Radiography Outline PDF

Radiography X-Rays - X-Rays are a type of electromagnetic radiation that can pass through most objects, including the body - They are used to generate images of tissues and structures inside the body - Radiography is based on the ability of x-rays to penetrate tissues and organ...

Radiography X-Rays - X-Rays are a type of electromagnetic radiation that can pass through most objects, including the body - They are used to generate images of tissues and structures inside the body - Radiography is based on the ability of x-rays to penetrate tissues and organs differently according to tissue density\*\*\* - X-rays are generated by a machine that passes a high-voltage electrical current through a tungsten filter in a vacuum tube (x-ray tube) - Images are formed on photographic film positioned on the other side of the body - Images are produced in varying degrees of dark and light, depending on the amount of x-rays that penetrate the tissues - The greater the energy absorbed, the less x-rays reach the film and the whiter the image appears on the film\*\*\* - Radiolucent materials that allow x-rays to penetrate with a minimum of absorption - Radiopaque not permitting the passage of x-rays Basic tissue radiographic opacities +-----------------------------------+-----------------------------------+ | **Air/Gas** | - Most radiolucent material | | | visible on radiographs | | | | | | - This lucency provides | | | contrast to allow | | | visualization of various | | | structures | +===================================+===================================+ | **Fat** | - Surrounds organs and | | | structures | | | | | | - Helps to delineate them by | | | producing contrast for | | | differentiation and | | | visualization | +-----------------------------------+-----------------------------------+ | **Soft Tissue & Fluid** | - Variation in volume, | | | thickness and degree of | | | compactness of soft tissue | | | creates a pattern of various | | | densities on the radiograph | +-----------------------------------+-----------------------------------+ | **Mineral/Bone** | - Comprised mostly of calcium & | | | phosphorus | | | | | | - Normal variation of same bone | | | and between different types | | | of bone | | | | | | - Diseased bone may be less | | | opaque | +-----------------------------------+-----------------------------------+ | **Metal** | - Most opaque shadow seen on | | | radiographs | | | | | | - May be seen as contrast | | | media, orthopedic implants, | | | or metallic foreign bodies | +-----------------------------------+-----------------------------------+ Standard X-ray Views: - Anteroposterior (AP): - X-rays pass through the front of the body (anterior) to the back (posterior) - Posteroanterior (PA): - X-rays pass through the back of the body to the front - Lateral - X-rays pass straight from the side of the patient to the other side - Oblique - X-rays pass through the body while the pt is angled b/w AP and PA position - More specific views: cervical spine, foot, hand The risk for developing cancer from medical imaging radiation exposure is generally very small, and it depends on: - Radiation dose - The lifetime risk of cancer increases the larger the dose and the more X-ray exams a pt undergoes - Patients age - The lifetime risk for cancer is larger for a pt who received x-rays at a younger age than one who received them at an older age - Patients sex - Women are at somewhat higher lifetime risk than men for developing radiation-associated cancer after receiving the same exposures at the same ages - Body region - Some organs are more radiosensitive than others Principles of Radiation Protection - Justification - Imaging procedures should be judged to do more good than harm to the individual pt. - All exams using radiation should be performed **only when necessary.** - The clinical indication and patient medical history should be carefully considered before referring a patient for any X-ray exam. - Optimization - As Low As Reasonably Achievable (ALARA), principle of radioprotection states that whenever ionizing radiation has to be applied, exposure should be as low as reasonably achievable.\*\*\* - The technique factors used should be chosen based on the clinical indication, patient size, and anatomical area scanned; and the equipment should be properly maintained and tested. 3 types of damage to the body from Radiographic procedures: - Somatic - Occur in patients exposed to the harmful agent, these may include short-term effects such as blood cell problems or long-term effects such as cancer - Genetic - Include damage to future generations as a result of exposure of parent germ cells to a harmful agent. - Genetic effects can range from mild to severe - Fatal - Occur as result of exposure to harmful agent during embryonal or fetal state of development. - Highly dependent on timing of exposure with respect to gestational age. - Damage ranges from mild birth defects to childhood malignancies. Greatest risk is early pregnancy when organs developing Interfering Factors: - Metallic objects - Barium retained from previous procedures - Large amounts of fecal matter or gas in the bowel - Improper positioning - Excessive movement Confirm details - Although mistakes are rare, they do occur and you should verify details pertaining to your patient on every study you review - Patient: - Ensure the study was performed on the correct patient. - Joint Commission recommends 2 pt identifiers (name, DOB, medical record number) - Time and date -- Note the time and date of the study.  - This is especially important if there are comparison studies.  - The older study is usually displayed on the left. - X-Ray Identifiers: - Study type - Verify AP vs PA - Position of Pt- supine, standing, sitting - Label correct sides- Right vs Left - Comparisons -- - Make sure you view every image submitted. - It is not uncommon for multiple views to be taken for an AP supine CXR study on a difficult to position patient.   - Compare these to previous studies, if available Chest X-Rays Chest X-Ray Reasoning - Assess injuries from an accident - Monitor progression of a disease (cystic fibrosis) - To evaluate lung symptoms such as cough, fever, and shortness of breath (PNA, pneumothorax) - To screen for other diseases (TB, Cancer) - To evaluate heart symptoms such as chest pain, edema, and shortness of breath - To assess if implanted devices are in place Views: - Standard views - Posteroanterior (PA)- This reduces the magnification of the heart and other anterior mediastinal structures that are situated close to the film in the PA position.  - Lateral- Left side up to plate - Portable/Mobile views - Anterior to Posterior (AP)- In the ICU and ER, CXRs are often taken with the film placed behind the patient and the x-ray tube in front of the patient because the patient is bed bound or unstable and thus lying down (supine), or barely sitting up (semi-erect). Quality: "RIPE" - Rotation - A critical factor in the acquisition of a good-quality frontal radiograph of the chest is the patient\'s orientation with respect to the film or---in this age of digital images---with respect to the cathode ray (CR) device. - Good-quality chest radiographs are described as truly \"straight.\" - To acquire a straight film, the pt must be exactly perpendicular to the x-ray beam. - Any degree of deviation from the perpendicular will result in a rotated film. - In a radiograph in which the patient is rotated right posterior oblique, the medial aspect of the clavicle on the left will appear closer to the spinous process of the thorax than will that of the contralateral side. The opposite is also true. - The degree of rotation can have a profound effect on the radiographic appearance of a normal chest. - On a rotated film, the mediastinal and hilar regions can appear markedly different than they would on a straight film. - This altered appearance could potentially lead one to incorrectly suspect a mediastinal mass or other abnormality. - Inspiration - If the patient\'s inspiratory result when the film was obtained was suboptimal, then the vascular structures may appear crowded and indistinct, giving an appearance that can mimic congestive heart failure. - The cardiac silhouette may also appear falsely enlarged. - Deeper inspirations show more lung and result in better overall images with less haziness at the lung bases and less enlargement of the heart and mediastinum.  - The diaphragm should be found at about the level of the 8^th^-10^th^ posterior rib or 5^th^-6^th^ anterior rib on good inspiration. - Position - A supine radiograph or semi-erect film looks different from an upright radiograph. - The best way to assess patient position is to search the image for gas-fluid levels. - These are most commonly seen in the gastric fundus. - If one is visible, you can be sure the image was obtained with the patient upright. - If pt\'s position in film is incorrectly identified, the appearance of the pulmonary vasculature may be misinterpreted. - In upright position, gravity causes the flow of blood in the lungs to go to lower lobes. - When pulmonary venous pressure increases (precursor to CHF), upper lobe vessels become larger and resemble those in the lower lobe.  - Exposure - Exposure refers to the amount of x-ray energy that passes through the patient during the acquisition of the image.  - A good radiograph should demonstrate adequate penetration of the patient and sufficient contrast to distinguish between adjacent structures of different densities. Exposure is best assessed by trying to visualize the intervertebral disks in the lower thoracic spine through the heart. - Normal anatomy is not well visualized on either overexposed or underexposed radiographs. In addition, certain abnormalities, such as a small nodule in the lung, may not be visible on an overexposed film; others, such as a small lucency of bone suggest-ing a focal cancerous metastasis, may not be visible on an underexposed film. ABCDEFGH Pneumonic for X-ray Interpretation - Airway - The airway, or trachea, should be midline without any deviation or stenosis after taking into account any rotational variations. - Bones and Soft tissue - Check the bones both in and out of the chest cavity for fractures, lytic lesions (darkened areas), and deformities. Examine the joint spaces for widening or narrowing. - Cardiac - Normal heart size is half the chest width. Examine the shape of the heart. A water-bottle-shaped heart can be indicative of pericardial effusion. The borders around the heart should be clear. - Diaphragm - Evaluation of the diaphragm should reveal clear margins and sharp costophrenic angles bilaterally. When the diaphragmatic border is obscured, it indicates an adjacent disease process. - Effusion and extra thoracic tissues - Assess the pleura to ensure full expansion. - Examine the soft tissues for abnormalities, specifically lymph nodes and subcutaneous emphysema (air below the skin), as well as any other lesions. - Fields/fissures/foreign bodies - Divide the lungs into sections and look for symmetry between the lungs. - Check for consolidation and fluid. - Foreign bodies are generally supportive hardware such as chest tubes, central lines, endo-tracheal tubes, pacemakers, etc. - Great vessels and gastric bubble - Aorta, Pulmonary Arteries, & Superior Vena Cava. - Below the left hemidiaphragm you should notice a gastric bubble (from the stomach). - There should be no other free air below the diaphragm. - Hila and mediastinum - The hila are not symmetrical but contain the same basic structures on each side. - The hila may be at the same level, but commonly the left hilum is higher than the right. - Both hila should be of similar size and density. - If either hilum is bigger and more dense, this is a good indication that there is an abnormality. Terminology - Consolidation - If alveoli and small airways fill with dense material, lung is said to be consolidated. - May fill with pus in pneumonia, fluid in pulmonary edema, blood in pulmonary hemorrhage, or cells in cancer. - Opacities - Capacity of a substance to absorb radiation, rather than permit its passage. - If there is an opacity in the lung where there should be translucency you need to ask what is causing it. - Mass/Nodules - Small round or oval-shaped growth in the lung. - Pulmonary nodules are \< 3 centimeters in diameter. - If the growth is larger than that, it is called a pulmonary mass and is more likely to represent a cancer than a nodule. - Atelectasis - Collapse of lung tissue with loss of volume - Fibrosis - Scarring in the lung tissue - Pleural effusion - Collection of fluid abnormally present in the pleural space, usually resulting from excess fluid production and/or decreased lymphatic absorption - Pneumothorax - Presence of air of gas in the pleural cavity which can impar oxygenation and/or ventilation (AKA lung collapse) - Hemothorax - Accumulation of blood and fluid in the pleural cavity, between the parietal and visceral pleura - Cardiomegaly - Enlargement of the heart RIB Fractures Rib fracture identification - Rib fracture is the most common thoracic injury and is present in 10% of all traumatic injuries and in almost 40% of patients who sustain severe nonpenetrating trauma - Rib fractures typically affect the fifth through ninth ribs. - This may be due to the fact that the shoulder girdle affords relative protection to the upper ribs, and the lower ribs are relatively mobile and may deflect before fracturing Etiologies of rib fx: - Rib fx can occur without direct trauma such as chronic or hard coughing or sneezing - Rib fractures also occur during participation in various sports such as rowing and golf, often elite athletes - Can also be a result of various diseases such as cancer or infections - When isolated, rib fx have a relatively low morbidity and mortality - When rib fractures are more severe their associates complications can produce significant morbidity Rib fracture complications - Pneumothorax - Hemothorax - Pulmonary contusion - Pneumonia and atelectasis - Flail chest - Cardiovascular injury - Nerve and blood vessel injury - Injuries to solid and hollow abdominal organs Note: May not always be able to see a rib fx important to control pain, prevent PNA, ensure rib is not displaced Rib views: - Chest X-ray and rib series are commonly used and accepted - They are specific but not sensitive and commonly miss rib fractures - A rib series consists of a marker placed over the region of interest, oblique views, and optimization of the radiograph by the technician to highlight bony detail, guiding clinical judgment on rib radiography. Interpretation of chest X-ray: - Tracheal deviation is d/t unequal intrathoracic pressure +-----------------------------------+-----------------------------------+ | **Abnormalities deviating trachea | **Abnormalities deviating trachea | | away from affected side** | toward affected side** | +===================================+===================================+ | Pneumothorax | Marked atelectasis / collapse | | | lung | | Pleural effusion | | | | Lobectomy / pneumonectomy | | Large mass | | | | Pleural fibrosis | | | | | | Pulmonary fibrosis (rarely | | | unilateral) | +-----------------------------------+-----------------------------------+ CXR quality tutorial CXR anatomy tutorial CXR systematic approach tutorial RIB tutorial Only page 7 Page 11 Need to know: L atrial enlargement -- splaying of the carinal angle \>90 OR double density sign Right ventricular enlargement -- filling of retrosternal space (on lateral view) caused by pulm HTN, and pulm valve disease Small effusions will be seen on the lateral view prior to PA view -- if seen on the PA, its larger Water bottle signs, oreo cookie sign When looking at the hila -- looking at different density and asymmetry (density and size)