CT Scan Parameters Research Articles

The study of plain CT combined with contrast-enhanced CT-based models in predicting malignancy of solitary solid pulmonary nodules

To compare the diagnostic performance between plain CT-based model and plain plus contrast CT-based modelin the classification of malignancy for solitary solid pulmonary nodules. Between January 2012 and July 2021, 527 patients with pathologically confirmed solitary solid pulmonary nodules were collected at dual centers with similar CT examinations and scanning parameters. Before surgery, all patients underwent both plain and contrast-enhanced chest CT scans. Two clinical characteristics, fifteen plain CT characteristics, and four enhanced characteristics were used to develop two logistic regression models: model 1 (plain CT only) and model 2 (plain + contrast CT). The diagnostic performance of the two models was assessed separately in the development and external validation cohorts using the AUC. 392 patients from Center A were included in the training cohort (median size, 20.0 [IQR, 15.0–24.0] mm; mean age, 55.8 [SD, 9.9] years; male, 53.3%). 135 patients from Center B were included in the external validation cohort (median size, 20.0 [IQR, 16.0–24.0] mm; mean age, 56.4 [SD, 9.6] years; male, 51.9%). Preoperative patients with 201 malignant (adenocarcinoma, 148 [73.6%]; squamous cell carcinoma, 35 [17.4%]; large cell carcinoma,18 [9.0%]) and 326 benign (pulmonary hamartoma, 118 [36.2%]; sclerosing pneumocytoma, 35 [10.7%]; tuberculosis, 104 [31.9%]; inflammatory pseudonodule, 69 [21.2%]) solitary solid pulmonary nodules were gathered from two independent centers. The mean sensitivity, specificity, accuracy, PPV, NPV, and AUC (95%CI) of model 1 (Plain CT only) were 0.79, 0.78, 0.79, 0.67, 0.87, and 0.88 (95%CI, 0.82–0.93), the model 2 (Plain + Contrast CT) were 0.88, 0.91, 0.90, 0.84, 0.93, 0.93 (95%CI, 0.88–0.98) in external validation cohort, respectively. A logistic regression model based on plain and contrast-enhanced CT characteristics showed exceptional performance in the evaluation of malignancy for solitary solid lung nodules. Utilizing this contrast-enhanced CT model would provide recommendations concerning follow-up or surgical intervention for preoperative patients presenting with solid lung nodules.

Early Challenges in the Implementation of Automated CranialRebuild Freeware for Generation of Patient-Specific Cranial Implant Using Additive Manufacturing: A Pilot Project in Review.

Traumatic Brain Injury (TBI) is a significant global health concern, particularly in low- and middle-income countries (LMICs) where access to medical resources is limited. Decompressive craniectomy (DHC) is a common procedure to alleviate elevated intracranial pressure (ICP) following TBI, but the cost of subsequent cranioplasty can be prohibitive, especially in resource-constrained settings. We describe challenges encountered during the beta-testing phase of CranialRebuild 1.0, an automated software program tasked with creating patient-specific cranial implants (PSCIs) from CT images. Two pilot clinical teams in the Philippines and Ukraine tested the software, providing feedback on its functionality and challenges encountered. The constructive feedback from the Philippine and Ukrainian teams highlighted challenges related to CT scan parameters, DICOM file arrays, software limitations, and the need for further software improvements. CranialRebuild 1.0 shows promise in addressing the need for affordable PSCIs in LMICs. Challenges and improvement suggestions identified throughout the beta-testing phase will shape the development of CranialRebuild 2.0, with the aim of enhancing its functionality and usability. Further research is needed to validate the software's efficacy in a clinical setting and assess its cost-effectiveness.

COPD Subtypes Are Differentially Associated With Cardiovascular Events and COPD Exacerbations

The coronary artery calcium score (CACS) and ratio of the pulmonary artery to aorta diameters (PA:A ratio) measured from chest CT scans have been established as predictors of cardiovascular events and COPD exacerbations, respectively. However, little is known about the reciprocal relationship between these predictors and outcomes. Furthermore, the prognostic implications of COPD subtypes on clinical outcomes remain insufficiently characterized. How can these two chest CT scan-derived parameters predict subsequent cardiovascular events and COPD exacerbations in different COPD subtypes? Using COPDGene study data, we assessed prospective cardiovascular disease (CVD) and COPD exacerbation risk in patients with COPD (Global Initiative for Chronic Obstructive Lung Disease spirometric grades 2-4), focusing on CACS and PA:A ratio at study enrollment, with logistic regression models. These outcomes were analyzed in three COPD subtypes: 1,042 patients with non-emphysema-predominant disease (NEPD) (low attenuation area at-950 Hounsfield units [LAA-950]< 5%), 1,324 patients with emphysema-predominant disease (EPD) (LAA-950≥ 10%), and 465 patients with intermediate emphysema disease (5%≤ LAA-950< 10%). Our study indicated significantly higher overall risk for cardiovascular events in patients with higher CACS (≥ median; OR, 1.61; 95%CI, 1.30-2.00) and increased COPD exacerbations in those with higher PA:A ratios (≥ 1; OR, 1.80; 95%CI, 1.46-2.23). Notably, patients with NEPD showed a stronger association between these indicators and clinical events than those with EPD (with CACS/CVD, NEPD vsEPD: OR, 2.02 vs1.41; with PA:A ratio/COPD exacerbation, NEPD vsEPD: OR, 2.50 vs1.65); the difference in ORs between COPD subtypes was statistically significant for CACS/CVD. Two chest CT scan parameters, CACS and PA:A ratio, hold distinct predictive values for cardiovascular events and COPD exacerbations that are influenced by specific COPD subtypes. ClinicalTrials.gov; No.: NCT00608764; URL: www. gov.

Impact of Vaccination Status on Chest CT Findings and Disease Outcomes in COVID-19 Era: A Retrospective Study

Background: Computerized Tomography (CT) was extensively used in the COVID-19 era to confirm the diagnosis and follow the patient's response. The vaccine was rapidly introduced to break the disease chain of infection. The current study primarily aimed to examine the relationship between vaccination status and pulmonary CT findings. Moreover, it also aimed to validate the role of CT scan along with other patient criteria in predicting disease outcomes. Methods: A retrospective cohort study was conducted at the radiology department of two Iraqi hospitals in Baghdad. The study enrolled all hospitalized patients with a confirmed COVID-19 diagnosis older than 18 years old. Their data regarding demographic criteria, vaccination criteria (the status and types), and radiological CT-scan parameters (including CT finding and severity score index) were collected Results: It was found that 23 percent of COVID-19 patients were immunized. Most of the unvaccinated cases were older than 45 years and were females. There was a significant correlation between the degree and severity of lung involvement and the vaccination status (p &lt; 0.001). The worst radiological sign for severity was the ground glass appearance. The vaccine type showed significant changes in chest CT. Pfizer had the worst severity score, followed by Sinopharm in vaccinated cases. The overall mortality was 4.5%. Moreover, the vaccine significantly reduced mortality among vaccinated vs. non-vaccinated cases (p = 0.03). By logistic regression, the CT score reliably predicted mortality with an odds ratio of 1.31 (1.18 to 1.45; p &lt; 0.001). Conclusion: Vaccines were found to be significantly effective in protecting vaccinated people against severe infection and limiting lung injury, as evidenced by CT scores. Vaccines had a trend effect on reducing mortality. Moreover, CT scores were reliable in predicting the disease outcome.

CT Imaging Assessment of Response to Treatment in Allergic Bronchopulmonary Aspergillosis in Adults With Bronchial Asthma

BackgroundOne of the major challenges in managing allergic bronchopulmonary aspergillosis (ABPA) remains consistent and reproducible assessment of response to treatment. Research questionWhat are the most relevant changes in computed tomography (CT-scan) parameters over time for assessing response to treatment? Study Design and MethodsIn this ancillary study of a randomized clinical trial (NEBULAMB), asthmatic patients with available CT-scan and without exacerbation during a 4-month ABPA exacerbation treatment period (corticosteroids and itraconazole) were included. Changed CT-scan parameters were assessed by systematic analyses of CT-scan findings at initiation (M0) and end of treatment (M4). CT-scans were assessed by two radiologists blinded to the clinical data. Radiological parameters were determined by selecting those showing significant changes over time. Improvement of at least one, without worsening of the others, defined the radiological response. Agreement between radiological changes, clinical and immunologic responses was likewise investigated. ResultsAmong the 139 originally randomized patients, 132 were included. We identified 5 CT-scan parameters showing significant changes at M4: mucoid impaction extent, mucoid impaction density, centrilobular micronodules, consolidation/ground-glass opacities and bronchial wall thickening (P<0.05). These changes were only weakly associated with one another, except for mucoid impaction extent and density. No agreement was observed between clinical or immunologic and radiological responses, assessed as an overall response, or considering each of the parameters (Cohen’s κ, -0.01 to 0.24). InterpretationChanges in extent and density of mucoid impactions, centrilobular micronodules, consolidation/ground-glass opacities and thickening of the bronchial walls were found to be the most relevant CT-scan parameters to assess radiological response to treatment. A clinical, immunologic and radiological multidimensional approach should be adopted to assess outcomes, probably with a composite definition of response to treatment.

A Vision for Global CT Radiation Dose Optimization

The topic of CT radiation dose management is receiving renewed attention since the recent approval by CMS for new CT dose measures. Widespread variation in CT dose persists in practices across the world, suggesting that current dose optimization techniques are lacking. The author outlines a proposed strategy for facilitating global CT radiation dose optimization. CT radiation dose optimization can be defined as the routine use of CT scan parameters that consistently produce images just above the minimum threshold of acceptable image quality for a given clinical indication, accounting for relevant patient characteristics, using the most dose-efficient techniques available on the scanner. To accomplish this, an image quality–based target dose must be established for every protocol; for nonhead CT applications, these target dose values must be expressed as a function of patient size. As variation in outcomes is reduced, the dose targets can be decreased to more closely approximate the minimum image quality threshold. Maintaining CT radiation dose optimization requires a process control program, including measurement, evaluation, feedback, and control. This is best accomplished by local teams made up of radiologists, medical physicists, and technologists, supported with protected time and needed tools, including analytics and protocol management applications. Other stakeholders critical to facilitating CT radiation dose management include researchers, funding agencies, industry, regulators, accreditors, payers, and the ACR. Analogous coordinated approaches have transformed quality in other industries and can be the mechanism for achieving the universal goal of CT radiation dose optimization.

Assessment of radiographers' knowledge about radiation doses and DRLs in computed tomography departments in Jeddah, Saudi Arabia: A cross-sectional study

ObjectiveTo assess radiographers' understanding of radiation safety considering the newly approved national diagnostic reference levels (DRLs) as an optimization tool for radiation dose. MethodsA cross-sectional study was conducted in Saudi Arabia among radiographers working at local hospitals in Jeddah city from February to March 2022. The survey comprised of 22 questions involving demographic information; and general information related to radiation dose; CTDIvol and DRLs. Data were analyzed using IBM SPSS Statistics version 26. Chi-square test was used to compare demographic groups regarding their distribution of responses with 0.05 as the level of significance. ResultsA total of 169 radiographers participated in the study (39 % females, 60 % males). Most of the participants (91 %) were aware of the description of the ALARA principle. It was noted that (47 %) of the participants indicated that the routine scanning protocols are designed by the radiologists. The majority of them (78 %) were confident to manipulate the CT scanning parameters properly. In addition, half of the participants (53 %) were aware of the CTDIvol and DLP. Unexpectedly, none of the demographic variables were significantly associated with the radiographers’ knowledge about radiation dose, p-values are > 0.05. ConclusionAlthough radiographers demonstrated good knowledge of radiation protection, limited awareness of DRLs was noted among radiographers and lack of implementing and optimizing the local dose of the DRLs in this study. Therefore, education and training for healthcare professionals including radiographers are necessary to enhance clinical practical performance in radiology departments.

Pivots coniques en arthroplastie totale de hanche chez la hanche dysplasique : une étude longitudinale

IntroductionConical tapered stems may be useful implants to manage the reconstruction of complex dysplastic anatomies. The aims of this paper were to assess: the preoperative CT features of the dysplastic femurs, survival rates, complications and reasons for revision, the clinical outcomes and the radiographic outcomes of single-taper conical stems in dysplasia (defined as center edge angle <20°) at a long-term follow-up. HypothesisMonoblock conical stem provides a 10-year survival rate of at least 95%, with excellent clinical outcomes and bony ingrowth. Materials and methodsIn total 100, THAs in 85 patients (15 bilateral cases) were enrolled. The average age of the patients at surgery was 50.9±11.5 years. Assessment of the native femoral morphology was performed using CT scan, coronal (neck-shaftangle, offset, center of rotation position) and axial parameters (anteversion, mediolateral and anteroposterior femoral diameters). Clinical (HHS score) and radiological (osseointegration, subsidence and offset reconstruction) outcomes were evaluated at the last available follow-up. ResultsThe mean follow-up was 9.34±5.61 years. Severely distorted anatomies from Crowe I to Crowe IV were included, with a mean canal flare of 4.3 and a mean femoral antetorsion of 34°. The survival rates were stable at long-term (98.9% at 10 and 15 years): no aseptic loosening occurred. The mean postoperative HHS was 89.8±6.8 points. Ninety-nine percent of the stems showed bone ingrowth, from 6 months to the last available follow-up. Subsidence occurred in 18% of the cases (mean value: 2.5mm, range: 1–6mm) in the first month, with subsequent stabilization. A mild proximal stress shielding occurred in 28% of the THAs. Radiolucent lines were detected in the 8% of the cases. There was a postoperative loss of offset in 12% of the cases. DiscussionConical stems in dysplastic hips achieved bony ingrowth at long-term outcome, even in complex anatomies. Subsidence, proximal stress shielding and imperfect offset restoration may occur with this implant. Level of evidenceIV; retrospective study.

Interstitial lung disease (ILD) after COVID-19: a new fibro-inflammatory disease?

Introduction. Nowadays post-COVID respiratory symptoms that could be associated with pulmonary fibrosis progression are of concern. Objective. To compare CT and SPECT data of patients with post-COVID pulmonary fibrosis, and to define whether the lung fibrosis progression could be predictable. Material and Methods. Changes in chest CT scan, microcirculation disorders (SPECT) and impaired lung function parameters (DLCO) were analyzed in 74 post-COVID patients with residual consequences of COVID-19. Results. A year or more after the disease, 17 % of patients had isolated ground-glass areas, 24 % of patients had ventilation mosaics and air traps, most patients had compaction of the interlobular interstitial tissue of a short UIP type (67 %); consolidation zones (38 %); zones of pulmonary fibrosis of different lengths (57 %); discoid atelectasis (39 %); bronchiectasis (26 %), pulmonary hypertension (PH) (36 %). Significant decrease of the diffusion capacity and great microcirculation disorders accompanied by more than 50 % perfusion lack were detected. We demonstrated that significant radiological and functional effects of viral pneumonia were likely to be associated with post-viral interstitial lung disease. Conclusions. 1. Complete X-ray examination with lung diffusion capacity determination can contribute to optimal dispensary observation of post-COVID patients. 2. Microcirculation disorder greater than 50 % of the norm is a predictor of the lung parenchyma changes and can contribute to the prediction of long-term effects of the disease. 3. Complete radiation monitoring is required for patients over 60 years of age; post-COVID patients having severe form of the disease; patients having respiratory complaints for more than a year, regardless of the severity of COVID-19.

Impact of CT scan parameters on deformable image registration accuracy using deformable thorax phantom.

The purpose of this study was to evaluate the deformable image registration (DIR) accuracy using various CT scan parameters with deformable thorax phantom. Our developed deformable thorax phantom (Dephan, Chiyoda Technol Corp, Tokyo, Japan) was used. The phantom consists of a base phantom, an inner phantom, and a motor-derived piston. The base phantom is an acrylic cylinder phantom with a diameter of 180mm, which simulates the chest wall. The inner phantom consists of deformable, 20mm thick disk-shaped sponges with 48 Lucite beads and 48 nylon cross-wires which simulate the vascular and bronchial bifurcations of the lung. Peak-exhale and peak-inhale images of the deformable phantom were acquired using a CT scanner (Aquilion LB, TOSHIBA). To evaluate the impact of CT scan parameters on DIR accuracy, we used the four tube voltages (80, 100, 120, and 135kV) and six reconstruction algorithms (FC11, FC13, FC15, FC41, FC44, and FC52). Intensity-based DIR was performed between the two images using MIM Maestro (MIM software, Cleveland, USA). Fiducial markers (beads and cross-wires) based target registration error (TRE) was used for quantitative evaluation of DIR. In case with different tube voltages, the range of average TRE were 4.44-5.69mm (reconstruction algorithm: FC13). In case with different reconstruction algorithms, the range of average TRE were 4.26-4.59mm (tube voltage: 120kV). The TRE were differed by up to 3.0mm (3.96-6.96mm) depending on the combination of tube voltage and reconstruction algorithm. Our result indicated that CT scan parameters had moderate impact of TRE, especially for reconstruction algorithms for the deformable thorax phantom.

Comparative evaluation of post treatment CT scan and clinical parameters in open reduction and closed reduction treatment of condylar fractures.

Mandibular fracture is the second most common fracture of facial bone, next to nasal bone. Twenty-five to forty percent of mandibular fractures involve the condyle. In the literature, there exists no consensus "gold standard" treatment for mandibular condylar fractures, and there is a continuing debate on whether condylar fractures should undergo closed or open reduction. Twenty patients who had undergone open reduction and closed reduction treatment were included in the study. Clinically maximal interincisal opening, laterotrusive and protrusive movements, pain on mouth opening, malocclusion, chin deviation on mouth opening, facial nerve palsy, hematoma, infected implant, and bite force were evaluated after a minimum of 3 months postoperatively. Also, a postoperative CT is done to evaluate the anatomical position of fragment. On evaluation of clinical parameters, both groups had comparable results. However, none of the patients in open reduction group had deviation of mandible from midline on mouth opening. Also, better anatomical repositioning is obtained in open reduction group. The results of this study suggest that the open reduction method is a better alternative to closed reduction in treatment of mandibular condylar fractures.

Management of clinically relevant postoperative pancreatic fistula-related fluid collections after distal pancreatectomy.

Distal pancreatectomy is burdened by a high rate of clinically relevant postoperative pancreatic fistula (CR-POPF). The presence of a fistula-related abdominal collection often requires additional treatment such as antibiotics, percutaneous drainage, and endoscopic drainage thus prolonging patient recovery. Aim of this study was to describe the management of abdominal collections related to CR-POPF and identify variables associated with the need for invasive procedures. A retrospective review of clinical data for patients who underwent distal pancreatectomy between 2015 and 2020 was conducted. All postoperative CT-scan imaging performed for clinical signs related to POPF was reviewed. The main outcome of the study was the need for procedural management (percutaneous or endoscopic) of CR-POPF-related fluid collections at 90days after surgery. A multivariate regression analysis was adopted to analyze factors influencing procedural management of the collection. Five hundred sixteen patients were included in the study. Laparoscopic resection was performed in 290 patients (56%). At 90 days after surgery, CR-POPF occurred in 207 (40.1%) patients. A symptomatic collection related to fistula was observed in 130 patients (25.2%). Factors associated with fluid collections were increased body mass index (BMI) (25.5 versus 24, p = 0.001) and intraoperative blood loss (median of 250 versus 200ml, p < 0.001). Procedural management was required in 70 patients (13.6%); 52 patients required interventional radiology and 18 endoscopic drainage. At multivariate analysis, risk factors for invasive procedures were the following CT-scan parameters: fluid collection diameter greater than 5cm (OR 6.366, 95%CI 2.29-17.66, p = 0.001), presence of blood in the fluid collection (OR 10.618, 95%CI 1.94-58.09, p = 0.006), and enhancement of its walls (OR 4.073, 95%CI 1.22-13.57, p = 0.022). CR-POPF-related fluid collections affect about a quarter of patients undergoing distal pancreatectomy. CT-scan provides important information which can guide the management of the collection in a "step-up" fashion.

A Review of Radiomics in Predicting Therapeutic Response in Colorectal Liver Metastases: From Traditional to Artificial Intelligence Techniques.

An early evaluation of colorectal cancer liver metastasis (CRCLM) is crucial in determining treatment options that ultimately affect patient survival rates and outcomes. Radiomics (quantitative imaging features) have recently gained popularity in diagnostic and therapeutic strategies. Despite this, radiomics faces many challenges and limitations. This study sheds light on these limitations by reviewing the studies that used radiomics to predict therapeutic response in CRCLM. Despite radiomics’ potential to enhance clinical decision-making, it lacks standardization. According to the results of this study, the instability of radiomics quantification is caused by changes in CT scan parameters used to obtain CT scans, lesion segmentation methods used for contouring liver metastases, feature extraction methods, and dataset size used for experimentation and validation. Accordingly, the study recommends combining radiomics with deep learning to improve prediction accuracy.

Prediction of stroke reconvalescence after coronary bypass surgery indicated by CT scan parameters.

Stroke in the postoperative time course after heart surgery remains a serious risk. Cranial computer tomography (CCT) is the first line option to detect severe intracranial damage. However, only few data are available to predict neurological outcome. Using visual rating scales (VRSs), this study addresses reliability and effectivity to indicate neurological status and likelyhood of improvement. In a single-center retrospective evaluation, 3719 patients underwent coronary bypass surgery. Because of a delayed recovery phase and neurologic deficits after cardiac surgery 109 patients had a cranial CT scan in the early postoperative period. The incidence of clinically relevant findings within the imaging was rated by an experienced neuroradiologist using two VRS,that is, the age-related white matter changes (ARWMCs) and the Mendes-Ribeiro visual rating scale (MRVRS). Both are computer-assisted measurement schemes to detect stroke-related intracranial damage. Follow-up was investigated with regard to clinical outcome and patient-related risk profiles. Of 109 patients with postoperative cranial CT scans due to prolonged recovery phases or proven neurological damage 44.5% had one cerebral defect in CCT imaging scans only. The others showed multiple defects. During hospital stay,92.3% experienced neurological improvement exposing reduced ARWMC, while 7.1% had no improvement and correlating high scores. Of both scales, the ARWMC-VRS demonstrated superior accuracy and discrimination. The preoperative ejection fraction (EF), arteriosclerotic degeneration of carotid arteries, and reduced glomerular filtration ratewere found to have a high correlation (r = 0.0005) with the latter group. In-hospital mortality of this cohort was 8.18%. Both the ARWMC and MRVRS were found to be appropriate. They reliably discriminate the groups of stroke patients after coronary artery bypass grafting (CABG) in the analysis of CCT images. When applied at the onset of neurological symptoms both scales are able to predict neurological reconvalescence upon hospital dismission. The ARWMC scale appeared superior as it demonstrated better accuracy and discrimination. The use of both VRS in patients with suspected stroke after CABG surgery can give insightful information toward a progression of neurological dysfunction or postoperative improvement.

Improved visualization of the wrist at lower radiation dose with photon-counting-detector CT.

To compare the image quality of ultra-high-resolution wrist CTs acquired on photon-counting detector CT versus conventional energy-integrating-detector CT systems. Participants were scanned on a photon-counting-detector CT systemafter clinical energy-integrating detector CTs. Energy-integrating-detector CT scan parameters: comb filter-based ultra-high-resolution mode, 120kV, 250 mAs, Ur70 or Ur73 kernel, 0.4- or 0.6-mm section thickness. Photon-counting-detector CT scan parameters: non-comb-based ultra-high-resolution mode, 120kV, 120 mAs, Br84 kernel, 0.4-mm section thickness. Two musculoskeletal radiologists blinded to CT system, scored specific osseous structures using a 5-point Likert scale (1 to 5). The Wilcoxon rank-sum test was used for statistical analysis of reader scores. Paired t-test was used to compare volume CT dose index, bone CT number, and image noise between CT systems. P-value < 0.05 was considered statistically significant. Twelve wrists (mean participant age 55.3 ± 17.8, 6 females, 6 males) were included. The mean volume CT dose index was lower for photon-counting detector CT (9.6 ± 0.1mGy versus 19.0 ± 6.7mGy, p < .001). Photon-counting-detector CT images had higher Likert scores for visualization of osseous structures (median score = 4, p < 0.001). The mean bone CT number was higher in photon-counting-detector CT images (1946 ± 77 HU versus 1727 ± 49 HU, p < 0.001). Conversely, there was no difference in the mean image noise of the two CT systems (63 ± 6 HU versus 61 ± 6 HU, p = 0.13). Ultra-high-resolution imaging with photon-counting-detector CT depicted wrist structures more clearly than conventional energy-integrating-detector CT despite a 49% radiation dose reduction.

Anthropomorphic phantom organ dose assessment using optically stimulated luminescence dosimeters unified in multi-detector computed tomography

This organ dose profile investigation is based on a technology that allows for the acquisition of densely sampled dose data, obtained using modified nanoDot™ OSLDs and a typical anthropomorphic Alderson Radiation Therapy phantom (ARTM 1092 model). The CT scan parameters were based on adult chest-abdomen and head region CT procedures, which were performed using a Siemens Somatom Definition AS+ at Hospital Sultanah Aminah in Johor. In studying the scanned region, the tube voltage and exposure duration values were considerably altered, with modulation approaches significantly altering the dosage distribution. In the head-neck procedure, the average absorbed dose per slice for the brain and thyroid was 3.469–33.645 mGy and 3.372–34.528 mGy, respectively. The distribution of chest-abdomen region organ dose mapping explains that the lungs received the highest organ dose, receiving a dose of 20.795 mGy from protocol P4, a setting of 140 kV tube voltage in the CT chest-abdomen protocol. The organ dosage levels in this investigation varied from 2.277 to 20.794 mGy, depending on tube voltage, tube current, and exposure period, as well as the organ composition, location, and surrounding anatomic structures. The average absorbed dosage in the lungs per slice varied from 3.439 to 20.794 mGy. The most significant coefficient of variation (CoV) for dosage samples of the lungs inside separate slices was 13%. The radiation dose patterns are consistent with similar tests and modalities, with variations dependent on tube voltage, exposure period, tube current, slice collimation, and pitch factor. The LED and CAL measured data (Mean ± SD) were determined to be an average of 4657 ± 563 and 1677 ± 31 counts, respectively. The supplied data is evidence of the microStar reader's superior performance.

Impact of multidetector computed tomography scan parameters, novel reconstruction settings, and lung nodule characteristics on nodule diameter measurements: A phantom study.

Novel CT reconstruction techniques strive to maintain image quality and processing efficiency. The purpose of this study is to investigate the impact of a newer hybrid iterative reconstruction technique, Adaptive Statistical Iterative Reconstruction-V (ASIR-V), in combination with various CT scan parameters on the semi-automated quantification using various lung nodules. A chest phantom embedded with eight spherical objects was scanned using varying CT parameters such as tube current and ASIR-V levels. We calculated absolute percentage error (APE) and mean APE (MAPE) using differences between the semi-automated measured diameters and known dimensions. Predictive variables were assessed using a multivariable general linear model. The linear regression slope coefficients (β) were reported to demonstrate effect size and directionality. The APE of the semi-automated measured diameters was higher in ground-glass than solid nodules (β=9.000, p<0.001). APE had an inverse relationship with nodule diameter (mm; β=-3.499, p<0.001) and tube current (mA; β=-0.006, p<0.001). MAPE did not vary based on the ASIR-V level (range: 5.7%-13.1%). Error is dominated by nodule characteristics with a small effect of tube current. Regardless of phantom size, nodule size accuracy is not affected by tube voltage or ASIR-V level, maintaining accuracy while maximizing radiation dose reduction.

Coronary Artery Visualization by Using the 64-row MDCT in Pediatric Patients

We retrospectively evaluated the visualization of pediatric coronary computed tomography angiography (CCTA) images by using the 64-detector row CT scanner between the electrocardiogram-gated helical scan and non-electrocardiogram-gated helical scan. From January 2015 to March 2019, 100 children who underwent CT angiography examination were retrospectively enrolled. Group A consisted of 50 patients with electrocardiogram-gated helical scan. Group B consisted of 50 patients with non-electrocardiogram-gated helical scan. All patients were scanned using a 64-detector row CT scanner (LightSpeed VCT), and helical scans were acquired. The CT scanning parameters were 0.4-s rotation, 0.625-mm slice thickness, 0.24 (group A) helical pitch (beam pitch), 1.375 (group B) helical pitch (beam pitch), 80 kVp, and 50-300 mA (noise index 40). A retrospective method was used for electrocardiogram gated. To compare the radiation dose, CT volume dose index (CTDIvol) and dose length product (DLP) displayed on the console were recorded. The visualization scores of the coronary artery images were compared between each group. In group A, CTDIvol and DLP values were 6.74 (1.05-11.97) mGy and 79.87 (15.90-146.65) mGy·cm, respectively. In group B, CTDIvol and DLP values were 0.51 (0.39-0.95) mGy and 8.15 (6.30-17.50) mGy·cm, respectively. There were significant differences in CTDIvol and DLP values between both groups (p<0.05). The visualization rates for the proximal and distal coronary arteries were 88% and 54% for the right coronary artery, 84% and 58% for the left anterior descending artery, and 66% and 30% for the left circumflex branch in group A, respectively. The visualization rates for the proximal and distal coronary arteries were 52% and 0% for the right coronary artery, 56% and 0% for the left anterior descending artery, and 32% and 0% for the left circumflex branch in group B. In 64-row multidetector computed tomography (MDCT), the visualization rates for the proximal and distal coronary arteries were significantly higher in the electrocardiogram-gated scan, but the exposure dose was several times higher in the pediatric CCTA. For accurate diagnosis in pediatric coronary arteries, electrocardiogram-gated helical scan should be performed.

Optimize scan timing in abdominal multiphase CT: Bolus tracking with an individualized post-trigger delay

PurposeTo conduct a head-to-head comparison in terms of image quality and diagnostic confidence between an individualized post-trigger delay and a conventional fixed post-trigger delay in bolus tracking abdominal multiphase CT. Methods and materialsAbdominal multiphase CT was performed in 104 patients with either of the two bolus tracking strategies: an individualized post-trigger delay (group A) and fixed post-trigger delay of 11 s (group B). All CT scan parameters and contrast media protocol parameters were consistent between the two groups. Quantitative parameters (organs and blood vessels enhancement, image noise, signal-to-noise ratios [SNRs] and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (overall image quality and diagnostic confidence) were compared. Quantitative and qualitative image quality for the two groups were compared using the Mann-Whitney U and independent sample t test. Degrees of agreement between two radiologists were evaluated using the Kappa analysis. ResultsIn the arterial phase (AP), images of group A provided higher attenuation (P ≤ 0.001). Although SNRs of liver, pancreas and aorta were similar in AP between the two groups, CNRs of liver, pancreas and portal vein in group A were significantly higher than those in group B (all P values ≤ 0.002). The overall subjective image quality and diagnostic confidence between the two groups were similar (P = 0.809; P = 0.768). ConclusionCompared to a fixed post-trigger delay using bolus tracking, application of an individualized post-trigger delay can optimize the objective image quality in arterial phase without compromising diagnostic quality in abdominal multiphase CT.

Omalizumab and modification of bronchial asthma natural course

Clinical and molecular heterogeneity of bronchial asthma has been documented in recent years. The search for novel solutions to enhance efficient patient support related first of all to understanding of asthma heterogenic nature and allows to personalize each patient treatment. Biological therapy application can influence to achieve better control at greater extent for patients with severe uncontrolled asthma. Nowadays 5 biological drugs are registered on Russian Federation territory and implemented according to severe asthma phenotypes: anti-IgE, anti-IL-4,13 and anti-IL-5 class therapies. Omalizumab become the first target drug for uncontrolled allergic asthma patients (monoclonal antibody against IgE). This medication is prescribed for uncontrolled moderate and severe allergic (atopic) asthma in patients on basic asthma therapy according GINA step 4 and 5 (Level of evidence A). Clinical trials confidently reported that anti- IgE-therapy reduces the rate of asthma exacerbations, severity of disease in patients with chronic severe asthma on high doses of inhaled steroids or systemic steroids and allows to reduce or withdraw systemic steroids doses in case of steroid-dependent asthma. For the last years special attention led to and demonstrated omalizumab positive effect on airways remodeling and modification of bronchial asthma natural course in adults and children. Antiinflammatory effect of omalizumab is documented. Omalizumab significantly reduces eosinophilic infiltration of submucosal bronchi layer among patients with atopic asthma, sputum eosinophilia, which correlates with reduction of FeNO during biologic treatment, reduces mast cells infiltration of smooth muscle cells in bronchi. Omalizumab significantly reduces the thickness of the bronchial wall, increases the lumen of the bronchi (positive dynamics of CT-scan parameters), which is clinically manifested by increased of FEV1.