Transcript Radiology Packet 1 - University of Prince Edward Island

Radiology Packet 2
Normal Thorax
Tracheal Diameter
Tracheal Diameter
Tracheal Diameter
• General estimation of tracheal size can be provided by comparing
the diameter of the trachea to the diameter of the proximal 3rd rib in
the lateral radiographic projection.
• Trachea should be ~3x the width of proximal 3rd rib.
• More precise evaluation of tracheal size can be provided by
comparing the ratio of the tracheal diameter to the height of the
thoracic inlet.
• Tracheal lumen diameter is then divided by the thoracic inlet
measurement to determine the ratio.
Anesthesia vs awake thoracic
radiographs
• anesthetized
• awake
Anesthesia vs awake thoracic
radiographs
• Thoracic volume is diminished due to lack of deep inspiration.
• Heart appears larger due to diminished thoracic volume.
• Lungs have increased soft tissue opacity since they are less fully
aerated.
• On the DV view the right lung is more opaque than the left and the
heart is shifted toward the right chest wall due to recumbency
induced partial atelectasis.
• On lateral view there is a gas dilated esophagus. This is an
incidental finding due to aerophagia during induction and/or muscle
relaxation. It’s appearance is identical to pathological
megaesophagus.
Young dog thorax
• Radiographs of a 9mth old canine
Young Dog thorax
• In VD view there is a triangular soft-tissue opacity
structure in the left hemithorax immediately cranial to
the cardiac silhouette – This is the thymus.
• In the lateral view there is a narrow band of increased
soft-tissue opacity along the cranial border of the heart.
This is the result of summation of the thymus with the
heart.
• The thymus is rarely visible in young cats.
Dorsoventral and Ventrodorsal
Positioning
Dorsoventral and Ventrodorsal
Positioning
• There is an overall increase in opacity
throughout the lung fields - this is a result of
pleural effusion.
• In DV view there is clear visualization of the
caudal pulmonary vessels.
• In VD view the caudal pulmonary vessels are not
visible.
Right vs left lateral thoracic
radiographs
Right vs left lateral thoracic
radiographs
Right vs left lateral thoracic
radiographs
• When the patient is positioned in right lateral
recumbency the heart shifts toward the right and leftsided apex is highlighted.
• The cardiac silhouette is somewhat ovoid in shape with a
rounded point at the apex.
• In left lateral the heart shifts toward the left and the apex
is “rolled under” the heart and is no longer visible.
• This gives the cardiac silhouette a rounded appearance.