Purpose:
The maximum intensity projection (MIP) allows the visualization of the highest or lowest intensity in a data volume along the current line of sight. The purpose of this study is to present the 3D MIP image of the optic nerve head (ONH) derived from spectral domain optical coherence tomography (SD-OCT) images, and to compare the reproducibility of measuring lamina cribrosa thickness (LCT) using MIP and standard B-scan images.
Methods:
Optic discs of 20 healthy subjects, 20 glaucoma suspects and 30 glaucoma patients were scanned using enhanced depth imaging SD-OCT. The B-scan images were reconstructed 3 dimensionally using MIP. The LCT was measured in the thin volumetric section images generated by MIP as well as in the corresponding B-scan images. The LCT was defined as the distance between the level of anterior and the posterior borders of the lamina cribrosa.
Results:
The mean mid-horizontal LCT was 231.43 ± 41.38 μm in MIP volume images and 233.25 ± 43.18 μm in B-scan images. In general, the borders of the lamina cribrosa were more clearly visible using MIP images. The intraobserver and interobserver ICC were 0.940 and 0.875 for MIP images and 0.858 and 0.831 for B-scan images, respectively.
Conclusions:
Thin volume section images generated by MIP had higher reproducibility in measuring LCT than the standard B-scan images. Using those images, the detection of the LC borders was more straightforward. This technique should facilitate the research involving the measurement of LCT.
Keywords: lamina cribrosa • image processing