Three-dimensional Bone Mineral Density Research Articles

Usefulness of volumetric BMD measurement by using low dose CT image acquired on L-spine Bone SPECT/CT

Purpose: CT scan makes up for the weak point of the nuclear medicine image having a low resolution and also were used for attenuation correction on image reconstruction. Recently, many studies try to make use of CT images additionally, one of them is to measure the bone mineral density(BMD) using Quantitative CT(QCT) software. BMD exams are performed to scan lumbar and femur with DXA(Dual-Energy X-Ray Absorptiometry) in order to diagnose bone disease such as osteopenia, osteoporosis. The purpose of this study is to identify the usefulness of QCT_BMD analyzed with low dose CT images on L-spine Bone SPECT/CT comparing with DXA_BMD. Materials and Methods: Fifty five women over 50 years old (mean 66.4 ± 9.1) who took the both examinations(L-spine Bone SPECT/CT with SIEMENS Intevo 16 and DXA scan with GE Lunar prodigy advance) within 90 days from April 2017 to July 2022, BMD, T-score and disease classification were analyzed. Three-dimensional BMD was analyzed with low dose CT images acquired on L-spine Bone SPECT/CT scan on Mindways QCT PROTM software and two-dimensional BMD was analyzed on DXA scan. Basically, Lumbar 1-4 were analyzed and the patients who has lesion or spine implants on L-spine were excluded for this study. Pearson's correlation analysis was performed in BMD and T-score, chi-square test was performed in disease classification between QCT and DXA. Results: On 55 patients, the minimum of QCT_BMD was 18.10, maximum was 166.50, average was 82.71 ± 31.5 mg/cm3. And the minimum of DXA-BMD was 0.540, maximum was 1.302, average was 0.902 ± 0.201 g/cm2, respectively. The result shows a strong statistical correlation between QCT_BMD and DXA_BMD(p<0.001, r=0.76). The minimum of QCT_T-score was -5.7, maximum was-0.1, average was -3.2 ± 1.3 and the minimum of DXA_T-score was -5.0, maximum was 1.7, average was -2.0 ± 1.3, respectively. The result shows a statistical correlation between QCT T-score and DXA T-score (p<0.001, r=0.66). On the disease classification, normal was 5, osteopenia was 25, osteoporosis was 25 in QCT and normal was 10, osteopenia was 25, osteoporosis was 20 in DXA. There was under-estimation of bone decrease relatively on DXA than QCT, but there was no significant differences statistically by chi-square test between QCT and DXA. Conclusion: Through this study, we could identify that the QCT measurement with low dose CT images QCT from L-Spine Bone SPECT/CT was reliable because of a strong statistical correlation between QCT_BMD and DXA_BMD. Bone SPECT/CT scan can provide three-dimensional information also BMD measurement with CT images. In the future, rather than various exams such as CT, BMD, Bone scan are performed, it will be possible to provide multipurpose information via only SPECT/CT scan. In addition, it will be very helpful clinically in the sense that we can provide a diagnosis of potential osteoporosis, especially in middleaged patients.

Development of a system to assess the two- and three-dimensional bone mineral density of the lumbar vertebrae from clinical quantitative CT images.

To date, the assessment of bone mineral density (BMD) using CT images has been made in three dimensions, leading to errors in detecting osteoporosis based on the two-dimensional assessments of BMD using dual-energy X-ray absorptiometry (DXA-BMD). Herein, we aimed to develop a system that measures two- and three-dimensional lumbar BMD from quantitative CT images and validated the accuracy of the system in diagnosing osteoporosis with regard to the DXA classification. Fifty-nine pairs of spinal CT and DXA images were analyzed. First, the three-dimensional BMD was measured at the axial slice of the L1 vertebra on CT images (L1-vBMD). Then, the L1-L4 vertebrae were segmented from the CT images to measure the three-dimensional BMD at the trabecular region of the L1-L4 vertebral bodies (CT-vBMD). Lastly, the segmented vertebrae were projected onto the coronal plane to measure the two-dimensional BMD (CT-aBMD). Each parameter was correlated with DXA-BMD, and the receiver operating characteristic (ROC) curve to diagnose osteoporosis was assessed. The correlation coefficients of DXA-BMD with L1-vBMD, CT-vBMD, and CT-aBMD were 0.364, 0.456, and 0.911, respectively (all p < 0.01). In the ROC curve analysis to diagnose osteoporosis, the area under the curve for CT-aBMD (0.941) was significantly higher than those for L1-vBMD (0.582) and CT-vBMD (0.657) (both p < 0.01). Compared with L1-vBMD and CT-vBMD, CT-aBMD could accurately predict DXA-BMD and detect patients with osteoporosis. Given that our method can quantify BMD in both two and three dimensions, it could be used to screen for osteoporosis from quantitative CT images.

Three-Dimensional Quantification of Bone Mineral Density in the Distal Femur and Proximal Tibia Based on Computed Tomography: In Vitro Evaluation of an Extended Standardization Method.

While alterations in bone mineral density (BMD) are of interest in a number of musculoskeletal conditions affecting the knee, their analysis is limited by a lack of tools able to take full advantage of modern imaging modalities. This study introduced a new method, combining computed tomography (CT) and computational anatomy algorithms, to produce standardized three-dimensional BMD quantification in the distal femur and proximal tibia. The method was evaluated on ten cadaveric knees CT-scanned twice and processed following three different experimental settings to assess the influence of different scans and operators. The median reliability (intraclass correlation coefficient (ICC)) ranged from 0.96 to 0.99 and the median reproducibility (precision error (RMSSD)) ranged from 3.97 to 10.75 mg/cc for the different experimental settings. In conclusion, this paper presented a method to standardize three-dimensional knee BMD with excellent reliability and adequate reproducibility to be used in research and clinical applications. The perspectives offered by this novel method are further reinforced by the fact it relies on conventional CT scan of the knee. The standardization method introduced in this work is not limited to BMD and could be adapted to quantify other bone parameters in three dimension based on CT images or images acquired using different modalities.

Evaluation Methods of Bone Graft Materials

Bone graft substitute materials play an important role in oral rehabilitation and understanding the biological effects of these materials is important for an optimum use. Many bone graft substitutes have been approved for clinical use but this large variability make it hard to select a graft materials. The present study aimed to evaluate the methods that we can today use to assess the degree of osseointegration of the synthetic bone augmentation materials.For this study we made three study groups, each of them consisting of six laboratory rats. On the maxilla of this animals 3-mm diameter experimental cavities were carried out. For the first study group the cavities were augmented with the collagen fleece Alveoprotect, for the second group with the synthetic bone graft Ossceram nano, and in the third group the experimental cavities were left unaugmented. The obtained samples were subjected to three examination methods: clinical and radiological examination, Optical Coherence Tomography (OCT), and a histological study.The evaluation methods of bone graft materials may be divided in two categories: in vivo and in vitro methods. In vivo methods include clinical evaluation and imagistic such as radiological or computer tomography (CT) evaluation. Even a minimal but careful direct clinical observation allows observing the appearance of the bone defect healing at its different stages. CBCT scan is the imaging method of choice in the graft materials repairment of the osseous defects because provides 3D volumetric measurements of newly formed hard tissues.Optical Coherence Tomography (OCT) is a constantly growing imaging method characterized by high spatial resolution and noninvasive subsurface detection. The OCT allowed us to evaluate the surface and subsurface of the ongoing healing bone defects in a non-destructive manner.For the in vitro methods histological methods represents the classical evaluation of the bone graft materials biological integration. On the histological samples we generally noticed the experimental defects filling with connective tissuewith various bone ingrowths from the surrounding bone tissue.However new emerging methods give new opportunities to a more accurate research of this materials. The microcomputed tomography analysis may determine the relationships and differences in three-dimensional bone mineral density and microtrabecular structures between bone grafts and their adjacent native boneTo design and produce an efficient bone graft, the researchers and clinicians should have sufficient knowledge of the characteristics of grafts such as osteogenesis, osteoinductivity, and osteoconductivity, and their other advantages and disadvantages.

Assessment of effect of anti-osteoporotic agents using high-resolution CT

Quantitative computed tomography (QCT) provides three-dimensional bone mineral density (BMD) of trabecular and cortical components separately, as well as macroscopic bone configuration. High resolution CT (HRCT) measures bone geometry more precisely than conventional CT, which enables to assess the effects of anti-osteoporotic agents. HRCT is also able to analyze in vivo trabecular microstructure. CT has an advantage to demonstrate the trabecular microstructure in axial skeleton such as vertebra or hip, which can be expected to contribute to evaluate the effects of anti-osteoporotic agents.

Bone mineral density in patients with growth hormone deficiency: does a gender difference exist?

The aim of the study was to clarify whether a gender difference exists with respect to bone mineral density (BMD) and bone mineral content (BMC) in adult patients with growth hormone deficiency (GHD). A case-control design. Blood sampling for measurements of calcium, phosphate, creatinine, PTH, vitamin D, IGF-1, markers of bone formation and bone resorption, and dual energy X-ray absorptiometry (DEXA), to determine BMD and BMC of the lumbar spine, hip, distal arm and total body, were performed in 34 patients with GHD (19 females) and 34 sex-, age- and weight-matched healthy control subjects. The patients were well substituted on all pituitary axes, apart from GH. GH-deficient males had significantly lower BMD in the lumbar spine (P = 0.02), hip (P = 0.01) and total body (P = 0.003) than healthy males while GH-deficient females compared to healthy females had identical BMD values at all regions. This gender difference was even more obvious when BMD values were expressed as Z-scores or as three-dimensional BMD of the total body. The bone formation and bone resorption markers, as well as calcium and vitamin D, were all at the same levels in GH-deficient and healthy males, indicating identical bone turnover. The GH-deficient females, however, had significantly lower levels of bone markers compared to healthy females, indicating a reduced bone turnover. Oestrogen substitution of the GH-deficient females could explain this difference. Compared to healthy control subjects GH-deficient males had, in contrast to GH-deficient females, significantly reduced BMD and BMC. This obvious gender difference seems to be caused by the oestrogen substitution given to the females, compensating for the lack of GH, an effect testosterone does not seem to possess.

Separate measurement of radial trabecular and cortical bone mineral density by peripheral quantitative computed tomography (pQCT) in degenerative joint disease

Degenerative joint disease and osteoporosis, both of which tend to increase with advance in age, were thought to be essentially different mainly because of the artifactually high lumbar spine bone mineral density (BMD) in the former unlike osteoporosis characterized by persistent decrease of BMD. To clarify the relationship between these two diseases, three-dimensional BMD of the trabecular and cortical bone was measured separately in an area of the radius relatively free of degenerative changes by peripheral computed tomography (pQCT). In addition to radiological assessment of spondylosis deformans, quantification of vertebral deformity was attempted by calculation of standard deviation, coefficient of variation, difference between maximum and minimum density divided by the mean of L1-L4. With advance in age and progress of spondylosis deformans, the standard deviation, coefficient of variation difference between the maximum and minimum density and this difference divided by the mean of L1-L4 increased, but radial trabecular bone density, cortcal density and relative cortical volume decreased, suggesting parallel advance of degenerative joint disease and osteoporosis. Sodium etidronate, an antiresorber commonly used in the treatment of osteoporosis, increased mean lumbar spine BMD and markedly decreased the standard deviation, coefficient of variation, difference between the maximum and minimum density and this difference divided by the mean of L1 and L2 but maintained maximum BMD constant, decreasing vertebral deformity due to spondylosis deformans. It is conceivable that calcium release from bone on increased resorption leads to osteoporosis, and calcium entrance into cartilage, causing its hardening, disappearance and degeneration, direct contact between bones, osteoarthritis and subsequent deformity in a single sequence of events.