BACKGROUND OF THE INVENTION

The present invention relates to magnetic resonance imaging procedures, and more particularly to systems and methods to measure and/or monitor patient temperature during such procedures to prevent burns.

Magnetic residence imaging (MRI) is used to image a patient's internal organs, tissue and in some cases bone. During an MRI, radio-frequency (RF) energy is transmitted through the patient. It has been discovered that RF energy absorption by the patient, implanted or nearby medical devices, and/or MRI ground loops, routinely lead to heating of the patient's skin surfaces in localized or widespread areas. In some cases, the heating leads to RF burns on the patients. Those burns can be first, second or third degree burns in extreme cases.

There are several reports indicating that the limbs or body parts of MRI burn patients were in direct contact with RF body coils or other RF transmitting coils of the MRI equipment. In other cases, it is suspected that the patient contacted an exterior conductive element, such as clothing, or other parts of the MRI equipment. In further MRI burn cases, it is suspected that there was skin-to-skin contact points, caused by the patient placing their thumbs on their thighs, midsection or other areas where RF energy is concentrated during an MR scan.

According to another report, a Joint Commission Sentinel Event Alert, which cited the Manufacture and User Facility Device Experience database of the FDA, “70% of MRI complications are related to thermal burns. ‘The single most common and adverse event in the MRI environment reported to the FDA is that of MRI burns,’ says Emanuel Kanal, MD, FACR, FISMRM, AANG of the University of Pittsburgh Medical Center in Pennsylvania.” Steere, Anna,Battling Burns in the MR, www.healthimaging.com, Sep. 11, 2014. This report also recognized that there are multiple causes of MRI burns. For example, RF energy might not deposit uniformly throughout the patient's body. In some cases, blood flow can redistribute the RF energy resulting in non-uniform, in vivo temperatures. Certain in vivo regions can become more heated than others, and temperatures increase thereby causing RF burns.

Thus, there remains room for improvement in the field of reducing burns to patients undergoing MRI procedures.

SUMMARY OF THE INVENTION

A system and method that utilizes a thermal imaging device to measure and monitor a patient's temperature during an MRI procedure to prevent adverse events, such as burns on the patient's skin surface, are provided.

In one embodiment, the system includes an MRI equipment barrel to provide an MRI image of a patient, and an infrared camera to image the patient separately from the MRI image. The infrared camera includes one or more adjustable parameters. The adjustable parameters can include at least one of an adjustable field of view, an adjustable lens tilt angle, and an adjustable viewing angle. The system further includes a processor that monitors the surface and/or subdermal temperature of the patient based on the output of the infrared camera.

In another embodiment, the processor controls the tilt angle of the infrared camera lens. Controlling the tilt angle of the infrared camera lens includes tilting the optical axis of the camera lens. Stated somewhat differently, controlling the tilt angle of the infrared camera lens includes rotation of a lens plane relative to an image plane. Controlling the tilt angle of the infrared camera lens can improve infrared image acquisition within the barrel.

In yet another embodiment, the processor controls at least one of the field of view of the infrared camera and the viewing angle of the camera during MRI imaging of the patient. In still another embodiment, the system can include a patient gown formed of an infrared transmissive material that provides visual concealment for the patient. The gown, in turn, facilitates thermal monitoring of the patient's skin surface, yet still provides the patient some privacy. The infrared transmissive material can include a polymer, for example polypropylene, polyethylene, and combinations of the same. The infrared transmissive material can include microperforations to provide breathability in some embodiments.

In even another embodiment, the infrared camera can be positioned outside of an MRI magnetic field to minimize electrical interference to or from the infrared camera. Such placement also can minimize the noise detected by the infrared camera, thus providing more detailed, accurate temperature scanning of the patient's skin surface. To further minimize electromagnetic interference, data cables and power cables can include shielding. The data cables and the power cables can additionally include a low pass filter to attenuate noise which might otherwise interfere with MRI imaging. Interference or noise from the infrared camera can also be reduced by enclosing the infrared camera in a Faraday cage. The Faraday cage can include an enclosure of conductive material, for example aluminum, to minimize degradation of the MRI image due to infrared camera electromagnetic radiation.

In a further embodiment, a method of performing an MRI without burning a patient is provided. The method generally includes positioning an infrared camera in a plane generally parallel with the central axis of an MRI barrel. The method further includes monitoring, using the infrared camera, the temperature of the patient's skin and optionally subdermal temperatures during MRI imaging, and altering, during the MRI imaging, at least one of the camera field of view, the camera lens tilt angle, and the camera viewing angle to scan the patient substantially from head to toe within the MRI barrel. The method further includes correlating surface temperatures with internal body temperatures during MRI imaging, and substantially in real time.

In still a further embodiment, the camera field of view, the camera lens tilt angle, and/or the camera viewing angle are further varied in response to a detection of a localized hot spot on the patient. The MRI is paused or terminated in response to the temperature of the patient's body exceeding a threshold temperature associated with possible RF burns. The method can further include donning the patient with a privacy gown that allows infrared wavelengths to pass therethrough, while also providing visual concealment for the patient's body. The privacy gown can be formed of a polymer, for example polyethylene or polypropylene, optionally having micro-perforations formed therein.

The system and method of the current embodiments therefore provide improved detection of RF burns during MRI imaging, including wide-area scans and small-area scans of adult patients, adolescent patients, and pediatric patients. By detecting an increase in skin surface temperature and/or subdermal temperatures of the patient with thermal imaging, the current embodiments can reduce the incidence of RF burns while maintain patient privacy and not otherwise interfering with MRI procedures.

These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.

Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.

