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30 Cards in this Set
- Front
- Back
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what is an x-ray? What's it made out of? |
- radiographs, or x-rays, are images which are obtained using ionizing radiation - 2 dimensional x-ray image is a summation fo all the structures trhrough which the x-ray beam passed |
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how does an x-ray work? |
- an x ray is a 2 dimensional image that is the summation of all the strutures through which the x-ray beam passed
-x -ray beam is attenuated (absorbed) by the tissues it passes through
- most structures appear as varying shades of gray. Tissues which attenuate more of the x-rays appear whiter on the image while tissues which attenuate less of the x-rays appear blacker on the image |
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what factors affect the appearance of the x-ray? |
the density of the object being imaged influences how much of the x-ray beam will be absorbed a. air, which appears black b. fat which appears dark gray/black c. soft tissues and organs, which appear gray d. metal, calcium, and bone which appear white
the thicker the structure is the most x-ray beam it will attenuate |
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how do bones appear on an x ray? how does air appear on an x-ray? how do soft tissues appear on an x-ray? |
bones appear dense and white air does not attenuate much of the x-ray beam, it appears black soft tissues appear in varying shades of gray. They are not well seen unless there is a tissue next to them of very different composition |
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abdomen x-ray |
- most of the abdomen is comprised of soft tissue structures - the gas that fills the stomach and bowel appears black and makes these structures visible - The bowel that is filled with food or fluid is not well seen, as it blends into the background gray appearance of the other soft tissue structure of the abdomen - fat is slightly more radiolucent than other soft tissues and appears blacker |
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what are the indications for chest x- ray (CXR)? |
- dyspnea - trauma - chest pain - chronic cough - pneumonia follow - up - suspected CHF
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do chest x-rays have high or low radiation? |
LOW RADIATION (she stressed this multiple times) |
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what are the strengths of a chest x-ray? what are the weaknesses of a chest x-ray? |
strengths of cxr: - low cost - readily available - low radiation
weaknesses of cxr: - low diagnosistic yield - portable - poor results in obese patients |
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what is the standard positioning for a chest x-ray? |
- posterioranterior (PA) and lateral - PA exam is viewed as if the patient is standing in front of you with their right side on your left - lateral view the patient is facing towards the left on the lateral view |
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what positioning do patients take if they're unable to do PA or lateral positioning? |
anteriorposterior (AP) view |
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anteriorposterior (AP) view |
- performed on patients who are unable to stand for the PA exam - AP radiographs are performed at bedside - the film cassette is placed under the patients back and a portable x-ray machine is positioned over the patient's chest |
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what are the cons of the AP view? |
- AP views are difficult to interpret due to many potential technical problems - AP view may cause cardiac magnification as demonstrated in this comparison |
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lateral view |
- the left hemi-diaphragm is usually lower than the right - also, since the heart lies prdominately on the left side the result on a lateral film is sihouetting |
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cxr technique |
- the diaphragm should be found at about the level of the 8th - 10th posterior rib on a good inspiration - make sure there's a good inhalation - you can tell if it's a poor inspiration if there are more than 10 ribs in the x-ray |
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rotation |
evaluate if cxr is rotated by looking at the clavicular head. If the clavicular heads are equal distance from the spinal processes then they're fine if the clavicles are rotated it's not a good flim |
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penetration |
determine how much radiation the patient was exposed to. we have no control over this. remember to check inhalation, rotation and exposure (slide 15) |
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landmarks: mediatinum |
key points you can see to navigate the film - right heart border - left heart border - diaphragm - aortic arch - hilum - make sure the bottom ribs are curved look at the vascular tissue to check the presence/progress of disease processes |
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steps to read an x-ray |
- trachea: midline or deviated? mass? - lungs: abnormal shadowing or lucency - pulmonary vessels: artery or vein enlargement - hila: masses, lymphadenopathy - heart to thorax widith greater than 2 :: 1. if heart takes up too much of the lung field then consider it too large - mediastinal contour: width? mass? - pleura: effusion, thickening, calcification - bones: lesions or fractures - diaphrams: visible, well defined think about if anything looks fractured or abdormal |
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tracheal deviation |
- this image shows a goiter that has displaced the trachea evidenced by the shift in the chracteristic air- shadow - a patient with a goiter will show tracheal deviation on an x-ray |
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sihouette sign |
- occurs with the loss of lung tissue due to mass or fluid - if you have an opacity next to the heart border then the opacity will opacity will obscure the border - you see right middle lobe consolidation sihouette sign here |
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air bronchogram |
- air bronchogram is a tubular outline of an airway made visible by filling the surrounding alveoli by fluid or inflammatory exudate - this picture shows outline of alveoli
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what are causes of air bronchograms? |
- lung consolidation - pulmonary edema - non-obstructive pulmonary disease, atelectasis - severe interstitial disease, neoplasm - normal expiration
remember not all nodules are malignant |
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nodules |
- nodules can be benign or maligant - compare old films - if borders are irregular consider further work up - if found on x-ray refer to pulmonary |
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sail sign |
- can be normal in a child as in this x-ray - outline of the thymus - in an adult maybe a sign of lung collapsed |
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metastatic disease |
- you see differentiation here - you do not see differentiation during pleural edema |
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atelectasis |
- atelectasis is collapse or incomplete expansion of the lung or part of the lung - increase in density - raised diaphgragm on the effected side (volume loss) -loss of fluid volume, diaphragm pulled up a bit |
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pulmonary edema |
- nepfilled with fluid and cannot see the heart - bat wings |
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pneumonia |
- pneumonia is airspace disease and consolidation - air spaces are filled with bacteria or other microorganisms and pus - there is no volume loss as seen in atelectasis |
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pleural effusion |
- blunting of costophrenic sulci - the fluid goes to the base of the lungs due to gravity - depression of the diaphragm may occur as seen here - approx. 200 ml of fluid are needed to detect an effusion in the frontal film vs. approx 75 ml for the lateral - larger effusions, esp if unilateral, more likely to be caused by malignancy than small ones - not a nice triangle, all fluid |
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large pleural effusion |
- fluid is fairly dense, much more dense than air - mostly on the R side chest is filled with fluid - meniscus is seen along the lateral chest wall, as indicated by the arrow |
