Fractal dimension analysis on CBCT scans for detecting low bone mineral density in postmenopausal women

Abstract

Purpose The aim of this study was to compare the fractal dimension (FD) measured at 2 bone sites (second cervical vertebra and mandible) on cone-beam computed tomography (CBCT). The research question was whether FD could serve as an accessory tool to refer postmenopausal women for densitometric analysis. Therefore, the reliability and accuracy of FD were evaluated. Materials and Methods In total, 103 postmenopausal women were evaluated, of whom 52 had normal bone mineral density and 51 had osteoporosis, according to dual X-ray absorptiometry of the lumbar spine and hip. On the CBCT scans, 2 regions of interest were selected for FD analysis: 1 at the second cervical vertebra and 1 located at the mandible. The correlations between both measurements, intra- and inter-observer agreement, and the accuracy of the measurements were calculated. A P value less than 0.05 was considered to indicate statistical significance for all tests. Results The mean FD values were significantly lower at the mandibular region of interest in osteoporotic patients than in individuals with normal bone mineral density. The areas under the curve were 0.644 ( P =0.008) and 0.531 ( P =0.720) for the mandibular and vertebral sites, respectively. Conclusion FD at the vertebral site could not be used as an adjuvant tool to refer women for osteoporosis investigation. Although FD differed between women with normal BMD and osteoporosis at the mandibular site, it demonstrated low accuracy and reliability.

Utility of Cone-Beam Computed Tomography in the Detection of Low Bone Mass—A Systematic Review

“…Mathematical analysis of the fractal dimension (FD) was found in three of the included studies, one of which also included the largest number of patients [ 1 ]. The same study showed a significant difference between normal BMD and osteoporosis via mandibular FD analysis, but with low accuracy and reliability (AUC = 0.644, p = 0.008).…”

“…At the same time, using fractal dimension (FD) measurements to differentiate between low and normal bone mass showed a statistically significant correlation with the mandibular trabecular bone, but not with the vertebrae in a study published in 2022 [ 1 ], but with low accuracy (area under the curve of 0.64). At the same time, a meta-analysis regarding the use of fractal analysis in dental radiology for osteoporosis detection stated that FD could not be used to identify osteoporotic patients [ 33 ].…”

“…Cone-beam computed tomography (CBCT) is frequently used in the preoperative qualitative and quantitative assessment of implant sites. It is preferred due to its relatively low cost and reduced radiation dose [ 1 , 2 ]. Low bone mass, diagnosed as osteopenia or osteoporosis (OP), is evaluated using dual-energy X-ray absorptiometry (DXA scan) and quantitative CT scan (QCT) [ 3 ].…”