an analogy between gray values of cone beam computed tomography and hounsfield units of ct: a systematic review and meta-analysis

Background: this study was conducted to determine and compare the efficacy of hounsfield units (hu) of computed tomography (ct) and gray values (gv) of cone beam computed tomography (cbct) in assessing bone mineral density.methods: literature search was carried out using electronic databases including pubmed, google scholar, scopus. in vivo, in vitro and animal studies that analyzed the comparison between the gv of cbct and hu of ct were included. this review adheres to the prisma guidelines, and quadas-2 tool for risk of bias assessment was performed.results: a total of 4760 studies were roped in for this systematic review, of which 22 articles were included and 8 articles were selected for the meta-analysis. the odds ratio of 8 included articles showed a strong positive correlation between ct and cbct and the overall classification of 89.86% was obtained. 19 studies had low risk of bias and 4 studies had high risk. some of the included studies indicated quite low and limited reliability, advocating the need for clinical studies with diagnostic capacity to support the use.conclusion: the existing evidence suggests that gvs of cbct and hus of ct had a strong positive correlation and the standard formula for the conversion between the two parameters (gray values and hounsfield units) need to be derived in future studies with clinical correlation.