12/10/07

PEGGY’S POINTS

Is the heart larger on a PA or AP chest

film?

AP – Due to magnification

PA

AP

Why do we say cardiac silhouette instead of heart size?

Pericardial effusion can enlarge the silhouette but not the heart itself.

Note the large effusion

What are the 3 radiographic stages of CHF ?

1. Pulmonary venous hypertension 2. Interstitial edema 3. Alveolar edema

Normal vascularity

Pulmonary venous hypertension

Interstitial edema

Alveolar edema

COMPARE THE STAGES

Normal vascularity

Plumonary venous

hypertension

Interstitial edema

Alveolar edema

Where is the earliest sign of pleural effusion seen on a PA/Lat chest film?

Blunted posterior costophrenic angle

What is a subpulmonic effusion ?

Fluid between the lung and diaphragm

How do you determine if a pleural effusion is free flowing?

A decubitus chest film

How do you determine if a right sided effusion is free flowing?

Order a right lateral decubitus--(right side down) chest xray.

What distinguishes atelectasis from consolidation?

Volume loss

What are the 2 considerations for an

opacified hemi thorax?

1-Obstructed bronchus 2-Large pleural effusion

How do you tell the difference?

Mediastinum shifts

Towards the side of a bronchial obstruction.

Away from a large pleural effusion.

What distinguishes a pneumothorax from a skin

fold ?

Pneumothorax will show a white line at the border.

A skin fold typically shows a black line at the border.

Cause of a spontaneous pneumothorax……

Rupture of a sub pleural bleb typically in the upper lobe.

What radiograph is used to evaluate for possible pneumothorax ?

Expiratory chest x-ray

inspiration

expiration

Expiratory CXR will show a pneumothorax more easily as relative volume will be larger and more easily seen.

What is the silhouette sign ?

Silhouette sign indicates loss of visualization of an edge, as density difference between lung and heart

is lost.

What is an air bronchogram ?

Air filled bronchi surrounded by opacified lung.

What does a Hampton’s hump signify ?

Hampton’s hump is a triangular lung infarct on a CXR in patients with a pulmonary embolus.

What is a pseudotumor ?

A Pseudotumor is loculated pleural fluid that simulates a lung mass.

More examples of

pseudotumors

What is the AP window?

It is the potential space between the aortic arch and the left pulmonary artery.

Do you see the mass?

Correlate the CT biopsy with the film above.

An X-ray in the department can be made with a more powerful generator (3phase vs single phase for portable).

This allows for a shorter exposure time resulting in decreased patient motion. A film in the department also allows for easier use of an xray grid which can absorb scatter and improve the contrast of the film for better detail.

Why is an x-ray made in the x-ray department of better quality than a

portable x-ray ?

ABDOMEN

What is the exam to evaluate for

pneumoperitoneum?

Upright abdomen film

If a patient can not stand what radiograph can be substituted?

Left lateral Decubitus

pneumoperitoneum

Liver side UP

Patient lying on their LEFT side.==

Why is an upright chest film included in a acute abdomen series?

• Lower lobe pulmonary disease can sometimes present with abdominal symptoms.

• Pneumoperitoneum can sometimes be more easily visualized on an upright chest xray.

What is the significance of curvilinear calcifications along the spine?

You have to consider an abdominal aortic aneurysm.

Large aortic aneurysm

What separates an illeus from a small bowel obstruction?

An illeus should involve large and small bowel

symmetrically vs SBO which will have little to absent colon

gas.

IODINATED CONTRAST is used for patients at risk of GI tract perforation. It is also of value in patients with fecal impaction to draw fluid into colon to help evacuation.

Studies on patients for pending GI surgery are sometimes requested using iodinated contrast. Barium from GI studies can limit future CT scans due to artifact from retained barium.

****

Barium contrast is used for all other patients especially if there is the risk of aspiration. The osmotic effect can promote pneumonitis in lungs with aspiration.

If in doubt --- CALL XRAY AND ASK.

The contrast being excreted by the kidney can obscure a calcified

calculus.

Why is a non contrast CT preformed for possible urolithiasis?