Salient Features of India constitution especially power and functions
Thorax-XRAY and CT
1. THORAX
Normal Anatomy of Thorax
With X-Ray and CT
DR. NITIN WADHWANI
Prof. and H.O.D department of Radio-diagnosis,
DY Patil medical college, hospital & research institute Kolhapur
9. The mediastinum lies within
the thorax and is enclosed
on the right and left
by pleurae. It is surrounded
by the chest wall in front,
the lungs to the sides and
the spine at the back
Mediastinum
It contains all the organs of
the thorax except the
lungs.
10. The mediastinum can be divided into an upper (or superior) and lower (or inferior) part:
1) The superior mediastinum starts at the superior thoracic aperture and ends at
the thoracic plane.
2) The inferior mediastinum from this level to the diaphragm.
This lower part is subdivided into three regions, all relative to the pericardium –
•the anterior mediastinum being in front of the pericardium,
•the middle mediastinum contains the pericardium and its contents, and
•the posterior mediastinum being behind the pericardium.
19. *Assessing The Image Quality, “RIPE” mnemonic is used;
Rotation, Inspiration, Position, Exposure(Penetration).
•Check for rotation
measure the distance from the medial end of each clavicle to the spinous
process of the vertebra at the same level, which should be equal
•Check adequacy of inspiration
Nine pairs of ribs should be seen posteriorly in order to consider a chest x-ray
adequate in terms of inspiration
•Check penetration
one should barely see the thoracic vertebrae behind the heart
•Check exposure
One needs to be able to identify both costophrenic angles and lung apices
* “RIPE”
20. 1) Rotation: The clavicles
should appear symmetrical
and be seen as equal length.
The distance between the
thoracic spinal process and
clavicular heads should be
equal
21. 2) Inspiration: On good
inspiration, the diaphragm
should be seen at the level of
the 8th – 10th posterior rib or
5th – 6th anterior rib.
22. 3)Position: PA, AP, or lateral
view? The standard chest X-Rays
consists of a PA and lateral chest X-
Ray.
The normal lateral chest x-ray view is
obtained with the left chest against
the cassette. If the x-ray is a true
lateral, the right ribs are larger due to
magnification and usually projected
posteriorly to the left ribs (Figure-3).
23. 4) Exposure / Penetration: Ideally, you should be able to see the heart,
the blood vessels, and the intervertebral spaces. Exposure should be
adequate if you are able to see approximately T4 vertebra and spinal process.
If the film is underexposed, you will not be able to see them . If the film is
overexposed, details of bone structures will be lost .
25. Figure-7: Overexposed PA X-Ray film. You are able to see all vertebral bodies
with obvious intervertebral spaces.
26. The interpretation of a chest X-Ray should be approached
systematically. For chest X-Rays, there is a classic schematic:
“ABCDEF.” You should first check the patient’s name and date of the
film. You should also check the side marker, and the film position (PA
or AP). Finally, you should check patient’s position such as supine,
erect or semi-erect.
The analysis is ABCDEF:
•Airways
•Bones
•Cardiac
•Diaphragm
•Extra-thoracic tissues
•Fields and Fissures
Interpretation of a chest X-Ray
27. Mnemonic Explanation Note
A Airways
The trachea should be central or slightly to the right. If it is deviated, check whether it is due
to the patient's position or another pathological cause.
B Bones and soft tissues
Assess the bones visible in the image from top to bottom. The edges of the bones
should be smooth, otherwise a fracture may be indicated. Also assess for bone
density, oedema or metastatic lesion.
C Cardiac
On a PA image, the heart's width should be less than 50% of the chest width. On an AP image,
it should be between 50-60% of the chest width.
D Diaphragm
The right diaphragm is normally higher than the left. The costophrenic and cardiophrenic angles
should be clearly visible. The blunting of those angles may indicate effusion.
E Edges of the Heart The edges of the heart should be clearly defined. Otherwise, there may be
consolidation in the adjacent lung lobes.
F Fields and Fissure Check for any absence of normal lung markings in both fields. Also check for
opaque masses, consolidation, or fluid.
G Great Vessels or Assess the aorta and pulmonary vessels. The aortic knob should be visible.
Gastric bubbles A normal gastric bubble can be seen below the left diaphragm.
32. E – EXTRATHORACIC TISSUES
Mostly this means as the lung parenchyma.
Lung fields can be divided into zones: upper, middle,
and lower zones (Figure-12);
•Upper zone: from the apex to 2nd costal cartilage.
•Middle zone: between 2nd and 4th costal cartilage.
•Lower zone: between 4th and 6th costal cartilage
Chest X-ray interpretation is one of the fundamental skills of every doctor. Radiologists are particularly exposed to various chest x-rays during a regular shift. Therefore, knowing the basics and pathologies in the regular setting is very important.
The chest x-ray shows adequate inspiration.
The right ribs (red arrows) and left ribs (green arrows) on the lateral chest X-Ray.
So you should compare the lung parenchyma left to right in the upper, middle and lower zones and see whether there is a difference.
Look for equal radiolucency between the left and the right lungs zones. The horizontal fissure on the right divides the upper and middle lobes; from the hilum to the 6th rib at the axillary line.
You should also check soft tissues outside the thorax for subcutaneous air, foreign body, bizarre density, etc.
