reinforce the lacrimal pump) with the help of parents or attendants to enhance tear flow before acquiring 30 min static image to decrease false-positive results. Visualization of the nasolacrimal sac within 1 min with drainage of activity from the NLD into the nasal cavity within 10–15 min is considered a normal finding.^[7]

Pre sac obstruction defined as hold up of tracer at the inner canthus or failure of tracer to reach the lacrimal sac by the end of 2–3 min, pre duct/ductal obstruction defined as early filling of lacrimal sac but no sign of sac emptying on first static image at 5 min and Intra-duct obstruction defined as evidence of radiotracer in the upper part of the NLD at 5 min with no further drainage by 15 min.^[8] Based on the level obstruction on DSG and in correlation with findings of LS, children were treated with dilatation and probing for punctal block, conjunctival dacryocystorhinostomy (DCR) with stenting for common canalicular block, and Ductal obstruction (preductal/intraductal) cases were treated with DCR.

The data that has been collected and processed through the use of SPSS version 21, which was released by IBM, NY, USA Corp. in 2012. The results of this analysis have been expressed using descriptive statistics, including mean values with standard deviations, medians with interquartile ranges, and frequencies with corresponding percentages. Fisher’s exact tests were used wherever appropriate, and all P values were reported as corrected P values; and P < 0.05 was considered to be statistically significant.

RESULTS

A total of 138 eyes from 69 children with epiphora were examined, including 24 cases of bilateral and 45 cases of unilateral epiphora. The study also included 45 eyes (20 boys and 25 girls) without epiphora and 93 eyes (58 boys and 35 girls) with epiphora. There were no significant differences in sex distribution (P = 0.50) and age distribution (P = 0.70) between eyes with and without epiphora [Table 1]. DSG in 75 of 93 eyes with epiphora (80.7%) and 13 of 45 eyes without epiphora (28.9%) showed obstruction in the LDS. There was a statistically significant difference in duct obstruction between eyes with and without epiphora (P = 0.001) [Table 2]. Eighteen of 93 eyes with epiphora (19.3%) showed patency, and 32 of 45 eyes without epiphora (71.1%) showed patency, which was also statistically significant (P = 0.001) [Table 2].

DISCUSSION

DSG is a simple, safe, and noninvasive diagnostic test. It provides clear documentation of both physiological and pathological tear flow dynamics within the LDS. According to the literature, there are differing opinions regarding the diagnostic accuracy of DSG. The test is known for its good sensitivity but poor specificity; it may incorrectly identify healthy individuals as having LDS obstruction.^[9,10]

To address the issue of low specificity, various modified acquisition protocols for DSG have been introduced in recent years. These protocols include techniques such as nose blow/forceful sniffing (to create a negative pressure within the nose), lacrimal sac massage (to reinforce the lacrimal pump), exercise, and postwashing procedures. The goal of these modifications is to reduce the number of false positives and to improve the specificity of the test.^[10,11]

There are several other investigations available for diagnosing abnormalities in the LDS system in patients presenting with epiphora. DSG is considered equal to, or even superior to, other in-office tests such as the meniscus height test, LS, the Jones test, and the dye disappearance test. Studies have found good agreement between DSG and these office-based tests. ^{[12, 13]}

When compared to DCG, DSG provides less anatomical detail of the LDS. DCG is regarded as the most reliable test for pinpointing the site of obstruction. However, DCG is not a physiological test; it relies on hydrostatic pressure to widen the NLD artificially, which can result in false negatives. This limitation makes DCG less useful in cases of partial NLD obstruction, NLD stenosis, or functional NLD obstruction. Using both DCG and DSG together increases diagnostic accuracy, offering both anatomical and physiological information when evaluating patients with epiphora. DSG findings correlate well with patient symptoms. The test can detect abnormalities in the LDS in approximately 95% of symptomatic patients.^[14]

However, DSG does have several disadvantages. These include low specificity, limited ability to differentiate and localize anatomical obstructions, poor image resolution, and a lack of standardization in acquisition protocols.

There are varied opinions in the medical literature regarding the value of DSG in evaluating patients with epiphora. Some authors describe DSG as a highly useful procedure, while others find it less valuable.^[15-18] It is important to note that most studies have been conducted on adult patient groups, and there is limited research on the diagnostic efficiency of DSG in pediatric populations with epiphora. The goal of the present study is to evaluate the role of DSG in managing children who present with this condition.

A retrospective analysis was conducted at a tertiary care center. After thorough review, a total of 69 children with epiphora were included in the study. DSG was performed on 138 eyes–93 with epiphora symptoms and 45 without. No significant differences in age (P = 0.50) or sex distribution (P = 0.70) were observed between eyes with and without epiphora. DSG identified obstruction in 75 (80.7%) eyes exhibiting symptoms and patency in 32 (71.1%) eyes without epiphora. The overall sensitivity and specificity of DSG for detecting abnormalities in children with epiphora were 80.7% and 71.1%, respectively. Notably, over half of the patients (68%) demonstrated presac level obstruction within the study cohort.

Kim et al.^[19] conducted a study with 88 children aged 12–72 months to find out the diagnostic effectiveness of DSG in the evaluation of epiphora in children and the success rate of treatment according to scintigraphy findings. They observed that there was no significant age and sex association with clinical symptoms, which was in concordance with our observation. Like the present study, no significant association was found between clinical symptoms and demographic factors such as age or sex. Their study reported DSG sensitivity and specificity at 78.4% and 43.1%, respectively; our sensitivity was similar at 80.7%, but specificity was higher at 71.1%, likely due to nose blow and lacrimal sac massage maneuvers that reduced false positives in the present study. The surgical success rate by DSG findings was 75% in their study versus 81.3% in ours.

Sensitivity of DSG in the other studies was around 80%– 95%. ^[14,20-22] Overall success rate of surgery, depending on findings of DSG, varies from 80% to 100% in different studies.^[23,24] Sensitivity of DSG and overall surgical success rate in the present study were almost in concordance with the results of other studies.^[20,24]

In addition, we also observed that obstruction at presac level was a more common finding in our study population; 68% of children showed obstruction at presac level which was similar to the findings observed by Amanat et al.^[25] in a study with 414 patients, they found a very high incidence of presac level obstruction in their study group, and it was more common in patients with unilateral symptoms. The study also reported that 42% of asymptomatic patients exhibited obstruction on DSG. In comparison, our study group demonstrated a lower incidence of 28.9%, which may be attributed to the implementation of nose blowing and lacrimal sac massage maneuvers during image acquisition, potentially reducing the rate of false-positive results.

There are many studies in the literature that observed DSG was useful in the evaluation of patients with epiphora with high sensitivity. The success rate was high if surgery was planned according to findings of scintigraphy, and DSG is also useful in the evaluation of patency of NLD in patients after surgery.^[26]

A key observation in the present study was the occurrence of false positive obstruction patterns in fellow asymptomatic eyes (28.9%), consistent with prior reviews highlighting DSG’s specificity limitations. Conversely, DSG provided valuable guidance for surgical planning in symptomatic children, with an 81.3% success rate when management was based on DSG and clinical correlation. Interestingly, DSG may be of some help in preventing patients from unnecessary surgery if they have patent LDS on scintigraphy.^[27] In the present study, 18 of 93 eyes with epiphora (19.3%) showed patency on DSG; later were found to have conjunctivitis on slit lamp examination and were treated with medical management.

Recent review by Tawfik et al.^[27] emphasize the ongoing debate: Some authors regard DSG as highly useful, while others view it as having little added value. Our results suggest DSG remains clinically relevant in children, especially when correlated with syringing and other clinical findings, but results must be interpreted with caution.

LIMITATIONS

However, this study has some limitations, including retrospective design, an institution-based study likely to have a selection bias, and quantitative parameters like tear clearance rate at different time intervals were not derived, conducted only in a particular age group, and reliance on clinical or surgical outcomes rather than long-term functional assessment. Further research with standardized protocols, large cohort, and longer follow-up is needed.

CONCLUSION

DSG was found to be simple, easy to perform, safe, noninvasive, objective, and more physiological, with high diagnostic accuracy in the evaluation of children with epiphora, and also gives an added advantage in the planning of surgery.