Radiology, Vol 139, 719-723, Copyright © 1981 by Radiological Society of North America
A new scintigraphic technique for assessment of right atrial function
A Marmor, DR Biello, KS Sampathkumaran, EM Geltman, BA Siegel and R Roberts
Gated radionuclide imaging with 99mTc-labeled red blood cells was employed
to assess changes in right atrial (RA) volume in 17 subjects. Studies were
repeated within two hours in five of 12 normal subjects and at two and ten
days after infarction in five patients. Time- activity curves were
generated for the RA and right ventricle (RV) from variable regions of
interest defined by automatic edge detection. The RA time-activity curve
exhibited four phases: filling, early emptying, equilibration, and late
emptying. Repeated measurements of RA early emptying rates correlated
closely in normals (r = 0.93). Early RA emptying and RV filling rates
corresponded closely (r = 0.89). In four patients with infarction, the RA
emptying rate was slowed on the first study but had normalized by 10 days.
In a patient with inferior infarction and suspected RV infarction, the RA
emptying rate was depressed and remained so for 10 days. Thus, relative
changes in right atrial volume can be assessed reproducibly by a
radionuclide technique, which is relatively independent of geometric
assumptions. This technique offers great promise as a method to assess
atrial function in health and disease.
