The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. The study aimed at the comparison of computed tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chambers, evaluation of their impact on results of non-invasive superficial cardiac mapping.Methods. The study included 93 patients with heart rhythm disorders in whom catheter ablation of arrhythmia was planned. Noninvasive cardiac mapping for arrhythmia localization was performed and included multichannel ECG-registration and CT with intravenous СE (1st group - monophasic (50 patients), 2nd group - split-bolus (18 patients), 3rd group - with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial [VM] contrast-to-noise ratio VM-LV и VM-RV for the left ventricle [LV] and right ventricle [RV], respectively) parameters were compared between the groups. Fusion of ECG and CT data was carried out a semi-automatic mode with a non-invasive imaging complex.Results. Regardless of CE technique, sufficient and homogeneous contrast attenuation was obtained for the left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). In most cases, the enhancement of the right heart was insufficient with the monophasic protocol; the average CT density was lower than 200 HU, VM-RV 0,256. The split-bolus protocol improved visualization of the right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VMRV 0,541); however, there was a heterogeneity of the RA cavity due to artifacts from the superior vena cava (VC) and unenhanced blood from the inferior VC. Pre-bolus administration increased the contrast ratio between RA myocardium and blood due to the improvement of blood CT density in the inferior VC (blood density 294 HU). The quality of RV CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. The split-bolus and with pre-bolus CE protocols improve visualization of the RV, supporting the high-level enhancement of the left heart. The protocol with a pre-bolus is preferable for exact differentiation of the right atrial endocardial contour.

The Relationship between CRP at Admission and Thorax CT Findings in Patients Diagnosed with COVID-19

Introduction: The current study aims to evaluate the relationship between C-reactive protein (CRP) levels, thorax CT findings and CT-SS in patients presenting to the emergency department with COVID-19. Methods: Patients diagnosed with COVID-19 by nasopharyngeal rt-PCR (+) in the emergency department were included in the study. In addition to the CRP, ferritin and D-dimer examinations of patients at admission, thorax CT involvement findings and CT-SS results were recorded. The relationship of CRP value with CT-SS and clinical outcome was evaluated. Results: A total of 974 COVID-19 patients, 572 males (58.7%) and 402 females (41.3%), with a mean age of 59.64±17.34 years, were included in the study. The CRP values of the patients who needed intensive care and needed respiratory support were also significantly higher at admission (95.1 mg/dL vs. 31.05 mg/dL) (p<0.001). The CRP values of the patients who developed any complications during the treatment of COVID-19 were higher (79.9 mg/dL vs. 41.85 mg/dL) (p<0.001). In the case of CRP >124.5, a thorax CT density score 7.35 times higher was determined to be severe. In addition, it was determined that there was a 9.09-fold increase in the incidence of negative imaging findings in terms of COVID-19 in cases where the CRP value was <12.5 mg/dL. Conclusion: The CRP levels of COVID-19 patients measured upon admission to the emergency room are correlated with the severity of lung involvement and are an important predictor of clinical outcomes.

Predefined and data driven CT densitometric features predict critical illness and hospital length of stay in COVID-19 patients

The aim of this study was to compare predefined and data-driven parameters of whole lung CT density histograms to predict critical illness outcome and hospital length of stay in a cohort of 80 COVID-19 patients. CT chest images on segmented lungs were retrospectively analyzed. Functional Principal Component Analysis (FPCA) was used to find the main modes of variations on CT density histograms (F1,F2,F3,F4) in the whole patient cohort. The data driven and a priori CT density features, the CT severity score, the COVID-GRAM score and the patient clinical data were assessed for predicting the patient outcome using logistic regression models stratified for contrast enhanced CT and non-enhanced CT, and survival analysis. ROC analysis identified as best predictors of critically ill status: 87.5th percentile CT density (Q875) - AUC: 0.88 95%CI (0.79 0.94), F1-CT - AUC: 0.87 (0.77 0.93) Standard Deviation (SD-CT)- AUC: 0.86 (0.73, 0.93). Multivariate models combining CT-density predictors and Neutrophil-Lymphocyte Ratio showed the highest accuracy with cross-validated AUCs in the 0.91–0.92 range for contrast CT and 0.82–0.88 range for non-contrast CT. SD-CT, Q875 and F1 score were significant predictors of hospital length of stay while controlling for hospital death using competing risks models. Predefined and data-driven parameters of lung CT density histograms can predict critical illness and length of stay to guide management and resources. FPCA method can be used to interpret the CT density histogram variation in a patient cohort and to extract predictive features with minimal a priori knowledge.

P06.02 Efficacy of Arc based Radiation in children & young adults with Medulloblastoma

BACKGROUND To compare doses to Organs At Risk and assess low dose radiation bath by Cranio Spinal Irradiation in children and young adults with Medulloblastoma between different Techniques. MATERIAL AND METHODS 30 Patients [Median Age: 8(5–23), M: F= 2:1] with Medulloblastoma, planned for Craniospinal Irradiation by Arc based Radiotherapy (VMAT- Elekta) also had an alternative Radiotherapy Plan (IMRT/ 3DCRT) to compare radiation doses to critical OARs (Cochlea, Thyroid, Heart) and low dose radiation bath to Vertebral Body and Supratentorial normal brain). Mean doses of Organs in parallel, Maximum doses of organs in series and Integral Dose was compared. Pre radiation Vertebral Body CT Density (HU) and the absorbed dose to it at various levels was estimated for each patient on the TPS. With the PTV coverage being 95% to the volume, dosimetrically superior plan was chosen for therapy. RESULTS The cohort had a risk stratum in the ratio 4:1 (Standard: High). IHC based molecular subtyping showed WNT, SHH and Non WNT/ Non SHH sub type (3:1:2). For ease of Analysis, the sample was divided among age groups into &lt;8 years, 8–12 years and &gt;12 years. Among the various Age groups, children &lt; 8 years received the lowest dose of 21 Gy to Thyroid via Arc Therapy [(27Gy±4Gy) vs (31Gy± 3Gy)]. Children at 8–12 years received the lowest mean dose of 35 Gy with Arc plan to B/L Cochlea. [(36Gy± 4Gy) vs 41Gy± 4 Gy)]. Significant reduction of Mean dose to the heart was noted in &gt;12 years with Arc [(8 Gy± 1Gy) vs(10 Gy± 2 Gy)]. The Mean CT density by HU of Vertebral Body (Thoraco-Lumbar) estimated were 145 HU, 195 HU and 315 HU in three age groups. Mean Doses to the Vertebrae was significantly lower with VMAT in kids &lt; 8 years. ([3211 cGy ± 80 cGy] vs [3397 cGy ± 70cGy]). Supratentorial brain (basi frontal) received an additional [373.9 cGy ± 0.2Gy] vs[425 cGy ±0.3 Gy]) during PF Boost. CONCLUSION Arc Therapy in Medulloblastoma reduces in field normal tissue radiation dose (Thyroid, Cochlea and heart) at respective ages of &lt;8 years, 8–12 years and &gt; 12 years as well as the low dose radiation bath to structures (Vertebral body and Supratentorial brain) beyond the target volume which may reduce long term complications in children and young adults.

Clinical application of mask region-based convolutional neural network for the automatic detection and segmentation of abnormal liver density based on hepatocellular carcinoma computed tomography datasets

The aim of the study was to use a previously proposed mask region–based convolutional neural network (Mask R-CNN) for automatic abnormal liver density detection and segmentation based on hepatocellular carcinoma (HCC) computed tomography (CT) datasets from a radiological perspective. Training and testing datasets were acquired retrospectively from two hospitals of Taiwan. The training dataset contained 10,130 images of liver tumor densities of 11,258 regions of interest (ROIs). The positive testing dataset contained 1,833 images of liver tumor densities with 1,874 ROIs, and negative testing data comprised 20,283 images without abnormal densities in liver parenchyma. The Mask R-CNN was used to generate a medical model, and areas under the curve, true positive rates, false positive rates, and Dice coefficients were evaluated. For abnormal liver CT density detection, in each image, we identified the mean area under the curve, true positive rate, and false positive rate, which were 0.9490, 91.99%, and 13.68%, respectively. For segmentation ability, the highest mean Dice coefficient obtained was 0.8041. This study trained a Mask R-CNN on various HCC images to construct a medical model that serves as an auxiliary tool for alerting radiologists to abnormal CT density in liver scans; this model can simultaneously detect liver lesions and perform automatic instance segmentation.

A novel lung-avoidance planning strategy based on 4DCT ventilation imaging and CT density characteristics for stage III non-small-cell lung cancer patients

Background Functional planning based merely on 4DCT ventilation imaging has limitations. In this study, we proposed a radiotherapy planning strategy based on 4DCT ventilation imaging and CT density characteristics. Materials and methods For 20 stage III non-small-cell lung cancer (NSCLC) patients, clinical plans and lung-avoidance plans were generated. Through deformable image registration (DIR) and quantitative image analysis, a 4DCT ventilation map was calculated. High-, medium-, and low-ventilation regions of the lung were defined based on the ventilation value. In addition, the total lung was also divided into high-, medium-, and low-density areas according to the HU threshold. The lung-avoidance plan aimed to reduce the dose to functional and high-density lungs while meeting standard target and critical structure constraints. Standard and dose–function metrics were compared between the clinical and lung-avoidance plans. Results Lung avoidance plans led to significant reductions in high-function and high-density lung doses, without significantly increasing other organ at risk (OAR) doses, but at the expense of a significantly degraded homogeneity index (HI) and conformity index (CI; p < 0.05) of the planning target volume (PTV) and a slight increase in monitor units (MU) as well as in the number of segments (p > 0.05). Compared with the clinical plan, the mean lung dose (MLD) in the high-function and high-density areas was reduced by 0.59 Gy and 0.57 Gy, respectively. Conclusion A lung-avoidance plan based on 4DCT ventilation imaging and CT density characteristics is feasible and implementable, with potential clinical benefits. Clinical trials will be crucial to show the clinical relevance of this lung-avoidance planning strategy.

Favorable Trends of Lung Cancer Mortality-to-Incidence Ratios in Countries With High Computed Tomography Density

Background: Prognoses for lung cancer deteriorate dramatically with the progression of cancer stages. Therefore, early screening by techniques such as low-dose computed tomography (LDCT) is critical. However, the epidemiology regarding the association between the popularization of CT and the prognosis for lung cancer is not known.Methods: Data were obtained from GLOBOCAN and the health data and statistics of World Health Organization. MIRs and the changes in MIR over time (𝛿MIR), which were calculated as the difference between MIRs in 2018 and 2012, were used to evaluate the correlation to CT density disparities via Spearman's rank correlation coefficient.Results: Countries with zero CT density presented a relatively low incidence crude rate and a relatively high MIR in 2018 and a negative 𝛿MIR. Conversely, countries with CT density over 30 had a positive 𝛿MIR. The CT density was significantly associated with human development index (HDI) score and MIR in 2018 but demonstrated no association with MIR in 2012. The linear correlation between CT density and 𝛿MIR also shows a significant association.Conclusion: CT density was significantly associated with MIR in 2018 and with 𝛿MIR, indicating favorable clinical outcomes in countries with popularization of CT.

The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. Comparison of computer tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chamber, definition it’s influence on results of non-invasive superficial cardiac mapping.Materials and methods. The study included 93 patients with heart rhythm disorders who planned catheter ablation of arrhythmia. Noninvasive cardiac mapping was made for topical diagnostics. It includes multichannel ECG-registration and CT with intravenous СE (1st group monophasic (50 patients), 2nd group split-bolus (18 patients), 3rd group with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial contrast-to-noise ratio VM-LV и VM-RV for left ventricle (LV) and right ventricle (RV), respectively) parameters were compared between groups. Fusion of ECG and CT data was made semi-automatic with diagnostic complex «Amycard 01К».Results. Regardless of CE technique was noted sufficient and homogeneous contrast attenuation of left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). Enhancement of right heart was insufficient with monophasic protocol, in most cases the average CT density was lower than 200 HU, VM-RV 0,256. Split-bolus protocol improves visualization of right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VM-RV 0,541), however there was heterogeneity of RA cavity because of artifacts from superior vena cava (VC) and unenhanced blood from inferior inferior VC. Using of pre-bolus increases contrast ratio between RA myocardium and blood due to increasing CT density of blood in inferior VC (blood density 294 HU). Quality of right ventricle CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. CE protocols split-bolus and with pre-bolus improve visualization of right ventricle, supporting the high level enhancement of left heart. Protocol with pre-bolus is preferable for exact differentiation of right atrial endocardial contour.