Radiological examination of the lung


I- Introduction :

In terms of’pulmonary exploration, Chest radiographs remains important and is with’clinical examination the first approach, to guide the subsequent step.

II- Techniques and guidelines :

1- chest X-ray :

  • broad indications (screening, Respiratory symptoms).
  • deep breath, standing, short break time, -film distance 2 meters, posteroanterior.
  • Face +/- left profile, tangentiels.

2- intensifier :

– Kinetics of the diaphragm, irradiating technical and indicated little.

3- transthoracic ultrasound :

  • limited indications since the’air contained in the lungs inhibits ultrasound.
  • Epanchement pleural, nature d’a peripheral opacity, guiding puncture or biopsy.

4- TDM :

  • very indicated, saw the’excellent resolution contrast images (contrast between the natural’air in the lungs and mediastinal structures and parietal pleura neighboring).
  • Density, reports’mass, vascularisation, lesional balance, biopsies bench-guidées.
  • 3D reconstruction opportunity lung or the’bronchial tree, Virtual bronchoscopy, Automatic detection software lung nodules.

5- IRM :

  • Unless indicated that the scanner with respect to’pulmonary exploration.
  • ++ Masses apicales or juxta diaphragmatiques for the apprécier’vertical extension, mediastinal masses para to specify vascular reports.

6- PET scanner :

  • injection’an active radio tracer, balance sheet’extension and scalable monitoring lung cancer.

7- pulmonary Angiography :

  • Measuring pressures, first time’embolization (abundant hemoptysis, vascular malformation).

8- lung scan :

  • infusion (pulmonary embolism) or ventilation (bronchial stenosis).

9- bronchoscopy :

+/- biopsy.

III- Radio normal anatomy :

1- anatomy (Fig.1) :

  • right lung : 3 lobes / left lung : 2 lobes.
  • Les lobes are séparés par des scissures :

– Large lobes à droite et à gauche visibles sur le profil.
– Petite lobes Upton visible on the profiles and the face.

  • pulmonary segments :

– To the right : 3 the upper lobe level, 2 lobar means and 5 lower lobar.
– To the left : 5 upper lobar (3 the summit and 2 lingula) and 5 lower lobar.

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Fig. 1 : normal anatomy of the lungs.

2- Radio normal anatomy :

Fig.2 : the 4 radiological densities.
  • It exists 4 Main radiological densities are in ascending order : air, fat, water and calcium (Fig.2).
  • The lung is radiolucent (almost black) because it contains the’air.
Fig.3 : criterion of symmetry.
  • Impact face :

Criteria of good quality :
– Strict symmetry or face (Fig. 3) : the distance between the’inner end of the clavicle and the line of spinous processes vertebral is equal between the right and left.
– deep breath : we must rely 6 previous rib arches at each lung field, c’Thus the sixth arc right anterior costal must cross the top of the right diaphragmatic dome.
– normo penetrated: retro barely visible vertebrae heart and heart supra vertebrae clearly visible.
– Standing position : gastric air pocket must contain a level horizontal.
– Shoulder blade well clear not encroaching on the lung parenchyma.
– One can also add a sixth criterion: the costophrenic dead ends must be taken on the plate.

Analysis :
– containing : bone frame, soft tissue and diaphragmatic cupolas (the right is higher than the left)
– contents : lungs, mediastinum including heart and trachea, hiles, culs de sac pleuraux and small lobes.

  • profile Impact :

Analyze the lungs, bags gape pleural, clear retro retro heart and sternal areas, mediastinum, All scissures, bone frame (sternum and spine).

Fig.4 : the upper edges merge opacities : they are in the same plane, lower opacities edges are not the same: they are in different planes.

3- pathological semiotics :

Sign silhouette :
– When two water density structures are in contact in the same plane, they merge.
– Used to locate a mediastinal abnormality or lung compared to different anatomical structures.
– Ex : pulmonary opacity erases one edge of the heart lies in the same plane as the heart, c’is to say that’it predates.



Fig.5 : alveolar syndrome, containing a broncho gramme and a limit scissurale.

alveolar syndrome :
– Translated alveolar fluid filling (ex : OAP, pneumonia), tissue (bronchoalveolar cancer) or hemorrhagic.
– Nodular opacities blurred, confluent, contiguous confluence with places, systematized with broncho gram (Fig.5) or alvéologrammes (bronchi and alveoli clear within the’opacity), sometimes limit scissurale.

→ interstitial syndrome (and Fig.6 7) :
– Indicates a water or cellular infiltrate the pulmonary connective tissue (ex : fibrosis, Kerley lines in’OAP, sarcoïdose, lymphangite carcinomateuse).
– Opacities of varying size, net, be streamed, lack of broncho gram or’alvéologramme, not systematized, they erased the outlines perished bronchial vascular, Variable morphology can be reticular or nodular or finally honeycomb in fibrosis.

Fig.6 : interstitial syndrome reticular right in honeycomb left.
Fig.7 : micro nodules diffuse interstitial syndrome type : miliary tuberculosis.
Fig.8 : syndrome cavitaire : different possible aspects.

Syndrome cavitaire (Fig.8) :
– single or multiple cavity within the lung parenchyma that may contain’air alone or in combination with the liquid level in this case a air-fluid, the wall is of’thickness and regularity variables.
– multiple etiologies : tuberculous cavity, cancer excavé, emphysematous bubble, abscess.



Fig.9 : bronchial syndrome type atelectasis.

bronchial syndrome (Fig.9) :
– Translated or bronchiectasis (DDB), either a bronchial wall thickening (chronic bronchitis) atelectasis or by variable airflow obstruction due to (tumor, foreign body, compression by a adenomegaly).
– L’atelectasis is presented as a systematized opacity segmental or lobar, retractile concave edges attractive mediastinum, the diaphragm and the adjacent sulci.

Fig.10 : bronchial syndrome type atelectasis.

pleuro-parietal syndrome (Fig. 10) :
– Translated pleural lesion (outpouring, tumor) or parietal (metastasis, tumeur rib).
– opacity device, without bronchopulmonary gram, gradually connected to the wall, combines bone loss if it is to’parietal origin.



Fig.11 : mediastinal syndrome.

mediastinal syndrome (Fig.11) :
– Translated pathology developed from the mediastinum (goitre, adenomegaly, lymphoma, abscess para vertebral, mega esophagus).
– Opacity water tone convex outer edge to the lung, drowned in inner edge in the mediastinum while connecting with it is gently sloping, lack of broncho gram.

Cours du Dr THINGS M.R. – Faculty of Constantine