Cardiac blood pool scan

Equilibrium study

Blood pool agent

Tc labelled RBC

Technique

• patient in normal sinus rhythm
• IV administration of Tc Labelled RBC
• ECG gated – with R wave gating
• minimum of 16 frames/cardiac cycle
• at rest and exercise

Analysis

• qualitative analysis
• quantitative analysis
• functional parameters
  • wall motion assessment (regional and global)
  • ED and ES ventricular volume
  • stroke volume
  • cardiac output
  • ejection fraction ( LV and RV)
  • regurgitant fraction (stroke index ratio)
  • ventricular filling and emptying rates
  • cardiac shunt quantitation
    • left to right shunts – evaluated using the first transit technique (NOT equilibrium)
    • right to left shunts – evaluated using Tc99m labelled macro-aggregated albumin and comparing ratio of tracer in the lung to tracer gaining access to the systemic circulation

Clinical settings for assessment

• acute myocardial infarction (AMI)
• coronary artery disease (CAD)
• evaluation after coronary artery bypass graft surgery
• cardiomyopathy / myocarditis
• assessment of drug therapy
• pulmonary disease
  • RV enlargement
  • cor pulmonale
  • normal LV ejection fraction, wall motion and chamber size strongly suggests a pulmonary aeitiology

First pass study

This is obtained by injecting a compact bolus of suitable radiopharmaceutical intravenously.

• major advantage : data collected rapidly over very few cardiac cycles allows measurement of ventricular function at peak stress during exercise ventriculography

• major disadvantage : counting statistics are low and only a limited number of views are possible