Comparison of the Right-to-left Shunt Test by Transcranial Doppler Based on the Addition of Blood and Patient Posture

Using transcranial doppler ultrasonography (TCD) to measure the presence or absence of abnormalities in patent foramen ovale (PFO) is more effective than transesophageal echocardiography (TEE) because it is simple, inexpensive, and non-invasive.Thus, it can be a good alternative test in cases where it is difficult to perform TEE or in groups at a high risk of complications.Therefore, in this study, we sought to assist in arriving at a diagnosis by suggesting an appropriate method through the comparison of empirical results according to the presence or absence of blood use and varying patient posture.The results were compared depending on the patient's posture and whether blood was used.Patients in whom both middle cerebral arteries were observed were targeted.In cases where the temporal window was defective, it was replaced with basilar artery and compared.There were higher positivity rate and accuracy for sitting position using valsalva maneuver (VM) than for Resting and supine position using VM.Therefore, if it is possible to perform a sitting position using VM with a mixture of blood, it would be a good idea to perform it.