Sources and Impacts

MRI artifacts are generated by multiple sources including:

  • MR scan gradients
  • Magneto hydrodynamic (MHD) effect
  • Heart motion
  • Blood-flow
  • Other body & organ motion

Artifacts impair image quality causing blurring of the imaged object resulting in misleading pathologies and need for rescans.

They also obstruct diagnostic-quality ECG monitoring for heart-rate variability, arrhythmia, PVC, ischemia, etc.) during MRI exams, resulting in risks to patient safety.

MHD effect (see image below), is considered a prime artifact because of its corrupting affect on ECG ST segments

Magnetic Field Strength and MHD

MHD Effect is the induction of a voltage in a conductive fluid, flowing through a magnetic field, . . .  a well known phenomenon in fluid mechanics called the magneto-hydrodynamic (MHD) effect.

As soon as a patient is placed in the MR bore, and prior to scanning, they are under the influence of the MHD effect. This causes an amplitude increase in the T-wave of the EKG, which is frequently confused with the R-wave or standard "trigger point". 

As magnet strengths increase, so do artifact impacts, in particular MHD.

Magnet Strength:  The ECG image (right) shows an ECG taken outside the magnet ("0 T"). 

At 1.5 T, the MHD impact shows an alteration of the T-wave and distortion of the T-Q wave, which becomes much stronger at 3.0 T.  

ACDx Technology Benefits

Artifact Reduction

By cleanly separating signals obtained during MRI procedures, ACDx can:

improve gating and triggering accuracy to produce reliably clearer images, even during cardiac events.

Reduced exam times

Clearer images mean fewer rescans,  shorter exam times and increased MRI throughput.

Diagnostic-quality ECG monitoring

Full, real-time diagnostic-quality ECG monitoring means, during procedures, you can reliably monitor your patient's heart-rate & heart-rate variability, PVCs, arrhythmic and ischemic occurrences with early-warning of any ECG complications.

Blood-flow monitoring

With ACDx, you will be able to monitor your patient's blood-flow while scanning. 

Enhanced Decision-Support

Synchronized image and physiologic data reports will be available on a pay-per-click basis, providing greater evaluation intelligence.

Key to new benefits

We anticipate new clinical and research applications to emerge from ACDx capabilities, enabling users to go beyond current Gating & Monitoring limitations.