Comparison of the Hounsfield Unit in CT scan with the Gray Level in cone-beam CT

Razi, Tahmineh; Emamverdizadeh, Parya; Nilavar, Nadia; Razi, Sedigheh

doi:10.15171/joddd.2019.028

Cited by 50 publications

(53 citation statements)

References 21 publications

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“…stated that gray scale in CBCT is the standard for measuring bone density before implant treatment, and that this method is recommended because of the lower radiation dose and cost compared to CT scanning. 25 However, Cassetta reported that a conversion ratio must be applied to the VV to more accurately define the bone density with CBCT. 26 …”

Section: Discussionmentioning

confidence: 99%

Cone beam computed tomography analysis of the edentulous mandibular symphysis

Mense

Saliba-Serre

Ferrandez

et al. 2021

Journal of Dental Sciences

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Background/purpose Overdenture with single symphyseal implant is one of the useful clinical approach for elderly edentulous patients. We aimed to evaluate edentulous patients with regards to the relationship between dimensions, bone characteristics, cancellous densities, and cortical thickness of the mandibular symphyseal region using cone beam computed tomography (CBCT). Material and methods We analyzed 103 CBCT from pre-implant investigations. All included patients were healthy without any disorders affecting bone metabolism. We performed 13 measurements for each patient: 9 of height, width, and thickness (mm) and 4 of density (Hounsfield Units; HU). Fisher's exact test was applied to examine the association between two categorical variables, the Pearson correlation coefficient to measure the strength of linear relationship between two quantitative variables. We used the two-sample Student's t-test to compare mean symphysis height between men and women, the paired Student's t-test to compare mean lingual and buccal cortical thickness. For all tests, the threshold of significance was fixed at 5%. Results Men and women significantly differed with regards to mean total symphysis height ( p = 0.004) and the distribution of Cawood and Howell classifications ( p = 0.033). Symphysis height was negatively correlated with mean density of cancellous bone (r = −0.453, p < 0.001). Mean lingual cortical thickness significantly differed from mean vestibular thickness ( p < 0.001, paired Student's t-test). Conclusion Present findings supported that symphyseal measurements are parameters that reflect the symphysis bone characteristics, and can guide the choice of a suitable implant design.

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Section: Discussionmentioning

confidence: 99%

Cone beam computed tomography analysis of the edentulous mandibular symphysis

Mense

Saliba-Serre

Ferrandez

et al. 2021

Journal of Dental Sciences

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“…They suggested that CBCT scans are suitable to predict the implant stability and, therefore, help decide whether immediate or early loading of implants should be performed [ 22 ]. CT scans do not appear to have any advantage over CBCT scans in classifying bone quality [ 32 ]. The mean gray values obtained by a CBCT scan and HUs in a CT scan show a strong correlation [ 33 ].…”

Section: Discussionmentioning

confidence: 99%

“…CT scans do not appear to have any advantage over CBCT scans in classifying bone quality [32]. The mean gray values obtained by a CBCT scan and HUs in a CT scan show a strong correlation [33].…”

Section: Measurements Of Bone Densitymentioning

confidence: 99%

Associations among Primary Stability, Histomorphometric Findings, and Bone Density: A Prospective Randomized Study after Alveolar Ridge Preservation with a Collagen Cone

et al. 2020

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Background: The objective of this investigation was to examine whether determination of bone density (BD) with a cone beam computed tomography (CBCT) scan could help predict the primary stability (PS) of the implants and to investigate whether associations between the histomorphometric findings and the CBCT scan could be observed. Materials and methods: In this randomized clinical study, the efficacy of alveolar ridge preservation (ARP) with a combination of a collagen cone and a collagen membrane procedure after tooth extraction was investigated. CBCT scans were obtained after a healing period of 8 (±1) weeks. Subsequently, the CBCT scans were evaluated in terms of BD at different heights of the former socket. Eleven (±1) weeks after tooth extraction, implant placement was performed and PS was measured with resonance frequency analysis. Potential associations among the radiologically measured BD, the histomorphometric results, and the PS were analyzed. Results: No direct association was observed between the radiologically determined BD and the histomorphometric findings. No significant associations could be found between the BD and the PS. Conclusion: No significant associations were observed among the BD determined by the CBCT, the histomorphometric findings, and the PS.

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“…When these algorithms will be applied for a cone-beam CT (CBCT), we must convert a gray scale value to a Hounsfield unit value. Some studies have shown a strong linear relationship between Hounsfield units (HU) and gray scale [19,20]. Gray scale is different from HU due to higher noise levels, more scattered radiation, high heel effect, and beam hardening artifacts [21,22].…”

Section: The Problem Of Threshold Value Adapted To Any Ct or A Cone-beam Ctmentioning

confidence: 99%

The Membranous Labyrinth in vivo from High-Resolution Temporal Bone CT Data

Tanioka¹,

Tanioka²

2021

J Head Neck Surg

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Purpose: A prerequisite for the modeling and understanding of the inner ear mechanics needs the accurate created membranous labyrinth. We will present a semi-automated methodology for accurate reconstruction of the membranous labyrinth in the cochlea from high-resolution temporal bone CT data. Method:We created the new imaging technique which was combined with the segmentation methodology, transparent, Thresholding, and opacity curve algorithms. This technique allowed the simultaneous multiple images creating without any overlapping regions in the inner ear has been developed from temporal bone CT data. Results:The reconstructed 3D images improved the in vivo cochlear membranous labyrinth geometry to realistically represented physiologic dimensions. These generated membranous structures were in good agreement with the previously published ones, while this approach was the most realistic in terms of the membranous labyrinth in the cochlea. Conclusions:The precise volume rendering depends on proprietary algorithms so that different results can be obtained, and the images appear qualitatively different. For each anatomical question, a different visualization technique should be used to obtain an optimal result. All researchers can create the in vivo 3D membranous labyrinth in the cochlea in real-time like a retinal camera. This technique will be applied to a cone-beam CT dataset.

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Comparison of the Hounsfield Unit in CT scan with the Gray Level in cone-beam CT

Cited by 50 publications

References 21 publications

Cone beam computed tomography analysis of the edentulous mandibular symphysis

Cone beam computed tomography analysis of the edentulous mandibular symphysis

Associations among Primary Stability, Histomorphometric Findings, and Bone Density: A Prospective Randomized Study after Alveolar Ridge Preservation with a Collagen Cone

The Membranous Labyrinth in vivo from High-Resolution Temporal Bone CT Data

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