Tehran University of Medical Sciences
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Davood Beiki

Assessment of the accuracy of lacrimal scintigraphy based on a prospective analysis of patients' symptomatology


Authors: Fard-Esfahani A, Gholamrezanezhad A, Mirpour S, Tari AS, Saghari M, Beiki D, Sichani BF, Eftekhari M,
Orbit, Vol.27, No.4, 2008,Page:237-241

BACKGROUND:

Dacryoscintigraphy is a noninvasive method frequently used for assessment of the lacrimal drainage system. Sometimes conflicting results with patients' complaints are obtained, which have no clear explanation. In our hypothesis, follow-up of patients evaluated with dacryoscintigraphy could be helpful in determining possible explanations for these conflicting results.

METHOD:

Thirty-eight consecutive patients (76 eyes) who had not previously undergone dacryocystorhinostomy or probing were entered in the study. Following instillation of 4 MBq (99m)Tc-pertechnetate, a routine procedure of dacryoscintigraphy was performed. After a mean follow-up time of 1.2 +/- 0.3 years (range 0.9-1.6 years), all patients were reassessed clinically.

RESULTS:

Using initial patients' symptoms as the gold standard, the sensitivity, specificity, NPV, and PPV of dacryoscintigraphy were calculated to be 82.1%, 75%, 60%, and 90.1%, respectively. The kappa value as a measure of agreement was 0.52. Considering the follow-up study as the gold standard, the sensitivity, specificity, NPV, and PPV were calculated as follows, respectively: 96.3%, 90.4%, 96.3%, and 90.4%. The kappa value was 0.86. There were three initially symptom-free eyes with obstructive pattern on the scans, which developed epiphora on the follow-up. In fact, these eyes were initially classified as false positive, but follow-up assessment showed that they were true-positive scans in a subclinical state.