Pulmonary arteries: imaging of pulmonary embolism and beyond

Platelet hyperresponsiveness and increased platelet-neutrophil aggregates in dogs with myxomatous mitral valve disease and pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH.

HYPOTHESIS

Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation.

ANIMALS

Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH.

METHODS

Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA.

RESULTS

Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups.

CONCLUSION AND CLINICAL IMPORTANCE

Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

Optimisation of virtual monoenergetic reconstructions for the diagnosis of pulmonary embolism using photon-counting detector computed tomography angiography

Purpose

Computed tomography (CT) pulmonary angiography is considered the gold standard for pulmonary embolism (PE) diagnosis, relying on the discrimination between contrast and embolus. Photon-counting detector CT (PCD-CT) generates monoenergetic reconstructions through energy-resolved detection. Virtual monoenergetic images (VMI) at low keV can be used to improve pulmonary artery opacification. While studies have assessed VMI for PE diagnosis on dual-energy CT (DECT), there is a lack of literature on optimal settings for PCD-CT-PE reconstructions, warranting further investigation.

Material and methods

Twenty-five sequential patients who underwent PCD-CT pulmonary angiography for suspicion of acute PE were retrospectively included in this study. Quantitative metrics including signal-to-noise ratio (SNR) and contrast-to-noise (CNR) ratio were calculated for 4 VMI values (40, 60, 80, and 100 keV). Qualitative measures of diagnostic quality were obtained for proximal to distal pulmonary artery branches by 2 cardiothoracic radiologists using a 5-point modified Likert scale.

Results

SNR and CNR were highest for the 40 keV VMI (49.3 ± 22.2 and 48.2 ± 22.1, respectively) and were inversely related to monoenergetic keV. Qualitatively, 40 and 60 keV both exhibited excellent diagnostic quality (mean main pulmonary artery: 5.0 ± 0 and 5.0 ± 0; subsegmental pulmonary arteries 4.9 ± 0.1 and 4.9 ± 0.1, respectively) while distal segments at high (80-100) keVs had worse quality.

Conclusions

40 keV was the best individual VMI for the detection of pulmonary embolism by quantitative metrics. Qualitatively, 40-60 keV reconstructions may be used without a significant decrease in subjective quality. VMIs at higher keV lead to reduced opacification of the distal pulmonary arteries, resulting in decreased image quality.

A primary pulmonary artery sarcoma masquerading pulmonary embolism: a case report and literature review

BACKGROUND

Primary pulmonary artery sarcoma (PAS) is an extremely rare malignant tumor with a poor prognosis. The clinical manifestations of PAS are diverse, including dyspnea, chest pain, cough, and hemoptysis. The poor prognosis is often due to delayed diagnosis caused by similarity in imaging findings with pulmonary thromboembolism (PTE). These cues of diagnosis include the "wall eclipsing sign", lobulated bulging margins, gadolinium enhancement during MRI imaging, and FDG uptake during PET/CT imaging. However, there are still many misdiagnoses.

CASE PRESENTATION

This article reports a woman of reproductive age presenting with a pulmonary artery mass. The computed tomographic pulmonary angiography and positron emission tomography/computed tomography did not show obvious signs of pulmonary artery sarcoma, however, contrast-enhanced echocardiography showed moderate perfusion, which helped differentiate between pulmonary artery sarcoma and pulmonary artery thrombosis, leading to timely surgical treatment.

CONCLUSIONS

PAS is a rare form of cancer that can occasionally be visually similar to PTE on radiographic images. Early diagnosis of PAS is of vital importance to the prognosis of the patients. There are several visual cues that can help differentiate between the two conditions. Additionally, contrast-enhanced echocardiography provides additional information on tumor perfusion, offering another effective approach for a prompt and accurate diagnosis.

Echocardiographic Characteristics of Pulmonary Artery Intimal Sarcoma: Comparison With CTPA

OBJECTIVES

This study examined the echocardiographic characteristics of patients with pulmonary artery intimal sarcoma (PAIS) and compared the results with those from computed tomographic pulmonary angiography (CTPA).

METHOD

Twenty-six (26) patients were diagnosed with PAIS at the current institution during the study period, and 23 were eligible for analysis. Echocardiography and CTPA examinations were performed in all enrolled patients.

RESULTS

The echocardiography results showed that most lesions had expansive growth in the left pulmonary artery (PA); the right PA; or a combination of the left PA, right PA, and main PA, with extension to the pulmonary valve and/or right ventricular outflow tract. These lesions also had distinctive sieve-like echogenic signals. Echocardiography also showed that some lesions had lobulated shapes, were nearly round and echolucent or with calcifications, and moved during imaging. The lesion distribution was similar in CTPA and echocardiography (p=0.361), but CTPA was more sensitive in detection of the complete shape (p=0.023).

CONCLUSIONS

The unique echocardiographic characteristics of PAIS, especially the "sieve sign", could help in the diagnosis of this cancer. Transthoracic echocardiography is a non-invasive technique that appears effective in detecting PAIS.

MR Angiography of Pulmonary Vasculature

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.

Giant pulmonary artery aneurysm in a child: Rare complication of congenital heart disease

Key Clinical Message

This case report aims to increase awareness that pulmonary artery aneurysms may occur as a complication of neglected patent ductus arteriosus and should be sought in children with ill-treated congenital heart diseases.

Abstract

Pulmonary artery aneurysm is a rare anomaly with an autopsy prevalence of 1:14,000. These aneurysms can arise secondary to various etiologies, with congenital causes identified in 25% of cases and congenital heart diseases (CHD) responsible for more than half of these cases. A 12-year-old boy with CHD in the form of patent ductus arteriosus (PDA) and irregular clinical follow-up presented with new onset fatigue of 3 months duration. A physical examination revealed anterior chest wall bulging and a continuous murmur. A chest radiograph showed a smooth left hilar region opacity that has a close relation with the left cardiac border. Transthoracic echocardiogram shows no progression from the previous one; there was a large PDA and pulmonary hypertension, but no further information was available. Computed tomography angiography revealed a giant aneurysm of the main pulmonary artery (PA), with a maximum diameter of 8.6 cm, and dilatation of its branches of 3.4 and 2.9 cm for the right and left PA, respectively.

Pulmonary perfusion defect volume on dual-energy CT: prognostic marker of adverse events in patients with suspected pulmonary embolism

To assess whether quantification of pulmonary perfusion defects on dual-energy computed tomography (DECT) relates to adverse events beyond clinical parameters and traditional embolus detection in patients with suspected pulmonary embolism (PE). We included consecutive patients who underwent DECT to rule out acute PE in 2018-2020 and recorded incident adverse events, defined as a composite of short-term (< 30 days) in-hospital all-cause mortality or admission to intensive care unit. Relative perfusion defect volume (PDV) was measured on DECT and indexed by total lung volume. PDV was then related to adverse events using logistic regressions adjusting for clinical parameters, clinical PE pre-test probability (Wells score), and visual PE burden on pulmonary angiography (Qanadli score). Among 136 included patients (63 [46%] females; age: 70 ± 14 years), 19/136 (14%) experienced adverse events during a median hospitalization of 7.5 (4-14) days. Overall, 7/19 (37%) events occurred in those without visible emboli but with measurable perfusion defects. An increase of PDV by one standard deviation was associated with over two times higher odds of adverse events (OR = 2.24; 95%CI:1.37-3.65; p = 0.001). This association remained significant after adjusting for the Wells and Qanadli scores (OR = 2.34; 95%CI:1.20-4.60; p = 0.013). PDV significantly increased the combined discriminatory capacity of Wells and Qanadli scores (AUC 0.76 vs. 0.80; p = 0.011 for difference). DECT-derived PDV may represent a prognostic imaging marker with incremental value beyond clinical and traditional imaging findings, improving risk stratification and aiding clinical management in patients with suspected PE.

Pulmonary arterial wall thickness increased in Behçet's disease patients with major organ involvement: Is it a sign of severity?

OBJECTIVES

Behçet's disease (BD) is a unique systemic vasculitis mainly involving veins, in contrast to other vasculitides. Prior studies have shown that pulmonary arteries (PAs) have a similar structure to systemic veins. In this study we aimed to assess PA wall thickness by transthoracic echocardiography (TTE) in BD patients compared with healthy controls (HCs) and patients with non-inflammatory pulmonary embolism (NIPE).

METHODS

Patients with BD (n = 77) and NIPE (n = 33) and HCs (n = 57) were studied. PA wall thickness was measured from the mid-portion of the main PA with TTE by two cardiologists blinded to cases.

RESULTS

PA wall thickness was significantly lower in HCs [3.6 mm (s.d. 0.3)] compared with NIPE [4.4 mm (s.d. 0.5)] and BD [4.4 mm (s.d. 0.6)] (P < 0.001 for both). PA wall thickness was similar between BD and NIPE (P = 0.6). Among patients with BD, PA wall thickness was significantly higher in patients with major organ involvement compared with mucocutaneous limited disease [4.7 mm (s.d. 0.4) vs 3.7 (0.4), P < 0.001], HCs and NIPE (P < 0.001 and P = 0.006, respectively). PA wall thickness was comparable between patients with vascular and non-vascular major organ involvement [4.6 mm (s.d. 0.5) vs 4.7 (0.3), P = 0.3].

CONCLUSION

We observed that PA wall thickness was significantly higher in BD with major organ involvement compared with patients with only mucocutaneous limited disease, HCs and NIPE. These results suggest that increased PA wall thickness may be a sign of severe disease with major organ involvement in BD.

Improving the imaging diagnostic strategy for pulmonary artery masses based on 18F-FDG PET/CT integrated with CTPA

OBJECTIVE

To evaluate the diagnostic accuracy of computed tomography pulmonary angiography (CTPA) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for pulmonary artery (PA) masses.

METHODS

Of 2889 patients with PA filling defects of PA on CTPA, 79 consecutive patients suspicious for PA malignancy who subsequently underwent ¹⁸F-FDG PET/CT were enrolled. All masses were diagnosed on the basis of pathological findings or clinical imaging follow-up. For each mass, morphological CT signs, standardized uptake value (SUVmax and SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on ¹⁸F-FDG PET/CT were used as diagnostic markers.

RESULTS

Expansive growth, irregular margin, invasion, CT contrast uptake, and wall eclipse sign were strongly associated with the malignant nature of masses. The coexistence of at least 5 CT signs perfectly identified malignant masses, whereas the detection of no more than 4 CT signs did not accurately discriminate between the natures of masses. Mean SUVmax, SUVmean, MTV, and TLG values were significantly higher in malignant masses compared to those in benign masses. The diagnostic accuracy of ¹⁸F-FDG PET/CT parameters (SUV, MTV, and TLG) was excellent in detecting malignant masses. Among patients with 3 or 4 pathological CT signs, SUVmax > 3.4 significantly increased the identification of malignancies.

CONCLUSIONS

CTPA is a useful imaging modality for diagnosing PA masses, especially when at least 5 abnormal CT signs are identified. Similarly, ¹⁸F-FDG PET/CT accurately identified malignant masses and provided additional valuable information on diagnostic uncertainties after CTPA.

Pulmonary Hypertension Caused by Fibrosing Mediastinitis

Pulmonary hypertension (PH) is a progressive and severe disorder in pulmonary hemodynamics. PH can be fatal if not well managed. Fibrosing mediastinitis (FM) is a rare and benign fibroproliferative disease in the mediastinum, which may lead to pulmonary vessel compression and PH. PH caused by FM (PH-FM) is a pathologic condition belonging to group 5 in the World Health Organization PH classification. PH-FM has a poor prognosis because of a lack of effective therapeutic modalities and inappropriate diagnosis. With the development of percutaneous pulmonary vascular interventional therapy, the prognosis of PH-FM has been greatly improved in recent years. This article provides a comprehensive review on the epidemiology, pathophysiologic characteristics, clinical manifestations, diagnostic approaches, and treatment modalities of PH-FM based on data from published reports and our medical center with the goal of facilitating the diagnosis and treatment of this fatal disease.

•

PH-FM, as a type of rare condition in group 5 PH, has a poor prognosis because of a lack of effective therapeutic modalities and frequent misdiagnosis and underdiagnosis.

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The most prevalent trigger of FM is H-FM in the United States and TB-FM in China.

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Imaging findings, including mismatched perfusion defects in the V/Q scan, FM dyad, and FM triad are important diagnostic clues, and clinical classification facilitates decision making in diagnosis and therapeutics.

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Because of the limited efficacy of drug therapy as well as the uncertain effectiveness and high risk of surgical treatment, endovascular interventional modality is currently the preferred therapeutic option, although procedure-related complications and intrastent restenosis after PV intervention need to be addressed.

Lung volume determination by dual-source computed tomography in infants with pulmonary artery sling: a case-control study

BACKGROUND

Pulmonary artery sling (PAS) is associated with tracheal stenosis and left pulmonary artery (LPA) dysplasia in infants, both developmental abnormalities that may lead to pulmonary hypoplasia and lung volume changes. As such, we aimed to monitor the effects of tracheal stenosis and pulmonary vascular malformation on lung volumes in infants with PAS and their correlation with lung volumes in infants with PAS using dual-source computed tomography (DSCT).

METHODS

A case-control study was performed. From May 2009 to June 2017, we retrospectively enrolled patients with surgically confirmed PAS and compared them to matched normal controls (A healthy control group comprising age- and gender-matched patients with adequate imaging data was used for the comparisons.). All the patients underwent DSCT examinations. We measured and compared the diameters of the trachea, main bronchus, and main pulmonary artery (MPA) and its branches, and both lung volumes on the axial, and reconstructed CT images.

RESULTS

There were no statistical differences in the diameters of the MPA or right pulmonary artery (RPA) between patients (N=15) and controls (N=28). The diameter of the main bronchus, the bilateral trachea and the left pulmonary artery were all smaller in the PAS group than in the control group, and significant differences were evident in the left lung volume the right lung volume, and the right-to-left lung volume ratio between the 2 groups. Pearson's correlation and linear regression analyses between the diameters of the trachea and MPA, total lung volume, ipsilateral bronchial and pulmonary artery branches, and ipsilateral lung volume ranged from 0.71 to 0.87 and 0.57 to 0.77 for the control and PAS groups, respectively.

CONCLUSIONS

Tracheal stenosis and LPA dysplasia in infants with PAS cause alterations in lung tissue morphology and physiological development, resulting in reduced bilateral lung volumes.

Pulmonary embolism and computed tomography angiography: Characteristic findings and technical advices

Pulmonary embolism (PE) is a condition due to blood clots obstructing pulmonary arteries, often related to deep venous thrombosis (DVT). PE can be responsible for acute and even life-threatening clinical situations and it may also lead to chronic sequelae such as chronic thromboembolic pulmonary hypertension (CTEPH). Signs and symptoms associated to PE may overlap those of many other diseases (e.g. chest pain, dyspnea, etc.), therefore an accurate clinical evaluation is mandatory before referring the patient to the most appropriate imaging technique. Pulmonary angiography (PA) has been traditionally considered the gold standard regarding the diagnosis of PE and it is also useful regarding the treatment of said condition. However, PA is an invasive technique, implying all the known risks concerning endovascular procedures. Nowadays, computed tomography angiography (CTA) is considered the imaging technique of choice regarding the diagnosis of PE. This technique is readily-available in most centers and it is able to provide high resolution images, although it implies the administration of ionizing radiations and iodinated contrast medium. Conventional CTA has further been improved with the use of ECG-gated protocols, aimed to reduce motion artifacts due to heartbeat and to evaluate other causes of sudden onset chest pain. Moreover, another interesting technique is dual energy computed tomography (DECT), which allows to elaborate iodine maps, allowing to detect areas of hypoperfusion due to the presence of emboli in pulmonary arteries. This review is aimed to describe the main findings related to PE with an emphasis on CTA, also discussing technical aspects concerning image acquisition protocol.

Multimodal Approach of Isolated Pulmonary Vasculitis: A Single-Institution Experience

BACKGROUND

Isolated pulmonary vasculitis (IPV) is a single-organ vasculitis of unknown etiology and may mimic chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to review our clinical experience with pulmonary endarterectomy in patients with CTEPH secondary to IPV.

METHODS

Data were collected prospectively for consecutive patients who underwent pulmonary endarterectomy and had a diagnosis of IPV at or after surgery.

RESULTS

We identified nine patients (six female, median age 48 (23-55) years) with IPV. The diagnosis was confirmed after histopathological examination of all surgical materials. The mean duration of disease before surgery was 88.0 ±70.2 months. Exercise-induced dyspnea was the presenting symptom in all patients. Pulmonary endarterectomy was bilateral in six patients and unilateral in three. No mortality was observed, however, one patient had pulmonary artery stenosis and stent implantation was performed. All patients received immunosuppressive therapies after surgery. Mean pulmonary artery pressure decreased significantly from 30(19-67) mm Hg to 21(15-49) mm Hg after surgery (p <0.05). Pulmonary vascular resistance also improved significantly from 270 (160-1600) to 153 (94-548) dyn/s/cm^-5 (p<0.05). After a median follow-up of 41 months, all but one patient had improved to the New York Heart Association functional class I.

CONCLUSIONS

Isolated pulmonary vasculitis can mimic CTEPH, and these patients can be diagnosed with pulmonary endarterectomy. Furthermore, surgery has not only diagnostic but also therapeutic value for IPV when stenotic and/or thrombotic lesions are surgically accessible. A multidisciplinary experienced CTEPH team is critical for management of these unique patients.

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.