FAI Definition and Discussion

1- Femoroacetabular Impingement (FAI) can be an indication for MRI of the hip. Define and discuss this condition.

2- Discuss coil selection and describe how you would position a patient for MRI of hips.

3- “Tennis Elbow” is a common indication for elbow MRI. Define and discuss this condition.

4- Discuss coil selection and describe how you would position a patient for MRI of an elbow

1. Femoroacetabular Impingement (FAI) can be an indication for MRI of the hip. Define and discuss this condition.

Femoroacetabular Impingement or FAI is said to be a condition where the hip bones are unusually shaped (Owens, 2009). As because of the irregular bones, they do not perfectly fit together and hence, rub against one another. This causes injury to the hip joint.

This picture represents healthy hip; femoral head sets in perfectly into acetabulum; source:

Basically, the hip anatomy is made up of a ball and socket joint. The socket potion is made up of acetabulum, the part of largest pevis bone. The ball is mainly the thighbone or femoral head that is the upper area of femur. A greasy tissue, articluar cartilage cover ups the ball and socket surface. The articluar cartilage creates a low friction and smooth surface, which helps the hip bones to easily move smoothly across one another. The acetabulum is looped by labrum, a strong fibrocartilage. The labrum practically works as a mechanical seal, a tight seal that gives joint stability. 

This picture illustrates comparison among different states of FAI; source: (Hessel, 2014).

In case of femoroacetabular impingement, bone spurs form along the acetabulum or femoral head. The overgrowth of bone causes hip bones to knock against one another and cannot move smoothly (Pun, Kumar & Lane, 2014). Eventually, this condition can give rise to the ripping of labrum and articular cartilage breakdown, which is also termed as osteoarthritis.  

There are mainly three types of FAI, medically termed as cam, pincer and combined impingement.

Cam: In case of cam, the femoral head is malformed and failed to rotate smoothly inside acetabulum. A bulge appears on the boundary of femoral head and this appearance crushes the cartilage insde acetabulum.

Pincer: This type of condition arises because of extension of an extra bone over normal acetabulum rim. This situation can crush labrum beneath the prominent rim of acetabulum.

Combined: In this type of impingement both can and pincer types are visible.

Currently it is quite difficult to statistically present the data of FAI affected individuals. Few people may survive for a longer period of time, actively with FAI and may never face any complications. Nevertheless, while indications develop it generally shows that damage is present to the labrum or cartilage and subsequently the illness is expected to progress. Indications may include limping, stiffness and pain.

FAI takes place as hip bones fail to form usually during childhood. It is considered as the malformation of a pincer or cam bone spur or both the condition together, which causes joint pain and damage.  It is said that when hip bones are abnormally shaped, there will be few options left to avoid this condition. Researchers have seen that athletically active individual may utilize their hip joint more dynamically. They may start to feel the pain prior than those individuals who are not much active. Nevertheless, exercises do not cause FAI.

Types of FAI

FAI affected individuals generally suffer from pain within the groin region, through pain can be sometimes felt towards the exterior part of the hip. Sharp and stabbing sensation of pain may initiate with squatting, twisting and turning but occasionally it is merely a dull sensation.

Impingement test

Initially the physician prefers to check the primary indication by conducting impingement test. During this examination, the knees are brought up to the chest and rotate inwards towards opposite the shoulders. If this rotation created pain in the hip, the result indicates positive signs for impingement test.

Imaging tests include x-rays, MRI and CT scans. MRI is considered as the best imaging test, as this can create better images of flexible tissues. By this test physicians find damages to the articular cartilage and labrum area. To make the image more prominent, dyes are injected into the joint areas. Or else, numbing medicines are also injected into the joints. These medicines give pain relief for certain period of time and confirm that femoroacetabular impingement is a complication.

Treatment includes surgical and non-surgical interventions. Activity changes, physical therapy and non-steroidal anti-inflammatory drugs come under non-surgical interventions. Such as: ibuprofen helps to reduce inflammation and pain.

Incisions to treat FAI; source: (Palmer et al., 2014)

Many femoroacetabular impingement complications are treated with surgical treatment. For example: arthroscopic techniques are performed with little incisions and light instruments. 

According to the American Society for Sports Medicine, surgeries can diminish indications successfully caused by impingement. Correcting this problem can stop further damage to the joints of the hip region (Amssm.org, 2015). Nevertheless, all the damage cannot be corrected with surgeries, particularly if management has been postponed and injury is severe. Therefore, recently, surgeries are considered as the best way to manage painful femoroacetabular impingement.

2. Coil selection

Multipurpose phased array coil; source: (Möller & Reif, 2010)   Shoulder coil; source: (Möller & Reif, 2010).

Characterizing anatomical borders for MRI offers means of verifying the inclusion regions when selecting a proper radiofrequency coil and developing a pulse sequence. Inidivual imaging coil has particular specified view field, which need to be considered by radiographer, while choosing a proper device. Different coils are structured with a typical function in mind, but are commonly adapted in medical imaging purpose of more than one area of the system. Multipurpose phased array coil is probably the best for imaging purpose for joints, like hip and elbow region (Petchprapa, Dunham, Lattanzi & Recht, 2013). Not only that, shoulder coils may also be used for hip joint imaging. MRI of hip joints is considered as the most hopeful and rapidly developing methods of contemporary diagnostics. The doctors can investigate the pathological and structural changes and also evaluate pathophysiological and physico-chemical processes of hip joints all together or as individual structures. For hips, a dedicated phrased array hip coil or phased array cardiac coil or phased array torso coil is good to use. If signal to noise ratio is not satisfactory with torso coil, then using a flex wrap coil is always recommendable (Orbach et al., 2006). The view field needs to be adequate to resolve acetabular roof and articular cartilage of femoral head. In case an extra Matrix or NEX is needed for proper SNR on 3small field of view (FOV) sequences through affected if, then the radiographer should perform so, even though this process adds additional times. The coronal stir needs to be a rapid sequence; the slice thickness and resolution need to be accustomed to save some time. It is uncomfortable for a patient if the examination duration increases. Therefore, the capacity to combine parts for multi-region imaging amplifies the efficacy of each coil modules, and this makes the imaging technique of different pathologies or medical indications less burdensome for the radiographers and reduces the time of examinations.

FAI Progression

Supine position; source: (Rengle et al., 2009)               Decubitus position; source: (Rengle et al., 2009)

A radiologist may position a patient for in certain postures and coil will be used around the region of interest. This should be exact, as it provides doctors with an outstanding examination. Sometimes the radiographers may ask a patient to lie in a particular position which is not comfortable for him/her. If a patient is feeling complications with a particular position requested, then the patient should convey the same to the radiographer prior starting the assessment. The radiographer may adjust the patient to a comfortable position, so that he/she can examine the patient properly. A proper position of a patient for hip MRI should be the following: supine-feet first (Bright, 2009). This position is helpful to wrap or tape the feet together to diminish the leg movement. If coils are appropriate for body’s imaging, they may be applied when patient illness put limitations on conventional positioning. For example: if a patient is incapable to lying in supine position, the patient may better bear the technique when asked to lie in a decubitus position and examined applying a coil.

3. Tennis elbow is said to be a condition where the external parts of elbows become tender and painful. Tennis elbow is also termed as lateral epicondylitis. The external parts of elbows are known as lateral epicondyle. In this condition a chronic or acute inflammation may take place in the joint tendons within the muscles of forearms on the external part of the elbows (Mellor, 2003). The tendons and forearm muscles become injured from over repetitive use, which means repeating the same motions frequently. The tenderness, pain and inflammation on the external parts of elbows are because of the over repetitive motions of the forearm. 

Tennis elbow; source: (Jones, 2009)

As it is mentioned earlier, tennis elbow is caused by overuse injury. It happens when the tendons and muscles of the forearms are strained because of strenuous or repetitive activity. Not only this, this condition may take place after knocking or banging the elbows. If the tendons or muscles are stressed, tiny inflammation and tars can develop near to the bony lump on the exterior region of the elbows. Activities that can cause tennis elbow include: playing squash, badminton or tennis; throwing sports, like: discus or javelin; application of shears while gardening; application of roller or paintbrush while decorating; bricklaying or plumbing; activities, which includes wrist and hand movements, like: typing or using scissors and other works that include repeated elbow movement, like: playing violin. Researchers have shown that the extensor carpi radialis brevis muscle contributes greatly in this condition (Sasaki et al., 2011). Trauma, for example: direct blows to epicondyle, sudden forceful extension of pull are responsible mainly for these injuries. Playing tennis in a wrong way may initiate the condition of tennis elbow early, as shock is acquired while a player misses a hit. Mostly individual of 30-50years of age are affected with tennis elbow, through anybody can get affected with tennis elbow, if they have the possible risk factors. Macroscopic and microscopic tears between the periosteum area of lateral humeral epicondyle and the extensor tendon are the main pathological changes, occur during this condition. Radial nerves are significantly associated with this condition. In this condition radial nerves constrictions may take place by sticking to the short extensor muscle and radiohumeral joint of the wrist.  Calcification of bicipital tendinitis, rotator cuff and carpal tunnel syndrome can increase the possibility of tennis elbow.

Causes of FAI

Pain location in lateral epicondylitis; source:

In this case, generally pain slowly increases around the exterior part of the elbow and very less it is seen that pain develops all of a sudden. Pain is worst while squeezing any object, shaking hands, moving wrist with force, such as: using tools, lifting, opening jars, application of fork, knife or toothbrush. It weakens the grip strengths.

Doctor generally considers different factors while making an analysis. These include how the indications developed, work-related risk factors and sports participation. Imaging tests include x-rays, MRI and EMG. Electormyography or EMG is performed to exclude nerve compression. If a physician assumed that he pain is associated with neck problem, an MRI scan is recommended to check for a possibility of arthritis or herniated disk in the neck. Both these conditions may produce pain in the arm (Chiang, Hsieh & Lew, 2012). X-ray is generally performed to exclude the condition of elbow arthritis.

Non-surgical: steroid injections can be administered in this condition, for example: cortisone is very efficient as anti-inflammatory drugs. However, another option is extracorporeal shock wave therapy, where it sends sound waves towards the elbow and creates microtrauma, which induce the system’s natural healing pathways (Hughes, 2010). This technique is still in its infancy. Physical therapy includes exercises for improvingthe muscle strength of forearms. Therapist may perform ice massage, ultrasound or other associated muscle stimulating techniques to develop muscle healing.

Surgical: if non-surgical treatments do not respond well, then a physician mostly recommend a patient for surgical treatment. This includes open surgery and arthroscopic surgery. Open surgery is considered as the most common approach. This includes performing an incision over elbow. After surgical treatment arm may be temporarily immobilized with splint. After a week the splint and sutures are removed (Larsen, 2012). Researchers have suggested that, with surgical invention various complications may have raised, and almost 80-95% patients showed successful response with non-surgical therapies.

4.

5-inch wraparound coil; A-represents General Electrical flex receive-only coil and B-represents elbow position; source: (Kaplan & Potter, 2004).

The attainment of standard MRI images of elbow is tough by various factors, which includes complication in patient positioning, lack of dedicated elbow coils and lower signal to noise ratio at the off-center magnate. Elbow imaging can be taken side-wise or by placing the patient in superman position. 5-inch wraparound coil is good for imaging elbow (Teh, 2007). This type of coils are versatile and help in visualization of articulation, comprising distal biceps tendon attachment to radial tuberosity, containing different variety of elbow sizes. Images of elbows, which are obtained in flexed position, necessitate the application of surface coils.

Picture A, B and C shows patient positions for elbow imaging; source: (Subramanya & Herald, 2014).

Picture A shows elbow phased array coils and B shows larger phased array coils; source: (Subramanya & Herald, 2014).

Elbows are complicated joints and commonly injured areas. Assessment of the elbows by MRI is considered as an important option to medical examination. In case of elbow imaging, it should be carried out in three planes. This is because certain structures are finely observed in a particular plane that means:  ligaments in coronal, bicep tendons in sagittal and nerves in axial plane. The sequence choice differs by organization and need to include proton density weight sequences and non-fat saturate T1or tiny tau inversion improvement sequences that are crucial for potential bone injury evaluation. Patient positioning is considered as the most important part with MRI. The available coil types, support limitations, size of the patient and medical status may contribute to the suboptimal assessments, especially within the upper extremities. The incarcerating nature of mainly high field MRIs, excluding extremity and open systems, diminishes positioning options, typically for obese patients. Imaging can be achieved with lower field strength and the currently applicable field strengths for elbow MRIs are 1.5T units and 3.0T units. Patients are mostly placed in supine position with extended elbow, supinated forearm and arm at the sides. Contralateral arm is sometimes placed above head to develop centering of elbow (Seay, Hasselquist & Bensel, 2011). But in this type of position, patients sometimes feel uncomfortable. Hence, a dictated circumferential coil can be applied in this situation. Larger phased array coil is preferable for analyzing larger regions, for example: elbow alone or elbow with forearm.

References

Amssm.org,. (2015). American medical society for sports medicine – AMSSM. Retrieved 22 March 2015, from https://www.amssm.org/

Bright, A. (2009). Planning and Positioning in MRI. London: Elsevier Health Sciences APAC.

Chiang, Y., Hsieh, S., & Lew, H. (2012). The Role of Ultrasonography in the Differential Diagnosis and Treatment of Tennis Elbow. American Journal Of Physical Medicine & Rehabilitation, 91(1), 94-95. doi:10.1097/phm.0b013e31823caf7f

Hessel, J. (2014). Femoroacetabular Impingement in Athletes. Orthopaedic Nursing, 33(3), 137-139. doi:10.1097/nor.0000000000000045

Hughes, N. (2010). The effects of elbow manipulation combined with dry needling compared to manipulation combined with cross friction in the treatment of lateral epicondylitis.

Jones, V. (2009). Physiotherapy in the management of tennis elbow: a review. Shoulder & Elbow, 1(2), 108-113. doi:10.1111/j.1758-5740.2009.00023.x

Kaplan, L., & Potter, H. (2004). MR imaging of ligament injuries to the elbow. Magnetic Resonance Imaging Clinics Of North America, 12(2), 221-232. doi:10.1016/j.mric.2004.02.006

Larsen, L. (2012). Sports injuries sourcebook. Detroit, MI: Omnigraphics.

Mellor, S. (2003). Treatment of tennis elbow: the evidence. BMJ, 327(7410), 330-330. doi:10.1136/bmj.327.7410.330

Möller, T., & Reif, E. (2010). MRI parameters and positioning. Stuttgart: Thieme.

Orbach, D., Wu, C., Law, M., Babb, J., Lee, R., Padua, A., & Knopp, E. (2006). Comparing real-world advantages for the clinical neuroradiologist between a high field (3 T), a phased array (1.5 T) vs. a single-channel 1.5-T MR system. Journal Of Magnetic Resonance Imaging, 24(1), 16-24. doi:10.1002/jmri.20612

Owens, B. (2009). Femoroacetabular Impingement. Orthopedics, 32(3), 158-158. doi:10.3928/01477447-20090301-22

Palmer, A., Ayyar-Gupta, V., Dutton, S., Rombach, I., Cooper, C., & Pollard, T. et al. (2014). Protocol for the Femoroacetabular Impingement Trial (FAIT): a multi-centre randomised controlled trial comparing surgical and non-surgical management of femoroacetabular impingement. Bone And Joint Research, 3(11), 321-327. doi:10.1302/2046-3758.311.2000336

Petchprapa, C., Dunham, K., Lattanzi, R., & Recht, M. (2013). Demystifying Radial Imaging of the Hip. Radiographics, 33(3), E97-E112. doi:10.1148/rg.333125030

Pun, S., Kumar, D., & Lane, N. (2014). Review: Femoroacetabular Impingement. Arthritis & Rheumatology, 67(1), 17-27. doi:10.1002/art.38887

Rengle, A., Armenean, M., Bolbos, R., Goebel, J., Pinzano-Watrin, A., & Saint-Jalmes, H. et al. (2009). A Dedicated Two-Channel Phased-Array Receiver Coil for High-Resolution MRI of the Rat Knee Cartilage at 7 T. IEEE Transactions On Biomedical Engineering, 56(12), 2891-2897. doi:10.1109/tbme.2008.2006015

Sasaki, K., Tamakawa, M., Onda, K., Iba, K., Sonoda, T., Yamashita, T., & Wada, T. (2011). The detection of the capsular tear at the undersurface of the extensor carpi radialis brevis tendon in chronic tennis elbow: the value of magnetic resonance imaging and computed tomography arthrography. Journal Of Shoulder And Elbow Surgery, 20(3), 420-425. doi:10.1016/j.jse.2010.12.002

Seay, J., Hasselquist, L., & Bensel, C. (2011). Carrying a rifle with both hands affects upper body transverse plane kinematics and pelvis–trunk coordination. Ergonomics, 54(2), 187-196. doi:10.1080/00140139.2010.538726

Subramanya, S., & Herald, J. (2014). Reverse Shoulder Arthroplasty With Patient-specific Glenoid Implant Positioning Guides. Techniques In Shoulder & Elbow Surgery, 15(4), 122-129. doi:10.1097/bte.0000000000000035

Teh, J. (2007). Imaging of the elbow. Imaging, 19(3), 220-233. doi:10.1259/imaging/56624048