Exam 1 material Flashcards
Positioning for a chest rad
Pull legs!
Manubrium to last rib = lateral and VD
Chest rads, when do we want to make the exposure?
INSPIRATION
more air in the lungs will make better contrast
For chest rads we need ____ contrast image.
This means ___mAs and ____kVp for film
LOW contrast
low mAs, high kVp
(motion is an issue so low time)
“abnormal” usually means…
increased opacity
Non-pathological things that lead to increased lung opacity
- radiographic technique: underexposed/low contrast
- Aeration: Atelectasis is bad
- lungs always look worse in lateral views
- sedation leads to atelectasis
- Habitus: overlying tissue increases opacity in image
Issue with lateral rads and lungs
the increased opacity in the “down” lung reduces lesion conspicuity in the dependent hemithorax (silhoutte sign)
Recumbent atelectasis occurs quickly, increases with chemical restraint. PPV when anesthetized. ALWAYS make R and L lat rads. Both VD and DV good too
Checklist for looking over thoracic rads
heart
pulmonary vessels
lungs
pleural space
mediastinum
trachea
bones
Label anatomy of the diaphragm
A- crus/crura
B- dome
Crura attach to the ventral aspect of ____ and cause confusion why?
L3 and L4
create an indistict cortex that is sometimes confused with an aggressive lesion
Label the diaphragm anatomy
A- aorta
B- esophagus
C- caudal vena cava
What helps us determine L or R lateral view?
The most dependent (down) crus is USUALLY more cranial
does not work in all dogs, not in cats
What side is this dog laying on?
Right lateral
R crus is more cranial
CVC attaches to R crus
therefore CVC blends with most cranial crus
What side is this dog laying on?
Left Lateral
L crus more cranial
CVC by passes the most cranial crus and attaches to more caudal crus
R and L crus are more divergent
Fundus of stomach caudal to L crus
Label the lateral views R or L
Acquired Diaphragmatic Hernias
- abdominal viscera protrudes thru the diaphragm (compress lungs)
- most common cause: trauma
- may or may not result in CS
- may have concurrent pleural fluid
- not easy to dx
- US-experts, Barium study*
- remove pleural fluid if present by thoracocentesis and repeat rads
Traumatic Diaphragmatic Hernia
- border effacement of diaphragm = siloutte signs
- abdominal viscera in pleural space
- abnormal location of abdominal structures
Pylorus displaced to the left and cranially
HBC, cat- Hernia
Anything abnormal?
What does this barium study show us?
Anything abnormal?
What abnormalities are in this rad?
Peritoneopericardial Diaphragmatic Hernia (PPDH)
- Abdominal viscera herniates into pericardial sac through a congential defect b/t ventral thorax and abdomen
- Sometimes associated with fewer than normal sternebrae
- Usually an incidental finding, rarely need to be corrected
- occasionally produces CS
- Round, enlarged, cardiac silhouette
- Heterogenous opacity if gas or large amount of fat present (fat=radiolucent)
- Confluent silhouette between heart and diaphragm
What abnormality is seen?
PPDH- Peritoneopericardial diaphragmatic hernia
What abnormality is seen?
PPDH- Peritoneopericardial diaphragmatic hernia
What does this CT reveal?
PPDH
Hiatal hernia
- What kind is more common?
- What view is better to see them?
- How can we confirm?
- Portion of fundus herniated through esophageal hiatus
- two types:
- sliding (more common in animals)
- paraesophageal
- Often manifests in patients with partial upper airway obstruction= brachycephalics
- Most common to see in L lat view but not in R lat or VD
- May have to give barium to confirm
What abnormality is seen here?
Hiatal Hernia
What lesions are often missed in the thoracic view?
RIBS are often ignored
many rib lesions are missed
critical part of thoracic assessment
(fakeouts from superficial nodules)
Costal cartilages on radiographs
- Commonly mineralize
- even in young dogs
- Once mineralized (stiff) exuberant calcifications can form around the costochondral junction
- commonly confused with tumors, infection or lung nodules
What is detected in this radiograph?
Micro-fractures! No pain, no issue!
NORMAL
Skin Nodules
(what priciple is this?)
- Can appear as lung nodules
- nodules are very distinct
- may need additoinal views
- can apply contrast medium to area and retake rad
Superimposition
Rib fractures
Rarely clinically significant
can be spontaneous in cats (w/ dyspnea)
healing pattern same as in long bones
Anything abnormal in these rads?
fractured ribs
Thoracic wall masses
What type of thoracic mass is this?
What type of thoracic mass is this?
Name the abnormality
Name the abnormality
Rib tumor
Name the abnormality
Rib tumor
Rib tumors
- usually late by the time the O brings P in
- Pleural effusion typically present
- Usually mesenchymal
- OSA vs CSA
- Caudal ribs
- Iceburg effect (see pic)
Mediastinum
- The space b/t right and left pleural sacs; bounded by mediastinal pleura
- Extends from thoracic inlet to diaphragm
-
NOT a closed cavity
- communicates with neck and retroperitoneal space
- Fenestrated: usually does NOT contain unilateral dz
What number(s) show the mediastinum?
7- cranial mediastinum
8- caudal mediastinum
Name some structures located within the mediastinum
Heart
Vena cava
Esophagus
Aorta
Azygos vein
Mediastinal reflections
locations where the mediastinum deviates from the midline
Cranioventral mediastinal reflection
Border b/t right cranial lung lobe and the cranial part of the left cranial lobe
Cranially, the left lung extends to the right
Caudally, the right lung extends to left
What can be seen in this rad from a young dog?
Caudoventral mediastinal reflection
Border b/t the accessory lobe (R Lung) and the left caudal lobe (L lung)
the left aspect of the accessory lobe crosses midline pushing mediastinal pleura to the left
The thickness of the caudoventral mediastinal reflection depends on…
the amount of fat present
Mediastinal shift
- Atelectasis is the most common cause
- Displacement of heart is the most reliable sign
- Helps differentiate lung dz from atelectasis
- lung opacity, no heart shift = dz
- lung opacity, heart shift = atelectasis
Dz or atelectosis?
atelectosis
Common causes of mediastinal masses
- lymph nodes enlargement
- thymus enlargement
- esophagus enlargement
Mediastinal Lymph Nodes
- Green
- Blue
- Red
- Green: Sternal= drain abdomen**
- Blue: Cranial Mediastinal
- Red: Tracheobronchial= lungs are drained by their (Hilar LNs)
Cranial mediastinal LN
thoracic wall, trachea, thyroid
Tracheobronchial LN
AKA Hilar LN
Drain Lungs
Sternal LN
Drain mammary glands and peritoneum
Peritoneal dz may cause sternal lymphadenopathy
How to Dx the cause of a mediastinal mass?
Rule outs can be narrowed based on location
sonography or CT
Usually need cytology
Describe abnormality
Cyst? Mass? Ultrasound!!!
Cyst is better px than mass
What abnormality is seen here?
Moderate Tracheobronchial Lymphomegaly
What abnormality is this?
Bow legged cowboy sign
Moderate Tracheobronchial Lymphomegaly
Confounding effect of pleural fluid
- prevents identification of mediastinal mass
- need to take additional steps
- drain fluid and re-radiograph bc fluid hides things
- US- fluid is our friend w/ US!
This radiograph of a cat shows?
Pleural fluid
Cat with pleural effusion had US of lungs done. What do we see?
soft tissue mass
Pneumomediastinum
What view?
- means air in the mediastinum
- mediastinal structures become more conspicuous due to contrast provided by mediastinal gas
- Structures not normally visible are seen
- Pneumomediastinum can progress to pneumothorax if distension is severe
- Pneumothorax will not progress to pneumomediastinum
- LATERAL VIEW is the $$$ shot
Causes of pneumomediastinum
- Neck wound- dog fights
- Hole in trachea
- bite wound
- jugular vein puncture miss
- endotracheal tube cuff overinflation
- Retrograde flow along airways from intrapulmonary rupture= “Macklin effect”
What is abnormal about this chest rad?
Pneumomediastinum
What abnormality is seen in this rad?
Mild pneumomediastinum
not normal!
What abnormality is detected?
TRICK
its normal! :)