Term
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Definition
| the mass of tissues and organs separating the 2 lungs, between the sternum in front and vertebral column in the back and from the thoracic inlet above and diaphragm below |
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Term
| when is a film technically adequate? |
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Definition
| if the pt has a good inspiratory effort, if it is a PA view, the pt is erect and positioned symmetrically - no rotation, there is no motion on the film and there is adequate beam penetration |
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Term
| the appearance of what ensures a good portion of the lung is visible in an x-ray (the pt has a good inspiratory effort)? |
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Definition
| visibility of 9-11 rib/rib interspaces means the pt was inspiring when the film was taken |
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Term
| what are identifiable structures on a CXR? |
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Definition
| lung fields, mediastinum/hilum, trachea, cardiac silhouette, costophrenic and cardiophrenic angles, diaphragm, ossesous structures, and soft tissues |
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Term
| what should be considered with mediastinal widening? |
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Definition
| vascular abnormality, though if bilateral - lymphadenopathy |
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Term
| what is the 1/3 - 2/3s rule? |
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Definition
| 1/3 of the heart should be on the R side of the mediastinum and 2/3 should be on the L side |
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Term
| what are the costo- and cardio- phrenic angles? |
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Definition
| the cardiophrenic angle is where the heart meets the diaphragm on both sides, and the costophrenic angle is where the lateral border of the lung meets the diaphragm |
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Term
| how much of a difference should there be between the heights of the L and R diaphragms? |
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Definition
| 1-1.5 cm (the R side may be a little higher due to the liver) |
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Term
| why is it important for the retro-sternal area to be clear? |
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Definition
| to ensure that there is air in the lung tissue |
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Term
| which is more anterior, the trachea or esophagus? |
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Definition
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Term
| how can you tell the difference between the R and L hemi diaphragms on a lateral view? |
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Definition
| the diaphragm closest to the lateral view you are looking at will have a clearer anterior margin |
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Term
| what is one benefit of the oblique view? |
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Definition
| it helps get the mediastinum off the vertebral bodies |
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Term
| how will the lungs of a pt w/COPD or emphysema appear? |
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Definition
| elongated, with the mediastinum smushed in and the diaphragms flattened |
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Term
| what should be visible on the R mediastinal border in an AP/PA CXR? |
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Definition
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Term
| what should be visible on the L mediastinal border in an AP/PA CXR? |
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Definition
| the aortic arch, the L atrial appendage, and the L ventricle |
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Term
| what composes the mediastinal contents? |
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Definition
| the heart, great vessels, esophagus, trachea, R/L mainstem bronchi, and lymph nodes |
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Term
| what generally composes the R and L borders of the heart as seen on CXR/thoracic CT? |
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Definition
| the R border of the heart is generally composed of the R atrium and the L border of the heart is generally composed of the L ventricle |
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Term
| where is the L atrium usually on CT scans? |
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Definition
| in the back of the heart, nearest to the vertebral column |
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Term
| what does a straight line where the diaphragm should be make you think of? |
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Definition
| fluid, such as a hemothorax |
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Term
| if there is a high level of radio-lucency where a lung should be and no indication of vascular markings or lobular markings, combined with an abnormal mediastinal "bump", what might you consider? |
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Definition
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Term
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Definition
| the appearance of the triangular thymus on an infant's CXR |
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Term
| what are causes of permanent mediastinal shift? |
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Definition
| pneumononectomy (structures will move in toward where lung was), post radiation, scarring, and unilateral bulbous emphysema |
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Term
| what are causes of temporary mediastinal shift? |
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Definition
| atelectasis, tension pneumothorax, and foreign body |
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Term
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Definition
| significant opacification of a lung apex, often secondary to radiation therapy |
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Term
| what are causes of tracheal deviation? |
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Definition
| scarring, atelectasis, aortic knob prominences, mass affect, and pleural effusion |
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Term
| what are causes of cardiomegaly? |
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Definition
| CHF, cardiomyopathy, pericardial effusion, and technical problems with the film (poor inspiration, AP film, or pt is supine) |
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Term
| what are causes of pneumomediastinum? |
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Definition
| tracheal rupture, esophageal rupture/tick, gas producing organisms (rare), erosion from an adjacent tumor, trauma, iatrogenic, diabetic ketoacidosis, and asthma |
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Term
| how can a lateral view help determine the cause of pneumomediastinum? |
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Definition
| it can tell you if the air is in front of or behind what you are looking at in the PA view |
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Term
| what can the mediastinum be sectioned into? |
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Definition
| anterior, middle and posterior mediastinum |
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Term
| what are the borders of the anterior mediastinum? contents? |
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Definition
| borders: the sternum anteriorly and the heart+great vessels posteriorly. contents: internal mammary vessels, lymph nodes, thymus tissue, thyroid tissue and germ cells |
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Term
| what are the four T's for anterior mediastinal masses? |
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Definition
| thyroid, thymoma, teratoma, terrible lymphoma |
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Term
| what characterizes a substernal goiter (thyroid of the terrible T's)? |
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Definition
| substernal goiters are located at thoracic inlets, cause tracheal deviation, are often calcified, and most pts are asymptomatic (though they may present w/dysphagia or dyspnea). they are often IDed incidentally on CXR and if a nuclear medicine thyroid scan is indicated, consider a non-contrast CT (nuclear medicine will interfere with iodine uptake) |
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Term
| what characterizes teratomas? |
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Definition
| they are malignant germ cell tumors that occur almost always in men, usually <40. they contain endo, ecto, and mesoderm and often fat, Ca++ and teeth. if there is also a choriocarcinoma, the increase in HCG can lead to gynecomastia |
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Term
| what characterizes the "terrible" lymphoma? |
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Definition
| hodgkins (90% cure rate w/radiation, spreads to contiguous nodal groups, and 75% occur in mediastinal nodes) and non-hodgkins (20% occur in mediastinal nodes, nodal groups are skipped, and there is a poorer prognosis) |
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Term
| what characterizes a thymomoa? |
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Definition
| these are mostly found at the junction of the heart and the great vessels, 70% are benign, 25% are calcified, there is a 15% correlation w/myasthenia gravis, and they are seen mainly in pts 40-50 yrs old |
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Term
| what are the normal contents of the middle mediastinum? |
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Definition
| the heart, pericardium, aorta, pulmonary arteries/veins, trachea, mainstem bronchi, lymph nodes, and nerves (vagus, recurrent laryngeal) |
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Term
| what are common causes of middle mediastinal masses? |
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Definition
| pericardial fat pad, bronchogenic cyst/carcinoma, diaphragmatic hernia (hiatal), dilated vessels (aneurysm), and lymphadenopathy (*most common*) |
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Term
| how would an aortic laceration, hematoma or aneurysm appear on a CXR? |
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Definition
| widened mediastinum, indistinct aortic arch, fullness in region of aortic knob extending to the L lung apex (apical capping), and tracheal deviation to the R (ET tube) |
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Term
| what are typical causes of lymphadenopathy - the most common middle mediastinal mass? |
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Definition
| bronchogenic carcinomas (unilateral/bilateral), lymphoma (bilateral), leukemia, mets, sarcoid (bilateral), infection (TB, histo, coccidio) |
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Term
| how does metastatic cancer spreading through the lymph system appear in the lungs? |
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Definition
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Term
| what are possibilities causes of calcified lymph nodes? |
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Definition
| granulomatous disease (TB, histo), pneumoconioses (silicosis, anthracosis), and treated malignancies (hodgkin's) |
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Term
| what are the contents of the posterior mediastinum? |
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Definition
| the esophagus, the descending aorta, azygous/hemiazygous, intercostal and paraspinal nerves, and the pleura |
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Term
| what are common causes of posterior mediastinal masses? |
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Definition
| neurogenic tumors, duplication cysts, lymphadenopathy, esophageal pathology, and hernia |
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Term
| what are common causes of posterior mediastinal masses? |
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Definition
| neurogenic tumors (most common), duplication cysts, lymphadenopathy, esophageal pathology (hiatal hernia), and hernia |
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Term
| what are the common kinds of neurogenic masses (all found in the posterior mediastinum)? |
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Definition
| peripheral nerves, neurofibromas, schwannomas, sympathetic ganglion, and gangliomas |
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Term
| what are common paravertebral masses seen on a CXR? |
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Definition
| abscess (S. aureus, salmonella), extramedullary hematopoesis (chronic anemia), TB (pott's disease), neurogenic tumors, and meningoceles |
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