CT/MRI

Question 2

Benefits of CT for dx heart dz

Answer 2

• Cross sectional images
• Assessment of cardiac fct and precise definition of cardiac anatomy with ECG gating or ms CT scanner
  o IV injection of contrast agent used to define blood pool

Question 3

Benefits of MRI for dx heart dz

Answer 3

• High natural contrast btw blood and cardiovascular structures → no contrast required
  o Cardiac gating permits to ↓ motion artifact from heart motion throughout cardiac cycle
   ECG or peripheral pulse
• Modality of choice for imaging soft tissue details
• Useful information: cardiovascular morphology, function, tissue character
  o Presurgical planning

Question 4

Advantages of MRI

Answer 4

o No contracts needed with high soft tissue contrast
o Non invasive
o High spatial resolution
o Few safety drawbacks
o Cross sectional images in any plane (unlike CT)

Question 5

Disadvantages of MRI

Answer 5

o Long scanning times
o Require general anesthesia → affect measure of systolic function

Question 6

utility of MRI

Answer 6

• Confirm less common structural heart diseases
  o Aortic coarctation
  o Vascular ring abnormalities
   Persistence of Ao arch +/-90% of vascular ring anomalies
  o Cardiac neoplasia: heart base tumors, hemangio
  o Congenital diseases: PDA
  o Valvular stenoses and insufficiencies
• Thoracic abnormalities: if echo/CTX did not confirm abnormality
  o Mediastinal disorders
  o Sternal, cranial, mediastinal, tracheobronchial lymphadenotpathy
  o Cr/Ca mediastinal mass
  o Intrathoracic vascular abnormalities
  o Ao/cardiac mineralization
   Older, large breed dogs
   Degenerative changes
   Descending Ao: atherosclerosis, spirocercosis, cushing
  o Vascular dissection, aneurysm, stenosis
  o Parasitic infection
  o Pericardial rupture/cardiac herniation
  o Cava thrombus/obstruction → Budd-Chiari-like syndrome