 Hi everybody. Today I am going to talk about MRI soldier imaging protocol. We will have a brief introduction followed by a little bit discussion about the hardware and then detailed discussion about the imaging sequences. Like in any other areas of MSK imaging in soldier also, our motto is to demonstrate anatomy as well as to pick up the pattern. For adequate demonstration of the anatomy, you need to see these structures around the shoulder joints like ligaments, tendons, cartilages, separately well from each other and that is best done by non-fatset images, PD and G1 weighted images. In these sequences, fat has a higher signal which helps to enhance the tissue contrast so that the high point in structures like ligaments and the tendons are better seen. On the other hand, fluid sensitive sequences like fat set sequences, fat set T2 and PD sequences show the edema and the fluid well. So, the pathologies are better identified in these sequences. For better quality images, you need a higher SNR that is signal noise ratio and better spatial resolution. These can be achieved by using thinner sequences, using high imaging metrics and increased number of excitations. But problem is, if you employ all of these, then there will be increased imaging time and that might result into increased patient movement and thus the SNR will ultimately be reduced. So, you have to strike a balance between the quality and the timing of your image. Unlike other areas of joint, shoulder is unique because it is close to the chest wall and thus the images can be affected by the respiratory movement. So, if you use a saturation band, then your image quality will be better. Now, little bit about the hardware. You need two image shoulder in 1.5 or 3 Tesla machine. Higher field strength is preferable because it will increase the SNR. You need a dedicated shoulder coil. If you don't have it, then you can image with a surface coil. But a dedicated coil is preferable because it will also improve the SNR. For routine shoulder joint imaging, the patient position is supine with head first imaging. The arms by the side of the body, parallel to the body. Humerus can be neutral or little externally rotated which is preferable. If you externally rotate the humerus more, then it can induce pasm and the resulting movement can reduce the image quality. It is better to immobilize the hand with the help of a sandbag. For special sequences like abduction and external rotation scans, the hands should be placed behind the head. The sequences are usually a combination of PD non-fat set and fat set sequences. I prefer to have a T1 sequence in sagittal plane instead of a PD sequence and you should go through the clinical indication before starting imaging because your choice of sequence might be affected by the clinical indications. For example, if you are dealing with a tumor or an infection, then you need to have fat set T1 sequences in your imaging protocol and also use contrast. The same is true for inflammatory arthropathias. So my preferred imaging protocol is axial PD fat set sequence, coronal oblique PD as well as T2 fat set sequence and sagittal oblique T1 and PD fat set sequence. All the sequences are turbo spin echo sequence. Now I want to stress two things. Firstly, in coronal oblique images, you need to add a T2 weighted sequences that is T2 fat set sequence because of the obliquity of the course of the supraspinatus tendon and it will cause a magic angle effect with resultant increased signal within the tendon. These are evident in low T sequences like the PD sequence and the T1 sequence. So you can have a spuriously high signal in coronal oblique PD sequence or PD fat set sequence. If you add a T2 fat set sequence, then with higher T the magic angle effect will be minimized. Another important thing is about the sagittal oblique sequences. You need to comment about the supraspinatus and the infaspinatus muscle atrophy in your report. So you have to cover up to muscle belly. So you have to go more medially in the sagittal T1 oblique sequences. So routine scanning will start with a 3-pin localizer followed by axial images upon which you will plan your oblique imaging planes. The coronal oblique imaging plane is parallel to the supraspinatus tendon. It is important to note that the even imaging should be parallel to the tendon not the muscle and the sagittal oblique images these are parallel to the glenohumeral joint plane. For axial images it is important to cover a few slices above the AC joint and you should image through the glenohumeral joint to the level of the upper humerus. Now why oblique plane is important? Because it will help you to orient the structures like supraspinatus in such a way that its full length can be seen in at least one or two images in coronal oblique plane. So you can better evaluate the signals within the tendon and it will also minimize the parcel volume effect. The usual slice thickness is between 3 to 4 millimeter preferably with no gap or with minimal gap. The matrix should be at least 256 into 256 that is in frequency and the phase direction. The field of view should be small between 12 to 14 centimeter. We do not need to use 14 centimeter. So you need a total of six sequences or soldering joint imaging. Two in each orthogonal plane one for the anatomy that is PD or T1 and one for the ethnology that is fluid sensitive sequences either PD fat set or T2 fat set sequence. A PD sequence is an intermediate weighted sequence with a low T and high tier. In MSK imaging particularly in solder we have to adjust the TE and the tier values in such a way that we get a better SNR and you can tweak this intermediate weighted sequences with a little bit of higher side T like in 40s or 60s. The higher T in PD sequences will result in increased fluid sensitivity and this will help to differentiate between the tendinosis and the tier. To minimize scan time we use routinely the TSE sequences but it is important to know that this images has inherited blurring and to minimize blurring we have to use less equitent length. If we use longer TE the blurring will be minimal and the higher resolution matrix will also reduce the blurring. Now we have already talked about the routine sequences now some additional sequences like fat set T1 and post-gadolinium fat set sequences when we suspect infection or tumor and also in inflammatory orthopedics to seek the enhancement of the synovium. The T2 GRI sequences are helpful for intralabial degeneration and for calcific tendinosis. For GRI sequences we usually use a still smaller field of view like a 10 centimeter field of view. A marathogram with injection of either saline or gadolinium into the joint is used for specific indications like chronic solder pain with negative routine MR. In post-operative cases with capsulolabial repair recurrent rotator cuff tear and when there is injury to the inferior guino-humeral ligament. And finally abduction and external rotation imaging which is usually done along with MR orthogram. There are very few indications like a post-operative labram evaluation, non-dispressed labral tears particularly pathese tears for anterior or multidirectional instabilities. In this position the anterior band of the IgHL is taut so it is better seen and thus any tear or laxity is better evaluated. And occasionally flap type of under surface tear which may be missed in tauts or presparinatus tendon in usual coronal oblique imaging. It is better seen in this position of course with orthogram images. Another thing is that the type 2 slab pillback injury of the biceps labral complex sometimes can be better demonstrated in ABAR positioning. That's all for today. Thanks for watching this video.