NORMAL CHEST X RAY

How to obtain a good quality chest radiography (1) 3  aspects are very important for good quality: The penetrating power of the x-ray beam (adjustment of x-ray tube voltage ) The x-ray tube current (milliampere) The exposure time adjustment

How to obtain a good quality chest radiography (2) The adjustment of the x-ray tube voltage controls the contrast: the difference of density levels of the different organs and tissues in the thorax The x-ray tube current and the exposure time controls the intensity of x-ray beams

How to obtain a good quality chest radiography (3) Adjustment of voltage High voltage: a range of 100 /120 kV: optimal contrast between lungs and bones, and good visualisation of mediastinum and vessels Exposure time <0.05 seconds: decrease of motion artefact caused by the beating of the heart or respiratory movement

How to obtain a good quality chest radiography (4) A long distance between the tube focus and the film improves the image clarity and decreases the geometric blur

How to obtain a good quality chest radiography (5) Other criteria Quality of the x-ray grid: the flat metallic plate with very narrow lead trips close to the film: increase in the image clarity and reduction of the scattered radiation from the patient Good quality electrical power supply Efficient and frequent maintenance of x-ray equipment Quality of films and good conditions of storage Good screen-film system Good techniques for x-ray film processing (developing, rinsing, fixing, washing and drying procedure). If possible automatic film processor.

What about digital X ray system?(1) (Direct Digitalised System) composed with: Electronic flat-panel X ray detector High resolution grayscale diagnostic display High performance computer

What about digital X ray system ?(2) Avantages: -feasible imaging quality adjusted by computer processing -easy and quick image processing -X-ray film and its processing procedures in dark room no more needed. -Lower dose radiation - imaging transmission and intepretation via internet to referent radiologist is easily possible Disadvantages: - Costly initial investment (61000 to 400000 $) - Significant trainning in digital technology needed for the radiological technicians and costly running maintenance

Possible compromise with computed radiography (CR system) digital radiography using a Photo‐stimulable Phosphor plate (PSP, also called Imaging Plate, IP) enclosed in a cassette as a detector, instead of a film‐screen. The IP is then introduced into a CR Reader which reads the film and converts the recorded signal into a digital grey scale image Same avantages than digitalised system Lower cost than DR system, because can be used with the existing X ray equipment. Only a CR reader and CR cassette reader (with Imaging Plates) need to be purchased..

Basic radiographic views: Postero-anterior view Lateral view Additional/supplementary view: radiography in expiration radiography in supine and lateral position Back view (antero-posterior view) Opacification of the oesaphagus

The thorax is composed of: Bone (vertebrae, ribs, scapula…). The main component is calcium, which absorbs the x-ray considerably: the bone image is very opaque (white on the radiography) Blood and soft tissue (heart, mediastinum, vessels). The absorption of x-rays is less complete than bones: the image is less opaque (light grey) Fat tissue. the absorption of x-rays is lower: the image is dark grey. Air (in lungs) which does not absorb the x-ray at all. The image of the lungs is black

Picture of 4 different solutions on a chest x-ray film calcium water oil Air

calcium Fluid / soft tissu air Fat

Dosage of x-rays type of investigation Equivalent of chest x-ray Equivalent of natural radiation chest x-ray 1 3 days TDM 10 -100 1 month-1year NMR: no radiation

Chest x-ray: criteria for quality Deep inspiration Adequate contrast / density Good position of the patient X-ray beam in postero-anterior view (the patient is standing)

Same patient with deep inspiration Poor inspiration False opacity of the inferior lobes Adequate inspiration if you can count 9 posterior or 6 anterior parts of ribs over the diaphragm

PA is the correct view false cardiomegaly AP versus PA view clavicles are high and horizontal The x-ray beam is antero posterior Same patient with correct postero-anterior x-ray beam incidence PA is the correct view The technician should specify the position of the patient if AP view

The heart outline is bigger on D2 ( bird’s-eye view of the patient)

Correct standing or sitting position for chest radiography

Standing or sitting position not always easy to obtain…

If the patient is in supine position (too ill to stand up), the cardiac outline and mediastinum is enlarged. The scapula may be on the lung field. The chest x-ray has poor quality for analysis

The technician should specify the patient position if supine Standing patient with postero-anterior X ray beam Patient in supine position The technician should specify the patient position if supine

Dark film Lighy film no detail visible in the lung area Under penetration No detail visible in the mediastinum area.

Correct density and good contrast: - Pulmonary vessels visible in the lungs, behind the diaphragm and behind the heart Para-aortic line visible - Vertebra visible behind the mediastinum

Conditions for adequate contrast / density Correct x-ray factor (Kv, Mas, exposure time) Good conditions of developing and good quality of processing chemicals Correct temperature of developer correct quality of film In case of digitalised or computerised system, imaging quality is adjusted by computer processing and the 3 last conditions are no more needed.

Exact front view : the vertical line connecting the spinous process of thoracic vertebrae is in the middle of the two sterno-claviculars joints.

exact PA view left anterior oblique position

Front View l a o r a o D1 D2 D3 D3> D1>D2

Chest x-ray: to ensure top quality deep inspiration adequate contrast / density correct position of the patient (exact front view) x-ray beam in postero anterior view (the patient is standing)

Process for analysis of the chest radiography: the check list Verification of name and date Clinical history and findings Verification of the factors for good quality Assess -thoracic wall and thoracic skeleton - mediastinum - each lung field, one after the other Do not skip any item in the checklist !

Normal chest radiography and some pitfalls… ( trouble-shooting)

Thoracic wall And skeleton

Sternocleidomastoid muscle Thoracic wall Sus and retro clavicular field External side of Sternocleidomastoid muscle

thoracic wall 1 3 The clavicles are projected on the level of the 3rd or 4th posterior part of ribs 4

Cervical ribs: minor malformation

Be aware of foreign body or artefacts on the chest x-ray trap picture: opacity of the superior part of right lung due to a hair braid

Breast implant

The retro-clavicular fields are always difficult to analyse, because of bone superposition: - Clavicles - Anterior part of first rib - Posterior part of third and fourth rib, - Sterno-clavicular joint

There are 2 ways to correctly analyse the retro-clavicular fields: Always compare right and left Ask for a chest x-ray with the patient’s back against the film (AP view, lordotic position)

Always compare left and right Right TB infiltrate

Patient with fever, cough, AFB sputum positive…

You have no CT scan. So use your eyes and compare right and left! If any doubt, request AP/ lordotic chest X ray

Normal AP chest x-ray, back close to the film Normal chest x-ray , front close to the film

Chest x-ray, back close to the film And clavicles out of the field by raising hands Chest x-ray, front close to the film

Chest x-ray back close to the film

physiological blur of the inferior side of the ribs Thoracic wall physiological blur of the inferior side of the ribs Rib view section

You must always « read » a chest x-ray with methodology: Example: for the chest wall, you must look at every rib, one after the other (6th and 9th ribs missing on this CXR)

Chest wall Top of the axillar hole Big pectoral muscle

thoracic wall Scapula

What is wrong with this chest x-ray? Congenital clavicles agenesy

Thoracic wall Breast silhouette

Be careful with false opacities in the inferior lobes, consequences of breast superposition.

Chest x-ray. Before and after right mastectomy

The right side is usually higher than the left side (3cm ) Thoracic wall Diaphragm The right side is usually higher than the left side (3cm )

Component elements of Mediatinum and hilus

AO AO PA LA RV RA RV LV LV

Front view Lateral view AO SVC AO PA PA LV RA LA RV LV Front view Lateral view SVC: superor vena cava AO : aortic vessel PA: pulmonary artery RA:Right ventricle LV left ventricle LA: left auricle RV: right venticle LA RA LV RV

Left pulmonary artery Right pulmonary artery

The pulmonary vena are not physiologiccally visible RSPV LPSV L A RIPV L V The pulmonary vena are not physiologiccally visible

Mediastinum lines X ray beam crossing thorax and mediastinum meets in some places pleural thickness, producing images on the CXR like lines defining mediastinum lines…

Too complicated And not so usefull… Mediastinum lines 1. Sub clavicle arterial line 2. Posterior mediastinum line 3. Brachio cepahalic vena line 4. para-azygos line 5. Anterior mediastinum line 6. Descending aortic line 7. Right and left paravertébral line 8. Inferior veina cava line 9. para-œsophageal line 10. para-trachéal line Too complicated And not so usefull… 6

Three of them are really important. Right paratracheal line Aorto pulmonary line Para-aortic line Three of them are really important.

Mediastinum enlargment due to fat tissu

Be aware of false enlargment of mediastinum if obesity, poor inspiration, oblique view or supine position

Trap: false mediastinum enlargment in the case of this older woman with cyphoscoliosis, in supine position

Component elements of lungs

On a normal chest x-ray, bronchi are not visible (opacification with iodin hydrosoluble solution)

…but pulmonary arteries are visible.

Small fissura Big fissura Right view

Left fissura Left view

Right superior lobe pneumonia minor fissura Right superior lobe pneumonia minor fissura Large oblique fissura posterior part

Right inferior pneumonia Large oblique fissura

Middle lobe pneumonia Large fissura minor fissura Small pleural effusion

External segment of middle lobe pneumonia

External segment of middle lobe pneumonia

Left superior lobe pneumonia

Left inferior pneumonia Left scissura

Normal lateral view

Lateral view

AO PA LA RV LV

Front view Lateral view AO SVC AO PA PA LV RA LA RV LV Front view Lateral view LA RA LV RV

Heart and Mediastinum vessels Superior vena cava Heart and Mediastinum vessels Ascending Aorta Pulmonary arteria Right ventricle Descending aorta

Heart and Mediastinum vessels Left ventricle Inferior vena cava

Mediastinum vessels Aortic arch

mediastinum vessels Descending aorta

Right pulmonary artery Mediastinum vessels Right pulmonary artery Left pulmonary artery

normal CXR Lateral view is very useful for diagnosis of mediastinal adenopathies

trachea 20 mm

Right superior lobe bronchus Left superior lobe bronchus

The «clear spaces» Retro sternal clear space Retro cardiac clear space

The «clear spaces» Retro tracheal space

enlargment of the clear spaces: Emphysema

Emphysema Normal lateral view

The retro sternal space is filled: thymoma

The retro sternal space is filled: thymoma. Normal view on the right

Diaphragm Right diaphragm Left diaphragm

Summary normal CXR

Normal frontal chest view Aortic arch (AA) Descending aorta (DA) Proximal left pulmonary artery (PLPA) Left interlobar pulmonary artery (LPA) Aortopulmonary window (AW) Left main bronchus (LB) Left atrial appendage (LAA) Left ventricle (LV) Superior vena cava (SVC) Right paratracheal stripe (RPS) Azygos vein (AV) Right interlobar pulmonary artery (RIPA) Right atrium (RA) Trachea (T) Right diaphragm (RD) Left diaphragm (LD) T T SVC SVC A A RPTS A W AV LPA RIPA LB DA RA RD LV LD

Normal lateral chest view Posteriorly: vertebral bodies (V) and intervertebral disc spaces (*) Anteriorly: retrosternal clear space (RSCS) Trachea (T) Orifice of Right Upper Lobe bronchus (RUL) appears as circular lucency projecting over the continuation of the tracheal air column Left pulmonary artery (LPA) Right pulmonary artery (RPA) Left auricle (LA) Left ventricle (LV) Right ventricle (RV) Aortic arch (AA) Postero costo phrenic angle (PCPA) Right diphragm (RD) Left diaphragm (LD) Inferior vena cava (IVC) Scapula (Sc) Retro cardiac clear space (RCCS) T Sc AA RSCS RPA LPA RUL RV LA V RCCS * LV IVC LD RD PCPA