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Helical computed tomographic dacryocystography with three-dimensional reconstruction: a new view of the lacrimal
Suzanne K Freitag1, John J Woog, Philip D Kousoubris
1New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
Purpose:
To evaluate the utility of a new diagnostic radiologic technique for anatomic evaluation of the lacrimal outflow system in patients with epiphora and to delineate anatomic variations in the lacrimal systems of patients with both patent and obstructed systems.
Methods:
This study retrospectively reviewed clinical and radiologic data in a series of 30 patients with epiphora who underwent our radiologic protocol. Imaging included fluoroscopic dacryocystography followed by helical CT dacryocystography after injection of lacrimal system contrast. Axial CT data was three-dimensionally reconstructed and rotated for viewing of images in multiple projections. Mean axial cross-sectional areas of the lacrimal sac and duct were determined.
Results:
Sixty lacrimal systems in 30 patients were clinically and radiologically evaluated. The average mean cross-sectional area of the lacrimal sac and duct in the setting of complete obstruction was 0.153 cm2 and was statistically significantly larger (p=0.0286) when compared with average mean cross-sectional areas in unobstructed (0.045 cm2) and partially obstructed (0.052 cm2) lacrimal systems and were associated with lacrimal system dilation proximal to the level of obstruction. The difference in average mean cross-sectional area between patients with unobstructed and partially obstructed systems was not statistically significant. A number of lacrimal system abnormalities were noted in our series, including obstructions at various levels of the lacrimal outflow system, lacrimal sac masses, sinusitis, sarcoidosis, sinus carcinoma, and failed dacryocystorhinostomy. Twenty-three lacrimal systems were believed to be radiographically normal. Radiologic findings altered surgical treatment in 10 of 30 patients in this series.
Conclusions:
This relatively safe and well-tolerated radiologic technique provides detailed imaging of the lacrimal outflow system and surrounding structures. The information obtained from this technique may be helpful in clinical and surgical decision making.