Digital Subtraction Pulmonary Angiography Research Articles

Noninvasive optical monitoring of pulmonary embolism: a Monte Carlo study on visible Chinese human thoracic tissues.

In recent years, the incidence rate of pulmonary embolism (PE) has increased dramatically. Currently, the correct diagnosis rate of PE in China is relatively low, and the diagnosis error rate and missed diagnosis rate were as high as about 80%. The most standard method of PE detection is pulmonary artery digital subtraction angiography (DSA), but pulmonary artery DSA is an invasive examination, and patients can have certain risks and discomfort. Noninvasive monitoring of PE remains challenging in cardiovascular medicine. We attempt to study the light propagation in human thoracic tissues and explore the possibility of near-infrared spectroscopy (NIRS) in noninvasive detection of PE. In this study, by utilizing the Monte Carlo simulation method for voxelized media and the Visible Chinese Human dataset, we quantified and visualized the photon migration in human thoracic region. The influence of the development (three levels) of PE on the light migration was observed. Results showed that around 4.6% light fluence was absorbed by the pulmonary tissue. The maximum signal sensitivity distribution reached 0.073% at the 2.8- to 3.1-cm light source-detector separation. The normalized light intensity was significantly different among different PE levels and formed a linear relationship ( , ). The study found that photons could reach the pulmonary artery tissue, the light intensity was linearly related to the degrees of embolism, PE could be quantitatively diagnosed by NIRS. Meanwhile, the optimized distance in between the light source and detector, 2.8 to 3.1cm, was recommended to be used in future potential noninvasive optical diagnosis of PE.

Cyanosis in a Previously Well Child.

Cyanosis in a Previously Well Child.

Applicability of Transthoracic Contrast Echocardiography for the Diagnosis and Treatment of Idiopathic Pulmonary Arteriovenous Malformations.

Objective: To explore the preferred test to screen for pulmonary arteriovenous malformations (PAVMs) and to predict the probability of interventional embolization.Methods: We performed a retrospective observational study evaluating patients with idiopathic PAVMs from 2009 to 2019. After clinical evaluation, a total of 105 patients were studied, including 71 patients with positive digital subtraction pulmonary angiography (DSPA) findings and 34 with negative DSPA findings. The following patient data were assessed: blood test, chest radiograph, transthoracic contrast echocardiography (TTCE), and DSPA findings.Results: The majority of patients with idiopathic PAVMs were female (66.2% with positive DSPA findings). We found a good κ-coefficient of 0.77 with strong consistency for inter observer agreement concerning the pulmonary right-to-left shunt (RLS) grade on TTCE, which was superior to conventional chest radiographs. The positive predictive value (PPV) of the radiographic features for PAVMs on DSPA was 0.83 (95% CI 0.64–1.0) and 0.44 for the possibility of embolization (95% CI 0.19–0.70). The PPV of the shunt grade of PAVMs on DSPA was 0.14 (95% CI 0.01–0.29) for grade 1, 0.74 (95% CI 0.60–0.88) for grade 2, and 0.97 (95% CI 0.92–1.0) for grade 3. The PPVs of pulmonary shunt grades 2 and 3 on TTCE for the possibility of embolization for PAVMs were 0.21 (95% CI, 0.05–0.36) and 0.87 (95% CI, 0.79–0.99), respectively.Conclusion: TTCE is the preferred screening test for PAVMs. The pulmonary RLS grade on TTCE not only identifies the likelihood of PAVMs but also predicts the probability for embolization.

Ventilation-Perfusion Scan Is Superior to CT Pulmonary Angiography in Detection of Chronic Thromboembolic Pulmonary Hypertension in SCD Adults

▪Background: Pulmonary hypertension (PH) in adults with sickle cell disease (SCD) is associated with significant morbidity and early mortality. Venous thromboembolism (VTE) is common in SCD and affects about 25% of SCD adults. Although not generally considered a major cause of PH, chronic thromboembolic pulmonary hypertension (CTEPH) has been noted, and is probably more common than realized in patients with SCD. National guidelines recommend that CTEPH should be excluded in any patient suspected to have PH. Imaging techniques, including ventilation-perfusion (V/Q) scintigraphy, multidetector CT pulmonary angiography (CTPA), high-resolution CT (HRCT), pulmonary digital subtraction angiography (DSA), and magnetic resonance angiography have been used in identifying CTEPH as the cause of PH. Several studies have shown that V/Q scintigraphy is able to distinguish patients with CTEPH from other causes of PH, to the extent that normal V/Q scintigraphy can comfortably rule out CTEPH. However, data on V/Q and associated outcomes on SCD are limited. In this study, we report a retrospective analysis of V/Q scintigraphy findings and CTPA for assessing PH as validated by right heart catherization. We also report associated outcomes of the V/Q findings with prospectively collected data in the adult SCD patients.Methods: This study was approved by the Institutional Review Board at the National Institutes of Health (NIH), and all subjects provided written informed consent to one or more studies.A total of 142 consecutive patients, (83 women, aged 40.1 ± 13.7 years, HbSS 124 (87%) suspected of having PH were prospectively enrolled (Table 1). All patients underwent V/Q scanning, echocardiography (ECHO), six-minute walk testing (6MWT); 52 patients underwent CTPA, and 63 patients had right heart catheterization (RHC) performed. Interpretation of V/Q images was based on the refined Pulmonary Embolism Diagnosis criteria. High-probability and intermediate-probability V/Q scan findings were considered to be positive or abnormal, and very low, low-probability/normal V/Q scan findings were considered negative or normal V/Q.Results: V/Q scan was abnormal in 58 (40.8%) patients (high probability and intermediate probability in 26 (18.3%), 32 (22.5%), respectively), and was low probability/normal in 84 (59.2%) patients (Table 1). CTPA was positive for PE in 17 (32.7%) patients. Patients with positive CTPA were more likely to have abnormal V/Q [ abnormal V/Q 14 (82.4%) vs. normal V/Q 3(17.6); p=0.032], but in those with negative CTPA (n=35), V/Q was abnormal in 18 (51.4%) (Table 2). RHC confirmed PH (mean pulmonary artery pressure (mPAP) ≥25mmHg) in 45/63 patients, of which 33 (73.3%) had abnormal V/Q compared to 12 (26.6%) with normal V/Q scans, (p=0.0001). Among those with no PH by RHC (n=18), only one patient showed abnormal and 17 normal V/Q (5.6% vs 94.4%, respectively, (p<0.001). Thirty-two patients had a complete dataset of V/Q, CTPA and RHC, and clearly there was greater concordance of results between RHC with V/Q than CTPA (Table 3). Subjects with SCD and abnormal V/Q demonstrated significantly worse hemodynamic severity (mPAP=35.95 ± 9.20 vs.24.8± 12.09 mmHg, p<0.001; right atrial pressure= 9.59± 4.53 vs. 9.59± 4.53mmHg, p<0.001; transpulmonary gradient 21.8 ± 10.4 vs. 12.16± 11mmHg, p=0.001, and pulmonary vascular resistance=238.3 ± 135 vs.120.5 ± 134.9 dynes.s.cm-5, p=0.001 ) and abnormal cardiopulmonary markers of clinical severity compared to those with a normal V/Q group, including higher TRV (3.5±0.6 vs. 3±0.5 m/s, p=0.01) and poor exercise capacity (6MWD 379.7±117.3 vs. 438.8±115.5m, p<0.001). Over a median follow-up of 6 years with a maximum follow-up of 15 years, total of 34 deaths were observed (Fig 1). The all-cause mortality was higher in the abnormal V/Q 19 (56%) group compared to those with normal V/Q 15 (44%) patients (log-rank test, p<0.001, Hazard Ratio=2.54).Conclusion: Using RHC as the benchmark, our data demonstrates that V/Q scan is superior in detecting CTEPH in adults with SCD. Additionally, abnormal V/Q scan is associated with worse hemodynamics by RHC, poor functional capacity and increased mortality. We recommend frequent use of V/Q in the evaluation of dyspnea in adults with SCD as confirmation of CTEPH has important implications in management. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comparison of V/Q SPECT and CT Angiography for the Diagnosis of Chronic Thromboembolic Pulmonary Hypertension

Background Accurate methods for identifying obstructions in both large and small vessels are crucial for diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). Purpose To compare the performance of ventilation-perfusion (V/Q) scanning, V/Q SPECT, and CT pulmonary angiography (PA) in CTEPH by using digital subtraction PA as the reference standard. Materials and Methods This prospective study was conducted from January 2016 to January 2018. A total of 229 participants suspected of having CTEPH were evaluated with V/Q SPECT, V/Q planar scintigraphy, CT PA, and digital subtraction PA. Participants underwent all four procedures within 1 week. Differences in the diagnostic performance of V/Q SPECT, V/Q planar scintigraphy, and CT PA were evaluated with areas under the curve receiver operator curve, the McNemar test, and generalized estimating equations analysis. Results A total of 150 participants (mean age, 42 years ± 15 [standard deviation]; 99 women) were enrolled. Digital subtraction PA assessments confirmed CTEPH in 51 participants and indicated that 602 of 1020 lung segments (20 segments per participant) were obstructed. The three imaging methods showed high sensitivity (V/Q SPECT, 98%; V/Q planar scintigraphy, 98%; CT PA, 94%) and specificity (V/Q SPECT, 89%; V/Q planar scintigraphy, 91%; CT PA, 96%) (all P > .05). However, both V/Q scanning techniques were more sensitive (V/Q SPECT: 85%, P < .001 vs CT PA: 67%; V/Q planar scintigraphy: 83%, P < .001 vs CT PA: 67%), and less specific (V/Q planar scintigraphy: 51%, P = .03 vs CT PA: 60%; V/Q SPECT: 42%, P < .01 vs CT PA: 60%) than was CT PA for segmental analysis. Areas under the curve for CT PA, V/Q planar scintigraphy, and V/Q SPECT were 0.95, 0.95, and 0.94, respectively (all P > .05), for individual analysis, and 0.64, 0.67, and 0.64, respectively, by segment (V/Q planar scintigraphy vs V/Q SPECT, P = .02; V/Q planar scintigraphy vs CT PA, P = .08; V/Q SPECT vs CT PA, P = .94). Conclusion Ventilation-perfusion scanning was more sensitive and less specific than was CT pulmonary angiography for detecting vascular obstructions at the segmental pulmonary arterial level. © RSNA, 2020 See also the editorial by Swift and Rajaram in this issue.

Pulmonary Vascular Underperfusion Score in Premature Infants with Bronchopulmonary Dysplasia and Pulmonary Hypertension.

Pulmonary hypertension (PH) is a complication of bronchopulmonary dysplasia (BPD). The underlying pathophysiology of BPD-associated PH is complex and poorly understood. Echocardiogram may underestimate the severity of pulmonary hypertensive vascular disease in severe BPD. Digital subtraction pulmonary angiography (DSPA) is a potentially useful imaging modality for evaluating changes in the pulmonary vasculature of BPD-associated PH. In this study, we objectively quantified the pulmonary hypertensive vascular changes demonstrated by DSPA using a novel pulmonary vascular underperfusion score (PVUS) and correlated the scoring system with echocardiography parameters and cardiac hemodynamics by right heart catheterization.

Digital Subtraction Pulmonary Angiography in Children with Pulmonary Hypertension due to Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is the most common respiratory sequelae of prematurity and histopathologically features fewer, dysmorphic, pulmonary arteries. We present our experience with the digital subtraction pulmonary angiography (DSPA) findings of a segmental vascular filling abnormality in three children who were born at extreme prematurity and have pulmonary hypertension due to severe BPD. Our preliminary data suggest that DSPA may be useful in evaluating the severity of pulmonary vascular disease in children with BPD.

Role of 320-Slice CT Imaging in the Diagnostic Workup of Patients With Chronic Thromboembolic Pulmonary Hypertension

Right-sided heart catheterization (RHC) and pulmonary digital subtraction angiography (PDSA) are the standard methods used in diagnosing suspected or defi nite chronic thromboembolic pulmonary hypertension (CTEPH). We studied the ability of 320-slice CT imaging to detect simultaneously chronic thromboembolic fi ndings in the pulmonary arteries and pulmonary hemodynamics based on the curvature of the interventricular septum (IVS) in CTEPH . Forty-four patients with high clinical suspicion of CTEPH underwent RHC, PDSA, and enhanced double-volume retrospective ECG-gated 320-slice CT scan. We measured the sensitivity and specificity of CT imaging to detect thrombi in the pulmonary arteries compared with PDSA. We also compared IVS bowing (expressed as curvature) measured on the short-axis cine heart image with pulmonary arterial pressure (PAP) obtained by RHC. Compared with PDSA, the sensitivity and specificity of CT imaging to detect chronic thromboembolic findings were 97.0% and 97.1% at the main/lobar level and 85.8% and 94.6% at the segmental level, respectively. The correlation coefficients of IVS curvature with systolic PAP and mean PAP were 2 0.79 ( P , .001) and 2 0.86 ( P , .001), respectively. The use of 320-slice CT imaging allows for less invasive and simultaneous detection of thrombi and evaluation of pulmonary hemodynamics for the diagnostic work-up of CTEPH.

Computed tomographic pulmonary angiography in the assessment of severity of chronic thromboembolic pulmonary hypertension and right ventricular dysfunction

The aim was to investigate the role of computed tomographic pulmonary angiography (CTPA) in the assessment of severity and right ventricular function in chronic thromboembolic pulmonary hypertension (CTEPH). Clinical and radiological data of 56 patients with CTEPH January 2006-October 2009 were retrospectively reviewed in the present study. All patients received CTPA with a 64-row CT using the retrospective ECG-Gated mode before digital subtraction pulmonary angiography and right-heart catheterization. CTPA findings including Right Ventricular diameter (RVd) and left ventricular diameter (LVd) were measured at the end diastole. CT Pulmonary Artery Obstruction Indexes including Qanadli Index and Mastora Index were used in the assessment of severity of pulmonary arterial obstruction. Hemodynamic parameters and pulmonary hypertension classification were evaluated by right-heart catheterization in all patients. Right ventricular function was measured with echocardiography in 49 patients. Qanadli Index and Mastora Index respectively were (37.93±14.74)% and (30.92±16.91)%, which showed a significant difference (Z=-5.983, P=0.000) and a good correlation (r=0.881, P=0.000). Neither Qanadli nor Mastora Index correlated with pulmonary hypertension classification (r=-0.009, P=0.920) or New York Heart Association heart function classification (r=-0.031, P=0.756). Neither Qanadli nor Mastora Index correlated with any echocardiographic right ventricular parameters (P>0.05), while RVd/LVd by CTPA correlated with echocardiographic right ventricular functional parameters (P<0.05). Both Qanadli (r=-0.288, P=0.006) and Mastora Index (r=-0.203, P=0.032) demonstrated a weakly negative correlation with SPO2. CTPA findings correlated with hemodynamic variables. Backward linear regression analysis revealed that the RVd/LVd, Right Ventricular Anterior Wall Thickness (RVAWT), Main Pulmonary Artery trunk diameter (MPAd) were shown to be independently associated with mean Pulmonary Artery Pressure (mPAP) levels (model: r2=0.351, P=0.025; RVd/LVd: beta=11.812, P=0.000; RVAWT: beta=2.426, P=0.000; MPAd: beta=0.677, P=0.003). Computed tomographic pulmonary angiography is a valuable tool to evaluate hemodynamics, right ventricular function of CTEPH, but neither Qanadli Index nor Mastora Index can reflect pulmonary arterial obstruction in CTEPH accurately.

Imaging of the pulmonary arteries

For decades, classical pulmonary digital subtraction angiography (DSA) has served as the gold standard for the direct assessment of the pulmonary vasculature. During the past decade, substantial advances have been achieved in all cross-sectional imaging modalities in terms of spatial and temporal resolution. As a consequence of that, computed tomography angiography (CTA) and magnetic resonance imaging (MRI) are the modalities of choice for the morphological (CTA) and functional (MRI) assessment and will be presented in the context of the technical developments (CT: from single-slice scanners to modern multi-slice equipment, including latest innovations such as 320-slice CT and flash technology; MR: 1.5T vs. 3.0T, parallel imaging, time-resolved MR angiographic secquences, as well as perfusion MR imaging). Dedicated contrast media delivery protocols are a prerequisite for optimal results.

Hemodynamic Effects of Monomeric Nonionic Contrast Media in Pulmonary Angiography in Chronic Thromboembolic Pulmonary Hypertension

The purpose of this study was to investigate the hemodynamic safety of the monomeric nonionic contrast agent iomeprol for selective pulmonary angiography in chronic thromboembolic pulmonary hypertension (CTPH), and to investigate the effect of periinterventional oxygen administration. Selective pulmonary digital subtraction angiography was performed in 94 patients with CTPH using six bolus injections of iomeprol (posteroanterior, oblique, and lateral projections; both pulmonary arteries; iomeprol, 25 mL at 13 mL/s). Hemodynamics were obtained with Swan-Ganz catheters, and systolic pulmonary artery pressure (PAsyst) was classified into one of three groups: 30 mm Hg or less (control group), greater than 30 but less than or equal to 60 mm Hg (group 1, moderate pulmonary hypertension), and greater than 60 mm Hg (group 2, severe pulmonary hypertension). At baseline, values for PAsyst were 21.4 +/- 2.3 (control group, n = 8), 49.8+/- 8.5 (group 1, n = 18), and 86.5 +/- 18.9 (group 2, n = 68) mm Hg (p < 0.001). Pulmonary vascular resistance indexes (PVRI) were 222 +/- 105 (control), 703 +/- 364 (group 1), and 1,582 +/- 562 (group 2) dyne x s x cm(-5) x m2 (p < 0.001). The mean cardiac indexes were 3.1 (control), 2.8 (group 1), and 2.3 (group 2) L/min/m2 (p < 0.05). Pulmonary capillary wedge pressure (PCw) indicated healthy left heart function. Periinterventional oxygen inhalation improved oxygen saturation in all groups and slightly reduced pulmonary artery pressure and heart rate. Online measurement of pulmonary artery pressure during contrast bolus injection for angiography showed only a minor increase, predominantly in severe pulmonary hypertension (triangle up [difference] PAsyst: 1.3 +/- 1.9 [control], 2.9 +/- 3.4 [group 1], and 3.8 +/- 4.5 [group 2] mm Hg [p < 0.001]). After completion of angiography, right atrial pressure (RAP) and PAsyst were moderately increased: triangle up RAP: 1.4 (control), 2.6 (group 1, p < 0.001), and 3.0 (group 2, p < 0.001) mm Hg; triangle up PAsyst: 3.2 (control), 7.7 (group 1, p < 0.01), and 8.5 (group 2) mm Hg (p < 0.001). PVRI was significantly higher in group 2 (triangle up PVRI: 188 dyne x s x cm(-5) x m2, p < 0.001). Selective pulmonary angiography using iomeprol is safe without critical pressure peaks during selective contrast bolus injection or significant hemodynamic derangement in severe CTPH. Periinterventional oxygen inhalation improved pulmonary circulation.

Outpatient diagnosis of pulmonary embolism: the MIOPED (Manchester Investigation Of Pulmonary Embolism Diagnosis) study

Background and objectives: Pleuritic chest pain, a symptom of pulmonary embolism, is a common presenting symptom in the emergency department. The aim of this study was to validate an algorithm...

Investigating pulmonary embolism in the emergency department with lower limb plethysmography: the Manchester Investigation of Pulmonary Embolism Diagnosis (MIOPED) study

Objectives: To measure the diagnostic accuracy of computerised strain gauge plethysmography in the diagnosis of pulmonary embolism (PE). Methods: Two researchers prospectively recruited 425 patients with pleuritic chest pain presenting...

Respiratory Dead Space Measurement in the Investigation of Pulmonary Embolism in Outpatients With Pleuritic Chest Pain

Pleuritic chest pain is a common presenting condition in the emergency department. A noninvasive bedside rule out test for pulmonary embolism would aid investigating this patient group. Our study aimed to compare the clinical utility of three methods for calculating respiratory dead space in the diagnosis of pulmonary embolism in outpatients with pleuritic chest pain. Prospective diagnostic study. Large city-center emergency department. Between February 2002 and June 2003, 425 patients presenting to the emergency department with pleuritic chest pain were prospectively recruited. Data collection for respiratory dead space was performed in the emergency department by two researchers. The respiratory dead space fraction was calculated independently using three different methods. All patients underwent an independent reference standard diagnostic algorithm to establish the presence or absence of pulmonary embolism. Those with a low modified Wells clinical probability and a normal quantitative d-dimer finding were discharged home. All others followed a reference standard protocol using Prospective Investigation of Pulmonary Embolism Diagnosis-interpreted ventilation/perfusion scanning, CT pulmonary angiography, and digital subtraction pulmonary angiography. All patients were followed up clinically for 3 months. For the Bohr calculation, the area under the receiver operating characteristic curve was 0.62 (95% confidence interval [CI], 0.51 to 0.73), the Enghoff calculation was 0.66 (95% CI, 0.55 to 0.77), and the capillary sample Enghoff was 0.62 (95% CI, 0.49 to 0.65). The optimum Bohr cutoff value gave 100.0% sensitivity (95% CI, 84.5 to 100%) but a low specificity of 22.7% (95% CI, 18.8 to 27.2%). The optimum cutoff points for Enghoff and capillary Enghoff calculations gave sensitivities of 95.3% (95% CI, 77.3 to 99.2%) and 94.4% (95% CI, 74.2 to 99.0%), respectively, with poor specificity. Respiratory dead space analysis does not perform well as a stand-alone diagnostic test for pulmonary embolism in outpatients presenting with pleuritic chest pain.

Diagnosis of Subsegmental Pulmonary Emboli

We measured sensitivity, positive predictive value, and free-response receiver operating characteristic (FROC) of 20 radiologists detecting subsegmental-sized pulmonary emboli in a porcine model using either contrast-enhanced computed tomography (CT) or digital subtraction (DS) pulmonary angiography. Colored methacrylate beads (4.2 and 3.8 mm diameter) were injected into 9 anesthetized juvenile pigs. CT and DS pulmonary angiography images were obtained before and after a pulmonary infiltrate was introduced into the lower lobes. Following imaging, the pigs were euthanized, and the pulmonary arterial tree was cast using clear methacrylate allowing direct visualization of emboli. The 20 radiologists used a custom-made computer application to display the images on their personal computer and record their diagnoses. The results were mailed electronically to the coordinating center for comparison with the cast of the pulmonary vasculature. Twenty-three emboli were included in the statistical analysis. Overall sensitivity for spiral CT and angiography, respectively, was: 60 +/- 18% and 72 +/- 11% (P = 0.06). Positive predictive value for spiral CT and angiography, respectively, was: 49 +/- 24% and 58 +/- 23% (P = 0.25). There was a large variation in both sensitivity and positive predicted values between Readers. There was no difference in sensitivity or positive predictive value between radiologists from community or academic centers (P > 0.27). FROC analysis showed no significant difference between CT or DS (P = 0.27). In conclusion, in this porcine model, there is no overall diagnostic advantage to using DS pulmonary angiography rather than contrast-enhanced spiral CT for the diagnosis of PE when images are interpreted by radiologists located in either academic or community hospital settings.

Overview of prospective investigation of pulmonary embolism diagnosis II

The Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) is a prospective multicenter study funded by the National Heart, Lung, and Blood Institute which began recruiting patients in the fall of 2001. It was designed to assess the efficacy of the spiral computed tomographic pulmonary angiogram in patients suspected of having acute pulmonary embolism (PE). In contrast to the original PIOPED study, which used contrast pulmonary angiography as the primary reference test for PE, PIOPED II will use a composite reference test for venous thromboembolism that is based on the ventilation/perfusion lung scan, venous compression ultrasound of the lower extremities, digital subtraction pulmonary angiography, and contrast venography in various combinations to establish the PE status of the patient. New criteria for ventilation/perfusion lung scan diagnosis have been developed for PIOPED II. This article describes the various techniques that will be used, the combination of the composite reference tests that will be used to determine the PE status of the patient, and the PIOPED II diagnostic criteria that will be used for the ventilation/perfusion scan diagnosis of PE in the study.

An initial study on DSA features of pulmonary hypoperfusion second to cancerous invasion of central pulmonary artery in lung cancer

To study digital subtraction angiography ( DSA) features of pulmonary hypoperfusion in lung cancer with cancerous invasion of central pulmonary artery ( CICPA) . Twenty-six cases of lung cancer combined with CICPA underwent pulmonary DSA. The DSA features of pulmonary hypoperfusion, including pulmonary vessel signs and lung parenchyma signs, were observed, and the time-density curve( TDC) of both abnormal sides and the coordinate normal sides was drawn and analyzed. There were 38 lobar arteries showing cancerous invasion in 26 cases and 34 ( 89. 5%) lobes presenting pulmonary hypoperfusion. There was a good correlation between pulmonary hypoperfusion and the degree of central pulmonary artery ( CPA) stenosis ( P < 0. 05) . DSA pulmonary vessel signs included abrupt cut-off ( 11. 8%, 4/ 34) or less branches ( 88. 2%, 30/ 34) of pulmonary arteries, and disappearance ( 41. 2%, 14/ 34) or decrease ( 58. 8%, 20/ 34) of terminal pulmonary arteries. DSA lung parenchyma signs were pulmonary capillary perfusion disappearing ( 14. 7%, 5/ 34) or weakening ( 85. 3%, 29/ 34) . Pulmonary lobes supplied by central pulmonary arteries invaded by lung cancers usually present pulmonary hypoperfusion. Pulmonary hypoperfusion is closely correlative with the degree of CPA stenosis. Pulmonary vessel signs and lung parenchyma signs are very important phenomena of pulmonary hypoperfusion.

Idiopathic pulmonary artery aneurysm: Digital subtraction pulmonary angiography grossly underestimates the size of the aneurysm

Pulmonary artery aneurysm is a rare disease entity. The majority of cases are associated with congenital cardiovascular diseases, infection, and trauma; idiopathic pulmonary artery aneurysm is extremely rare. Although conventional and digital subtraction pulmonary angiography remains as the imaging modality of choice for the pulmonary vessels, it is invasive and sometimes may be inaccurate. With the advent of spiral computed tomographic angiography (CTA), pulmonary artery aneurysm can be diagnosed noninvasively and accurately. We report a case of a 68-year-old man with idiopathic pulmonary artery aneurysm of the descending branch of right pulmonary artery where the true caliber of the aneurysm was significantly underestimated in the digital subtraction pulmonary angiography. The literatures of this rare condition are reviewed with the emphasis on the application of CTA in this disease.

Sensitivity and Specificity of Radioisotope Right-Left Shunt Measurements and Pulse Oximetry for the Early Detection of Pulmonary Arteriovenous Malformations

To assess the effectiveness of pulse oximetry and radioisotope measurement of right-to-left (R-L) shunt for the early detection of pulmonary arteriovenous malformations (PAVMs) in patients with hereditary hemorrhagic telangiectasia (HHT). Patients with HHT had serial measurements of the following: (1) arterial oxygen saturation (SaO2) by pulse oximetry in erect and supine positions, and on maximal exercise using cycle ergometry; (2) quantitative radioisotope measurements of R-L shunt using IV 99mTc-labeled macroaggregates of albumin; and (3) routine pulmonary function. After percutaneous transcatheter embolization of all PAVMs with feeding vessel diameters > 3 mm, residual PAVMs were assessed with selective digital subtraction pulmonary angiography. Using postembolization angiography as the "gold standard," SaO2 and radioisotope shunt measurements after embolization were analyzed retrospectively using logistic regression to assess the ability of each test to predict for the presence of residual PAVMs. Of the 66 patients included, 40 had small PAVMs remaining postembolization. Using univariate logistic regression, radioisotope shunt and erect saturation showed a significant relationship with the presence of residual PAVMs (p=0.001, 0.005, respectively). Erect SaO2 < or = 96% had 73% sensitivity and 35% specificity for detecting PAVMs. Radioisotope shunt >3.5% of cardiac output had 87% sensitivity and 61% specificity for detecting PAVMs. These results confirm that noninvasive measurements are useful in the screening of patients with HHT for the presence of PAVMs without need for angiography and its associated risks, and that radionuclide scanning is better than pulse oximetry.

False aneurysm of the pulmonary artery induced by a Swan-Ganz catheter: clinical presentation and radiologic management.

This study evaluates retrospectively the clinical presentation, radiographic findings, and angiographic management of false aneurysm of the pulmonary artery resulting from Swan-Ganz catheter placement. Over a 4-year period, seven false aneurysms of the pulmonary artery were diagnosed in five patients (four women, one man) who were 67-81 years old. All five patients underwent Swan-Ganz catheter placement to monitor cardiac surgery--coronary artery bypass grafting in four and mitral valve replacement in one. All patients were anticoagulated. For five patients, we reviewed the medical records and the results of chest radiography, digital subtraction pulmonary angiography, and pulmonary artery embolization. For two patients, we reviewed the results of CT scanning. Non-life-threatening hemoptysis was noted in all cases and occurred in three patients after the Swan-Ganz catheter had been removed (elapsed time of 1-19 days). Chest radiographs revealed a pulmonary infiltrate in one patient and a pulmonary mass in two patients. The results were unremarkable in the other two patients. CT depicted two false aneurysms of the pulmonary artery as round masses with eccentrically enhanced lumina circumscribed by thrombosis. Pulmonary angiography revealed a single false aneurysm in three patients and two false aneurysms in two patients. All false aneurysms were localized in segmental or subsegmental branches of the right middle pulmonary artery (n = 4) or the right lower pulmonary artery (n = 3). All patients were successfully treated with transcatheter steel-coil embolization. Even when the chest radiograph appears unremarkable, patients clinically suspected of developing a false aneurysm of the pulmonary artery after Swan-Ganz catheter placement require enhanced CT or pulmonary angiography to establish the diagnosis. False aneurysms of the pulmonary artery can be treated at the time of pulmonary angiography by steel-coil embolization.