Thoracic and Cardiovascular Imaging Manifestations of Lupus

Systemic lupus erythematosus (SLE), commonly referred to as lupus, is a widely prevalent chronic autoimmune disease that can affect any organ system in the body. Although the pathogenesis of this disease is rather complex and poorly understood, ultimately there is an overproduction of multiple self-reactive antinuclear antibodies. These autoantibodies are one of the laboratory hallmarks of the diagnosis and disease activity of SLE. Lupus has a myriad of symptoms and imaging manifestations. Serositis, one of the most common manifestations of the disease, usually occurs with pleural or pericardial effusion with or without associated serosal inflammatory changes. The pulmonary manifestations are heterogeneous, with mostly acute (eg, diffuse alveolar hemorrhage, acute lupus pneumonitis) and some chronic (eg, fibrosing interstitial lung disease, shrinking lung syndrome) lung findings. Cardiac and vascular manifestations include myocarditis; coronary artery disease, including accelerated atherosclerosis; myocardial infarction; and spontaneous dissections, along with vasculitis, aneurysms, Libman-Sacks endocarditis, and arterial and venous thromboembolism. Although patient history and risk factor assessment have a vital role in diagnosing lupus, familiarity with the imaging manifestations aids radiologists in optimizing patient care, assessing for complications, and uncovering undiagnosed cases of lupus. This fact emphasizes the importance of recognizing the complex multisystem involvement of lupus seen at imaging. In this article, the authors review the thoracic and cardiovascular imaging manifestations of lupus. © RSNA, 2024.

Imaging of unicentric hyaline-vascular variant of Castleman disease: Emphasis on perilesional fat stranding and fatty proliferation

The hyaline-vascular variant of Castleman disease (HVCD) is relatively uncommon and demonstrates no specific clinical or laboratory findings; therefore, its preoperative diagnosis warrants a radiological evaluation. This study aimed to review imaging findings of HVCD, focusing on perilesional fat stranding and fatty proliferation. Patients with a pathologically confirmed HVCD diagnosis who had undergone CT were recruited from five hospitals from January 2000 to March 2023. Three experienced radiologists assessed CT findings, including lesion location, lesion size, calcification, enhanced pattern, feeding vessel visualization, and arterial enhancement. Perilesional fat stranding, fatty proliferation, neighboring fascial thickening, and surrounding lymphadenopathy were the primary targets of analysis. Moreover, the intensities and apparent diffusion coefficient (ADC) values on MRI and the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (PET) were evaluated. This study enrolled 43 patients (mean age 41.3 years ± 14.6 [standard deviation], 23 women). All lesions were well-defined round masses. Calcification and feeding vessels were detected in 21% (9/43) and 86% (36/43) of the patients, respectively. Perilesional fat stranding and fatty proliferation were observed in 44% (19/43) and 19% (8/43), respectively, with fatty proliferation detected only in retroperitoneal HVCD. Neighboring fascial thickening and surrounding lymphadenopathy were identified in 21% and 60%, respectively. The mean ADC value and SUVmax were 0.884 × 10-3 mm2/s and 5.0, respectively. Retroperitoneal HVCD cases with perilesional fatty proliferation demonstrated a higher visceral fat ratio than those without (p = 0.046). Perilesional fat stranding and fatty proliferation were new characteristics of HVCD, especially in retroperitoneal cases.

Clinical Impact of Chronic Pulmonary Aspergillosis in Patients with Nontuberculous Mycobacterial Pulmonary Disease and Role of Computed Tomography in the Diagnosis

Objective Chronic pulmonary aspergillosis (CPA) is an important complication of nontuberculous mycobacterial pulmonary disease (NTM-PD). However, its diagnosis is challenging, as both CPA and NTM-PD present as chronic cavitary disease. The present study evaluated the impact of CPA on the survival of patients with NTM-PD and revealed the key computed tomography findings for a prompt diagnosis. Methods We retrospectively reviewed patients newly diagnosed with NTM-PD in Tenri Hospital (Tenri City, Nara Prefecture, Japan) between January 2009 and March 2018; the patients were followed up until May 2021. Clinical and radiological characteristics were assessed, and patients with CPA were identified. Results A total of 611 patients were diagnosed with NTM-PD. Among them, 38 (6.2%), 102 (17%), and 471 (77%) patients were diagnosed with NTM-PD with CPA, cavitary NTM-PD without CPA, and non-cavitary NTM-PD without CPA, respectively. The 5-year survival rate of the NTM-PD with CPA group (42.8%; 95% confidence interval: 28.7-64.0%) was lower than that of the cavitary NTM-PD without CPA group (74.4%; 95% confidence interval: 65.4-84.6%). A multivariate analysis revealed that fungal balls and cavities with adjacent extrapleural fat were significant predictive factors for NTM-PD with CPA. Conclusion NTM-PD with CPA patients exhibited a worse prognosis than cavitary NTM-PD without CPA patients. Therefore, an unerring diagnosis of CPA is essential for managing patients with NTM-PD. Computed tomography findings, such as fungal balls and cavities with adjacent extrapleural fat, may be valuable diagnostic clues when CPA is suspected in patients with NTM-PD.

Mesotheliomas and Benign Mesothelial Tumors: Update on Pathologic and Imaging Findings

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A, and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A-, NF2-, and BAP1-altered mesotheliomas are under consideration. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Role of Chest Computed Tomography in Patients Hospitalized with Community-Acquired Complicated Parapneumonic Effusion or Empyema: Role of CT in Parapneumonic Effusion

BACKGROUND

Data regarding predictors of the outcome in patients with community-acquired complicated parapneumonic effusion (CPPE) or empyema are insufficient. The aim of the present study was to investigate the prognostic factors in these patients.

METHODS

Patients with community-acquired pneumonia (CAP) were classified into a CPPE or empyema group and a control group. The patients with CPPE or empyema were further divided into longer and shorter length of stay (LOS) groups, and clinical variables and computed tomographic (CT) findings were compared between the 2 groups.

RESULTS

Of outcome variables, LOS was significantly longer in the CPPE or empyema group than in the control group (13 days [interquartile range, 10‒17 days] versus 8 days [6‒12 days], p < 0.001), whereas 30-day mortality and in-hospital mortality were not significantly different between the 2 groups. Patients with CPPE or empyema were divided into shorter LOS (<14 days) and longer LOS (≥14 days) groups. Pneumonia severity index (PSI) class IV‒V (odds ratio [OR], 2.79; 95% confidence interval [CI]: 1.35, 5.76; p = 0.006), increased attenuation of extrapleural fat (OR, 2.26; 95% CI: 1.06, 4.80; p = 0.034), and pleural microbubbles (OR 3.93; 95% CI: 1.03, 14.98; p = 0.045) were independent predictors for prolonged LOS in CAP patients with CPPE or empyema.

CONCLUSIONS

Increased attenuation of extrapleural fat and pleural microbubbles assessed with CT and PSI class IV‒V independently predicted prolonged LOS in CAP patients with CPPE or empyema. These findings may be helpful to identify patients who need more intensive evaluation and intervention.

Computed tomography findings, temporal course, and clinical relevance of subpleural pulmonary interstitial emphysema in patients with pneumomediastinum

Background

Subpleural pulmonary interstitial emphysema is defined as the air in the subpleural portion of the lung, and the clinical relevance is not well understood.

Purpose

to evaluate the frequency, temporal course, risk factors, and clinical significance of subpleural pulmonary interstitial emphysema (PIE) in patients with pneumomediastinum resulting from ruptured alveoli and other causes.

Material and Methods

This was a retrospective study of 130 patients with pneumomediastinum on CT between January 2009 and December 2019 at 2 hospitals. Patients were divided into 3 groups as follows: spontaneous pneumomediastinum (n = 101), pneumomediastinum due to blunt trauma (n = 16), and pneumomediastinum due to another known cause (n = 13). The frequencies of radiographic features (subpleural PIE, peribronchovascular PIE, pneumothorax, pulmonary fibrosis, and emphysematous changes) between the 3 groups were compared by the χ² or Kruskal–Wallis test. Odds ratios were calculated to evaluate candidate risk factors for subpleural and peribronchovascular PIE.

Results

Subpleural PIE was observed in 0%, 15.8%, and 31.3% of patients with pneumomediastinum due to another cause, spontaneous mediastinum, and blunt trauma, respectively. In most patients, subpleural PIE resolved spontaneously (85.7% within 8 days). Two patients with pulmonary fibrosis showed recurrent subpleural PIE on follow-up. Young age showed increased risk for subpleural PIE (odds ratio [OR] 0.9, 95% confidence interval [CI] 0–0.99).

Conclusion

Subpleural PIE was only detected in patients with pneumomediastinum due to ruptured alveoli and resolved spontaneously and rapidly. Subpleural PIE may be one route the air from ruptured alveoli to the mediastinum.

Intercostal Nerve Block Using an Innovative Intraneedle Ultrasound Transducer: A Proof-of-Concept study

Intercostal nerve block is a widely used and effective approach to providing regional anesthesia in the thoracic region for pain relief. However, during ultrasound-guided intercostal nerve block, inaccurate identification of the anatomic structures or suboptimal positioning of the needle tip may result in complications and blockade failure. In this study, we designed an intraneedle ultrasound (INUS) system and validated its efficacy in identifying anatomic structures relevant to thoracic region anesthesia. The 20-MHz INUS transducer comprised a single lead magnesium niobate-lead titanate crystal, and gain was set to 20 dB. It fit into a regular 18G needle and emitted radiofrequency-mode ultrasound signals at 1 mm from the needle tip. One hundred intercostal punctures were performed in 10 piglets. Intercostal spaces were identified by surface ultrasound or palpation and located by inserting and advancing the INUS transducer needle until the appropriate anatomy was identified. Blockade success was defined by ideal saline and dye spreading and confirmed by dissection. The pleura had a distinctive ultrasound signal, and successful detection of the intercostal muscles, endothoracic fascia and double-layered parietal and visceral pleura was achieved in all 100 puncture attempts. INUS allows real-time identification of intercostal structures and facilitates successful intercostal nerve blocks.

"Multimodality imaging of the extrapleural space lesions"

Extrapleural space (EPS) is a potential space between the outer layer of the parietal pleura and the inner layer of the chest wall and the diaphragm. Many different pathologies including chronic inflammatory conditions, infections, trauma, neoplastic disease (both benign and malignant) as well as many infiltrative disorders can involve the EPS. It is one of the frequently overlooked entity on imaging due to relative lack of understanding of the anatomy and the imaging appearances of the diseases localized to this space. The knowledge of the EPS is essential for the radiologists as the pathologies which involve the EPS may require different treatment approach compared to pleural or parenchymal lung disease. Additionally, the EPS involvement may influence the staging and treatment planning for chest malignancies. In this review, we give an overview of the anatomy and various pathologies involving EPS, utility of different imaging modalities in the evaluation of EPS lesions with emphasis on cross sectional imaging and emerging technologies like spectral CT and its role in recognizing the imaging features which enable specific diagnosis of various pathologies.

Late Diagnosis of a Large Extrapleural Hematoma in a Patient With Stanford Type B Aortic Dissection: A Case Report and Review of Literature

Acute aortic dissection is a rare but catastrophic condition. When the dissection extends through the adventitia, blood can extravasate into the extrapleural or intrapleural spaces, causing an extrapleural hematoma or hemothorax. The early recognition of extrapleural hematoma and distinguishing it from hemothorax is critical because the management of those two entities is different. The authors present a case of a late diagnosis of a large extrapleural hematoma in a patient with Stanford type B acute aortic dissection that required thoracotomy for hematoma evacuation. The patient underwent successful thoracic endovascular aortic repair (TEVAR). Postoperatively, the patient had worsening pulmonary function, with a large fluid collection on imaging that was not drained by the thoracostomy tubes. Surgical exploration revealed a large extrapleural hematoma. Timely recognition of the extrapleural hematoma was key in the patient's clinical management. Without clear radiographic diagnostic features of extrapleural hematoma, unsuccessful drainage of hematoma after insertion of a chest tube may suggest an extrapleural hematoma or a clotted hemothorax. If patients continue to have circulatory or respiratory compromises, prompt surgical exploration should be considered. It is important for clinicians to be aware of extrapleural hematoma in complicated acute aortic dissection, especially when chest tube drainage of an apparent hemothorax is unsuccessful.

Phlegmonous Appearance in the Ipsilateral Paracardiac Fat without Paracardiac Lymph Node Enlargement on Chest CT Favors the Diagnosis of Pleural Tuberculosis over Malignant Pleural Effusion

This study investigated the potential role of paracardiac fat stranding (FS) interspersed with multiple fluid collections (FC) as a clue to differentiate between pleural tuberculosis (pleural TB) and malignant pleural effusion (MPE). The authors retrospectively analyzed chest computed tomography (CT) findings of 428 patients, 351 with pleural TB and 77 with MPE, focusing on the paracardiac fat, and level of pleural adenosine deaminase (ADA) and blood C-reactive protein (CRP). Two radiologists independently evaluated the chest CT findings regarding the paracardiac fat pad ipsilateral to the effusion, including FS, FC, phlegmonous appearance (a combination of the FS and multiple FC), and the presence of lymph node enlargement (>1 cm in short axis diameter). There were significant differences between patients with pleural TB and those with MPE with respect to the prevalence of phlegmonous appearance in the ipsilateral paracardiac fat (47.6% and 10.4%, p < 0.001, OR = 7.8; 95% CI 3.7–16.8) and paracardiac lymph node enlargement (1.4% and 19.5%, p < 0.001, OR = 0.06; 95% CI 0.02–0.2) on CT. In contrast, there was no difference in the prevalence of isolated FS or multiple FC within the ipsilateral paracardiac fat between the two groups. Median pleural ADA and serum CRP level were higher in patients with pleural TB accompanied by phlegmonous appearance in paracardiac fat compared to those without that appearance (ADA: median 104 IU/L versus 90 IU/L, p < 0.001; CRP: 6.5 mg/dL versus 4.2 mg/dL, p < 0.001). In conclusion, phlegmonous appearance in the ipsilateral paracardiac fat without paracardiac lymph node enlargement on chest CT favors a diagnosis of pleural TB over MPE.

Thoracic abnormal air collections in patients in the intensive care unit: radiograph findings correlated with CT

An abnormal collection of air in the thorax is one of the most common life-threatening events that occurs in the intensive care unit. Patient management differs depending on the location of the air collection; therefore, detecting abnormal air collection and identifying its exact location on supine chest radiographs is essential for early treatment and positive patient outcomes. Thoracic abnormal air collects in multiple thoracic spaces, including the pleural cavity, chest wall, mediastinum, pericardium, and lung. Pneumothorax in the supine position shows different radiographic findings depending on the location. Many conditions, such as skin folds, interlobar fissure, bullae in the apices, and air collection in the intrathoracic extrapleural space, mimic pneumothorax on radiographs. Additionally, pneumopericardium may resemble pneumomediastinum and needs to be differentiated. Further, some conditions such as inferior pulmonary ligament air collection versus a pneumatocele or pneumothorax in the posteromedial space require a differential diagnosis based on radiographs. Computed tomography (CT) is required to localize the air and delineate potential etiologies when a diagnosis by radiography is difficult. The purposes of this article are to review the anatomy of the potential spaces in the chest where abnormal air can collect, explain characteristic radiographic findings of the abnormal air collection in supine patients with illustrations and correlated CT images, and describe the distinguishing features of conditions that require a differential diagnosis. Since management differs based on the location of the air collection, radiologists should try to accurately detect and identify the location of air collection on supine radiographs.

Imaging of thoracic hernias: types and complications

Thoracic hernias are characterised by either protrusion of the thoracic contents outside their normal anatomical confines or extension of the abdominal contents within the thorax. Thoracic hernias can be either congenital or acquired in aetiology. They can occur at the level of the thoracic inlet, chest wall or diaphragm. Thoracic hernias can be symptomatic or fortuitously discovered on imaging obtained for other indications. Complications of thoracic hernias include incarceration, trauma and strangulation with necrosis. Multiple imaging modalities are available to evaluate thoracic hernias. Radiographs usually offer the first clue to the diagnosis. Upper gastrointestinal radiography can identify bowel herniation and associated complications. CT and occasionally MR can be useful for further evaluation of these abnormalities, accurately identifying the type of hernia, its contents, associated complications, and provide a roadmap for surgical planning. In this article, we review the different types of thoracic hernias and the role of imaging in the evaluation of these hernias. TEACHING POINTS: • Protrusion of lung contents beyond the anatomic confines of the thorax constitutes a hernia. • Complications of thoracic hernias include incarceration, trauma and strangulation with necrosis. • Multiple imaging modalities are available to evaluate thoracic hernias. • CT is the imaging modality of choice for identifying thoracic hernias and their complications. • Imaging can provide a roadmap for surgical planning.