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What does a cloudy lung x ray mean: Abnormal chest x-ray: what does it mean?

Abnormal chest x-ray: what does it mean?


Dr Konrad Grosser –


chest X-ray is an imaging test that utilises low doses of radiation in short blasts to create images of the inside of a patient’s chest. In this way, doctors can examine the heart, lungs, bones, and blood vessels.


If the X-ray images show abnormalities, this means that there is something unusual on the image of the chest. This is usually indicative of a problem, and could be immediately obvious, such as a broken or fractured rib, or could simply be a shadow that needs further investigation.

Some doctors specialise in dealing with abnormalities in chest X-ray results, and may order follow-up tests to determine the cause.


Why does a doctor order a chest x-ray?

A doctor may order a chest x-ray if a patient is presenting with symptoms such as:

  • persistent coughing
  • difficulty breathing
  • wheezing
  • coughing up blood
  • chest pain
  • chest injury
  • fever
  • shortness of breath

Other reasons a chest x-ray may be ordered is to reveal:

  • fractures
  • heart-related problems
  • problems with blood vessels
  • changes after having an operation
  • lung conditions
  • outline and size of the heart
  • position of pacemaker, defibrillator, or catheter


What causes an abnormal chest X-ray?

An abnormal chest X-ray can be caused by a number of conditions.


  • pneumonia (unusual white or hazy shadow on the normally dark lungs on the X-ray can indicate this)
  • abscesses
  • pulmonary oedema (fluid build-up in the lungs)
  • lung cancer and other masses in the lungs
  • cavities in the lungs or cavitary lesions (caused by diseases like tuberculosis and sarcoidosis)
  • bronchitis
  • asthma


  • an enlarged heart (cardiomegaly), which can, in turn, be caused by various conditions, such as hypertension or coronary artery disease.
  • heart failure
  • fluid around the heart


  • broken ribs
  • broken or fractured vertebrae
  • dislocated shoulder


  • pleural effusion (fluid build-up between the lungs and chest wall)
  • pneumothorax (build-up of air between the lungs and chest wall)
  • hiatal hernia
  • aortic aneurysm
  • cysts


What does an abnormal chest x-ray look like?

Lungs: the whiter the lungs appear on the scan, the more dense they will be; the darker they are, the less dense. A doctor will assess which side of the lungs or if both sides are abnormal based on key surrounding features.

Heart: the heart blocks radiation so will appear lightly in the scan. Any abnormalities with the heart or surrounding it will appear as lighter or darker areas.

Bones: bones are the densest natural structure seen in a chest x-ray. Fractures will be quickly and easily seen in the scan as dark lines through the bone.

A radiologist will look for clues indicating there is an abnormality and will report with the doctor who ordered the chest x-ray.


What’s the next step?

If the doctor is concerned by an abnormal chest X-ray, but doesn’t have enough information to make a diagnosis, they may order further tests, including a chest CT scan or a PET scan. By analysing the results of all these tests, the problem can be identified, and the doctor can plan a course of action with the patient to treat the condition.

Chest X-ray Abnormalities – Lung abnormalities

Chest X-ray Abnormalities – Lung abnormalities

Key points
  • Compare the left and right upper, middle and lower lung zones
  • Decide which side is abnormal
  • Compare an area of abnormality with the rest of the lung on the same side
  • The whiter side is not always the abnormal side
  • Remember many lung diseases are bilateral and symmetrical

Lung zones

Assess the lungs by comparing the upper, middle and lower lung zones on the left and right. Asymmetry of lung density is represented as either abnormal whiteness (increased density), or abnormal blackness (decreased density). Once you have spotted asymmetry, the next step is to decide which side is abnormal. If there is an area that is different from the surrounding ipsilateral lung, then this is likely to be the abnormal area.


If the alveoli and small airways fill with dense material, the lung is said to be consolidated. It is important to be aware that consolidation does not always mean there is infection, and the small airways may fill with material other than pus (as in pneumonia), such as fluid (pulmonary oedema), blood (pulmonary haemorrhage), or cells (cancer). They all look similar and clinical information will often help you decide the diagnosis.

Air bronchogram

If an area of lung is consolidated it becomes dense and white. If the larger airways are spared, they are of relatively low density (blacker). This phenomenon is known as air bronchogram and it is a characteristic sign of consolidation.

Consolidation with air bronchogram

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Consolidation with air bronchogram
  • The left middle zone is white
  • Dark lines through the area of white are a good example of air bronchogram
Clinical information
  • The patient had a high temperature and a productive cough
  • Pneumonia – consolidation with pus
Differential diagnosis of consolidation
  • Pneumonia – airways full of pus
  • Cancer – airways full of cells
  • Pulmonary haemorrhage – airways full of blood
  • Pulmonary oedema – airways full of fluid

Small lung zone abnormalities

Careful comparison of the lung zones can lead to noticing smaller abnormalities which may otherwise be ignored.

Unilateral middle zone abnormality

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Unilateral middle zone abnormality
  • The middle zones are asymmetrical
  • There is a small irregular opacity on the right
  • This opacity contains a dark area – cavity
  • Other areas of the lungs are normal
Clinical information
  • This patient had a history of intravenous drug abuse and presented with a high fever
  • Septic embolus
Differential diagnosis of lung cavities
  • Lung abscess – TB, Klebsiella or Staph aureus
  • Lung cancer
  • Septic embolus – infected thrombus
  • Fungal infection – if immunocompromised
  • Granulomatosis with polyangiitis

Bilateral lung abnormalities

Comparing sides does not always give the answer. The lungs may be abnormal on both sides and so awareness of the normal appearances of lung parenchyma becomes more important.

Bilaterally abnormal lung zones

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Bilaterally abnormal lung zones
  • Multiple bilateral lung nodules
  • Symmetrical distribution
  • More nodules at the lung bases
Clinical information
  • Shortness of breath, weight loss and clinically suspected underlying malignancy
  • Pulmonary metastases

Unilateral low density

If there is asymmetry of the lungs, sometimes it is the dark (less dense) area that is abnormal.

Unilateral black lower zone

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Unilateral black lower zone
  • Asymmetrical lower zones
  • Left darker than right
  • Lung hyperexpansion
Clinical information
  • Chronic smoker with increasing shortness of breath
  • Chronic obstructive pulmonary disease with a large left lower zone lung bulla

Page author:
Dr Graham Lloyd-Jones BA MBBS MRCP FRCR – Consultant Radiologist –
Salisbury NHS Foundation Trust UK
(Read bio)

Last reviewed:
July 2019

Lung ground-glass lesion on CT

Chest multispiral computed tomography, or MSCT, which is considered the most informative method of examining the lungs, doctors can diagnose infectious-inflammatory and oncological diseases at an early stage.

Frosted glasses are characteristic of pneumonia, tuberculosis, lung cancer and other dangerous conditions. Which ones and on what grounds distinguish them? Let’s take a closer look in this article.

What is ground glass?

Frosted glasses are areas of compaction of the lung tissue that transmit X-Ray rays worse. In another way, they are called foci of lung tissue compaction. On tomograms, such areas resemble light spots or cloudy plaque. Ground-glass foci indicate that the alveoli of the lungs are filled with fluid (transudate, blood), and not air. They may also indicate a decrease in lung pneumatization due to fibrotic changes. Alveoli are involved in gas exchange, supply cells with oxygen and remove carbon dioxide, so filling their cavity with a liquid substance or connective tissue cells is unacceptable.

If the total area of ​​”frosted glasses” increases, this indicates a progressive infectious and inflammatory disease. The patient begins to be disturbed by lack of air, shortness of breath, cough.

In what diseases does ground glass appear on tomograms?

According to the Department of Radiation Diagnostics of the Moscow Medical Academy. Sechenov, a picture of “haze” is most often given by pneumonia (viral, bacterial, fungal), however, lung infiltration is also characteristic of other pathological conditions. Here are just a few of them:

  • Alveolar proteinosis;
  • Pneumonitis;
  • Hemorrhage;
  • Granulomatosis;
  • Alveolar edema;
  • Allergic alveolitis;
  • Tuberculosis;
  • Drug-induced lung injury;
  • Lung infarction;
  • Viral infection;
  • Dermatomyositis;
  • Tumors;
  • Rheumatoid arteritis;
  • Respiratory bronchiolitis with ILD;
  • Sjögren’s syndrome;
  • Goodpasture’s syndrome;
  • Scleroderma.

Evaluating the CT data of the lungs, the radiologist differentiates diseases according to the specific pattern of “ground glasses”: their number, localization, the presence of other signs by which it is possible to determine the cause of pathological changes in lung tissue. For example, bilateral viral pneumonia is characterized by the presence of “ground glasses” located peripherally in the lower and posterior sections of the lungs. In a later stage, consolidation of infiltration foci with thickening of the alveolar septa is observed.

“Ground glasses” in tuberculosis can be located near the bronchi or disseminated – in this case, there are many small light areas (infiltrates), randomly located throughout the lung cavity. Also, with tuberculosis, CT scan of the lungs can detect characteristic fibrous bands leading to the root of the lung – this is peribronchial inflammation, signs of lymphostasis with an increase in lymph nodes. Single areas of “ground glass” of small size without a clear pattern of any disease may indicate a neoplasm, developing fibrosis, adenocarcinoma (cancer) of the lungs.

Sometimes “ground glasses” indicate vascular pathologies that lead to compression of the alveolar space. Obese patients may develop in gravity-dependent (lower) regions of the lungs when exposed to excess weight. In healthy patients, the effect of “ground glass” can appear on tomograms if the chest scan is performed on exhalation (correctly – on a deep breath).

Ignoring these errors and speaking of the true ground glass syndrome on CT scan of the lungs, we note that this is a sign of non-functional areas of the lungs. Normally, there should be no seals and obstructions for breathing, and the lung tissue is presented on tomograms as a uniform dark color. Very rarely, “frosted glasses” indicate the individual characteristics of the patient’s body, for example, the atypical location of the diaphragm in newborns. But these are isolated cases, so let’s look at the most common disease patterns in which “ground glasses” are found on tomography.

CT ground glass for pneumonia

Most often, “ground glass” on CT is manifested in pneumonia, and it can be absolutely any pneumonia: viral, bacterial, with atypical development of the symptom complex, very rare interstitial, and so on. Since the spectrum of causative agents of pneumonia is extremely wide, and it is not always possible to differentiate lung diseases by a single ground-glass effect, the patient is recommended laboratory diagnostics – a blood test or a respiratory secretion for mycoplasmas, pneumococci, coronavirus and other pathogens.

A common symptom of acute pneumonia on CT is the presence of infiltrates (“ground glasses”) of various shapes and lengths. “Ground glasses” are located around the foci or diffusely, as in tuberculosis. However, unlike tuberculosis, their size is usually larger, there is a tendency for the infiltrates to consolidate and form a “cobblestone” pattern. In some cases, the lumen of the bronchi containing gas is visualized. This is called “air bronchography” syndrome. Combined with the ground glass effect, it is also a clear sign of pneumonia.

Pneumonia caused by COVID-19 is characterized by a peripheral location of lesions under the pleura. The most vulnerable are the bilateral lower lobes and posterior sections of the lungs. There is a tendency to consolidation of “frosted glasses” and thickening of the septa of the alveoli, sometimes signs of pulmonary fibrosis.

Severe forms of coronavirus pneumonia are accompanied by acute respiratory distress syndrome. ARDS is an extensive bilateral inflammation in which there are many infiltrates and pulmonary edema. On the tomograms, fragmentary cortical ground glass areas are present on both sides and look like a patchwork quilt.

With pneumocystis pneumonia caused by the yeast-like fungus Pneumocystis Jirovecii, a slightly different picture is observed. Ground-glass lung compaction areas are usually located symmetrically on both sides (but sometimes diffusely and unevenly). Seals prevail in the basal areas of the lungs, and diffuse changes – in the upper and lower sections. Pneumocystis pneumonia, as well as viral pneumonia associated with COVID-19, is characterized by the effect of consolidation and the “patchwork quilt” symptom, but other signs are also visible on tomograms of the lungs: air cysts, pneumothorax.

A separate group of diseases is represented by idiopathic interstitial pneumonia, the cause of which cannot be established. In addition to “ground glass” on CT scans of the lungs, you can detect the symptom of “honeycomb lung”, bronchiectasis, reticular changes. Idiopathic pneumonias require histological examination.

Based on the findings of a CT scan of the lungs and the patient’s history, the radiologist will be able to determine the lesion of the lungs, characteristic of pneumonia. As part of the differential diagnosis, the density and shape of “frosted glasses”, their number are taken into account, and the picture is generally evaluated. However, it is possible to determine the causative agent of pneumonia and treatment tactics after additional laboratory diagnostics.

“Gross glass” on CT for tuberculosis

Foci of ground glass infiltration are also found in tuberculosis. It is caused by the bacterium Mycobacterium tuberculosis. It is believed that all adults who have reached the age of 30 are carriers of mycobacterium in a “sleeping” form. When the immune system is suppressed, TB bacteria can become active and the person becomes ill.

CT scan of the lungs usually shows multiple small (miliary) lesions disseminated throughout the lungs. Their concentration in a certain proportion is possible. Often there is an infiltrate in the form of a “track” leading to the root of the lung. There is an increase in lymph nodes. It is possible to finally distinguish tuberculosis from pneumonia according to the results of PCR diagnostics – a blood test for the causative agent of infectious pneumonia.

CT ground glass for pulmonary edema

Pulmonary edema is a complication of massive inflammation, sepsis, toxic poisoning. Edema often occurs as a complication of chronic and acute lung diseases, a consequence of coronary ischemia, heart failure, pathological failures in the work of other organs and their systems.

With cardiogenic pulmonary edema, along with “ground glasses”, there is a thickening of the interlobar pleura, a mesh deformation of the pulmonary pattern, and the contours of the roots of the lungs are expanded and indistinct.

Additional features of pulmonary edema on CT include enlargement of the pulmonary vessels, dilation of the heart chambers, and fluid in the pleural cavity.

Ground glass for lung adenocarcinoma (cancer)

The effect of “ground glass” on CT of the lungs determines malignant neoplasms – lung cancer. Adenocarcinoma is the most common type of tumor; a significant “trigger” for its formation is smoking, heredity, age (over 40 years).

Tumor adenocarcinoma is formed from cells of the glandular epithelium. On the tomogram, it is represented by a single, usually small (from 2 mm) area of ​​\u200b\u200bdensification of the “ground glass” type. In some cases, the patient has several “frosted glasses” of a diffuse or diffuse-mosaic type. Adenocarcinoma is represented by various morphological subtypes and requires dynamic monitoring.

Do not attempt to interpret the images yourself. To identify “frosted glasses” and give them a differentiated assessment can only be a specialized doctor, a specialist who has been trained and has an appropriate certificate.

Text prepared by

Maksim Anatolievich Kotov, Chief Physician of the Ami CT Center, Candidate of Medical Sciences, Associate Professor. Experience 21 years

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Ground glass symptom on computed tomography

Differential diagnosis

A moderately pronounced increase in the density of lung tissue or a symptom of “ground glass” (English: ground glass opacity) is found quite often on computed tomography of the chest organs.

This non-specific radiological symptom occurs in many pathologies, from viral pneumonia to bruising, pulmonary infarction, and the consequences of vaping. Only a combination of laboratory data and the patient’s clinical condition will help to make the correct diagnosis.

The causes of compaction of the lung tissue according to the type of “frosted glass” can be divided into acute and chronic. Among the acute causes are infectious (atypical bacterial and viral infections), alveolar bleeding, pulmonary edema, diffuse alveolar damage, pulmonary embolism, and some neoplasms.

Let us consider under what diseases visualization on CT can occur according to the “ground glass” type.

Alveolar bleeding

Pathology develops when the alveolar-capillary membranes of small pulmonary vessels are damaged, due to which blood accumulates in the alveoli and gas exchange is disturbed.

The reasons may be:

  • Inhalation of toxins;
  • Wegener’s granulomatosis;
  • Thrombolytic therapy;
  • Systemic lupus erythematosus;
  • Mitral valve pathologies

and many others.

When x-rays, there is a diffuse decrease in the airiness of the lung tissue, to a greater extent in the middle sections of the lungs. The CT picture largely depends on the time elapsed since the onset of the hemorrhage.

The acute period is characterized mainly by compaction of the ground glass type with a distinct visualization on CT of segmental and subsegmental bronchi. A few days later, thickened inter- and intralobular septa are added to the changes.

Pulmonary edema

Pulmonary edema is a pathological condition caused by an increase in the content of extravascular fluid in the lungs (in the interstitium and / or in the alveoli).

Clinical forms of pulmonary edema:

  • Cardiogenic – in diseases of the heart and blood vessels;
  • Non-cardiogenic – with distress syndrome, taking certain drugs (heroin, salicylates, etc.).

Visualization using tomography and radiography is characterized by plethora of the upper lobes, an increase in the cardiothoracic index, thickening of the interlobular fissures, ground-glass confluent seals in the lungs on CT, areas of consolidation with a relatively symmetrical distribution in the central sections, and bilateral hydrothorax, more often predominant on the right.

Viral pneumonia

Viruses are the most common causative agents of respiratory infections.

Cytomegalovirus usually causes an asymptomatic infection or mild flu-like symptoms. The predominant radiographic findings are bilateral and asymmetrical ground-glass opacities, small, poorly defined centrilobular nodules, and alveolar consolidations, combined with thickening of the interlobular septa.

Influenza virus (h2N1) causes seasonal infections of the respiratory tract, including the trachea and bronchi. They can be intermittent, endemic or pandemic. The main tomographic findings are unilateral or bilateral ground-glass opacities that may be associated with focal or multifocal areas of consolidation. Changes have predominantly peribronchovascular and subpleural distribution, similar to organizing pneumonia.

In March 2020, COVID-19 reached pandemic levels. The most dangerous complication of the disease is viral pneumonia. In coronavirus-associated pneumonia, bilateral ground-glass opacities, with or without opacities, are also seen on CT and x-rays, usually with peripheral extension in the posterior segments, areas of consolidation, and cobblestone patches.

Lung infarction

The main cause of the disease is pulmonary thromboembolism. Diagnosis in the acute phase is carried out in accordance with the protocol of laboratory and clinical tests.

Computed tomography angiography according to a special protocol is the gold standard for visual diagnostics, in which there is insufficient filling of the pulmonary artery and / or its branches.

Findings in lung parenchymal infarction include reversed halo opacification (peripheral consolidation and central ground glass opacification) that is wedge-shaped, with the base facing the pleura and the apex facing the hilum.

Lung contusion

In the case of a chest injury, a chest x-ray is the first study performed to evaluate pneumothorax. In negative cases, further examination with a CT scan of the chest is recommended. This method has greater sensitivity and specificity for trauma-related changes.

Pulmonary contusion is the most common lesion in non-penetrating chest injuries. It is defined as a traumatic lesion of the alveoli with alveolar hemorrhage, but without significant rupture of the alveoli.

The consequences of lung contusion by computed tomography can be visualized after 6 hours, and the resolution stage begins after 24-48 hours.

Examination of the chest organs is characterized by ground-glass opacities on CT and/or uneven seals located subpleurally (in the area of ​​traumatic impact) or on the opposite side (counterreactive injury).


Evali is a new vaping disease, a non-communicable disease associated with the consumption of electronic cigarettes. The most common finding on CT with a confirmed diagnosis of EVALI is multifocal or diffuse ground-glass opacity. The prevalence of changes often exceeds similar manifestations in subacute hypersensitivity pneumonitis or pneumonia


Ground glass opacity on computed tomography is not a rare pathology and a nonspecific symptom.