Equilibrium Radionuclide Angiocardiography (ERNA)

T. D. Ruddy, MD University of Ottawa Heart Institute, Ottawa, ON

Standard ERNA Protocols and Associated Patient Radiation Doses1

Equilibrium radionuclide angiocardiography (ERNA), also termed multigated acquisition scan (MUGA), is an accurate and highly precise method to evaluate left ventricular global and regional function. Multiprojection planar imaging is performed routinely. Left ventricular ejection fraction (LVEF) and peak diastolic filling rate are derived by quantitative analysis. Single-photon emission computed tomography (SPECT) affords the additional benefits of quantification of LV and right ventricle (RV) volume and RV ejection fraction and better definition and localization of regional wall motion abnormalities. Echocardiography has supplanted ERNA for most routine clinical evaluation of ventricular function due to its ready availability and lack of ionizing radiation. However, ERNA remains the diagnostic method of choice in patients who are being followed for chemotherapy cardiotoxicity where changes in LVEF must be accurately quantified. Also, ERNA is useful in patients in whom the LVEF must be known to qualify them for certain interventions such as resynchronization therapy. Finally, in patients for whom echocardiography is technically suboptimal or inadequate, ERNA is of considerable value.

Injected Activity  Effective Dose Estimate
 20-35 mCi /70kg 99mTc-labeled RBCs 3 to 5.2 mSv for 20 mCi
3.75 to 6.5 mSv for 25 mCi
 20-35 mCi /70kg 99mTc-labeled RBCs 3.75 to 6.5 mSv for 25 mCi
5.25 to 9.1 mSv for 35 mCi


Recommendations to Decrease/Limit Patient Radiation Exposure