UNASSIGNED: Prospective cohort study.
UNASSIGNED: This study aimed to identify the optimal preoperative bone health assessment for adult spinal deformity (ASD) surgery through correlation analysis between intraoperative pedicle screw (PS) insertion torque and various bone quality measures, including bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DEXA), Hounsfield unit (HU) by computed tomography (CT), and vertebral bone quality (VBQ) score by magnetic resonance imaging.
UNASSIGNED: Existing data on optimal assessment tools for ASD surgery are limited.
UNASSIGNED: The study included patients with ASD aged >60 years who underwent spinal corrective fusion surgery from the lower thoracic spine to the pelvis. The intraoperative PS insertion torque was measured using a torque meter. Pearson correlation coefficients were calculated between the PS insertion torque and the BMD, HU, and VBQ score. Preoperative bone quality was compared between the proximal junctional failure (PJF) and non-PJF groups.
UNASSIGNED: Thirty-one patients with 177 PS at T10, T11, and T12 were analyzed. The PS insertion torque showed a moderate positive correlation with lumbar spine BMD (r=0.59-0.69, p<0.01), total hip BMD (0.58-0.62, p<0.01), and HU value (r=0.58-0.66, p<0.01). However, the VBQ score did not show significant correlation (r=-0.28 to -0.23, p >0.05). Notably, a strong correlation was found between the PS insertion torque and the HU value for screws of the same size (r=0.71 and 0.74, p<0.01). The HU value at T12 and the PS insertion torque at T10 were significantly lower in the PJF group than in the non-PJF group.
UNASSIGNED: This study demonstrates a positive correlation between the PS insertion torque and HU value in the lower thoracic spine and a moderate correlation with BMD but not the VBQ score. Preoperative assessment using DEXA and CT is crucial for optimizing bone health management in ASD surgery.

BACKGROUND: In rhinoplasty, calcification around silicone implants is frequently observed in the tip dorsum (TD) area. Additionally, based on a review of various literature, it is presumed that calcification in silicone implants occurs due to both inflammatory chemical reactions and physical friction against the tissue. The calcification of nasal silicone implants not only results in the functional loss of the implants, but also leads to material deformation. However, there is a lack of research on calcification of nasal silicone implants in the current literature.
OBJECTIVE: To elucidate various clinical characteristics of calcification around nasal silicone implants, using histological and radiological analysis.
METHODS: This study analyzed data from 16 patients of calcified nasal implants, who underwent revision rhinoplasty for various reasons after undergoing augmentation rhinoplasty with silicone implants. The collected data included information on implant duration, implant types, location of calcification, presence of inflammatory reactions, and computed tomography (CT) scans.
RESULTS: The most common location of calcification, as visually analyzed, was in the TD area, accounting for 56%. Additionally, the analysis of CT scans revealed a trend of increasing Hounsfield Unit values for calcification with the duration of implantation, although this trend was not statistically significant (P = 0.139).
CONCLUSIONS: Our study shows that reducing the frequency of calcification may be achievable by using softer silicone implants and by minimizing the damage to perioperative tissues.

Pedicle screw loosening after posterior lumbar fusion is associated with poor bone quality, which often determines screw pull-out strength, insertion torque, and vertebral body loading characteristics. Magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score were associated with poor bone quality. Current evidence suggests that pedicle bone quality (PBQ) has a greater impact on screw stability. However, the correlation between MRI-based PBQ score and screw loosening has not been reported.
OBJECTIVE: To introduce and evaluate an MRI-based PBQ score to determine its effectiveness in predicting pedicle screw loosening following lumbar fusion surgery.
METHODS: The retrospective study analyzed 244 patients who underwent posterior lumbar interbody fusion (PLIF) with pedicle screws between December 2017 and December 2021, with CT and MRI imaging before surgery. Data collected included patient demographics and preoperative radiological data. Radiographic screw loosening was measured at 12 months postoperatively. Clinical assessments included pain visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The PBQ score was measured using MRI scans. We use univariate analysis for preliminary screening of the risk factors of screw loosening. Subsequent analysis involved multivariate logistic regression to identify independent predictive factors for screw loosening. We constructed the receiver operating characteristic (ROC) curve to ascertain the discriminative capacity of the PBQ score. The area under the curve (AUC) quantified its predictive accuracy. Additionally, we evaluated the association between PBQ score and screw loosening using Spearman\'s correlation analysis.
RESULTS: Overall, 244 patients who underwent PLIF with pedicle screw fixation participated in this study, including 35 in the loosening group and 209 in the non-loosening group. PBQ score in the loosening group was significantly higher than that in the non-loosening group. On multivariate logistic regression, the higher PBQ score (OR = 8.481, 95% CI: 3.158-22.774; p < 0.001) and the lower mean Hounsfield unit (HU) value of L1-4 (OR = 0.967, 95% CI 0.951-0.984; p < 0.001) were the variables that significantly predicted screw loosening. The AUC for the PBQ score and HU value were 0.751 (95% CI: 0.673-0.828) and 0.702 (95% CI: 0.612-0.791). The PBQ score optimal cutoff to differentiate patients with loosening and with non-loosening was calculated as 3.045 with a sensitivity of 85.7% and specificity of 76.9%, while the optimal cutoff of the HU value was 151.5 with a sensitivity of 64.6% and specificity of 89.5%.
CONCLUSIONS: The association between the PBQ score and the propensity for lumbar pedicle screw loosening was found to be substantial. As a predictive measure, the PBQ score outperformed the HU value in forecasting the likelihood of screw loosening post-posterior lumbar fusion.

OBJECTIVE: The Hounsfield unit density value (HUDV) is a relative quantitative measurement of radio density used by radiologists in the interpretation of computed tomography (CT) images. Our aim is to investigate the role of HUDV in evaluating pre-epiglottic space (PES) involvement of laryngeal carcinoma.
METHODS: Seventy-four patients treated for laryngeal carcinoma in our clinic between 2014 and 2019 were included in the study. The invasion status of PES was determined radiologically and pathologically. HUDV was measured with a circular selected region of interest, with a constant size of 10 mm2 for PES. The relationship between patological PES invasion, radiological PES invasion, and HUDV was evaluated.
RESULTS: Measuring HUDV to determine PES invasion (74.3 %) was significantly higher than​​ conventional CT evaluation (59.5 %) (p = 0.001). The agreement coefficient (kappa value) of the conventional CT evaluation and the HUDV regarding PES involvement was 0.673, which was interpreted as \'good\'.
CONCLUSIONS: HUDV could be used as an additional tool in diagnosing pre-epiglottic space invasion in laryngeal cancer.

UNASSIGNED: Retrospective radiological analysis.
UNASSIGNED: The aim of this study is to evaluate the distribution of bone mineral density (BMD) in lumbar vertebrae using the Hounsfield unit (HU) measurement method and investigate the clinical implications of HU values for assessing lumbar vertebrae BMD.
UNASSIGNED: Two hundred and ninety-six patients were retrospectively reviewed and divided into six groups according to age: Group 1(20-29 years old), Group 2 (30-39 years old), Group 3 (40-49 years old), Group 4 (50-59 years old), Group 5 (60-69 years old), Group 6 (70-79 years old). Six different locations from each vertebra of L1-L5 were selected as regions of interest: the anterior, middle and posterior parts of the upper and lower slices of the vertebrae. HU values were measured for the six regions of interest, followed by statistical analysis.
UNASSIGNED: The HU values of vertebrae showed a decreasing trend from young patients to elderly patients in Group 1 to Group 5. There was no significant difference in HU values among different vertebrae in the same age group. In all age groups, the HU values of the anterior and posterior part of the vertebral body were significantly different from L1 to L3, with the anterior part of the vertebral body having lower HU values than the posterior part. The HU values of the anterior and posterior part of the vertebral body of L4 and L5 were statistically significant only in Group 5 and Group 6, and the HU values of the anterior part of the vertebral body were lower than those of the posterior part. The HU values of posterior part of L4 and L5 in Group6 were higher than those in Group5.
UNASSIGNED: Bone mineral density in the lumbar vertebrae is not uniformly distributed, potentially attributed to varying stress stimuli. The assessment of local HU values in the lumbar spine is of significant importance for surgical treatment.

Proximal junctional kyphosis and failure is a common complication of adult spinal deformity surgery, with osteoporosis as a risk factor. This retrospective study investigated the influence of long thoracolumbar fusion with pelvic fixation on regional bone density of adjacent vertebrae (Hounsfield units on computed tomography) and evaluated the association between bone loss and the incidence of proximal junctional kyphosis and failure. Patients who underwent long thoracolumbar fusion (pelvis to T10 or above) or single-level posterior lumbar interbody fusion (control group) between 2016 and 2022 were recruited. Routine computed tomography preoperatively and within 1-2 weeks postoperatively was performed. Postoperative changes in Hounsfield unit values in the vertebrae at one and two levels above the uppermost instrumented vertebrae (UIV + 1 and UIV + 2) were evaluated. Overall, 127 patients were recruited: 45 long fusion (age, 73.9 ± 5.6 years) and 82 proximal junctional kyphosis and failure (age, 72.5 ± 9.3 years). Postoperative computed tomography was performed at a median [interquartile range] of 3.0 [1.0-7.0] and 4.0 [1.0-7.0] days, respectively. In both groups, Hounsfield unit values at UIV + 2 were significantly decreased postoperatively. In the long-fusion group, Hounsfield unit values at UIV + 1 and UIV + 2 were significantly lower in patients with proximal junctional kyphosis and failure (within 18 months postoperatively) than in those without proximal junctional kyphosis and failure. Proximal junctional kyphosis and failure and long thoraco-pelvic fusion negatively affect regional Hounsfield unit values at adjacent levels immediately after surgery. Patients with subsequent proximal junctional kyphosis and failure show greater postoperative bone loss at adjacent levels than those without.

METHODS: Retrospective study.
OBJECTIVE: To compare and correlate technetium-99m methylene diphosphonate uptake between benign and metastatic bone lesions using semiquantitative analysis of maximum standard uptake value (SUVmax) and mean Hounsfield unit (HU) in single-photon emission computed tomography-computed tomography (SPECT-CT).
BACKGROUND: Qualitative interpretation of metastatic bone lesions in breast cancer on bone scintigraphy is often complicated by coexisting benign lesions.
METHODS: In total, 185 lesions were identified on bone and SPECT-CT scans from 32 patients. Lesions were classified as metastatic (109 sclerotic lesions) and benign (76 lesions) morphologically on low-dose CT. Semiquantitative analysis using SUVmax and mean HU was performed on the lesions and compared. To discriminate benign and metastatic lesions, the correlation between SUVmax and mean HU was determined using the intraclass correlation coefficients.
RESULTS: The SUVmax was higher in metastatic lesions (20.66±14.36) but lower in benign lesions (10.18±12.79) (p<0.001). The mean HU was lower in metastatic lesions (166.62±202.02) but higher in benign lesions (517.65±192.8) (p<0.001). A weak negative correlation was found between the SUVmax and the mean HU for benign lesions, and a weak positive correlation was noted between the SUVmax and the mean HU on malignant lesions with no statistical significance (p=0.394 and 0.312, respectively). The cutoff values obtained were 10.8 for SUVmax (82.6% sensitivity and 84.2% specificity) and 240.86 for the mean HU (98.7% sensitivity and 88.1% specificity) in differentiating benign from malignant bone lesions.
CONCLUSIONS: Semiquantitative assessment using SUVmax and HU can complement qualitative analysis. Metastatic lesions had higher SUVmax but lower mean HU than benign lesions, whereas benign lesions demonstrated higher mean HU but lower SUVmax. A weak correlation was found between the SUVmax and the mean HU on malignant and benign lesions. Cutoff values of 10.8 for the SUVmax and 240.86 for the mean HU may differentiate bone metastases from benign lesions.

METHODS: A retrospective study.
OBJECTIVE: To investigate the correlation between Hounsfield unit (HU) values measured by chest computed tomography (CT) and dual-energy Xray absorptiometry (DXA) T-scores. HU-based thoracolumbar (T11 and T12) cutoff thresholds were calculated for a cohort of Chinese patients.
BACKGROUND: For patients with osteoporosis, the incidence of fractures in the thoracolumbar segment is significantly higher than that in other sites. However, most current clinical studies have focused on L1.
METHODS: This retrospective study analyzed patients who underwent chest CT and DXA at our hospital between August 2021 and August 2022. Thoracic thoracolumbar segment HU values, lumbar T-scores, and hip T-scores were computed for comparison, and thoracic thoracolumbar segment HU thresholds suggestive of potential bone density abnormalities were established using receiver operating characteristic curves.
RESULTS: In total, 470 patients (72.4% women; mean age, 65.5±12.3 years) were included in this study. DXA revealed that of the 470 patients, 90 (19%) had osteoporosis, 180 (38%) had reduced osteopenia, and 200 (43%) had normal bone mineral density (BMD). To differentiate osteoporosis from osteopenia, the HU threshold was established as 105.1 (sensitivity, 54.4%; specificity, 72.2%) for T11 and 85.7 (sensitivity, 69.4%; specificity, 61.1%) for T12. To differentiate between osteopenia and normal BMD, the HU threshold was 146.7 for T11 (sensitivity, 57.5%; specificity, 84.4%) and 135.7 for T12 (sensitivity, 59.5%; specificity, 80%).
CONCLUSIONS: This study supports the significance of HU values from chest CT for BMD assessment. Chest CT provides a new method for clinical opportunistic screening of osteoporosis. When the T11 HU is >146.7 or the T12 HU is >135.7, additional osteoporosis testing is not needed unless a vertebral fracture is detected. If the T11 HU is <105.1 or the T12 HU is <85.7, further DXA testing is strongly advised. In addition, vertebral HU values that fall faster than those of the T11 and L1 vertebrae may explain the high incidence of T12 vertebral fractures.

In this study tissue equivalency of the polymeric materials was investigated by comparing with ICRP 110 Male Adult Computational Phantom tissues. For this purpose, radiological properties of polyamide (PA), high density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMWPE), polypropylene (PP), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyoxymethylene (POM) and polyurethane foam (PU FOAM) were evaluated in the diagnostic energy range (15-150 keV). The radiological properties of the materials and ICRP 110 Male and Female Adult Computational Phantom tissues were calculated with Phy-X/PSD software. No major differences were seen except for sex-specific organs, and comparisons were made using an adult male phantom. To confirm the results experimentally, a chest phantom was designed with the polymeric materials. The phantom was scanned by Siemens SOMATOM Edge CT device with tube voltage of 120 kVp and Hounsfield Unit (HU) values were measured. In addition, HU values were calculated using theoretical relationships and significant agreement was obtained between measured and calculated HUs. It was determined that PA, PP, UHMWPE and HDPE were equivalent to muscle and adipose tissue, PVC and PTFE were equivalent to mineral bone, PET and POM were equivalent to spongiosa bone and PU FOAM was equivalent to lung tissue.

UNASSIGNED: Information about the range of Hounsfield values for healthy teeth tissues could become an additional tool in assessing dental health and could be used, among other data, for subsequent machine learning.
UNASSIGNED: The purpose of our study was to determine dental tissue densities in Hounsfield units (HU).
UNASSIGNED: The total sample included 36 healthy children (n=21, 58% girls and n=15, 42% boys) aged 10-11 years at the time of the study. The densities of 320 teeth tissues were analyzed. Data were expressed as means and SDs. The significance was determined using the Student (1-tailed) t test. The statistical significance was set at P<.05.
UNASSIGNED: The densities of 320 teeth tissues were analyzed: 72 (22.5%) first permanent molars, 72 (22.5%) permanent central incisors, 27 (8.4%) second primary molars, 40 (12.5%) tooth germs of second premolars, 37 (11.6%) second premolars, 9 (2.8%) second permanent molars, and 63 (19.7%) tooth germs of second permanent molars. The analysis of the data showed that tissues of healthy teeth in children have different density ranges: enamel, from mean 2954.69 (SD 223.77) HU to mean 2071.00 (SD 222.86) HU; dentin, from mean 1899.23 (SD 145.94) HU to mean 1323.10 (SD 201.67) HU; and pulp, from mean 420.29 (SD 196.47) HU to mean 183.63 (SD 97.59) HU. The tissues (enamel and dentin) of permanent central incisors in the mandible and maxilla had the highest mean densities. No gender differences concerning the density of dental tissues were reliably identified.
UNASSIGNED: The evaluation of Hounsfield values for dental tissues can be used as an objective method for assessing their densities. If the determined densities of the enamel, dentin, and pulp of the tooth do not correspond to the range of values for healthy tooth tissues, then it may indicate a pathology.