Aspiration diseases: findings, pitfalls, and differential diagnosis

Clinical and Imaging Features of Cystic Fibrosis in Korean Children

Cystic fibrosis (CF) is a fatal hereditary disorder that primarily affects Caucasians and is rare in Asian populations, including Koreans. Diagnosing CF is often challenging and delayed owing to its rarity and its overlapping features with non-CF diseases, ultimately affecting the patient prognosis. Radiologists can provide initial clues for clinically unsuspected cases and play a crucial role in establishing an early childhood diagnosis. This pictorial essay reviews the clinical and imaging features of genetically confirmed CF in Korean children and increases awareness of this rare disease, thereby facilitating early diagnosis.

Water soluble swallow for leak detection after total laryngectomy post radiotherapy

AIM

Pharyngeal leak (PL) and pharyngocutaneous fistula (PCF) are serious complications following total laryngectomy and their incidence is higher in the salvage setting. The aim of this study is to describe the accuracy of water soluble swallow (WSS) to rule out salivary postoperative leak after salvage total laryngectomy (STL) to expedite start of oral intake.

MATERIAL AND METHODS

Retrospective study including patients undergoing STL between 2008 and 2021 at Guy's Hospital. WSS was routinely performed within 15 days post operation.

RESULTS

Sixty-six patients underwent STL. Nine developed clinically diagnosed PCF; one died before having WSS. Fifty-six patients underwent WSS post STL. WSS was performed within 15 days after STL when no postoperative complications occurred (76.8%). Among patients undergoing WSS with no clinical suspicion for fistula (56), PL was identified in 15 cases (26.8%). They were managed conservatively; PCF was avoided in 7(46.7%) cases. Three patients (7.3%) developed PCF after having started oral intake with a negative WSS. These three cases were further analysed, 2 cases where recorded at the beginning of the studied period when less experience was available possibly leading to incorrect results. Sensitivity and negative predictive value (NPV) for fistula prediction were 72.7% and 92.7%, respectively.

CONCLUSION

Taking into account the high NPV of WSS, it is safe to start oral intake after negative WSS. Further studies to evaluate its accuracy earlier on after SLT are justified taking into account the results and the impact that delayed feeding has on patient's quality of life.

CT appearances of gastric injury due to caustic ingestion and associated findings (a study of 30 cases)

The mortality and morbidity of acute caustic gastric injuries are high. The spectrum of gastric injury due to caustic ingestion varies from hyperemia, erosion, and extensive ulcers to mucosal necrosis. Severe transmural necrosis can be associated with fistulous complications in the acute and subacute phases and stricture formation in the chronic phase. Due to these important clinical implications, timely diagnosis and appropriate management of gastric caustic injury are crucial, and endoscopy plays a pivotal role. However, critically ill patients or those with overt peritonitis and shock cannot undergo endoscopy. Thoraco-abdominal computed tomography (CT) is preferable to endoscopy as it avoids the risk of esophageal perforation and allows the evaluation of the entire gastrointestinal tract, as well as of the surrounding organs. With the advantage of not being invasive, CT scan has a promising role in the early evaluation of caustic injury. It has an increasing role in the emergency setting with good accuracy in identifying patients who are likely to benefit from surgery. In this pictorial essay, we present the CT spectrum of caustic injury of stomach and associated thoraco-abdominal injuries, with clinical follow-up.

Schematic approach to the diagnosis of multifocal lung opacities in the emergency department

Radiologists in the emergency department must be prepared to deal with any type of disease in any organ at any time. Many entities involving the chest can result in patients' presenting at the emergency department. This chapter deals with entities that manifest with multifocal lung opacities and that can be mistaken for pneumonia. To facilitate their identification, this chapter approaches these entities by considering their most characteristic distribution on chest X-rays, the main diagnostic modality used for thoracic problems in the emergency department. Our schematic approach includes the key findings in patients' personal histories, clinical examination, laboratory tests, and imaging studies that can be available during the initial workup.

Mycobacterium infection secondary to exogenous lipoid pneumonia caused by nasal drops: a case report and literature review

BACKGROUND

Exogenous lipoid pneumonia (ELP) is a rare disease and its diagnosis is often mistaken or delayed. Secondary infection with rapidly growing non-tuberculous mycobacteria is a rare complication of lipoid pneumonia.

CASE PRESENTATION

A 38-year-old man presented with fever, cough, sputum, chest tightness, and shortness of breath. He had a 2-year history of allergic rhinitis and used liquid paraffin-containing menthol nasal drops daily. A chest CT scan showed multiple patchy ground glass opacities with blurred borders in both lungs, which were located in the inner pulmonary field and distributed along the bronchi. His ambient air PO₂ was 63 mmHg. The patient was diagnosed with ELP by CT-guided lung biopsy. The nasal drops were discontinued, and systemic glucocorticoids were administered. During treatment, the pulmonary lesions deteriorated, and bronchoalveolar lavage was performed during bronchoscopy. Additionally, Mycobacterium abscessus was detected in the lavage fluid. Upon detection of a secondary M. abscessus infection, glucocorticoids were gradually discontinued, and anti-M. abscessus treatment was implemented. The patient's symptoms rapidly ameliorated. After 11 months of anti-M. abscessus treatment, a repeat CT scan showed clear regression of the lung lesions.

CONCLUSION

Routine microbiological examination of samples, including sputum or alveolar lavage fluid, is necessary for patients with diagnosed or suspected ELP.

How and when to manage respiratory infections out of hospital

Lower respiratory infections include acute bronchitis, influenza, community-acquired pneumonia, acute exacerbation of COPD and acute exacerbation of bronchiectasis. They are a major cause of death worldwide and often affect the most vulnerable: children, elderly and the impoverished. In this paper, we review the clinical presentation, diagnosis, severity assessment and treatment of adult outpatients with lower respiratory infections. The paper is divided into sections on specific lower respiratory infections, but we also dedicate a section to COVID-19 given the importance of the ongoing pandemic. Lower respiratory infections are heterogeneous entities, carry different risks for adverse events, and require different management strategies. For instance, while patients with acute bronchitis are rarely admitted to hospital and generally do not require antimicrobials, approximately 40% of patients seen for community-acquired pneumonia require admission. Clinicians caring for patients with lower respiratory infections face several challenges, including an increasing population of patients with immunosuppression, potential need for diagnostic tests that may not be readily available, antibiotic resistance and social aspects that place these patients at higher risk. Management principles for patients with lower respiratory infections include knowledge of local surveillance data, strategic use of diagnostic tests according to surveillance data, and judicious use of antimicrobials.

Imaging in the Intensive Care Unit

Radiology plays an important role in the management of the most seriously ill patients in the hospital. Over the years, continued advances in imaging technology have contributed to an improvement in patient care. However, even with such advances, the portable chest radiograph (CXR) remains one of the most commonly requested radiographic examinations. While they provide valuable information, CXRs remain relatively insensitive at revealing abnormalities and are often nonspecific. Chest computed tomography (CT) can display findings that are occult on CXR and is particularly useful at identifying and characterizing pleural effusions, detecting barotrauma including small pneumothoraces, distinguishing pneumonia from atelectasis, and revealing unsuspected or additional abnormalities which could result in increased morbidity and mortality if left untreated. CT pulmonary angiography is the modality of choice in the evaluation of pulmonary emboli which can complicate the hospital course of the ICU patient. This article will provide guidance for interpretation of CXR and thoracic CT images, discuss some of the invasive devices routinely used, and review the radiologic manifestations of common pathologic disease states encountered in ICU patients. In addition, imaging findings and complications of more specific clinical scenarios in which the incidence has increased in the ICU setting, such as patients who are immunocompromised, have interstitial lung disease, or COVID-19, will also be discussed. Communication between the radiologist and intensivist, particularly on complicated cases, is important to help increase diagnostic accuracy and leads to an improvement in the management of the most critically ill patients.

Interstitial Lung Abnormalities at CT: Subtypes, Clinical Significance, and Associations with Lung Cancer

Interstitial lung abnormality (ILA) is defined as an interstitial change detected incidentally on CT images. It is seen in 4%-9% of smokers and 2%-7% of nonsmokers. ILA has a tendency to progress with time and is associated with respiratory symptoms, decreased exercise capability, reduced pulmonary function, and increased mortality. ILAs can be classified into three subcategories: nonsubpleural, subpleural nonfibrotic, and subpleural fibrotic. In cases of ILA, clinically significant interstitial lung disease should be identified and requires clinically driven management by a pulmonologist. Risk factors for the progression of ILA include clinical elements (ie, inhalation exposures, medication use, radiation therapy, thoracic surgery, physiologic findings, and gas exchange findings) and radiologic elements (ie, basal and peripheral predominance and fibrotic findings). It is recommended that individuals with one or more clinical or radiologic risk factors for progression of ILA be actively monitored with pulmonary function testing and CT. To avoid overcalling ILA at CT, radiologists must recognize the imaging pitfalls, including centrilobular nodularity, dependent abnormality, suboptimal inspiration, osteophyte-related lesions, apical cap and pleuroparenchymal fibroelastosis-like lesions, aspiration, and infection. There is a close association between ILA and lung cancer, and many studies have reported an increased incidence of lung cancer, worse prognoses, and/or increased pulmonary complications in relation to cancer treatment in patients with ILA. ILA is considered to be an important comorbidity in patients with lung cancer. Accordingly, all radiologists involved with body CT must have sound knowledge of ILAs owing to the high prevalence and potential clinical significance of these anomalies. An overview of ILAs, including a literature review of the associations between ILAs and lung cancer, is presented. ©RSNA, 2022.

Physiology and pathophysiology of human airway mucus

The mucus clearance system is the dominant mechanical host defense system of the human lung. Mucus is cleared from the lung by cilia and airflow, including both two-phase gas-liquid pumping and cough-dependent mechanisms, and mucus transport rates are heavily dependent on mucus concentration. Importantly, mucus transport rates are accurately predicted by the gel-on-brush model of the mucociliary apparatus from the relative osmotic moduli of the mucus and periciliary-glycocalyceal (PCL-G) layers. The fluid available to hydrate mucus is generated by transepithelial fluid transport. Feedback interactions between mucus concentrations and cilia beating, via purinergic signaling, coordinate Na+ absorptive vs Cl- secretory rates to maintain mucus hydration in health. In disease, mucus becomes hyperconcentrated (dehydrated). Multiple mechanisms derange the ion transport pathways that normally hydrate mucus in muco-obstructive lung diseases, e.g., cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), non-CF bronchiectasis (NCFB), and primary ciliary dyskinesia (PCD). A key step in muco-obstructive disease pathogenesis is the osmotic compression of the mucus layer onto the airway surface with the formation of adherent mucus plaques and plugs, particularly in distal airways. Mucus plaques create locally hypoxic conditions and produce airflow obstruction, inflammation, infection, and, ultimately, airway wall damage. Therapies to clear adherent mucus with hydrating and mucolytic agents are rational, and strategies to develop these agents are reviewed.

CT imaging in idiopathic out-of-hospital cardiac arrest: An assessment of current practice and diagnostic utility

Idiopathic Out-Of-Hospital Cardiac Arrest (OHCA) requires urgent treatment. Early Computed Tomography (CT) imaging may be useful to aid diagnosis. We aimed to determine current CT imaging practice, safety, and diagnostic value in this patient population. This study was a single-centre, retrospective cohort study of patients presenting to the Emergency Department (ED) of the Royal Infirmary of Edinburgh with idiopathic non-traumatic OHCA and Return Of Spontaneous Circulation (ROSC). Between 1st January 2016 and 31st December 2019, 140 of 156 (90%) eligible patients underwent 195 CT scans identifying the cause of OHCA in 6 (4%). CT head diagnosed one ischaemic and three haemorrhagic strokes, and CT pulmonary angiogram diagnosed one acute coronary syndrome and one pulmonary embolism. CT head (134), CT pulmonary angiogram (25) and CT cervical spine (16) were the commonest scans. 68 of 195 (35%) CT scans showed important pathology, mostly secondary to OHCA. CT imaging was safe with no cases of contrast nephropathy, allergic reaction, or other complications. The diagnostic value of CT imaging in this patient population was limited. However, imaging was a valuable method of identifying other important secondary pathology.

Why is UIP peripheral?

INTRODUCTION

The radiology pattern associated with IPF is called UIP. It is unique because unlike any other form of fibrosis it is peripheral in its distribution. We investigated the peripheral nature of UIP and why it was a key feature of IPF the deadliest of the ILDS.

AREAS COVERED

It is not enough to say that UIP is peripheral but instead as scientists we must ask ourselves why it is peripheral. This review dives into the published hypothesis that includes vascular insult, tensile forces, microaspiration, and inflammation and looks at the pros and cons for each argument, and ultimately comes to its own conclusion. PubMed searches using the below keywords were used to identify papers that described pathogenesis of IPF with regard to a particular theory.

EXPERT OPINION

In this paper, we will review four ideas that support why UIP is peripheral and propose the most likely explanation given what is currently known about the pathophysiology of IPF.

A Clinical and Radiographic Paradox in a Case of Barium Aspiration

Barium studies are essential to the diagnostic work-up, especially in dysphagia, heartburn (dyspepsia), or gastroesophageal reflux (GERD). The barium swallow test, or esophagram, is essential in investigating patients with abnormalities within the esophagus. The barium sulfate used is inert to the gastrointestinal tract and causes no harm. However, problems begin when the contrast agent enters the trachea and then into the lungs. The author herein presents a case of barium aspiration in a 60 years old Indian male being investigated for the cause of dysphagia. In this case, the paradox was the radiograph's contradictory features and the patient's clinical features. The large aspiration on the radiograph alerted the clinicians. However, the patient was relatively asymptomatic, and thus a clinical and radiographic paradox should always be kept in the minds of the treating physicians, especially post barium aspiration.

Swallowing study using water-soluble contrast agents may increase aspiration sensitivity and antedate oral feeding without respiratory and drug complications: A STROBE-compliant prospective, observational, case-control trial

Although the modified barium swallowing study (MBSS) is considered the gold standard for assessing aspiration risk, aspiration of lipid-soluble barium can cause chemical pneumonitis or impair radiologic interpretation of the lungs. Water-soluble contrast agents (WSCAs) may avoid these complications while maintaining sensitivity on aspiration. This prospective, observational, case-control cohort trial evaluated all patients >3 years old referred for swallowing study from September 2015 to November 2017. Repeat evaluations of individuals were excluded. High-risk patients were evaluated by WSCA (iohexol)-based swallowing study (WSS) and others by MBSS. The study included 829 evaluations of 762 patients. After excluding 74 evaluations, 365 WSSs and 390 MBSSs were performed. The most frequent underlying condition was brain lesion, followed by aspiration pneumonia. Aspiration occurred more frequently in WSS (147 patients: 40.3%) than in MBSS (36 patients: 9.2%) (P = .00). However, neither aspiration volume (6.72 cc [3.09-10.35] vs 5.53 cc [2.21-8.85]) nor radiographic alterations differed between the 2 groups (P > .05). Moreover, the swallowed (16.62 cc [8.45-24.79]) and aspirated amounts of iohexol were not correlated with radiologic changes or deterioration (P > .05). Switching to oral feeding following WSS was more frequent (164 patients: 44.9%), whereas aspiration pneumonia was not (P = .00). WSS did not prolong the interval to patient discharge (P = .06) or induce an allergic reaction or chemotoxicity over 1 week. The absence of aspiration-induced complications and adverse drug effects suggests that, compared with MBSS, WSS may increase aspiration sensitivity and early switching to oral feeding.

Chemical Pneumonitis Caused by the Inhalation of Zinc Oxide Fumes in an Arc Welder

Acute respiratory illness caused by exposure to welding-associated zinc oxide fumes is known as metal fume fever (MFF). MFF is generally characterized as a self-limiting disease. Few studies have reported chemical pneumonitis associated with zinc fume inhalation. We report a case study involving severe episodes of MFF accompanied by chemical pneumonitis due to the inhalation of zinc oxide fumes while operating an arc welder. A 54-year-old man developed flu-like symptoms after arc welding galvanized steel in a poorly ventilated area. Despite intravenous antibiotics therapy, his clinical course worsened, and his urine zinc concentration was remarkably elevated (3579 μg/24 h; reference range, 0–616 μg/24 h). A chest computed tomography revealed extensive consolidation, ground-glass opacity in the lungs, and right pleural effusion. After corticosteroid treatment, the patient’s symptoms and radiologic findings significantly improved. It should be noted that the inhalation of zinc oxide fumes can occasionally induce acute lung injury via inflammatory responses and oxidative stress.

Hydrocarbon pneumonitis with abscess formation following diesel siphoning

A man in his early 40s presented with a 1-month history of fever after accidental diesel aspiration. He had received treatment with intravenous antibiotics, steroids and supportive care. Contrast-enhanced CT of the thorax revealed a right middle lobe lung abscess and bronchoscopy revealed hyperaemia around the middle lobe bronchus. The abscess was initially managed by drainage using a pigtail catheter and intravenous antibiotics. However, only partial drainage of the abscess was achieved and fever persisted. The cardiothoracic surgery team performed drainage of lung abscess through a right posterolateral thoracotomy. Postprocedure, the patient's symptoms improved and the patient was discharged in good health. This case demonstrates a rare complication of hydrocarbon aspiration pneumonitis and lung abscess. Post acute management of diesel aspiration, patients should be advised to return for medical assessment immediately, should symptoms like persistent fever and chest pain recur or persist as these symptoms may herald the development of post-hydrocarbon-aspiration lung abscess.

Factors associated with gravity-dependent distribution on chest CT in elderly patients with community-acquired pneumonia: a retrospective observational study

Although lung involvement in aspiration pneumonia typically has a gravity-dependent distribution on chest images, which patient’s conditions contribute to its radiological pattern has not been fully elucidated. This study was designed to determine the factors associated with the gravity-dependent distribution of community-acquired pneumonia (CAP) on chest computed tomography (CT). This retrospective study included elderly patients aged ≥ 65 years with CAP who underwent chest CT within 1 week before or after admission. The factors associated with lower lobe- and posterior-predominant distributions of ground glass opacity or airspace consolidation were determined. Of the 369 patients with CAP, 348 (94%) underwent chest CT. Multivariate analyses showed that impaired consciousness, a low Barthel index of activities of daily living, and high hemoglobin levels were associated with lower lobe-predominant distribution, while male sex and impaired consciousness were associated with posterior-predominant distribution. Cerebrovascular diseases were unrelated to these distributions. While male sex, impaired consciousness, high hemoglobin levels, low albumin levels, and the number of involved lobes were associated with in-hospital mortality, gravity-dependent distributions were not. Impaired consciousness might be the most significant predictor of aspiration pneumonia; however, the gravity-dependent distribution of this disease is unlikely to affect disease prognosis.

COVID-19 and Aspiration Pneumonia: Similar Pulmonary Findings with Different Diagnoses—a Pitfall in [18F]FDG PET/CT

Since December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a worldwide pandemic. Especially in the centers most affected by the pandemic, symptoms (such as fever, cough, myalgia, or fatigue) and/or radiological signs (such as ground-glass opacity) typically related to COVID-19 often diverted clinicians’ attention from other diseases. Despite the urgency to recognize and cure SARS-CoV-2 infection, a plethora of differential diagnoses must be considered, and other diseases must be equally and promptly treated, as described in this case report.

Non-Infectious Granulomatous Lung Disease: Imaging Findings with Pathologic Correlation

Non-infectious granulomatous lung disease represents a diverse group of disorders characterized by pulmonary opacities associated with granulomatous inflammation, a relatively nonspecific finding commonly encountered by pathologists. Some lesions may present a diagnostic challenge because of nonspecific imaging features; however, recognition of the various imaging manifestations of these disorders in conjunction with patients' clinical history, such as age, symptom onset and duration, immune status, and presence of asthma or cutaneous lesions, is imperative for narrowing the differential diagnosis and determining appropriate management of this rare group of disorders. In this pictorial review, we describe the pathologic findings of various non-infectious granulomatous lung diseases as well as the radiologic features and high-resolution computed tomography imaging features.

Ground-glass opacity (GGO): a review of the differential diagnosis in the era of COVID-19

Thoracic imaging is fundamental in the diagnostic route of Coronavirus disease 2019 (COVID-19) especially in patients admitted to hospitals. In particular, chest computed tomography (CT) has a key role in identifying the typical features of the infection. Ground-glass opacities (GGO) are one of the main CT findings, but their presence is not specific for this viral pneumonia. In fact, GGO is a radiological sign of different pathologies with both acute and subacute/chronic clinical manifestations. In the evaluation of a subject with focal or diffuse GGO, the radiologist has to know the patient’s medical history to obtain a valid diagnostic hypothesis. The authors describe the various CT appearance of GGO, related to the onset of symptoms, focusing also on the ancillary signs that can help radiologist to obtain a correct and prompt diagnosis.

When pneumonia is not COVID-19

During the COVID-19 epidemic, the prevalence of the disease means that practically any lung opacity on an X-ray could represent pneumonia due to infection with SARS-CoV-2. Nevertheless, atypical radiologic findings add weight to negative microbiological or serological tests. Likewise, outside the epidemic wave and with the return of other respiratory diseases, radiologists can play an important role in decision making about diagnoses, treatment, or preventive measures (isolation), provided they know the key findings for entities that can simulate COVID-19 pneumonia. Unifocal opacities or opacities located in upper lung fields and predominant airway involvement, in addition to other key radiologic and clinical findings detailed in this paper, make it necessary to widen the spectrum of possible diagnoses.

When pneumonia is not COVID-19

During the COVID-19 epidemic, the prevalence of the disease means that practically any lung opacity on an X-ray could represent pneumonia due to infection with SARS-CoV-2. Nevertheless, atypical radiologic findings add weight to negative microbiological or serological tests. Likewise, outside the epidemic wave and with the return of other respiratory diseases, radiologists can play an important role in decision making about diagnoses, treatment, or preventive measures (isolation), provided they know the key findings for entities that can simulate COVID-19 pneumonia. Unifocal opacities or opacities located in upper lung fields and predominant airway involvement, in addition to other key radiologic and clinical findings detailed in this paper, make it necessary to widen the spectrum of possible diagnoses.

Diesel siphoner's lung: An unusual cause of hydrocarbon pneumonitis

The practice of manual siphoning of diesel from fuel tanks is common among automobile mechanics in Nepal. When an automobile mechanic with a history of diesel siphonage presents with respiratory symptoms, the diesel siphoner's lung diagnosis should be considered. Clinical suspicion confirmed by radiological findings can help in early management and prevention of permanent damage.

Investigation of high-resolution computed tomographic (HRCT) outcomes associated with chronic pulmonary microaspiration (CPM) in Tehran and Zahedan, Iran

Background

In patients with chronic pulmonary microaspiration (CPM) the recognition of high-resolution computed tomographic (HRCT) findings and their pattern is important.

Objective

To investigate the HRCT detections in patients with CPM.

Materials and Methods

This descriptive study enrolled 100 consecutive patients with CPM underwent HRCT of the lungs between 2017 and 2018 in Tehran and Zahedan Hospitals and private centers. The required variables were recorded for each patient with a questionnaire. Subsequently, HRCT was performed and abnormalities were then reported by two radiologists.

Results

Most of patients exhibited bronchial thickening in 33.6% of cases, followed by ground-glass opacity (12.4%), emphysema (11.1%), and bronchiectasis (8.5%). In addition, the most common HRCT findings were found in left lower lobe (LLL) (37.1%), followed by right lower lobe (RLL) (35.9 %), right upper lobe (RUL) (6,2%), and left upper lobe (LUL) (6%).

Conclusion

Our data showed the most common findings in HRCT were bronchial thickening ground-glass opacity, emphysema, and bronchiectasis, where these findings was dominantly found in LLL, RLL, RUL, and LUL, indicating its high tendency to dependent areas.

Review of the Chest CT Differential Diagnosis of Ground-Glass Opacities in the COVID Era

Coronavirus disease 2019 (COVID-19), a recently emerged lower respiratory tract illness, has quickly become a pandemic. The purpose of this review is to discuss and differentiate typical imaging findings of COVID-19 from those of other diseases, which can appear similar in the first instance. The typical CT findings of COVID-19 are bilateral and peripheral predominant ground-glass opacities. As per the Fleischner Society consensus statement, CT is appropriate in certain scenarios, including for patients who are at risk for and/or develop clinical worsening. The probability that CT findings represent COVID-19, however, depends largely on the pretest probability of infection, which is in turn defined by community prevalence of infection. When the community prevalence of COVID-19 is low, a large gap exists between positive predictive values of chest CT versus those of reverse transcriptase polymerase chain reaction. This implies that with use of chest CT there are a large number of false-positive results. Imaging differentiation is important for management and isolation purposes and for appropriate disposition of patients with false-positive CT findings. Herein the authors discuss differential pathology with close imaging resemblance to typical CT imaging features of COVID-19 and highlight CT features that may help differentiate COVID-19 from other conditions.

COVID-19 pneumonia: the great radiological mimicker

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread worldwide since December 2019. Although the reference diagnostic test is a real-time reverse transcription-polymerase chain reaction (RT-PCR), chest-computed tomography (CT) has been frequently used in diagnosis because of the low sensitivity rates of RT-PCR. CT findings of COVID-19 are well described in the literature and include predominantly peripheral, bilateral ground-glass opacities (GGOs), combination of GGOs with consolidations, and/or septal thickening creating a "crazy-paving" pattern. Longitudinal changes of typical CT findings and less reported findings (air bronchograms, CT halo sign, and reverse halo sign) may mimic a wide range of lung pathologies radiologically. Moreover, accompanying and underlying lung abnormalities may interfere with the CT findings of COVID-19 pneumonia. The diseases that COVID-19 pneumonia may mimic can be broadly classified as infectious or non-infectious diseases (pulmonary edema, hemorrhage, neoplasms, organizing pneumonia, pulmonary alveolar proteinosis, sarcoidosis, pulmonary infarction, interstitial lung diseases, and aspiration pneumonia). We summarize the imaging findings of COVID-19 and the aforementioned lung pathologies that COVID-19 pneumonia may mimic. We also discuss the features that may aid in the differential diagnosis, as the disease continues to spread and will be one of our main differential diagnoses some time more.

Multimodality imaging of COVID-19 pneumonia: from diagnosis to follow-up. A comprehensive review

Due to its pandemic diffusion, SARS- CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection represents a global threat. Despite a multiorgan involvement has been described, pneumonia is the most common manifestation of COVID-19 (Coronavirus disease 2019) and it is associated with a high morbidity and a considerable mortality. Especially in the areas with high disease burden, chest imaging plays a crucial role to speed up the diagnostic process and to aid the patient management. The purpose of this comprehensive review is to understand the diagnostic capabilities and limitations of chest X-ray (CXR) and high-resolution computed tomography (HRCT) in defining the common imaging features of COVID-19 pneumonia and correlating them with the underlying pathogenic mechanisms. The evolution of lung abnormalities over time, the uncommon findings, the possible complications, and the main differential diagnosis occurring in the pandemic phase of SARS-CoV-2 infection are also discussed.

Journey of the Nasal Septum Into the Lungs: A Unique Complication of Cocaine Abuse

Cocaine is a powerful addictive stimulant drug which is known to have a wide range of adverse effects across the spectrum of organ systems. Pulmonary complications have been widely reported. Intranasal inhalation has its own sequelae of complications. It is also quite common that patients who use cocaine also use other drugs. Polysubstance abuse may result in varying detrimental effects. Here, we report a unique case of nasal septal aspiration as a complication of intranasal cocaine inhalation with concomitant alcohol abuse. It is hypothesized the patient perforated his nasal septum due to chronic intranasal inhalation of cocaine and he subsequently aspirated his septum as a result of central nervous system depression secondary to alcohol intoxication.

Noninfectious Granulomatous Diseases of the Chest

Granulomas are pathologically defined as focal aggregations of activated macrophages, Langerhans cells, and lymphocytes. Granulomas form in the lungs when the immune system barricades the substances it perceives as foreign but is unable to remove. Granulomas manifest with numerous imaging appearances in thoracic radiology, and their presence is a nonspecific finding. Granulomatous lung diseases comprise multiple entities with variable clinical manifestations and outcomes. Their imaging findings are rarely specific and can mimic malignancies, often triggering an extensive diagnostic workup. Radiologists must be familiar with the clinical manifestations and imaging findings of these entities to generate appropriate differential diagnoses. This review describes the imaging manifestations of various noninfectious, necrotizing, and nonnecrotizing granulomatous diseases that primarily affect the thorax. ©RSNA, 2020.

Exogenous lipoid pneumonia: when radiologist makes the difference

PURPOSE

To report high-resolution CT (HRCT) findings in our group of patients with exogenous lipoid pneumonia (ELP), confirmed with histopathological findings and clinical-anamnestic data, in order to describe the most common radiological patterns of this rare disorder.

MATERIALS AND METHODS

In this retrospective study, HRCT of 10 patients with ELP were evaluated by three radiologists. Diagnosis of ELP was made through CT, bronchiolo-alveolar lavage (BAL) and a pneumological examination associated with an accurate medical anamnesis. Five patients had a histologically proven ELP, through lung biopsy. All patients had a chronic exposition to substances made of animal fat or mineral/vegetable oils.

RESULTS

In our cohort of patients with ELP, the following parenchymal patterns were observed: 8/10 patients had lung consolidation with adipose density (attenuation values < - 40 HU); 10/10 patients had multiple areas of ground glass opacity; 6/10 patients had smooth thickening of interlobular septa and ground glass opacities ("crazy-paving" pattern); 2/10 patients presented nodules > 2.5 cm with spiculated margins (tumor-like); 5/10 patients showed reactive lymph nodes enlargement. The oldest lesions were characterized by bronchiectasis and fibrosis around the lipidic consolidations.

CONCLUSION

Pulmonary alterations found in HRCT exams can be confused with other lung diseases (especially lung tumors) and they are always a challenge even for the most experienced radiologist. In our experience, although non-specific, consolidation areas with low HU values and crazy-paving pattern are frequently associated in ELP. These characteristics should alert the radiologist to consider ELP among the possible differential diagnoses, always correlating the results of CT examination with appropriate clinical-laboratory evaluations and an accurate anamnesis.

Spectrum of 18F-FDG Uptake in Bilateral Lung Parenchymal Diseases on PET/CT

Bilateral lung parenchymal involvement is seen in infective as well as noninfective conditions, appearing as focal or diffuse lung disease. PET/CT with FDG helps in characterization (increased glucose utilization is seen by both inflammatory and neoplastic cells). In this article, we describe the spectrum of patterns of FDG uptake and associated CT changes involving bilateral lung parenchyma. Benign conditions described are aspiration pneumonia; pulmonary toxicity by bleomycin; infections, namely, sarcoidosis, miliary pulmonary tuberculosis, and pulmonary nocardiosis; and inflammatory conditions such as pulmonary Langerhans cell histiocytosis and pulmonary alveolar proteinosis. Neoplastic conditions described are bilateral pulmonary metastases and lymphangitic carcinomatosis.

Fatal Aspiration of Barium Sulfate in a Case of Myasthenia Gravis: A Case Report and Review of Literature

Barium contrast radiography is a usual procedure performed for detecting lesions of the digestive tract using barium sulfate on X-ray irradiation. The aspiration of barium contrast is an uncommon but well-documented complication occurring accidentally during examinations of the upper gastrointestinal system using contrast media. Certain conditions that affect the anatomical and functional integrity of the oropharynx and esophagus can be predisposing factors. Barium is an inert material that can cause symptoms varying from an asymptomatic mechanical obstruction to severe respiratory distress that can result in death when aspirated. Sudden death due to aspiration of barium is rarely reported in the literature. We report a case of a 50-year-old female who suddenly developed difficulty in breathing, followed by loss of consciousness during barium swallow procedure due to aspiration of barium contrast. She could not be revived and died within a few minutes of the episode. The predisposing factor was the weakness of the muscles of deglutition due to myasthenia gravis. We also reviewed the literature available on cases resulting from the aspiration of barium sulfate during the barium study procedures. We considered the factors like the age, indications, the distribution of barium in the lungs, clinical presentation, the period of survival, and cause of death. We came across only four cases of death within 24 h following the aspiration of barium. This case report and review of literature emphasize the importance of consideration of predisposing factors before conducting barium contrast radiography and also the possibility of sudden death.

The Diagnosis of Exogenous Lipoid Pneumonia Caused by the Silent Aspiration of Vegetable Oil Using a Lipidomic Analysis

We herein report a case of refractory exogenous lipoid pneumonia that was successfully attributed to vegetable oil through a lipidomic analysis of bronchoalveolar lavage fluid (BALF). As a 25-year-old woman diagnosed with lipoid pneumonia experienced repeated exacerbations and improvement, we performed a BALF lipidomic analysis. The major lipid components were oleic acid, linoleic acid, and α-linolenic acid, which are constituents of vegetable oil. She stopped consuming any vegetable oil and has since experienced no instances of lipoid pneumonia relapse. A lipidomic analysis appears to be useful for identifying causative lipids, since patients with lipoid pneumonia are sometimes unaware of aspiration episodes.

Barium sulfate aspiration: Is early bronchioalveolar lavage a life-saving procedure?

Aspiration of barium sulfate is a well-known complication, occurring accidentally during contrast-enhanced examinations of the upper gastrointestinal system. Massive aspiration of contrast material causes mechanical obstruction that increases alveolar dead space leading to altered ventilation/perfusion (V/Q) ratio with secondary respiratory failure and death. The potential treatment strategies include early recognition of predisposing factors, pretreatment with antireflux medications, such as domperidone, correct choice of contrast media, and use of retroesophageal suction catheter during barium swallow study. We report a case of barium swallow aspiration, which was successfully managed by early institution of bronchioalveolar lavage (BAL) and positive pressure mechanical ventilation. Till date, BAL has not been recommended for the same, with studies showing it can worsen the clinical scenario.

Chest radiography in adult critical care unit: A pictorial review

Patients in the intensive care units suffer from a myriad of cardiopulmonary processes for which portable chest radiography is the most utilized imaging modality. A pragmatic approach toward evaluating the nearly similar radiographic findings seen in most of the pathologies with comparative review and strong clinical acumen can help the radiologists and clinicians achieve a rapid and precise diagnosis.

Educational Case: Aspiration Pneumonia

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Immediate Prone Positioning After Massive Gastric Aspiration Reduces Lung Injury Possibly by Attenuating Interleukin-6-Mediated Lung-Tissue Inflammation in Pigs

Gastric aspiration, which can cause acute, diffuse, inflammatory lung injury, is of particular concern in critically ill patients. This study aimed to determine the effects of immediate prone positioning on the degree of lung injury and inflammatory response induced by gastric aspiration. Following induction of gastric aspiration by injection of gastric fluid, 16 healthy pigs were randomized to one of two groups: supine position (SP) or prone position (PP). After ventilation and monitoring for 6 hr, all pigs were euthanized. The ratio of the partial pressure of arterial oxygen/fraction of inspired oxygen (P_aO2/F_IO2) and the partial pressure of arterial carbon dioxide (P_aCO2) were recorded during the 6-hr study period. Serum levels of interleukin (IL)-6 were measured every 2 hr, and the mean optical density (MOD) of IL-6 in lung tissues and lung-injury scores were measured at the end of the experiment. The PP group showed a significantly higher P_aO2/F_IO2 ratio, lower serum IL-6 concentration (p = .015), lower lung-injury scores (p = .012), and lower IL-6 concentration and MOD of IL-6 in lung tissue, especially in dorsal (p = .001, p = .021, respectively) and nondependent regions (p = .005, p = .035, respectively) than the SP group. There were no statistically significant differences in P_aCO2 between the groups. Lung-injury severity was positively correlated with the IL-6 concentration and MOD of IL-6 in lung tissues (p < .05). These results suggest that immediate prone positioning alleviated the degree of aspiration-induced lung injury, possibly through mitigating IL-6-mediated lung inflammation.

Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest

PURPOSE

Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting.

METHODS

This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region.

RESULTS

Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care.

CONCLUSIONS

An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.

Brazilian consensus on non-cystic fibrosis bronchiectasis

Bronchiectasis is a condition that has been increasingly diagnosed by chest HRCT. In the literature, bronchiectasis is divided into bronchiectasis secondary to cystic fibrosis and bronchiectasis not associated with cystic fibrosis, which is termed non-cystic fibrosis bronchiectasis. Many causes can lead to the development of bronchiectasis, and patients usually have chronic airway symptoms, recurrent infections, and CT abnormalities consistent with the condition. The first international guideline on the diagnosis and treatment of non-cystic fibrosis bronchiectasis was published in 2010. In Brazil, this is the first review document aimed at systematizing the knowledge that has been accumulated on the subject to date. Because there is insufficient evidence on which to base recommendations for various treatment topics, here the decision was made to prepare an expert consensus document. The Brazilian Thoracic Association Committee on Respiratory Infections summoned 10 pulmonologists with expertise in bronchiectasis in Brazil to conduct a critical assessment of the available scientific evidence and international guidelines, as well as to identify aspects that are relevant to the understanding of the heterogeneity of bronchiectasis and to its diagnostic and therapeutic management. Five broad topics were established (pathophysiology, diagnosis, monitoring of stable patients, treatment of stable patients, and management of exacerbations). After this subdivision, the topics were distributed among the authors, who conducted a nonsystematic review of the literature, giving priority to major publications in the specific areas, including original articles, review articles, and systematic reviews. The authors reviewed and commented on all topics, producing a single final document that was approved by consensus.

Pneumonia in a Teenager Hiding a Fire-Eating Stunt

Pneumonia in children due to hydrocarbon aspiration is usually the result of an uncommon accidental event. However, an acute and severe type of pneumonia induced by hydrocarbon aspiration is occasionally experienced by entertainers known as fire-eaters. Different approaches to treat fire-eater's pneumonia appear in the literature. Although there is no consensus regarding the management of this condition, the use of antibiotic therapy is well recognized and recommended by some, whereas others recommend only supportive treatment. Steroids are indicated in severe cases.Here, we report the case of a boy who developed severe pneumonia after inhaling hydrocarbons during an attempt to mimic a fire-eater show. Slow resolution was achieved after broad-spectrum antibiotic therapy in addition to systemic and inhaled steroids and physiotherapy.

Prophylactic pre-esophagogastroduodenoscopy tracheal intubation in patients with upper gastrointestinal bleeding

The indications for endotracheal intubation (ETI) during an esophagogastroduodenoscopy (EGD) procedure remain unclear. This study performed a descriptive analysis of patients who underwent prophylactic tracheal intubation during or before an EGD to prevent pulmonary aspiration. We selected patients with an upper gastrointestinal bleed in an intensive care unit who underwent EGD between 2000 and 2013. Eighty-nine patients who underwent pre-EGD tracheal intubation were analyzed. The main outcomes in this study were pulmonary aspiration, length of stay, and mortality. The average age of patients undergoing pre-EGD intubation was 61 years. The incidence of pulmonary aspiration was 38% in patients who underwent pre-EGD tracheal intubation. The patients requiring tracheal intubation had a mortality rate of 22% during hospitalization. Other complications in pre-EGD ETI patients included myocardial infarction (9%), acute respiratory distress syndrome (10%), and pulmonary edema (7%). In conclusion, the incidence of pulmonary aspiration with pre-EGD tracheal intubation in our patients was high (38%). Cardiopulmonary complications including myocardial infarction, acute respiratory distress syndrome, and pulmonary edema were high in intubated patients.

Foreign Body Aspiration: An Unusual Presentation and Outcome

Foreign body aspiration mostly presents as acute emergency with cough, choking and dyspnoea. Rarely aspiration of foreign body may be the underlying cause in patients presenting with long term symptomatologies. Here is a case of 60-year-old male who came for surgical management of cholelithiasis. During his workup, X-ray chest revealed right paracardiac opacity. Fibre-optic bronchoscopy showed a mass lesion in right main bronchus. It was taken out of the airways by flexible bronchoscope but could not be retrieved. Subsequent chest radiographs showed marked improvement.

The role of imaging in the diagnosis of bronchiectasis: the key is in the distribution

Diseases that involve the medium caliber airways (segmental and subsegmental bronchi) are common and present clinically with nonspecific respiratory symptoms such as cough, recurrent respiratory infections and occasionally, hemoptysis. The abnormal and irreversible dilation of bronchi is known as "bronchiectasis". The diagnosis can be challenging and the analysis of the regional distribution of the bronchiectasis is the most useful diagnostic guide. The objective of this manuscript is to describe the main imaging findings of bronchiectasis and their classification, review the diseases that most commonly present with this abnormality, and provide an approach to the diagnosis based on their imaging appearance and anatomic distribution. Bronchiectasis is a frequent finding that may result from a broad range of disorders. Imaging plays a paramount role in diagnosis, both in the detection and classification, and in the diagnosis of the underlying pathology.