Ground-glass opacity ggo pdf

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Anatolian Journal of Emergency Medicine. Approach to ground-glass opacification of the lung. Seminars in ultrasound, CT, and MR.

Highly Influential. Acute exacerbation of ILD is an acute clinical deterioration in patient with a known or not ILD, without a clear reason demonstrable at HRCT such as pulmonary embolism, edema, infection, or left heart failure [ 61 — 63 ].

There are no unique data on how often COVID lung damage develops into ARDS, but, if it does, it greatly increases the risk of in-hospital mortality [ 19 , 23 , 30 ]. Differential diagnosis could be tricky and, if clinical history and laboratory analysis are not sufficient, BAL or lung biopsy may be required. Acute exacerbation of interstitial lung disease. Patient in b shows diffuse lung involvement in GVHD after lung transplant in acute lymphatic leukemia.

Patient in c has an exacerbation of NSIP pattern in antiphospholipid antibody syndrome. Several diseases result in GGO in the setting of chronic clinical symptoms from weeks to months. The spectrum of pathologies is wide and radiological evaluation is based also on the presence of typical parenchymal signs of chronic disease such as fibrosis and architectural distortion.

Moreover, radiologists have to know the duration of symptoms, the smoking history, and other distinguishing clinical features. HRCT gives an advantage in identifying signs of fibrosis and honeycombing, which reveals a chronic process within the lung. Moreover, other entities have to be remembered, especially organizing pneumonia OP , lung involvement in drug toxicities, alveolar proteinosis, and aspiration pneumonia.

Neoplastic pathology and pulmonary involvement in sarcoidosis should also not be forgotten. NSIP occurs more commonly in association with connective-tissue disorders and other HRCT findings are traction bronchiectasis and fine basal reticulation with a typical subpleural sparing differently from COVID pneumonia [ 22 , 69 ]. Instead, a distinctive characteristic of usual interstitial pneumonia UIP pattern is the absence of GGO, except in case of an acute exacerbation, as mentioned before Fig.

Interstitial lung disease. NSIP pattern in rheumatoid arthritis with typical GGOs within reticular interstitial involvement, with focal areas of subpleural sparing a. Patient in d is a case of eosinophilic pneumonia in Churg—Strauss syndrome. In the first case, there are typical GGOs with diffuse distribution, together with cystic airspaces, lymphadenopathy, and centrilobular nodules [ 70 ].

Several CT patterns have been described as ILA, including GGO with or without interstitial reticulation, centrilobular nodularity, and traction bronchiectasis: it is important to recognize early fibrosing lung abnormalities, which are more likely to progress and to be associated with mortality [ 71 ]. One of the most common subacute-chronic lung diseases is hypersensitive pneumonitis HP : especially in the non-fibrotic form, it could be mistaken with COVID pneumonia because of its GGO distribution, but the presence of air-trapping and centrilobular GGO nodules both in the upper-middle lung zones are typical for non-fibrotic HP [ 72 ].

Air-trapping has a high specificity and sensitivity for HP, but it can be difficult to distinguish the normal increased lung attenuation in the expiration scan, with the diffuse increased attenuation due to GGO tracheal evaluation has a crucial role in recognizing expiratory CT scan. The late stage is fibrosing HP chronic with traction bronchiectasis and bilateral basal involvement c. Moreover, acute eosinophilic pneumonia is also characterized with bilateral GGO and consolidations with interlobular septal thickening and peripheral distribution: unless in COVID, the predominance is in the upper—middle lobes and pleural effusion is commonly reported.

Diagnosis of eosinophilic pneumonia is tricky, but a characteristic laboratory finding is alveolar and blood eosinophilia [ 75 ]. Drug toxicities involving the lung are quite common and often misdiagnosed; clinical manifestations can be variable from an acute form to mild-symptomatic lung disease.

Radiologic features and symptoms differ according to the specific histopathologic pattern of affection [ 69 , 76 ]. Some drugs can manifest their toxicity with interstitial pneumonia and differential diagnosis with viral infection could be tricky. OP could be cryptogenic or caused also by infective or other non-infective diseases post-radiotherapy, vasculitis, collagen, and interstitial lung diseases [ 77 ].

In COVID pneumonia, reversed halo sign is not a typical feature and it may occur later in disease progression. Drug toxicity and organizing pneumonia.

OP organizing pneumonia , COP cryptogenetic organizing pneumonia. Of course, increasing opacities and acute respiratory symptoms reveal an infectious disease in progression. Since PAP is caused by an abnormal intra-alveolar accumulation of surfactant lipo-proteinaceous material, BAL has both diagnostic and therapeutic role. Symptoms are usually non-specific dyspnea or cough , and sometimes, lung alterations are detected incidentally [ 22 , 83 ].

Aspiration pneumonia. The two cases in a , b show similar GGO areas in lower left lobe, with a super-imposed crazy-paving pattern: the first case a is a chronic aspiration pneumonia; instead, b is an example of exogenous lipoid pneumonia in a young patient with chronic inhalation of oily drugs for constipation confirmed with lung biopsy.

The third case in c is another example of lipoid pneumonia in elderly, with a rounded consolidation in the right upper lobe and diffuse GGO with crazy-paving in the lower posterior lobes please note also the dilated esophagus. Various neoplastic lesions have variable imaging features: in fact, both pre-invasive lesions for example adenocarcinoma in situ , early- and multifocal adenocarcinoma could manifest as pure GGO nodule, GGO with consolidation, or a solid nodule surrounded by GGO CT halo sign [ 86 ].

Also, primary pulmonary lymphoma or secondary lesions from adenocarcinoma may manifest as GGO nodules or halo sign Fig. CT halo sign could be a manifestation of lepidic tumor cell growth along the alveolar wall in adenocarcinoma, peritumoral hemorrhage, or lymphangitic spread if associated with interlobular septal thickening.

Ancillary signs usually coexist, such as pleural effusion or hilar-mediastinal lymphadenopathies. MALT mucose-associated lymphoid tissue. In fact, extensive areas of GGO are not common in lung sarcoidosis, but they may be the expression of diffuse coalescent granulomatous micronodules Fig. Rarely sarcoidosis may appear as multiple large GGO alterations [ 4 ]. However, ancillary imaging findings and a clinical assessment of the patient, as well as the evaluation of symptom onset, are essential in early diagnosis.

Especially, in this pandemic period, a multidisciplinary assessment of the patient is extremely effective in avoiding unnecessary hospitalization or reducing the risk of infection and quarantine, even among health care workers. All authors contributed to the study conception and design. The first draft of the manuscript was written by DC and EC, and all authors commented on previous versions of the manuscript.

All authors read and approved the final manuscript. This article does not contain any studies with human participants or animals performed by any of the authors. Publisher's Note. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

National Center for Biotechnology Information , U. Jpn J Radiol. Author information Article notes Copyright and License information Disclaimer. Diletta Cozzi, Email: moc. Corresponding author. Received Feb 25; Accepted Apr 7. This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source.

This article has been cited by other articles in PMC. Abstract Thoracic imaging is fundamental in the diagnostic route of Coronavirus disease COVID especially in patients admitted to hospitals.

Open in a separate window. Patients with acute respiratory symptoms Pulmonary diseases present acutely within a period of 7—10 days typically. Infections Differentiation of COVID pneumonia from other pulmonary infections could be really challenging, especially from other viral or atypical pneumonia.

Pulmonary edema Hydrostatic pulmonary edema is the most common cause of widespread GGO [ 2 ]. Patients with subtle symptoms or asymptomatic Several diseases result in GGO in the setting of chronic clinical symptoms from weeks to months. Drug toxicity and OP Drug toxicities involving the lung are quite common and often misdiagnosed; clinical manifestations can be variable from an acute form to mild-symptomatic lung disease.

Authors contribution All authors contributed to the study conception and design. Declarations Conflict of interest The authors declare that they have no conflict of interest. Ethical approval This article does not contain any studies with human participants or animals performed by any of the authors.

Footnotes Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. References 1. Fleischner society: glossary of terms for thoracic imaging. The relative frequencies of causes of widespread ground-glass opacity: a retrospective cohort. Eur J Radiol. Proposal of a low-dose, long-pitch, dual-source chest CT protocol on third-generation dual source CT using a tin filter for spectral shaping at kVp for coronavirus disease COVID patients: a feasibility study.

Radiol Med Torino ; 4 — Isolated diffuse ground-glass opacity in thoracic CT: causes and clinical presentations. Am J Roentgenol. Approach to ground-glass opacification of the lung. This indicates that they are free of any visible blockages. However, gray areas indicate increased density, meaning that something is partially filling the air spaces inside the lungs. This could be due to :. GGO can be due to many conditions. Sometimes, the cause is benign. Other times, it may be the temporary result of a short-term illness.

However, it can also indicate a more serious or long-term condition. The shape, size, quantity, and location of opacities will vary depending on the cause. Some conditions cause only one type, but others may cause a mixture. Pneumonia is a serious infection in the lungs. It can result from viruses, bacteria, or fungi. Most often , it occurs as a result of a viral illness, such as influenza flu , measles , or respiratory syncytial virus.

Another study in 54 participants found that GGO most commonly showed up in the lower lobes of the lungs as round opacities, but that as the disease progressed, it became more patchy and affected all lobes. If a person has symptoms that could indicate COVID, they should remain at home, self-isolate from others, and seek information from their local authority about getting tested.

Pneumonitis , or inflammation in the lungs, can occur if a person inhales:. Certain drugs can also cause pneumonitis and accompanying GGO.

Typically, this type of pneumonitis occurs shortly after a person begins taking a new drug. The person may also require medications and oxygen therapy. In the long term, the condition may cause chronic fatigue, weight loss, and irreversible scarring. E-cigarettes and vaping devices contain nicotine concentrates, solvents, and other chemicals.

Interstitial lung disease is an umbrella term that includes many different conditions. They all cause inflammation and scarring around the alveoli, lining of the lungs, and blood vessels. These conditions could be due to an autoimmune disease , a connective tissue disorder, or toxin exposure. The progression of interstitial lung disease varies from person to person depending on what caused it.

Treatment aims to slow the progression of the condition.