Quantitative Computed Tomography Research Articles

Comparative effectiveness of four techniques for identifying vertebral fragility fractures among elderly patients.

The incidence of vertebral fragile fractures peaked among the elderly population, and identifying individuals at high risk of vertebral fractures and promptly instituting preventions are of critical importance. This study aims to determine the efficacy and values of Hounsfield unit (HU) values, vertebral bone quality (VBQ) scores, bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA), and quantitative computed tomography (QCT) to discriminate between patients with and without vertebral fractures. A thorough search was conducted across PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, and Wan Fang Database to identify potential studies that met the eligibility criteria. Studies that evaluated the utility of HU values, VBQ scores, QCT-measured BMD, and DXA-measured BMD in discriminating vertebral fractures were qualified. The combined results showed that there were significant differences in HU values, VBQ scores, QCT-measured BMD, and DXA-measured BMD between the fracture and non-fracture groups. Moreover, the pooled sensitivity, specificity, and AUC of HU values were 0.82, 0.67, and 0.76, respectively; the pooled sensitivity, specificity, and AUC of VBQ scores were 0.70, 0.75, and 0.78; the pooled sensitivity, specificity, and AUC of QCT-measured BMD were 0.85, 0.76 and 0.88. All four methods, namely HU values, VBQ scores, QCT-measured BMD, and DXA-measured BMD can effectively distinguish between patients with and without vertebral fragile fractures. Among these, QCT-measured BMD exhibited a relatively high efficacy in discriminating vertebral fractures. VBQ scores and HU values demonstrated comparable efficacy for discriminating vertebral fractures among elderly patients. Question Can four different imaging modalities effectively discriminate vertebral fragility fracture status among elderly patients? Findings These methods can effectively distinguish vertebral fractures status among elderly patients, and quantitative computed tomography (QCT)-measured bone mineral density (BMD) exhibited a relatively high efficacy. Clinical relevance The clinical applications of Hounsfield unit values, vertebral bone quality scores, and BMD measured by dual-energy X-ray absorptiometry and QCT show promising outcomes in identifying individuals at high risk of vertebral fractures.

Associations of Habitual Skeletal Loading with Bone Changes During the Menopausal Transition: A Follow-up Study.

While weight-bearing physical activity (PA) benefits bone health, it remains unclear whether PA can counteract hormone-driven menopausal bone deterioration. This secondary analysis of a population-based prospective follow-up study examined changes in bone health indicators around menopause and evaluated whether accelerometer-measured habitual skeletal loading is associated with these changes. A total of 189 initially perimenopausal women without estrogen therapy (mean age 52 [SD 2] years) were followed until they became postmenopausal (mean follow-up time 15 [9] months). Femoral neck bone mineral density (FN BMD) and bone mineral content (BMC) were measured with dual x-ray absorptiometry (DXA). Femoral and tibial shaft volumetric BMD (vBMD), cross-sectional geometry, and stress-strain index (SSI) were assessed using quantitative computed tomography (QCT) in a subset of 61 women. Habitual skeletal loads (mean daily osteogenic index [OI] and low, medium, and high-intensity impact counts) were evaluated with multiple-day free-living accelerometry records. Longitudinal associations of habitual skeletal loads and bone outcomes were analyzed with GEE models. Consistent decreases were observed in FN BMD and BMC, and femoral and tibial shaft vBMD and SSI (p < 0.001) over the follow-up. Slight decreases over the follow-up were also observed in OI and medium impacts in the full sample, and medium and high impact counts in the subsample (p < 0.05). Medium impacts were associated with tibial shaft vBMD and SSI (β = 0.204, 95% CI [0.018, 0.391] and β = 0.077 95% CI [0.000, 0.154], respectively). High impacts were associated with femoral shaft vBMD (β = 0.186 95% CI [0.006, 0.366]. However, no association was observed between habitual skeletal loads and changes in bone characteristics over the follow-up. We observed a rather uniform skeletal response to the menopausal transition at all measured bone sites. Positive associations were found between medium and high-intensity impacts and bone characteristics at the femoral and tibial shafts. However, habitual skeletal loading did not seem to counteract bone deterioration during the menopausal transition.

Effects of acute-phase COVID-19-related indicators on pulmonary fibrosis and follow-up evaluation

BackgroundPost-COVID-19 pulmonary fibrosis is a significant long-term respiratory morbidity affecting patients’ respiratory health. This exploratory study aims to investigate the incidence, clinical characteristics, and acute-phase risk factors for pulmonary fibrosis in COVID-19 patients. Additionally, it evaluates pulmonary function and chest CT outcomes to provide clinical evidence for the early identification of high-risk patients and the prevention of post-COVID-19 pulmonary fibrosis.MethodsWe retrospectively analyzed 595 patients hospitalized for COVID-19 from January 2022 to July 2023. Patients were divided into fibrosis and nonfibrosis groups on the basis of imaging changes. Baseline data, including demographics, disease severity, laboratory indicators, and chest imaging characteristics, were collected. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for pulmonary fibrosis. Pulmonary function and chest CT follow-ups were conducted for the fibrosis group. The data were processed via SPSS 26.0, with P < 0.05 considered statistically significant.ResultsThe incidence of pulmonary fibrosis was 4.37%, with 2.08% in moderate cases and 8.22% in severe cases. Significant differences were found between the fibrosis and nonfibrosis groups in sex; disease severity; NLR; ALB and LDH levels; and percentages of lung reticular lesions, consolidations, and GGOs (P < 0.05). Multivariate analysis revealed LDH (OR = 1.004, 95% CI 1.000–1.007, P = 0.035), ALB (OR = 0.871, 95% CI 0.778–0.974, P = 0.015), lung reticular lesion volume (OR = 1.116, 95% CI 1.040–1.199, P = 0.002), and lung consolidation volume (OR = 1.131, 95% CI 1.012–1.264, P = 0.030) as independent risk factors. The follow-up results revealed significant improvements in pulmonary function, specifically in the FVC%, FEV1%, and DLCO%, but not in the FEV1/FVC. Quantitative chest CT analysis revealed significant differences in lung reticular lesions, consolidation, and GGO volumes but no significant difference in honeycomb volume.ConclusionsThe incidence of pulmonary fibrosis post-COVID-19 increases with disease severity. LDH, ALB, lung reticular lesions, and consolidation volume are independent risk factors for patients with fibrosis.

Automated bone property analysis using corrected in vivo dental cone-beam CT data of human wrists

Fracture liaison services are essential to mitigate underdiagnosis and undertreatment of osteoporosis-related fractures. However, it often suffers from limited access to dual-energy X-ray absorptiometry (DXA) or high-resolution peripheral quantitative CT equipment. This in vivo study of 21 patients aims to evaluate the feasibility of dental cone beam CT (dCBCT) to analyse bone properties of human wrists, comparing with DXA and finite element (FE) analysis. dCBCT grey-scale values were transformed to HU using a phantom containing materials with known HU values. Strong correlations were found between bone mineral content (BMC) from dCBCT and DXA (r = 0.78 to 0.84, p < 0.001), as well as between BMC from dCBCT FE-predicted stiffness (r = 0.91) and maximum force (r = 0.93), p < 0.001. BMC values from dCBCT were higher than DXA measurements (2.34 g vs. 1.5 g, p < 0.001). Cortical thickness strongly correlated to bone mineral density (BMD) from dCBCT (r = 0.83, p < 0.001). No statistically significant correlations were found between trabecular bone microstructure and FE predictions. The results indicate the feasibility to analyse osteoporosis related bone properties of human wrists from corrected dCBCT data. The dCBCT values of BMD and BMC were strongly correlated with DXA.

Comparative evaluation of trabecular bone density in Hounsfield units in the lumbar native CT cross-section for osteoporosis diagnosis and fracture risk determination by different examiners

An increasing loss of bone mineral density (BMD) in the axial skeleton leads to osteoporosis and fractures, with an increase found in the thoracic and thoracolumbar regions. The extent to which an examiner-independent assessment of the extent of osteoporosis and fracture risk determination is possible by determining the trabecular density in Hounsfield units (HU) in the spine should be examined. The next question was whether quantitative BMD values can be calculated from the HU values. 225 patients (pt.) with an average age of 64.9 ± 13.1 years and abody-mass-index (BMI) of 26.8 ± 6.8 kg/m2, of which 37were men and 188 were women, were examined to determine whether they had osteoporosis. The BMD was determined in mg/cm3 using quantitative computed tomography (QCT) in the lumbar region. After anonymization by three experienced radiologists, an additional measurement of the trabecular bone density in HU, was carried out in the same vertebral bodies (atotal of 675 vertebral bodies), each using aregion of interest (ROI) positioned in the midvertebral cancellous space in the sagittal reformed CT image. In additional lateral X‑rays of the thoracic and lumbar spine, vertebral fractures were detected and graded. Sacral insufficiency fractures that occurred at the same time were also recorded. The median BMD was 73.2 (57.05-104.17) mg/cm3 and the median HU was 89.93 (67.90-126.95). With acorrelation of 0.988 (p < 0.001), quantitative values in mg/cm3 can be calculated using the following formula: Xq = 12.1 + 0.68 × HU. With HU values less than 69.84 and aBMD of the lumbar spine below 59.54 mg/cm3, there was asignificantly increased number of OVF. At least one OVF was found in 137/225 pt. In 17/137 pt., sacral fractures were also found; these patients showed the significantly lowest values with amedian BMD of 41.81 (16.2-53.7) mg/cm3. Comparable HU values were determined independently of the examiners (p > 0.05). The trabecular density measurements in HU values can be converted into quantitative BMD values in mg/cm3, which enables agood assessment of osteoporosis and fracture risk. Taking the results obtained into account, an opportunistic evaluation using HU values in native CT alone seems quite possible. Experienced examiners have arrived at comparable results.

Untreated Osteoporosis in Lumbar Fusion Surgery Patients: Prevalence, Risk-factors and Effect on Bone Metabolism.

Secondary analysis of a prospective single-center study. To analyze the prevalence and risk factors for untreated osteoporosis in patients undergoing lumbar spinal fusion surgery (LFS) and its impact on bone mineral density (BMD) and bone turnover markers. Osteoporosis is a risk factor for mechanical complications in LFS, which can be mitigated by antiosteoporotic treatment. However, there's limited research on factors leading to untreated osteoporosis before LFS and its impact on preoperative bone status. A secondary analysis of a prospective study enrolling adults undergoing LFS for degenerative conditions (2014-2024) with preoperative quantitative CT osteoporosis screening was performed. Demographic data and medical history were analyzed for prevalence and risk factors of untreated osteoporosis, while BMD, vitamin D, PTH levels, and bone turnover markers were assessed for the effects of lacking treatment. A total of 445 patients (48% female, median age 64) were included, of which 137 patients (31%) had osteoporosis. Of these, 66 (48%) were untreated and 71 (52%) were treated, with 40 (56%) receiving pharmacological and 31 (44%) non-pharmacologic treatment including vitamin D supplementation and lifestyle modifications. Of the untreated patients, 55 (80%) were identified by preoperative screening. 71% of osteoporotic men versus 35% of osteoporotic women were untreated (P<0.001). Multivariable logistic regression confirmed male sex as an significant contributing factor (OR 4.3, 95% CI 1.9-10.1, P<0.001) for untreated osteoporosis. Treated osteoporotic patients had higher BMD (P<0.001), higher VitD levels P=0.023) and lower levels of bone resorption parameters (P=0.004) than untreated patients. Untreated osteoporosis is common before LFS, especially in men, with the untreated having lower BMD and higher bone resorption marker levels than treated patients. Identification of osteoporotic cases and subsequent osteological optimization could potentially reduce the risks of adjacent fractures or screw loosening.

Development of a machine learning model in prediction of the rapid progression of interstitial lung disease in patients with idiopathic inflammatory myopathy.

Rapidly progressive interstitial lung disease (RP-ILD) significantly impacts the prognosis of patients with idiopathic inflammatory myopathies (IIM). High-resolution computed tomography (HRCT) is a crucial noninvasive technique for evaluating interstitial lung disease (ILD). Utilizing quantitative computed tomography (QCT) enables accurate quantification of disease severity and evaluation of prognosis, thereby serving as a crucial computer-aided diagnostic method. This study aimed to establish and validate a machine learning (ML) model to predict RP-ILD in patients with idiopathic inflammatory myopathy-related interstitial lung disease (IIM-ILD) based on QCT and clinical features. A total of 514 patients (367 females, median age 54 years) with IIM-ILD in the China-Japan Friendship Hospital were retrospectively included, out of which 249 cases (165 females, median age 55 years) were identified as having RP-ILD. To extract the quantitative features on HRCT, deep learning (DL) methods were employed, along with demographic factors, pulmonary function test results, and blood gas analysis results; these factors were integrated into a final prediction model. Logistic regression was chosen as the final model due to its superior area under the curve (AUC) and explainability compared to the other seven ML models. The validation dataset yielded an AUC of 0.882 [95% confidence interval (CI): 0.797-0.967], indicating that the combined QCT and clinical features model outperformed both the QCT-only model and the clinically-only model. In calibration and clinical decision curve analysis, the final model demonstrated minimal prediction bias (concordance index: 0.887, 95% CI: 0.800-0.974, P<0.001) and provided greater net benefit across most thresholds. The nomogram encompassed the incorporation of the following variables: subtype, gender, forced expiratory volume in one second (FEV1%), diffusing capacity for carbon monoxide (DLCO%), oxygenation index (OI), and quantitative ground-glass opacities (GGOs), consolidation, pulmonary vascular, and branches on HRCT. When utilizing ML techniques, the baseline QCT has the potential to predict rapid progression in patients with IIM-ILD. The prediction performance will be further improved by incorporating clinical data alongside HRCT features. Idiopathic inflammatory myopathy (IIM); rapidly progressive interstitial lung disease (RP-ILD); high-resolution computed tomography (HRCT); machine learning (ML); quantitative computed tomography (QCT).

Quantitative computed tomography analysis of proximal femur bone mineral density and its relation to hip fracture risk.

Hip fractures significantly reduce the quality of life and mobility of older adults. This study aimed to analyze the correlation between volumetric bone mineral density (vBMD) in different regions of the proximal femur as measured by quantitative computed tomography (QCT) and various subtypes of hip fractures. This case-control study included patients over the age of 65 years admitted to Huadong Hospital Affiliated to Fudan University for hip fractures from November 2022 to December 2023; additionally, patients from the health examination center or outpatient center treated during the same period were included as a control group. Age and gender were matched to eliminate potential confounding factors. The vBMD at the femoral neck (FN), intertrochanteric (IT), and subtrochanteric (ST) regions in the hip fracture groups [FN fracture (FNF) and IT fracture (ITF)] and control group were measured using QCT. A total of 107 patients with FNF, 77 with ITF, and 72 controls were included. After matching for age and gender was completed, 48 individuals were included in each of the three groups. The vBMD at the IT, FN, and ST regions were significantly lower in patients with hip fractures compared to those in the control group for both genders (P<0.001). The vBMD of the FN and IT regions of females in the ITF group was lower than that of those in the FNF group (P<0.05). Additionally, the vBMD of the ST region in both genders was lower in the ITF group than in the FNF group (male: P<0.05; female: P<0.001). In all three groups, females had a significantly lower vBMD in all three regions compared to males (P<0.001). The decline in vBMD was more pronounced in the ITF group than in the FNF group for both genders, with the largest reduction compared to controls observed in the ST region of females in the ITF group. Older adult individuals with a lower hip vBMD are more susceptible to experiencing osteoporotic hip fracture than are those with a normal vBMD. Reduced ST vBMD may serve as an indicator for ITF, especially among females.

Distinct physiological, transcriptomic, and imaging characteristics of asthma-COPD overlap compared to asthma and COPD in smokers

The clinical and pathological features of asthma and chronic obstructive pulmonary disease (COPD) can converge in smokers and elderly individuals as asthma-COPD overlap (ACO). This overlap challenges the diagnosis and treatment of the distinct aetiologies underlying these conditions. We analysed 2453 smokers (≥10 pack-years), aged 45-80 years, from the Genetic Epidemiology of COPD (COPDGene) Study, stratified as Control, Asthma, COPD, and ACO based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. A comprehensive assessment was performed, encompassing symptomatology, pulmonary function tests (PFTs), complete blood counts (CBCs), bulk RNA sequencing (RNA-seq), and high-resolution quantitative computed tomography (QCT) imaging to evaluate clinical impact, lung function, systemic inflammation, and structural alterations contributing to disease progression across respiratory phenotypes. Differential expression (DE) analysis was performed using whole blood RNA-seq (BH-corrected FDR < 0.01), followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Group differences were assessed using the Mann-Whitney U-test (MWU) or Chi-squared test (χ2), with Bonferroni correction applied for multiple comparisons. Multivariate linear regression models were used to adjust the associations between disease status and specific clinical outcomes for confounders, with one-way ANOVA and Tukey's Honest Significant Difference (HSD) post-hoc test applied for pairwise comparisons. Our analysis aimed to delineate the extent and variability of clinical features among disease phenotypes to guide targeted therapeutic strategies. Our study highlights distinct yet overlapping profiles across ACO, asthma, and COPD. We effectively isolated disease-specific mechanisms by comparing each phenotype to smoking controls (GOLD 0) while accounting for baseline smoking-related inflammation. ACO exhibited the most severe symptom burden, with significantly higher COPD Assessment Test (CAT) score (18.32, 95% CI: [17.02, 19.63], P<0.0001) and Modified Medical Research Council (mMRC) Dyspnea score (2.14, 95% CI: [1.92, 2.35], P<0.0001) compared to COPD and asthma. ACO also displayed reduced lung capacity (forced expiratory volume in 1s [FEV1]: 52.5%, 95% CI: [50.08, 54.93], P<0.0001) and airflow limitation (FEV1/forced vital capacity [FVC]: 0.55, 95% CI: [0.5471, 0.5546], P<0.0001), closely resembling COPD but significantly worse than asthma. The inflammatory profile of ACO exhibited a mixed response, featuring elevated neutrophil counts (4.57K/μL, 95% CI: [4.28, 4.86], P<0.0001) and eosinophil levels (0.22K/μL, 95% CI: [0.20, 0.25], P<0.01), contrasting with the predominantly neutrophilic inflammation in COPD and the absence of systemic inflammation in asthma. Structurally, ACO demonstrated significant airway remodelling (Pi10: 2.87, 95% CI: [2.83, 2.91], P<0.0001), intermediate emphysema (5.66%, 95% CI: [4.72, 6.60], P<0.0001), and moderate small airway disease (parametric response mapping for functional small airway disease [PRMfSAD]: 22.94%, 95% CI: [21.53, 24.34], P<0.0001), reflecting features of both asthma and COPD. COPD was characterised by more extensive emphysema (8.9%, 95% CI: [8.34, 9.45], P<0.0001), small airway disease (PRMfSAD: 27.09%, 95% CI: [26.51, 27.66], P<0.0001), and gas trapping (37.34%, 95% CI: [36.33, 38.35], P<0.0001), alongside moderate airway remodelling. At a molecular level, DE analysis revealed enrichment of the Hypoxia-Inducible Factor 1 (HIF-1) pathway in ACO, highlighting unique hypoxia-driven metabolic adaptations, while COPD was associated with neutrophil extracellular trap (NET) formation and necroptosis. In contrast, asthma exhibited significant airway remodelling (Pi10: 2.09, 95% CI: [2.05, 2.13], P<0.0001), minimal parenchymal damage, and no systemic gene expression changes. Collectively, our findings underscore the lung function impairments, systemic inflammation, molecular mechanisms, and structural correlates distinguishing ACO from COPD and asthma, emphasising the need for precise clinical management and the potential for novel therapeutic interventions. This work was supported by National Heart, Lung, and Blood Institute (NHLBI) grants U01 HL089897 and U01 HL089856, as well as by National Institutes of Health (NIH) contract 75N92023D00011. Additional support was provided by grants R01 HL166231 (C.P.H.) and K01 HL157613 (A.S.).

Combining computed tomography features of left atrial epicardial and pericoronary adipose tissue with the triglyceride-glucose index to predict the recurrence of atrial fibrillation after radiofrequency catheter ablation: a machine learning study.

Radiofrequency catheter ablation (RFCA) represents an important treatment option for atrial fibrillation (AF); however, the recurrence rate following surgery is relatively high. This study aimed to predict the recurrence of AF after RFCA using interpretable machine learning models that combined the triglyceride-glucose (TyG) index and the quantification of left atrial epicardial and pericoronary adipose tissue. This retrospective study included 325 patients with AF who underwent their first successful RFCA, among whom 79 had confirmed recurrence. The preoperative clinical data of patients were collected, the TyG index was calculated, and computed tomography (CT) image features were quantitatively measured. Multivariate Cox regression analysis was used to identify the independent risk factors for RFCA recurrence, and adjustments being made for various confounding factors. Post-hoc subgroup analysis was conducted to evaluate the predictive value of the TyG index for recurrence in different patient subgroups. Prediction models based on six machine learning algorithms were constructed. The optimal model's features were evaluated using Shapley additive explanations (SHAP). After adjustment were made for various confounding factors such as comorbidities of AF, Cox regression showed that the volume of left atrial epicardial adipose tissue (LA-EAT), LA-EAT attenuation, left circumflex coronary artery fat attenuation index (LCX-FAI), and the TyG index were independent risk factors for recurrence after RFCA (P<0.001). The support vector machine (SVM) model based on these combined indicators had the best predictive performance, with an area under the curve of 0.793 [95% confidence interval (CI): 0.782-0.805] in the validation set, while its accuracy and positive predictive value were 0.804 and 0.710, respectively. The predictive efficiency of the TyG index appeared to be independent of type 2 diabetes mellitus (T2DM) status (Pinteraction=0.660). The SVM model that integrated the TyG index and quantitative CT imaging variables demonstrated good predictive ability for post-RFCA recurrence in patients with AF. Furthermore, the TyG index appeared capable of predicting recurrence independently of T2DM status.

Prognostic Implications of Regional Lung Impairment Evaluation in Quantitative CT Imaging of COVID-19

Prognostic Implications of Regional Lung Impairment Evaluation in Quantitative CT Imaging of COVID-19

Skeletal effects of sleeve gastrectomy, by sex and menopausal status and compared to Roux-en-Y gastric bypass surgery.

Roux-en-Y gastric bypass (RYGB) has deleterious effects on bone mass, microarchitecture, and strength. The skeletal effects of sleeve gastrectomy (SG), now the most commonly performed bariatric surgical procedure, are incompletely understood. We examined changes in bone turnover, areal and volumetric bone mineral density (aBMD, vBMD), and appendicular bone microarchitecture and estimated strength after SG. We compared the results to those previously reported after RYGB, hypothesizing lesser effects after SG than RYGB. Prospective observational cohort study of 54 adults with obesity undergoing SG at an academic center. Skeletal characterization with biochemical markers of bone turnover, dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and high-resolution peripheral QCT (HR-pQCT) was performed preoperatively and 6- and 12-months postoperatively. Over 12 months, mean percentage weight loss was 28.8%. Bone turnover marker levels increased, and total hip aBMD decreased -8.0% (95% CI -9.1%, -6.7%, p<0.01). Spinal aBMD and vBMD declines were larger in postmenopausal women than men. Tibial and radial trabecular and cortical microstructure worsened, as did tibial estimated strength, particularly in postmenopausal women. When compared to data from a RYGB cohort with identical design and measurements, some SG biochemical, vBMD, and radial microstructural changes were smaller, while other changes were not. Bone mass, microstructure, and strength decrease after SG. Some skeletal parameters change less after SG than after RYGB, while for others, we find no evidence for smaller effects after SG. Postmenopausal women may be at highest risk of skeletal consequences after SG.

Does the Intensity of Therapy Correspond to the Severity of Acute Respiratory Distress Syndrome (ARDS)?

Objectives: The intensity of respiratory treatment in acute respiratory distress syndrome (ARDS) is traditionally adjusted based on oxygenation severity, as defined by the mild, moderate, and severe Berlin classifications. However, ventilator-induced lung injury (VILI) is primarily determined by ventilator settings, namely tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP). All these variables, along with respiratory elastance, are included in the concept of mechanical power. The aim of this study is to investigate whether applied mechanical power is proportional to oxygenation severity. Methods: We analyzed 291 ARDS patients (71 mild, 155 moderate, and 65 severe). We defined low, middle, and high mechanical power by dividing the entire population into tertiles with a similar number of patients. In each oxygenation class, we measured computed tomography (CT) anatomy, gas exchange, respiratory mechanics, mechanical power, and mortality rate. Results: ARDS severity was proportional to lung anatomy impairment, as defined by quantitative CT scans (i.e., lung volume and well-aerated tissue decreased across the ARDS classes, while respiratory elastance increased, as did mortality). Mechanical power, however, was similarly distributed across the severity classes, as the decrease in tidal volume in severe ARDS was offset by an increase in respiratory rate. Within each ARDS class, mortality increased from low to high mechanical power (roughly 1% for each J/min increase). Conclusions: Both lung severity and mechanical power independently impact mortality rates. It is tempting to speculate that ARDS severity primarily reflects the natural course of the disease, while mechanical power primarily reflects the risk of VILI.

Quantification of Interstitial Lung Diseases, From the AJR Special Series on Quantitative Imaging.

High-resolution CT (HRCT) plays an important role in diagnosing and monitoring interstitial lung diseases (ILDs). Despite advances, predicting disease progression and treatment response remains challenging. HRCT enables noninvasive visualization and classification of patterns of lung injury and assessment of disease extent. Visual estimation of CT extent of fibrotic lung disease is an independent predictor of mortality and progression, but is subjective, with only modest interobserver agreement for radiologic interpretation of ILD. Machine learning-based textural analysis of fibrosis extent on baseline and serial HRCT scans shows robust correlations with physiologic measures and strong association with risk of disease progression or mortality across various fibrosing ILDs. In idiopathic pulmonary fibrosis, quantitative CT (QCT) assessment is associated with physiologic impairment and risk of progression and death, and increasing severity of fibrosis on longitudinal evaluation is associated with increased risk of progression and death. Similar results have been noted for fibrotic hypersensitivity pneumonitis and connective tissue disease. This review focuses on QCT techniques for ILDs. We describe the clinical need for quantification of lung disease and illustrate the role of conventional visual evaluation and of QCT approaches in defining disease severity, prognosis, and longitudinal progression, both in established disease and in preclinical interstitial abnormality.

The application of QCT in the prognostic assessment of mCRC undergoing first-line treatment based on bevacizumab.

Bevacizumab induces muscle atrophy by changing the gene expression level of muscle tissue. Quantitative computed tomography (QCT) enables precise measurement of various body compositions, including muscle area. A total of 102 patients with metastatic colorectal cancer (mCRC) undergoing first-line chemotherapy based on bevacizumab were enrolled at thirst Affiliated Hospital of the University of Science and Technology of China. Their body compositions were measured respectively 1 month before and 1 month after the treatment. Treatment-related decline in skeletal muscle index and visceral fat infiltration significantly affect patient prognosis. A predictive model constructed by integrating changes in body composition with patient clinical characteristics effectively predicts the 9-month progression-free survival (PFS) of patients with mCRC.

Effect of adipose tissue deposition on insulin resistance in middle-aged and elderly women: Based on QCT and MRI mDIXON-Quant.

To explore the relationship between adipose tissue deposition and triglyceride-glucose (TyG) index, an indicator clinically used to assess insulin resistance (IR), in middle-aged and elderly women using quantitative computed tomography (QCT) and MRI mDIXON-Quant sequence. All participants underwent quantitative computed tomography (QCT) and MRI mDIXON-Quant examination and calculated the TyG index based on the fasting blood glucose and triacylglycerol. Bounded by the median TyG index, all participants were divided into low TyG group and high TyG group. Visceral fat mass (VFM) and subcutaneous fat mass (SFM) were measured on QCT images. Hepatic proton density fat fraction (H-PDFF), pancreatic proton density fat fraction (P-PDFF), and lumbar bone marrow fat fraction (L-BMFF) were measured on MRI mDIXON-Quant images. Adjusting for age and body mass index (BMI), TyG was moderately positively correlated with H-PDFF, and r/P was 0.416/<0.001, TyG index was weakly positively correlated with VFM and P-PDFF, and r/P were 0.385/<0.001 and 0.221/0.030. There was a difference of VFM, H-PDFF, and P-PDFF between low TyG group and high TyG group (P < 0.05). Adjusting for age and BMI, VFM, and H-PDFF were the risk factors of high TyG, and H-PDFF was the independent risk factor of high TyG. VFM and H-PDFF were the risk factors of IR, and H-PDFF was the independent risk factor. Early identification and active treatment of adipose tissue deposition, especially hepatic fat deposition, may reserve and delay the progression of IR and even metabolic syndrome.

Abstract 4135636: Age- and Sex-Related Coronary Atherosclerosis by Artificial Intelligence Quantitative Coronary CT Angiography from the INVICTUS Registry

Background: Coronary plaque analysis using artificial intelligence quantitative coronary CT (AI-QCT) is a promising tool to identify coronary atherosclerosis. However, there is insufficient data on coronary atherosclerosis volume and morphology using AI-QCT in patients who are at high risk of atherosclerosis. The purpose of this study is to clarify the differences in the volume and phenotypes of coronary atherosclerosis by age and gender using AI-QCT. Methods: The INVICTUS Registry is a multi-center registry enrolling patients who clinically underwent coronary CT angiography and invasive coronary angiography with invasive imaging modalities in Japan. Patients with a history of percutaneous coronary intervention or coronary artery bypass graft were excluded in this study. Using AI-QCT, the volume, and phenotypes (calcified, non-calcified, low-density non-calcified plaque [LD-NCP]) of coronary atherosclerosis were analyzed and assessed by age (&lt;55, 55-64, 65-74, and 75 and older) and gender. Results: A total of 982 patients were enrolled in the study. The mean age was 70.3 ± 10.8 years, 71.9% were male. Approximately two-thirds of patients had hypertension (73.3%) and dyslipidemia (71.5%), and 36.7% had diabetes. Mean total plaque volume (PV), calcified PV, non-calcified PV, and low-density PV were 745.5±529.8 mm 3 , 248.3±302.0 mm 3 , 482.2±340.6 mm 3 , and 15.0±29.4 mm 3 , respectively. The results of plaque volume and phenotypes by age are shown in the figure. Compared to those under 55 years of age, total PV increased gradually and significantly by about 10% for every 10 years of age (p=0.022). Though no significant difference was observed in non-calcified PV between the age groups (p=0.379), calcified PV progressively and significantly increases approximately 70% for every 10 years of age (p&lt;0.001). In contrast, the low-density plaque volume showed a trend toward a significant decrease with increasing age (p=0.073). These trends did not differ by gender. Conclusion: In a large cohort of patients at high risk for atherosclerosis analyzed by AI-QCT, total coronary PV increased with age, primarily calcified PV. While no change in non-calcified PV between the age groups, LD-NCPV was likely to decrease with increasing age. These findings may contribute to the guidance for the prevention of coronary artery diseases based on coronary atherosclerosis phenotype by age and gender.

Abstract 4144554: Revascularization of Patients with Low-Density Non-Calcified Plaque was Associated with Lower Occurrence of Acute Coronary Syndrome

INTRODUCTION: Coronary CT angiography (CCTA) is a powerful noninvasive tool for identifying high-risk plaque, such as low-density non-calcified plaque (LD-NCP). Though, the optimal treatment of patients with LD-NCP remains unclear. This study explored the association of revascularization in the setting of LD-NCP with the occurrence of acute coronary syndrome (ACS). Methods: This was a post-hoc analysis of the ICONIC study. A subset of 234 patients that underwent CCTA with subsequent ACS were matched to 234 control patients who also underwent CCTA but did not have ACS during follow-up. Patients were also followed for occurrence of revascularization, either coronary artery bypass graft or percutaneous coronary intervention. Atherosclerosis imaging-enabled quantitative CT (AI-QCT) was used to measure diameter stenosis, and LD-NCP, non-calcified plaque, and calcified plaque volumes from each CCTA. LD-NCP was defined as plaque with -190 to 30 Hounsfield Units. Patients were stratified based on the presence of LD-NCP. Subgroup analysis was conducted to compare the occurrence of ACS with the rate of revascularization. Kaplan-Meier survival curves and extended Cox regression analysis were used to evaluate the effect size of revascularization and LD-NCP on occurrence of ACS. Results: AI-QCT was completed in 448/468 subjects (follow-up time [MEAN±SD] 2.44±2.48 years). The median of LD-NCP was 1.2 mm 3 for patients with &gt;0 mm 3 LD-NCP. There were 85 patients with LD-NCP &gt;1.2 mm 3 and 363 patients with LD-NCP ≤1.2 mm 3 . In patients with LD-NCP &gt;1.2 mm 3 , the rate of revascularization in patients with and without ACS was 3/52 (5.8%) versus 14/33 (42.4%) (p&lt;0.001). In patients with LD-NCP ≤1.2 mm 3 , the rate of revascularization in patients with and without ACS was 36/170 (21.2%) versus 39/193 (20.2%) (p=0.897). In comparison to patients without revascularization and LD-NCP ≤1.2 mm 3 , patients with LD-NCP &gt;1.2 mm 3 and revascularization were less likely to have ACS during follow-up (adjusted HR: 0.20 [0.07, 0.61]; p=0.005). Additionally, patients with LD-NCP &gt;1.2 mm 3 who did not undergo revascularization were more likely to have ACS (adjusted HR: 1.47 [1.03, 2.12]; p=0.036). Hazard ratios were adjusted for diameter stenosis, and non-calcified and calcified plaque volume. Time-dependent coefficients were included for diameter stenosis. Conclusion: Revascularization of patients with LD-NCP &gt;1.2 mm 3 identified on CCTA with AI-QCT was associated with less risk for ACS.

Utilizing artificial intelligence to determine bone mineral density using spectral CT

BackgroundDual-energy computed tomography (DECT) has demonstrated the feasibility of using HAP-water to respond to BMD changes without requiring dedicated software or calibration. Artificial intelligence (AI) has been utilized for diagnosising osteoporosis in routine CT scans but has rarely been used in DECT. This study investigated the diagnostic performance of an AI system for osteoporosis screening using DECT images with reference quantitative CT (QCT). MethodsThis prospective study included 120 patients who underwent DECT and QCT scans from August to December 2023. Two convolutional neural networks, 3D RetinaNet and U-Net, were employed for automated vertebral body segmentation. The accuracy of the bone mineral density (BMD) measurement was assessed with relative measurement error (RME%). Linear regression and Bland–Altman analyses were performed to compare the BMD values between the AI and manual systems with those of the QCT. The diagnostic performance of the AI and manual systems for osteoporosis and low BMD was evaluated using receiver operating characteristic curve analysis. ResultsThe overall mean RME% for the AI and manual systems were − 15.93 ± 12.05 % and − 25.47 ± 14.83 %, respectively. BMD measurements using the AI system achieved greater agreement with the QCT results than those using the manual system (R2 = 0.973, 0.948, p < 0.001; mean errors, 23.27, 35.71 mg/cm3; 95 % LoA, −9.72 to 56.26, −11.45 to 82.87 mg/cm3). The areas under the curve for the AI and manual systems were 0.979 and 0.933 for detecting osteoporosis and 0.980 and 0.991 for low BMD. ConclusionThis AI system could achieve relatively high accuracy for automated BMD measurement on DECT scans, providing great potential for the follow-up of BMD in osteoporosis screening.

Endobronchial valve treatment improves chest-CT diaphragm configuration in COPD

This study investigated the impact of bronchoscopic lung volume reduction treatment using endobronchial valves (EBV) on diaphragm configuration. We successfully analyzed the diaphragm index using a newly developed quantitative computed tomography (QCT) tool before and after EBV treatment in forty patients with severe emphysema. We evaluated whether changes in the diaphragm index were associated with improvements in forced expiratory volume in 1 s (FEV1), residual volume (RV), Saint Georges Respiratory Questionnaire (SGRQ), and 6-min walking distance (6MWD) using Spearman's rho. The EBV treatment influenced the diaphragm configuration only on the treated side, resulting in an increased diaphragm curvature. There were significant associations of relative diaphragm index changes on the treated lung side or the entire diaphragm with improvements in FEV1 and 6MWD. These findings provide valuable insights into how EBV treatment affects the diaphragm in COPD patients.