Comparison of Two Contrast Agents for Right-to-Left Shunt Diagnosis with Contrast-Enhanced Transcranial Doppler

Abstract

We compared two contrast agents, agitated saline and agitated saline with blood, with respect to their efficacy in the diagnosis of right-to-left shunt with contrast-enhanced transcranial Doppler. Three hundred thirty Chinese patients underwent examinations with one of four different methods in random order: (i) 9 mL agitated saline solution with 1 mL air without the Valsalva maneuver (ASwoVM); (ii) 9 mL agitated saline solution with 1 mL air with the Valsalva maneuver (ASwVM); (iii) 9 mL agitated saline solution, 1 mL air and a drop of the patient's blood without the Valsalva maneuver (ASbwoVM); and (iv) 9 mL agitated saline solution, 1 mL air and a drop of the patient's blood, with the Valsalva maneuver (ASbwVM). Rates of detection were 11.5%, 17.9%, 16.7% and 23.6% for the ASwoVM, ASwVM, ASbwoVM, and ASbwVM examinations, respectively. The embolus track numbers for these examinations were 4.0 ± 1.83, 11.5 ± 6.2, 10.5 ± 4.9 and 33.7 ± 14.9, respectively. There were significant differences between the four groups (all comparisons, p < 0.001). For contrast-enhanced transcranial Doppler examinations, the agitated saline/blood agent yielded better rates of diagnosis of right to-left shunt than did the agitated saline alone.