Rui Domingues, MD Lincoln Mental and Medical Center September 2008 Pulmonary Radiology Rui Domingues, MD Lincoln 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 A good understanding of normal anatomy 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

Air Fat Glass Test Tube Water Metal Bone + Water

Differential Absorption Black 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 Additional Views PA Left Lateral Apical Lordotic Inspiration / Expiration

PA CXR Left Lateral CXR

Apical Lordotic CXR Allows for better visualization of the Apices of the lungs

Normal positioning for PA Chest Expiration study Helps visualize: Inspiration Inspiration study Normal positioning for PA Chest Expiration study Helps visualize: - Small Pneumothorax - Air Trapping Dz (Emphysema) - Bronchial obstruction Visualizes respiratory excursion

How to approach an X-ray?

Reading a Chest X-ray First thing: Then perform your search pattern 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 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: Abdomen Thoracic cage strutures 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 Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

What to look for… Abnormal density Abnormal shape Abnormal size Usually air versus water Abnormal shape Lung field Mediastinum Abnormal size 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 Left Hemidiaphragm Stomach gas bubble Let’s look at some of the visual abdominal structures Splenic flexure of the large intestines Right Hemidiaphragm Liver

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

Let’s look at the normal Mediastinal Structures Trachea on CXR Hilum Let’s look at the normal Mediastinal Structures

Superior Vena Cava Vessels Aortic Arch Ascending Aorta Pulmonary Artery Right Atrium Left Atrium Left Ventricle Inferior Vena Cava

Aortic Knob/Arch Descending Aorta Ascending Aorta Left Atrium Right Ventricle Left Ventricle Inferior Vena Cava

Let’s look at the normal Lung Structures Lung Fields Upper Let’s look at the normal Lung Structures Middle Lower

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

Right Oblique Fissure Horizontal Fissure Left Oblique Fissure

A closer look at the fissures RUL LUL RML RLL LLL

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)