A lil' bit of CXR

First thing you need to know is the normal appearance of the cxr you will get in normal individual. Then, you'll know what's the abnormality in the cxr in the diseased one. Know the normal, first rule.

Normal CXR: 

Here's one cxr that you'll usually get in normal individual.

And here's the labelled one, so that you'll know what's what. Normal position, normal translucency and opacity.

Another rules in cxr, the black is 'air', the white is either 'bone', 'soft tissue', or 'fluid'. You can divide the cxr into either zones (upper, middle and lower) or according to the lobes (upper, middle and lower- division according to the oblique and horizontal fissures). 

Do correct me if you find that I'm getting the wrong idea in any of these informations about cxr, ok? :P

You need to comment on the costo-phrenic angle, either it's free or not. Check for the cardio-phrenic angle and keep in mind, left hilar is always higher than the right hilar. If by any means, the left hilar is lower in position than the right one, either there's fibrosis on the right side, which pull the right hilar upwards, or there's something on the left upper side pushing the left hilar downward.

Pleural Effusion:

It appears as HOMOGENOUS OPACITY, OBLITERATING THE COSTO-PHRENIC ANGLE and RISING TO THE AXILLA.

It is either a transudate (protein content <30g/L) or an exudate (protein content >30g/L). Since it's fluid, it'll appear whitein the cxr.

Mild right-sided pleural effusion

Moderate right-sided pleural effusion

Large left-sided pleural effusion

In pleural effusion, there'll usually be mediastinal shift (to the normal site). But, if there's collapse of lung, mediastinal shift will be towards the diseased site (sucked in).

Pneumothorax:

It appears as JET BLACK TRANSLUCENCY with ABSENCE OF LUNG MARKINGS.

There are several causes for pneumothorax:
1. Spontaneous.
2. Trauma/Iatrogenic.
3. COPD.
4. Rupture of subpleurae bullae.

Notice the aerated lung, separated from the radioluscent pleural space by the visceral pleura.

Tension right pneumothorax with collapsed right lung.

In hydropneumothorax, translucency will be accompanied by opacity (+ air fluid level).

Lobar Pneumonia:

It appears as SEMI-HOMOGENOUS OPACITY +/- AIR BRONCHOGRAM.

Presents of air-bronchogram (translucent bronchi, opaque alveoli) means the pathology is within the alveoli. Consolidation means the alveoli contains air no more. Causes of consolidation including transudate, exudate, blood, HMD (Hyaline Membrane Disease) and tumour.

A right middle lobe pneumonia.

How do I know it is a middle lobe lesion, not upper or lower lobe lesion? If the lesion 'touches' the heart, it's the middle lobe. If it 'touches' the diaphragm, not 'touching' the heart, it's the lower lobe.

Right lower lobe pneumonia. 

(Noticed the 'intact' line between lung and the heart)

Bronchopneumonia:

It appears as ILL-DEFINED MULTIPLE OPACITIES of VARYING SIZES.

Bilateral Bronchopneumonia

Lung Abscess:

ROUNDED OPACITY WITH AIR FLUID LEVEL.

Left lung abscess (Middle zone), with air fluid level.

Right lower lobe lung abscess with air fluid level.

Emphysema:

I couldn't find a proper cxr for this emphysema on the net (maybe due to my lacked in experiences), but usually, in emphysematous lung, you'll find the following criterias:

1. Hyperinflation of both lung.

2. Low flat diaphragm.

3. Transverse ribs.

4. Elongated cardiac shadow.

5. Enlarged central pulmonary arteries with attenuation of the peripheral vasculature.

Ignoring the breast shadows, the above criterias can be seen. (No? Hahaa~)

Bronchogenic Carcinoma:

ROUNDED OR OVAL OPACITY WITH ILL DEFINED SPIKY BORDER +/- ENLARGED HILAR LYMPH NODES.

Right bronchogenic carcinoma (Note : The spiky border).

Posterior-anterior chest radiograph shows right upper lobe bronchogenic carcinoma and enlarged hilar lymph nodes on the right, T2 N1 M0, stage IIB.

Pulmonary Metastases:

Multiple canon ball shadows

Canon ball metastases usually comes from Choriocarcinoma or Renal Cell Carcinoma.

Pulmonary Tuberculosis:

DD of Miliary shadow:

1. TB.

2. Sarcoidosis.

3. Miliary metastases.

Pulmonary Oedema:

In pulmonary oedema, the main problem is within the vessels. The vessel is congested, the fluid escaped to the nearby alveoli (transudate). Usually it's more in the center, since the vessels are more toward the central part.

Acute intra-alveolar pulmonary oedema with bat's wings distribution.

Cardiomegaly:

DD of Cardiomegaly:

1. Cardimyopathy.

2. Multi-valvular disease (MS, MI, AI, etc...).

3. Pericardial effusion (Flask-shaped enlargement).

To know if the heart is enlarged (on cxr inspection) or not, the transverse diameter of the heart is larger than the diameter of the hemithorax.

Abnormal hilum:

Larger-Denser-Loss of concavity

Technical:

1. Vascular - Smooth

2. Lymph nodes - Lobulated

3. Bronchogenic - Spiculated

How to know if the lesion is within the mediastinum or within the lung parenchyma?

In Lymph node affection, it is continuous with the mediastinum. If the lesion is surrounded by area of translucency, means the problem is within the lung parenchyma.

Additional Info:

DD of solitary nodule:

1. Tumour.

2. Infections (Abscess, hydatid).

3. Granuloma TB.

[Miliary (.), Nodule (<3mm), Mass (>3mm)]

There's a condition called Dextrocardia with situs inversus totalis in which the organ is in mirror-positioned than the normal one. If only the cardiac is affected, it is called dextrocardia. Only.

All of these cxr pictures are not mine. 

Thank you.