Comparing Contrast Transcranial Doppler Ultrasonography With Contrast Transthoracic Echocardiography For Detecting Right To Left Shunt In Patients With Patent Foramen Ovale

AIM:To compare the value of contrast transcranial Doppler ultrasonography(c-TCD) with transthoracic contrast echocardiography(c-TTE) for detecting right to left shunt(RLS) in patients with patent foramen ovale(PFO). METHODS:The prospective study was undertaken in 195 patients with PFO who suffered from paradoxical embolism. Both c-TCD and c-TTE were performed for all the patients. 58 patients were further through contrast transesophageal echocardiography(c-TEE). The severity of RLS were semi-quantitatively assessed by scaling the numbers of micro-bubbles( MBs) in the left atrium. 58 cases of patients had been checked with c-TEE who gave two kinds of test and at least one was negative. Made c-TEE as the reference standard,we analyze the results of c-TCD and c-TTE. RESULTS: c-TTE demonstrated significantly higher sensitivity for detection of RLS than c-TCD(88.2% vs. 75.9%,χ2=10.029,P=0.002). The positive rate of PFO was higher at Valsalva maneuver(VM) than at rest in c-TCD(χ2=115.317,P<0.001)and c-TTE(χ2=127.209,P<0.001). The comparison of semi-quantitative grading derived from c-TCD and c-TTE was also significant different(Wilcoxon signed-ranks test showed Z=12.429,P<0.001). 58 patients had a negative results of c-TCD or c-TTE,undertaken c-TEE examination further. We made c-TEE as the reference standard. The detection rate of c-TCD was significant different(χ2=19.047, P<0.001),but c-TTE and c-TEE had a good consistency(χ2= 1.333, P>0.100). CONCLUSION:c-TTE is more efficacious in the detection of RLS than c-TCD. It can be used as a suitable promotion technique for screening PFO in clinical practice.