A method was developed to create microbubbles efficiently by adding one drop of Horizon® to cold, agitated saline (one-drop method, or ODM) . We evaluated whether the ODM would improve the detection rate of high-intensity transient signals (HITS) in patients with intracardiac right-to-left shunts (RL-S) .
The subjects for the study were 98 patients who underwent transcranial color flow imaging (TC-CFI) between November 1999 and May 2000. These included 46 patients whose RL-S had been confirmed by transesophageal echocardiography. The detection rate of HITS on the bilateral middle cerebral arteries and/or basilar artery using TC-CFI with ODM was compared with that without ODM.
HITS were found in 17 (17.4%) of the 98 patients using TC-CFI without ODM. On the other hand, 25 patients (25.5%) were found to have HITS using TC-CFI with ODM. Among patients documented as having RL-S (47.8%), the ratio of HITS-positive patients was significantly higher when three arteries were examined under ODM than with single-artery examination (73.3% vs.35.5%) .
ODM is a simple and useful method for improving the detection rate of HITS in patients with RL-S.
