Deep feature-domain matching for cardiac-related component separation from a chest electrical impedance tomography image series: proof-of-concept study.

Objectives.The cardiac-related component in chest electrical impedance tomography (EIT) measurement is of potential value to pulmonary perfusion monitoring and cardiac function measurement. In a spontaneous breathing case, cardiac-related signals experience serious interference from ventilation-related signals. Traditional cardiac-related signal-separation methods are usually based on certain features of signals. To further improve the separation accuracy, more comprehensive features of the signals should be exploited.Approach.We propose an unsupervised deep-learning method called deep feature-domain matching (DFDM), which exploits the feature-domain similarity of the desired signals and the breath-holding signals. This method is characterized by two sub-steps. In the first step, a novel Siamese network is designed and trained to learn common features of breath-holding signals; in the second step, the Siamese network is used as a feature-matching constraint between the separated signals and the breath-holding signals.Main results.The method is first tested using synthetic data, and the results show satisfactory separation accuracy. The method is then tested using the data of three patients with pulmonary embolism, and the consistency between the separated images and the radionuclide perfusion scanning images is checked qualitatively.Significance.The method uses a lightweight convolutional neural network for fast network training and inference. It is a potential method for dynamic cardiac-related signal separation in clinical settings.

Quantitative lung perfusion blood volume using dual energy CT-based effective atomic number (Zeff ) imaging.

BACKGROUND: Iodine material images (aka iodine basis images) generated from dual energy computed tomography (DECT) have been used to assess potential perfusion defects in the pulmonary parenchyma. However, iodine material images do not provide the needed absolute quantification of the pulmonary blood pool, as materials with effective atomic numbers (Zeff ) different from those of basis materials may also contribute to iodine material images, thus confounding the quantification of perfusion defects. PURPOSE: (i) To demonstrate the limitations of iodine material images in pulmonary perfusion defect quantification and (ii) to develop and validate a new quantitative biomarker using effective atomic numbers derived from DECT images. METHODS: The quantitative relationship between the perfusion blood volume (PBV) in pulmonary parenchyma and the effective atomic number (Zeff ) spatial distribution was studied to show that the desired quantitative PBV maps are determined by the spatial maps of Zeff as PB V Z eff ( x ) = a Z eff ß ( x ) + b , where a, b, and ß are three constants. Namely, quantitative PB V Z eff is determined by Zeff images instead of the iodine basis images. Perfusion maps were generated for four human subjects to demonstrate the differences between conventional iodine material image-based PBV (PBViodine ) derived from two-material decompositions and the proposed PB V Z eff method. RESULTS: Among patients with pulmonary emboli, the proposed PB V Z eff maps clearly show the perfusion defects while the PBViodine maps do not. Additionally, when there are no perfusion defects present in the derived PBV maps, no pulmonary emboli were diagnosed by an experienced thoracic radiologist. CONCLUSION: Effective atomic number-based quantitative PBV maps provide the needed sensitive and specific biomarker to quantify pulmonary perfusion defects.

Study of the value of SPECT lung perfusion imaging in optimizing lung cancer radiotherapy plan for lung function protection / 中华放射肿瘤学杂志

Objective:To evaluate the application value of SPECT lung perfusion imaging in guiding radiotherapy path, optimizing the radiotherapy plan for lung cancer and protecting lung function during radiotherapy for locally advanced non-small cell lung cancer.Methods:In this study, 84 patients with stage Ⅲ non-resectable non-small cell lung cancer were randomly divided into the control group ( n=44) and observation group ( n=40). In the control group, radiotherapy plan based on conventional CT images was delivered, and two plans based on the lung function information suggested by conventional CT and SPECT lung perfusion imaging: P1 and P2 were given in the observation group. All patients in the observation group were finally treated according to the P2 plan. The incidence of radiation pneumonitis, and changes in lung function before and after radiotherapy were statistically compared between two groups. The dose-volume parameters of P1 and P2 were statistically compared. Results:After the plan was optimized, the incidence of radiation pneumonitis in the observation group was significantly reduced and the decline of lung function was significantly improved (both P≤0.001). The functional dose parameters were significantly improved in the P2 plans (both P<0.05), whereas the irradiation dose of organs at risk did not significantly change ( P>0.05). Conclusion:SPECT lung perfusion imaging optimizes the intensity-modulated radiotherapy plan, which can reduce the functional lung dose and increase the tumor radiotherapy dose without increasing the irradiation dose of other organs at risk.

From Early Morphometrics to Machine Learning-What Future for Cardiovascular Imaging of the Pulmonary Circulation?

Imaging plays a cardinal role in the diagnosis and management of diseases of the pulmonary circulation. Behind the picture itself, every digital image contains a wealth of quantitative data, which are hardly analysed in current routine clinical practice and this is now being transformed by radiomics. Mathematical analyses of these data using novel techniques, such as vascular morphometry (including vascular tortuosity and vascular volumes), blood flow imaging (including quantitative lung perfusion and computational flow dynamics), and artificial intelligence, are opening a window on the complex pathophysiology and structure-function relationships of pulmonary vascular diseases. They have the potential to make dramatic alterations to how clinicians investigate the pulmonary circulation, with the consequences of more rapid diagnosis and a reduction in the need for invasive procedures in the future. Applied to multimodality imaging, they can provide new information to improve disease characterization and increase diagnostic accuracy. These new technologies may be used as sophisticated biomarkers for risk prediction modelling of prognosis and for optimising the long-term management of pulmonary circulatory diseases. These innovative techniques will require evaluation in clinical trials and may in themselves serve as successful surrogate end points in trials in the years to come.

[Diagnostic Value of the Dual Source CT Dual Energy Pulmonary Perfusion Imaging for Pulmonary Embolism].

Objective To assess the diagnostic value of dual energy pulmonary perfusion imaging(DEPI)for pulmonary embolism.Methods The clinical data of 87 patients with suspected pulmonary embolism who had received DEPI between August 2017 and July 2018 in Jiaxing Second Hospital were retrospectively analyzed.With the findings of CT pulmonary angiography(CTPA)as the reference standard and with patients and pulmonary lobes as evaluation units,respectively,a diagnostic test was performed to calculate the diagnostic coincidence rate,sensitivity,specificity,positive predictive value,negative predictive value,Youden index,positive likelihood ratio,negative likelihood ratio,and Kappa coefficient value for the diagnosis of DEPI and CTPA.Results The coincidence rate,sensitivity,specificity,positive predictive value,negative predictive value,Youden index,positive likelihood ratio,and negative likelihood ratio were 85.06%,88.41%,72.22%,92.42%,61.90%,0.61,3.18,and 0.16,respectively,when applying the patients as evaluation units.When the pulmonary lobes were invoked as evaluation units,the above-mentioned indexes were 89.57%,76.80%,96.82%,93.20%,88.02%,0.74,24.15,and 0.24,respectively.The diagnostic results of DEPI and CTPA had a good and excellent consistency,respectively(Kappa value=0.571,0.765).Conclusions DEPI has high accuracy,sensitivity,and specificity in the detection of pulmonary embolism.The combination of DEPI with CTPA can simultaneously obtain the anatomical structure and functional information images,greatly improving the diagnostic accuracy for pulmonary embolism.Thus,it can be used as the preferred examination for patients with clinically suspected pulmonary embolism.

Value of dual-input perfusion of 320 row CT on the efficacy evaluation of small cell lung cancer / 肿瘤研究与临床

Objective To discuss the value of dual-input perfusion of 320 row CT on the efficacy evaluation of small cell lung cancer (SCLC).Methods A total of 18 patients with SCLC confirmed by pathology who received cisplatin plus etoposide chemotherapy between June 2016 and June 2018 in the 8th Medical Center of Chinese PLA General Hospital were collected.All patients received 320 row CT perfusion scan at 3 time points before chemotherapy,after 2 cycles and 4 cycles of chemotherapy.Tumor size,perfusion pseudo color map and bronchial arterial blood flow (BF),pulmonary flow (PF) and perfusion index (PI) were obtained.The efficacy and adverse reactions were evaluated.The single factor analysis was used to make the group comparison.Pearson test was used to make correlation analysis.Results Two patients after 2 cycles of chemotherapy had complete remission (CR),another 2 patients after 4 cycles of chemotherapy had CR,and 3 patients of the above 4 cases with CR had abundant BF;after 4 cycles of chemotherapy,7 cases had partial remission (PR),6 cases had stable disease (SD),1 patient had progression of disease (PD).Dual-input perfusion of 320 row CT showed that 10 cases had the tumor area ＜ 15 cm2 and 8 cased had the tumor area ＞15 cm2 before the treatment.There was a negative correlation between PI and the tumor area (r =-0.694,P =0.026) on patients with the tumor area ＜ 15 cm2 before the treatment,and no correlation was found in patients with tumor area ＞15 cm2 (P ＞ 0.05).One case had Ⅳ degree of bone marrow suppression,and obvious adverse reactions were not seen in the rest of the patients.Conclusion Dual-input perfusion of 320 row CT based on the simple imaging can make an accurate quantitative judgement of the effect of SCLC according to perfusion parameter,which provides a new basis for curative effect evaluation on SCLC.

Clinical research on combination of dose-volume histogram parameters with pulmonary perfusion imaging to predict the radiation pneumonitis / 肿瘤研究与临床

Objective To evaluate the lung exposure dose-volume (DVH) parameters and other indicators of lung perfusion imaging before and after three-dimensional conformal or intensity modulated radiation therapy for lung cancer patients,and combined with clinical factors,to explore relationship with radiation pneumonitis occurred.Methods 18 patients were selected for data analysis.Lung perfusion scintigraphy was detected before and after three-dimensional conformal or intensity modulated radiation therapy for lung cancer.Lung perfusion changes were compared before and after irradiation.Evaluation of radiation pneumonitis was assessed by the Radiation Therapy Oncology Group (RTOG) acute radiation pneumonitis standard.After the CT and SPECT lung perfusion images were transferred to Varian,the Eclipse 3D treatment planning system,image fusion after dose curve projected onto the SPECT images,and the DVH was converted into a f-DVH diagram.Analysis of pulmonary perfusion imaging changes before and after radiotherapy combined with lung irradiation dose volume parameters and radiation pneumonitis.Results In the whole group,33.3 ％ (6/18) cases occurred more than 2 radiation pneumonitis.Before and after radiotherapy,the damage to the lung perfusion was more than 2 radiation pneumonitis incidence [62.5 ％ (5/8)],and impaired pulmonary perfusion improvement was 10.0 ％ (1/10).DVH parameters to V5 severe RP forecasted high accuracy.In curve for each patient,boundary values of V5,V10 and V20 were 53 ％,41％ and 27 ％.Before and after radiotherapy it was found that lung perfusion changes and the whole lung V5 portfolio were the strongest predictors for radiation pneumonitis after radiotherapy.Conclusion Pulmonary perfusion imaging in patients with lung cancer is able to reflect changes in the function of ipsilateral lung perfusion before and after radiotherapy.Changes in the ipsilateral lung perfusion detected before and after radiotherapy combined with V5 are expected to serve as indicators to predict radiation pneumonitis.

Clinical Value of Radionuclide Pulmonary Perfusion Imaging in Diagnosing Acute Pulmonary Embolism / 实用放射学杂志

Objective To evaluate the clinical value of radionuclide pulmonary perfusion imaging in diagnosing acute pulmonary embolism.Methods Radioactive pulmonary perfusion imaging was performed in 25 patients clinically suspected for acute pulmonary embolism,meanwhile,imaging of deep veins of lower limb was taken.Results Multiple segments of abnormal blood perfusion were found in 23 of 25 patients,among them,radioactivity defects were found in 41 segments,radioactivity rarefied areas were found in 84 segments.Deep venous thrombosis was detected in 6 patients.Conclusion Radionuclide pulmonary perfusion imaging is a non-invasive and effective method in diagnosing acute pulmonary embolism.