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Johan Rey P. MonPost-Graduate
InternMEDIASTINUM
NORMAL RADIOGRAPH
Narrow, vertically oriented structure that resides between the medial parietal pleural layers of the lungs
Extends from the sternum to the bodies of the vertebrae; and from the superior thoracic aperture to the diaphragm
Contains the thymus gland, the pericardial sac, the heart, the trachea and the major arteries and veins
MEDIASTINUM
BOUNDARIES
Boundaries Anterior – sternum and
costal cartilages
Posterior – 12 thoracic vertebrae
Superior – thoracic inlet
Inferior – diaphragm
Lateral – mediastinal pleura
BOUNDARIES OF THE MEDIASTINUM
DIVISIONS
Superior mediastinum*
Inferior mediastinum Anterior
- anterior to the pericardial sac and posterior to the body of the sternum
Middle- contains the pericardial sac and its contents
Posterior- posterior to the pericardial sac and the diaphragm and anterior to the bodies of the vertebrae
DIVISIONS OF THE MEDIASTINUM
Boundaries ContentsAnterior Mediastinum (Prevascular)
Superiorly - by the thoracic inlet, Laterally - by the pleura, Anteriorly - by the sternum, and Posteriorly - by the pericardium and great vessels
Internal mammary vesselsInternal mammary ad prevascular lymph nodesThymus
Middle Mediastinum (Vascular)
Anteriorly - by the anterior mediastinum Posteriorly - by the posterior mediastinum.
Heart and pericardiumAscending and transverse aortaMain and proximal right and left pulmonary arteriesConfluence of pulmonary veinsSuperior and inferior vena cavaTraches and main bronchiLymph nodes and fat within mediastinal spaces
Posterior Mediastinum (Post-vascular)
Lies behind the heart and pericardium and extends from the level of the thoracic inlet to the 12th thoracic vertebra.
Descending aortaEsophagusAzygos and hemiazygos veinsThoracic ductSympathetic ganglia and intercostal nervesLymph nodes
MEDIASTINAL CONTOUR
Right paratracheal stripe seen in two thirds of normal films made up of right brachiocephalic
vein and SVC
Arch of the azygous vein
Ascending aorta
Superior vena cava (SVC)
Right atrium
Inferior vena cava (IVC)
RIGHT CARDIOMEDIASTINAL CONTOUR
Left paratracheal stripe made up of left common carotid
artery, left subclavian artery and the left jugular vein
Aortic arch +/- aortic nipple (left superior intercostal vein)
Pulmonary artery
Auricle of left atrium
Left ventricle
LEFT CARDIOMEDIASTINAL CONTOUR
Superior mediastinum Great vessels Thymus
Ascending aorta
Right ventricular outflow track
Right ventricle
ANTERIOR CARDIOMEDIASTINAL CONTOUR
Left atrium and pulmonary veins
Right atrium
Inferior vena cava
POSTERIOR CARDIOMEDIASTINAL CONTOUR
Consists of potential spaces used to describe the location of disease processes
Important diseases change the appearance of the aortic knuckle, the aorto-pulmonary window and the right para-tracheal stripe
MEDIASTINAL CONTOURS
The aortic knuckle (red line) represents the left lateral edge of the aorta as it arches backwards over the left main bronchus, and pulmonary vessels.
The contour of the descending thoracic aorta (yellow line) can be seen in continuation from the aortic knuckle.
NORMAL AORTIC KNUCKLE
The aorto-pulmonary window lies between the arch of the aorta and the pulmonary arteries.
Between the Aortic Knuckle (AK) and the Left Pulmonary Artery (LPA)
The descending aorta (DA) marks its posterior boundary.
AORTO-PULMONARY WINDOW
From the level of the clavicles to the azygos vein the right edge of the trachea is seen as a thin white stripe.
Normal: <3 mmThickened: may represent
paratracheal mass or enlarged lymph node
RIGHT PARA-TRACHEAL STRIPE
MEDIASTINAL MASSES
ANTERIOR MEDIASTINAL MASSES
MIDDLE MEDIASTINAL MASSES
MIDDLE MEDIASTINAL MASSES
POSTERIOR MEDIASTINAL MASSES
POSTERIOR MEDIASTINAL MASSES
HILUM
• Junction of the lung with the mediastinum and is composed of upper lobe pulmonary veins and branches of the pulmonary artery and corresponding bronchi
• On chest radiographs, the term hilum represents the composite shadow of the bronchi, pulmonary arteries and veins, and lymph nodes on the medial aspect of each lung.
• Left hilar shadow is higher in the right in 90% of individuals
HILUM
On a true lateral radiograph, the right and left hilar shadows are not completely superimposed and comprise a combination of the right and left pulmonary arteries and the superior pulmonary veins
Inferior hilar window- An avascular aspect of the composite hilar shadow, inferior to the shadow of the right pulmonary artery and veins and anterior to the descending left pulmonary artery and left superior vein
LEFT LATERAL VIEW OF THE HILUM
HILAR MASS
RUL bronchus is seen in approximately 50% of individuals as an end-on, round lucency at the upper margin of the composite hilar shadow
Recognition of this bronchus, when not visible on prior radiographs, should suggest a mass or lymph node enlargement about the bronchus
LEFT LATERAL VIEW OF THE HILUM
HEART
• It lies primarily in the anterior left hemithorax, with the LV lying on the left hemidiaphragm
• The RA extends to the right of midline as it receives systemic blood from the SVC, IVC, and coronary sinus
• The RA and RV lie primarily anterior to the planes of the LA and LV
• The RV is the most anterior chamber and abuts the sternum
• The LA is subcarinal and midline in the thorax
HEART
HEART
CARDIOMEDIASTINAL ANATOMY(PA VIEW)
1. Superior vena cava2. Right atrium3. Inferior vena cava4. Aortic arch5. Main pulmonary artery6. Left atrial appendage7. Left ventricle
CARDIOMEDIASTINAL ANATOMY
(LATERAL VIEW)
1. Left atrium2. Left ventricle3. Inferior vena cava4. Right ventricle5. Right pulmonary artery6. Left pulmonary artery7. Aorta
Refer to the bulges of the cardiomediastinal contour on frontal chest radiographs.*
Right cardiomediastinal border: the right atrium is the only
normal bulge
MOGULS OF THE HEART
Left cardiomediastinal border: 1st mogul- uppermost, located paratracheally
above the carina, and formed by the aortic arch (aortic knuckle or knob)
2nd mogul- located just above the left main bronchus and represents the main pulmonary artery segment
3rd mogul- NEVER NORMAL if present, it lies below the left main
bronchus and is usually formed by prominent left atrial appendage, which is commonly seen in rheumatic heart disease
MOGULS OF THE HEART
4th mogul- bulge just above the diaphragm formed by the left ventricular margin or cardiac apex
5th mogul- bulge at the cardiophrenic angle- may be caused by prominent pericardial fat pad, pericardial cyst, or adenopathy
MOGULS OF THE HEART
Right cardiac borders:1. Superior vena cava2. Inferior vena cava3. Right atrium
CARDIAC BORDERS
Left cardiac borders:1. Aortic knob2. Main pulmonary trunk3. Left ventricle
CARDIAC BORDERS
RA LVRV
LALV
HEART CHAMBERS
Heart size is assessed as the cardiothoracic ratio (CTR)
Determines the relation of the heart to the width of the chest at its widest part near the level of the diaphragm
Cardiac size is measured by dropping parallel lines down both sides of the heart, at the most lateral points on each side, and measuring between them.
Thoracic width is measured by dropping parallel lines down the inner aspect of the widest points of the rib cage, and measuring between these.
CARDIOTHORACIC RATIO
AdultPA view = 0.50AP view = 0.55
PediaAge (wks) Range0-3 0.60-0.504-7 0.64-0.528-15 0.62-0.5116-23 0.62-0.5124-31 0.61-0.5032-39 0.61-0.5140-47 0.60-0.4948-55 0.57-0.49
Age (yrs) Range0-1 0.65-0.391-2 0.60-0.392-3 0.50-0.393-4 0.52-0.404-5 0.52-0.405-6 0.50-0.407 0.49-0.438 0.49-0.429 0.49-0.4110 0.49-0.4311 0.49-0.4312 0.46-0.40
CARDIOTHORACIC RATIO NORMAL VALUES
THANK YOU!!!
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