A New 3D Segmentation Technique for QCT Scans of the Lumbar Spine to Determine BMD and Vertebral Geometry

TL;DR

This paper introduces a novel 3D segmentation method for QCT scans of the lumbar spine, enabling precise measurement of BMD and vertebral geometry, which may enhance fracture risk assessment.

Contribution

The study presents a new 3D segmentation technique combining deformable balloons and morphological operations, improving accuracy and reproducibility in vertebral analysis.

Findings

Segmentation precision errors < 1% for BMD

Volume measurement errors < 2%

Method shows high intra-operator consistency

Abstract

Quantitative computed tomography (QCT) is a standard method to determine bone mineral density (BMD) in the spine. Traditionally single 8 - 10 mm thick slices have been analyzed only. Current spiral CT scanners provide true 3D acquisition schemes allowing for a more differential BMD analysis and an assessment of geometric parameters, which may improve fracture prediction. We developed a novel 3D segmentation approach that combines deformable balloons, multi seeded volume growing, and dedicated morphological operations to extract the vertebral bodies. An anatomy-oriented coordinate system attached automatically to each vertebra is used to define volumes of interest. We analyzed intra-operator precision of the segmentation procedure using abdominal scans from 10 patients (60 mAs, 120 kV, slice thickness 1mm, B40s, Siemens Sensation 16). Our new segmentation method shows excellent precision errors in the order of < 1 % for BMD and < 2 % for volume.