LBD
Also written as: LBD — Largest Basal Diameter
Largest basal diameter, a critical measurement for staging and treatment planning of intraocular tumors.
Full Definition
Largest basal diameter (LBD) represents the maximum width measurement of an intraocular tumor at its base, typically obtained through standardized ultrasonography or fundus photography with measurement tools. This parameter is crucial for tumor staging systems, treatment selection, and prognostic assessment in ocular oncology. For uveal melanomas, LBD is a key component of the AJCC staging system and influences decisions between globe-preserving treatments such as plaque radiotherapy versus enucleation. Accurate measurement requires proper positioning and multiple imaging planes to ensure the true maximum diameter is captured. LBD measurements are typically reported in millimeters and should be documented consistently across follow-up examinations.
Usage
Usage note: Always specify units (mm) and measurement method when documenting LBD.
In Context
- "The uveal melanoma measured 12.3 mm LBD with an apical height of 4.2 mm on A-scan ultrasonography." — Imaging report
- "Tumors with LBD exceeding 15 mm are generally considered unsuitable for plaque radiotherapy." — Treatment planning guidelines