3Standard Positions and Techniques of Chest Radiography Posteroanterior (PA) radiographAnteroposterior (AP) radiographLateral radiographLateral decubitus radiograph
4Posteroanterior Radiograph The standard PA chest radiograph is obtained by having the patient stand (or sit) in the upright position.The anterior aspect of the patient’s chest is pressed against a film cassette holder.
5Figure 7-1. Standard PA chest radiograph with the patient’s lungs in full inspiration.
6Figure 7-2. A PA chest radiograph of the same patient shown in Figure 7-1 during expiration.
7Figure 7-3. Compared with the PA chest radiograph, the heart is significantly magnified in the AP chest radiograph. In the PA radiograph the ratio of the width of the heart to the thorax is normally less than 1 : 2.
8Anteroposterior Radiograph The supine AP radiograph may be taken in patients who are debilitated, immobilized, or too young to tolerate the PA procedure.The AP radiograph is usually taken with a portable x-ray machine at the patient’s bedside.The film is placed behind the patient’s back, with the x-ray machine positioned in front of the patient approximately 48 inches from the film.
9Figure 7-4. AP chest radiograph. The diaphragms are elevated, the lower lung lobes appear hazy, the ratio of the width of the heart to the thorax is greater than 2 : 1, and extraneous lines are apparent on the patient’s left side.
10Lateral RadiographThe lateral radiograph is obtained to complement the PA radiograph. It is taken with the side of the patient’s chest compressed against the cassette.The patient’s arms are raised, with the forearms resting on the head.
12Lateral Decubitus Radiograph The lateral decubitus radiograph is obtained by having the patient lie on the left or right side rather than standing or sitting in the upright position.The naming of the decubitus radiograph is determined by the side on which the patient lies.Thus a right lateral decubitus radiograph means that the patient’s right side is down.
13Figure 7-6. Subpulmonic pleural effusion. Right lateral decubitus view Figure 7-6. Subpulmonic pleural effusion. Right lateral decubitus view. Subdiaphragmatic fluid has run up the lateral chest wall, producing a band of soft tissue density. The medial curvilinear shadow (arrows) indicates fluid in the lips of the major fissure.
15Figure 7-7. Normal PA chest radiograph. 1, Trachea (note vertebral column in middle of trachea); 2, carina; 3, right main stem bronchus; 4, left main stem bronchus; 5, right atrium; 6, left ventricle; 7, hilar vasculature; 8, aortic knob; 9, diaphragm; 10, costophrenic angles; 11, breast shadows; 12, gastric air bubble; 13, clavicle; 14, rib.
16Figure 7-8. Normal lateral chest radiograph. 1, Manubrium; 2, sternum; 3, cardiac shadow; 4, retrosternal air space in the lung; 5, trachea; 6, bronchus, on end; 7, aortic arch (ascending and descending); 8, scapulae; 9, vertebral column; 10, diaphragm; 11, breast shadow.
17Table 7-1 Common Radiologic Terms Air cystBlebBullaBronchogramCavityConsolidationHomogeneous densityHoneycombingInfiltrate
20Lung abscess with cavities CavityLung abscess with cavitiesRadiograph of cavityReactivation tuberculosis (TB) with a large cavitary lesion containing an air-fluid level in the right lower lobe.Lung abscess with air-fluid cavity.
21Cavity (Cont’d) Lung with TB cavities Radiograph of cavity Tuberculosis.Cavitary reactivation TB showing a left upper lobe cavity and localized pleural thickening (arrows).
22Consolidation or Opacity (Caused by Right Lung Pneumonia)
30Translucency or Radiolucency (Caused by a Right Pneumothorax)
31Translucency or Radiolucency Caused by Chronic Emphysema Centrilobular emphysema.Chest x-ray study of a patient with emphysema.
32Technical Quality of the Radiograph Exposure qualityLevel of inspiration
33First Technical Quality Was the patient in the correct position?Check the medial ends of the clavicles to the vertebral column.Even a small degree of patient rotation can create a false image.Can erroneously suggest tracheal deviation, cardiac displacement, or cardiac enlargement
34Second Exposure Quality Normal exposure is verified by determining whether the spinal processes of the vertebrae are visible to the fifth or sixth thoracic level.Compare the relative densities of the heart and lungs.Overexposure: heart and lungs more radiolucentUnderexposure: heart and lungs more dense or whiter
35Third Level of Inspiration When Radiograph Was Taken At full inspiration, the diaphragmatic domes should be at the level of the ninth to eleventh ribs posteriorly.At expiration, the lungs appear denser, the diaphragm is elevated, and the heart appears wider and enlarged.
36Sequence of Examination MediastinumTracheaHeartHilar regionLung parenchyma (tissue)
37Figure 7-7. Normal PA chest radiograph Figure 7-7. Normal PA chest radiograph. 1, Trachea (note vertebral column in middle of trachea); 2, carina; 3, right main stem bronchus; 4, left main stem bronchus; 5, right atrium; 6, left ventricle; 7, hilar vasculature; 8, aortic knob; 9, diaphragm; 10, costophrenic angles; 11, breast shadows; 12, gastric air bubble; 13, clavicle; 14, rib.
38Sequence of Examination (Cont’d) PleuraDiaphragmGastric air bubbleBony thoraxExtrathoracic soft tissues
39Figure 7-7. Normal PA chest radiograph Figure 7-7. Normal PA chest radiograph. 1, Trachea (note vertebral column in middle of trachea); 2, carina; 3, right main stem bronchus; 4, left main stem bronchus; 5, right atrium; 6, left ventricle; 7, hilar vasculature; 8, aortic knob; 9, diaphragm; 10, costophrenic angles; 11, breast shadows; 12, gastric air bubble; 13, clavicle; 14, rib.
40Structure Abnormal Position Causes Table 7-2 Examples of Factors That Pull or Push Anatomic Structures out of Their Normal Position in the Chest RadiographStructureMediastinumTracheaCarinaHeartMajor vesselsAbnormal PositionLeftward shiftCausesPulled left by upper lobe tuberculosis, atelectasis, or fibrosisPushed left by right upper lobe emphysematous bulla, fluid, gas, or tumor
41Structure Abnormal Position Causes Table 7-2 Examples of Factors That Pull or Push Anatomic Structures out of Their Normal Position in the Chest Radiograph (Cont’d)StructureLeft diaphragmAbnormal PositionUpward shiftCausesPulled up by left lower lobe atelectasis or fibrosisPushed up by distended gastric air bubble
42Structure Abnormal Position Causes Table 7-2 Examples of Factors That Pull or Push Anatomic Structures out of Their Normal Position in the Chest Radiograph (Cont’d)StructureHorizontal fissureRight lungRight hilumAbnormal PositionDownward shiftCausesPulled down by right middle lobe or right lower lobe atelectasisPushed down by right upper lobe neoplasm
43Structure Abnormal Position Causes Table 7-2 Examples of Factors That Pull or Push Anatomic Structures out of Their Normal Position in the Chest Radiograph (Cont’d)StructureLeft lungAbnormal PositionRightward shiftCausesPulled right by right lung collapse, atelectasis, or fibrosisPushed right by left-sided tension pneumothorax or hemothorax
45Computed TomographyComputed tomography (CT) scanning provides a series of cross-sectional (transverse) pictures of the structures within the body at numerous levels.45
46Figure 7-9. The principle of spiral computed tomography Figure The principle of spiral computed tomography. The patient moves into the scanner with the x-ray tube continuously rotating and the detectors acquiring information. The rapidity of data acquisition allows a complete examination of the throax to be performed in a single breath hold.
47Normal CT Scan Lung Window Figure Overview of normal lung window CT scan. The apex appears in the two views in the upper right corner of this figure; the diaphragm at the base of the lungs appears in the lower right hand view.
48Example of Several Normal CT Scan Lung Window Slices
49Normal CT Scan Lung Window BFigure Close-up of a normal lung window CT scan. A, The portion of the chest the CT scan is taken.Figure B, The actual cross-sectional slice, or axial view of the chest.
60Example of Several Normal CT Scan Mediastinal Windows
61Figure Close-up of a normal lung window computed tomography (CT) scan. A, The portion of the chest undergoing CT scanning. B, The actual cross-sectional slice, or axial view of the chest. Note the carina and both mainstem bronchi (arrow)61
62Normal CT Mediastinal Window Figure Close-up of normal CT mediastinal window. A, The portion of the chest the CT scan is taken. B, The actual cross-sectional slice, or axial view of the chest. Note that the lungs are overexposed and appear mostly black. The bone and mediastinal organs appear mostly white.
73Positron Emission Tomography (PET) Scan The PET scan shows both the anatomic structures and the metabolic activity of the tissues and organs scanned.
74ABFigure Chest radiograph identifying two suspicious findings: in the right upper lobe (A) and in the left lower lobe (B), just behind the heart (white arrows).
75CT scan, upper right lobe Chest radiographCT scan, left lower lobeFigure Same chest radiograph as shown in Figure Note that the CT scan also identifies the suspicious nodules and their precise location.
76Coronal ViewFigure PET scan: coronal views. The last three views show a hot spot in the left lower lobe.
77Figure 7-16. PET scan: sagittal views Figure PET scan: sagittal views. The encircled images show a hot spot in the lower left lobe.
78Axial ViewFigure PET scan: axial view. A “hot spot” is further confirmed in left lower lobe.
79Axial View No hot spot seen Figure PET scan: axial view. This image confirms that the small nodule identified in the upper right lobe in the chest radiograph and CT scan is benign (i.e., no hot spot is evident).
80Positron Emission Tomography and Computed Tomography Scan (PET/CT scan) The PET scan and the CT scan merge together at the same time.The PET/CT scan provides an image far superior to that afforded by either technology independently.The CT scan provides the anatomic details; the PET scan provides the metabolic activity of the tumor or mass.
81CT Scan CT/PET Fusion PET Scan Axial ViewCoronal ViewFigure CT/PET scan (center). CT scan, CT/PET fusion, and PET scan, are all showing the same malignant nodule in right upper lobe (white arrow). Note: CT/PET fusion is normally presented in color (e.g., red, blue, yellow).
82Magnetic Resonance Imaging (MRI) MRI uses magnetic resonance as its source of energy to take cross-sectional (transverse, sagittal, or coronal) images of the body.
83Figure Anatomy of mediastinum on magnetic resonance imaging (MRI) scan. A, Ao A, Aortic arch; Es, esophagus; LBCV, left brachiocephalic vein; RBCV, right brachiocephalic vein; T, trachea. B, Az V, Azygos vein; D Ao, descending aorta; Es, esophagus; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle. (From Armstrong P, Wilson AG, Dee P: Imaging of diseases of the chest, St Louis, 1990, Mosby.)
84Pulmonary Angiography Pulmonary angiography is useful in identifying pulmonary emboli or arteriovenous malformation.It involves the injection of a radiopaque contrast medium through a catheter that has been passed through the right side of the heart and into the pulmonary artery.
85Figure Abnormal pulmonary angiogram. Radiopaque material injected into the blood is prevented from flowing into the left lung past the pulmonary embolism (arrow). No vascular structures are seen distal to the obstruction.
86Ventilation-Perfusion Scan A ventilation-perfusion scan is useful in determining the presence of pulmonary embolism.The perfusion scan is obtained by injecting small particles of albumin, called macroaggregates.Tagged with a radioactive material such as iodine- 131 or technetium-99m
87Figure Fat embolism in a patient with dyspnea and hypoxemia after a recent orthopedic procedure. Perfusion (P) and ventilation (V) radionuclide scans show multiple peripheral subsegmental perfusion defects suggestive of fat embolism. (From Hansell DM, Armstrong P, Lynch DA, McAdams HP: Imaging of diseases of the chest, ed 4, Philadelphia, 2005, Elsevier.)
88FluoroscopyFluoroscopy is a technique by which x-ray motion pictures of the chest are taken.Fluoroscopy subjects the patient to a larger dose of x-rays than does standard radiography.Therefore it is used only in selected cases, as in the assessment of abnormal diaphragmatic movement.
89BronchographyBronchography entails the instillation of a radiopaque material into the lumen of the tracheobronchial tree.A chest radiograph is then taken, providing a film called a bronchogram.The contrast material provides a clear outline of the trachea, carina, right and left main stem bronchi, and segmental bronchi.
90Figure Bronchogram obtained using contrast medium in a patient with a history of bronchiectasis. Arrows indicate the carina and the bronchi leading to the posterior basilar segment of the left lower lobe.