UCSD Musculoskeletal Radiology bonepit.com MRI Bone Protocols

Musculoskeletal MR Protocols

UCSD Medical Center/Thornton Hospital

University of California, San Diego

Instructions for Musculoskeletal Fellows:

          All MR requests must be reviewed and a protocol provided in advance.  Go over to the MR facility each morning to review the requests for the next day and specify a protocol for the examination.  The requests will be at the front desk.  If there are x-rays or other imaging studies available, read the reports on IDXRAD or review them before you protocol the cases.

            Attached are our "routine" protocols, which will cover most clinical indications.  Try to follow the routine protocol whenever possible.  Special circumstances may require additional sequences or sequence substitutions.  Be very specific when you change the routine protocol!  Limit the number of sequences to the minimum necessary to answer the clinical question.  If you have questions, discuss the case with the attending radiologist. 

            Monitor the daytime cases whenever possible to make sure we have addressed the clinical question.  Cases that are complicated should be reviewed before the patient gets off the table.  We want to minimize the number of call-backs.

            Emergency MR approval should only be for real emergencies, such as acute osteomyelitis or abscess, deteriorating neurologic status, or other urgent conditions.  Otherwise, the patient should be scheduled through the routine MR scheduling system.

            Contraindications for MR imaging include cerebral aneurysm clips, pacemakers, cochlear implants, penile prostheses, metallic foreign bodies in the periorbital region.  Orthopedic instrumentation is not a contraindication.  Skin staples need to be securely covered in the fresh postoperative period.

            Cases requiring sedation need to be scheduled with the MR technicians to coordinate anesthesia.  Sedation is typically necessary for young children, patients with significant movement disorders, and severely claustrophobic patients.  Claustrophobic patients may be referred to one of the many Open Air systems in the city.  Weight limits for our MR tables are approximately 300 pounds.  If the patient is too heavy for one of our MR systems patients should be referred to an Open Air facility.

            Reading of MR cases typically is done the day following the examination.  Fellows can provide stat wet readings on their own but formal readout should be with an attending physician.  Correlative imaging studies need to be available at the time of readout of MR cases.  All cases need to be dictated and entered into the MR log book.

Instructions for MR Technicians:

          The musculoskeletal fellow  will protocol all musculoskeletal MR cases in advance.  Please check the protocol on the request sheet carefully before starting the case.  If "routine protocol" is specified, please use the attached protocols.  Any deviations from the routine protocol will be indicated on the sheet in sufficient detail for you to understand the substitution.  If you can not perform the routine protocol or if you have questions, please phone or page the musculoskeletal fellow covering your institution.  The number at the UCSD bone board is 619-543-5277 and the number of the Thornton bone board is 858-657-6780. The number at the VA for teleradiology is 858-552-7408.

The list of fellows covering the services and their pager numbers will be available through the chief technician. A current bone fellow schedule is also accessible through our website www.bonepit.com

Please page the musculoskeletal fellow  if a "wet reading" is requested.  If you can not reach the fellow, please page the attending radiologist covering bone (check the radiology faculty schedule to know who to page).

            Study quality is the responsibility of the technician.  Please put the initials of the technician in the comments area on the MR so we know who to contact if the examination needs to be repeated or if we need to speak to the technician.  Fat suppression is particularly problematic and is often non-uniform.  Please check the fat suppression and if it is not adequate, repeat the study.

            Be sure to have the patient complete the history sheet as part of their examination preparation.  The bone questionnaire needs to be completed so we have adequate clinical information.

            Liberal use of skin markers in encouraged over the specific site of symptoms or over any palpable mass.  The markers should be applied lightly, without deforming the skin. 

Shoulder Routine

Coil:                    Shoulder

Positioning:       Supine, external rotation of shoulder

R/O Rotator cuff tear

R/O Internal derangement

R/O Impingement

Shoulder pain

Technicians – Do the axial sequence first.  Please film the axial image with selected slice angles.

Shoulder MR Arthrography (Instability and Postoperative)

R/O labral tear

Evaluate instability

History of  dislocation

Rotator cuff surgery

            Patients being evaluated specifically for instability should all be examined following intraarticular injection of Gd-DTPA.  Discuss the case with the referring physician and schedule for an MRA rather than a conventional MR.  The patient should be scheduled for an arthrogram one hour prior to the MR study.  Postoperative cases are also best evaluated with intraarticular contrast.  If there is a clinical question of adhesive capsulitis, intravenous contrast enhancement can be helpful.

Elbow

Coil:                    Flex-wrap

Positioning:       Supine, elbow extended and supinated at side

            The elbow is difficult to position comfortably.  We prefer the supine position with the elbow by the side and the elbow fully supinated. Prone positioning, with the elbow placed above the head, is an alternate position that brings the elbow to the isocenter but the elbow is distorted and this position is less comfortable for the patient and they tend to move.

            Do the axial sequence first to select the correct planes for the coronal and sagittal. The coronal sequence should be along the axis of the epicondyles and the sagittal perpendicular to the epicondylar axis.  The ligaments are difficult to visualize if the coronal is not done correctly. 

Go along the plane of the anterior humeral condyles at the level of the medial epicondyle on the axial images to get the right coronal plane. Images should be oriented prior to sending to the PACS such that the humerus is superior.         

Wrist

Coil:                    Quad Wrist Coil

Positioning:       Supine, neutral wrist

            The wrist should be comfortably immobilized to the side of the patient.  Build up the height of the wrist to the isocenter. Try to avoid excessive pronation of the wrist.  Do the axial plane first to select the optimum plane for the coronal sequence.  The coronal images should be obtained from the radial styloid to the ulnar styloid.  If the coronal sequence is not well selected, it is difficult to evaluate the TFCC and the intercarpal ligaments. 

            Images should be filmed (reversed if necessary) so that the proximal part of the joint is at the bottom of the image.

 Pelvis/Hip

Coil:                    Body

Positioning:       Supine

R/O AVN

Pelvic Pain

All questions regarding GI and GU tract go to the Body MR service!

            The pelvis examination is straightforward. The coronal images need to include the whole pelvis, including the sacrum.  The axial images need to include the entire pelvis from the top of the sacrum to the bottom of the ischial tuberosities (not just the hip joints). Avoid spectral fat saturation on the large FOV images.

 Knee

Coil:                              Extremity

Positioning:       Supine, slight external rotation and flexion of knee

R/O internal derangement

R/O meniscus tear

R/O ligament tear

The axial images must include the distal 1 cm of the quadriceps tendon, the entire patella and femorotibial joint.  

Use the axial sequence to plan the angle of the oblique sagittal. The oblique sagittal is angled 10 degrees anteromedially relative to the bicondylar line.  This plane is parallel to the outer anterolateral edge of the femur.  Do not use too steep an angle!  Film the axial image with the selected slice angles.

 Hindfoot and Forefoot

It is difficult to image the hindfoot and the forefoot together and do a good study. Please look at the indication and try to do either a hindfoot exam or a forefoot exam whenever possible. If there is a question limited to the ankle region, do the hindfoot protocol.  The hindfoot includes the heel to the tarsometatarsal junction.  The forefoot includes the metatarsals and phalanges.  For the forefoot exam, the axial slices should be angled to be as close as possible to the plane of the metatarsals.

If we need to image both feet, they must be done separately.

Coil:                    Extremity (One foot only!!)

Positioning:       Supine

Comments:        Wrap saturation pad around ankle/foot

Hindfoot   

The hindfoot examination needs to include the entire ankle and extend to the tarsometatarsal joint.

Forefoot

The forefoot protocol is the same but the study is centered differently.  The study needs to extend from the tarsometatarsal joint to the tips of the toes. Fat suppression around the toes is a problem. Please wrap with a saturation pad.

UCSD Tumors/Masses

            This protocol is only a generic recommendation.  Each case is unique! 

            Mark the area of palpable abnormality with a pellet applied loosely to the skin!  Avoid compressing the lesion with the markers or the imaging coil.  Placing markers above and below the lesion/scar is even better.

Image the tumor in a nondependent position if the patient is in pain (e.g.. position patient with posterior mass prone).

            Large tumors need to be imaged with the body coil.  Use a large FOV, contrast-sensitive sequence (FMPIR or T2-w FSE with fat-sat) to localize the lesion and determine its full extent.  For marrow assessment, a large FOV sagittal and/or coronal T1-w image should be performed. Depending on the size of the lesion, the body coil or a surface coil can be utilized for the rest of the study.  Large tumors (>10-12 cm) typically require the body coil. Moderate size tumors (5-10 cm) should have the initial sequences done with the body coil and the later sequences done with a surface coil, using a smaller FOV to study the lesion in detail.  Smaller tumors of the distal extremities can be imaged using a surface coil for the entire study.  Masses located anteriorly or posteriorly are better evaluated with sagittal images, whereas masses located medially or laterally are better evaluated with coronal images. 

            Fat-suppressed post-GD-DTPA images are obtained if necessary.   

Limited R/O Occult fracture

(this is a limited charge protocol)

            The occult fracture protocol is reserved for patients unable to weight-bear, with normal or equivocal radiographs.  Almost all requests are for the pelvis or hip.  The study is done during normal working hours. 

            These screening studies should be monitored and a wet reading should be provided.  Use the larger FOV fast IR and T1-w SE to find the areas of osseous abnormality.  Study abnormal areas with a smaller FOV T1-w sequence to define the extent of the fracture line.

R/O Pelvis/Hip fracture

R/O Knee fracture

Specific question about cartilage growth plate injury (pediatric)

R/O bony bar

            Add 1 of the following, the specific plane depend on indication.  This is a lengthy sequence so it should only be added if there is a specific issue about premature growth plate fusion. 

            The coronal plane is generally the best plane for evaluating the growth plate.