Slide 2
Divided into:
Upper respiratory tract
nose, mouth, pharynx & larynx
Lower respiratory tract
trachea, bronchi, alveoli & lungs
Thoracic cavity
RT & LT pleural cavities
Mediastinum
Lined by parietal pleura
Visceral pleura adheres to the lung tissue
Bones of thorax assist in inspiration & expiration
Sinuses are lined with respiratory epithelium & communicate with visceral cavities
Slide 4
Contains all thoracic organs except lungs
Heart occupies a LG portion of mediastinum
Heart varies in shape with age, PT position and degree of respiration.
Other organs of the mediastinum include:
Thyroid
Thymus glands
Nervous and lymphatic tissues
Slide 5
On a chest radiograph, the central mediastinum area is occupied by a large radio-opaque shadow termed the central mediastinal shadow which is the anatomical location of the heart and great vessels.
If any heart disease is suspected, it is very important to carefully examine its size, position and shape. Enlargement of the heart shadow might indicate the presence of a cardiac problem such as heart failure following a myocardial infarction.
However, the heart shadow is variable in shape even in normal subjects, mainly due to the wide variation in body build of different people. Additionally, respiration will also affect the heart shadow.
Using the image above as a key, examine the right border of the central mediastinal shadow.
In its superior parts, the right margin of the shadow represents the superior vena cava (1). This is a large vein which receives blood draining from the upper part of the body ie head, neck, upper limbs and part of the upper chest. Inferior to the superior vena cava, the border is formed by the right atrium (2) of the heart.
Inferior to the right atrium, a small part of the inferior vena cava can sometimes be identified as it enters the chest through the diaphragm, prior to returning blood to the heart (3).
Now look at the left border.
The left border of the central mediastinal shadow is formed superiorly by the prominent left projecting shadow of the arch of the aorta (4), also known clinically as the aortic knuckle.
Immediately inferior to the aortic arch is a shadow formed by the left pulmonary trunk (5). Lateral to this shadow, a larger white shadow within the lung field is the left pulmonary artery (6) shadow.
In a more inferior direction, the left border of the central mediastinal shadow is composed of the left margin of the heart shadow.
In its superior region, the heart shadow is formed by the tip of the auricle of the left atrium (7). Below the auricular shadow, the border is represented by the left ventricle (8) of the heart.
The point where the cardiac shadow meets the diaphragmatic shadow is called the left cardiophrenic angle (9).
Slide 6
- It is the most common diagnostic exam
- It becomes routine
- But it is very vital in providing information about the soft tissue, bone, pleura, mediastinum, heart and lung tissue
- Improper techniques
- Can mimic or obscure pathology .Are critical to diagnosis
Slide 8
Manual techniques are recorded to ensure similar techniques daily
Daily radiographs
Important to have consistent techniques to analyze changes in pathology after treatment
Or the progression the disease
Must have optimal kVp and mAs
Use PSP plates that eliminates many repeats for technique selection
They offer a wider latitude
kVp is increased to decrease PT dose
Must have enough to penetrate
Slide 11
- Most experts agree that adjustment of mAs is the best for F/S
- Because kVp adjustments change contrast
- With a digital system
- kVp should be adjusted to reduce PT dose
- Must be enough to penetrate part, taking into consideration additive and subtractive diseases
Slide 12
- The use of AEC requires careful thought as to the body size and where the pathologies are in relation to the sensors
- Portable AEC offers the advantage of consistent exposure accuracy, but there are less sensors
- Sensors should be carefully selected
- Activating a senor over an area that is over-aerated can result in an excessive exposure
- Activating a sensor over an are of fluid or tissue accumulation can result in an insufficient exposure.
Slide 14
- Upright:
- Places heart closer to IR
- Demonstrates costophrenic and cardiophrenic angles
- RT hemi diaphragm appears 1-2” higher than LT because of liver
- Recumbent:lower lungs obscured because of abdominal pressure
Slide 21
Diagnosis of pathology in infants within the mediastinum is difficult because the width of the upper mediastinum varies greatly with the phase of respiration.
As RT’s we encourage and welcome a crying infant in order for the lungs to fill with air. But clinically it results in additional distortion of the thymus.
It is very rare to see mediastinal masses in infants.
Mediastinum appears large
Thymus is large on healthy infant
AP- thymus extends beyond heart borders
Lateral- may fill anterior portion of mediastinum
Slide 23
Spontaneously usually arises from a sudden rise in intraaveolar pressure (from severe coughing, vomiting and straining) that causes alveolar rupture.
The air accumulates in the hilum and mediastinum.
This chest radiograph (posteroanterior and lateral view) is from a 3-year-old girl with a history of prematurity, chronic lung disease, and asthma who presented with a viral pneumonitis and persistent cough.
A chest radiograph on admission did not reveal any air leak. On the posteroanterior view, a Pneumomediastinum (arrow) is noted. Also, extensive subcutaneous air is observed.
On the lateral radiograph from the patient in Media file 2, anterior mediastinal air is observed. Left lower lobe atelectasis is also present. The child was asymptomatic and was discharged 2 days later
Radiographic appearance:
AP and PA air causes lateral displacement of the mediastinal pleura. Appears as a long linear opacity that runs parallel to the shadow of the heart border, but it is separated by air.
Lateral air is typically seen to have collected behind the sternum, extending in streaks downward and anterior to the heart.
Slide 26
- Severe Pneumomediastinum may cause air to pass from mediastinum to subcutaneous tissue
- Usually in chest and/or neck
- Diagnosed by feeling air bubbles in the skin, chest or neck
Slide 27
The chest radiograph is taken from an adolescent girl with status asthmaticus who was intubated for respiratory failure. A rim of air consistent with a pneumomediastinum may be observed along the upper left border of the heart. Subcutaneous air is observed in the soft tissues of the neck. She required very high peak inspiratory pressures (50 cm H2), which in conjunction with marked air trapping due to her asthma, caused alveolar rupture, allowing air to track to the mediastinum. A central venous line was placed.
**Radiographic appearance: Streaks of lucency outlining muscular bundles
Slide 29
Cystic fibrosis:
Generalized disorder resulting from a genetic defect as a autosomal recessive gene that affects the function of the exocrine glands.
Characterized by the secretion of excessively viscous mucus by all exocrine glands. The thick mucus results in an imbalance of sodium and chloride production and reabsorption.
Slide 30
Frontal chest X ray in CF shows diffuse interstitial disease with brochiectasis and nodular densities of mucoid impaction.
CF = cystic fibrosis
Causes generalized thickening of the linear markings throughout the lungs that, when combined with the almost invariable hyperinflation produces a similar appearance to severe chronic lung disease in adults.
Slide 31
Damage is initiated by gradual increase in secretion of the bronchial glands
Leads to obstruction of the bronchial system
Obstruction leads to staph infections, atelectasis, and emphysema
As disease progresses there is a barrel chest deformity, clubbed fingers & cyanosis
In adolescents & adults pulmonary complications include: pneumothorax, hemoptysis & RT sided heart failure.
Slide 32
Radiographs demonstrates generalized irregular thickening of linear markings throughout the lung.
Slide 34
90% of morbidity and mortality occurs as a result of respiratory involvement.
Increased life span and quality of living through the use of prophylactic antibiotics, chest percussions and bronchodilators.
New drug Danes (an enzyme) is being tested. It focuses on controlling the reproduction and reabsorption of sodium and chloride.
Slide 35
Cystic fibrosis. Multiple small cysts superimposed on diffuse, coarse, reticular pattern
Reticular pattern: Collection of innumerable linear opacities that together produce the appearance of a net.
Reticular pattern: express alteration in lung density manifested by innumerable linear streaks, irregularly arranged, giving the impression of a normal lung
Slide 36
Affects: Primarily affects premature infants especially those with diabetic mothers and those who have delivered cesarean.
Caused by immature surfactant producing system
Surfactant lowers surface tension (very important in infants
Lack of surfactant results in alveolar collapse & widespread atelectasis
Surfactant: consists of lipids, proteins, and carbohydrates that creates a high surface tension requiring less force to inflate and maintain alveoli. Made in alveolar walls.
Slide 37
In severe cases respiratory and metabolic acidosis develop because blood passing through lungs is not adequately oxygenated and its carbon dioxide is not be eliminated
Respiratory acidosis develops when there is too much carbon dioxide (an acid) in the body, primarily caused by decreased breathing.
Slide 38
X-ray - diffuse reticulogranular or ground glass appearance to lungs due to microatelectasis. Air bronchogram seen at lung bases. Pulmonary interstitial emphysema may develop with therapy.
Small airways stand out clearly against the atelectasis in the surrounding lung.
Slide 39
Brochogram sign characterized by bronchi surrounded by non-aerated alveoli
Slide 40
Sometimes surfactant is introduced intrathecally to reduce severity
Once surfactant is present it resolves in 4-5 days
Usually surfactant production will begin spontaneously within days of birth
Slide 44
Infiltrates -the diffusion or accumulation of substances not normal to it or in amounts in excess of the normal.
Slide 47
Bronchopneumonia (staphylococcal). Ill-defined consolidation at right base.
Slide 54
Alveolar pneumonia (pneumococcal). Homogeneous consolidation of right upper lobe and medial and posterior segments of right lower lobe. Note associated air bronchograms (arrows).
Air bronchogram sign is a sharp contrast between air within the bronchial tree and the surrounding airless lung parenchyma. This permits the normally invisible bronchial air column to be seen radioraphically.
Slide 55
Air-bronchogram sign in pneumonia. Frontal chest radiograph demonstrates air within intrapulmonary bronchi in patient with diffuse alveolar pneumonia of left lung.
Slide 58
Causes multiple alveolar densities which may be distributed widely and diffusely throughout both lungs. Most commonly affected areas are the upper and lower lobes, posteriorly. Appears as patchy opacification.
Slide 62
Interstitial pneumonia (viral). Diffuse peribronchial infiltrate with associated air-space consolidation obscures heart border (shaggy heart sign). Patchy alveolar infiltrate is present in right upper lung.
Slide 66
Chronic bronchiectasis. Severe coarsening of interstitial markings involves the bases and right upper lobe. Oval and circular cystic spaces, which produce a honeycomb-like pattern, are best seen in right upper lobe.
Slide 67
Chronic bronchiectasis. Bronchogram shows severe dilatation of the basal bronchi of the left lower lobe.
Slide 71
The lungs are large volume, but there has been loss of volume of both upper lobes, markedly elevating both hila with near-vertical basal arteries.
There is irregular coarse linear shadowing in the shrunken upper lobes, implying fibrosis, more on the right side. The visible apices are pulled-down, particularly the right apex. Leaving the 'apical pleural cap'.
The pleura is thickened and 'drawn-in' from the chest wall at mid left axilla. The left lung is more transradiant and the left apex is crossed by a soft tissue boundary with a well-defined inferior margin that passes laterally beyond the lung edge
The frontal chest radiograph shows widespread 1-3 mm nodules throughout the lungs. The high resolution chest CT shows multiple, randomly distributed 1-3 mm nodules throughout the lungs.
Slide 75
Miliary tuberculosis. Fine discrete nodules uniformly throughout both lungs.
Slide 76
Group of disorder that case chronic airway obstruction
2 most common are bronchitis & emphysema
Often both co-exist
Hard to identify which of the two caused the obstruction so it is given the generalized term COPD.
Others are asthma & brochiectasis
It is irreversible & results in limited air flow
Mortality rate has increased in the past 20 years due to cigarette smoking.
It is the top five most common causes of death in U.S.
# of people diagnosed has increased 60% since the 80’s
Slide 81
Chronic bronchitis.
Coned view of right lower lung demonstrates an increase in coarseness in interstitial markings. Arrows point to characteristic parallel line shadows (“tram lines”) outside the boundary of the pulmonary hilum.
Slide 82
Lung’s alveoli become distended usually from loss of elasticity or interference with expiration
Characterized by increase in air spaces distal to the terminal bronchioles with destruction of the alveolar walls
Symptoms include dyspnea (most common).
At first only on exertions
As it progresses at rest as well
Slide 84
Emphysema. Frontal (A) and lateral (B) projections of the chest demonstrate severe overinflation of lungs along with flattening and even a superiorly concave configuration of the hemidiaphragms.
Also, the size and lucency of the retrosternal air space are increased, the AP diameter of the chest is increased, and the number and caliber of peripheral pulmonary arteries are reduced.
Slide 85
Giant emphysematous bulla. Air-containing mass fills most of the left hemithorax
Emphysematous blebs. CT scan shows the destruction of lung parenchyma.
Slide 86
Very common airway disease in which widespread narrowing of airways develop
Due to the increased responsiveness of the tracheobronchial tree to various allergens
Allergens include:
House dust, pollen, molds, animal dander, foods fabrics (extrinsic asthma)
Exercise, cold, heat, and emotional upset (intrinsic asthma)
Slide 90
Calcified lesions are usually benign.
Slide 91
The edema in the throat causes a inspiratory stridor cough or a barking cough.
Slide 94
Appears as lobar or segmental consolidations that becomes globular in shape as pus accumulates
Also may appear as a round thick walled capsule containing air and fluid
Slide 95
The presence of air in the pleural cavity, results in partial or complete collapse of lung. Can occur secondary from another illness or spontaneously.
Other causes include trauma and iatrogenic reasons.
Pt may experience sudden, severe chest pain and dyspnea
Appears as a hyperlucent area with lack of pulmonary markings.
Radiographs should be taken upright, hard to see when done supine. An expiration and inspiration PA should be taken. Small pneumothoraxes may fix themselves spontaneously. LG ones may need a chest tube.
Slide 96
Refers to a condition with diminished air within lungs associated with reduced air volume. Most commonly this results from a bronchial obstruction. Air cannot enter that part of the lung supplied by the obstructed bronchus.
X-ray commonly demonstrates local increase in density caused by airless lung. Thin plate like streaks to lobar collapse
Slide 98
Refers to an abnormal accumulation of fluid in the extravascular pulmonary tissues. Can be caused by elevation of pulmonary venous pressure, attributed to LT sided heart failure, pulmonary venous obstruction, lymphatic blockage.
Other causes include uremia, narcotic overdose, exposure to noxious fumes, excessive oxygen, high altitudes, fat embolism, adult respiratory distress, and various neurologic abnormalities.
Edema in the interstitial space causes a loss of normal sharp definition of pulmonary vascular markings. Thin horizontal lines that represent fluid interlobular septa.
Slide 103
Occurs from asbestosis. Develops from improperly protected workers engaged in manufacturing asbestos products, in handling building materials or working with insulation composed of asbestos.
Pleural thickening appears as linear plaques opacify. Calcified plaques appear in the form of curvilinear densities conforming to the upper surfaces of the diaphragm bilaterally.
CT best demonstrates the developing pleural plaques.
In lungs round or irregular opacities produce combined linear and nodular pattern that obscures the hearts border, producing the so-called shaggy heart.
Slide 104
Refers to the inability of the heart to propel blood at a rate and volume sufficient to provide adequate oxygen to tissues.
Cardiomegaly is present on x-rays. Severe edema and pulmonary congestion.