Magnetic Resonance Imaging of the Elbow - Essay Example

SPECIALISED NURSING Name: Course: Professor: Institution affiliation April 11, 2012. Qs 1. Elbow is basically a hinge joint which is made up of radius, humerus and ulna bones. The stability of the elbow is primarily given by the ligaments of ulnar collateral on the inside part of the elbow. Elbow joint is found at the place where all the three bones of the elbow meet. Humerus forms the upper part of the joint and it is the one that is normally felt at the sides of the elbow. Ulna is on the inside part and it is cup shapes which allows articulation with the humerus. Radius is he smaller bone and it is normally on the outside part of the joint (Bland & Rudolfer, 2003, p. 131). The radius has a round head and it is cup shaped which allows moving round the humerus. The elbow has three joints. One that is formed between the humerus and ulna (humeroulnar) and it allows us to bend and straighten our elbows. The other joint is between humerus and radius (humeroradial) and allows extension and flexion of the hand. Another one is proximal/pronation joint that is between ulna and radius. There are three types of ligaments that support the elbow. One is the medial collateral ligaments. This has two triangular bands the anterior and the posterior. These originate from medial epicondyle and go over the elbow joint on the inside part. Lateral collateral ligament which is also known as radial collateral is narrow and short. It passes to the annular ligament from the lateral epicondlye base. Annular ligament is made of fibers that cover the top of radius and it maintains contact between the humerus and the radius (Kathryn &Stevens, 2010, p. 69). Elbow has large muscles which allow extension; flexions as well as supination. There are main muscles which are mostly the ones that get injured. These include biceps brachii which arises from the shoulder blade and they extend down to the arm, they cross the elbow joint and then join the radius. Its main purpose is to flex the elbow and supinate the forearm. Others include triceps brachii, brachialis, brachioradialis, and pronator teres (Carmichael, 2009, p. 99) Qs.2 The best position to place a patient for elbow MRI is the supine position. The arms of the patient should be on the sides and the elbow together with the forearm should be supinated. This is a good position as it reduces the rotation of proximal radial ulnar joint and the forearm. This is in relation to capitellum of distal humerus. Again this is a good position as it allows extensor tendons, medial and lateral ligaments to be viewed in a single coronal plane. Placing the patient obliquely against the bore of the magnet is also a good position for such viewing but it can be limited depending on the size of the patient. Auto shimming might be necessary especially for fat suppression sequences as the region of interest is near the periphery Qs 3 In elbow MRI a number of artifacts can be encountered. Examples include intravascular signal void which is caused by effects of time of flight. The flow of blood can cause turbulent dephasing and echo dephasing. The flow of blood cause movement of hydrogen nuclei and there is change of location between the time that the nuclei get radio frequency pulse and the time the signal that is emitted get to be received (Lu, et.al, 2004, p. 243). This is because the repetition time (RP) is asynchronous with pulsative flow. These artifacts can be reduced by reducing the phase shifts with flow compensation. Saturation pulses can also be used to suppress the blood signal and make them parallel to the slices. Another way of reducing these artifacts is by synchronizing the imaging sequence with heart cycle. Fig 1: Flow artifacts Qs 4. Clinical presentation of Rotator cuff tendonitis Rotator Cuff Calcific Tendonitis is a disease that mostly causes pain in the shoulders. The pain normally radiates to the arm and the neck. In the acute phase it gets irritating by any shoulder movement. In chronic phase the pain in the shoulders becomes common at night. This pain diffuses over the whole shoulder region and therefore becomes difficult to localize. There is tenderness in the affected shoulder and the pain is usually more severe when reaching for something overhead or from the back. Sleeping or pulling something from the affected side worsens the pain. The shoulder also loses its range of motion, and the patient tends to incline in order to keep the shoulder inactive. If the injury is severe one may experience persistent pain and weakness of muscles. Clinically it is easy to differentiate this disease from shoulder bursitis. The presence of calcific deposits on the rotator cuff may not be painful itself. What happens is that pain emanates from other body structures like sub acromial bursa which sometimes may be inflamed. X-ray can be used to view large deposits of calcific. However, ultrasound scans are more effective in identifying the specific location of the deposits (Edelman, 1994, p. 104). (b) The progress of calcific tendonitis can be predicted and normally it resolves gradually without any surgery. It follows the following typical course. • Precalcification Stage: at this stage there are no symptoms that show. The place where the calcification tends to occur usually undergo cellular changes that expose the tissues around to development of calcium deposits..This stage is characterised by thinning of tendon fibers .It is thought to be caused by overuse of the tendons. Calcific Stage: At this stage the cells excrete calcium which later coalesce to form the calcium deposits within the tendons.. From the look the solid is usually soft and appears chalky. In the resting stage, the calcification forms and not painful at this point and can take a long time here. Resorptive stage occurs after the resting stage and it is very painful stage of calcific tendonitis. In this stage the deposits appear like toothpaste. This calcium is derived from the calcium that is circulating within the blood. Postcalcific Stage: This is another painless stage as the calcium deposits disappear and scar tissue appears on the space that the calcific material had occupied. (c) Appearance on X-ray and MRI. In diagnoses of calcific tendonitis the doctor takes the patients history and then examines the patient. X- Ray is done on the shoulder so as to get the image. In case the patient suffers from calcific tendonitis the x- ray will show calcium deposits on the muscles of the rotator cuff. Further tests may be required for evaluation of the rotator cuff and this is when an MRI is necessary.MRI is effective as it can show tendons and muscles on the shoulder that could not be visible with the X-ray (Partain, 2007, p. 100). MRI Qs 5. Carpal bones: These are the eight small bones that are found at the distal ends of radius and ulna and also the five metacarpals. They have different sizes starting from small pisiform to the larger scaphoid. On the surface, the capitates can be felt if the middle metacarpal is already identified and then sliding proximally till a slight depression is felt. This is where the capitates is found and it becomes more prominent if the wrist is flexed. From the capitates all the other bones can be easily identified. Pisiform, hamate and scaphoid can be separately identified in their sections. The bones are in two rows and each row has four bones. Ganglion is the main cause of palpable mass in the wrist. It mostly affects young women. In the population of the affected patients approximately 10% of them have a history of trauma. Hippocrates described Ganglion as knots of tissue that contain mucoid flesh. Histologically, ganglions contain mucinous material and have a capsule with thin connective tissue with no true synovial lining. Histologically, synovial cysts that have synovial lining can be distinguished from ganglion but on imaging they are in distinguishable (Brief & Brief, 2000, p. 71). This is why the terms synovial cysts and ganglion are used interchangeably. Ganglia aetiology is unclear as it may be a synovial herniation or even coalescence of degenerative cysts that originate from tendon sheath or bursae. On MRI, it is seen as a unilocular or even multilocular fluid mass that is that is adjacent to the tendon sheath or a joint. Small effusion may be simulated by small cysts but paucity of the fluid gives the clue of diagnoses. A typical ganglion have low signal on T1 weighed images and a high signal on T2 weighed images. Haemorrhage or proteinous content can cause appearance of lesions that are hyper intense on T1 weighed images (The & Whiteley, 2007, p. 144). (a) Carpal tunnel syndrome Carpal tunnel syndrome is the complexity of symptoms that is as a result of median nerve compression as it crosses carpal tunnel. The main symptoms are paresthesia, pain and also weakness in the median nerve. The most common monoeuropathy in clinical practice is CTS. This disorder affects millions of Americans. Intrinsic swelling causes symptoms to worsen and they can be very frustrating as the patient is hindered from doing their work (poustchi et.al, 2001, p. 211). On MRI a patient with carpal tunnel syndrome shows a bowed flexor retinaculum and inflamed synovium. On T1 weighed images the tendon sheath show low signal intensity and on T2 weighed images there is increased signal intensity. There is also short tau inversion recovery sequence. Other changes observed in the median nerve include: Diffuse swelling of the median nerve that may be visible at the pisiform level (Concannon, 2000, p 153). Flattening of the median nerve is also seen and palmar bowing of the flexor retinaculum.MRI can also be very helpful in diagnosing lesions that occupy space like ganglion cysts and hemangiomas  Bibliography: Bland JD, & Rudolfer SM 2003, “Clinical surveillance of carpal tunnel syndrome in two areas of the United Kingdom, 1991-2001.” J Neurol Neurosurg Psychiatry vol; 74:1674. Brief, R & Brief, LP 2000, “Endoscopic carpal tunnel release: report of 146 cases.” Mt Sinai J Med vol 67(4): 274-277. CARMICHAEL, D. W., THOMAS, D. L. & ORDIDGE, R. J 2009 “Reducing ghosting due to k-space discontinuities in fast spin echo (FSE) imaging by a new combination of k-space ordering and parallel imaging.” Journal of Magnetic Resonance, 200, 119-125. EDELMAN, R. R., WIELOPOLSKI, P. & SCHMITT, F 1994, “Echo-planar MR imaging.” Radiology, 192, 600-612 Concannon, MJ, Brownfield, JL.& Puckett, CL 2000, “The incidence of recurrence after endoscopic carpal tunnel release.” Journal of Plast Reconstr Surg.vol 105(5): 1662-1665. Kathryn J. Stevens MB 2010, “Magnetic resonance imaging of the elbow.” Journal of Magnetic Resonance Imaging. Volume 31, Issue 5, pages 1036–1053, Lu, H., Clingman, C., Golay, X., and van Zijl, P.C 2004, “Determining the longitudinal relaxation time (T1) of blood at 3.0 Tesla” Magn Reson Med 52, 679-682. Partain, C 2007, “Focus on MR safety.” Journal of Magnetic Resonance Imaging 26, 1175-1176 POUSTCHI-AMIN, M., MIROWITZ, S. A., BROWN, J. J., MCKINSTRY, R. C. & LI, T 2001, Principles and Applications of Echo-planar Imaging: A Review for the General Radiologist1” Radiographics, 21, 767-779. The, J & Whiteley, G 2007, “MRI of soft tissue masses of the hand and wrist.” The British Journal of Radiology.vol 14 No 6 Read More