Saline versus Saline with Blood as a Contrast Agent for Right-to-left Shunt Diagnosis by Transcranial Doppler: Is There a Significant Difference?

ABSTRACT BACKGROUND AND PURPOSE Agitated saline solution (AS) is the contrast agent (CA) of choice for the diagnosis of right‐to‐left shunt (RLS). The aim of this study was to compare AS to AS with blood (ASb) in the diagnosis and quantification of RLS by contrast‐enhanced transcranial Doppler (cTCD). METHODS Forty‐two patients were evaluated for RLS in both of the middle cerebral arteries (MCA) by cTCD. Both AS and ASb were used as CAs while the patient breathed spontaneously and during two different moments of a Valsalva maneuver. Embolus track (ET) counts were obtained from each MCA (MCA analysis) and from each patient (patient analysis). RESULTS In the MCA analysis, at least one ET was identified in 109 (43.2%) of the AS tests and 136 (54%) of the ASb tests (P= .016). The ET counts were higher with ASb (78.0 ± 117.6) than with AS alone (46.9 ± 66.7; P= .01). In the patient analysis, at least one ET was identified in 62 (49.2%) of the AS tests and 77 (61.1%) of the ASb tests (P= .057). Similar ET counts were generated with both CA solutions. CONCLUSIONS These findings support the inclusion of ASb as an option for RLS diagnosis in selected patients.