Lung Window Research Articles

CT chest - A rapid screening tool in COVID-19 pandemic.

The COVID-19 pandemic has affected a significant proportion of the population worldwide. Symptoms and signs of chest infections are commonly reported; however, RT PCR is the primary diagnostic modality. In this context, we wish to report on some results from an advanced tertiary imaging centre in south India on the use of CT imaging of the chest in COVID suspected patients. From March 2020 to August 2020, Screening CT Chest was done for all patients undergoing elective surgeries, who were asymptomatic for Viral infection, people exposed to COVID positive patients before one week and all patients who had mild symptoms like cough, body ache, anosmia, loss of taste, mild fever (<100°F), who didn’t require admission. All these patients underwent HRCT and noncontract Spiral CT in the same sitting and the findings of Ground glass opacities, Septal thickening, crazy paving pattern and patchy consolidations or mixed patterns[[1]] were considered positive by CORADS.[[2]] The study included all CT screen positive patients who underwent RTPCR for COVID and the results were analysed. Chest CT images were evaluated by two radiologists on both mediastinal (width 350 HU, level 40 HU) and lung (width 1500 HU, level -500 HU) window settings defining the pulmonary lesions according to their location, density, shape, and margin.

Impact of computed tomography window settings on clinical T classifications and prognostic evaluation of patients with subsolid nodules.

To investigate the impact of lung window (LW) and mediastinal window (MW) settings on the clinical T classifications and prognostic prediction of patients with subsolid nodules. Seven hundred and nineteen surgically resected subsolid nodules were reviewed, grouping into pure ground-glass nodules (n = 179) or part-solid nodules (n = 540) using LW. Interobserver agreement on nodule classifications was assessed via kappa-value, and predictive performance of the solid portion measurement in LW and MW for pathological invasiveness and malignancy were compared using receiver-operating characteristic analysis. Cox regression was used to identify prognostic factors. Prognostic significance of T classifications based on LW (c[l]T) and MW (c[m]T) was evaluated by Kaplan-Meier method after propensity score matching. The performance of c(m)T for discrimination survival was estimated via the concordance index (C-index), net reclassification improvement and integrated-discrimination improvement. By adopting MW, 124 part-solid nodules were reclassified as pure ground-glass nodules, and interobserver agreement improved to 0.917 (95% confidence interval 0.888-0.946). The solid portion size under MW more strongly predicted pathological invasiveness (P = 0.030), but did not better predict pathological malignancy. For remaining 416 part-solid nodules, c(l)T and c(m)T were both independent risk factors. c(m)T led to T classifications shifts in 321 nodules (14 upstaged and 307 downstaged) with no significant prognostic difference existing between the shifted c(m)T and matching c(l)T group after propensity score matching. The corrected C-index was improved to 0.695 (0.620-1.000) when adopting c(m)T with no significant difference in net reclassification improvement (P = 0.098) and integrated-discrimination improvement (P = 0.13) analysis. As there is no significant benefit provided by MW in evaluating clinical T classification and prognosis, the current usage of LW is appropriate for assessing subsolid nodules.

Selection of Pathological N0 (pN0) in Clinical IA (cIA) Lung Adenocarcinoma by Imaging Findings of the Main Tumor

Objectives: We would like to clarify the imaging findings of the main tumor that may omit the requirement for lymph node dissection in clinical IA (cIA) lung adenocarcinoma.Methods: A total of 336 patients with cIA lung adenocarcinomas with normal preoperative carcinoembryonic antigen (CEA) who underwent surgical resection were analyzed. We investigated the association between various computed tomography (CT) imaging findings or the maximum standardized uptake value (SUVmax) of fluorodeoxyglucose-position emission tomography (FDG-PET) and lymph node metastasis. The maximum tumor diameter was calculated from the CT images using both the lung window setting (LD) and mediastinal window setting (MD). The diameter of the solid component (CD) was defined as consolidation diameter in lung window setting. The solid component ratio (C/T) was defined as CD/LD.Results: SUVmax, MD, and C/T were independent factors related to lymph node metastasis, but CD was not (p = 0.38). The conditions required for the positive predictive value (PPV) to reach 100% were 10.6 mm for MD, 12.5 mm for CD, and 0.55 for C/T. SUVmax did not reach 100%.Conclusions: In cIA lung adenocarcinoma with CEA in the normal range, we found that it may be possible for lymph node dissection to be omitted by MD, CD, and C/T.

CT Pulmonary Angiogram with Reduced Radiation Exposure at Low Tube Kilovoltage

This study's primary goal is to assess the image quality and radiation dose of the low-dose 80kV computed tomography pulmonary angiogram (CTPA) protocol compared to the standard 100kV CTPA protocol for the assessment of pulmonary embolism (PE). The study consisted of 100 patients who had clinically suspected pulmonary embolism and required a CTPA. Patients underwent imaging with a 320-row multi-detector Toshiba Aquilion One Genesis Edition in the absence of the proprietary radiation reduction software known as forward projected model-based Iterative Reconstruction Solution (commercial acronym 'FIRST'). Participants were divided into two groups: A and B. Group A was composed of 50 patients who were allocated to standard CT protocol using a 100 kV exposure setting and all other settings set as a standard by the manufacturer. Group B was composed of 50 patients who were allocated to a CTPA with a low-dose 80kV protocol, standard deviation level 8, an effective mAs of 258, reconstruction algorithm-kernel FC 51 within the lung window, and tube current modulation. A considerable decrease in radiation dose was observed with the low-dose CTPA protocol. The mean radiation dose was also decreased by 66% while using the 80kV protocol than when utilising a standard 100kV technique; this was achieved without compromising this study's diagnostic value. Furthermore, the contrast enhancement was considerably more significant, up to 40% higher when using 80kV. The study found that a low tube voltage of 80kV CTPA protocol resulted in a considerable decrease in radiation dose and improved contrast enhancement without sacrificing the examinations' diagnostic utility.

Post Chemo Lung Toxicity: A Less Visited Domain

Background: Post-anticancer chemotherapy changes in lung parenchyma is an important and challenging aetiology for radiologists presenting not uncommonly in cancer patients. Early diagnosis of post-chemotherapy lung toxicity have serious implications on patient's health.Objective: To evaluate post-chemotherapy cancer patients for pulmonary toxicity and establish their association with frequency of chemotherapy cycles and time lapse since last cycle.Material and Methods: This retrospective study was conducted in Kuwait teaching Hospital from January 2018 till December 2018. A total of 204 patients were evaluated with age ranging from 3 to 78 years including 63 male and 141 female patients. Chest CT scan had been done on16 slice Toshiba CT scanner in Radiology department of Kuwait Teaching Hospital. Images were evaluated in axial, coronal and sagittal planes and in lung and soft tissue window on workstation. Data like patient age ,gender , malignancy , number of chemotherapy cycles received , time lapse since last chemotherapy cycle, common CT manifestations of lung toxicity and CT lung findings unrelated to chemotherapy regimens ;was collected and subjected to statistical analysis. Results: Out of the total 204 patients, who already had anticancer therapy, 135 patients (66.2%) did not show any pulmonary abnormality on CT chest . 11 patients (5.4%) showed chemotherapy related pulmonary findings on CT. 46 patients (22.5%) showed CT chest findings which were incidental and irrelevant to chemotherapy.12 patients (5.9%) had both chemotherapy related pulmonary toxicity changes and incidental findings. The types of post chemotherapy CT lung changes were divided into ground-glass haze, ground glass haze with bronchiectasis, ground glass haze with septal thickening giving crazy paving appearance, patches of consolidation and reticular thickening. 10 patients had sole finding of ground glass haze only (43.5%) whereas 4 patient showed ground glass haze with bronchiectatic changes(17.4 %) and 2 patients depicted a crazy paving appearance (8.7%). Significant association (p=0.00) was noted between number of chemotherapy cycles and above mentioned CT lung findings .No positive correlation was present between time lapse since last chemotherapy cycle and these CT lung findings. Conclusion: Ground glass attenuation was found to be the most profounding feature of post chemotherapy lung CT changes.

PERANAN HEART RATE TERHADAP KUALITAS CITRA PENGGUNAAN “COVID-19” WINDOW UNTUK PEMERIKSAAN CT-SCAN THORAX POLOS PADA PASIEN SUSPEK COVID-19

Background: Non-contrast chest CT-Scan is one of the COVID-19 screening methods. At Panti Waluyo hospital of Surakarta, Non-contrast chest CT-Scan did not use the HRCT technique, low-dose technique, Lung Window, and Mediastinum Window, but used a standard-dose technique and “COVID-19” window.&#x0D; Methods: The research was conducted at Panti Waluyo hospital of Surakarta, scanning process using GE Brightspeed 8 Slices CT-Scan. The position of the patient is supine feet first, the midline is at the midsagittal plane and axillary line, the scanning process begins with a vertical and horizontal scout photo, scanning area from Thoracal 1st to lumbar 3rd, using a helical scan, and “COVID-19” window with 120 kV, 100 mA, 0.8 s, 5 mm slice thickness, FoV 34 cm, gantry tilt 0 °, reconstruction 1.25 mm, pitch 1.35: 1, window width 1600, and window level -250.&#x0D; Results: The expertise of Radiologists indicates bilateral pneumonia (typical COVID-19). The "COVID-19" window presents GGO and clarifies the difference between GGO and lung consolidation. It shows the contour of the heart and part of the liver, without adding another window. So, it can increase the effectiveness of time and radiological film.&#x0D; Conclusions: For non-contrast chest CT-scan in patients with suspected COVID-19, it is better to use the “COVID-19” window than the lung or mediastinal window.

Multi-Window CT Based Radiological Traits for Improving Early Detection in Lung Cancer Screening.

Rationale and ObjectivesEvaluate ability of radiological semantic traits assessed on multi-window computed tomography (CT) to predict lung cancer risk.Materials and MethodsA total of 199 participants were investigated, including 60 incident lung cancers and 139 benign positive controls. Twenty lung window features and 2 mediastinal window features were extracted and scored on a point scale in three screening rounds. Multivariate logistic regression analysis was used to explore the association of these radiological traits with the risk of developing lung cancer. The areas under the receiver operating characteristic curve (AUROC), sensitivity, specificity, and positive predictive value (PPV) were computed to evaluate the best predictive model.ResultsCombining mediastinal window-specific features with the lung window features-based model significantly improves performance compared to individual window features. Model performance is consistent both at baseline and the first follow-up scan, with an AUROC increased from 0.822 to 0.871 (p = 0.009) and from 0.877 to 0.917 (p = 0.008), respectively, for single to multi-window feature models. We also find that the multi-window CT based model showed better specificity and PPV, with PPV at the second follow-up scan improved to 0.953.ConclusionWe find combining window semantic features improves model performance in identifying cancerous nodules. We also find that lung window features are more informative compared to mediastinal features in predicting malignancy.

Accuracy of Deformable Image Registration for Reirradiation of Lung Cancer Following Stereotactic Body Radiotherapy

Stereotactic body radiotherapy (SBRT) for lung cancer typically causes radiographic lung changes that can affect the registration accuracy at the time of reirradiation. In this study, we investigate the accuracy of deformable image registration (DIR) in the presence of post SBRT lung changes using anatomical landmarks. We hypothesize that DIR accuracy is worse in regions near radiographic changes than in normal lung tissue. Planning, 3-, 6-, and 12-month follow-up CT images were deformably registered for 10 patients exhibiting radiographic lung changes following SBRT. Several multi-pass b-spline based DIRs were performed using a commercially available algorithm by varying the target intensity window and the structures with overridden image intensities. The structures included: the planning target volume (PTV) and ground glass (GG), and consolidated (C) radiographic changes, while the intensity windows investigated included: full image contrast, lung window (-1024HU to 200 HU), and mediastinum window (-135HU to 215HU). Landmark points were manually located in both the treated lung (mean 26.5 points, range 17-30 per scan within 5cm of the PTV) and contralateral normal lung (mean 29.7 points, range 29-30). Accuracy was evaluated by calculating the average 3D landmark registration error. The Pearson correlation coefficient was used to investigate the influence of the PTV, GG, and C lung volumes and normal lung registration error on the treated region registration error. For all time points considered together, the most accurate registration near treated tissue involved masking both the PTV and GG lung changes and using full image contrast. The average landmark error near the treated region with this registration was 7.7 +/- 4.9 mm and 5.2 +/- 3.5mm in the normal lung. The landmark error for the individual time points, 3-, 6-, and 12-month respectively, were 3.7mm, 9.8mm, and 9.8mm near the treated region and 4.8mm, 5.7 and 5mm in the normal lung tissue. Landmark errors at 3-months were strongly correlated with the volume of the GG (rˆ2 = 0.84) and C (rˆ2 = 0.84) lung changes. The 6- and 12-month landmark errors were moderately correlated with GG (rˆ2 = 0.29, rˆ2 = 0.43) and C (rˆ2 = 0.31, rˆ2 = 0.47) volumes. There was moderate correlation between landmark errors near the treated region and normal tissue that increases over time from rˆ2 = 0.28 at 3 months to rˆ2 = 0.69 at 12 months. No strong correlation was found with the PTV volume. Landmark registration errors in the treated region can be a few millimeters larger than in normal tissue and appear to increase with time, before stabilizing. There is also an increasing correlation over time between the normal tissue registration errors and those in the treated region. DIR uncertainty in the treated and normal lung needs to be considered during retreatment composite planning.

4DCT Reconstruction With a Low-Density Target

4DCT technology is used in radiation oncology to estimate the internal motion of organs due to breathing. While used to determine the internal target volume (ITV), there is a lack of publications that show the precision and accuracy of 4DCT technology with low density targets. In this study, we investigate the accuracy of the Minimum Intensity Projection (mIP) when the target is air and the surrounding medium is acrylic. A Quasar phantom with a 4D PET-CT insert (P/N: 500-3318) filled with air was utilized for the study. The scanning unit was a GE Optima Scanner utilizing Real-Time Positioning ManagementTM (RPM) System. The breathing period is a sinusoidal breathing pattern set to 20 cycles per minute with 4 cm amplitude. A set of two different studies was performed: static, where the phantom was scanned without motion, and dynamic-tracking, where the moving phantom was tracked using RPM. For the dynamic-tracking study, 3D images were created for each of the 10 breathing phases utilizing phase sorting. From these, a 3D mIP image and an average 3D image (AVG) were created. The air cavity was contoured in both studies using Lung window level preset and the diameter, height and volume were determined. The true ITV was calculated using vendor insert specifications. The amplitude of motion was obtained by subtracting the static height from the mIP and the AVG and compared with the amplitude set on the phantom. Next, a CBCT was performed on the phantom using a linear accelerator. The volume of air was contoured on this scan using the same preset as before, and this volume was compared to the volume on the AVG reconstructed 3D image. The mIP had a measured amplitude of 3.97 cm compared with the true set amplitude of 4cm and a target volume of 41.2 cm3 compared with the true ITV volume of 42.74 cm3 resulting in a difference from the true values of -0.8% and -3.6%, respectively. The AVG measured amplitude was 3.90 cm and target volume were 37.2 cm3, resulting in a difference of 2.5% and -13.0%, respectively. The CBCT had a measured amplitude of motion of 3.88 cm, which resulted in a difference from the true amplitude of -3.0%, but when compared against the AVG only resulted in a difference of -0.5%, with the AVG being slightly larger. In addition, the target volume of the CBCT was 36.4 cm3, which was slightly smaller than the AVG target volume of 37.2 cm3, with a difference of -2.2%. This study shows that the motion of a low-density target surrounded by high density material can be accurately estimated using 4DCT technology. The mIP, which is used to determine the ITV margins for treatment for low density targets, accurately depicted the motion of the target to within a millimeter. In addition, the AVG, which is the scan used for treatment planning, accurately matched the CBCT observed target. Further study is required on non-sinusoidal motion to determine 4DCT accuracy.

Intrathoracic use of a small ultrasonic probe for localizing small lung tumors in thoracoscopic surgery: Empirical results and comparison with preoperative CT images.

To evaluate the use of a small mobile ultrasound probe to localize small lung tumors during thoracoscopic surgery under thoracic CO2 insufflation. We prospectively enrolled 20 patients (26 tumors) scheduled to undergo thoracoscopic pulmonary wedge resection between April 2016 and October 2018. Ultrasonographic tumor detection was performed with an ARIETTA 850 and L51K probe (Hitachi, Tokyo, Japan). Ultrasonography was repeated after achieving adequate lung collapse under a positive intrathoracic pressure of 8-15mmHg. The appearance on preoperative CT versus the ultrasonographic localization was compared for each tumor. The receiver operating characteristic curves were compared for the tumor dimension of the lung window, consolidation dimension of the lung window, tumor dimension of the mediastinal window (MD), and tumor depth from the lung surface. The average age was 62years (range 42-79years), average pathological tumor size was 9mm (range 3-22mm), and average tumor depth was 6mm (range 1-25mm). Although no tumors could be visualized before lung collapse, 22 tumors (85%) were detectable with ultrasonography after lung collapse. Of these 22 tumors, 16 were well-depicted, while six were poorly delineated. MD showed the largest area under the receiver operating characteristic curve (0.81), and tumors with a MD of ≤ 6mm had a high risk of difficult localization using ultrasonography. This ultrasonographic method obtained high tumor detection rates, especially for tumors with a MD > 6mm. Tumors with a MD ≤ 6mm may require another localization method. University Hospital Medical Information Network Clinical Trials Registry (UMIN000036921).

Clinical T category for lung cancer staging: A pragmatic approach for real-world practice.

BackgroundTo determine which components should be measured and which window settings are appropriate for computerized tomography (CT) size measurements of lung adenocarcinoma (ADC) and to explore interobserver agreement and accuracy according to the eighth edition of TNM staging.MethodsA total of 165 patients with surgically resected lung ADC earlier than stage 3A were included in this study. One radiologist and two pulmonologists independently measured the total and solid sizes of components of tumors on different window settings and assessed solidity. CT measurements were compared with pathologic size measurements.ResultsIn categorizing solidity, 25% of the cases showed discordant results among observers. Measuring the total size of a lung adenocarcinoma predicted pathologic invasive components to a degree similar to measuring the solid component. Lung windows were more accurate (intraclass correlation [ICC] = 0.65–0.81) than mediastinal windows (ICC = 0.20–0.72) at predicting pathologic invasive components, especially in a part‐solid nodule. Interobserver agreements for measurement of solid components were good with little significant difference (lung windows, ICC = 0.89; mediastinal windows, ICC = 0.91). A high level of interobserver agreement was seen between the radiologist and pulmonologists and between residents (from the division of pulmonology and critical care) versus a fellow (from the division of pulmonology and critical care) on different windows.ConclusionsA considerable percentage (25%) of discrepancies was encountered in categorizing the solidity of lesions, which may decrease the accuracy of measurements. Lung window settings may be superior to mediastinal windows for measuring lung ADCs, with comparable interobserver agreement and moderate accuracy for predicting pathologic invasive components.Key pointsSignificant findings of the study Lung window settings are better for evaluating part‐solid lung adenocarcinoma (ADC), with comparable interobserver agreement and moderate accuracy for predicting pathologic invasive components. The considerable percentage (25%) of discrepancies in categorizing solidity of the lesions may also have decreased the accuracy of measurements. What this study adds For accurate measurement and categorization of lung ADC, robust quantitative analysis is needed rather than a simple visual assessment.

Pulmonary tuberculosis masquerading as coronavirus disease 2019 in an HIV-infected individual with advanced immune suppression

Pulmonary tuberculosis masquerading as coronavirus disease 2019 in an HIV-infected individual with advanced immune suppression

Efficacy of measuring the invasive diameter of lung adenocarcinoma using mediastinal window settings: A retrospective study.

The recently published 8th edition of the tumor node and metastasis Classification of Lung Cancer proposes using the maximum dimension of the solid component of a ground glass nodule (GGN) for the T categorization. However, few studies have investigated the collection of this information when using mediastinal window settings. In this study, we evaluated tumor measurement data obtained from computed tomography (CT) scans when using mediastinal window settings.This study included 202 selected patients with persistent, partly solid GGNs detected on thin-slice CT after surgical treatment between 2004 and 2013. We compared the differences in tumor diameters measured by 2 different radiologists using a repeated-measures analysis of variance. We divided the patients into 2 groups based on the clinical T stage (T1a+T1b vs T1c) and estimated the probability of overall survival (OS) and disease-free survival (DFS) using Kaplan–Meier curves.The study included 94 male and 108 female patients. The inter-reviewer differences between tumor diameters were significantly smaller when the consolidation to maximum tumor diameter ratio was ≤0.5. The 2 clinical groups classified by clinical T stage differed significantly with respect to DFS when using the mediastinal window settings. However, no significant differences in OS or DFS were observed when using the lung window setting.Our study yielded 2 major findings. First, the diameters of GGNs could be measured more accurately using the mediastinal window setting. Second, measurements obtained using the mediastinal window setting more clearly depicted the effect of clinical T stage on DFS.

Anatomical Assessment of the Thorax in the Neonatal Foal Using Computed Tomography Angiography, Sectional Anatomy, and Gross Dissections.

The purpose of this study was to correlate the anatomic features of the normal thorax of neonatal foals identified by CTA, with anatomical sections and gross dissections. Contrast-enhanced transverse CTA images were obtained in three neonatal foals using a helical CT scanner. All sections were imaged with a bone, mediastinal, and lung windows setting. Moreover, cardiac volume-rendered reconstructed images were obtained. After CT imaging, the cadaver foals were sectioned and dissected to facilitate the interpretation of the intrathoracic cardiovascular structures to the corresponding CTA images. Anatomic details of the thorax of neonatal foals were identified according to the characteristics of CT density of the different organic tissues and compared with the corresponding anatomical sections and gross dissections. The information obtained provided a valid anatomic pattern of the thorax of foals, and useful information for CTA studies of this region.

Application of CareDose 4D combined with Karl 3D technology in the low dose computed tomography for the follow-up of COVID-19

BackgroundCoronavirus disease 2019 (COVID-19) is a highly infectious disease caused by the new coronavirus. Previous studies have shown that the chest CT examination plays an important role in the diagnosis and monitoring of COVID-19. However, some patients with COVID-19 had low white blood cell counts and reduced lymphocyte ratios. Multiple CT examinations may cause radiation damages as well as increase the apoptosis of peripheral blood lymphocytes. A new low-dose CT method should be developed because the regular CT may aggravate the disease.MethodSixty cases were randomly divided into the study group (n = 30) and control group (n = 30). The lung window was reconstructed by Karl 3D iterative technique in the study group. The image quality was subjectively evaluated by two senior chest group diagnostic physicians using a 5-point double-blind method. The value of CT measurement and its standard deviation (SD) was used as an objective evaluation criteria. The volume of CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED) from the two groups were compared and analyzed statistically.ResultThere was no significant difference in the occurrence rates of ground glass opacities, consolidation, crazy-paving pattern, fiber cable shadow and axial interstitial thickening between the study group and control group (p > 0.05). In addition, no significant difference was found for the subjective score of overall image quality and image noise level (SD) between the two groups (p > 0.05). However, significant differences was found in CTDIvol, DLP, and ED between the study group and the control group (p < 0.05). The effective dose of the study group was reduced by 76% compared to the control group.ConclusionCareDose 4D low-dose scanning combined with Karl 3D iterative reconstruction technology can not only greatly reduce the radiation dose, but also provide images that meet the diagnostic criteria of COVID-19, which can be used as a routine method for the follow-up of COVID-19 patients.

Computed tomography of the lungs of healthy captive red-footed tortoises (Chelonoidis carbonaria)

Respiratory tract diseases of various origins are commonly diagnosed in captive testudines. In tortoises, computed tomography is considered the method of choice for evaluation of the lung. Our objective was to describe the anatomy of the lung parenchyma of red-footed tortoises (Chelonoidis carbonaria) using computed tomography to estimate the normal radiodensity of the lung and lung volume. We selected 10 healthy adult red-footed tortoises of similar size. Computed tomography images were obtained using lung window settings and multiplanar reconstructions for quantitative evaluation using the histogram method. The tortoises were not sedated and were allowed to maintain their head and limbs retracted during the exam. Data were expressed in mean and standard deviation. In testudines, the lung is divided into left and right, and there are no lobes. There is a main bronchus in each lung. Mean values for radiodensity and lung volume were −811.30 ± 19.82 Hounsfield units and 942.12 ± 189.29 cm³, respectively. These findings can be useful as a normal range for evaluating red-footed tortoises in a clinical setting. It also serves as a basis for future studies regarding specific patterns in lung disease.

Radiation dose and image quality of noncontrast chest CT in domestic and imported main stream manufacturers

Objective: To compare the radiation dose and image quality of noncontrast chest CT and detection of ground-glass opacity pulmonary nodules (GGN) in domestic 128-slice spiral CT with the other CT scanners from three main stream manufacturers. Methods: From May 8, 2018 to October 31, 2018, noncontrast chest CT images from Neusoft 128-slice CT (75 males, 25 females, (42±16) years), dual-source 64-slice CT (53 males, 47 females, (50±16) years) and dual-source 128-slice CT scanners(69 males, 31 females, (62±17) years), Toshiba 128-slice CT (51 males, 49 females, (58±13) years) and GE 128-slice CT scanner (55 males, 45 females, (60±10) years) were collected in Eastern Theater Command and Tianjin People's Hospital. Radiation dose and image quality were evaluated.GGN detected both in Neusoft CT and dual-source CT scanners were used to analyze the displaying ability of lesions. Results: The noise in lung window of Neusoft CT ((37.8±4.9) HU) was higher than that of other mainstream CT scanners, and the noise in mediastinal window ((8.4±1.9) HU) was lower than that of GE 128-slice CT ((9.8±3.2) HU), but higher than that of dual-source CT and Toshiba 128-slice CT ((6.9±3.5)HU) (P<0.05). The absolute value of lung SNR in Neusoft CT was lower than that of other mainstream CT scanners, and the SNR in aorta (4.6±1.3) was lower than those of dual-source CT and Toshiba 128-slice CT(6.8±2.2) (P<0.05), but was not statistically significant compared with GE 128-slice CT (5.0±1.7). The mean CT value of upper lung ((-863±31) HU) at Neusoft CT was higher than 128-row dual-source CT ((-869±35) HU), and the mean CT value of aorta ((37±7) HU) was lower than that of Toshiba 128-slice CT((42±7) HU) and GE 128-slice CT ((45±9) HU) (P<0.05), while the mean CT values of the remaining lung and aorta were not statistically significant (P>0.05). The two readers had good to excellent consistency for image quality in five scanners (the highest kappa value=0.984). The delineation ability of Neusoft CT for GGN boundary was lower than that of dual-source CT (P<0.05), but had similar abilities to display the solid components, lobulation, burring, vacuoles, vascular bundle sign and pleural depression sign of GGN (all P>0.05). Radiation dose of Neusoft CT was lower than Toshiba 128-slice CT, but higher than dual-source 64-sliceCT and GE 128-slice CT scanners (P<0.05). Conclusions: With lower radiation dose than Toshiba 128-slice CT, Neusoft CT chest examination can meet the requirements of clinical diagnosis, but higher radiation dose and the lower image quality than dual-source CT and GE 128-slice CT shown in this study indicate further improvement is needed in terms of software and hardware.

Ventilation and Perfusion at the Alveolar Level: Insights From Lung Intravital Microscopy.

Intravital microscopy (IVM) offers unique possibilities for the observation of biological processes and disease related mechanisms in vivo. Especially for anatomically complex and dynamic organs such as the lung and its main functional unit, the alveolus, IVM provides exclusive advantages in terms of spatial and temporal resolution. By the use of lung windows, which have advanced and improved over time, direct access to the lung surface is provided. In this review we will discuss two main topics, namely alveolar dynamics and perfusion from the perspective of IVM-based studies. Of special interest are unanswered questions regarding alveolar dynamics such as: What are physiologic alveolar dynamics? How do these dynamics change under pathologic conditions and how do those changes contribute to ventilator-induced lung injury? How can alveolar dynamics be targeted in a beneficial way? With respect to alveolar perfusion IVM has propelled our understanding of the pulmonary microcirculation and its perfusion, as well as pulmonary vasoreactivity, permeability and immunological aspects. Whereas the general mechanism behind these processes are understood, we still lack a proper understanding of the complex, multidimensional interplay between alveolar ventilation and microvascular perfusion, capillary recruitment, or vascular immune responses under physiologic and pathologic conditions. These are only part of the unanswered questions and problems, which we still have to overcome. IVM as the tool of choice might allow us to answer part of these questions within the next years or decades. As every method, IVM has advantages as well as limitations, which have to be taken into account for data analysis and interpretation, which will be addressed in this review.

COVID19 –Nuclear Medicine Departments, be prepared!

COVID19 –Nuclear Medicine Departments, be prepared!

Deep Regression via Multi-Channel Multi-Modal Learning for Pneumonia Screening

Pneumonia screening is one of the most crucial steps in the pneumonia diagnosing system, which can improve the work efficiency of the radiologists and prevent delayed treatments. In this paper, we propose a deep regression framework for automatic pneumonia screening, which jointly learns the multi-channel images and multi-modal information (i.e., clinical chief complaints, age, and gender) to simulate the clinical pneumonia screening process. We demonstrate the advantages of the framework in three ways. First, visual features from multi-channel images (Lung Window Images, High Attenuation Images, Low Attenuation Images) can provide more visual features than single image channel, and improve the ability of screening pneumonia with severe diseases. Second, the proposed framework treats chest CT scans as short video frames and analyzes them by using Recurrent Convolutional Neural Network, which can automatically extract multiple image features from multi-channel image slices. Third, chief complaints and demographic information can provide valuable prior knowledge enhancing the features from images and further promote performance. The proposed framework has been extensively validated in 900 clinical cases. Compared to the baseline, the proposed framework improves the accuracy by 2.3% and significantly improves the sensitivity by 3.1%. To the best of our knowledge, we are the first to screen pneumonia using multi-channel images, multi-modal demographic and clinical information based on the large scale clinical raw dataset.