In this paper, we present a new method which can reconstruct the three-dimensional model of nasolacrimal duct. We firstly resampled the volume data along nasolacrimal duct direction, then segmented the nasolacrimal duct into slices, and finally, completed the 3D reconstruction from the two-D contours. Using this method, we can not only reconstruct normal nasolacrimal duct, but also reconstruct catagmatic nasolacrimal duct. It overcomes the current shortcomings of some traditional methods. Consequently, the technology proposed is of great significance in computer aided technique and surgical planning related to ophthalmonogy.
Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Nasolacrimal Duct ; anatomy & histology ; diagnostic imaging ; surgery ; Reconstructive Surgical Procedures ; methods ; Tomography, X-Ray Computed

PURPOSE: To identify and analyze the role of preoperative computed tomography (CT) in patients with tearing symptoms with nasolacrimal duct obstruction (NLDO). METHODS: We retrospectively reviewed the medical records and CT results on 218 patients who complained of tearing symptoms with NLDO between January 2014 and December 2014. All patients were recruited from Kim's Eye Hospital's outpatient clinic and assessed by clinical history, examination, and CT to evaluate periocular pathology and nasolacrimal drainage system. Patients with abnormal findings assessed by preoperative CT were further reviewed. RESULTS: CT was performed on 218 patients (average age, 58.2 ± 11.9 years). Of these, 196 (89.9%) had endonasal dacryocystorhinostomy, 14 (6.4%) declined surgery, and 8 (3.7%) were inoperable due to abnormal CT findings. Soft tissue opacity was the most common finding which 243 cases (85.9%) of 283 obstructed nasolacrimal duct and 89 cases (81.7%) of 109 non-obstructed nasolacrimal duct showed it. Thirty-nine (17.8%) of 218 patients showed either maxillary sinusitis or ethmoidal sinusitis and 32 (14.7%) of 218 patients presented with periocular inflammation. Other abnormal CT findings included septal deviations, previous fractures, masses, and structural abnormalities of nasal cavity. CONCLUSIONS: Preoperative CT imaging is useful in the assessment of both nasolacrimal drainage and nearby anatomical structures. This information will be helpful in planning surgical interventions and management of NLDO.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Dacryocystorhinostomy/methods ; Female ; Follow-Up Studies ; Humans ; Lacrimal Duct Obstruction/*diagnosis ; Male ; Middle Aged ; Nasolacrimal Duct/*diagnostic imaging/surgery ; Preoperative Care/*methods ; Retrospective Studies ; Tomography, X-Ray Computed/*methods ; Young Adult