Reversed halo sign: high-resolution CT scan findings in 79 patients

Ultrasonic humidifier lung with a reversed halo sign: A case report

The reversed halo sign was initially reported as a representative computed tomography scan finding of cryptogenic organizing pneumonia. Since then, however, it has been reported in various diseases and is now considered a nonspecific finding. However, there are no cases of humidifier lung with the reversed halo sign. An 82-year-old Japanese male patient presented with moving difficulties 48 days after starting darolutamide treatment for prostate cancer. He was admitted to the hospital due to acute pneumonia, which presented as bilateral extensive nonsegmental ground-glass opacities in the peripheral regions and extensive areas of ground-glass opacity with a circumferential halo of consolidation, with the reversed halo sign on computed tomography scan. After darolutamide discontinuation with the concomitant administration of antibiotics, the patient's pneumonia improved, and he was discharged from the hospital. However, within a few days, he was again admitted to the hospital due to pneumonia. He was found to have been using an ultrasonic humidifier at home and was then diagnosed with humidifier lung based on the bronchoscopy and provocative testing findings. Hence, ultrasonic humidifier lung should be considered as a differential diagnosis in patients presenting with the reversed halo sign, and a detailed medical history must be taken.

Diffuse reversed halo sign in an immunocompetent patient

The reversed halo sign (RHS) is a specific radiological image observed mostly on computed tomography (CT) scans as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation. It is common to many entities of respiratory diseases and can be found in both infectious, noninfectious inflammatory pathologies and some malignant tumors, including invasive pulmonary fungal infection, tuberculosis (TB), community-acquired pneumonia, granulomatosis, sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation and radiofrequency. We report the case of an immunocompetent 54-year-old North African male patient, initially hospitalized for chronic cough associated with dysphonia and general symptoms such as weight loss, fever, and night sweats. Radiological exploration surprisingly confirmed the presence of RHS, tuberculosis was confirmed by a postbronchoscopy positive sputum Xpert MTB/RIF essay tuberculosis after we started antibacillary treatment, and the evolution was spectacular with regression of the lesions. The objective of this report is to increase knowledge about RHS and its pathological correlation with TB. Since it is not specific to any disorder, it is important to explore its finding in a clinical and epidemiological manner, especially in endemic countries where the prevalence of tuberculosis is still high.

Radiological Diagnosis of Pulmonary Aspergillosis

Imaging plays an important role in the various forms of Aspergillus-related pulmonary disease. Depending on the immune status of the patient, three forms are described with distinct imaging characteristics: invasive aspergillosis affecting severely immunocompromised patients, chronic pulmonary aspergillosis affecting less severely immunocompromised patients but suffering from a pre-existing structural lung disease, and allergic bronchopulmonary aspergillosis related to respiratory exposure to Aspergillus species in patients with asthma and cystic fibrosis. Computed tomography (CT) has been demonstrated more sensitive and specific than chest radiographs and its use has largely contributed to the diagnosis, follow-up, and evaluation of treatment in each condition. In the last few decades, CT has also been described in the specific context of cystic fibrosis. In this particular clinical setting, magnetic resonance imaging and the recent developments in artificial intelligence have shown promising results.

Imaging of Pulmonary Sarcoidosis-A Review

Sarcoidosis is the classic multisystem granulomatous disease. First reported as a disorder of the skin, it is now clear that, in the overwhelming majority of patients with sarcoidosis, the lungs will bear the brunt of the disease. This review explores some of the key concepts in the imaging of pulmonary sarcoidosis: the wide array of typical (and some of the less common) findings on high-resolution computed tomography (HRCT) are reviewed and, with this, the concept of morphologic/HRCT phenotypes is discussed. The pathophysiologic insights provided by HRCT through studies where morphologic abnormalities and pulmonary function tests are compared are evaluated. Finally, this review outlines the important contribution of HRCT to disease monitoring and prognostication.

Pulmonary reversed halo cycles and consolidations after immunotherapy: A case report

BACKGROUND

Immune checkpoint inhibitor-associated interstitial lung disease (ICI-ILD) and opportunistic pneumonias are the main pulmonary complications during immunotherapy for malignancies. The organizing pneumonia (OP) pattern is one of the common radiological manifestations of ICI-ILD, and OP is the most common cause of reversed halo cycles and consolidations. However, opportunistic pneumonias should be excluded.

CASE SUMMARY

In this report, we described a case of a 44-year-old man with esophageal cancer who showed multiple reversed-halo cycles and consolidations on chest computed tomography (CT) after he had a cold during immunotherapy. He was diagnosed with esophageal squamous-cell cancer (T2NIM0) after surgery. Then, he was successfully treated with 6 cycles of chemotherapy plus tislelizumab, one cycle of radiotherapy and 9 cycles of tislelizumab. Two months later, he complained of low-grade fever and cough with nonpurulent sputum after he had a cold. Community-acquired pneumonia was considered, but moxifloxacin was ineffective. Chest CT showed multiple reversed-halo cycles and consolidations. Mycobacterium tuberculosis was identified with next-generation sequence analysis of bronchoalveolar lavage fluid (BALF). Two months later, he improved with standard anti-tuberculosis medications. Both the cycles and consolidations disappeared in the repeat CT after 6 mo of medications.

CONCLUSION

When chest CT shows reversed-halo cycles and consolidations in patients during anticancer immunotherapy, both ICI-ILD and infectious pneumonia should be considered. BALF microbiological analysis was helpful to differentiate them.

Imaging of Invasive Fungal Infections- The Role of PET/CT

Over the last decades, the population at risk for invasive fungal disease (IFD) has increased because of medical therapy advances and diseases compromising patients' immune systems. The high morbidity and mortality associated with invasive fungal disease in the immunocompromised present the challenge of early diagnosis of the IFD and the need to closely monitor the infection during treatment. The definitive diagnosis of invasive fungal disease based on culture or histopathological methods often has reduced diagnostic accuracy in the immunocompromised and may be very invasive. Less invasive and indirect evidence of the fungal infection by serology and imaging has been used for the early diagnosis of fungal infection before definitive results are available or when the definitive methods of diagnosis are suboptimal. Imaging in invasive fungal disease is a non-invasive biomarker that helps in the early diagnosis of invasive fungal disease but helps follow-up the infection during treatment. Different imaging modalities are used in the workup to evaluate fungal disease. The different imaging modalities have advantages and disadvantages at different sites in the body and may complement each other in the management of IFD. Positron emission tomography integrated with computed tomography with [18F]Fluorodeoxyglucose (FDG PET/CT) has helped manage IFD. The combined functional data from PET and anatomical data from the CT from almost the whole body allows noninvasive evaluation of IFD and provides a semiquantitative means of assessing therapy. FDG PET/CT adds value to anatomic-based only imaging modalities. The nonspecificity of FDG uptake has led to the evaluation of other tracers in the assessment of IFD. However, these are mainly still at the preclinical level and are yet to be translated to humans. FDG PET/CT remains the most widely evaluated radionuclide-based imaging modality in IFD management. The limitations of FDG PET/CT must be well understood, and more extensive prospective studies in uniform populations are needed to validate its role in the management of IFD that can be international guidelines.

Consensus guidelines for the diagnosis and management of invasive fungal disease due to moulds other than Aspergillus in the haematology/oncology setting, 2021

Invasive fungal disease (IFD) due to moulds other than Aspergillus is a significant cause of mortality in patients with malignancies or post haemopoietic stem cell transplantation. The current guidelines focus on the diagnosis and management of the common non-Aspergillus moulds (NAM), such as Mucorales, Scedosporium species (spp.), Lomentospora prolificans and Fusarium spp. Rare but emerging NAM including Paecilomyces variotii, Purpureocillium lilacinum and Scopulariopsis spp. are also reviewed. Culture and histological examination of tissue biopsy specimens remain the mainstay of diagnosis, but molecular methods are increasingly being used. As NAM frequently disseminate, blood cultures and skin examination with biopsy of any suspicious lesions are critically important. Treatment requires a multidisciplinary approach with surgical debridement as a central component. Other management strategies include control of the underlying disease/predisposing factors, augmentation of the host response and the reduction of immunosuppression. Carefully selected antifungal therapy, guided by susceptibility testing, is critical to cure. We also outline novel antifungal agents still in clinical trial which offer substantial potential for improved outcomes in the future. Paediatric recommendations follow those of adults. Ongoing epidemiological research, improvement in diagnostics and the development of new antifungal agents will continue to improve the poor outcomes that have been traditionally associated with IFD due to NAM.

Challenges in the diagnosis of pulmonary mucormycosis in a diabetic with a review of literature

Diabetes Mellitus appears to be the most common underlying condition associated with mucormycosis; a rare opportunistic fungal infection associated with high morbidity and mortality. Pulmonary mucormycosis may mimic pneumonia and thus pose challenges in achieving a timely diagnosis critical to successful outcomes. We present a case of a 65-year-old diabetic who presented with fever and haemoptysis that was managed as pneumonia. A bronchial alveolar lavage grew Rhizopus mould that was thought to be a contaminant as he responded well to antibiotics. He required another admission in 4 weeks due to worsening symptoms. Failure to respond to antibiotics and ongoing clinical and radiological deterioration led to a lobectomy that confirmed a diagnosis of pulmonary mucormycosis. He responded well to surgical resection and antifungal therapy with a complete recovery. Elusive clinical presentation and insensitive conventional diagnostic techniques may make the diagnosis of mucormycosis challenging. Our case reports highlight the issues involved in the diagnosis and management of pulmonary Mucormycosis mimicking as pneumonia.

COVID-19 imaging: Diagnostic approaches, challenges, and evolving advances

The role of radiology and the radiologist have evolved throughout the coronavirus disease-2019 (COVID-19) pandemic. Early on, chest computed tomography was used for screening and diagnosis of COVID-19; however, it is now indicated for high-risk patients, those with severe disease, or in areas where polymerase chain reaction testing is sparsely available. Chest radiography is now utilized mainly for monitoring disease progression in hospitalized patients showing signs of worsening clinical status. Additionally, many challenges at the operational level have been overcome within the field of radiology throughout the COVID-19 pandemic. The use of teleradiology and virtual care clinics greatly enhanced our ability to socially distance and both are likely to remain important mediums for diagnostic imaging delivery and patient care. Opportunities to better utilize of imaging for detection of extrapulmonary manifestations and complications of COVID-19 disease will continue to arise as a more detailed understanding of the pathophysiology of the virus continues to be uncovered and identification of predisposing risk factors for complication development continue to be better understood. Furthermore, unidentified advancements in areas such as standardized imaging reporting, point-of-care ultrasound, and artificial intelligence offer exciting discovery pathways that will inevitably lead to improved care for patients with COVID-19.

Heerfordt's Syndrome Associated with Trigeminal Nerve Palsy and Reversed Halo Sign

Heerfordt's syndrome is a rare subtype of sarcoidosis and features a combination of facial palsy, parotid swelling, and uveitis, associated with a low-grade fever. Cases with two of three symptoms are called "incomplete Heerfordt's syndrome." Heerfordt's syndrome involving other cranial nerve symptoms is relatively rare. We herein report a case of incomplete Heerfordt's syndrome presenting with trigeminal nerve palsy and a reversed halo sign, a rare manifestation of pulmonary sarcoidosis. The histological diagnosis following a biopsy of the parotid gland and endobronchial ultrasound-guided trans-bronchial needle aspiration of the mediastinal lymph nodes was sarcoidosis. The symptoms and lung lesions improved after corticosteroid therapy.

Guidance on Imaging for Invasive Pulmonary Aspergillosis and Mucormycosis: From the Imaging Working Group for the Revision and Update of the Consensus Definitions of Fungal Disease from the EORTC/MSGERC

BACKGROUND

Clinical imaging in suspected invasive fungal disease (IFD) has a significant role in early detection of disease and helps direct further testing and treatment. Revised definitions of IFD from the EORTC/MSGERC were recently published and provide clarity on the role of imaging for the definition of IFD. Here, we provide evidence to support these revised diagnostic guidelines.

METHODS

We reviewed data on imaging modalities and techniques used to characterize IFDs.

RESULTS

Volumetric high-resolution computed tomography (CT) is the method of choice for lung imaging. Although no CT radiologic pattern is pathognomonic of IFD, the halo sign, in the appropriate clinical setting, is highly suggestive of invasive pulmonary aspergillosis (IPA) and associated with specific stages of the disease. The ACS is not specific for IFD and occurs in the later stages of infection. By contrast, the reversed halo sign and the hypodense sign are typical of pulmonary mucormycosis but occur less frequently. In noncancer populations, both invasive pulmonary aspergillosis and mucormycosis are associated with "atypical" nonnodular presentations, including consolidation and ground-glass opacities.

CONCLUSIONS

A uniform definition of IFD could improve the quality of clinical studies and aid in differentiating IFD from other pathology in clinical practice. Radiologic assessment of the lung is an important component of the diagnostic work-up and management of IFD. Periodic review of imaging studies that characterize findings in patients with IFD will inform future diagnostic guidelines.

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.

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.

Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium

BACKGROUND

Invasive fungal diseases (IFDs) remain important causes of morbidity and mortality. The consensus definitions of the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group have been of immense value to researchers who conduct clinical trials of antifungals, assess diagnostic tests, and undertake epidemiologic studies. However, their utility has not extended beyond patients with cancer or recipients of stem cell or solid organ transplants. With newer diagnostic techniques available, it was clear that an update of these definitions was essential.

METHODS

To achieve this, 10 working groups looked closely at imaging, laboratory diagnosis, and special populations at risk of IFD. A final version of the manuscript was agreed upon after the groups' findings were presented at a scientific symposium and after a 3-month period for public comment. There were several rounds of discussion before a final version of the manuscript was approved.

RESULTS

There is no change in the classifications of "proven," "probable," and "possible" IFD, although the definition of "probable" has been expanded and the scope of the category "possible" has been diminished. The category of proven IFD can apply to any patient, regardless of whether the patient is immunocompromised. The probable and possible categories are proposed for immunocompromised patients only, except for endemic mycoses.

CONCLUSIONS

These updated definitions of IFDs should prove applicable in clinical, diagnostic, and epidemiologic research of a broader range of patients at high-risk.

Lung involvement in ANCA-associated vasculitis

Lung involvement is one of the most common clinical features in ANCA-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). In this review, we detail the five main presentations of pulmonary involvement in AAV: necrotizing granulomatous inflammation, tracheobronchial inflammation, pulmonary capillaritis, interstitial lung disease (ILD) and asthma with their clinical, radiological and therapeutic characteristics. The prevalence of these manifestations is variable according to the subtype of AAV, necrotizing granulomatous inflammation and tracheobronchial inflammation being defining features of GPA whereas ILD is primarily seen in patients with MPA, especially in association with ANCA directed against myeloperoxydase (MPO-ANCA), and asthma is characteristic of EGPA. Despite recent progresses in the diagnosis and management of these conditions, several questions remain and are discussed here, including local treatments for subglottic stenosis, the uncertain efficacy of plasma exchanges for alveolar hemorrhage, the potential role of antifibrotic agents in ILD associated with MPA, and the use of novel anti-IL-5 strategies in EGPA.

The Reversed Halo Sign: Not Such a Specific Sign of Organising Pneumonia

The reversed halo sign is defined as a focal rounded area of ground-glass opacity surrounded by a more or less complete ring of consolidation. It is a relatively rare sign and initially considered a specific sign of organising pneumonia. We report the case of a 55-year-old female who was being followed-up in a pulmonology consultation due to a 6 mm nodule which required vigilance. On a re-evaluation chest CT scan, besides a stable 6 mm nodule, a 36 mm mass with the reversed halo sign was diagnosed. The presence of the reversed halo sign misled the multidisciplinary team into the diagnosis of organising pneumonia and initiation of corticotherapy was suggested. However, after further investigation, a final diagnosis of pulmonary tuberculosis was made. Even though this sign is relatively rare, and still considered an important clue to the diagnosis of organising pneumonia in immunocompetent patients, other causes must be excluded before starting treatment.

Approach to Peribronchovascular Disease on CT

Diseases that are predominantly peribronchovascular in distribution on computed tomography by definition involve the bronchi, adjacent vasculature, and associated lymphatics involving the central or axial lung interstitium. An understanding of diseases that can present with focal peribronchovascular findings is useful for establishing diagnoses and guiding patient management. This review will cover clinical and imaging features that may assist in differentiating amongst the various causes of primarily peribronchovascular disease.

Significance of the Reverse Halo Sign in Immunocompromised Patients

OBJECTIVE. The purpose of this study is to assess the most common causes of the reverse halo sign (RHS) in immunocompromised patients and to identify clinicoradiologic features that help in achieving a specific diagnosis. MATERIALS AND METHODS. This retrospective study included 70 patients with hematologic malignancy, neutropenia, or history of solid organ transplant or stem cell transplant who had the RHS at chest CT. Absolute neutrophil count, imaging features of the RHS, and presence of pleural effusions were noted and correlated with the specific diagnosis. A decision tree was constructed from predictive imaging features and compared with radiologist assessment for infectious versus noninfectious cause. RESULTS. Infection, including fungal and bacterial pneumonia, was the most common cause of the RHS (66%), followed by organizing pneumonia (26%). Noninfectious causes such as organizing pneumonia were more likely in the solid organ transplant group, whereas infections were more likely in patients with hematologic malignancy and stem cell transplant. Among fungal pneumonias, aspergillosis (20%) was as common as mucormycosis (19%). In univariate analysis, neutropenia, rim thickness, central ground-glass attenuation, and lesion diameter correlated with infectious cause. A decision tree using neutropenia, rim thickness, central ground-glass attenuation, and pleural effusion could differentiate infectious from noninfectious cause with accuracy of 78%, compared with radiologist accuracy of 81%. CONCLUSION. Infections are more likely to cause RHS than noninfectious processes in immunocompromised patients, and aspergillosis may be as likely overall as mucormycosis because of its higher frequency in these patients. A decision tree using clinical and imaging features can help differentiate infectious from noninfectious causes of RHS.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Tomographic assessment of thoracic fungal diseases: a pattern and signs approach

Pulmonary fungal infections, which can be opportunistic or endemic, lead to considerable morbidity and mortality. Such infections have multiple clinical presentations and imaging patterns, overlapping with those of various other diseases, complicating the diagnostic approach. Given the immensity of Brazil, knowledge of the epidemiological context of pulmonary fungal infections in the various regions of the country is paramount when considering their differential diagnoses. In addition, defining the patient immunological status will facilitate the identification of opportunistic infections, such as those occurring in patients with AIDS or febrile neutropenia. Histoplasmosis, coccidioidomycosis, and paracoccidioidomycosis usually affect immunocompetent patients, whereas aspergillosis, candidiasis, cryptococcosis, and pneumocystosis tend to affect those who are immunocompromised. Ground-glass opacities, nodules, consolidations, a miliary pattern, cavitary lesions, the halo sign/reversed halo sign, and bronchiectasis are typical imaging patterns in the lungs and will be described individually, as will less common lesions such as pleural effusion, mediastinal lesions, pleural effusion, and chest wall involvement. Interpreting such tomographic patterns/signs on computed tomography scans together with the patient immunological status and epidemiological context can facilitate the differential diagnosis by narrowing the options.

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

"Pulmonary Vein Sign" for Pulmonary Embolism Diagnosis in Computed Tomography Angiography

PURPOSES

Considering that pulmonary arterial obstruction decreases venous flow, we hypothesized that filling defects in pulmonary veins can be identified in areas adjacent to pulmonary embolism (PE). This sign was named the "pulmonary vein sign" (PVS), and we evaluated its prevalence and performance for PE diagnosis in computed tomography pulmonary angiography (CTPA).

METHODS

This retrospective study enrolled consecutive patients with clinical suspicion of PE who underwent CTPA scan. The PVS was defined by the following criteria: (a) presence of a homogeneous filling defect of at least 2 cm in a pulmonary vein; (b) attenuation of the left atrium > 160 Hounsfield units. Using the cases that presented PE on CTPA as reference, sensitivity, specificity, and positive and negative predictive values were calculated for PVS.

RESULTS

In total, 119 patients (73 female; mean age, 62 years) were included in this study. PE was diagnosed in 44 (35.8%) patients. The PVS was present in 16 out of 44 patients with PE. Sensitivity was 36.36% (95% confidence interval (CI) 22.83-52.26%); specificity, 98.67% (95% CI 91.79-99.93%); positive predictive value, 94.12% (95% CI 69.24-99.69%); negative predictive value, 72.55% (95% CI 62.67-80.70%). The Kappa index for the PVS was good (0.801; 95% CI 0.645-0.957). PVS was correlated with lobar and segmental pulmonary embolism (p < 0.01).

CONCLUSION

Despite a low sensitivity, presence of the pulmonary vein sign was highly specific for PE, with a good agreement between readers. This sign could contribute for PE diagnosis on CTPA studies.

Drivers and impact of antifungal therapy in critically ill patients with Aspergillus-positive respiratory tract cultures

Invasive pulmonary aspergillosis (IPA) is an increasingly recognised problem in critically ill patients. Little is known about how intensivists react to an Aspergillus-positive respiratory sample or the efficacy of antifungal therapy (AFT). This study aimed to identify drivers of AFT prescription and diagnostic workup in patients with Aspergillus isolation in respiratory specimens as well as the impact of AFT in these patients. ICU patients with an Aspergillus-positive respiratory sample from the database of a previous observational, multicentre study were analysed. Cases were classified as proven/putative IPA or Aspergillus colonisation. Demographic, microbiological, diagnostic and therapeutic data were collected. Outcome was recorded 12 weeks after Aspergillus isolation. Patients with putative/proven IPA were more likely to receive AFT than colonised patients (78.7% vs. 25.5%; P <0.001). Patients with host factors for invasive fungal disease were more likely to receive AFT (72.5% vs. 37.4%) as were those with multiorgan failure (SOFA score >7) (68.4% vs. 36.9%) (both P <0.001). Once adjusted for disease severity, initiation of AFT did not alter the odds of survival (HR = 1.40, 95% CI 0.89-2.21). Likewise, treatment within 48 h following diagnosis did not change the clinical outcome (75.7% vs. 61.4%; P = 0.63). Treatment decisions appear to be based on diagnostic criteria and underlying disease severity at the time of Aspergillus isolation. IPA in this population has a dire prognosis and AFT is not associated with reduced mortality. This may be explained by delayed diagnosis and an often inevitable death due to advanced multiorgan failure.

Pulmonary mucormycosis: clinical features and outcomes

PURPOSE

Mucormycosis encompasses a group of opportunistic fungal infections caused by Zygomycetes, order Mucorales. Mucormycosis can manifest as rhino-orbito-cerebral, pulmonary, gastrointestinal, cutaneous, and disseminated infections. Pulmonary mucormycosis is the second most common presentation. This manuscript characterizes the demographics, clinical presentation, diagnostic procedures, radiologic findings, therapeutic interventions, and outcome in pulmonary mucormycosis.

METHODS

We retrospectively reviewed clinical data of 35 patients with pulmonary mucormycosis from 2000 to 2015. Microbiologic diagnosis was based on positive culture from a sterile site or findings on histopathology consistent with mucormycosis. Independent predictors of 28-day mortality were assessed using logistic regression. Survival curves were estimated using Kaplan-Meier method.

RESULTS

There was male predominance with a mean age of 55 ± 15 years. Analysis of predisposing conditions revealed the prevailing presence of malignancy. Sixty-six percent of patients were receiving immunosuppressive agents. Common presenting clinical findings were fever, neutropenia, dyspnea, and cough. Radiologic findings included pleural effusion and nodules. All patients received medical therapy and 43% underwent additional surgical intervention. Twenty eight day mortality was 29% with concurrent bacteremia found as the sole independent predictor. Similar survival from pulmonary mucormycosis was noted over time.

CONCLUSIONS

Pulmonary mucormycosis is an opportunistic angioinvasive fungal infection. Physicians must have a high level of suspicion in immunocompromised patients with fever and respiratory symptoms refractory to antibiotics. A low threshold should be had for performing an invasive procedure to gain reliable diagnosis, as early, aggressive medical and surgical interventions are needed for successful treatment.

Intravascular Large B Cell Lymphoma as a Rare Cause of Reversed Halo Sign: A Case Report

Intravascular large B cell lymphoma (IVLBCL) is a rare type of extranodal diffused large B-cell lymphoma. IVLBCL with primary lung lesion is very rare and it is very difficult to diagnose. Radiographic findings of pulmonary IVLBCL are nonspecific and resembling interstitial lung diseases. Reversed halo sign (RHS) was initially reported in patients diagnosed with cryptogenic organizing pneumonia and then described in a variety of diseases with inflammatory, infectious, autoimmune, and malignant causes. This is the first case of IVLBCL that has presented with RHSs on CT scan.A 59-year-old Chinese man presented with a 4-month history of a nonproductive cough and a weight loss of 5 kg. Physical examination was unremarkable. High-resolution computed tomography scan of the chest showed bilateral patchy ground glass opacities (GGOs) and RHSs. Laboratory tests were unremarkable except elevated serum lactate dehydrogenase (LDH). Surgical lung biopsy was performed. Light microscopic examination of the specimen disclosed diffuse alveolar septal widening caused by neoplastic lymphocytes, which were positive for CD20 and infiltrated in the alveolar capillaries. The patient was diagnosed with IVLBCL and underwent chemotherapy and autologous blood stem cell transplantation. The patient is still alive 5 years after diagnosis.IVLBCL is a rare cause of RHS and should be considered in differential diagnosis of RHS. An increased serum LDH concentration is another important clue.

Pediatric vasculitis: recognizing multisystemic manifestations at body imaging

Pediatric vasculitides are multisystem diseases that can be diagnostic challenges because of variable clinical manifestations. The clinical manifestation is determined by the size of the affected vessels, organs involved, extent of vascular injury, and underlying pathologic characteristics. Henoch-Schönlein purpura and Kawasaki disease are the two most common subtypes of pediatric vasculitis. Diagnosis of pediatric vasculitis can be difficult, and the outcome can be serious or fatal in the absence of timely intervention. Imaging plays a central role in establishing the diagnosis of vasculitis involving large- and medium-sized vessels, visualizing its vascular and extravascular manifestations, and monitoring the disease course and response to treatment. Although imaging cannot depict the vessel changes of small-vessel vasculitis directly, it can be used to detect tissue damage resulting from vessel inflammation. This article discusses the classification and clinical features of the major pediatric vasculitides. The imaging approach to and nonneurologic findings of major pediatric vasculitis subtypes are reviewed for the pediatric body imager.

[Cryptogenic organizing pneumonia]

INTRODUCTION

Organizing pneumonia is a particular type of inflammatory reaction of the lung which gives rise to a clinico-pathological syndrome. It is called "secondary" when a cause such as an infection, a drug toxicity, or a connective tissue disease can be identified, or "cryptogenic" when no cause is identified. The clinical picture is usually characterized by the subacute onset of fever, fatigue, cough and dyspnea, with multiple subpleural areas of consolidation on thoracic imaging.

STATE OF THE ART

Organizing pneumonia is characterised by the presence of buds of endoalveolar connective tissue. These result from an injury to the alveolar epithelium, followed by the deposition of fibrin in the alveolar spaces, and the migration of fibroblasts which produce a myxoid endoalveolar matrix. A remarkable feature of organizing pneumonia is the complete disappearance of these endoalveolar buds with corticosteroid treatment, in sharp contrast with what is seen in pulmonary fibrosis. The clinical response to corticosteroids is usually prompt and excellent. Relapses are frequent but usually benign.

PERSPECTIVES AND CONCLUSION

As the clinical, imaging and pathological characteristics of organizing pneumonia are now well established, many questions remain unanswered, such as the mechanisms involved in the complete reversibility of the pulmonary lesions, and the role of steroid-sparing treatments such as immunomodulatory macrolides.

Organizing pneumonia: chest HRCT findings

OBJECTIVE:

To determine the frequency of HRCT findings and their distribution in the lung parenchyma of patients with organizing pneumonia.

METHODS:

This was a retrospective review of the HRCT scans of 36 adult patients (26 females and 10 males) with biopsy-proven organizing pneumonia. The patients were between 19 and 82 years of age (mean age, 56.2 years). The HRCT images were evaluated by two independent observers, discordant interpretations being resolved by consensus.

RESULTS:

The most common HRCT finding was that of ground-glass opacities, which were seen in 88.9% of the cases. The second most common finding was consolidation (in 83.3% of cases), followed by peribronchovascular opacities (in 52.8%), reticulation (in 38.9%), bronchiectasis (in 33.3%), interstitial nodules (in 27.8%), interlobular septal thickening (in 27.8%), perilobular pattern (in 22.2%), the reversed halo sign (in 16.7%), airspace nodules (in 11.1%), and the halo sign (in 8.3%). The lesions were predominantly bilateral, the middle and lower lung fields being the areas most commonly affected.

CONCLUSIONS:

Ground-glass opacities and consolidation were the most common findings, with a predominantly random distribution, although they were more common in the middle and lower thirds of the lungs.

CT morphological features of the reversed halo sign in pulmonary paracoccidioidomycosis

OBJECTIVE

The purpose of this study was to identify morphological characteristics of the reversed halo sign (RHS) on chest CT in patients with pulmonary paracoccidioidomycosis (PCM) that may aid the diagnosis of this fungal disease.

METHODS

We retrospectively reviewed chest CT images from 23 patients with proven pulmonary PCM who demonstrated the RHS. Two chest radiologists analysed the morphological characteristics of the lesions and reached decisions by consensus.

RESULTS

We identified 64 RHSs on CT images from the 23 patients. Multiple lesions were observed in all cases, with middle and lower lung zone predominance occurring in 17 patients (73.9% of cases). 34 (53.1%) RHSs were round and 30 (46.9%) were oval. Outer borders of the RHSs were smooth in 32 (50%) lesions, nodular in 16 (25%) lesions and irregular/spiculated in 16 (25%) lesions. Ground-glass opacity was observed inside 63 (98.4%) lesions.

CONCLUSION

Our data suggest that morphological characteristics of the RHS on chest CT, such as the presence of multiple lesions, middle and lower lung zone predominance and a spiculated RHS ring, as well as the association with other parenchymal patterns, should lead radiologists to include PCM in the differential diagnosis of PCM in endemic areas.

ADVANCES IN KNOWLEDGE

This is the largest series of patients with RHS due to PCM and is also the first study to report RHS lesions with spiculated or irregular walls. The study adds information regarding morphological characteristics of the RHS that may raise suspicion of PCM on chest CT, particularly in endemic areas of the disease.

Mucormycosis: a new concern in the transplant ward?

PURPOSE OF REVIEW

This study focuses on the epidemiology and management of mucormycosis in hematopoietic stem cell transplant patients, a life-threatening mold infection whose incidence has increased over the past decades.

RECENT FINDINGS

Mucormycosis may occur in hematopoietic stem cell transplant recipients with severe graft-versus-host disease, steroids, neutropenia, iron overload, diabetes, and malnutrition, or those who received antifungals not active against Mucorales. Its incidence in allogeneic hematopoietic stem cell transplant is around 0.3%. As Mucorales are not susceptible to voriconazole and candins, and as mucormycosis often mimics aspergillosis, it is extremely important to have a precise diagnostic to correctly manage the patient. The reversed halo sign on chest computed tomography has been associated to mucormycosis in neutropenic patients, but is not pathognomonic. Direct fungal identification is crucial. Molecular approaches are developed that may be extremely useful for early diagnosis.

SUMMARY

Although randomized trials are quite impossible to run, due to the rarity of the disease, the recent numerous data have allowed the elaboration of European guidelines for the management of mucormycosis. Lipid formulations of amphotericin B, and especially liposomal amphotericin B at high doses (5-10 mg/kg/day), are the standard treatment, combined with surgery and control of favoring factors. The prognosis is poor, and any delay in the initiation of therapy may impact on outcome.

Reversed Halo Sign: Presents in Different Pulmonary Diseases

OBJECTIVE

To observe the incidence of reversed halo sign in different pulmonary diseases and the pathological correspondence of reversed halo sign.

METHODS

Retrospectively studied the high resolution computer tomography scans of all the patients who were admitted in our department with abnormal pulmonary imaging, from 1st of January 2011 to 31st of December 2013, and all the cases with reversed halo sign on the high resolution computer tomography were collected. Clinical data such as pathological findings and confirmed diagnosis of the patients with reversed halo sign on the high resolution computer tomography scan were collected and summarized.

RESULTS

Of 1546 abnormal High resolution computer tomography scans 108 had a reverse halo sign present, including 108 cases were observed with reversed halo sign in the high resolution computer tomography, including 40 cases of pulmonary tuberculosis, 43 cases of cryptogenic organizing pneumonia, 16 cases of lung cancer, 7 cases of sarcoidosis, and 1 case of pulmonary cryptococcosis, 1 case of granulomatosis with polyangiitis. Reversed halo sign had a higher incidence in granulomatous diseases (16.28%) compared with non-granulomatous diseases (9.97%).

CONCLUSIONS

Reversed halo sign is relatively non specific; it can be observed in different lung diseases, and different phases of diseases; reversed halo sign is more commonly found in granulomatous diseases compared with non-granulomatous diseases, and is most commonly observed in pulmonary tuberculosis among the granulomatous diseases, and in cryptogenic organizing pneumonia among the non-granulomatous diseases.

Organizing Pneumonias

Organizing pneumonia is a particular type of inflammatory and reparative reaction of the lung parenchyma characterized by fibroblast proliferation in the distal airspaces with overall preservation of the lung architecture. When microscopic, it is an asymptomatic and nonspecific reaction of little clinical significance accompanying many pathological processes. When macroscopic and affecting large portions of the lung parenchyma, it manifests by restrictive ventilatory defect and gas exchange impairment leading to dyspnea, cough, hypoxemia, alveolar opacities at chest imaging, and symptoms of systemic inflammation such as fever, malaise, and weight loss. This picture constitutes the clinico-pathological syndrome of organizing pneumonia, which has been recognized and characterized as a distinct entity in the past 30 years. Although the classical features of organizing pneumonia are increasingly familiar to chest physicians, and the efficacy of corticosteroid treatment makes it appear at first sight as an easy problem to resolve, atypical clinical presentations, similarities with other diseases, severe forms, histological variants, side effects of therapy, and relapses can make the management more difficult than initially expected. This chapter will address the classical and less common features of organizing pneumonia, and will provide practical clues to the diagnosis and management of this disorder.

Invasive mold infections in solid organ transplant recipients

Invasive mold infections represent an increasing source of morbidity and mortality in solid organ transplant recipients. Whereas there is a large literature regarding invasive molds infections in hematopoietic stem cell transplants, data in solid organ transplants are scarcer. In this comprehensive review, we focused on invasive mold infection in the specific population of solid organ transplant. We highlighted epidemiology and specific risk factors for these infections and we assessed the main clinical and imaging findings by fungi and by type of solid organ transplant. Finally, we attempted to summarize the diagnostic strategy for detection of these fungi and tried to give an overview of the current prophylaxis treatments and outcomes of these infections in solid organ transplant recipients.