An Introduction to X-ray Interpretation

September 2018 Disclosures

None to report Introduction Objectives

1) Chest X-rays • Introduction • Patient and Image Data • Image Quality and Artifact • The Obvious Abnormality • Describing and Locating Abnormalities • Review Areas 3) Musculoskeletal X-rays • The Clinical Question • Introduction • Bone Anatomy • Joint Anatomy 2) Abdominal X-rays • Systematic Approach • Viewing Principles • Introduction • Image Data and Quality • Bowel Gas Pattern • Soft Tissues • Bones • Calcification and Artifact 1) Chest X-rays

Introduction Patient and Image Data Image Quality and Artifact The Obvious Abnormality Describing and Locating Abnormalities Review Areas The Clinical Question Introduction

Systematic Logical Flexible

Anatomical structures to check: 1. Trachea and bronchi 2. Hilar structures 3. zones 4. Pleura 5. Lung lobes and fissures 6. Costophrenic angles 7. Diaphragm 8. 9. Mediastinum 10. Soft tissues 11. Bones Patient and Image Data

• Patient ID

• Date and Time

• Image Projection

• Image Annotations (Standard PA View) Image Quality and Artifact

Mnemonic – RIP:

• R - Rotation - Spinous processes at midpoint between medial ends of the clavicles?

• I - Inspiration - 5 to 7 anterior ribs intersecting the diaphragm in the mid-clavicular line?

• P - Penetration - Spine visible behind the heart? The Obvious Abnormality

The elephant in the image!

If there is an elephant in the image, don't ignore it! Describe it in detail and then use your system to continue examining the image Describing and Locating Abnormalities

• 'Shadowing', 'opacification', 'increased density', 'increased whiteness' are all acceptable terms • 'Lesion descriptors' may lead you towards a diagnosis • Be descriptive rather than jumping to a diagnosis

The Silhouette Sign • Tissue involved - Lung, heart, aortaetc. Normal adjacent anatomical • Size - Large/Small/Varied structures of differing • Side - Right/Left - Unilateral/Bilateral densities form a crisp • Number - Single/Multiple contour or 'silhouette'. Loss • Distribution - Focal/Widespread of a specific contour can help • Position - Anterior/Posterior/Lung zone etc. determine the position of a • Shape - Round/Crescentic/etc. disease process. The • Edge - Smooth/Irregular/Spiculated silhouette sign is a misnomer • Pattern - Nodular/Reticular(net-like) - it should really be called the • Density - Air/Fat/Soft-tissue/Calcium/Metal 'loss of silhouette' sign Review Areas

Mnemonic – ABCDE:

• Apices - Pneumothorax? • Bones/soft-tissues - Fractures/density? • Cardiac shadow- Consolidation/mass? • Diaphragm - ? • Edge of the image - Unexpected findings?

• Airway – Is the trachea central? • Boundaries and both – Lung borders, consolidation etc. • Cardiac – Heart size • Diaphragm - Pneumoperitoneum? • Everything else – Soft tissues/fractures The Clinical Question

No clinical information provided:

Without clinical information this patient may be considered to have a in the left upper zone, and started on antibiotics The Clinical Question

Clinical information provided:

• Recent increase in • No fever or productive • Left shoulder and arm pain • Heavy smoker • Weight loss

Findings:

• Left apical shadowing • Raised left hemi-diaphragm • Increased extra-thoracic soft tissue density with displacement of the scapula on the left The Clinical Question

Interpretation in view of clinical details:

• Cancer - Smoker with weight loss and left apical consolidation/mass and no clinical features of infection • Recent increase in • Phrenic nerve palsy - Increased shortness of breath shortness of breath and raised • No fever or left hemi-diaphragm productive cough • Left shoulder and • Brachial plexopathy - Arm pain arm pain and axillary soft tissue swelling • Heavy smoker • Weight loss Key Points

• Patient identity • Image data • Image quality • The obvious abnormality - description/location • Systematic check of anatomy • Review areas • Consider the clinical question 2) Abdominal X-rays

Introduction Image Data and Quality Bowel Gas Pattern Soft Tissues Bones Calcification and Artifact Introduction

• Although anatomy of the abdomen is complicated, many structures are not clearly defined on a radiograph of the abdomen, and therefore cannot be fully assessed

• A systematic approach to abdominal X-ray interpretation is therefore relatively straightforward and involves assessment of the bowel gas pattern, soft tissue structures, and bones Image Data and Quality

• You should always check that the image data refers to the correct patient and that the X-ray is the current examination

• Abdominal X-rays provide limited information at the best of times. When an image is of low quality there is often little that can be improved and therefore repeating images is usually unfruitful

• The whole abdomen should be included

• Often two images are required to view the entire abdomen from the diaphragm to the hernial orifices, and from left to right abdominal walls

• Large patients may require more images Image Data and Quality

• Supine Anterior-Posterior (AP) projection Most common type

• Erect chest X-ray Perforation of the bowel suspected

• Decubitus positioning Patient to ill to be positioned erect Consider CT scan Bowel Gas Pattern

• Any part of the bowel may be visible if it contains gas/air within the lumen

• Gas/air is of low density and forms a natural contrast against surrounding denser soft tissues

• The upper limit of normal diameter of the bowel is generally accepted as 3cm for the small bowel, 6cm for the colon and 9cm for the caecum (3/6/9 rule)

• It is often difficult to differentiate between normal small and large bowel

Normal small bowel Normal large bowel • Central position in the abdomen • Peripheral position in the abdomen • Valvulae conniventes - mucosal (the transverse and sigmoid colon folds that cross the full width of the occupy very variable positions) bowel • Haustra •Contains faeces Soft Tissues

Abdominal X-rays provide a limited means of assessment of soft tissue structures

Soft tissue organs visible on abdominal X-rays include:

• Liver – Bland area of grey in the RUQ. Gallbladder is only rarely visible

• Spleen – Lies in the LUQ immediately superior to the left kidney

• Kidneys - Lie at the level of T12-L3 and lateral to the psoas muscles

• Psoas muscles - Lateral edge is demonstrated as a near straight line

• Bladder (within pelvis) – Similar density to surrounding structures. Varying density depending on how full it is

• Lung bases (within thorax) - pass behind the liver and diaphragm in the posterior sulcus of the thorax Bones

• Systematically examine the bones

• All bones are better visualized with dedicated images

• Bones act as landmarks for other structures

• The lower ribs • Lumbar vertebrae • Sacrum • Coccyx • Pelvic bones • Proximal femurs Calcification and Artifact

• Densities that cannot be explained by anatomical structures are often seen on abdominal X-rays. These may be artifactual (e.g. due to medical devices) or due to soft tissue calcification • This calcification may not be pathological, but differentiating significant calcification from that which can be ignored is not always straightforward • The clinical features must be considered whenever abnormal calcification is suspected. • Other investigations may be required Key Points

• Check the patient details • Assess quality • Systematically review bowel gas, soft tissues, bones and abnormal calcification 3) Musculoskeletal X-rays

Bone Anatomy Joint Anatomy Systematic Approach Viewing Principles Bone Anatomy

• When describing the location of a bone abnormality within a growing bone you can refer to its position in the diaphysis (shaft) metaphysis or epiphysis (end)

• It is also correct to use simple descriptive terms such as - shaft - proximal/distal end – cortical (denser and therefore whiter) – medullary (fine trabecular pattern) - articular surface

Sesamoid: A sesamoid bone is a bone that ossifies within a tendon. The largest is the patella. Sesamoid bones are also present at the first metatarsophalangeal joint (big toe) and the first metacarpophalangeal joint (thumb)

Apophysis: An apophysis is a normal developmental outgrowth of a bone which arises from a separate ossification centre, and fuses to the bone later in development. An apophysis usually does not form a direct articulation with another bone at a joint, but often forms an important insertion point for a tendon or ligament Joint Anatomy

• Most joints are synovial and comprise two articulating bones lined with hyaline cartilage and contained by a synovial lined capsule

• Although soft tissues such as cartilage and capsular structures are of low density, and so are less well-defined on X-ray images, it is a mistake to think they are not visible Systematic Approach

• Patient and image details

• Bone and joint alignment

• Joint spacing

• Cortical outline

• Bone texture

• Soft tissues Viewing Principles

• 2 views + are better than 1

• Compare with other side

• Compare current with previous images

• 'Treat the patient and not the X-ray!‘

• Look for the unexpected

• Image Quality

• Artifact Key Points

• Plain radiographs provide information about bone, joint and soft tissue structures • Be systematic • Look at all views available • If available compare with old images • Look for the unexpected • Assess image quality and if clinically appropriate consider requesting a repeat X-ray Recap

1) Chest X-rays • Introduction • Patient and Image Data • Image Quality and Artifact • The Obvious Abnormality • Describing and Locating Abnormalities • Review Areas 3) Musculoskeletal X-rays • The Clinical Question • Bone Anatomy • Joint Anatomy • Systematic Approach 2) Abdominal X-rays • Viewing Principles • Introduction • Image Data and Quality • Bowel Gas Pattern • Soft Tissues • Bones • Calcification and Artifact References • https://www.radiologymasterclass.co.uk*** • https://radiopaedia.org • http://www.orthobullets.com/