Palaniswamy Shanmuga Sundaram, Subramanyam Padma
Department of Nuclear Medicine & PET CT, Amrita Institute of Medical Sciences, Cochin, Kerala, India.
Nucl Med Commun. 2012 Mar;33(3):262-7. doi: 10.1097/MNM.0b013e32834f6cf7.
Dacryoscintigraphy is a grossly underutilized nuclear medicine procedure for assessing the patency of nasolacrimal ducts. It is an alternate noninvasive modality requiring no added expertise when compared with dacryocystography, an invasive radiological counterpart. Dacryocystorhinostomy (DCR) is a surgical procedure in which a patent rhinostomy is made so that a low-pressure lacrimal bypass system is created, thus relieving epiphora, dacryocystitis or mucocele. DCR has been accepted as a highly successful procedure in the management of epiphora from nasolacrimal duct obstruction; however, adverse local effects can reproduce epiphora. This study highlights the utility and simplicity of dacryoscintigraphy in the postoperative setting of DCR, apart from showcasing its high sensitivity and accuracy in localizing the sites of lacrimal drainage obstruction.
Fifty-five postoperative patients of DCR were screened. Ten volunteers constituted the control group. One drop (10 μl) of technetium pertechnetate (TcO4) was instilled simultaneously in the outer canthus of both eyes (50-100 μCi). Upright dynamic (8 min) and anterior static images of the eyes (up to 20 min) were acquired on a gamma camera fitted with a high-resolution collimator. Physiological interventions that were used in this study were eye blinking, saline intervention, and lacrimal sac massaging.
Out of 40 symptomatic DCR patients, 22 had complete obstruction at the presac level and 18 patients had partial obstruction. Quantitative parameters like tear transit time and lacrimal sac half-life were also calculated. After massage of the lacrimal sac, progression of the tracer was observed in five patients. Premassage and postmassage tear column measurements showed a relative increase of 30.1%. Massage of eight clinically normal ducts showed a relative increase of 2.4% (P=0.06). Statistical analysis using the Fisher test shows very significant concordance between clinical symptoms and dacryoscintigraphy findings in postoperative DCR patients (P<0.0001). The modified McNemar's pair test did not show statistically significant differences between dacryoscintigraphy and the syringing irrigation test.
Dacryoscintigraphy is a simple and easy-to-perform investigation providing high sensitivity in epiphora detection in patients after DCR. Interventions play a role in further enhancing the sensitivity of the technique. This study demonstrates the utility of dacryoscintigraphy in detecting subclinical and partial lacrimal duct obstruction with good patient compliance. It provides an easy and effective way of screening families, enabling an early diagnosis. During imaging, a high-resolution collimator is found to be an efficient substitute for the conventional pinhole collimator.
泪道闪烁造影是一种在评估鼻泪管通畅性方面严重未得到充分利用的核医学检查方法。与泪囊造影（一种侵入性放射学检查方法）相比，它是一种无需额外专业技能的替代性非侵入性检查方法。泪囊鼻腔吻合术（DCR）是一种外科手术，通过建立一个通畅的鼻造口来创建一个低压泪液旁路系统，从而缓解溢泪、泪囊炎或黏液囊肿。DCR已被公认为是治疗鼻泪管阻塞引起的溢泪的一种非常成功的手术；然而，局部不良反应可能会再次导致溢泪。本研究强调了泪道闪烁造影在DCR术后的实用性和简便性，同时展示了其在定位泪液引流阻塞部位方面的高敏感性和准确性。
对55例DCR术后患者进行筛选。10名志愿者组成对照组。将一滴（10 μl）高锝酸盐（TcO4）同时滴入双眼外眦（50 - 100 μCi）。使用配备高分辨率准直器的γ相机采集双眼的直立动态图像（8分钟）和前部静态图像（最长20分钟）。本研究中使用的生理干预措施包括眨眼、盐水干预和泪囊按摩。
在40例有症状的DCR患者中，22例在泪囊前水平完全阻塞，18例部分阻塞。还计算了泪液通过时间和泪囊半衰期等定量参数。泪囊按摩后，观察到5例患者示踪剂向前推进。按摩前和按摩后泪柱测量显示相对增加了30.1%。对8条临床正常泪道进行按摩显示相对增加了2.4%（P = 0.06）。使用Fisher检验的统计分析显示，术后DCR患者的临床症状与泪道闪烁造影结果之间具有非常显著的一致性（P < 0.0001）。改良的McNemar配对检验显示泪道闪烁造影与冲洗试验之间无统计学显著差异。
泪道闪烁造影是一种简单易行的检查方法，对DCR术后患者溢泪检测具有高敏感性。干预措施在进一步提高该技术的敏感性方面发挥作用。本研究证明了泪道闪烁造影在检测亚临床和部分泪道阻塞方面的实用性，患者依从性良好。它提供了一种简单有效的家庭筛查方法，能够实现早期诊断。在成像过程中，发现高分辨率准直器是传统针孔准直器的有效替代品。
