Pattern-Based Differential Diagnosis in Pulmonary Vasculitis Using Volumetric CT

Lung Involvement in Pulmonary Vasculitis: A Radiological Review

Pulmonary vasculitis identifies a heterogeneous group of diseases characterized by inflammation, damage and necrosis of the wall of pulmonary vessels. The most common approach to classify vasculitis is according to etiology, therefore dividing them into primary and secondary, with a further sub-classification of primary vasculitis based on the size of the affected vessels (large, medium, and small). Pulmonary involvement is frequently observed in patients with systemic vasculitis and radiological presentation is not pathognomonic, but may vary between diseases. The main findings using high-resolution computed tomography (HRCT) include small vessel wall thickening, nodular lesions, cavitary lesions, reticular opacities, ground-glass opacities (GGO), consolidations, interlobular septal thickening, tracheobronchial stenosis, and aneurysmal dilatation of pulmonary arteries, with or without pleural effusion. Radiological diagnosis alone is difficult since signs and symptoms of lung vessel involvement are often non-specific and might overlap with other conditions such as infections, connective tissue diseases and neoplasms. Therefore, the aim of this review is to describe the most common radiological features of lung involvement in pulmonary vasculitis so that, alongside detailed clinical history and laboratory tests, a prompt diagnosis can be performed.

Behçet's Disease: A Radiological Review of Vascular and Parenchymal Pulmonary Involvement

Behcet's disease (BD) is a chronic systemic inflammatory disorder characterized by underlying chronic vasculitis of both large- and small-caliber vessels. Thoracic involvement in BD can occur with various types of manifestations, which can be detected with contrast-enhanced MSCT scanning. In addition, MR can be useful in diagnosis. Characteristic features are aneurysms of the pulmonary arteries that can cause severe hemoptysis and SVC thrombosis that manifests as SVC syndrome. Other manifestations are aortic and bronchial artery aneurysms, alveolar hemorrhage, pulmonary infarction, and rarely pleural effusion. Achieving the right diagnosis of these manifestations is important for setting the correct therapy and improving the patient's outcome.

Imaging of COVID-19 simulators

Background

Coronavirus (COVID-19) pneumonia emerged in Wuhan, China, in December 2019. It was highly contagious spreading all over the world, with a rapid increase in the number of deaths. The reported cases have reached more than 14 million with more than 600,000 deaths around the world. So, the pandemic of COVID-19 became a surpassing healthcare crisis with an intensive load on the healthcare resources.

In this study, the aim was to differentiate COVID-19 pneumonia from its mimickers as atypical infection, interstitial lung diseases, and eosinophilic lung diseases based on CT, clinical, and laboratory findings.

Results

This retrospective study included 260 patients, of which 220 were confirmed as COVID-19 positive by two repeated RT-PCR test and 40 were classified as non-COVID by two repeated negative RT-PCR test or identification of other pathogens, other relevant histories, or clinical findings.

In this study, 158 patients were male (60.7 %) and 102 patients were female (39.3%). There was 60.9% of the COVID-19 group were male and 39.1% were female. Patients in the non-COVID group were significantly older (the mean age was 46.4) than those in the confirmed COVID-19 group (35.2y). In the COVID-19 group, there was exposure history to positive cases in 84.1% while positive exposure history was 20% in the non-COVID group.

Conclusion

The spectrum of CT imaging findings in COVID-19 pneumonia is wide that could be contributed by many other diseases making the interpretation of chest CTs nowadays challenging to differentiate between different diseases having the same signs and act as deceiving simulators in the era of COVID-19.

MR imaging findings of musculoskeletal involvement in microscopic polyangiitis: a comparison with inflammatory myopathy

OBJECTIVE

The purpose of this study was to evaluate the importance of MR imaging findings of musculoskeletal involvement of the lower limbs in diagnosing microscopic polyangiitis (MPA) vs polymyositis (PM) or dermatomyositis (DM).

MATERIALS AND METHODS

This study included 13 patients diagnosed with MPA clinically and through histologically, and 38 diagnosed with PM/DM, who underwent MR imaging of the lower limbs prior to treatment. Axial and coronal short tau inversion recovery (STIR) images were reviewed retrospectively.

RESULTS

The sites affected by MPA were the lower legs in six (46%) patients and the thighs in seven (54%). Intramuscular hyperintensity and fascial hyperintensity were observed in all cases of MPA (100%). Fascial hyperintensity was more frequently encountered in MPA than in PM/DM (100% vs. 45%, p < 0.01). As the predominantly involved sites, the fascial regions were more frequently affected by MPA than by PM/DM (77% vs. 18%, p < 0.01). Diffuse subcutaneous fat hyperintensity was more frequently observed in MPA than in PM/DM (100% vs. 16%, p < 0.01). However, no significant differences in intramuscular hyperintensity (100% vs. 97%, p = 0.745) and subcutaneous fat hyperintensity (54% vs. 50%, p = 0.533) were found between MPA and PM/DM.

CONCLUSION

Intramuscular hyperintensity and fascial hyperintensity have always been observed in MPA, and the predominantly affected sites were usually the fascial regions. Compared with PM/DM, fascial hyperintensity and diffuse subcutaneous fat hyperintensity were more frequent in MPA.

Life-Threatening Hemoptysis

Life-threatening hemoptysis (LTH) is any amount of hemoptysis that causes significant hemodynamic decompensation or respiratory distress which may lead to death if left untreated. While the amount of hemoptysis that qualifies as massive hemoptysis has continued to be debated, any amount between 100 to 1,000 mL/day is considered significant. Up to 15% cases of hemoptysis are LTH and need urgent life-saving intervention. Understanding of pulmonary vascular anatomy is of paramount importance to manage LTH. The goal of treatment lies in airway protection, appropriate oxygenation, and prevention of exsanguination. Once the airway is stabilized, a quick diagnosis and control of bleeding site is targeted. This chapter highlights current practices and approach to LTH including medical management, bronchoscopic approach, and advanced therapies such as bronchial artery embolization and surgical resection. We review situations, such as bronchiectasis, vascular malformation, diffuse alveolar hemorrhage, and tracheostomy bleed and specific approach to management of these conditions in a systematic and evidence-based manner.

Pulmonary arteries: imaging of pulmonary embolism and beyond

The pulmonary arteries are not just affected by thrombus. Various acquired and congenital conditions can also affect the pulmonary arteries. In this review we discuss cross sectional imaging modalities utilized for the imaging of the pulmonary arteries. Acquired pulmonary artery entities, including pulmonary artery sarcoma (PAS), vasculitis, aneurysm, and arteriovenous malformations, and congenital anomalies in adults, including proximal interruption of the pulmonary artery, pulmonary sling, pulmonary artery stenosis, and idiopathic dilatation of the pulmonary trunk, are also discussed. An awareness of these entities and their imaging findings is important for radiologists interpreting chest imaging.

Interstitial lung diseases in dogs and cats part II: Known cause and other discrete forms

In addition to idiopathic interstitial pneumonias, interstitial lung diseases (ILDs) can occur secondary to known causes or be classified as discrete syndromes. Also known as diffuse parenchymal lung diseases, the ILDs represent a heterogenous group of non-infectious, non-neoplastic disorders characterized by varied patterns of inflammation and fibrosis. Characteristically associated with the true interstitium (i.e. the anatomic space lined by alveolar epithelial cells and capillary endothelial cells and the loose-binding connective tissue), it is important to understand ILDs are associated with pathology of the distal lung parenchyma and thus lesions can be bronchiolocentric or resemble alveolar filling disorders. Injury to the distal lung can occur via inhalation or hematogenous routes. This review will build on a proposed classification scheme adapted from human medicine to describe known cause and discrete forms of ILDs in dogs and cats.

Pulmonary vasculitis: diagnosis and endovascular therapy

Pulmonary vasculitides are caused by a heterogeneous group of diseases with different clinical features and etiologies. Radiologic manifestations depend on the predominant type of vessel involved, which are grouped into large, medium, or small-sized vessels. Diagnosing pulmonary vasculitides is a challenging task, and radiologists play an important role in their management by providing supportive evidence for diagnosis and opportunities for minimally invasive therapy. This paper aims to present a practical approach for understanding the vasculitides that can affect the pulmonary vessels and lungs. We will describe and illustrate the main radiologic findings, discussing opportunities for minimally invasive treatment.

Isolated large vessel pulmonary vasculitis leading to pulmonary artery aneurysm formation: a case report and literature review

Pulmonary artery (PA) vasculitis occurs in association with primary vasculitides—in particular, giant cell arteritis, Takayasu’s arteritis, or Behçet’s disease—or secondary vasculitis as a result of infections or malignancy. However, PA vasculitis in isolation and with concomitant aneurysmal dilation is an unusual finding. We present a rare case of PA aneurysm secondary to isolated PA vasculitis in an asymptomatic patient with no features of systemic vasculitis. This case highlights one of the first cases of PA vasculitis managed with surgical resection alone.

Diagnostic Evaluation of Chronic Thromboembolic Pulmonary Hypertension

Pulmonary hypertension is defined by a mean pulmonary artery pressure greater than 25 mm Hg. Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as pulmonary hypertension in the presence of an organized thrombus within the pulmonary vascular bed that persists at least 3 months after the onset of anticoagulant therapy. Because CTEPH is potentially curable by surgical endarterectomy, correct identification of patients with this form of pulmonary hypertension and an accurate assessment of surgical candidacy are essential to provide optimal care. Patients most commonly present with symptoms of exertional dyspnea and otherwise unexplained decline in exercise capacity. Atypical chest pain, a nonproductive cough, and episodic hemoptysis are observed less frequently. With more advanced disease, patients often develop symptoms suggestive of right ventricular compromise. Physical examination findings are minimal early in the course of this disease, but as pulmonary hypertension progresses, may include nonspecific finding of right ventricular failure, such as a tricuspid regurgitation murmur, pedal edema, and jugular venous distention. Chest radiographs may suggest pulmonary hypertension, but are neither sensitive nor specific for the diagnosis. Radioisotopic ventilation-perfusion scanning is sensitive for detecting CTEPH, making it a valuable screening study. Conventional catheter-based pulmonary angiography retains an important role in establishing the presence and extent of chronic thromboembolic disease. However, computed tomographic and magnetic resonance imaging are playing a growing diagnostic role. Innovative technologies such as dual-energy computed tomography, dynamic contrast-enhanced magnetic resonance imaging, and optical coherence tomography show promise for contributing diagnostic information and assisting in the preoperative characterization of patients with CTEPH.

Pulmonary Vasculitis: Spectrum of Imaging Appearances

Pulmonary vasculitis is a relatively uncommon disorder, usually manifesting as part of systemic vasculitis. Imaging, specifically computed tomography, is often performed in the initial diagnostic workup. Although the findings in vasculitis can be nonspecific, they can provide important clues in the diagnosis, and guide the clinical team toward the right diagnosis. Radiologists must have knowledge of common and uncommon imaging findings in various vasculitides. Also, radiologists should be able to integrate the clinical presentation and laboratory test findings together with imaging features, so as to provide a meaningful differential diagnosis.

Diseases and Syndromes That Affect the Lungs and the Kidneys: A Radiologic Review

A number of different conditions simultaneously affect both the lungs and the kidneys. These include autoimmune disorders and genetic tumor syndromes. Although manifestations within either organ system alone may not be specific, by observing the pattern of involvement and clinical history, radiologists may be able to suggest the correct diagnosis.

The lung in systemic vasculitis: radiological patterns and differential diagnosis

The respiratory system may be involved in all systemic vasculitides, although with a variable frequency. The aim of our review is to describe radiographic and high-resolution CT (HRCT) findings of pulmonary vasculitides and to correlate radiological findings with pathological results. Lung disease is a common feature of antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitides, including granulomatosis with polyangiitis (Wegener's), eosinophilic granulomatosis with polyangiitis (Churg-Strauss) and microscopic polyangiitis. Pulmonary involvement is less frequent in immune-complex-mediated small-vessel vasculitides, such as Behçet's disease and Goodpasture's syndrome. Pulmonary involvement associated to large-vessel (gigantocellular arteritis and Takayasu's disease) or medium-vessel (nodose polyarteritis and Kawasaki's disease) vasculitides is extremely rare. The present review describes the main clinical and radiological features of pulmonary vasculitides with major purpose to correlate HRCT findings (solitary or multiple nodules, cavitary lesions, micronodules with centrilobular or peribronchial distribution, airspace consolidations, "crazy paving", tracheobronchial involvement, interstitial disease) with pathological results paying particular attention to the description of acute life-threatening manifestations. A thorough medical history, careful clinical examination and the knowledge of radiological patterns are mandatory for a correct and early diagnosis.

Non-infectious Parenchymal Lung Disease

Acute dyspnea is a common presenting complaint in the emergency room, emergency medicine and intensive care. It may have a cardiovascular or a non-cardiovascular origin, the latter including pulmonary parenchymal diseases. Depending on the cause, it may be associated with fever, cough, hemoptysis, and/or chest pain, with a duration of symptoms that can range from hours to days.

Prompt identification of the underlying cause of acute dyspnea is essential in guiding appropriate therapy and management, as patients may rapidly progress to acute respiratory failure. Evaluation with chest radiography is vital for initial assessment and may reveal diffuse parenchymal abnormalities, which may require further assessment with computed tomography (HRCT).

Acute non-infectious parenchymal lung diseases are often overlooked and may be under-diagnosed. Their diagnosis requires the evaluation, along with the HRCT pattern, of the clinical and laboratory features and of the bronchoalveolar lavage. Biopsy may be necessary in more complex cases.

Although the most frequent cause of diffuse non-infectious parenchymal lung involvement is acute hydrostatic pulmonary edema, there is a wide variety of diseases that may be encountered, including acute drug toxicity, hypersensitivity pneumonitis (HP), acute respiratory distress syndrome (ARDS) and diffuse alveolar hemorrhage (DAH). In trauma patients, fat embolism syndrome (FES) must be taken into account. Acute respiratory failure is an eventuality that can occur during the course of chronic lung diseases (UIP for example), which may have been unknown until then.

Imaging of systemic vasculitis in childhood

The term "systemic vasculitis" encompasses a diverse set of diseases linked by the presence of blood-vessel inflammation that are often associated with critical complications. These diseases are uncommon in childhood and are frequently subjected to a delayed diagnosis. Although the diagnosis and treatment may be similar for adult and childhood systemic vasculitides, the prevalence and classification vary according to the age group under investigation. For example, Kawasaki disease affects children while it is rarely encountered in adults. In 2006, the European League Against Rheumatism (EULAR) and the Pediatric Rheumatology European Society (PReS) proposed a classification system for childhood vasculitis adopting the system devised in the Chapel Hill Consensus Conference in 1993, which categorizes vasculitides according to the predominant size of the involved blood vessels into small, medium and large vessel diseases. Currently, medical imaging has a pivotal role in the diagnosis of vasculitis given recent developments in the imaging of blood vessels. For example, early diagnosis of coronary artery aneurysms, a serious complication of Kawasaki disease, is now possible by magnetic resonance imaging (MRI) of the heart and multidetector computed tomography (MDCT); positron emission tomography/CT (PET/CT) helps to assess active vascular inflammation in Takayasu arteritis. Our review offers a unique approach using the integration of the proposed classification criteria for common systemic childhood vasculitides with their most frequent imaging findings, along with differential diagnoses and an algorithm for diagnosis based on common findings. It should help radiologists and clinicians reach an early diagnosis, therefore facilitating the ultimate goal of proper management of affected children.

Pulmonary vascular diseases

Pulmonary vascular diseases encompass a large and diverse group of underlying pathologies ranging from venous thromboembolism to congenital malformations to inflammatory vasculitides. As a result, patients can present either acutely with dyspnea and chest pain or chronically with dyspnea on exertion, hypoxia, and right heart failure. Imaging, particularly with multidetector CT, plays a key role in the evaluation and management of patients with suspected pulmonary vascular disease and, given the widespread routine use of high-quality CT pulmonary angiography, it is imperative that radiologists be familiar these pathologies.

Clear vision through the haze: a practical approach to ground-glass opacity

Ground-glass opacity (GGO) is a common, nonspecific imaging finding on chest computed tomography that may occur in a variety of pulmonary diseases. GGO may be the result of partial filling of alveolar spaces, thickening of the alveolar walls or septal interstitium, or a combination of partial filling of alveolar spaces and thickening of the alveolar walls and septal interstitium at the histopathologic level. Diseases that commonly manifest on chest computed tomography as GGO include pulmonary edema, alveolar hemorrhage, nonspecific interstitial pneumonia, hypersensitivity pneumonitis, and pulmonary alveolar proteinosis. Generating an extensive list of possible causes of GGO in radiologic reports would not be helpful to referring physicians. Preferably, a more concise and focused list of differential diagnostic possibilities may be constructed using a systematic approach to further classify GGO based on morphology, distribution, and ancillary imaging findings, such as the presence of cysts, traction bronchiectasis, and air trapping. Correlation with clinical history, such as the chronicity of symptoms, the patient's immune status, and preexisting medical conditions is vital. By thorough analysis of imaging patterns and consideration of relevant clinical information, the radiologist can generate a succinct and useful imaging differential diagnosis when confronted with the nonspecific finding of GGO.

Dyspnea due to pulmonary vessel arteritis

Pulmonary arteritis is a rare cause of pulmonary hypertension. Causes of pulmonary arteritis can be divided into primary and secondary, as well as classified according to vessel size. Only large vessel vasculitis is associated with pulmonary hypertension; primary forms include Takayasu arteritis and giant cell arteritis. The diagnosis of pulmonary arteritis can be challenging and the associated morbidity is serious without prompt, directed treatment. The authors present a case involving a 48-year-old First Nations man presenting with a six-month history of exertional dyspnea and severe stenosis of the left pulmonary artery, who was ultimately diagnosed with pulmonary arteritis related to large vessel vasculitis.

Giant cell arteritis of the thyroid in a 69-year-old male

We report the case of a 69-year-old Caucasian male with a histological confirmed diagnosis of giant cell arteritis (GCA) of the thyroid. To our knowledge this is the second reported case of GCA of the thyroid with a histological confirmed diagnosis. Unique to this case is that our patient did not have the simultaneous occurrence of a positive temporal artery biopsy or classic symptoms of temporal arteritis. The patient presented with fever of unknown origin, and fatigue. Laboratory reports included a sedimentation rate of >100 mm/h and C-reactive protein level of 17.1 mg/dL. Goiter with irregular calcifications was found on the computed tomography image. Temporal artery biopsy was negative. The patient continued to have intermittent fever after discharge and was readmitted to the hospital 41 days after discharge for fever and increasing fatigue. The thyroid was resected to rule out neoplasia. Granulomatous GCA was identified within the thyroid specimen.

Isolated large vessel pulmonary vasculitis as a cause of chronic obstruction of the pulmonary arteries

Isolated pulmonary artery involvement by large vessel vasculitis is rare. This case report describes two patients with large vessel pulmonary vasculitis initially thought to have chronic thromboembolic pulmonary hypertension who had their diagnosis revised following pulmonary endarterectomy surgery. Advances in imaging techniques such as positron emission tomography and magnetic resonance imaging have permitted complementary radiological methods of diagnosis and follow up of large vessel disease and these are discussed in conjunction with the immunosuppressive and operative management of these patients.

Mycophenolate mofetil as a maintenance therapy for lupus-related diffuse alveolar hemorrhage: a case report

Diffuse alveolar hemorrhage (DAH) is a life-threatening complication of systemic lupus erythematosus (SLE). Cases complicated with DAH often have active SLE with multi-organ involvement, especially lupus nephritis. We describe a rare case of DAH as the first presenting manifestation of SLE in the absence of lupus nephritis. Remission was induced by IV methylprednisolone, IV cyclophosphamide, and plasmapheresis. Further cycles of cyclophosphamide were prevented by recurrent infections. Maintenance of remission was successfully achieved with oral mycophenolate mofetil 1 g twice daily, with a good control of SLE and without further DAH episodes.

Imaging of pulmonary vasculitis

The presence of pulmonary vasculitis can be suggested by a clinical presentation that includes diffuse pulmonary hemorrhage, acute glomerulonephritis, chronic refractory sinusitis or rhinorrhea, imaging findings of nodules or cavities, mononeuritis multiplex, multisystemic disease, and palpable purpura. Serologic tests, including the use of cytoplasmic antineutrophil cytoplasmic antibody (ANCA) and perinuclear ANCA, are performed for the differential diagnosis of the diseases. A positive cytoplasmic ANCA test result is specific enough to make a diagnosis of ANCA-associated granulomatous vasculitis if the clinical features are typical. Perinuclear ANCA positivity raises the possibility of Churg-Strauss syndrome or microscopic polyangiitis. Imaging findings of pulmonary vasculitis are diverse and often poorly specific. The use of a pattern-based approach to the imaging findings may help narrow the differential diagnosis of various pulmonary vasculitides. Integration of clinical, laboratory, and imaging findings is mandatory for making a reasonably specific diagnosis.

Massive hemoptysis in an 11-year-old girl with isolated pulmonary arteritis

A 10-year-old girl developed recurrent bouts of massive hemoptysis over a 9-month period. No obvious bleeding source was detected. Her pulmonary angiogram showed a pulmonary aneurysm of the second branch of the left main pulmonary artery as well as widespread irregularities of the pulmonary arteries including areas of stenosis and pruning. Elective embolization of the aneurysm did not control hemoptysis and emergency left upper lobectomy had to be performed. Histology showed large artery wall injury with acute leucocytoclastic inflammation, fibrinoid necrosis, granulomatous inflammation, and ectasia of vessel wall. This combination of abnormalities has not been described to date and represents the first case of isolated pulmonary arteritis in children prior to puberty.