Pulmonary infarction: spectrum of findings on multidetector helical CT

Debunking a mythology: Atelectasis is not a cause of postoperative fever

Most physicians appreciate that practicing medicine is a commitment to continuous learning. However, "learning" can be mistakenly understood as simply the acquisition of facts and new knowledge. But learning also necessitates the constant re-examination and challenging of one's existing body of knowledge, as misinformation persists when one's beliefs are not challenged or questioned in the light of new information. One example is the pervasive belief that postoperative atelectasis causes fever despite ample evidence to the contrary. Herein we examine the imaging characteristics of atelectasis, and the means of differentiation of atelectasis from consolidation. We also explore the history of this persistent myth and review the existing literature on the actual causes of postoperative fever.

Computed tomography diagnosis of pulmonary infarction in acute pulmonary embolism

INTRODUCTION

Pulmonary infarction is a common sequela of pulmonary embolism (PE) but lacks a diagnostic reference standard. CTPA in the setting of acute PE does not reliably differentiate infarction from other consolidations, such as reversible alveolar hemorrhage or atelectasis. We aimed to assess the diagnostic accuracy for recognizing pulmonary infarction on CT in the acute phase of PE, with follow-up CT as reference.

MATERIALS AND METHODS

Initial and follow-up CT scans of 33 patients with acute PE were retrospectively assessed. Two radiologists independently evaluated the presence and size of suspected pulmonary infarction on the initial CT. Confirmation of infarction was established by detection of residual densities on follow-up CT. Sensitivity, specificity and interobserver variability were calculated.

RESULTS

In total, 60 presumed infarctions were found in 32 patients, of which 34 infarctions in 21 patients could be confirmed at follow-up. On patient-level, observers' sensitivity/specificity were 91 %/9 %, and 73 %/46 %, respectively, with interobserver agreement by Kappa's coefficient of 0.17. Confirmed infarctions were usually larger than false positive lesions (median approximate volume of 6.6 mL [IQR 0.84-21.3] vs. 1.3 mL [IQR 0.57-6.5], p = 0.040), but still small. An occluding thrombus in a supplying vessel was predictive for confirmed infarction (OR 11, 95%CI 2.1-55), but was not discriminative.

CONCLUSIONS

Pulmonary infarction is a common finding in acute PE, and generally small. Radiological identification of infarction was challenging, with considerable interobserver variability. Complete obstruction of the supplying (sub)segmental pulmonary artery was found as the strongest predictor for pulmonary infarction but was not demonstrated to be discriminative.

A Case of Lung Cavity Incidentally Discovered Following Evaluation for Pulmonary Embolism

Cavitary lung lesions manifest following a wide variety of pathological processes, which are typically delineated as infectious and non-infectious. With respect to noninfectious causes, malignancies are among the most worrisome, while autoimmune and embolic processes are less frequent and less severe in prognosis. While it is important to differentiate between these etiologies, treatment may resort to surgical procedures for both diagnostic and curative intent. This case involves the incidental finding of a cavitary lung lesion following pulmonary embolism evaluation. Following confirmation of deep venous thrombosis and pulmonary embolism, the patient was admitted to the hospital, administered anticoagulants, and monitored for changes in respiratory status. Outpatient follow-up showed vast improvement in the cavity without antibiotic/chemotherapeutic treatment. Embolic events were attributed to Factor V Leiden diagnosis. This manuscript aims to discuss etiologies of lung cavities and how treatment strategies may differ depending on pathological processes and concomitant patient comorbidities. Special attention will be paid to pulmonary cavity evaluation in the acute hospital setting.

Clinical predictors and outcomes of pulmonary infarction in patients with central pulmonary embolism

BACKGROUND

Given the heterogeneity of predisposing factors associated with pulmonary infarction (PI) and the lack of clinically relevant outcomes among patients with acute pulmonary embolism (PE) complicated by PI, further investigation is required.

METHODS

Retrospective study of patients with central PE in an 11-year period. Data were stratified according to the diagnosis of PI. Multivariable logistic regression analysis was used to analyze factors associated with PI development and determine if PI was associated with severe hypoxemic respiratory failure and mechanical ventilation use.

RESULTS

Of 645 patients with central PE, 24% (n = 156) had PI. After adjusting for demographics, comorbidities, and clinical features on admission, only age (OR 0.98, CI 0.96-0.99; p = 0.008) was independently associated with PI. Regarding outcomes, 35% (n = 55) had severe hypoxemic respiratory failure, and 19% (n = 29) required mechanical ventilation. After adjusting for demographics, PE severity, and right ventricular dysfunction, PI was independently associated with severe hypoxemic respiratory failure (OR 1.78; CI 1.18-2.69, p = 0.005) and mechanical ventilation (OR 1.92; CI 1.14-3.22, p = 0.013).

CONCLUSIONS

Aging is a protective factor against PI. In acute central PE, subjects with PI had higher odds of developing severe hypoxemic respiratory failure and requiring mechanical ventilation.

Chronic thromboembolic pulmonary hypertension is associated with a loss of total lung volume on computed tomography

BACKGROUND

Although lung volumes are usually normal in individuals with chronic thromboembolic pulmonary hypertension (CTEPH), approximately 20%-29% of patients exhibit a restrictive pattern on pulmonary function testing.

AIM

To quantify longitudinal changes in lung volume and cardiac cross-sectional area (CSA) in patients with CTEPH.

METHODS

In a retrospective cohort study of patients seen in our hospital between January 2012 and December 2019, we evaluated 15 patients with CTEPH who had chest computed tomography (CT) performed at baseline and after at least 6 mo of therapy. We matched the CTEPH cohort with 45 control patients by age, sex, and observation period. CT-based lung volumes and maximum cardiac CSAs were measured and compared using the Wilcoxon signed-rank test and the Mann-Whitney u test.

RESULTS

Total, right lung, and right lower lobe volumes were significantly reduced in the CTEPH cohort at follow-up vs baseline (total, P = 0.004; right lung, P = 0.003; right lower lobe; P = 0.01). In the CTEPH group, the reduction in lung volume and cardiac CSA was significantly greater than the corresponding changes in the control group (total, P = 0.01; right lung, P = 0.007; right lower lobe, P = 0.01; CSA, P = 0.0002). There was a negative correlation between lung volume change and cardiac CSA change in the control group but not in the CTEPH cohort.

CONCLUSION

After at least 6 mo of treatment, CT showed an unexpected loss of total lung volume in patients with CTEPH that may reflect continued parenchymal remodeling.

Impact of pulmonary infarction in pulmonary embolism on presentation and outcomes

BACKGROUND

Pulmonary infarction (PI) is relatively common in pulmonary embolism (PE). The association between PI and persistent symptoms or adverse events is largely unknown.

AIM

To evaluate the predictive value of radiological PI signs at acute PE diagnosis on 3-month outcomes.

METHODS

We studied a convenience cohort with computed tomography pulmonary angiography (CTPA)-confirmed PE for whom extensive 3-month follow-up data were available. The CTPAs were re-evaluated for signs of suspected PI. Associations with presenting symptoms, adverse events (recurrent thrombosis, PE-related readmission and mortality) and self-reported persistent symptoms (dyspnea, pain and post-PE functional impairment) at 3-month follow-up were investigated using univariate Cox regression analysis.

RESULTS

At re-evaluation of the CTPAs, 57 of 99 patients (58 %) had suspected PI, comprising a median of 1 % (IQR 1-3) of total lung parenchyma. Patients with suspected PI more often presented with hemoptysis (11 % vs. 0 %) and pleural pain (OR 2.7, 95%CI 1.2-6.2), and with more proximal PE on CTPA (OR 1.6, 95%CI 1.1-2.4) than patients without suspected PI. There was no association with adverse events, persistent dyspnea or pain at 3-month follow-up, but signs of PI predicted more functional impairment (OR 3.03, 95%CI 1.01-9.13). Sensitivity analysis with the largest infarctions (upper tertile of infarction volume) yielded similar results.

CONCLUSIONS

PE patients radiologically suspected of PI had a different clinical presentation than patients without those signs and reported more functional limitations after 3 months of follow-up, a finding that could guide patient counselling.

Clinical Course of Suspected Diagnosis of Pulmonary Tumor Thrombotic Microangiopathy: A 10-Year Experience of Rapid Progressive Right Ventricular Failure Syndrome in Advanced Cancer Patients

BACKGROUND AND OBJECTIVES

Several cases involving severe right ventricular (RV) failure in advanced cancer patients have been found to be pulmonary tumor thrombotic microangiopathies (PTTMs). This study aimed to discover the nature of rapid RV failure syndrome with a suspected diagnosis of PTTM for better diagnosis, treatment, and prognosis prediction in clinical practice.

METHODS

From 2011 to 2021, all patients with clinically suspected PTTM were derived from the one tertiary cancer hospital with more than 2000 in-hospital bed.

RESULTS

A total of 28 cases of clinically suspected PTTM with one biopsy confirmed case were included. The most common cancer types were breast (9/28, 32%) and the most common tissue type was adenocarcinoma (22/26, 85%). The time interval from dyspnea New York Heart Association (NYHA) Grade 2, 3, 4 to death, thrombocytopenia to death, desaturation to death, admission to death, RV failure to death, cardiogenic shock to death were 33.5 days, 14.5 days, 7.4 days, 6.4 days, 6.1 days, 6.0 days, 3.8 days and 1.2 days, respectively. The NYHA Grade 4 to death time was 7 days longer in those who received chemotherapy (7.1 days vs. 13.8 days, p value=0.030). However, anticoagulation, vasopressors or intensive care could not change clinical course.

CONCLUSIONS

Rapid RV failure syndrome with a suspected diagnosis of PTTM showed a rapid progressive course from symptom onset to death. Although chemotherapy was effective, increased life survival was negligible, and treatments other than chemotherapy did not help to improve the patient's prognosis.

A Frequently Missed Pulmonary Infarction: Clinical and 18F-FDG PET/CT Manifestation of Hilar Tumor-Induced Pulmonary Infarction

PURPOSE

This study aimed to summarize the clinical and 18F-FDG PET/CT manifestations of hilar tumor-induced pulmonary infarction.

METHODS

A retrospective analysis was performed on patients with hilar masses who underwent FDG PET/CT scans between July 2015 and January 2021 and had complete clinical data. Pulmonary infarction was confirmed by concurrent chest CT and imaging follow-up or pathology.

RESULTS

A total of 58 patients (mean age, 56 [SD, 13] years; 44 males) with 122 infarcts were included in the study. Hilar masses were mostly associated with small cell lung cancer (64%). The most common clinical manifestations were cough (64%) and hemoptysis (36%). Most patients (62%) had multiple pulmonary infarcts. The CT findings of pulmonary infarcts included the "Hampton hump" (48%) and patchy consolidation (52%). The density of infarcts included "bubbly consolidation" (61%) and "homogenous consolidation" (39%). The metabolic activity of 95 infarcts (78%) was higher than lung parenchyma, with the SUVmax of 3.3 (SD, 1.1). The metabolic patterns on PET/CT were "rim sign," "mismatch between PET and CT," and "no metabolism." Pulmonary vein involvement was found in 25 patients (43%), pleural effusion in 22 patients (38%), and the pleural curvilinear sign in 8 patients (14%).

CONCLUSIONS

The clinical manifestations of hilar tumor-induced pulmonary infarction are not specific, and 18F-FDG PET/CT could be an effective diagnostic tool.

[Management of Adult Community-Acquired Pneumonia and Prevention - Update 2021 - Guideline of the German Respiratory Society (DGP), the Paul-Ehrlich-Society for Chemotherapy (PEG), the German Society for Infectious Diseases (DGI), the German Society of Medical Intensive Care and Emergency Medicine (DGIIN), the German Viological Society (DGV), the Competence Network CAPNETZ, the German College of General Practitioneers and Family Physicians (DEGAM), the German Society for Geriatric Medicine (DGG), the German Palliative Society (DGP), the Austrian Society of Pneumology Society (ÖGP), the Austrian Society for Infectious and Tropical Diseases (ÖGIT), the Swiss Respiratory Society (SGP) and the Swiss Society for Infectious Diseases Society (SSI)]

The present guideline provides a new and updated concept of the management of adult patients with community-acquired pneumonia. It replaces the previous guideline dating from 2016.The guideline was worked out and agreed on following the standards of methodology of a S3-guideline. This includes a systematic literature search and grading, a structured discussion of recommendations supported by the literature as well as the declaration and assessment of potential conflicts of interests.The guideline has a focus on specific clinical circumstances, an update on severity assessment, and includes recommendations for an individualized selection of antimicrobial treatment.The recommendations aim at the same time at a structured assessment of risk for adverse outcome as well as an early determination of treatment goals in order to reduce mortality in patients with curative treatment goal and to provide palliation for patients with treatment restrictions.

Clinical utility of the updated European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and the Mycoses Study Group Education and Research Consortium computed tomography criteria of invasive pulmonary aspergillosis in hematological malignancies

Invasive pulmonary aspergillosis is a life-threatening complication in the cases of patients with hematologic malignancies. In December 2019, the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and the Mycoses Study Group Education and Research Consortium published a revision and an update of the consensus definitions of invasive fungal disease. The aim of this study was to evaluate the signs and radiologic patterns of early-stage invasive pulmonary aspergillosis in computed tomography in patients with hematologic entities according to the latest criteria.

This retrospective analysis of a baseline high-resolution computed tomography included neutropenic patients with hematological malignancies and probable invasive pulmonary aspergillosis. The data were collected between the years 2017 and 2019. Computed tomography was performed within 72 h from the beginning of clinical symptoms: fever, dyspnea or nonproductive cough. CT scans were analyzed by two independent radiologists according to the standardized protocol based on predefined criteria.

All 35 evaluated patients had typical lesions for early-stage invasive aspergillosis. Wedge-shaped infiltrates were noted in 48.6% of patients. In this group, 40% of patients had coexisting atypical radiological findings. In 11.4% of patients, wedge-shape consolidations were noted as the only type of lesions.

Employment of the latest EORTC/MSG criteria increased diagnostic value of the baseline high resolution computed tomography in our study group by 11.4%.

CT for Evaluation of Hemoptysis

Hemoptysis, which is defined as expectoration of blood from the alveoli or airways of the lower respiratory tract, is an alarming clinical symptom with an extensive differential diagnosis. CT has emerged as an important noninvasive tool in the evaluation of patients with hemoptysis, and the authors present a systematic but flexible approach to CT interpretation. The first step in this approach involves identifying findings of parenchymal and airway hemorrhage. The second step is aimed at determining the mechanism of hemoptysis and whether a specific vascular supply can be implicated. Hemoptysis can have primary vascular and secondary vascular causes. Primary vascular mechanisms include chronic systemic vascular hypertrophy, focally damaged vessels, a dysplastic lung parenchyma with systemic arterial supply, arteriovenous malformations and fistulas, and bleeding at the capillary level. Evaluating vascular mechanisms of hemoptysis at CT also entails determining if a specific vascular source can be implicated. Although the bronchial arteries are responsible for most cases of hemoptysis, nonbronchial systemic arteries and the pulmonary arteries are important potential sources of hemoptysis that must be recognized. Secondary vascular mechanisms of hemoptysis include processes that directly destroy the lung parenchyma and processes that directly invade the airway. Understanding and employing this approach allow the diagnostic radiologist to interpret CT examinations accurately in patients with hemoptysis and provide information that is best suited to directing subsequent treatment. ^©RSNA, 2021.

Pulmonary infarction in acute pulmonary embolism

Pulmonary infarction results from occlusion of the distal pulmonary arteries leading to ischemia, hemorrhage and ultimately necrosis of the lung parenchyma. It is most commonly caused by acute pulmonary embolism (PE), with a reported incidence of around 30%. Following an occlusion of the pulmonary artery, the bronchial arteries are recruited as primary source of perfusion of the pulmonary capillaries. The relatively higher blood pressure in the bronchial circulation causes an increase in the capillary blood flow, leading to extravasation of erythrocytes (i.e. alveolar hemorrhage). If this hemorrhage cannot be resorbed, it results in tissue necrosis and infarction. Different definitions of pulmonary infarction are used in literature (clinical, radiological and histological), although the diagnosis is nowadays mostly based on radiological characteristics. Notably, the infarcted area is only replaced by a fibrotic scar over a period of months. Hence and formally, the diagnosis of pulmonary infarction cannot be confirmed upon diagnosis of acute PE. Little is known of the impact and relevance of pulmonary infarction in acute PE, and whether specific management strategies should be applied to prevent and/or treat complications such as pain, pneumonia or post-PE syndrome. In this review we will summarize current knowledge on the pathophysiology, epidemiology, diagnosis and prognosis of pulmonary infarction in the setting of acute PE. We highlight the need for dedicated studies to overcome the current knowledge gaps.

Computed tomography appearances of the lung parenchyma in pulmonary hypertension

Computed tomography (CT) is a valuable tool in the workup of patients under investigation for pulmonary hypertension (PH) and may be the first test to suggest the diagnosis. CT parenchymal lung changes can help to differentiate the aetiology of PH. CT can demonstrate interstitial lung disease, emphysema associated with chronic obstructive pulmonary disease, features of left heart failure (including interstitial oedema), and changes secondary to miscellaneous conditions such as sarcoidosis. CT also demonstrates parenchymal changes secondary to chronic thromboembolic disease and venous diseases such as pulmonary venous occlusive disease (PVOD) and pulmonary capillary haemangiomatosis (PCH). It is important for the radiologist to be aware of the various manifestations of PH in the lung, to help facilitate an accurate and timely diagnosis. This pictorial review illustrates the parenchymal lung changes that can be seen in the various conditions causing PH.

The importance of imaging - Perspectives from redeployment

As the coronavirus disease 2019 (COVID-19) pandemic strains the healthcare system, radiology residents across the United States have become a vital part of the redeployed workforce. Through a series of four cases of COVID-19 patients encountered on the wards, we highlight the insight and unique set of skills redeployed radiology residents possess that are essential to patient care during this crisis. By increasing visibility through active participation on the clinical team, we demonstrate the fundamental role radiology has in the greater field of medicine.

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Radiology residents are an asset to the redeployed workforce and have meaningful contribution to patient care.

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Dynamic imaging rounds became critical in clinical decision-making and expediting appropriate management.

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Redeployment increases the visibility of radiology and highlights the essential role of the radiologist.

Radiological approach to cavitary lung lesions

Cavitary lesions in the lung are not an uncommon imaging encounter and carry a broad differential diagnosis that includes a wide range of pathological conditions from cancers, infections/inflammatory processes to traumatic and congenital lung abnormalities. In this review article, we describe a comprehensive approach for evaluation of cavitary lung lesions and discuss the differential diagnosis in the light of radiological findings.

The "Survived Lung:" An Ultrasound Sign of "Bubbly Consolidation" Pulmonary Infarction

Since the presence of "bubbly consolidation" (central lucencies) on a multi-slice computed tomography pulmonary angiography (MCTPA) is one of the highly specific imaging appearances of infarct secondary to pulmonary embolism, we investigated the ultrasound characteristics of these infarctions. In this study, 118 patients with MCTPA diagnosis of acute pulmonary embolism were enrolled. Pulmonary infarctions were detected in 21 patients (17.7%), of which 10 (47.6%) showed the typical appearance of bubbly consolidation on MCTPA. Lung ultrasound (LUS) was performed to evaluate the characteristics of the infarcts highlighted by MCTPA. The bubbly consolidations showed a very peculiar echographic aspect represented by a triangular hypoechoic consolidation with sharp margins, the absence of air bronchograms and a mostly central roundish hyperechoic area. Air lucencies within a pulmonary infarct is hypothesized to represent the coexistence of aerated non-infarcted lung with the infarcted lung in the same lobule. The ultrasound appearance confirms this hypothesis, so we named the roundish hyperechoic area the "survived lung." This picture was found in all patients with a diagnosis of bubbly consolidation on MCTPA (100%). Χ² between MCTPA and LUS regarding the bubbly consolidation diagnosis is 17.18 (df = 1; p value = 0.00003). Bubbly consolidations show a very typical appearance on LUS. Their detection suggests further investigations (MCTPA or point-of-care multi-organ ultrasonography).

Diagnosis of pulmonary infarction in post-mortem computed tomography and post-mortem magnetic resonance imaging-a technical note

Pulmonary thromboembolism may be accompanied by pulmonary infarction. Even though pulmonary thromboembolism (PTE) is a frequently found cause of death at autopsy, pulmonary infarction accompanying PTE is a less common finding and may therefore easily be misinterpreted as infectious or cancerous lung disease. Appearance of pulmonary infarction in post-mortem imaging and acquisition parameters helping to identify pulmonary infarctions are not described yet. Based on a case of a 50-year-old man who died due to PTE and presented pulmonary infarction, we suggest using a pulmonary algorithm in post-mortem computed tomography combined with post-mortem magnetic resonance imaging of the lungs using conventional T1- and T2-weighted sequences.

Thromboembolic complications of COVID-19: the combined effect of a pro-coagulant pattern and an endothelial thrombo-inflammatory syndrome

Coronavirus disease 2019 (COVID-19) is a newly emerging human infectious disease that has quickly become a worldwide threat to health, mainly causing severe acute respiratory syndrome. In addition to the widely described respiratory syndrome, COVID-19 may cause life-treating complications directly or indirectly related to this infection. Among these, thrombotic complications have emerged as an important issue in patients with COVID-19 infection, particularly in patients in intensive care units. Thrombotic complications due to COVID-19 are likely to occur due to a pro-coagulant pattern encountered in some of these patients or to a progressive endothelial thrombo-inflammatory syndrome causing microvascular disease. In the present authors' experience, from five different hospitals in Italy and the UK, imaging has proved its utility in identifying these COVID-19-related thrombotic complications, with translational clinical relevance. The aim of this review is to illustrate thromboembolic complications directly or indirectly related to COVID-19 disease. Specifically, this review will show complications related to thromboembolism due to a pro-coagulant pattern from those likely related to an endothelial thrombo-inflammatory syndrome.

Evaluation of the Diagnostic Value of Bedside Transthoracic Ultrasonography (TTUS) and Lower Extremity Three-Points Compression Duplex in the Diagnosis of the Pulmonary Embolism

Background:

The present study aimed at evaluating the diagnostic value of lung transthoracic ultrasonography (TTUS) and lower extremity sonography versus computed tomography pulmonary angiography (CTPA) in the diagnosis of pulmonary embolus (PE).

Materials and Methods:

This study was performed on 104 patients with clinically suspected PE. CTPA and D-dimer was performed on all patients. Wells’ deep vein thrombosis criteria (WDVTC) was evaluated and recorded at the patient’s admission. Finally, the results of adding venous and lung sonography scores to the WDVTC with and without the results of D-dimer test were analyzed for predicting the diagnosis of PE.

Results:

There were 104 patients clinically suspected of having a PE and enrolled in the study. A PE was confirmed in 37.5% of this cohort. WDVTC had a sensitivity and specificity of 94.87% and 80.00%, respectively, to predict PE. When adding D-dimer to the WDVTC for patients unlikely to have a PE (WDVTC≤4), the sensitivity and specificity of positive D-dimer in diagnosis of PE were 94.87% and 56.92%, respectively ( P < .001).

Conclusion:

According to these study results, the modification of the WDVTC along with the results of lung TTUS and lower extremity venous sonogram significantly increase the diagnostic power for PE.

Abdominal Manifestations of Sickle Cell Disease

Sickle cell disease is a debilitating hematologic process that affects the entire body. Disease manifestations in the abdomen most commonly result from vaso-occlusion, hemolysis, or infection due to functional asplenia. Organ specific manifestations include those involving the liver (eg, hepatopathy, iron deposition), gallbladder (eg, stone formation), spleen (eg, infarction, abscess formation, sequestration), kidneys (eg, papillary necrosis, infarction), pancreas (eg, pancreatitis), gastrointestinal tract (eg, infarction), reproductive organs (eg, priapism, testicular atrophy), bone (eg, marrow changes, avascular necrosis), vasculature (eg, vasculopathy), and lung bases (eg, acute chest syndrome, infarction). Imaging provides an important clinical tool for evaluation of acute and chronic disease manifestations and complications. In summary, there are multifold abdominal manifestations of sickle cell disease. Recognition of these sequela helps guide management and improves outcomes. The purpose of this article is to review abdominal manifestations of sickle cell disease and discuss common and rare complications of the disease within the abdomen.

Infarct-Like Spindle Cell Carcinoma of the Lung: Clinicopathologic, Immunohistochemical, and Molecular Analysis of 4 Cases

Pulmonary spindle cell carcinoma is a rare and aggressive malignancy that often mimics benign conditions. We report 4 cases that simulate a pulmonary infarction, 2 of which were misdiagnosed. Patients were 3 men and 1 woman, smokers, presenting chest pain. All cases appeared as pleural-based, solitary, and rounded nodules. Patients underwent wedge resections followed by adjuvant chemotherapy (3/4) but died of disease. At histology, lesions consisted of widely necrotic nodules surrounded by organizing fibrosis and pleuritis. Examination and immunostains with pan-cytokeratins and epithelial membrane antigen (EMA) revealed atypical spindle cells encircling necrotic tissue and involving the vascular wall. Positive staining with PD-L1 was noted. Molecular analysis showed KRAS (2/4) and TP53 (1/4) mutations, whereas EGFR, ALK, and ROS1 alterations were not detected. Although in a limited series, these cases further evidence the treacherous appearance of spindle cell carcinomas and the need for careful attention when examining pulmonary infarcted tissue, thus requiring extensive sampling, meticulous examination of vascular structures, and immunostaining with cytokeratins.

Imaging of Chronic Thromboembolic Disease

Acute pulmonary embolism (PE) is a leading cause of cardiovascular morbidity. The most common long-term complication of acute PE is chronic thromboembolic disease, a heterogenous entity which ranges from asymptomatic imaging sequelae to persistent symptoms. Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease that can develop in this population and represents the only treatable type of pulmonary hypertension. Recognition of the characteristic findings of chronic pulmonary embolism and CTEPH provides not only diagnostic information, but is also crucial for guiding therapy. The present state-of-the-art review focuses on the multimodality imaging features of chronic pulmonary embolism. Detailed description and illustrations of relevant imaging findings will be demonstrated for ventilation/perfusion (V/Q) scan, CT scan and Dual-Energy CT and MRI and features that distinguish chronic PE from common imaging mimics.

A case of pulmonary infarction induced by undiagnosed HIV

A 25-year-old Chinese man visited our institution due to fever and left chest pain. A chest CT showed infiltrative shadows with pleural effusion. Despite antibiotics treatment, his symptoms gradually worsened. The contrast CT showed deterioration of infiltrative shadows with thromboembolism in pulmonary arteries, suggesting pulmonary infarction. Thereafter, his HIV test turned out to be positive. His symptoms and radiological findings improved after initiation of an anticoagulant therapy. No known risk factors for thromboembolism were identified except HIV infection. The possibility of pulmonary thrombosis should be noted when the HIV patient with acute chest pain and pneumonia-like infiltrative shadow is seen.

Incidence and morphological characteristics of the reversed halo sign in patients with acute pulmonary embolism and pulmonary infarction undergoing computed tomography angiography of the pulmonary arteries

OBJECTIVE

To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS.

METHODS

We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients).

RESULTS

Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS.

CONCLUSIONS

A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Clinical Phenotype of a First Unprovoked Acute Pulmonary Embolism Associated with Antiphospholipid Antibody Syndrome

BACKGROUND

Antiphospholipid antibody syndrome (APS), an important cause of acquired thrombophilia, is diagnosed when vascular thrombosis or pregnancy morbidity occurs with persistently positive antiphospholipid antibodies (aPL). APS is a risk factor for unprovoked recurrence of pulmonary embolism (PE). Performing laboratory testing for aPL after a first unprovoked acute PE is controversial. We investigated if a specific phenotype existed in patients with unprovoked with acute PE, suggesting the need to evaluate them for APS.

METHODS

We retrospectively reviewed patients with PE and APS (n=24) and those with unprovoked PE with aPL negative (n=44), evaluated 2006-2016 at the Asan Medical Center. We compared patient demographics, clinical manifestations, laboratory findings, and radiological findings between the groups.

RESULTS

On multivariate logistic regression analysis, two models of independent risk factors for APS-PE were suggested. Model I included hemoptysis (odds ratio [OR], 12.897; 95% confidence interval [CI], 1.025-162.343), low PE severity index (OR, 0.948; 95% CI, 0.917-0.979), and activated partial thromboplastin time (aPTT; OR, 1.166; 95% CI, 1.040-1.307). Model II included age (OR, 0.930; 95% CI, 0.893-0.969) and aPTT (OR, 1.104; 95% CI, 1.000-1.217).

CONCLUSION

We conclude that patients with first unprovoked PE with hemoptysis and are age <40; have a low pulmonary embolism severity index, especially in risk class I-II; and/or prolonged aPTT (above 75th percentile of the reference interval), should be suspected of having APS, and undergo laboratory testing for aPL.

Dynamics of CT visible pleural effusion in patients with pulmonary infarction

Background Pleural effusion remains largely unexplored in patients with pulmonary embolism and concurrent pulmonary infarction. The aim of the study was to investigate the relationship between the size of pulmonary infarction and pleural effusion as well as the time course of pleural effusion in patients with pulmonary infarction. Patients and methods Data from 103 patients with pulmonary infarction was retrospectively analysed along with patient comorbidities, size of pulmonary infarction, presence and size of pleural effusion with the time between the onset of clinical symptoms of pulmonary infarction and CT study. Results Assessment of possible correlations between the size of pulmonary infarction and age revealed a significant negative correlation. There was a highly significant difference (p = 0.005) in the mean size of pulmonary infarction in patients with effusion (34.5 cm3) compared to those without it (14.3 cm3), but the size of the effusion had no correlation with the size of pulmonary infarction. The size of the effusion peaked between 4th-5th day after the onset of clinical symptoms of pulmonary infarction. In the first 5 days after the onset of clinical symptoms of pulmonary infarction a significant correlation was found between the size of the effusion and time with approximation of 1.3 mm/12 h. Conclusions The data shows that patients with a pleural effusion are more likely to have a larger pulmonary infarction than those without it. If present, the effusion can be expected to increase in a relatively slow linear fashion in the first 5 days after the onset of clinical symptoms of pulmonary infarction.

Clinical characteristics of patients with pulmonary infarction - A retrospective review

BACKGROUND

Pulmonary infarction is an infrequent complication of pulmonary embolism. Traditionally, it has been regarded as a sign of worse outcome because ischemia can only occur by the simultaneous failure of all oxygenation sources to the area of infarct, but supporting evidence is limited.

METHODS

We identified 74 cases of pulmonary infarction over 5 years at a single academic center via review of radiographic reports. Contrast-enhanced chest CT scans were examined to confirm evidence of pulmonary infarction, and patient clinical characteristics and imaging results were studied.

RESULTS

Survival to discharge was high (97%). Patients most commonly presented with dyspnea (69%), chest pain (46%), and swelling or pain in the lower extremities (31%), while underlying risk factors included history of malignancy (41%) and surgery within 30 days (24%). Many patients had concurrent cardiovascular (59%) and pulmonary disease (22%). Infarction disproportionately affected the lower lobes.

CONCLUSIONS

Survival after diagnosis of pulmonary infarction is comparable to uncomplicated pulmonary embolism, suggesting that outcome is not worse. While emboli occurred in multiple lobar sites, pulmonary infarction occurred most commonly in the lower lobes, suggesting unique underlying physiological mechanisms in pulmonary infarction development.

[CME: Cavitary Pulmonary Disease – Differential Diagnosis and Diagnostic Work-Up]

Zusammenfassung. Ein kavernierender oder kavitierender Lungenrundherd bzw. eine Lungenkaverne ist die Manifestation einer grossen Bandbreite von pathologischen Prozessen mit Befall der Lunge inklusive entzündlicher, infektiöser und maligner Ätiologien. Gleichzeitig kann das Vorhandensein einer Kaverne im klinischen Kontext helfen, die Differenzialdiagnosen und damit die weiteren Abklärungsschritte einzugrenzen. Wir werden im Folgenden einen Überblick über mögliche Diagnosen und die entsprechenden klinischen und radiologischen Zeichen kavernierender Lungenrundherde darlegen; ein besonderer Fokus wird dabei auf Vaskulitiden gelegt.

Pulmonary infarction secondary to pulmonary embolism: An evolving paradigm

BACKGROUND AND OBJECTIVE

Pulmonary infarction (PI) from pulmonary embolism (PE) remains an entity of unclear aetiology. PI has been thought to occur in elderly patients with cardiopulmonary disease. We hypothesize younger patients without cardiopulmonary comorbidities are at highest risk. Our study aims to characterize PI clinically and radiographically, determine associated risk factors and determine their clinical significance.

METHODS

We conducted a single-centre retrospective review of 367 consecutive patients with PE. Clinical and radiographic data were compared between patients with and without PI using chi-square and F-tests. Univariate and multivariate analyses were performed to evaluate risk factors for PI.

RESULTS

PI occurred in 62 of 367 patients with acute PE (16.9%). Patients with PI were significantly younger (48 ± 20.3 vs 59.6 ± 17.2 years, P < 0.01), with lower pulmonary embolism severity index (PESI) scores (73.7 ± 38.1 vs 91.9 ± 37.5 years, P < 0.01) and endorsed chest pain with significantly higher frequency (65% vs 39%, P < 0.01). There was no significant difference in other clinical symptoms, hospital length of stay or mortality between groups. Presence of radiographic cardiopulmonary disease was significantly lower in patients with PI (emphysema: 5% vs 22%, P = <0.01; aortic atherosclerosis: 23% vs 43%, P = <0.01). In multivariate analysis, age ≤33 (OR 3.5 CI: 1.37-8.95, P < 0.01), chest pain (OR 2.15 CI: 1.15-4.00, P = 0.02) and pleural effusion (OR 2.18 CI: 1.08-4.41, P = 0.03) increased PI risk and presence of emphysema decreased risk (OR 0.21 CI: 0.06-0.70, P = 0.01).

CONCLUSION

Younger patients without cardiopulmonary comorbidities are at highest risk of PI. Chest pain and pleural effusion significantly increased risk of PI while presence of radiographic emphysema reduced risk.

Fan-shaped ground-glass opacity (GGO) as a premonitory sign of pulmonary infarction: a case report

Radiological findings of pulmonary infarction have been well characterized mainly in established infarction. However, the early course CT appearance of patients who develop pulmonary infarction has not yet been fully elucidated. A 50-year-old female with a history of postmenopausal hormone replacement therapy (HRT) presented with dry cough and high-resolution computed tomography (HRCT) findings of fan-shaped segmental ground-glass opacity (GGO) in the right lower lobe. As the parenchymal density in the GGO gradually enlarged over a period of 4 weeks in spite of antibiotic treatment, the patient was referred to our hospital on clinical suspicion of bronchioloalveolar cell carcinoma. However, the pathological findings of a transbronchial biopsy of the lesion were compatible with pulmonary infarction. After an endoscopic examination, the typical CT appearance of established pulmonary infarction was observed. Moreover, enhanced CT detected an intraluminal filling defect in the right lower lobe artery suggesting peripheral pulmonary emboli. Our case was a peripheral pulmonary infarction probably induced by HRT, and suggested that fan-shaped GGO may be a premonitory sign of pulmonary infarction.

Morphological characteristics of the reversed halo sign that may strongly suggest pulmonary infarction

AIM

To analyse the morphological characteristics of the reversed halo sign (RHS) on unenhanced chest computed tomography (CT), which raise suspicion of pulmonary infarction (PI) associated with pulmonary embolism (PE), and to compare these characteristics with those observed in the RHS caused by other diseases.

MATERIAL AND METHODS

CT images of 145 patients (250 RHSs) were reviewed retrospectively. Sixty-four patients had the RHS due to PI; in 81 immunocompetent patients, the RHS was caused by alternative pulmonary diseases. All PIs secondary to PE were confirmed at CT angiography. Other diagnoses were confirmed using published criteria. Two independent thoracic radiologists, who were blinded patient demographics, clinical data, and final diagnoses, analysed the morphological CT features of the RHSs.

RESULTS

Seventy-four RHSs were found in the PI group and 176 RHSs in the group of other diseases. Single RHSs were associated more frequently with PI compared with the group without PIs; three or more lesions were seen only in patients with other diseases. Low-attenuation areas inside the RHS, with or without reticulation, were observed in 94.59% of PI-associated lesions, and in no patient in the group without PI (p<0.001). Subpleural involvement (p<0.001) and lower-lung predominance (p=0.001) were also associated more frequently with PI. Pleural effusion was observed in 64.06% of patients with PI and in only 6.17% of those with other diseases (p<0.001).

CONCLUSIONS

A single RHS with low-attenuation areas inside the halo, with or without reticulation, is highly suggestive of PI. Lower-lung predominance and pleural effusion also suggest PI.

Imaging in Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the potentially curable causes of pulmonary hypertension and is definitively treated with pulmonary thromboendartectomy. CTEPH can be overlooked, as its symptoms are nonspecific and can be mimicked by a wide range of diseases that can cause pulmonary hypertension. Early diagnosis of CTEPH and prompt evaluation for surgical candidacy are paramount factors in determining future outcomes. Imaging plays a central role in the diagnosis of CTEPH and patient selection for pulmonary thromboendartectomy and balloon pulmonary angioplasty. Currently, various imaging tools are used in concert, with techniques such as computed tomography (CT) and conventional pulmonary angiography providing detailed structural information, tests such as ventilation-perfusion (V/Q) scanning providing functional data, and magnetic resonance imaging providing a combination of morphologic and functional information. Emerging techniques such as dual-energy CT and single photon emission computed tomography-CT V/Q scanning promise to provide both anatomic and functional information in a single test and may change the way we image these patients in the near future. In this review, we discuss the roles of various imaging techniques and discuss their merits, limitations, and relative strengths in depicting the structural and functional changes of CTEPH. We also explore newer imaging techniques and the potential value they may offer.

Infected pulmonary infarction. Case report

Introducción: el infarto pulmonar ocurre entre un 29 y un 32% de pacientes con tromboembolismo pulmonar (TEP). Por su parte, la infección de un infarto pulmonar complica aproximadamente del 2 al 7% de los casos, lo que hace que el infarto pulmonar infectado sea una entidad poco frecuente.Descripción del caso: mujer de 49 años con dolor pleurítico en hemitórax izquierdo, irradiado a región dorsal, asociado a disnea y edema doloroso de miembro inferior izquierdo de dos días de evolución. Dos semanas antes de su ingreso la paciente sufrió trauma de rodilla izquierda, el cual que requirió intervención quirúrgica; sin embargo, por motivos desconocidos, no recibió profilaxis anti trombótica. En el examen físico se encontró taquicardia, taquipnea y edema doloroso con eritema en pierna izquierda. Al existir alta sospecha de tromboembolia pulmonar se inició anticoagulación y se solicitó angiotomografía de tórax, con la cual fue posible confirmar el diagnóstico. Durante su evolución, la paciente experimentó signos de respuesta inflamatoria sistémica, deterioro respiratorio. Se realizó tomografía de control sugestiva de infarto pulmonar infectado. Se inició antibiótico y la paciente mejoró de forma progresiva; después de esta mejora, fue dada de alta para continuar anticoagulación y seguimiento ambulatorios.Conclusiones: el infarto pulmonar es una complicación frecuente en pacientes con TEP. Por lo tanto, debe sospecharse infarto pulmonar infectado en pacientes con deterioro clínico y respuesta inflamatoria sistémica. La diferencia radiológica entre infarto pulmonar y neumonía no es fácil de identificar, su enfoque diagnóstico es clínico y el tratamiento anticoagulante y antimicrobiano debe iniciarse de manera oportuna. 

Historical Evolution of Imaging Techniques for the Evaluation of Pulmonary Embolism

As we celebrate the 100th anniversary of the founding of the Radiological Society of North America (RSNA), it seems fitting to look back at the major accomplishments of the radiology community in the diagnosis of pulmonary embolism. Few diseases have so consistently captured the attention of the medical community. Since the first description of pulmonary embolism by Virchow in the 1850s, clinicians have struggled to reach a timely diagnosis of this common condition because of its nonspecific and often confusing clinical picture. As imaging tests started to gain importance in the 1900s, the approach to diagnosing pulmonary embolism also began to change. Rapid improvements in angiography, ventilation-perfusion imaging, and cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance imaging have constantly forced health care professionals to rethink how they diagnose pulmonary embolism. Needless to say, the way pulmonary embolism is diagnosed today is distinctly different from how it was diagnosed in Virchow's era; and imaging, particularly CT, now forms the cornerstone of diagnostic evaluation. Currently, radiology offers a variety of tests that are fast and accurate and can provide anatomic and functional information, thus allowing early diagnosis and triage of cases. This review provides a historical journey into the evolution of these imaging tests and highlights some of the major breakthroughs achieved by the radiology community and RSNA in this process. Also highlighted are areas of ongoing research and development in this field of imaging as radiologists seek to combat some of the newer challenges faced by modern medicine, such as rising health care costs and radiation dose hazards.

Pictorial essay of radiological features of benign intrathoracic masses

With increased exposure of patients to routine imaging, incidental benign intrathoracic masses are frequently recognized. Most have classical imaging features, which are pathognomonic for their benignity. The aim of this pictorial review is to educate the reader of radiological features of several types of intrathoracic masses. The masses are categorized based on their location/origin and are grouped into parenchymal, pleural, mediastinal, or bronchial. Thoracic wall masses that invade the thorax such as neurofibromas and lipomas are included as they may mimic intrathoracic masses. All examples are illustrated and include pulmonary hamartoma, pleural fibroma, sarcoidosis, bronchial carcinoid, and bronchoceles together with a variety of mediastinal cysts on plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI). Sometimes a multimodality approach would be needed to confirm the diagnosis in atypical cases. The study would include the incorporation of radionuclide studies and relevant discussion in a multidisciplinary setting.

Predictors of Pulmonary Infarction

In the setting of acute pulmonary embolism (PE), pulmonary infarction is deemed to occur primarily in individuals with compromised cardiac function.The current study was undertaken to establish the prevalence of pulmonary infarction in patients with acute PE, and the relationship between infarction and: age, body height, body mass index (BMI), smoking habits, clot burden, and comorbidities.The authors studied prospectively 335 patients with acute PE diagnosed by computed tomographic angiography (CT) in 18 hospitals throughout central Italy. The diagnosis of pulmonary infarction on CT was based on Hampton and Castleman's criteria (cushion-like or hemispherical consolidation lying along the visceral pleura). Multivariable logistic regression was used to model the relationship between covariates and the probability of pulmonary infarction.The prevalence of pulmonary infarction was 31%. Patients with infarction were significantly younger and with significantly lower prevalence of cardiovascular disease than those without (P < 0.001). The frequency of infarction increased linearly with increasing height, and decreased with increasing BMI. In logistic regression, the covariates significantly associated with the probability of infarction were age, body height, BMI, and current smoking. The risk of infarction grew with age, peaked at approximately age 40, and decreased afterwards. Increasing body height and current smoking were significant amplifiers of the risk of infarction, whereas increasing BMI appeared to confer some protection.Our data indicate that pulmonary infarction occurs in nearly one-third of the patients with acute PE. Those with infarction are often young and otherwise healthy. Increasing body height and active smoking are predisposing risk factors.

Multidetector CT of pulmonary cavitation: filling in the holes

Pulmonary cavitation causes significant morbidity and mortality. Early diagnosis of the presence and aetiology of a cavity is therefore crucial in order to avoid further demise in both the localized pulmonary and systemic disorders that may manifest with pulmonary cavity formation. Multidetector CT has become the principal diagnostic technique for detecting pulmonary cavitation and its complications. This review provides an overview of the aetiologies and their imaging findings using this technique. Combining a literature review with case illustration, a synopsis of the different imaging features and constellations is provided, which may suggest a particular cause and aid the differentiation from diseases with similar findings.

Reversed halo sign in pulmonary infarction with tumor emboli: a case report

We describe the case of a 79-year-old woman with pulmonary infarction due to tumor emboli whose high-resolution CT (HRCT) scan demonstrated the reversed halo sign. The patient had gastric cancer and died because of cancer-related cerebral infarction. On autopsy, the central ground-glass area of the reversed halo sign on HRCT corresponded to pulmonary edema associated with alveolar septal capillary metastasis, whereas the peripheral ring-like consolidation consisted of a hemorrhagic infarct with tumor emboli. The present case is important because a detailed pathologic correlation with this unique HRCT appearance was revealed.

[Cavitating pulmonary infarcts revealing thromboembolic pulmonary hypertension]

Several etiologies are involved in the pathogenesis of cavitating pulmonary disease including neoplastic, infectious or inflammatory processes. Another is pulmonary infarction associated with venous thromboembolism. The lung cavities tend to be located peripherally and are the result of pulmonary embolism. We report the case of a woman with chronic thromboembolic pulmonary hypertension (CTEPH), associated with familial thrombophilia, revealed by cavitating pulmonary infarcts. CTEPH is sometimes diagnosed during an episode of recurrent pulmonary embolism following previously unnoticed lesions. Thrombophilias such as isolated elevated factor VIII are risk factors for CTEPH.

Clinical relevance of pulmonary infarction in patients with pulmonary embolism

INTRODUCTION

Data regarding the clinical relevance of pulmonary infarction (PI) in patients with pulmonary embolism (PE) are lacking. The aim of this study was to investigate the clinical features of PE patients with PI and the prognostic role of PI for PE patients.

MATERIALS AND METHODS

Based on computed tomography scan, 509 patients with PE were divided into two groups, the infarction group (n=45) and the non-infarction group (n=464). A variety of clinical parameters were compared between the two groups.

RESULTS

In the infarction group, the largest pulmonary arteries involved by emboli were central rather than peripheral and more proximal as compared to the non-infarction group (p=0.01 and p<0.03, respectively). Thrombolytic agents tended to be more frequently administered in the infarction group (13.3% [n=6] versus 6.3% [n=29], p=0.07). In-hospital mortality, PE-related deaths, and the recurrence rate of PE did not differ between the two groups.

CONCLUSIONS

The present study did not demonstrate that PI is a prognostic indicator of recurrence and mortality in PE patients. We suggest the possibility that blood clot burden is greater in PE patients with PI, although PI by itself occurs in small pulmonary arteries.