Importance of imaging for the cardiac surgeon

Cardiac CT, MRI Imaging for the Surgeon

Dr. S.K. Varma. MS, FRCS(Ed), MCh, DNB, FIACS

Chief Cardiothoracic Surgeon

KG Hospital, Coimbatore 641018

www.skvarma.com

Cardiac Imaging Modalities

• CXR

• Echo

• CT

• MRI

• Nuclear Scintigraphy

• Cardiac Catheterisation

Good CT Imaging

• 64 slice

• ECG gated

• Preferably dual source

• HR 60/min, regular rhythm

Coronary Artery Anatomy

Coronary Anatomy (3D Reconstruction)

• Multiple planes

• Multiple views

• Exact course

• Intramyocardial course

Anatomy distal to total occlusion

Post PCI stent evaluation

Post CABG graft evaluation

Aortic calcification

Distance from sternum (Redo procedures)

Congenital Heart Disease

Anatomy of the aortic root

Anatomy of Aneurysms

Anatomy of Aortic Dissection

Anatomy of access vessels (TAVI, endovascular aortic stenting)

To r/o pulmonary embolism

Evaluation of Pericardial Disease

Cardiac MRI for the Surgeon

Good MRI study

• ECG gated

• 1.5 tesla

• Contrast enhanced

Myocardial viability

Dobutamie/ adenosine stress MRI

Cardiac volumes & masses

Global/regional contractility

Myocardial tissue charecteristics

• Oedema

• Inflammation

• Metabolism

• Fibrosis

CT or MRI ? How to decide?

• CT

• Structural evaluation

• Coronary anatomy

• Avoid magnetic fields

• Iodine based contrast

• MRI

• Functional evaluation

• Anatomy of infarct

• Avoid radiation

• Gadolinium based

Contraindications to CT

• Avoid radiation (Pregnancy)

• Anaphylaxis to iodine based contrast

• Fast heart rate, irregular rhythm

Contraindications to cardiac MRI

• Prosthetic valve

• Pacemaker / AICD

• Coils / stents

• Occluder devices

• Cochlear implants

• Critically ill patients (ventilator, inotrope dependent)

Contrast Induced Nephropathy

• >25% increase in renal function within 48-72 hrs of IV contrast

• Can occur as long as after 7 days after

• Direct cytotoxicity + vasoconstriction on PCT

• Common with hypo-osmolar contast

• Less with iso-osmolar contrast

• Common in elderly, diabetics, CKD, dehydration

Contrast Induced Nephropathy

• Volume of contrast

• Treatment – hydration, forced diuresis, N Acetyl cystine, NAHCO3, high dose statins

Summary

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