Usefulness of Measurement of Circulation Time Using MgSO4: Correlation with Time-Density Curve Using Electron Beam Computed Tomography

ABSTRACT

PURPOSE: To determine the usefulness of MgSO 4 for measuring the systemic circulation time. Material and Methods: Systemic circulation time, defined as elapsed time from the injection of MgSO 4 solution to the point of pharyngeal burning sensation, was measured in 63 volunteers. MgSO 4 was injected into a superficial vein of an upper extremity. Using dynamic electron beam computed tomography at the level of the abdominal aorta and celiac axis, a timeintensity curve was plotted, and for these two locations, maximal enhancement time was compared. RESULTS: For 60 of the 63 subjects, both systemic circulation time and maximal enhancement time were determined. Average systemic circulation time was 17.4 (SD 3.6) secs. and average maximal enhancement times at the level of the abdominal aorta and celiac axis were 17.5 (SD 3.0) secs. and 18.5 (SD 3.2)secs., respectively. Correlation coefficients between systemic circulation time and maximal enhancement time for the abdominal aorta and celiac axis were 0.73 (p<0.01) and 0.73 (p<0.05) respectively. CONCLUSION: The systemic circulation time demonstrated by MgSO 4 injection and maximal enhancement time for the abdominal aorta showed significant correlation. Thus, to determine the appropriate scanning time in contrast-enhanced radiological studies, MgSO 4 can be used instead of a test bolus study.