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

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.