What is an MRI quench?

An MRI quench is the dramatic process in which a magnet in the MRI system loses its superconductivity and liquid helium is converted into gas. This process has a profound effect on the MRI and requires immediate action.

An MRI quench occurs when the magnet of an MRI loses its superconductivity due to an increase in temperature. This leads to a sudden conversion of liquid helium into gas, which is safely discharged. Quenches can be triggered intentionally or unintentionally.

In this article, you will find out exactly what an MRI quench is and what factors can lead to it. We also explain what types of quenches exist, what happens during a quench and how to best prepare for such events.

What happens during an MRI quench? A look at the process

An MRI quench is a critical process in an MRI system that causes the magnetic field to be lost due to an increase in temperature. This converts liquid helium into gas, which leads to a sudden increase in pressure and can put the system out of operation.

This process requires quick and precise action to minimize potential damage and safety risks.

In this article, you will gain a detailed insight into the process of an MRI quench and the possible causes that can lead to such an incident. We explain how the quench works in practice, what types of quenches there are and how professionals should react to them. If you want to learn more about the effects and risks of an MRI quench, you’ve come to the right place.

1 What is an MRI quench?

An MRI quench occurs when a magnet loses its superconductivity and the liquid helium is quickly converted into gas. This leads to a sudden and dramatic reduction in the magnetic field.

An MRI quench is a complex physical process that is triggered by increasing the temperature in the magnet. Normally, the magnetic coils of an MRI system are kept at extremely low temperatures with liquid helium in order to maintain superconductivity.

However, if the temperature rises too much, the coils lose their ability to conduct the current without resistance, which leads to a drastic increase in temperature and therefore pressure. This increase in pressure causes the liquid helium to vaporize and escape as a gas.

The gas must be discharged safely, otherwise the sudden increase in pressure can have dangerous consequences for the environment and the appliance itself. In some cases, this process may be triggered deliberately, for example in an emergency, while in other cases it may be caused by a malfunction or leakage.

Further information on quenches can be found here.

2. function of an MRI quench

An MRI quench occurs when the magnetic coils lose their superconductivity and the magnetism is greatly reduced as a result. This occurs due to a rise in temperature, which increases the resistance in the coils.

The magnetic coils in the MRI are made of superconducting material, which requires extremely low temperatures in order to work without resistance. These low temperatures are achieved using liquid helium.

However, when the temperature rises, the material loses its superconductivity and resistance is created. This resistance generates heat, which causes the liquid helium to vaporize.

The resulting gas pressure is safely discharged via a quench valve to relieve the system.

3. types of MRI quenches

There are different types of MRI quenches, each with different triggers and effects. These quenches can be planned, emergency or unplanned, depending on the specific circumstances in the MRI area.

3.1 Planned quenches

Scheduled quenches are used when a solenoid needs to be temporarily shut down, for example during maintenance work or when a solenoid is decommissioned. These quenches are carried out under strictly controlled conditions in order to shut down the system safely and save costs.

This involves deliberately stopping the cooling of the magnet, which results in a controlled conversion of liquid helium into gas. Planned quenches are generally unproblematic as they are carried out under planned and predictable conditions.

They offer a cost-effective way of temporarily taking the solenoid out of operation without causing permanent damage.

3.2 Emergency quenches

Emergency quenches are triggered if the safety of people or the system is at risk, for example in the event of a fire or metal objects entering the MRI area. In these situations, the magnetic field must be switched off quickly in order to defuse dangerous situations and ensure the safety of patients and staff.

An emergency quench requires quick action – coordinated with other emergency measures such as evacuating the room.

However, these quenches can lead to damage to the solenoid as they are often carried out under unfavorable circumstances. However, they are necessary to save lives and prevent major hazards.

3.3 Unplanned quenches

Unplanned quenches usually occur due to unexpected system faults, such as cooling problems or leaks in the helium circuit. These quenches are unpredictable and can lead to high costs and expensive repairs.

An unplanned quench can often irreparably damage the magnet, resulting in extended downtime and high maintenance costs. An unplanned quench can also affect the quality of the medical diagnosis if the magnet is not ready for use again quickly.

This type of quench represents both a technical and a financial risk, as it is often associated with unexpected problems.

4. what happens in the event of a quench

In the event of an MRI quench, there are various safety aspects that affect both technology and human safety. Specific safety precautions and evacuation measures are required to counteract the dangers of quenches.

4.1 Safety precautions for MRI quenches

Every modern MRI system is equipped with a helium ventilation system that safely discharges the escaping gas to the outside. This prevents the gas from accumulating in the room and dangerously reducing the oxygen content.

To monitor this risk, it is essential to have an oxygen monitor in the room that immediately sounds an alarm if the oxygen level is low. Such an alarm automatically triggers the evacuation of the room to ensure the safety of patients and staff.

Many facilities also have an emergency plan with special measures for dealing with quenches.

4.2 Pressure problems and evacuation

If the helium gas in the room escapes and is not removed by the ventilation system, the pressure in the room can rise dangerously. In this case, it will be considerably more difficult to open the door, which could hinder evacuation.

To relieve this increased pressure, the glass pane between the MRI room and the control room is often deliberately broken.

This step helps to regulate the pressure and enables the door to be opened for a safe evacuation. Once the pressure has been released, patients and staff can be quickly evacuated from the room.

5. costs and effects of an MRI quench

An MRI quench has significant financial implications, both in terms of system recovery and loss of helium.

The cost of filling an MRI scanner with helium can be up to around EUR 25,000. In addition, there are often high repair costs if damage occurs to the coils, which can also run into several thousand euros.

Financial impact

The cost of filling an MRI system with liquid helium can be up to approximately EUR 25,000. As helium plays a crucial role in the operation of the system, the financial impact of a quench can be significant.

In addition, damage to the superconducting coils can necessitate repairs costing several thousand euros. The loss of helium and the downtime of the system also contribute to the high costs.

Repair and maintenance

A quench requires not only the refilling of helium, but also an extensive repair of the system to make it functional again.

This requires specialized technicians and can take several days. The repair costs for damaged coils and other system parts can lead to an enormous financial burden in addition to the helium costs.

6 Conclusion: Avoidance and prevention of quenches

Although quenches are rare, they are associated with significant costs and safety risks. Regular maintenance and the implementation of preventive measures are crucial to minimize the risk of a quench and maintain the safe operation of the MRI system.

6.1 Preventive measures

Regular maintenance of the MRI system is essential in order to identify and rectify potential sources of error at an early stage. A functioning helium ventilation system can help to reduce the risk of quenching by safely removing excess helium. Monitoring the temperature and pressure in real time also contributes to prevention and ensures that the system is working under optimal conditions. Targeted training for medical staff and technical specialists can also reduce the risk of human error.

6.2 Importance of safety

A functioning safety concept is necessary in order to be able to react quickly and effectively in the event of a quench. The installation of oxygen monitors and staff training in emergency procedures help to minimize the risk of injury or health hazards. Regular drills and emergency protocols ensure that action can be taken quickly in the event of an emergency to protect both patients and employees.

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