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Pulmonary Radiology
Rui Domingues, MDLincoln Mental and Medical Center
September 2008
Pulmonary Imaging Imaging techniques used to
investigate pulmonary pathology include:
Plain film Computed Tomography Magnetic Resonance Imaging Ultrasound Angiography
Keys to reading X-rays well
1. A good understanding of normal anatomy
2. A good search pattern
But before we can do this we need to understand how x-rays are produced.
Things to cover… Radiographic basics How to approach a chest x-ray Normal radiographic anatomy
Radiographic Basics
What causes the blacks, whites and grays of an x-ray image?
X-ray beams contains x-ray photons of differing energies
As these photons pass through a patient…
Some are absorbed completely Some penetrated directly to the plain film Some are absorbed partially, and While others are deflected (Scatter)
Tissue Density A product of the type of tissue and
the thickness of that tissue
Results in differential absorption
Differential Absorption Penetration of the x-ray beam is
dependent on tissue density
Denser object = less penetration
Less beam striking the film (more absorption) = WHITER
More beam striking the film = BLACKER
Glass Test Tube
Air
Fat
Water
Bone + Water
Metal
Differential AbsorptionBlack Air (Lungs / Trachea / Outside the body)
Fat (Perirenal fat / Fascial plane)
Water (Muscle / Organs)
Bone (Bone / Atherosclerotic plaquing)
White Metal (Fillings / Markers / Ortho devices)
Radiographic Image Adjacent structures of similar
densities are not visualized
Kidney (water density) against liver (water density)
Radiographic Image Adjacent structures of different
densities are visualized
Liver (water density) next to Bowel (air density)
Chest Films Minimum Diagnostic Series
PA Left Lateral
Additional Views Apical Lordotic Inspiration / Expiration
PA CXR Left Lateral CXR
Apical Lordotic CXR
Allows for better visualization of the Apices of the lungs
Expiration Inspiration
Visualizes respiratory excursion
Inspiration study
Normal positioning for PA Chest
Expiration study
Helps visualize: - Small Pneumothorax
- Air Trapping Dz (Emphysema)
- Bronchial obstruction
How to approach an X-ray?
Reading a Chest X-ray First thing:
Correctly put of the film
Then perform your search pattern which you always follow when looking at
any film this way you will miss fewer findings
Reading a radiograph Start reading every radiograph by
scanning the areas of least interest first, working your way to the more important areas.
You will be less likely to miss important secondary findings.
Chest Film Search Patterns ABCs
Abdomen Bone Chest Soft tissues
ATMLL Abdomen Thorax Mediastium Lung Lung
These are the two main search patterns that people use when evaluating a chest film.
“ATMLL” Search Pattern Remember
A = Abdomen T = Thorax M = Mediastinum L = Lungs (unilaterally) L = Lungs (bilaterally)
Searching the “Abdomen” Scan across the upper abdomen several
times
Evaluate normal gas containing structures: Stomach Hepatic flexure of the colon Splenic flexure of the colon
Evaluate the liver and on occasion one can visualize the spleen
Structures Visualized:
Stomach gas bubble
Splenic flexure
Liver
Hemidiaphragms
Abdomen dz that can mimic Lung disease include:
Subphrenic abscess
Diaphragmatic hernia
Hiatal Hernia
Searching the Bony “Thorax”
Start at the right base, look at the soft tissues of the chest wall, ribs, spine and shoulder girdle
Go up one side and come down on opposite side
Remember: Posterior ribs descend medial to lateral Anterior ribs descend lateral to medial
Structures Visualized:
Breast Tissue
Posterior Ribs
Anterior Ribs
Scapula
Clavicle
Spine
Thorax cage dz that may stimulate chest dz:
Bony metastasis
Rib / Clavicle fractures
Searching the “Mediastinum”
An organized search of the mediastinum is complicated because of all the overlapping structures.
Start with a global look for contour abnormalities, then follow with a more detailed search
Three searches of the mediastinum:
1. Trachea and carina
2. Aorta and the heart
3. Hilum
Three searches of the mediastinum:
1. Trachea and carina
2. Aorta and the heart
3. Hilum
Three searches of the mediastinum:
1. Trachea and carina
2. Aorta and the heart
3. Hilum
Three searches of the mediastinum:
1. Trachea and carina
2. Aorta and the heart
3. Hilum
Searching the “Lungs” Since most chest x-rays are ordered to
evaluated for lung disease, so the lungs are examined last.
They are important, so their evaluation should be more through, therefore we evaluate them twice. Once individually Second time comparing right and left
Structures Visualized:
Costophrenic angles
Lung fields
Pulmonary vasculature
Right minor fissure
Left Lateral Chest Film Valuable radiographic study Helps to better localize lesions Allows to visualize overlapping
tissues Allows the visualization of hidden
pathology
Searching the Lateral Chest Film
The pattern is the same:1) Abdomen2) Thoracic cage strutures3) Mediastinum4) Lungs
Search Pattern:
Abdomen
Thoracic cage and bones
Mediastinum
Lungs
Search Pattern:
Abdomen
Thoracic cage and bones
Mediastinum
Lungs
Search Pattern:
Abdomen
Thoracic cage and bones
Mediastinum
Lungs
Search Pattern:
Abdomen
Thoracic cage and bones
Mediastinum
Lungs
Search Pattern:
Abdomen
Thoracic cage and bones
Mediastinum
Lungs
What to look for… Abnormal density
Usually air versus water Abnormal shape
Lung field Mediastinum
Abnormal size Lung field Mediastinum
Abnormal location Hemidiaphragm, hila, mediastinum, trachea,
fissure, vasculature
But before that we need to have a good understanding of Normal Radiographic Anatomy
Let’s look at some of the visual abdominal
structures
Stomach gas bubble
Splenic flexure of the large intestines
Liver
Left Hemidiaphragm
Right Hemidiaphragm
Let’s look at the Bony thorax
Ribs
Spine
Clavicle
Scapula
Chest wall
Let’s look at the Bony thorax
Ribs
Spine
Clavicle
Scapula
Chest wall
Trachea on CXR
Let’s look at the normal Mediastinal Structures
Hilum
Vessels
Aortic Arch
Pulmonary Artery
Left Atrium
Left Ventricle
Inferior Vena Cava
Right Atrium
Ascending Aorta
Superior Vena Cava
Descending Aorta
Aortic Knob/Arch
Ascending Aorta
Right Ventricle
Inferior Vena Cava
Left Ventricle
Left Atrium
Upper
Middle
Lower
Lung Fields
Let’s look at the normal Lung Structures
Retrosternal Clear Space
Retrocardiac Clear Space
Lateral Costophrenic Sulci
(Recesses, Angles)
Cardiophrenic Sulci
(Recesses, Angles
Posterior Costophrenic Sulci
(Recesses, Angles)
What are the Pulmonary Fissures?
They are the coming together of the visceral pulmonary pleura.
Right lung Oblique (major) fissure Horizontal (minor) fissure
Left Lung Oblique (major) fissure
Horizontal Fissure
Right Oblique Fissure
Left Oblique Fissure
LUL
LLL
RUL
RML
RLL
A closer look at
the fissures
References Felson’s Principles of Chest Roentgenology: A
Programmed Test, 2nd Edition. Goodman, Lawrence R.; W.B. Saunders Co., 1999.
Pocket Atlas of Radiographic Anatomy. Moller, TB et al.; Thieme Medical Publishers, 1993
Clinical Imaging with Skeletal, Chest and Abdomen Pattern Differentials, Dennis Marchiori, ed. (WN 180 M317c)