Imaging and differential diagnosis of pneumonia

Identification of acute pneumonia. According to X-ray and the general morphology of the pathology, pneumonia is divided into lobar pneumonia, bronchopneumonia, and interstitial pneumonia.

The value of plain x-rays for pneumonia

It can determine whether there is a lesion in the lung, determine the location of the lesion, determine the extent of the lesion, understand the dynamic changes of the lesion, understand whether there are comorbidities, observe the treatment effect and judge the prognosis.

The diagnosis of pneumonia is based on clinical and etiological examination, and imaging studies can provide a possible range of differential diagnoses.

CT examination is mainly used for the diagnosis of pneumonia complications and cases where X-ray diagnosis is difficult.

Human avian influenza pneumonia is mainly examined by plain x-rays.

The experience of SARS prevention and control proves that digital imaging technology has high application value, can improve image quality, and can prevent cross-infection.

1. Imaging manifestations of human avian influenza

1. When pneumonia has not yet appeared, there may be no abnormal manifestations on chest X-ray.

As the disease progresses, the vast majority of patients develop abnormal chest imaging findings (with pneumonia).

Patient 1: 9-year-old girl. Presents with severe diarrhoea,epilepsyseizures, coma, normal chest x-ray (panel A), death the next day.

2. Lesion morphology

The lesion morphology is divided into patchy shadows, large patchy shadows, and patchy fusion images. The density of the lesion is the density of lung consolidation and ground-glass density, and "air bronchial signs" can be seen in the lesion. Lung markings are thickened and blurred. Images of lung consolidation generally do not show morphological distribution by lobe or segment.

Patient 1 (Panel A): An 11-year-old girl showed consolidation in the right lung and patchy infiltrates in the left lower lobe on chest x-ray 6 days after onset.

3. Lesion location

Lesion images are located in both lungs, and lesions can be found in both upper and lower lung fields. Most of the time, the lesions appear diffuse in both lungs.

Early manifestations

Early manifestations are focal consolidation in the lungs with localized flaky opacities or scattered flocculent opacities that may involve lobes, segments, or lobules.

Cases of progression

In severe patients, intrapulmonary lesions progress rapidly, and the lesions progress rapidly and enlarge in a short period of time, with diffuse infiltrates in one or both lungs, showing large patches of ground-glass opacities and lung consolidation images, in which air-containing bronchial signs can be seen. Later stages of the lesion are diffuse consolidation in both lungs, and a few may be combined with unilateral or bilateral pleural effusions.

4. The speed of change of the image

Early onset:

There are small patches of ground-glass images in the lungs, which can be single or multiple.

Progression stage:

The extent of the lesion is enlarged, and it is a large patch or multiple and diffuse lesion in both lungs, and the lesion density is increased. ARDS may be present, with diffuse consolidation shadows in both lungs.

Absorption Period:

Generally, after 2~3 weeks of onset, the shadow range decreases and the density gradually decreases. Although some patients have significantly reduced or disappeared clinical symptoms and chest X-ray has returned to normal, HRCT examination still shows a faint ground-glass density image in the lungs, which can be maintained for a long time.

Pathogen: Mycoplasma pneumoniae, accounting for 27.5% of pneumonia in childrenClinical manifestations: fever, cough, sputum production, sore throat, headache, fatigue and general malaise Pathology: inflammation of the bronchi and bronchioles, edema of mucosa and surrounding lung tissue, congestion, leukocyte infiltration, alveolar inflammation and lung consolidation, inflammatory infiltration of alveolar septum.

4. X-ray findings:

Thickened, blurred, localized, or extensive patchy blurred images of lung textures, often ground glass density or lung consolidation density, may or may not be distributed by lobes and segments. Lung segments or large shadows. It can be located in the inner, middle, and outer bands of the lung field. Single or multiple, common in the middle and lower lung fields.

CT findings

Patchy images, nodular opacities and thickening of bronchial vascular bundles, reticular opacities, and K-B lines.

Male, 53 years old, exposed to rain on the 14th, fever of 39.5 degrees on the 17th, WBC6000-5000,

3. ARDS

ARDS is a clinical syndrome caused by multiple causes. Severe human avian influenza pneumonia can cause ARDS,

A good understanding of their x-ray findings is required.

Typical imaging findings of ARDS

It is a diffuse alveolar consolidation image in the lungs.Chest x-ray may be unremarkable or small patches of indistinct opacities within the first 12 hours of onset. Lesion progression: rapid progression, from small patchy shadows to multiple flaky and fused shadows, or diffuse shadows, with ground-glass density and consolidation density, and in some cases, the distribution of the peripheral part of the lung field is more obvious. Extensive lung consolidation results in a generally marked increase in the density of both lungs, with only a small amount of translucent opacity at the apex of the lungs and the costo-diaphragmatic angle, and this imaging manifestation is called "white lung". There may be a small pleural effusion. The heart size is usually normal.

ARDS

Male: 60 years oldKidney failureMultiple organ failure

Comorbidities of ARDS

Treatment with positive end-respiratory pressure (PEEP) can cause comorbidities such as pneumothorax, pneumomediastinum, subcutaneous emphysema, and pulmonary balloons.

In the later stages of the lesion, lung infection may be presented, resulting in uneven density of shadows in the lungs, cavities, and effusions.

ARDS should be distinguished from pulmonary edema

Alveolar pulmonary edema

Lesions occur in the center or base of the lungs. In the upright position, there is a clear basal distribution trend.

Pulmonary edema

Alveolar pulmonary edema is performed in the supine position, with lesions predominantly posterior, and may appear on chest x-ray as a centrally distributed sphenoid-wing consolidation shadow

4. The diagnostic value of chest X-ray

Etiological examination is required for the definitive diagnosis and exclusion of human avian influenza pneumonia.Plain x-rays are the first to detect lesions, and X-rays should be fully utilized before the etiological diagnosis is made.

(1) Reasons for the difficulty in diagnosis of chest X-ray

Diagnostic difficulties on chest x-ray are mainly seen in two areas:

1. Without understanding the epidemiological history, human avian influenza pneumonia is often diagnosed as common pneumonia, and because the initial lesion is mostly localized, it is most often mistaken for lobar pneumonia.

2. When there is a history of contact with dead poultry, ordinary pneumonia may be diagnosed as human avian influenza pneumonia, such as 1 case reported in Hunan, but the disease is eventually excluded.

(2) Give full play to the role of chest X-ray diagnosis for this disease

Imaging tests can detect lesions earlier and provide a possible range of differential diagnoses. A diagnosis is made based on the morphology of the lesion combined with the dynamic changes of a series of X-ray examinations.These include: ruling out a diagnosis, or raising the possibility of the disease.

1. According to the morphology of the lesion

Radiographic differential diagnosis of pneumonia

2. Dynamic change

Diagnosing human avian influenza pneumonia on the basis of only one x-ray is difficult. However, the dynamics of a series of X-rays can show relatively common manifestations of avian influenza in humans:

(1) The dynamic changes of the lung image rapidly,

(2) rapid progression to diffuse lesions,

(3) Rapid onset of ARDS.