Clinical Features and Outcomes of Pulmonary Artery Sarcoma.

OBJECTIVES: A retrospective cohort study was designed to describe the clinical features and outcomes of pulmonary artery sarcoma (PAS). METHODS: Twenty-two (22) consecutive patients diagnosed with PAS by pathological examination were enrolled and followed up until they died or until January 2020. The medical records were retrospectively reviewed to evaluate the clinical characteristics, image findings, and outcomes. RESULTS: 1) Twenty-one (21, 95.5%) patients were firstly misdiagnosed. Dyspnoea was the most common presenting symptom (19 of 22, 86.4%). 2) Filling defects in the right pulmonary artery were seen in 17 patients (77.3%) with computed tomography pulmonary angiography or magnetic resonance pulmonary angiography. Among those patients, 14 underwent positron emission tomography-computed tomography detection and 13 (92.9%) were found to have increased uptake value in the pulmonary artery. 3) The median survival (from diagnosis to death or January 2020) of the total series was 11.6 months (range, 0.7-68.5 months). The estimated cumulative survival rates at 1, 2, and 3 years were 52.6%, 32.8%, and 19.7%, respectively. Patients who received surgery and/or chemo-radiotherapy treatment had a better survival rate compared with patients without treatment (the estimated cumulative survival rates at 1, 2, and 3 years were 60.3%, 39.1%, and 29.3%, respectively, vs 33.3%, 16.6%, and 0, accordingly) and better survival time (median survival 17.02 vs 3.16 months, respectively) (p=0.025). CONCLUSIONS: Pulmonary artery sarcoma is easily misdiagnosed, as the symptoms and routine image detection are nonspecific. Positron emission tomography-computed tomography may be helpful in diagnosis. Surgery and/or chemo-radiotherapy offer a chance for better outcomes.

Differential Diagnosis of Pulmonary Artery Sarcoma and Central Chronic Pulmonary Thromboembolism Using CT and MR Images.

BACKGROUND: Clinical and imaging manifestations are similar in pulmonary artery sarcomas (PAS) and thromboembolic diseases, especially central chronic pulmonary thromboembolism (CPTE). The feasibility of utilising clinical imaging tools such as computed tomography (CT) and magnetic resonance imaging (MRI) for differential diagnosis of PAS and CPTE has not been fully explored, especially MRI. METHODS: Patients with PAS (n=18) and central CPTE (n=20) treated at our hospital between January 2013 and September 2016 were identified retrospectively. Computed tomography and MRI findings of pulmonary artery (PA) filling defects including the location, the involvement of pulmonary artery, morphology, signal intensities and enhancement in MRI, calcification, sizes of right atrium and ventricle, inner diameters of the pulmonary artery trunk and branches, and mediastinal collateral circulation in both groups were examined, and differences were analysed by Fisher exact test and independent sample t-test. RESULTS: Compared to those of central CPTE, PAS lesions were in full shape or expansive growth (p<0.001), and the proximal end of the tumours was often bulging or lobulated (p<0.001). These lesions were aneurysm- or grape-like distally (p<0.01) with inhomogeneous enhancement (p<0.001). The MRI contrast enhancement pattern of PAS lesions were cloudy with inhomogeneous delayed enhancement and the time-density curves for some of the lesions increased gradually. CONCLUSION: Computed tomographic and MR imaging manifestations may resemble PAS and central CPTE; however, some manifestations still have great value for the differential diagnosis of these two conditions, specifically the morphology and MRI enhancement patterns.

A Case of Pulmonary Hypertension Due to Fistulas Between Multiple Systemic Arteries and the Right Pulmonary Artery in an Adult Discovered for Occulted Dyspnoea.

BACKGROUND: Pulmonary hypertension (PH) can be caused by a fistula between the systemic and pulmonary arteries. Here, we report a case of PH due to multiple fistulas between systemic arteries and the right pulmonary artery where the ventilation/perfusion scan showed no perfusion in the right lung. METHODS: A 32-year-old male patient was hospitalised for community-acquired pneumonia. After treatment with antibiotics, the pneumonia was alleviated but dyspnoea persisted. Pulmonary hypertension was diagnosed using right heart catheterisation, which detected the mean pulmonary artery pressure as 37mmHg. The anomalies were confirmed by contrast-enhanced CT scan (CT pulmonary angiography), systemic arterial angiography and pulmonary angiography. RESULTS: Following embolisation of the largest fistula, the haemodynamics and oxygen dynamics did not improve, and even worsened to some extent. After supportive therapy including diuretics and oxygen, the patient's dyspnoea, WHO function class and right heart function by transthoracic echocardiography all improved during follow-up. CONCLUSIONS: Pulmonary hypertension can be present even when the right lung perfusion is lost. Closure of fistulas by embolisation, when those fistulas act as the proliferating vessels, may be harmful.

[Identification and classification of disease severity of wheat stripe rust using near infrared spectroscopy technology].

Wheat stripe rust caused by Puccinia striiformis f. sp. tritici, is an economically important disease in the world. It is of great significance to assess disease severity of wheat stripe rust quickly and accurately for monitoring and controlling the disease. In this study, wheat leaves infected with stripe rust pathogen under different severity levels were acquired through artificial inoculation in artificial climate chamber. Thirty wheat leaves with disease severity equal to 1%, 5%, 10%, 20%, 40%, 60%, 80% or 100% were picked out, respectively, and 30 healthy leaves were chosen as controls. A total of 270 wheat leaves were obtained and then their near infrared spectra were measured using MPA spectrometer. According to disease severity levels, 270 near infrared spectra were divided into 9 categories and each category included 30 spectra. From each category, 7 or 8 spectra were randomly chosen to make up the testing set that included 67 spectra. The remaining spectra were treated as the training set. A qualitative model for identification and classification of disease severity of wheat stripe rust was built using near infrared reflectance spectroscopy (NIRS) technology combined with discriminant partial least squares (DPLS). The effects of different preprocessing methods of obtained spectra, ratios between training sets and testing sets, and spectral ranges on qualitative recognition results of the model were investigated. The optimal model based on DPLS was built using cross verification method in the spectral region of 4000-9000 cm(-1) when "centralization" was used as the preprocessing method of spectra and the spectra were divided into the training set and the testing set with the ratio equal to 3:1. Accuracy rate of the training set was 95.57% and accuracy rate of the testing set was 97.01%. The results showed that good recognition performance could be acquired using the model based on DPLS. The results indicated that the method using near infrared reflectance spectroscopy technology proposed in this study is feasible for identification and classification of disease severity of wheat stripe rust. A new method was provided for monitoring and assessment of wheat stripe rust.

[Detection of Puccinia strii formis f. sp. tritici latent infections in wheat leaves using near infrared spectroscopy technology].

To realize the early detection of P. strii formis f. sp. tritici latent infections in wheat leaves while no disease symptoms appear, a qualitative model for identification of the wheat leaves in the incubation period of stripe rust was built using near infrared reflectance spectroscopy (NIRS) technology combined with qualitative partial least squares (DPLS). In this study, 30 leaf samples infected with P. strii formis f. sp. tritici were collected each day during the eleven-day incubation period. And 30 healthy leaf samples and 30 leaf samples showing disease symptoms infected with P. strii formis f. sp. tritici, were also collected as controls. In total, there were 390 leaf samples that were divided into thirteen categories. Near infrared spectra of 390 leaf samples were obtained using MPA spectrometer and then a model to identify the categories of wheat leaves was built using cross verification method. The effects of different spectral ranges, samples for building the model, preprocessing methods of spectra and number of principal components on NIRS prediction results for qualitative identification were investigated. The optimal identification results were obtained for the model built in the combined spectral region of 5 400-6 600 and 7 600-8 900 cm(-1) when the spectra were divided into the training set and the testing set with the ratio equal to 4 : 1, "scatter correction" was used as the preprocessing method and the number of principal components was 14. Accuracy rate, misjudgment rate and confusion rate of the training set were 95.51%, 1.28% and 3.21%, respectively. And accuracy rate, misjudgment rate and confusion rate of the testing set were 100.00%, 0.00% and 0.00%, respectively. The result showed that using near infrared reflectance spectroscopy technology, P. strii formis f. sp. tritici latent infections in wheat leaves could be detected as early as one day after inoculation (or 11 days before symptoms appearing) and the number of days when the leaf has been infected could also be identified. The results indicated that the method using near infrared reflectance spectroscopy technology proposed in this study is feasible for the identification of wheat leaves latently infected by P. strii formis f. sp. tritici. A new method based on NIRS was provided for the early detection of wheat stripe rust in this study.

[Application of near infrared spectroscopy to qualitative identification and quantitative determination of Puccinia strii formis f. sp. tritici and P. recondita f. sp. tritici].

To realize qualitative identification and quantitative determination of Puccinia strii formis f. sp. tritici (Pst) and P. recondita f. sp. tritici (Prt), a qualitative identification model was built using near infrared reflectance spectroscopy (NIRS) combined with distinguished partial least squares (DPLS), and a quantitative determination model was built using NIRS combined with quantitative partial least squares (QPLS). In this study, 100 pure samples including 50 samples of Pst and 50 samples of Prt were obtained, and 120 mixed samples including three replicates of mixed urediospores of the two kinds of pathogen in different proportions (the content of Pst was within the range of 2. 5% 100% with 2. 5% as the gradient) were obtained. Then the spectra of the samples were collected using MPA spectrometer, respectively. Both pure samples and mixed samples were divided into training set and testing set with the ratio equal to 2:1. Qualitative identification model and quantitative determination model were built using internal cross-validation method in the spectral region 4,000--10,000 cm(-1) based on the training sets from pure samples and mixed samples, respectively. The results showed that the identification rates of the Pst-Prt qualitative identification model for training set and testing set were both up to 100. 00% when scatter correction was used as the preprocessing method of the spectra and the number of principal components was 3. When 'range normalization + scatter correction' was used as the preprocessing method of the spectra and the number of principal components was 6, determination coefficient (RZ), standard error of calibration (SEC) and average absolute relative deviation(AARD) of the Pst-Prt quantitative determination model for training set were 99.36%, 2.31% and 8.94%, respectively, and R2, standard error of prediction (SEP) and AARD for testing set were 99.37%, 2.29% and 5. 0%, respectively. The results indicated that qualitative identification and quantitative determination of Pst and Prt using near infrared spectroscopy technology are feasible and that the Pst-Prt qualitative identification model and the Pst-Prt quantitative determination model built in this study were reliable and stable. A new method based on NIRS was provided for qualitative identification and quantitative determination of plant pathogen in this study.

[Early diagnosis of wheat stripe rust and wheat leaf rust using near infrared spectroscopy].

In the present study, near-infrared reflectance spectroscopy (NIRS) technology was applied to implement early diagnosis of two kinds of wheat rusts, i. e. wheat stripe rust and wheat leaf rust, by detecting wheat leaves as disease symptom has not appeared. The wheat leaves were divided into five categories including healthy leaves, leaves in the incubation period infected with P. strii formis f. sp. tritici, leaves showing symptom infected with P. strii formis f. sp. tritici, leaves in the incubation period infected with P. recondita f. sp. tritici and leaves showing symptom infected with P. recondita f. sp. tritici. Near infrared spectra of 150 wheat leaves were obtained using MPA spectrometer and then a model to identify the categories of wheat leaves was built using distinguished partial least squares (DPLS). For building the model, second-order derivative method was regarded as the best preprocessing method of the spectra and the spectral region 4000 - 8000 cm(-1) was regarded as the optimal spectral region. Using the model with different training sets and testing sets, the average identification rate of the training sets was 96.56% and the average identification rate of the testing sets was 91.85%. The results proved the model's stability. The optimal identification rates were obtained while the ratio of training set to testing set was 2 : 1 and the number of principal components was 10. The identification rate of the training set was 97.00% and the identification rate of the testing set was 96.00%. The results indicated that the identification method based on the NIRS technology developed in this study is feasible for early diagnosis of wheat stripe rust and wheat leaf rust.

[Relationship between spinal ventricular septal angle by computer tomographic pulmonary angiography and right cardiac functions, N-terminal brain natriuretic peptide in chronic thromboembolic pulmonary hypertension].

OBJECTIVE: To explore the relationship of spinal ventricular septal angle (SVSA) measured by computer tomographic pulmonary angiography (CTPA) and right cardiac functions, N-terminal brain natriuretic peptide (NT-proBNP) in the patients with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Forty-four CTEPH patients, 26 males and 18 females aged (52 ± 12) years old on average, at our hospital from January 2008 to January 2010 were retrospectively reviewed. SVSA and such pulmonary artery obstruction indices as Qanadli and Mastora indices were evaluated by two independent radiologists. The parameters of right heart functions were evaluated by echocardiography and right-heart catheterization. The level of NT-proBNP was measured by enzyme linked immunosorbent assay (ELISA). RESULTS: SVSA was (63 ± 11)° in CTEPH and (40 ± 7)° in the control group. The differences were significant (t = 12.320, P = 0.000). SVSA had a moderately positive correlation with the level of NT-proBNP (r = 0.704, P = 0.000). A positive correlation existed between SVSA and right atrium transverse diameter (r = 0.381, P = 0.002), right atrium long axis diameter (r = 0.437, P = 0.000) and right ventricular transverse diameter (r = 0.449, P = 0.000) on echocardiography. But there was no correlation between SVSA and right ventricular ejection fraction (r = -0.175, P = 0.365, n = 24). Also there was a negative correlation between SVSA and cardiac output (r = -0.337, P = 0.025), cardiac index (r = -0.351, P = 0.020), right cardiac work (r = -0.307, P = 0.043) and right ventricular stroke work (r = -0.384, P = 0.010). CONCLUSION: Spinal ventricular septal angle measured on CTPA may serve as a better predictor for evaluating the level of NT-proBNP and right cardiac functions in CTEPH.

Value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of pulmonary artery activity in patients with Takayasu's arteritis.

AIMS: To explore the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of active pulmonary artery (PA) lesions in patients with Takayasu's arteritis (TA). METHODS AND RESULTS: Consecutive TA patients with PA involvement were prospectively recruited. Clinical activity was assessed according to the National Institutes of Health (NIH) criteria. CT pulmonary angiography (CTPA) or magnetic resonance pulmonary angiography was performed for evaluation of vascular structural characteristics, and mural thickening was considered as radiologically active. A vascular segment with 18F-FDG uptake ≥ liver was considered as PET-active. A total of 38 18F-FDG PET/CT scans were performed in 29 patients. In terms of disease activity, the sensitivity of 18F-FDG PET/CT did not significantly differ from radiological imaging (71.4% vs. 92.9%, P = 0.250), but 18F-FDG PET/CT had higher specificity (91.7% vs. 37.5%, P = 0.001) and accuracy (84.2% vs. 57.9%, P = 0.022). Although the majority of PET-active PA segments (54.9%) showed mural thickening, 14 PA segments with normal structure were also PET-active. 18F-FDG activity did not significantly differ between the PA and aorta in clinically active patients. In addition, 18F-FDG activity of the PA was positively correlated with inflammatory markers. Changes in 18F-FDG activity in PA during follow-up reflected therapeutic effects. CONCLUSION: 18F-FDG PET/CT can effectively evaluate PA activity in TA patients, and its diagnostic performance is superior to radiological imaging. The 18F-FDG activity of PA shows a good correlation with clinical disease status and inflammatory markers and can be used to monitor therapeutic effects.

[The acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension].

OBJECTIVE: To evaluate the acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: A prospective study was made. Eighteen patients with CTEPH were enrolled. At right heart catheterisation, iloprost was inhaled at 20 microg for 10 - 15 min. Compare the value of heart rate (HR), mean blood pressure (mBP), mean pulmonary arterial hypertension (mPAP), right atrium pressure (RAP), pulmonary arterial wedge pressure (PAWP), cardiac output (CO), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), arterial partial pressure of oxygen (PaO2), arterial oxygen saturation (SaO2), mixed venous saturation (SvO2), pulmonary shunt fraction (Qs/Qt), alveolar-arterial partial pressure of oxygen [P ( A-a) O2] before to after inhaled iloprost in these patients. RESULTS: Significant changes (before to after inhalation): mPAP, (53 +/- 11) to (47 +/- 14) mm Hg (P < 0.01); PVR, (821 +/- 194) to (681 +/- 199) dyn x s x cm(-5) (P < 0.01); RAP, (10 +/- 6) to (7 +/- 6) mm Hg (P < 0.01). However, HR, PAWP, mBP, CO and SVR had no significant changes. At the same time, inhaled iloprost significantly decreased PaO2 from (58 +/- 11) to (52 +/- 6) mm Hg (P < 0.01) and increased Qs/Qt from (27 +/- 11)% to (33 +/- 9)% (P < 0.01)and P(A-a) O2 from (86 +/-39) to (93 +/- 38) mm Hg (P < 0.01). CONCLUSION: Inhaled iloprost might instantly improve hemodynamics in CTEPH, but at the same time it increased arteriovenous shunts which resulted in lower PaO2.

[The oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension].

OBJECTIVE: To study the acute oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension. METHODS: Twenty-two and 24 patients who were admitted to our hospital between June 2006 and January 2009 with confirmed diagnosis of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) respectively were enrolled to this study. During right heart catheterization, the hemodynamics and oxygen kinetics were monitored at baseline and after inhaling Iloprost (20 micrograms). RESULTS: At baseline, the arterial partial pressure of oxygen (PaO2) was (63 +/- 10) mm Hg (1 mm Hg = 0.133 kPa) and (59 +/- 10) mm Hg respectively in PAH and CTEPH patients, and the oxygen delivery index (DO2I) and oxygen consumption index (VO2I) were (458 +/- 136) ml x min(-1) x m(-2) and (135 +/- 53) ml x min(-1) x m(-2) in PAH patients respectively, and (386 +/- 92) ml x min(-1) x m(-2) and (131 +/- 43) ml x min(-1) x m(-2) in CTEPH patients respectively. Three minutes after inhaling Iloprost, for PAH and CTEPH patients, the pulmonary shunt rate (Qs/Qt) all increased significantly (all P < 0.05, respectively) as well as the difference of oxygen partial pressure between pulmonary alveoli and artery (P[A-a]O2, all P < 0.05, respectively), and the arterial oxygen content (CaO2) all decreased significantly (all P < 0.05, respectively). The oxygenation parameters of mixed venous blood, oxygen extractive rate and DO2I did not change significantly, but VO2I declined to different extent. The extent of change after inhaling Iloprost for all oxygen kinetic parameters were similar between PAH and CTEPH patients. At baseline, mixed venous oxygen saturation (SvO2), venous oxygen content (CvO2) and DO2I in CTEPH patients were lower than those in PAH patients. After inhaling Iloprost, in CTEPH patients, PaO2, SvO2 and CvO2 were lower than those in PAH patients. CONCLUSION: There were hypoxemia and abnormality of oxygen kinetics in PAH and CTEPH patients. After inhaling Iloprost, pulmonary shunt increased without improvement in oxygen kinetics. Oxygenation should be monitored closely and supply oxygen supplied for CTEPH when inhaling Iloprost.

[Disease index inversion of wheat stripe rust on different wheat varieties with hyperspectral remote sensing].

It is becoming more and more important to use mixed wheat varieties to control wheat stripe rust. Different wheat varieties were planted in field and stripe rust was caused by artificial inoculation. Disease index (DI) was assessed and the canopy reflection data of wheat canopy were obtained by ASD FieldSpec HandHeld FR(325-1 075 nm) made by ASD Company. The correlation analysis between DI and spectral data (reflectance and the first derivative) was conducted, and the estimation models between DI and reflection data (reflectance at 690 and 850 nm, SDr, NDVI and RVI) were built using linear regression method. The results showed that different combinations of wheat varieties had the similar variation at different disease index. DI has positive correlation with reflectance of wheat canopy in visible region, and has significant negative correlation in the near infrared region. DI has stable negative correlation with the first derivative in the region of 700-760 nm and with big fluctuation in other regions. The correlation was compared between DI and hyperspectral derivative index, and SDr has the best correlation with DI. DI estimation models were built based on the canopy reflectance at 690 and 850 nm, SDr, NDVI and RVI. The determinant coefficient of the models is between 0.588 and 0.855, 0.669 and 0.911, 0.534 and 0.773, and 0.587 and 0.751, respectively, and all the models were fit well. The results indicated that DI of wheat stripe rust could be inverted using hyperspectral remote sensing technique and that the inversion effect was hardly influenced by the different combinations of wheat varieties.

[Application of hyperspectral data to the classification and identification of severity of wheat stripe rust].

Wheat stripe rust, caused by Puccinia strii formis f. sp. tritici, is one of pandemic diseases causing severe losses in China. Monitoring and warning of this disease is principal for its precise prediction and for implementing effective measures to control it. The hyperspectral data used for analysis were attained from 88 leaves including healthy leaves and infected leaves over a range of disease severity levels. Support vector machine (SVM) was applied to classify and identify the severity of wheat leaves infected by the pathogen. The model was built based on 44 proof-read samples to estimate 44 proof-test samples. And the identification accuracy is totally 97%. So SVM can be used in the classification and identification of severity of wheat stripe rust based on attained hyperspectral data.

[The clinical application of electron beam tomography in the diagnosis of pulmonary thromboembolism].

OBJECTIVE: To evaluate the clinical significance of electron beam computerized tomography (EBCT) in the diagnosis and differential diagnosis of pulmonary thromboembolism (PTE). METHODS: EBCT was performed before March 2004 in 114 consecutive patients with clinically suspected pulmonary vascular diseases, including 76 patients with PTE, 29 with pulmonary arteritis, 5 with primary pulmonary arterial tumor, and 4 with pulmonary arterial invasion by lung or mediastinal carcinoma. EBCT was performed using Imatron C-150 scanner with enhanced continuum volume scan (CVS). The slice thickness was 3 mm with scanning time of 0.1 s. The total amount of contrast media (Omnipaque-300) used was 50-100 ml, with flow rates of 3.0-4.0 ml/s and a delay time of 14-25 s. RESULTS: Deep venous thrombosis (DVT) was confirmed in 58 (76.3%) of the 76 patients with PTE (52 men and 24 women), 8 (10.6%) of them without apparent causes. Of the 2 356 pulmonary arterial branches observed in the 76 cases, 1,668 branches (70.8%) showed signs of PTE, with 545 branches (32.7%) of the central pulmonary arteries and 1 123 branches (67.3%) of the peripheral pulmonary arteries. Central type filling defect, such as the "railway sign" or the "drifting sign", was specific for acute thrombosis. Thrombus calcification was a specific sign of chronic PTE. Indirect signs of PTE included mosaic signs, enlargement of the right ventricle and atrium, pulmonary artery enlargement, pulmonary infarction, pericardial and/or pleural effusion, pulmonary atelectasis and pulmonary consolidation. Pulmonary arteritis (including pulmonary arterial involvement in Takayasu arteritis) was diagnosed by EBCT in 27 (93.1%) of the 29 patients, in which the diagnosis was confirmed by pulmonary angiography in 16, and clinically in 13 Patients. Of the 5 patients with primary pulmonary arterial tumor confirmed by pathology, 1 was misdiagnosed by EBCT. Of the 4 patients with pulmonary arterial involvement by lung or mediastinal carcinoma, 3 were confirmed by surgery and 1 by pulmonary angiography. CONCLUSIONS: DVT and PTE are different manifestations of one disease. The diagnostic strategy aims to detect thrombosis in the pulmonary arteries and in the deep veins of the lower limbs at the same time. EBCT is an effective and non-invasive examination in the diagnosis and differential diagnosis of PTE. By EBCT, acute and chronic thrombi can be initially differentiated, and changes in lung parenchyma, mediastinum, and the pulmonary and systemic arterial walls can be observed, and therefore more valuable radiological information can be collected for clinical decision-making.

A septal angle measured on computed tomographic pulmonary angiography can noninvasively estimate pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension.

PURPOSE: To explore the correlation between a septal angle measured on computed tomographic pulmonary angiography (CTPA) and pulmonary vascular resistance (PVR) determined by right heart catheterization in patients with chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS: Eighty-six patients with CTEPH (54 men, mean age: 53.08±12.43 y) were retrospectively reviewed, and 86 sex-matched and age-matched individuals without pulmonary artery hypertension and pulmonary embolism were used as the control group. All patients with CTEPH underwent CTPA before right heart catheterization. Septal angle was measured on transverse CTPA images as the angle between the interventricular septum and the line joining the midpoint of the sternum to the thoracic vertebral spinous process. Hemodynamic PVR was calculated on the basis of the data from right heart catheterization. RESULTS: Septal angle was 65.27±12.24 degrees and 39.43±9.79 degrees in the CTEPH group and control group, respectively, which was statistically significant (t=18.139, P=0.000). The septal angle correlated positively with PVR (r=0.629, P=0.000). By stepwise linear regression analysis, the septal angle was shown to be the only variable (r=0.578) that was independently associated with PVR levels, leading to the following equation: PVR=21.591×septal angle-374.641. By receiver operating characteristic analysis, septal angle ≥67.55 degrees had a sensitivity of 71.6% and a specificity of 73.4% for predicting PVR≥1000 dyne s/cm with an area under the curve of 0.739±0.055, which was higher than the area under the curve of right ventricular area/left ventricular area (0.627±0.061) and that of transverse diameter of right ventricle/transverse diameter of left ventricle (0.612±0.060). CONCLUSION: The septal angle is a useful tool for estimating PVR in patients with CTEPH.