The MRI worth more than a thousand words

Arm ache. Close up of businessman hand tired from typingTeam from UC Davis Health System created a protocol allowing acquisition of a wrist motion sequences with use of short MRI scan series – the Active-MRI. The technique, developed by a group of radiologists, medical physicists and orthopaedic surgeons may become a valuable tool in diagnostics of early functional disorders that can underlay further pathologies such as wrist instability.

​Wrist instability may occur when the carpal bones lose their primary arrangement which affects the joint function. The condition is frequently preceded by episodes of injury of the area. The symptoms are abnormal movements and chronic pain, as a result of osteoarthritis. The best prognosis of treatment can be expected in case of early diagnosis, when the less invasive treatment is available.

The wrist movement can be imaged wit use of dynamic computed tomography or fluoroscopy. Those methods, however, can not present soft tissue structure (e.g. ligaments) with such high detail level as the MRI study. The patient’s exposure to the x-ray is also the relevant difference there. On the other hand, the static MRI study is not likely to always image the wrist anatomy abnormalities that may be responsible for symptoms that occur during movement.

Dr Chaudhari, assistant professor at UC Davis underlines, that the major benefit of Active-MRI protocol is imaging the real-time motion wrist with use of broadly available and safe equipment.

The researchers had to deal with certain technical issues to use MRI technology for motion sequences acqiusition. A typical MRI study duration is usually between 30 and 45 minutes with single sequence time for 3 min. in average. Another issue was presence of banding artifacts. A bone movement in the examined area may interfere with magnetic field of the device, causing the undesired signal drop-offs. In result, dark areas may cover examined wrist. The team overcame this limitation, applying dielectric pads, which stabilise magnetic field and move artifacts away from the examined area.

Researchers believe, that the protocol can assist the classic MRI study in early diagnosis of wrist instability.

Written by: Tomasz Roman, Justyna Markowicz, Agnieszka Szymczyk


Source: 1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0084004
2. Chantelot C. Post-traumatic carpal instability. Orthop Traumatol Surg Res. 2014 Feb;100(1S):S45-S53
3. Boutin RD, Buonocore MH, Immerman I, Ashwell Z, Sonico GJ, Szabo RM, Chaudhari AJ. Real-time magnetic resonance imaging (MRI) during active wrist motion–initial observations. PLoS One. 2013 Dec 31;8(12):e84004

Would You like to know more? Watch on MEDtube.net: Causes of the wrist pain – Video Lecture

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