The clinical gold standard for cardiac gating is applying an electrocardiogram.
However, the cardiac synchronization with ECG is challenging at high fields due to the magneto hydrodynamic effect (MHD), what causes problems in workflow in clinical routine.
We have developed smart-sync, a Doppler Ultrasound gating device, that is easy and fast to apply and not disturbed by the magnetic field.
The core of smart-sync is the battery powered and wirelessly connected Sensor Box. It is used together with an adult transducer that is specifically designed for an easy and fast placement to detect the adult heartbeat during MRI examinations.
A unique algorithm is applied on the Doppler ultrasound signal of the adult heart that allows precise gating for uncompromised image quality. smart-sync can be integrated into any MRI system with the included Connector Box.
specifically designed for an easy and fast placement to detect the adult heartbeat
To optimize the workflow in clinics, we have developed a specifically adult transducer that allows an easy and fast placement to detect the adult heartbeat without the use of uncomfortable electrodes.
The transducer is placed comfortably on the chest above the patient's heart. Once the heart is located the transducer is fixed with a belt.
smart-sync creates a gating signal that is sent wirelessly to the MRI.
In contrast to ECG the Doppler Ultrasound Signal does not reflect the electrical activation. Due to the Doppler effect the moments of real cardiac motion can be measured. This are exactly the time points during the cardiac cycle that are needed for gating as we want to freeze the motion in time.
Systolic Gating similar to the ECG
To enable a gating signal to the time point of maximum cardiac motion smart-sync uses the atrial contraction (A-wave) that appears just before the R-wave of the ECG. This enables smart-sync to be used in the normal workflow without changes.
For prospective gated cardiac sequences the gating signal should be in diastole. With the measurement of the E-wave smart-sync features a gating signal to the beginning of diastole.
Measurements at 7T gated with Doppler Ultrasound
Karen Markenroth Bloch, Fabian Kording, Johannes Töger
1. Lund University, Bioimaging Center, Lund Sweden
2. Univ. Medical Center Hamburg-Eppendorf, Germany
3. northh medical GmbH, Hamburg, Germany
4. Lund University, Skane University Hospital, Sweden
K. Markenroth Bloch, National Swedish 7T facility, Lund University Bioimaging Center