AP Projection. Usually in the setting of an ICU where a Portable machine is being used.A Number of factors conspire to make the Pseudo-Cardiomegaly: 1. AP Projection 2. Short FFD 3 Supine position 4. Poor Inspiratory Effort 5. Rotation 6. Lordotic position
Expiration study: Helps visualise small pneumothorax, air trapping Dz (emphysema), bronchial obstruction
False enlargement of the Heart : 1. Short FFD 2. Expiration 3. AP Projection 4. When diaphragms are elevated.5.Patient rotated to the left, 6. Lordotic position. Key = FFD: Film Focus Distance, Usually 6 feet in Chest Radiographs
The normal pleural space may contain about 5ml of fluid according to some references; about 300ml of fluid is said to be needed for it to be detectable clinically. When a pleural effusion causes only blunting of the costophrenic angle in a chest x-ray, one can assume that there is about 100 to 150ml of fluid there. 75ml is needed to blunt the posterior costophrenic angle.
If spinous process appears closer to the left clavicle (in the above slide the dark green arrow in the left), the patient is rotated toward his own right side
If there is significant rotation, the side that has been lifted appears narrower and denser (whiter) and the cardiac silhouette appears more in the opposite lung field.
C wayang kulit
CHEST RADIOGRAPHS, IMAGE QUALITY OF THE CHEST RADIOGRAPHA WAYANG KULIT Dr Ng Kian SengPart Three MBBS (Singapore) MCGP (Malaysia) Master Of Medicine (Internal Medicine, Singapore)Second Edition FAFP (Malaysia) Cert In Occupational MedicineFebruary 2012 Ph D (Theology, USA)
IMAGE QUALITY OFTHE CHEST RADIOGRAPH To assess the quality of the image of the Chest Radiograph, you have to scrutinize the CXR in the following areas: I. Inclusion P. Projection I. Inspiration E. Exposure R. Rotation. These areas are circled in Green In the next slide, “I PIER at A to J” (i.e. I peer at A to J of the alphabet.)Before interpreting the Chest Radiograph, it is In addition to the 5 above areas,imperative that you assess the quality of the you may want to look atimage. If you skip this step, you may diagnose A1. Angulation &a “phantom” disease or you may be wrongly A2. Artifacts.reassured that all is well when in reality alife threatening condition is lurking like a ghost We will look at these 7 areas in this in the pixelated shadows of a poorly created PowerPoint…Image.
Systematic (methodical) approach to the reading of the CXR is necessary to help us avoid overlookingan abnormality. Use this simple mnemonic to help you, “I PIER at A to J” (i.e. I peer at A to J of the alphabet.) Letter Description SYSTEMATIC Letter Description A Airways READING I1 Initial Survey OF THE B Bones I2 Identity CHEST C Cardiac Silhouette RADIOGRAPH I3 Inclusion P Position D Diaphragm I Inspiration E Edges of Heart, the Surrounding E Exposure Mediastinum R Rotation F Fields Of Lungs G Gastric Bubble H Hilar Regions Hardware I In case U Forget areas J Jolting Your Patient’s Memory
I = INCLUSION (Anatomy Inclusion)I A Chest X-ray should include the entire thoracic cage. Occasionally, important anatomical structures like the first rib, lateral edges of ribs & the costophrenic angles are not visualized. First Rib Cut off Lateral edge of Ribs Not Included Costophrenic Angle Not Visualized
P P = Position PA, AP, Lateral. The Standard Position or Projection is the Erect PA The ICU patient will have a supine AP view and the image will be “fuzzier”, a first look gives you the impression that it is a poor quality image. PA View Supine AP View “Fuzzier”
P Characteristics of AP Projection of a Chest Radiograph (1)“Fuzzier” AP Projection images are of lower Quality than PA views. The image is “Fuzzier” (2) “Pseudocardiomegaly” Heart is further away from the film and therefore Magnified. (3) “Scapulae” The scapulae are not retracted laterally and they remain projected over each lung. (4) “Equalization” In the Supine AP view, there is more equalization of the pulmonary vasculature when the size of the lower lobe vessels are compared to the upper.
AP & PA Projections of the Chest RadiographP AP Projection: Heart is further away from the film and therefore Magnified
I = Inspiration. Exposure should be made on deep suspendedI inspiration. Count the visible ribs. Lung fields should extend to about 10th or 11th posterior ribs. The anterior end of approximately 6-7 ribs should be visible above the diaphragm in the mid clavicular line. 1 2 3 1 2 4 3 5 6 4 7 5 8 6 9 7 10
I The difference between an Inspiration and an Expiration Film. The one taken in Expiration looks “stunted”…(on the right). Sometimes we ask for A CXR in expiration… When?
I The Difference between Normal Expansion and Hyperexpansion Normal Expansion Hyperexpansion “Elongated”
Inadequate Inspiratory Effort, Expiration Phase, Or Shallow InspirationI will result in an image that has these characteristics… (1) “Stunted” When the exposure is not made in deep suspended inspiration, the image appears stunted. (2) “Pseudocardiomegaly” The volume of air in the hemithorax will affect the configuration & dimensions of the heart . With shallow inspiration there is a smaller volume of air in the thorax & this results in an apparently “larger heart”. (3) “Diaphragm” The raised position of the diaphragm leads to exaggeration of heart size, and obscuration of the lung bases. (4) “Vascular Pattern” The vascular pattern in the lung fields will be accentuated because the same amount of blood flow is now distributed to a EXPIRATION OR smaller volume of lung. SHALLOW INSPIRATION (5) “Crowding” Crowding of lung markings may be mistaken for air space disease
I Hyperexpansion (1) “Taller” image appears taller than usual (2) “7th Rib” More than the mandatory 7th anterior rib at the diaphragm in the Mid Clavicular Line (3) “Hemidiaphragms” are Flattened (3) “Costophrenic Angles” Apparent Blunting of Costophrenic angles (5) “C.O.L.D” Usually in the patient with Chronic Obstructive Lung Disease
E = Exposure If the film is penetrated enough, you should be ableE to make out the spinous processes “inside” the vertebra. And you should be able to see the lower thoracic vertebral bodies through the heart. Correct Exposure or Penetration
E If the Film is Under Exposed, it will look “Too White”… (1) “Too White” Image is “Too White” (2) “Vertebrae” The spinous processes in the vertebrae are not visualized. Lower thoracic vertebra are not seen through the heart (3) “Lower Zones” There is poor Visibility of the lower zone structures, retrocardiac region, lower lung fields & left hemidiaphragm. (4) “Pulmonary Markings” The pulmonary markings will appear more prominent than they actually are and can simulate pneumonia or effusion Under Exposed, Film is “Too White”
E If the Film is Over Exposed, it will look “Too Black”… (1) “Too Black” Image appears “Too Black” (2) “Bones” Bony details of ribs are not visualized. (3) “Lungs” Lung markings are Not visualized. (4) “Pitfall” Over penetration results in loss of visibility of low density lesions, such as an early consolidation, a coin lesion, an early malignancy Over Exposed, “Too Black”
R = Rotation Be careful to Xray the patient “ flat “against the cassette,R if there is rotation, the mediastinum will look unusual. Look for rotation by observing the clavicle heads and determine if they are equidistant from the spinous process of the thoracic vertebra. If they are not, there is rotation.
ROTATIONR If spinous process appears closer to the right clavicle (red arrow), the patient is rotated toward his own left side . If spinous process appears closer to the left clavicle (red arrow), the patient is rotated toward his own right side
R Rotation Causes Distortion Of The Mediastinal Anatomy Green arrowsPoint to medial Heads Of clavicleYellow point to Distorted Mediastinum If there is significant rotation, the side that has been lifted appears narrower and denser (whiter) and the cardiac silhouette appears more in the opposite lung field.
R Rotation Causes These Aberrations (1) “Distortion” Rotation of the patient distorts mediastinal anatomy and makes assessment of cardiac chambers and the hilar structures difficult. (2) “Deviation” It may be difficult to know if the trachea is deviated to one side by a disease process. (3) “Transradiant” The “darker” lung field is the side nearer to the film. (4) “Magnification” Severe rotation may make the pulmonary arteries appear larger on the side farther from the film. (3) “Asymmetry” Changes in lung density due to asymmetry of overlying soft-tissue may be incorrectly interpreted as lung disease.
R THE HEART SIZE IN ROATATION Well centred patient An accurate assessment can be made Rotated patient Heart size is exaggerated Rotated patient The true size of the heart may be underestimated
Correct Angulation. The beam of the x-ray should be perpendicularA1 to the erect chest film, if it is, you will see the Medial end of Clavicle at the level of 3rd posterior rib. If the beam of x-ray is not perpendicular to the film, you will get a "distorted" image, perhaps Ending up with a lordotic view.
ArtifactsA2 The appearance of anatomical structures may be artifactual because of radiographic technique, patient factors, or the presence of external or internal non-anatomical objects. Artifact is often unavoidable, but some artifact can lead to misinterpretation of the image. Hair artifact At first glance the soft tissues at the base of the neck on the right look abnormal. Appearances simulate surgical emphysema. This artifact is due to hair which was draped around the patients neck. Click to see.
Summary : Image Quality of a Chest Radiograph Remember the Mnemonic for the Quality of a CXR I PIER A1A2 Inclusion : The whole thoracic Anatomy to be included. Position : Supine AP gives a Low quality “fuzzier” Image Inspiration : 6 to 7 anterior ribs intersecting the diaphragm in the mid-clavicular line Exposure : Spine visible behind the heart Rotation : Spinous processes at midpoint between medial ends of the clavicles Angulation : Medial end of Clavicle at the level of 3rd posterior rib Artifacts : Cause difficulties In interpretation
Inclusion of WHITE BLACKWhole Thorax Exposure Rotation ERECT PA SUPINE AP Projection Angulation IMAGEExp HyperexpInspiratory ArtifactsEffort
Collage, Shanghai Girl Series By Ng Kian SengCopyright : Please Do Not Post This PowerPoint On The Net