The CardioPhiles

LV Syst Fcn

•Radioactivity within the blood pool

–First-pass radionuclide ventriculography

–Equilibrium radionuclide ventriculography (Planar)

–Equilibrium radionuclide ventriculography (SPECT)

•Radioactivity within the myocardium

–ECG-gating SPECT

 

Equilibrium radionuclide ventriculography

•Tc-99m fixed to pt’s own RBC’s

•Lower limit of nl EF 50%

•Limitations: –pt shouldn’t move –most planar - overlap, multiple views (LAO)

•SPECT experimental –assumption that cardiac performance will stay stable

(not the case with Fr PVC’s PAC’s)

Zaret B & Beller GA. 2005

 

First-pass radionuclide ventriculography

•More technically demanding

•Can be used routinely at the time of any Tc-99m labeled pharmaceutical injection

•Basic assumption - enough time for mixing

•Presence of significant change in cardiac cycle length or arrhythmia may invalidate the data

Zaret B & Beller GA. 2005

 

•EF = ED Counts – ES Counts x 100% ED Counts •The larger number of counts the smallest the statistical error is •With low EF’s there is a tendency for higher errors

 

Gated SPECT (Functional Analysis)

•Very good agreement between gated-SPECT & gold standard –probably more accurate than 2D studies – uses 3D algorithms for detection of endocardium/no geometric assumption •The normal threshold for EF slightly lower than that measured using other imaging modalities, or ~46-47% due to 3-4 point underestimation associated with use of only 8 gating intervals •For 16 gating intervals nl is >= 50% Hurst’s. The Heart. 2001. 10th Ed.

 

Wall motion is best evaluated in linear grey scale without computer-derived edges

Wall thickening is best evaluated with color scale, and is related to the increase in counts between diastole and systole