10), hemothorax, and sequelae of previous talc pleurodesis, lobectomy, or pneumonectomy. 7). Example of feeding vessel sign. They may become indirectly visible on CT images when filled with mucus, pus, fluid, or cells, forming impactions that resemble a budding tree with branching nodular V- and Y-shaped opacities that are referred to as the tree-in-bud sign [6–9] (Fig. 19). The diagnostic accuracy of various roentgenographic signs of pneumonia has not been assessed previously in the portable anteroposterior roentgenograms obtained in ventilated patients. Wheezing has also been noted 59,90. An abnormal chest roentgenogram is essential for the diagnosis of ventilator-associated pneumonia. The miliary pattern consists of multiple small (< 3 mm) pulmonary nodules of similar size that are randomly distributed throughout both lungs [2]. The halo sign is the CT finding of a peripheral rim of ground-glass opacity surrounding a pulmonary nodule or mass [2, 32]. The hydatid cyst is composed of three layers: an outer protective barrier consisting of modified host cells, called the pericyst; a middle acellular laminated membrane, called the ectocyst; and an inner germinal layer that produces scolices, hydatid fluid, daughter vesicles, and daughter cysts, called the endocyst [74, 75, 77]. These signs are suggestive of invasive fungal infection (e.g., angioinvasive Aspergillus infection or mucormycosis) in susceptible patient populations [66]. 16 —63-year-old man with squamous cell lung cancer. Das SK et al. Also present are foci of air (arrowheads) representing early abscess formation and small loculated right pleural effusion (asterisks). In: StatPearls [Internet]. Example of water lily sign. 9). The air crescent sign is suggestive of a favorable patient prognosis [41]. It is important to consider a diagnosis of bacterial pneumonia in a patient with fever and cough when the silhouette sign is detected at chest radiography. The intracavitary nodule represents necrotic, retracted lung tissue that is separated from peripheral viable but hemorrhagic lung parenchyma seen as outer consolidation or ground-glass opacity [42]. Incidence is higher at the extremes of age. Bronchoscopy may be necessary to exclude endobronchial tumor as the cause of the finger-in-glove sign. From the case: COVID-19 pneumonia. There is often associated pleural effusion, omental fat stranding, and anterior cardiophrenic and internal mammary lymphadenopathy. Noninfectious causes of the miliary pattern include metastatic disease, IV injected foreign material, and rarely sarcoidosis [62, 63]. The air sacs may fill with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing. Other diseases that can manifest the silhouette sign include atelectasis (segmental or lobar), aspiration, pleural effusion, and tumor [ … 17). The crazy-paving sign was originally described as a characteristic CT pattern detected in patients with pulmonary alveolar proteinosis. Radiologic Signs on an award-winning, radiologic teaching site for medical students and those starting out in radiology focusing on chest, GI, cardiac and musculoskeletal diseases containing over 200 PowerPoint lectures, quizzes, hand-out notes, interactive material, most commons lists and pictorial differential diagnoses Differential diagnostic considerations include nonobstructive atelectasis, aspiration, and neoplasms, such as adenocarcinoma and lymphoma. The crazy-paving sign is the CT finding of a combination of ground-glass opacity and smooth interlobular septal thickening that resembles a masonry pattern used in walkways [2]. CT scanning of the chest is one of the most important imaging modalities available to a pulmonologist. In a patient with pneumonia, detection of an air-fluid level on chest radiographs or CT images suggests the presence of a lung abscess or empyema with bronchopleural fistula. 7 —55-year-old man with necrotizing aspiration pneumonia. Example of finger-in-glove sign. Axial CT image shows multiple bilateral pulmonary nodules with surrounding ground-glass opacity. Clinical features of Legionella include diarrhea, headache, myalgias, dyspnea and cough. Fig. In very severe cases, COVID-19 pneumonia can lead to acute respiratory distress syndrome (ARDS), a … When the imaging manifestations of a known disease entity form a consistent pattern or characteristic appearance, those manifestations may be regarded as an imaging sign of that disease. Axial CT image shows diffuse ground-glass opacity with areas of superimposed interlobular septal thickening (combination that forms crazy-paving pattern) and multiple thin-walled cysts. Copyright © 2013-2020, American Roentgen Ray Society, ARRS, All Rights Reserved. Paragonimus westermani and Paragonimus kellicotti are the two pathogens endemic to Asia and North America, respectively. Coronal CT image shows septic pulmonary emboli manifesting themselves as peripheral solid and cavitary pulmonary nodules of varying sizes. Seven roentgenographic signs (air bronchograms, alveolar infiltrates, silhouette sign, cavities, fissure abutment, atelectasis, and … Fig. 2). Example of split-pleura sign. Fig. Adjacent atelectasis is evident in right lower lobe. 16), bronchial atresia, cystic fibrosis, and postinflammatory bronchiectasis [45–47]. The air crescent sign is not specific for Aspergillus infection and can be seen in other conditions, such as cavitating neoplasm, intracavitary clot, and Wegener granulomatosis [2, 43, 44]. Fig. 19 —55-year-old man with chronic coccidioidomycosis infection. After reading the article and taking the test, the reader will be able to 1. The second form of the immature organism lives in the crab or crayfish. 20). The feeding vessel sign is the CT finding of a pulmonary vessel coursing to a distal pulmonary nodule or mass. Recognizing the linear burrow track is the key to differentiating this entity from others, such as malignancy, fungal infection, and tuberculosis [80–83]. 15), probably because of the presence of calcium salts, metals, and desiccated mucus [47–50]. A variety of organisms, including bacteria, viruses and fungi, can cause pneumonia.Pneumonia can range in seriousness from mild to life-threatening. Fig. 10 —65-year-old man with malignant pleural effusion. The radiological findings of CMV infection are variable consisting of lobar consolidation, diffuse and focal parenchymal haziness, and multiple small nodules with associated areas of ground-glass attenuation (“halo”) (fig. Detection of an air-fluid level at chest radiography should prompt evaluation of its location as being in the lung parenchyma or within the pleural space. Lung abscess is most commonly associated with aspiration pneumonia and septic pulmonary emboli. Axial supine (left) and prone (right) CT images show gravity dependence of fungal ball (mycetoma). Though the sign is most commonly seen with bacterial infection, any infection can manifest the air bronchogram sign. Some radiologists believe that the meniscus sign is suggestive of impending cyst rupture [76, 77]. Chest CT images show air between pericyst and ectocyst layers (arrows) consistent with meniscus sign. Humans can serve as intermediate hosts after contact with a definitive host (e.g., dog or wolf) or after consuming contaminated vegetables or water [74]. The purposes of this article are to describe common and uncommon imaging signs and patterns of pulmonary infections and to discuss their underlying anatomic and pathophysiologic basis. Fig. The disease may be sporadic, though outbreaks have occurred from colonization of air conditioning towers, water distribution systems and humidifiers. Proximal portion of branching opacity was FDG avid (not shown) and represented tumor, whereas rest of opacity represented mucoid impaction in dilated bronchus. Air Bronchogram Sign Branching, linear, tubular lucency representing a bronchus or bronchiole passing through airless lung parenchyma. Over time the lesion may deflate, or it may rupture into the pleural space, the result being pneumothorax [56, 59]. 23). Fig. In patients with chronic symptoms, crazy-paving sign may represent lipoid pneumonia, lung cancer, or pulmonary alveolar proteinosis (PAP). Differential diagnostic considerations are influenced by patient's clinical presentation and disease course. Clinical signs of radiologic pneumonia in . (Courtesy of Rossi S, Centro de Diagnostico Dr Enrique Rossi, Buenos Aires, Argentina). 3 —45-year-old man with reactivation tuberculosis. The burrow sign is a linear track extending from the pleural surface or hemidiaphragm to a cavitary or cystic pulmonary nodule. 22). Accreditation and Designation Statement The RSNA is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical educati… Example of finger-in-glove sign. c Consolidations were the dominant CT nding on day 14 The feeding vessel sign was initially considered diagnostic of septic emboli (Fig. 2. Fig. This study was performed at a university-affiliated tertiary hospital in the Republic of Korea, between January 1, 2015, and July 31, 2020. Imaging features that favor mucormycosis over Aspergillus infection in a neutropenic patient are detection of the reverse halo or bird's nest sign, multiplicity of pulmonary nodules (> 10), and development of infection despite voriconazole prophylaxis [66–68]. No mediastinal lymphadenopathy. 11 —35-year-old man with fever, neutropenia, and angioinvasive Aspergillus infection. Intracavitary nodule (asterisks) represents necrotic lung tissue. Example of inhomogeneous enhancement. Silhouette signs: Loss of clarity of the diaphragm and heart borders 4. This pattern implies hematogenous dissemination of disease and is classically associated with tuberculosis but can also be seen with other infections, such as histoplasmosis and coccidioidomycosis, particularly in immunocompromised individuals [60] (Fig. Pulmonary hydatid disease is a zoonotic parasitic infection caused by the larval stage of Echinococcus tapeworms [74]. 17 —24-year-old man with HIV infection and Pneumocystis pneumonia. Of note, some of the interstitial lung diseases are termed pneumonia rather than pneumonitis. (Courtesy of Loomis S, REMS Media Services, Mass General Imaging, Boston, MA), Fig. [8] Uterine Leiomyosarcoma: Can MRI Differentiate Leiomyosarcoma From Benign Leiomyoma Before Treatment? No pleural effusion. 15A —25-year-old woman with allergic bronchopulmonary aspergillosis (ABPA). Diagnostic tests including radiologic studies and blood or serologic tests that could help establish the cause of pneumonia would reduce the use of antibiotics and may improve the clinical course. Differential considerations for randomly distributed pulmonary nodules include miliary infection (e.g., tuberculosis, histoplasmosis), metastatic disease, and rarely sarcoidosis. CONCLUSION. Eur. Prompt detection at imaging studies may improve patient care, enabling clinicians to treat patients with an appropriate course of antibiotic therapy [27]. Keywords: abscess, fungus, infection, signs. 21). • Describe the most common viral infections in immunocompetent and in immunocompromised patients. Consolidation is an alveolar-filling process that replaces air within the affected airspaces, increasing in pulmonary attenuation and obscuring the margins of adjacent airways and vessels on radiographs and CT scans [2]. Or mucormycosis ) in susceptible patient populations [ 66 ] axial supine ( left ) Cumbo., metastatic disease, and water lily signs are suggestive of angioinvasive Aspergillus infection abscess. Paragonimiasis after ingestion of raw crayfish sub-pleural consolidations suggest viral pneumonias [ 101,102 ] Leiomyosarcoma from Benign before..., linear subpleural consolidation in left upper lobe consolidation due to Aspergillus species with AIDS ( count... In whom pneumonia was suspected, overall clinical opinion of the chest has to. 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Increase the likelihood of VAP with pneumococcal pneumonia [ 18 ] usually requires insertion of a area!