Value Of Computed Tomography Research Articles

Experimental study on the effects of different exposure conditions and contrast agent concentrations on spectral computed tomography virtual non-contrast images.

The early diagnosis of thrombosis and fat embolism is important for subsequent treatment regimens. Spectral computed tomography (CT) virtual non-contrast (VNC) scanning can not only accurately diagnose thrombosis and medium fat embolism but can also reduce the radiation dose and scanning time. However, there is a relative paucity of studies on what contrast concentration and exposure conditions are best for the quality of VNC images. To address this issue, this study aimed to investigate the effects of different exposure conditions and contrast concentrations on the quality of VNC images of low-density substances in spectral CT. Four solution groups [i.e., groups A (15 mgI/mL), B (10 mgI/mL), C (5 mgI/mL), and D (the control group)] were matched with normal saline and contrast agent groups. Four groups of solution, duck blood clots, and fat were injected into four sections of the pig large intestine, respectively. CT scans with different exposure amounts were performed under the condition of 120 KV. Comparing the true non-contrast (TNC) image based on solution D group with the VNC images of the other three solution groups. The differences in the CT values, standard deviation (SD) values, and contrast noise ratio (CNR) values of the duck blood and fat under different iodine concentrations and exposures were compared. The image quality was evaluated using a three-point method and the Kappa consistency test was performed. The consistency of the tissue CT values in the TNC and VNC images was analyzed by drawing Bland-Altman scatter plots. The CT values of the duck blood in the VNC20mAs and VNCC groups were lower than those in the TNC groups (P<0.05). Under different exposures and contrast agent concentrations, the CT value of the fat in the VNC group was higher than that in the TNC group (P<0.05). The SD values of the duck blood and fat in three groups (i.e., groups A, B, and C) were lower than those in the TNC group (P<0.05). The CNR value of the duck blood in the VNC20mAs group was lower than that in the TNC group (Z=-2.10, P=0.04), and the CNR values of the duck blood and fat in the VNC group were higher than those in the TNC groups in the remaining different exposure and concentration groups (P<0.05). The CT values of the lesions in the two groups were consistent, and there were no statistically significant differences between the subjective scores of the TNC and VNC images (z=-1.34, P=0.18); the subjective evaluations of the two physicians had good consistency (K=0.80). Under the conditions of higher contrast agent concentrations and proper exposure conditions, the VNC images were better able to restore the CT values of the blood clots, reduce the SD values of the blood clots and fat. In addition, and improve the CNR values of the blood clots and fat. In addition, the quality of the two images was similar.

Impact of Stone CT Value on Ureteroscopic Holmium Laser Lithotripsy Outcomes in Kidney Stone Treatment.

Kidney stone disease (KSD) is a prevalent and significant global urological issue, and ureteroscopic holmium laser lithotripsy (UHLL) is a primary treatment option. This study aimed to assess the impact of stone computed tomography (CT) value on the outcomes of UHLL in treating KSD. A retrospective analysis was conducted on the clinical data of 101 patients who underwent UHLL at our hospital between September 2022 and December 2023. Patients were categorised into two groups based on stone CT values. Demographic characteristics, intraoperative factors, stone clearance, and complications were evaluated and compared between the low- and high-CT groups. The high-CT group had significantly longer intraoperative durations than the low-CT group (p < 0.001). Fragmentation time was considerably higher in the high-CT group (p < 0.001). Stone clearance rates after three postoperative months were substantially higher in the low-CT group (98.04%) than in the high-CT group (84.00%) (χ2 = 4.523, p = 0.033). Although the low-CT group had a lower complication rate, the difference was insignificant (p = 0.356). CT values showed a positive correlation with durations of operation and fragmentation (p < 0.01), and a negative correlation with stone clearance (p < 0.05). Stone CT values are key factors influencing the procedural outcomes and postoperative complications of UHLL.

Advanced statistical analyses to reduce inconsistencies in bond strength data focused on donor factors: A six-factor analysis using linear mixed and nonlinear regression models.

This study aimed to investigate the effects of the age and sex of tooth donors on dentin bond strength. A total of 38 extracted teeth (12 male and 26 female donors; age range: 17-82 years) were used in this study. In addition to donor age and sex, four other microtensile bond strength (μTBS) test specimen factors were evaluated: dentin position, bonding area, presence of voids at the interface, and computed tomography (CT) values of dentin. The μTBS was measured immediately (24 h) and 6 months after storage in water. After the μTBS testing, linear mixed and nonlinear regression models were used to analyze the effects of these factors on the μTBS data. The results from the linear mixed model revealed that the bonding area (P = 0.02), presence of voids at the interface (P = 0.04), and storage time (P < 0.001) significantly affected bond strength. In contrast, no correlation was observed between the μ TBS and dentin position (P = 0.08) or sex (P = 0.07). The results of the nonlinear regression model with robust variance-covariance estimators revealed that age significantly affected bond strength (P < 0.001). In addition, a significant positive correlation was found between μTBS and age (P < 0.001), with nonlinearity (P = 0.002). However, no correlation was observed between the μTBS and CT values (P = 0.69) without nonlinearity (P = 0.39). These findings suggest that bond strength increases with age until 60 years but not afterward.

Artifact Assessment in the Skull Base Region of Head CT Images with Various Tilt Angles Relative to the Orbitomeatal Line

The aim of this study was to evaluate artifacts in the skull base region of head computed tomography (CT) images with various tilt angles relative to the orbitomeatal line. CT images of a head phantom acquired by helical and non-helical scanning with the tilt angles set from 0 to 20 degrees in 5-degree increments were evaluated in this study. Regions of interest (ROIs) were set at the cerebellum, temporal lobe, frontal lobe, and basal ganglia in the phantom images. Artifacts were evaluated by the coefficient of variation (CV) of the mean CT value between ROIs and the location parameter (β) of the Gumbel method. The CV and β values increased with increasing tilt angle for both helical and nonhelical images in the frontal lobes, but both decreased in the cerebellar region. In the temporal lobe and basal ganglia, there was no trend of change with tilt angle. Increasing the tilt angle relative to the OM line increased artifacts at the frontal lobes and decreased artifacts at the cerebellar region.

Feasibility of using 8 mL of iodinated contrast media in cerebral computed tomographic angiography with a dual-layer spectral detector.

Virtual monoenergetic images (VMIs) at a low energy level can improve image quality when the amount of iodinated contrast media (CM) is reduced. The purpose was to evaluate the feasibility of using an extremely low CM volume and injection rate in cerebral computed tomography angiography (CTA) on a dual-layer spectral detector computed tomography (CT). Patients who were clinically suspected of intracranial aneurysm or cerebrovascular diseases were included in our study (from June to November 2022). In this prospective study, 80 patients were randomly enrolled into group A (8 mL of CM with a 1-mL/s flow rate) or group B (40 mL of CM with 4-mL/s flow rate). The VMIs at 40-70 keV in group A and polychromatic conventional images in the 2 groups were reconstructed. CT attenuation, image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were evaluated via the t-test or Mann-Whitney test (2 groups), while analysis of variance or Kruskal-Wallis test (multiple groups). Subjective image quality was assessed on a 5-point scale. In group A, the subjective image quality score, CT attenuation, and CNR of the internal carotid artery (ICA) and middle cerebral artery (MCA) were the highest on VMIs at 40 keV. The image noise on VMIs at 40 keV was 5.08±0.84 Hounsfield units. The subjective image quality score, CT value of the ICA, MCA, and cerebral parenchyma on VMIs at 40 keV in group A were similar to those in group B (all P values >0.05). Compared to those in group B, the VMIs at 40 keV in group A demonstrated a significantly higher mean SNR and CNR of the ICA (mean SNR: 46.22±20.18 vs. 34.32±12.40, P=0.002; CNR: 55.47±13.43 vs. 46.18±12.30, P=0.002) and MCA [SNR: 13.66 (9.78, 20.29) vs. 9.99 (7.53, 14.00), P=0.003; CNR: 47.00±12.71 vs. 39.45±10.47, P=0.005]. Cerebral CTA on VMIs at 40 keV with 8 mL of CM and a 1-mL/s injection rate can provide diagnostic image quality.

Preliminary exploration of the correlation between spectral computed tomography quantitative parameters and spread through air spaces in lung adenocarcinoma.

The invasive pattern called spread through air spaces (STAS) is linked to an unfavorable prognosis in patients with lung adenocarcinoma (LUAD). Using computed tomography (CT) signs alone to assess STAS is subjective and lacks quantitative evaluation, whereas spectral CT can provide quantitative analysis of tumors. The aim of this study was to investigate the association between spectral CT quantitative parameters and STAS in LUAD. We retrospectively collected consecutive patients with LUAD who underwent surgical resection and preoperative spectral CT scan at our institution. The quantitative parameters included CT values at 40, 70, and 100 keV [CT40keVa/v, CT70keVa/v, and CT100keVa/v (a: arterial; v: venous)]; iodine concentration (ICa/ICv); normalized iodine concentration (NICa/NICv); and slope λHU of the spectral curve (λHUa/λHUv). Clinical and CT features of the patients were also collected. Statistical analysis was performed to identify the quantitative parameters, clinical and CT features that were significantly correlated with STAS status. We evaluated the diagnostic performance of significant factors or models which combined quantitative parameters and CT features, using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. We enrolled a total of 47 patients, with 32 positive and 15 negative for STAS. The results revealed that CT100keVa (P=0.002), CT100keVv (P=0.007), pathologic stage (P=0.040), tumor density (P<0.001), spiculation (P=0.003), maximum solid component diameter (P=0.008), and the consolidation/tumor ratio (CTR) (P=0.001) were significantly correlated with STAS status. The tumor density demonstrated a superior diagnostic capability [AUC =0.824, 95% confidence interval (CI): 0.709-0.939, sensitivity =59.4%, specificity =100.0%] compared to other variables. CT100keVa exhibited the best diagnostic performance (AUC =0.779, 95% CI: 0.633-0.925, sensitivity =78.1%, specificity =80.0%) among the quantitative parameters. Combination models were then constructed by combining the quantitative parameters with CT features. The total combined model showed the highest diagnostic efficiency (AUC =0.952, 95% CI: 0.894-1.000, sensitivity =90.6%, specificity =86.7%). Spectral CT quantitative parameters CT100keVa and CT100keVv may be potentially useful parameters in distinguishing the STAS status in LUAD.

Differential diagnosis of hepatocellular carcinoma and intrahepatic cholangiocarcinoma by ultrasonography combined with multiphase enhanced computed tomography.

Purpose: Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are primary liver cancers with different therapeutic methods and prognoses. This study aims to investigate the ultrasonography and enhanced computed tomography (CT) features of these cancers and improve the early diagnosis rate. Methods: We retrospectively analyzed the clinical and imaging data of 319 patients diagnosed with HCC and 124 patients diagnosed with ICC, confirmed by pathology. Results: A total of 443 patients were eligible in this study. From the perspective of clinical data, between HCC and ICC patients existed significant differences in age, gender, hepatic background, serum tumor markers of AFP and CA19.9, chronic hepatitis B/C and lymph node infiltration (p<0.05), but not in tumor size, microvascular invasion, serum tumor markers of CEA and CA125 (P>0.05). With respect to ultrasonography features, HCC patients had a higher proportion than ICC patients in splenomegaly (p=0.001), while ICC patients had a higher proportion than HCC patients in absence/not rich vascularity and intrahepatic bile duct dilatation (p<0.05). With respect to CT features, HCC patients were significantly different from ICC patients in the three-phase enhanced CT value mean, enhanced intensity and homogeneity of nodules (P<0.05). A multivariate logistic regression analysis was performed to further clarify the correlation of these indices. However, only age≤60 years (OR=1.861, P=0.045), male (OR=3.850, P<0.001), AFP>7ng/ml (OR=0.119, P<0.001), lymph node infiltration (OR=5.968, P<0.001), intrahepatic bile duct dilatation (OR=2.414, P=0.04), splenomegaly (OR=0.081, P<0.001), rim APHE (OR=3.109, P=0.002), and iso- or hyper enhancement (OR=0.188, P<0.001) were independent risk factors. Conclusions: While there are overlapping ultrasonography and CT features between HCC and ICC, the integration of tumor markers and specific imaging characteristics can be beneficial in distinguishing between the two.

A Retrospective Study on the Clinical Characteristics and Computed Tomography, Biochemical, and Blood Parameters of Duodenal Papillary Diseases.

This study was conducted to investigate the imaging information, laboratory data, and clinical characteristics of duodenal papillary malignancies, aiming to contribute to the early diagnosis of these diseases. The clinical characteristics, laboratory data, and computed tomography (CT) findings of 17 patients with adenoma of the major duodenal papilla (the adenoma group) and 58 patients with cancer of the major duodenal papilla (the cancer group) were retrospectively analyzed. The measurement data were analyzed using t test and expressed as mean ± standard deviation. The counting data were analyzed using the χ2 test and expressed in n (%). Pearson correlation analysis was also conducted, and a scatter plot was drawn. There were significant differences in the diameter, shape, margin, and target sign of the major duodenal papilla, pancreatic duct diameter, common bile duct diameter, enhancement uniformity, fever, direct bilirubin, total bilirubin, carcinoembryonic antigen, carbohydrate antigen 19-9, and jaundice between the adenoma group and the cancer group (P < .01). The enhancement magnitude of the duodenal papilla was correlated with the lesion size, and the venous phase CT value of the enhanced scan was correlated with the duodenal papilla diameter (P < .05). Additionally, 12 patients in the cancer group suffered from malignant transformation of adenomas. Firstly, CT is of high value in the diagnosis of duodenal papilla diseases. Secondly, the enhancement magnitude of the duodenal papilla is correlated with the lesion size. Thirdly, patients with duodenal papilla adenomas have a risk of progression into adenocarcinoma, thereby requiring close follow-up.

Non-invasive fast assessment of hepatic injury through computed tomography imaging with renal-clearable Bi-DTPA dimeglumine.

Enhanced computed tomography (CT) imaging with iodinated imaging probes is widely utilized for the diagnosis and evaluation of various liver diseases. However, these iodine-based imaging probes face intractable limitations including allergic reactions and contraindications. Herein, we propose the utilization of renal-clearable iodine-free bismuth chelate (Bi-DTPA dimeglumine) for the non-invasive fast assessment of hepatic ischemia-reperfusion injury (HIRI) via CT imaging for the first time. Bi-DTPA dimeglumine offers several advantages such as simple synthesis, no purification requirement, a yield approaching 100%, large-scale production capability (laboratory synthesis > 100 g), excellent biocompatibility and superior CT imaging performance. In a normal rat model, the administration of Bi-DTPA dimeglumine resulted in a significant 63.79% increase in liver CT value within a very short time period (30 s). Furthermore, in a HIRI rat model, Bi-DTPA dimeglumine enabled the rapid differentiation between healthy and injured areas based on the notable disparity in liver CT values as early as 15 min post-reperfusion, which showed a strong correlation with the histopathological analysis results. Additionally, Bi-DTPA dimeglumine can be almost eliminated from the body via the kidneys within 24 h. As an inherently advantageous alternative to iodinated imaging probes, Bi-DTPA dimeglumine exhibits promising prospects for application in liver disease diagnosis.

Influence of splenomegaly on aortic and liver parenchymal CT numbers during contrast-enhance CT in patients with cirrhosis

IntroductionTo compare CT (computed tomography) values for enhancement of the abdominal aorta and liver parenchyma during dynamic contrast enhancement (CE) CT in cirrhotic patients with and without splenomegaly (SM). MethodsWe considered 258 patients (83 males and 46 females for the splenomegaly group, and 83 males and 46 females for the control group) for this retrospective study. We measured CT values in the abdominal aorta and hepatic parenchyma during the hepatic arterial (HAP) and portal venous (PVP) phases. The aortic CE at HAP and the hepatic parenchymal CE at PVP were compared between the two groups. For success rate of scans, we also calculated the optimal CE rates (>280 HU in the abdominal aorta and >50 HU in the hepatic parenchyma) for each group. ResultsIn the SM group, the CE for abdominal aorta was decreased during the aortic phase for a dynamic CE-CT (p < 0.05). When evaluating the success rates, they were found to be 65.1 % and 58.9 % in the SM group and 81.4 % and 72.3 % in the non-SM group (p < 0.05). ConclusionThe success rate of scans and CE for the abdominal aorta during the aortic phase exhibited a significant decrease during dynamic CE-CT scans on patients with SM. Patients with SM may have reduced diagnostic ability with typical contrast injection protocols. Implications for practiceIt may be necessary to change the injection rates and contrast medium volume during CE-CT depending on the presence or absence of SM.

Predicting subsolid pulmonary nodules before percutaneous needle biopsy: a comparison of artificial neural network and biopsy results

To establish an artificial neural network (ANN) model to predict subsolid nodules (SSNs) before percutaneous core-needle biopsy (PCNB). The results of the two methods were compared to provide guidance on the treatment of SSNs. This was a single-centre retrospective study using data from 1,459 SSNs between 2013 and 2021. The ANN was developed using data from patients who underwent surgery following computed tomography (CT) (SFC) and validated using data from patients who underwent surgery following biopsy (SFB). The prediction results of the ANN for the PCNB group and the histopathological results obtained after biopsy were compared with the histopathological results of lung nodules in the same group after surgery. Additionally, the choice of predictors for PCNB was analysed using multivariate analysis. There was no significant difference between the accuracies of the ANN and PCNB in the SFB group (p=0.086). The sensitivity of PCNB was lower than that of the ANN (p=0.000), but the specificity was higher (p=0.001). PCNB had better diagnostic ability than the ANN. The incidence of precursor lesions and non-neoplastic lesions in the SFB group was lower than that in the SFC group (p=0.000). A history of malignant tumours, size (2-3 cm), volume (>400 cm3) and mean CT value (≥-450 HU) are important factors for selecting PCNB. Both ANN and PCNB have comparable accuracy in diagnosing SSNs; however, PCNB has a slightly higher diagnostic ability than ANN. Selecting appropriate patients for PCNB is important for maximising the benefit to SSN patients.

Femoroacetabular Impingement Measurements Obtained From Two-Dimensional Radiographs Versus Three-Dimensional–Reconstructed Computed Tomography Images Result in Different Values

To compare the reliability and accuracy of radiographic measurements obtained from 2-dimensional (2D) radiographs and 3-dimensional (3D)-reconstructed computed tomography (CT) images in the assessment of femoroacetabular impingement syndrome (FAIS). Consecutive patients with FAIS from January 2018 to December 2020 were identified and included in this study. Two fellowship-trained surgeons and 2 fellows performed blinded radiographic measurements. Lateral center-edge angle (LCEA) and Tönnis angles were measured on anteroposterior pelvic radiographs, and alpha angles were measured on frog lateral radiographs. Reliability coefficients for individual measurement accuracy were performed using the Cronbach alpha and intra- and inter-rater intraclass correlation coefficients (ICCs). Composite measurements for LCEA, Tönnis angle, and alpha angle were compared with the corresponding 3D value using paired sample t-tests. Fifty-three patients with FAIS with standardized 2D radiographic and 3D-reconstructed CT imaging were included. All reliability metrics met thresholds for internal reliability. Inter-rater ICCs for LCEA, Tönnis angle, and alpha angle were (0.928, 0.888, 0.857, all P < .001). When we compared 2D radiographic measurements with 3D-reconstructed CT values, there was a significant difference in the LCEA for 2 authors: surgeon 1 (mean [M]= -9.14, standard deviation [SD]= 5.7); t(52)= -11.6, P < .001, and surgeon 2 (M= -5.9°, SD= 4.7); t(52)= -9.2, P < .001. Significant differences were seen for Tönnis angle for 2 authors: fellow 2 (M= 3.9°, SD= 5.6); t(52)= 5.1, P < .001, and surgeon 2 (M= -2.6°, SD= 4.1); t(52)= -4.6, P < .001. Alpha angle measurements compared to the 3D-reconstructed alpha angle at 2 o'clock was significantly different for 3 authors: fellow 1 (M= 11.9°, SD= 16.2); t(52)= 5.3, P < .001; fellow 2 (M= 10.4°, SD= 18.6); t(52)= 4.1, P= .002; and surgeon 2 (M= -6.5°, SD= 16.2); t(52)= -2.9, P= .005. Positive mean values indicate 2D radiographic measurements overestimated 3D reconstruction values and negative mean values indicate underestimation. The use of 2D radiographs alone for preoperative planning of FAIS may lead to inaccuracies in radiographic measurements. Level, III retrospective cohort study.

Predicting the pathological invasiveness in patients with a solitary pulmonary nodule via Shapley additive explanations interpretation of a tree-based machine learning radiomics model: a multicenter study.

Radiomics models could help assess the benign and malignant invasiveness and prognosis of pulmonary nodules. However, the lack of interpretability limits application of these models. We thus aimed to construct and validate an interpretable and generalized computed tomography (CT) radiomics model to evaluate the pathological invasiveness in patients with a solitary pulmonary nodule in order to improve the management of these patients. We retrospectively enrolled 248 patients with CT-diagnosed solitary pulmonary nodules. Radiomic features were extracted from nodular region and perinodular regions of 3 and 5 mm. After coarse-to-fine feature selection, the radiomics score (radscore) was calculated using the least absolute shrinkage and selection operator logistic method. Univariate and multivariate logistic regression analyses were performed to determine the invasiveness-related clinicoradiological factors. The clinical-radiomics model was then constructed using the logistic and extreme gradient boosting (XGBoost) algorithms. The Shapley additive explanations (SHAP) method was then used to explain the contributions of the features. After removing batch effects with the ComBat algorithm, we assessed the generalization of the explainable clinical-radiomics model in two independent external validation cohorts (n=147 and n=149). The clinical-radiomic XGBoost model integrating the radscore, CT value, nodule length, and crescent sign demonstrated better predictive performance than did the clinical-radiomics logistic model in assessing pulmonary nodule invasiveness, with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.889 [95% confidence interval (CI), 0.848-0.927] in the training cohort. The SHAP algorithm illustrates the contribution of each feature in the final model. The specific model decision process was visualized using a tree-based decision heatmap. Satisfactory generalization performance was shown with AUCs of 0.889 (95% CI, 0.823-0.942) and 0.915 (95% CI, 0.851-0.963) in the two external validation cohorts. An interpretable and generalized clinical-radiomics model for predicting pulmonary nodule invasibility was constructed to help clinicians determine the invasiveness of pulmonary nodules and devise assessment strategies in an easily understandable manner.

Feasibility study of using low-kilovoltage, prospective gating, high-pitch, dual-source computed tomography prior to transcatheter aortic valve replacement: analysis of image quality and radiation dose.

Computed tomography (CT) scans before transcatheter aortic valve replacement (TAVR) are used to evaluate the aortic valve and guide the selection of appropriate valve stents. Accurate imaging evaluation can ensure the success rate of surgery while reducing the incidence of complications. Multiple studies have adopted a protocol of coronary artery, aortic valve, and total aortic scan, with the patients receiving higher radiation doses. The aim of this study was to evaluate the image quality, radiation dose, and diagnostic performance of dual-source computed tomography (DSCT) with high-pitch spiral scanning for TAVR. A total of 240 patients being evaluated for TAVR were continuously enrolled. Based on the differences in electrocardiography (ECG) gating and tube voltage, the patients were divided into 4 groups: group A, 70-kV prospective ECG gating, high-pitch helical; group B, 70-kV retrospective ECG gating; group C, 100-kV prospective ECG gating, high-pitch helical; and group D, 120-kV prospective ECG gating, high-pitch helical. Image quality was evaluated on a 4-point scale. The image signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for objective evaluation. The radiation doses of all patients were recorded. The image quality and radiation dose of each group were compared. There were no differences in age, body mass index (BMI), subjective image quality scores, CT values between the aorta and the coronary artery, or image CNR between the 4 groups. The mean radiation doses of groups A-D were 4.13±0.69, 4.79±0.58, 12.00±1.62, and 15.01±1.90 mSv, respectively. The mean radiation dose in group A (70-kV prospective ECG gating) decreased significantly (P<0.05). Using low-kilovoltage, high-pitch DSCT can provide comparable image quality for TAVR evaluation and significantly reduce the radiation dose.

Clinical Application of Dark-blood Imaging in Head and Neck CT Angiography: Effect on Image Quality and Plaque Visibility

The aim of this study was to explore the potential of a newly developed dark-blood imaging technique to improve image quality and plaque visibility in head and neck computed tomography (CT) angiography. Patients who underwent triphasic head and neck CT angiography scans from August 2021 to March 2023 were retrospectively enrolled (mean age 67.23±10.81 [SD] years, range 43-85 years, 64.7% male). The CT protocol consists of pre-contrast, arterial and delayed phases. Dark-blood images were postprocessed with the contrast-enhancement boost (CE-boost) technique. The quantitative assessment involved evaluating the CT value, image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of calcified plaque and non-calcified plaque. The plaque CNR relative to the vessel lumen (CNRplaque-lumen), vessel wall (CNRplaque-wall), and adjacent muscle (CNRplaque-muscle) was respectively calculated. Two experienced radiologists independently evaluated the CT images (5, best; 1, worst) by four characteristics including calcified plaque visibility, non-calcified plaque visibility, diagnostic confidence, and overall image quality. Inter-rater variability was also evaluated. The artery stenosis rate and plaque burden on dark-blood images were measured and compared with arterial phases. The intraclass correlation coefficient (ICC) was used for consistency analysis. The diagnostic accuracy of dark-blood images for the stenosis rate was evaluated by the area under the curve (AUC). A total of 43 patients with 54 calcified plaques and 34 non-calcified plaques were assessed in this study. When compared with pre-contrast and delayed phase, dark-blood images yielded significantly higher CNRplaque-lumen and CNRplaque-muscle of calcified (219.79±159.20 and 181.23±112.12, respectively) and non-calcified (30.30±29.11 and 6.28±4.75, respectively) plaques (all p<0.001). Calcified plaque SNR of dark-blood showed equal or slightly lower than other phases (p>0.05 or p=0.02). A major increase was observed in the non-calcified plaque SNR of dark-blood compared to the arterial phase (5.56±3.71 vs. 4.23±3.56, p=0.02), although there were no apparent differences compared to pre-contrast and delayed phases (p>0.05). In subjective analyzes, the calcified plaque visibility (4.99±0.07), non-calcified plaque visibility (4.62±0.48), overall image quality (4.81±0.34), and diagnostic confidence (4.74±0.36) in dark-blood images dominated the highest scores (p<0.001). The subjective scores of radiologists exhibited good consistency (all kappa value>0.7). The dark-blood image and the arterial phase image exhibited good consistency in identifying the stenosis rate (p<0.001). In the evaluation of plaque burden, the interobserver agreement for dark-blood images was higher compared to arterial phase images (ICC = 0.870 vs. 0.729). Compared to conventional triphasic head and neck CT angiography, the CE-boost derived dark-blood imaging demonstrated a significant improvement in image quality and visibility for both calcified and non-calcified plaque assessment.

A comparison of image quality of cerium oxide nanoparticles and iodine contrast agents in computed tomography scan

Computed tomography (CT) scan, with iodine-based contrast, produces good image quality by improving the visualisation of relatively low-contrast internal body structures. However, the impact of using iodinated difference should be considered in patients susceptible to contrast allergy and renal impairment. Therefore, alternative contrast materials, such as cerium oxide nanoparticles (CeO2 NPs), must be used, with biocompatible properties and strong X-ray attenuation capabilities. This study compared the CT scan image quality of CeO2 NPs and iodinated contrast agents. This experimental study started by preparing a suspension of CeO2 NPs and iodine in aquabidest at a concentration of 500 ppm. The suspension was scanned using a CT scan with a helical scanning method. The exposure coefficient parameters were set for the tube voltage of 80 kV, Field of View of 28 cm, slice thickness of 5 mm, and tube current time of 150 mAs, 200 mAs, and 250 mAs. Then, CT images in DICOM data format were processed using MicroDICOM Viewer software. The quality of the CT scan images was analysed based on the CT number value, noise level, and contrast resolution. The images of CeO2 nanoparticles have higher CT values, lower noise levels, and better contrast resolution than those of iodine contrast agents. The results show that the CT image results of CeO2 NPs have better quality than those of iodine-containing contrast agents.

Quantitative CT parameters combined with preoperative systemic inflammatory markers for differentiating risk subgroups of thymic epithelial tumors

BackgroundThymic epithelial tumors (TETs) are the most common primary neoplasms of the anterior mediastinum. Different risk subgroups of TETs have different prognosis and therapeutic strategies, therefore, preoperative identification of different risk subgroups is of high clinical significance. This study aims to explore the diagnostic efficiency of quantitative computed tomography (CT) parameters combined with preoperative systemic inflammatory markers in differentiating low-risk thymic epithelial tumors (LTETs) from high-risk thymic epithelial tumors (HTETs).Methods74 Asian patients with TETs confirmed by biopsy or postoperative pathology between January 2013 and October 2022 were collected retrospectively and divided into two risk subgroups: LTET group (type A, AB and B1 thymomas) and HTET group (type B2, B3 thymomas and thymic carcinoma). Statistical analysis were performed between the two groups in terms of quantitative CT parameters and preoperative systemic inflammatory markers. Multivariate logistic regression analysis was used to determine the independent predictors of risk subgroups of TETs. The area under curve (AUC) and optimal cut-off values were calculated by receiver operating characteristic (ROC) curves.Results47 TETs were in LTET group, while 27 TETs were in HTET group. In addition to tumor size and CT value of the tumor on plain scan, there were statistical significance comparing in CT value of the tumor on arterial phase (CTv-AP) and venous phase (CTv-VP), and maximum enhanced CT value (CEmax) of the tumor between the two groups (for all, P < 0.05). For systemic inflammatory markers, HTET group was significantly higher than LTET group (for all, P < 0.05), including platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII). Multivariate logistic regression analysis showed that NLR (odds ratio [OR] = 2.511, 95% confidence interval [CI]: 1.322–4.772, P = 0.005), CTv-AP (OR = 0.939, 95%CI: 0.888–0.994, P = 0.031) and CTv-VP (OR = 0.923, 95%CI: 0.871–0.979, P = 0.008) were the independent predictors of risk subgroups of TETs. The AUC value of 0.887 for the combined model was significantly higher than NLR (0.698), CTv-AP (0.800) or CTv-VP (0.811) alone. The optimal cut-off values for NLR, CTv-AP and CTv-VP were 2.523, 63.44 Hounsfeld Unit (HU) and 88.29HU, respectively.ConclusionsQuantitative CT parameters and preoperative systemic inflammatory markers can differentiate LTETs from HTETs, and the combined model has the potential to improve diagnostic efficiency and to help the patient management.

Deep learning reconstruction improves the image quality of low-dose temporal bone CT with otitis media and mastoiditis patients

ObjectiveTo evaluate the image quality of low-dose temporal bone computed tomography (CT) in otitis media and mastoiditis patients by using deep learning reconstruction (DLR). Materials and methodsA total of ninety-seven temporal bones from 53 consecutive adult patients who had suspected otitis media and mastoiditis and underwent temporal bone CT were prospectively enrolled. All patients underwent high resolution CT protocol (group A) and an additional low-dose protocol (group B). In group A, high resolution data were reconstructed by filter back projection (FBP). In group B, low-dose data were reconstructed by DLR mild (B1), DLR standard (B2) and DLR strong (B3). The objective image quality was analyzed by measuring the CT value and image noise on the transverse image and calculating the signal-to-noise ratio (SNR) on incudomallear joint, retroauricular muscle, vestibule and subcutaneous fat. Subjective image quality was analyzed by using a five-point scale to evaluate nine anatomical structures of middle and inner ear. The number of temporal bone lesions which involved in five structures of middle ear were assessed in group A, B1, B2 and B3 images. ResultsThere were no significant differences in the CT values of the four reconstruction methods at four structures (all p > 0.05). The DLR group B1, B2 and B3 had significantly less image noise and a significantly higher SNR than group A at four structures (all p < 0.001). The group B1 had comparable subjective image quality as group A in nine structures (all p > 0.05), however, the group B3 had lower subjective image quality than group A in modiolus, spiral osseous lamina and stapes (all p < 0.001), the group B2 had lower subjective image quality than group A in modiolus and spiral osseous lamina (both p < 0.05). The number of temporal bone lesions which involved in five structures for group A, B1 and B2 images were no significant difference (all p > 0.05), however, the number of temporal bone lesions which involved in mastoid for group B3 images were significantly more than group A (p < 0.05). The radiation dose of high resolution CT protocol and low-dose protocol were 0.55 mSv and 0.11 mSv, respectively. ConclusionCompared with high resolution CT protocol, in the low-dose protocol of temporal bone CT, DLR mild and standard could improve the objective image quality, maintain good subjective image quality and satisfy clinical diagnosis of otitis media and mastoiditis patients.

The cross-sectional area of erector spinae muscle and the liver-to-spleen ratio are associated with frailty in older patients with diabetes: a cross-sectional study

BackgroundOlder patients with diabetes mellitus are more susceptible to frailty. Although some imaging markers of appendicular skeletal muscle mass obtained using dual-energy X-ray absorptiometry or computed tomography (CT) imaging can reflect frailty status, the association between imaging indices obtained by abdominal CT scans and frailty in older inpatients has not been reported.MethodsA total of 151 older inpatients with diabetes mellitus (median age, 79 years; men, 42%) who underwent abdominal CT scans close to the admission date were studied to examine the associations between abdominal CT indices and frailty. Two frailty definitions were used: the modified Cardiovascular Health Study (mCHS) criteria and Kihon Checklist (KCL) criteria. Using the imaging analysis software SYNAPSE VINCENT®, we compared the cross-sectional areas (CSA) of four truncal muscles (erector spinae, iliopsoas, rectus abdominis, and abdominal oblique muscles) and the liver-to-spleen ratio (L/S), the ratio of the CT values of the liver and spleen between frail and non-frail patients. The muscle areas that showed the strongest associations with frailty were also investigated in relation to grip strength and walking speed. Finally, multivariate binominal logistic regression analyses were performed to assess the independent associations of CSA of muscle and L/S with the prevalence of frailty.ResultsThe prevalence of frailty defined by the mCHS and KCL criteria was 55% and 52%, respectively. The CSA of the erector spinae muscle was most significantly associated with frailty, and was significantly smaller in both sexes of mCHS-defined frail patients and in men with KCL-defined frailty. The CSA of erector spinae muscle was also positively correlated with grip strength and walking speed. In contrast, the L/S was higher in men with KCL-defined frailty. Multivariate logistic regression analyses revealed that the CSA of the erector spinae muscle was independently associated with mCHS-defined frailty in women, and the L/S was associated with KCL-defined frailty in men.ConclusionsThe CSA of erector spinae muscle and low liver fat content could be indices of frailty in older patients with diabetes.

Reference Range of CT Value in NC-CBBCT Based on Female Breast Structure.

As a new high-resolution three-dimensional CT imaging technology, the essential reference range of CT values in Cone-beam breast computed tomography (CBBCT) has not been established to date. To determine the reference range of computed tomography (CT) values in CBBCT for clinical breast examination. In total, 913 cases (1167 lateral) were subject to CBBCT. CT values of the glandular tissue, fat and different quadrants and different distances of CBBCT images were analyzed. The nipple and muscle were also evaluated. A total of 672 lateral breasts were included in the normal group for investigation. The reference range of the absolute CT value of the chest wall muscle is -136.68~43.36 HU. The reference range of the absolute CT value of the nipple is 176.39~334.02 HU. The reference range of the absolute CT value of fat is -190.4~-63.67HU, and of glandular tissue is -12.2~199.07HU. Our results firstly established the baseline CT values of Non-contrast CBBCT in female breasts, which will benefit cancer screening and lesion locating. The closer the normal breast fat and glandular tissue is to the nipple, the greater the CT value. The older the age, the lower the density. The CT values of fat are unstable in a distance of less than 5 cm, and the CT values of glandular tissues are relatively stable. The difference between the upper and lower quadrants is significant in the same lateral breast and the same section.