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Ventilation-perfusion scintigraphy in a 78-year-old woman with normal chest radiograph referred for clinical suspicion of chronic thromboembolic pulmonary hypertension (CTEPH). (a) Planar ventilation ( 81m krypton) and perfusion ( 99m Tc macroaggregate albumin) imaging shows multiple segmental and subsegmental defects in normally ventilated lungs, highly suggestive of CTEPH. (b) SPECT perfusion images provide detailed analysis of perfusion defects in coronal plane. ANT = anterior, LAO = left anterior oblique, LPO = left posterior oblique, POST = posterior, RAO = right anterior oblique, RPO = right posterior oblique.
Source publication
Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was fo...
Contexts in source publication
Context 1
... patients with PH and a clear chest radiograph, a normal-near normal V/Q lung scan virtually excludes CTEPH with a sensitivity of 90%-100% and a specificity of 94%-100% (46,47). The presence of mismatched perfusion defects is compatible with CTEPH and requires further work-up in an expert center (6,7,44) (Fig 1). ...
Context 2
... the diagnosis of CTEPH is confirmed, CT angiography can be used for assessment of operability (6) (Figs 9, 10). CT can provide a vascular roadmap for surgical planning and is the best modality for delineation of the proximal extent of the organized thromboembolic material, with good PEA plane correlation (87). ...
Context 3
... subpleural perfusion in the capillary phase of digital subtraction angiography predicts worse outcomes following PEA in operable CTEPH (93). Poor subpleural perfusion is defined as less than or equal to 1.5 cm (approximately one rib width) from the lateral pleura in the capillary phase of digital subtraction angiography on the posterior-anterior views and by lateral views of the dorsal area (Fig 11). In such cases, V/Q lung scanning also shows reduced subpleural perfusion with a preserved ventilation (94). ...
Context 4
... patients with PH and a clear chest radiograph, a normal-near normal V/Q lung scan virtually excludes CTEPH with a sensitivity of 90%-100% and a specificity of 94%-100% (46,47). The presence of mismatched perfusion defects is compatible with CTEPH and requires further work-up in an expert center (6,7,44) (Fig 1). ...
Context 5
... the diagnosis of CTEPH is confirmed, CT angiography can be used for assessment of operability (6) (Figs 9, 10). CT can provide a vascular roadmap for surgical planning and is the best modality for delineation of the proximal extent of the organized thromboembolic material, with good PEA plane correlation (87). ...
Context 6
... subpleural perfusion in the capillary phase of digital subtraction angiography predicts worse outcomes following PEA in operable CTEPH (93). Poor subpleural perfusion is defined as less than or equal to 1.5 cm (approximately one rib width) from the lateral pleura in the capillary phase of digital subtraction angiography on the posterior-anterior views and by lateral views of the dorsal area (Fig 11). In such cases, V/Q lung scanning also shows reduced subpleural perfusion with a preserved ventilation (94). ...
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Citations
... Previous imaging modalities have included chest radiography, echocardiography, right heart catheterization, and pulmonary artery computed tomography angiography (CTA). However, none of them are capable of adequately revealing the thin structure of the pulmonary artery (13). IVUS provides real-time cross-sectional images of blood vessels, presenting a clear view of the thin structure of the blood vessel wall (7,8). ...
... The sensitivity and specificity of PA diameter or PA:Ao for predicting the presence of PH depends on the nature of the individual patient. The Fleischner Society guidelines suggest thresholds of PA diameter and PA:Ao of >30 mm and >0.9 in patients with conditions conferring a high risk (>10%) of PH (including left heart disease, COPD, interstitial lung disease, obstructive sleep apnoea, SSc, chronic kidney disease requiring dialysis, CHD and sickle cell disease), >32 mm and >1.0 in patients with conditions conferring an intermediate risk (1-10%) of PH (including non-SSc CTD, portal hypertension, HIV, previous pulmonary embolism, thalassaemia and schistosomiasis), and >34 mm and >1.1 in those with no known risk factors for PH [31]. Severe aneurysmal PA dilatation may suggest very longstanding PH or chronic left-to-right shunting. ...
... Before assessing for signs of acute or CTEPD, the adequacy of the scan in terms of slice thickness (⩽1 mm), contrast load (⩾250 Hounsfield units in the main PA) and lack of significant breathing and motion artefact should be assessed [31]. Switching to bone windows is preferable to avoid missing signs of CTEPD. ...
Pulmonary hypertension (PH) is defined by the presence of a mean pulmonary arterial pressure >20 mmHg. Current guidelines describe five groups of PH with shared pathophysiological and clinical features. In this paper, the first of a series covering all five PH classification groups, the clinical, radiological and pathological features of pulmonary arterial hypertension (PAH) will be reviewed. PAH may develop in the presence of associated medical conditions or a family history, following exposure to certain medications or drugs, or may be idiopathic in nature. Although all forms of PAH share common histopathological features, the presence of certain pulmonary arterial abnormalities, such as plexiform lesions, and extent of co-existing pulmonary venous involvement differs between the different subgroups. Radiological investigations are key to diagnosing the correct form of PH and a systematic approach to interpretation, especially of computed tomography, is essential.
... This can at least be partly attributed to the difficulties with identifying patients that already present with CTEPH at their PE index event [4,9]. A variety of computed tomography pulmonary angiography (CTPA) parameters, which is the key imaging modality to rule out suspected PE [10], have been suggested to identify CTEPH [11][12][13][14]. These include direct vascular features such as laminated thrombi with obtuse angles to the contrast column, vessel narrowing or complete retraction, intimal irregularities, "webs and bands, " and post-stenotic dilatation. ...
Objectives
To evaluate dual-layer dual-energy computed tomography (dlDECT)–derived pulmonary perfusion maps for differentiation between acute pulmonary embolism (PE) and chronic thromboembolic pulmonary hypertension (CTEPH).
Methods
This retrospective study included 131 patients (57 patients with acute PE, 52 CTEPH, 22 controls), who underwent CT pulmonary angiography on a dlDECT. Normal and malperfused areas of lung parenchyma were semiautomatically contoured using iodine density overlay (IDO) maps. First-order histogram features of normal and malperfused lung tissue were extracted. Iodine density (ID) was normalized to the mean pulmonary artery (MPA) and the left atrium (LA). Furthermore, morphological imaging features for both acute and chronic PE, as well as the combination of histogram and morphological imaging features, were evaluated.
Results
In acute PE, normal perfused lung areas showed a higher mean and peak iodine uptake normalized to the MPA than in CTEPH (both p < 0.001). After normalizing mean ID in perfusion defects to the LA, patients with acute PE had a reduced average perfusion (ID mean,LA ) compared to both CTEPH patients and controls ( p < 0.001 for both). ID mean,LA allowed for a differentiation between acute PE and CTEPH with moderate accuracy (AUC: 0.72, sensitivity 74%, specificity 64%), resulting in a PPV and NPV for CTEPH of 64% and 70%. Combining ID mean,LA in the malperfused areas with the diameter of the MPA (MPA dia ) significantly increased its ability to differentiate between acute PE and CTEPH (sole MPA dia : AUC: 0.76, 95%-CI: 0.68–0.85 vs. MPA dia + 256.3 * ID mean,LA − 40.0: AUC: 0.82, 95%-CI: 0.74–0.90, p = 0.04).
Conclusion
dlDECT enables quantification and characterization of pulmonary perfusion patterns in acute PE and CTEPH. Although these lack precision when used as a standalone criterion, when combined with morphological CT parameters, they hold potential to enhance differentiation between the two diseases.
Clinical relevance statement
Differentiating between acute PE and CTEPH based on morphological CT parameters is challenging, often leading to a delay in CTEPH diagnosis. By revealing distinct pulmonary perfusion patterns in both entities, dlDECT may facilitate timely diagnosis of CTEPH, ultimately improving clinical management.
Key Points
• Morphological imaging parameters derived from CT pulmonary angiography to distinguish between acute pulmonary embolism and chronic thromboembolic pulmonary hypertension lack diagnostic accuracy.
• Dual-layer dual-energy CT reveals different pulmonary perfusion patterns between acute pulmonary embolism and chronic thromboembolic pulmonary hypertension.
• The identified parameters yield potential to enable more timely identification of patients with chronic thromboembolic pulmonary hypertension.
... right heart chambers. More frequently, it helps in the clinical classification of PH by showing signs of chronic respiratory disease (CTD-ILD), PVOD-like (lymphadenopathy, centrilobular groundglass opacities, septal lines) and/or CTEPH (filling defects, webs or bands inside Pas, PA retraction/dilatation, mosaic perfusion, and enlarged bronchial arteries) [79]. ...
... Cardiac MRI can show features suggestive of PH, such as dilatation of PA or right heart chambers. More importantly, it allows measurements of several prognostic determinants, such as RV ejection fraction, SVI and RV end-systolic volume index (RVESVI) [79]. ...
... V/Q lung scan is the gold standard exam to exclude CTEPH and should be part of the initial assessment of CTD-PH patients. In case of CTEPH, it typically shows mismatched perfusion defects persisting after at least 3 months of anticoagulation, with a higher sensitivity but lower specificity than chest angio-CT [79]. ...
... According to Min et al. [7,16] MPAd and the diameter of the ascending aorta (AAd) were measured at the same level, meanwhile, the Cobb angle was the angle between the interventricular septum and the line connecting the midpoint of the sternum and the thoracic vertebral spinous process on the transversal image. Figure 2 shows the right and left ventricular longitudinal diameters and transversal diameters (RVld, RVtd, LVld, LVtd) and the right atrium (RAld, RAtd), the maximum four-chamber area (RVa, LVa, RAa, LAa) were measured on the fourchamber cardiac view [8,9]. ...
... In this study, we re-evaluated cardiovascular metrics on CTPA in the prediction of PH using the updated diagnostic criteria of the 2022 ESC/ERS Guidelines [15]. And there are several major findings: (I) both MPAd and RVFWT were identified as independent Although RHC has been the gold standard for the diagnosis of PH, non-invasive imaging metrics obtained from various modalities, such as echocardiography, CT, and MRI, have been widely utilized in clinical practice for evaluating PH [16]. Previous studies have demonstrated that some metrics such as MPAd, MPAd/AAd ratio, and septal angle can help detect PH. ...
... Similarly, Swift et al. [6] proposed that a pulmonary artery diameter of 30 mm represents a compromise Moreover, according to the old criteria, we found that the cut-off value for MPAd in PH patients was 30.4 mm, with a high sensitivity of 91.8% and moderate specificity of 77.1%. The above results could potentially explain the inconsistent results obtained from using static pulmonary artery (PA) dimensions on routine chest CT scans for the diagnosis of PH [16]. ...
Purpose
To re-assess cardiovascular metrics on computed tomography pulmonary angiography (CTPA) in predicting pulmonary hypertension (PH) under the 2022 ESC/ERS guidelines.
Materials and methods
This observational study retrospectively included 272 patients (female 143, mean age = 54.9 ± 12.5 years old) with suspected PH. 218 patients were grouped to evaluate cardiovascular metrics on CTPA and develop a binary logistic regression model. The other 54 patients were grouped into the validation group to assess the performance of the prediction model under the updated criteria. Based on mean pulmonary artery pressure (mPAP), patients were divided into three groups: group A consisted of patients with mPAP ≤ 20 mmHg, group B included patients with 20 mmHg < mPAP < 25 mmHg, and group C comprised patients with mPAP ≥ 25 mmHg. Cardiovascular metrics among the three groups were compared, and receiver operating characteristic curves (ROCs) were used to evaluate the performance of cardiovascular metrics in predicting mPAP > 20 mmHg.
Results
The main pulmonary arterial diameter (MPAd), MPAd/ascending aorta diameter ratio (MPAd/AAd ratio), and right ventricular free wall thickness (RVFWT) showed significant differences among the three groups ( p < 0.05). The area under curve (AUC) of MPAd was larger than MPAd/AAd ratio and RVFWT. A MPAd cutoff value of 30.0 mm has a sensitivity of 83.1% and a specificity of 90.4%. The AUC of the binary logistic regression model ( Z = − 12.98187 + 0.31053 MPAd + 1.04863 RVFWT) was 0.938 ± 0.018. In the validation group, the AUC, sensitivity, specificity, and accuracy of the prediction model were 0.878, 92.7%, 76.9%, and 88.9%, respectively.
Conclusion
Under the updated criteria, MPAd with a threshold value of 30.0 mm has better sensitivity and specificity in predicting PH. The binary logistic regression model may improve the diagnostic accuracy.
Critical relevance statement
Under the updated criteria, the main pulmonary arterial diameter with a threshold value of 30.0 mm has better sensitivity and specificity in predicting pulmonary hypertension. The binary logistic regression model may improve diagnostic accuracy.
Key points
• According to 2022 ESC/ERS guidelines, a MPAd cutoff value of 30.0 mm has better sensitivity and specificity in predicting mPAP > 20 mmHg
• A binary logistic regression model (Z = − 12.98187 + 0.31053 MPAd + 1.04863 RVFWT) was developed and had a sensitivity, specificity, and accuracy of 92.7%, 76.9%, and 88.9% in predicting mPAP > 20 mmHg.
• A binary logistic regression prediction model outperforms MPAd in predicting mPAP > 20 mmHg.
Graphical Abstract
... Pulmonary hypertension is a silent disease, frequently only discovered at a late stage. 54,55 The central problem with this disorder is that the right heart is not designed to generate high pressures. It is designed for accommodating the changes in volume associated with exercise (acute changes in volume) and pregnancy (slow changes in volume). ...
... 57,58 Chronic Thromboembolic Pulmonary Hypertension CTEPH is an insidious and slowly progressive disease. 55 One hypothesis regarding the etiology of CTEPH is that this requires years of subclinical thromboembolic disease during which multiple small emboli obstruct the peripheral pulmonary capillary bed. This raises the mean pulmonary artery pressure slowly and patients begin to limit their activity incrementally until they become short of breath at rest. ...
... Main pulmonary artery diameter greater than 3.15 cm only suggests the possibility of pulmonary hypertension ( Table 5). 55,64,65 On chest CT examinations, Mahammedi and colleagues 64 studied 298 patients with known pulmonary hypertension from right heart catheterization and 102 controls. They found that the mean pulmonary artery diameter and mean pulmonary artery diameter/ ascending aorta diameter ratio had the highest correlation with pulmonary artery pressure (r 5 0.51 and 0.53, respectively; P < .001). ...
Pulmonary MR angiography (MRA) is a useful alternative to computed tomographic angiography (CTA) for the study of the pulmonary vasculature. For pulmonary hypertension and partial anomalous pulmonary venous return, a cardiac MR imaging and the pulmonary MRA are useful for flow quantification and planning treatment. For the diagnosis of pulmonary embolism (PE), MRA-PE has been shown to have non-inferior outcomes at 6 months when compared with CTA-PE. Over the last 15 years, pulmonary MRA has become a routine and reliable examination for the workup of pulmonary hypertension and the primary diagnosis of PE at the University of Wisconsin.
... 63,64 Advancements in CT techniques have led to improved visualisation of the detailed morphology of chronic thromboembolic lesions in segmental and subsegmental pulmonary arteries. [65][66][67] Mural thrombus, complete arterial occlusions, intravascular webs or bands, and artery narrowing or retraction are all signs of CTEPD and can accurately be visualised on CTPA (figure 2). Very peripheral chronic thromboembolic disease is difficult to recognise on CTPA because of the small calibre of the vessels, but its proper visualisation is very important, not only for the diagnosis, but also for optimal treatment planning. ...
Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism. Important advances have enabled better understanding, characterisation, and treatment of this condition. Guidelines recommending systematic follow-up after acute pulmonary embolism, and the insight that CTEPH can mimic acute pulmonary embolism on initial presentation, have led to the definition of CTEPH imaging characteristics, the introduction of artificial intelligence diagnosis pathways, and thus the prospect of easier and earlier CTEPH diagnosis. In this Series paper, we show how the understanding of CTEPH as a sequela of inflammatory thrombosis has driven successful multidisciplinary management that integrates surgical, interventional, and medical treatments. We provide imaging examples of classical major vessel targets, describe microvascular targets, define available tools, and depict an algorithm facilitating the initial treatment strategy in people with newly diagnosed CTEPH based on a multidisciplinary team discussion at a CTEPH centre. Further work is needed to optimise the use and combination of multimodal therapeutic options in CTEPH to improve long-term outcomes for patients.
... Previous reports indicate that LAMTOR1 collaborates to regulate neovascularization in the pulmonary endothelium [81]. In PAH, within the pulmonary wall thickness, a concomitant increase occurs in neovascularization of the vasa vasorum [82,83]. The effect promoted by EVs but not by cells might indicate that some of the information produced by cells is being extensively packaged in the EVs. ...
Aims:
To evaluate BM-MSCs and their extracellular vesicles (EVs) preconditioned with hypoxia or normoxia in experimental pulmonary arterial hypertension (PAH).
Main methods:
BM-MSCs were isolated and cultured under normoxia (MSC-N, 21%O2) or hypoxia (MSC-H, 1%O2) for 48 h. EVs were then isolated from MSCs under normoxia (EV-N) or hypoxia (EV-H). PAH was induced in male Wistar rats (n = 35) with monocrotaline (60 mg/kg); control animals (CTRL, n = 7) were treated with saline. On day 14, PAH animals received MSCs or EVs under normoxia or hypoxia, intravenously (n = 7/group). On day 28, right ventricular systolic pressure (RVSP), pulmonary acceleration time (PAT)/pulmonary ejection time (PET), and right ventricular hypertrophy (RVH) index were evaluated. Perivascular collagen content, vascular wall thickness, and endothelium-mesenchymal transition were analyzed.
Key findings:
PAT/PET was lower in the PAH group (0.26 ± 0.02, P < 0.001) than in CTRLs (0.43 ± 0.02) and only increased in the EV-H group (0.33 ± 0.03, P = 0.014). MSC-N (32 ± 6 mmHg, P = 0.036), MSC-H (31 ± 3 mmHg, P = 0.019), EV-N (27 ± 4 mmHg, P < 0.001), and EV-H (26 ± 5 mmHg, P < 0.001) reduced RVSP compared with the PAH group (39 ± 4 mmHg). RVH was higher in the PAH group than in CTRL and reduced after all therapies. All therapies decreased perivascular collagen fiber content, vascular wall thickness, and the expression of endothelial markers remained unaltered; only MSC-H and EV-H decreased expression of mesenchymal markers in pulmonary arterioles.
Significance:
MSCs and EVs, under normoxia or hypoxia, reduced right ventricular hypertrophy, perivascular collagen, and vessel wall thickness. Under hypoxia, MSCs and EVs were more effective at improving endothelial to mesenchymal transition in experimental PAH.
... Enlargement of the pulmonary artery diameter (PAd) or increased ratio of the PAd to aorta diameter (PA:AA) has been associated with increased mortality in patients with chronic obstructive pulmonary disease (COPD), 1,2 interstitial lung disease, [3][4][5] pulmonary arterial hypertension (PAH), 6,7 chronic thromboembolic pulmonary hypertension (CTEPH), 7,8 chronic systolic heart failure, 9 and severe COVID-19 infection. 10 This is not surprising, as pulmonary artery enlargement on CTPA has been shown to correlate with other better defined assessments of pulmonary hypertension, including echocardiography and right heart catheterization, [11][12][13][14][15][16][17][18][19] and the presence of pulmonary hypertension is associated with a poor prognosis in many of these conditions. [20][21][22][23] However, pulmonary artery enlargement has not been associated with increased mortality in the general population. 2 Patients who undergo CTPA in the Emergency Department (ED) are often evaluated for cardiorespiratory symptoms. ...
Findings of an enlarged pulmonary artery diameter (PAd) and increased pulmonary artery to ascending aorta ratio (PA:AA) on contrast-enhanced computed tomography pulmonary angiography (CTPA) are associated with increased mortality in particular groups of patients with cardiopulmonary disease. However, the frequency and prognostic significance of these incidental findings has not been studied in unselected patients evaluated in the Emergency Department (ED). This study aims to determine the prevalence and associated prognosis of enlarged pulmonary artery measurements in an ED cohort. We measured PA and AA diameters on 990 CTPA studies performed in the ED. An enlarged PA diameter was defined as >27 mm in females and >29 mm in males, while an increased PA:AA was defined as >0.9. Poisson regression was performed to calculate prevalence ratios for relevant comorbidities, and multivariable Cox regression was performed to calculate hazard ratios (HR) for mortality of patients with enlarged pulmonary artery measurements. An enlarged PAd was observed in 27.9% of 990 patients and was more commonly observed in older patients and in patients with obesity or heart failure. Conversely, PA:AA was increased in 34.2% of subjects, and was more common in younger patients and those with peripheral vascular disease or obesity. After controlling for age, sex, and comorbidities, both enlarged PAd (HR 1.29, 95% CI 1.00-1.68, p = 0.05) and PA:AA (HR 1.70, 95% CI 1.31-2.22 p < 0.01) were independently associated with mortality. In sum, enlarged PAd and increased PA:AA are common in patients undergoing CTPAs in the ED setting and both are independently associated with mortality.
... Per current guidelines, non-invasive imaging modalities, V /Q lung scintigraphy or singlephoton emission CT (SPECT), are the recommended investigations in patients with PH to look for CTEPH [9,10]. However, assessment of severity still requires an invasive procedure such as right heart catheterization (RHC) through the assessment of the cardiac index in particular [5,9,11]. ...
... This PBV was shown to be correlated with qualitative and quantitative data provided by different lung perfusion nuclear methods using 99mTc macro aggregated albumin (MAA-Tc99m) such as multiplanar scintigraphy or cadmium-zinc-telluride camera SPECT-CT [15,16]. In CTEPH patients, the PBV was reported to be a marker of perfusion failure and correlated to hemodynamic parameters [11,[17][18][19][20]. However, studies evaluating the PBV have been restricted so far, with flawed qualitative or semi-quantitative methods that are dependent on an observer's experience, do not account for the absolute iodine concentration in the lungs, and do not allow it to be normalized to the concentration in the pulmonary trunk. ...
... This may have strongly impacted the PBV values because of a collateral circulation that may participate by 30% of the pulmonary inflow [28,29]. An injection at an earlier time would have been preferable to highlight a pulmonary vascular obstruction and limit the participation of systemic vascularization, such as suggested in other studies [11,30,31]. Lastly, a fifth study in 2022 by Kroeger et al. used an automated semi-quantitative volumetric process to estimate the PBV and found a correlation between the score of malperfused volume and the PVR but no correlation with the mPAP, results comparable to those of the present study [32]. ...
In chronic thromboembolic pulmonary hypertension (CTEPH), assessment of severity requires right heart catheterization (RHC) through cardiac index (CI). Previous studies have shown that dual-energy CT allows a quantitative assessment of the lung perfusion blood volume (PBV). Therefore, the objective was to evaluate the quantitative PBV as a marker of severity in CTEPH. In the present study, thirty-three patients with CTEPH (22 women, 68.2 ± 14.8 years) were included from May 2017 to September 2021. Mean quantitative PBV was 7.6% ± 3.1 and correlated with CI (r = 0.519, p = 0.002). Mean qualitative PBV was 41.1 ± 13.4 and did not correlate with CI. Quantitative PBV AUC values were 0.795 (95% CI: 0.637–0.953, p = 0.013) for a CI ≥ 2 L/min/m2 and 0.752 (95% CI: 0.575–0.929, p = 0.020) for a CI ≥ 2.5 L/min/m2. In conclusion, quantitative lung PBV outperformed qualitative PBV for its correlation with the cardiac index and may be used as a non-invasive marker of severity in CTPEH patients.
