Week 12 RCP CXR.pdf

Week 12 Cardiopulmonary Imaging: Chest Xray Cardiopulmonary imaging Ri Imaging studies are important part of diagnosing patients with cardiopulmonary disease. RCP’s should be able to evaluate and understand th...

Week 12 Cardiopulmonary Imaging: Chest Xray Cardiopulmonary imaging Ri Imaging studies are important part of diagnosing patients with cardiopulmonary disease. RCP’s should be able to evaluate and understand these images to better treat and understand these imagies to better treat and understand their patient's diagnosis. Chest radiographs are very popular, inexpensive and reliable in most cases. Terminology - Radiolucent: Dark pattern, air (Normal) - Radiodense/opacity - radiopaque: White pattern, solid, fluid (normal for bones and organs) Things can cause: fluid, mass, bones, dense liquid (pneumonia) - Infiltrate: ill-defined radiodensity (atelectasis) Plate-like - Consolidation: Solid white area (pneumonia or pleural effusion - fluid inside the pleural space, excessive quantity) - Hyperlucency: Extra pulmonary air; COPD, asthma exacerbation, pneumothorax - extra air inside the pleural space: adding O2 to their regimens if not responding, consider a LVN (cont. albuterol treatment), antileukotrienes, systemic steroids: Magnesium, cont. albuterol. - Vascular markings: Lymphatics, vessels, lung tissue (increased with CHF, absent with pneumo) Spread throughout the lungs - Diffuse: spread throughout (atelectasis, pneumonia) - Opaque: Fluid, solid (consolidation) - Bilateral: Both sides - Unilateral: One side - Fluffy infiltrates: Diffuse (spread throughout) whiteness, butterfly/batwing pattern = pulmonary edema. - Patchy infiltrates: scattered densities (atelectasis) more severe - Platelike infiltrates: thin-layered densities (atelectasis) - Ground glass, honeycomb: reticulogranular uniformly distributed through both lung fields (ARDS, fibrosis) Various radiographic positions A). Posteroanterior (most common and ideal: Passing from the back (posterior) to the front with image receptor positioned in front of the patient. B). Lateral: Abbv. “Lat” Taken as an orthogonal view to a frontal. C). Right Anterior Oblique: The patient should be rotated 45 degrees towards the right side, with the right side of the chest against the image receptor. D). Anteroposterior: from Anterior to Posterior - Front to back E). Anteroposterior Supine: The patient lies flat on their back, xray front to back with detector placed underneath, patient on top. F). Right lateral Decubitus: Patient lying on their right side with the body’s longitudinal axis perpendicular to the imaging table. Week 12 Cardiopulmonary Imaging: Chest Xray *The heart should be Less than half the diameter of the chest in the X-ray image. If it’s greater than half the diameter = Cardiomegaly, potential heart failure due to a lot of fluid inside it. It becomes larger. Different densities Air: Black because it absorbs x rays the least and result in dark shadow (radiolucent) Bone: Absorb most xray energy and result in white shadow (radiopaque) Fat/soft tissue/fluid: Varying degrees of gray PA Chest film PA chest film is created in radiology department usually with patient standing X Ray beam passes from posterior to anterior (PA) with film places against patient’s chest Usually results in high quality film with minimal magnification of heart shadow. AP Chest Film = heart will appear larger Taken with portable x-ray machine X-ray is in front patient & film is behind patient AP films are often more difficult to read because quality is not as good as PA film Heart shadow is more magnified with AP film since heart is closer to x ray source and farther from the film. Rotation of patients is more likely. Technical factors In supine (Laying flat on your back) position the diaphragm is elevated. On an AP film heart appears larger because it is more anterior Penetration refers to the amount of x ray exposure Overpenetrated film will appear too black Underpenetrated film will appear too white. Indications for a CXR - Unexplained dyspnea - Severe persistent cough - Hemoptysis - Fever and sputum production - Acute severe chest pain - Fever and sputum production - Acute severe chest pain - Positive TB skin test - ETT placement: endotracheal tube - do x ray after the placement. It is essential.All ages. - Placement of pulmonary artery catheter, central venous pressure catheter - Elevated or changing plateau pressure during mechanical ventilation - Sudden decline in oxygenation - Consolidation = Pneumonia Week 12 Cardiopulmonary Imaging: Chest Xray Approach to reading chest film - Disciplined approach is needed - Don’t immediately look at what is obvious. Less obvious items can be just as important. - First: Make sure the name on film matches patient being evaluated - Second: Evaluate technical quality of film (proper patient position, xray penetration, etc) - Third: Systematically evaluate all anatomical structures seen on film following prescribed series of steps. Other important factors to note - In Pulmonary embolism may appear normal in x ray - Chronic COPD patients may also appear normal - There may be a lag time behind clinical condition of the patient: - Ex: Aspiration pneumonia, fever with cough (can take 12-24 hours to show) Assessment A = Airways (trachea, is it midline? Center, is it shifting? Very high concern) B = Bones and soft tissues (Vertebral bodies, spinal process) C = Cardiac Silhoutte & Mediastinum (Enlarged, deviated) D = Diagphram (gastric bubble, flattening, Right slightly higher than left because of liver) E = Effusion (Pleura), Lateral decub to R/O effusion F = Fields, Lung fields Lines, tubes, previous surgeries Should be taken on full inspiration otherwise it may make the heart appear larger and airway with volume loss. Assessment of structures Chest wall and Mediastinum Symmetry of Chest (Does it look equal on both size) Rib fractures Bone changes Heart size Presence of free air or fluid Lung evaluation Size, density and symmetry Lung edges in frontal and lateral films Vascular markings Presence of free air or fluid Consolidation and infiltrates In pneumothorax the trachea will shift away from the infected lungs. Hydrothorax / Pleural Effusions Week 12 Cardiopulmonary Imaging: Chest Xray - More commonly called a Pleural effusion - Blunted costophrenic angle on chest x-ray indicates pleural effusion is present - About 200 ml of pleural fluid will blunt costophrenic angle - Best chest xray view for detecting small pleural effusion is lateral decubitus - Pus in pleural space = empyema (pus filled pockets that develop in the pleural space) Diaphragm should be dome shaped Diaphragm flat = increase presence of air Pneumothorax - Refers to collection of air in pleural space -. May occur spontaneously with trauma or with invasive procedure. - May occur with mechanical ventilation called barotrauma in such cases. - Pneumothorax causes lung margin to pull away. - Presence of air can be better visualized by comparing inspiratory vs expiratory, Tension Pneumothorax - Represents serious medical emergency - Occurs when air within pleural space is under pressure - Air accumulates in pleural space on inspiration but cannot exit on exhalation - Chest film will show shift of mediastinum away from pneumothorax - Requires immediate decompression with chest tube or needle aspiration of trapped air. - Can lead to cardiac tamponade and hemodynamic collapse Pigtail catheter Pulmonary infiltrates = pus or fluid inside the lungs Fluid = Pulmonary edema Pus = Pneumonia - Seen on chest radiograph when alveoli fill with watery fluid (edema), pus (pneumonia), blood (alveolar hemorrhage), blood alveolar (alveolar hemorrhage) or fat rich material (alveolar proteinosis) - Seen as white shadows in lung - Air bronchogram refers to the phenomenon of air bronchi (dark) being made visible by opacification of surrounding alveoli (gray/white) Pulmonary Edema P.E due to left heart failure is common on chest radiograph Left heart failure causes enlargement of pulmonary blood vessels in apex of lung (cephalization: If blood vessels to the apices of the lungs are the same size or larger than the blood vessels to the bases. Kerley B-lines are often seen with pulmonary edema due to left heart failure Chest radiograph often shows enlarged heart and pleural effusion with CHF Week 12 Cardiopulmonary Imaging: Chest Xray Interstitial disease Chest radiograph usually Shows diffuse, bilateral infiltrates. Infiltrates may look like scattered ill-defined nodules. Many different types of ILDs; 2 most common: Idiopathic pulmonary fibrosis, sarcoidosis ”Honeycomb” appearance can occur with idiopathic pulmonary fibrosis, collargen vascular disease, asbestosis, chronic hypersensitivity pneumonitis, medication induced (amiodarone) ARDS: Ground glass appearance, Honeycomb pattern, Diffuse bilateral radiopathy. Atelactasis = Defined as collapsed or airless condition of the lung Common finding on chest radiograph, especially in postoperative patient When localized to subsegmental portion of lung - called “plate atelectasis” Lobar atelectasis osccurs when major bronchus is obstructed by mucus plug, tumor, or foreign body. Signs of volume loss = elevation of hemidiaphragm and shift of helium towards affected side Transcription may read “infiltrate” which describes an ill defined radiodensity. Hyperinflation Commonly seen with emphysema Other signs of hyperinflation include: - Flattening of hemidiaphragms - Large retrostrenal airspace - Narrowed Mediastinum - Increased AP diameter Emphysema causes loss of visible blood vessels in lung Thumb sign = Epiglottitis (Lateral neck image) Steeple sign = Croup Catheters, Lines, Tubes Chest radiograph is obtained after placement of endotracheal tube, CVP line or pulmonary artery catheter Film helps confirm tube or catheter is in correct position Tip of the endotracheal tube should be 2-6 cm above the carina with the patient's head in neutral position. Below the vocal cords. At the level of the aortic knob or notch, below the clavicles. Pacemaker should be positioned in the right ventricle. Pulmonary artery catheter in the right lower lung field Chest tubes in the pleural space surrounding the lungs Nasogastric tubes and feeding tubes should be positioned in the stomach 2-6 cm below the diaphragm. Week 12 Cardiopulmonary Imaging: Chest Xray Cat Scan Computed tomography (CT) is very helpful in certain situations CT visualizes structures cross-sectionally with great detail up to 2 mm structures inside the lung. CT scanning creates images looking like “slices” of patient’s chest (5-7 mm thick) Coventional CT scanning is used to evaluate lung nodules & masses, great vessels, mediastinum and pleural disease. Iodinated contrast is sometimes used to make the blood appear more dense and allows blood vessels to be distinguished from soft tissue structure (Dye’s can cause fatal response) High Resolution CAT scan High-resolution CT (HRCT) scanning examines 1-mm slices of lung, producing greater lung detail. High-resolution CT scanning is ideal for evaluating diffuse parenchymal lung diseases; - Interstitial lung disease - Emphysema - Bronchiectasis CT is the gold standard for diagnosing pulmonary embolism. If a patient is suspected to have PE then a CAT scan will be ordered. Another one will be a stroke. Magnetic resonance imaging = to confirm brain dead Uses radio waves from realigning hydrogen nuclei to generate MRI image (no x-rays are used) Most ofter used to image mediastinum, hilar regions, and large vessels in lung. MRI has limitations in chest medicine: Cannot be used in patients with pacemaker, tracheostomy tube safety, Metal objects cannot be used near MRI machines. Ultrasound Images created by passing high frequency sound waves into the body and detecting sound waves that bounce back (echo) from tissues of the body. Ultrasonic evaluation of the lung can be performed but is limited. Uses very portable equipment: Commonly used to guide placement of central and arterial catheters and to detect and quantify pleural effusions. Very common in an emergency setting or the ICU = during codes, they wanna see if the heart if its squeezing. Ventilation Perfusion Scan (V/Q) Beneficial for identifying PE. For perfusion part - radioactive particles are injected into a vein such as albumin tagged with radioactive iodine The particles are large and cannot get through the lung capillaries and get trapped Areas of high flow will have few particles and appear “cold” or clear on the film. For the ventilation part-A radioactive gas (xenon) is inha