How to Read a Hip Mri Arthrogram
MRI examination
by Mark Anderson
Academy of Virginia Health Sciences Center
Publicationdate
This review is dased on a presentation given by Mark Anderson and adapted for the Radiology Banana by Robin Smithuis.
We will discuss:
- Basic MR techniques and MR arthrography.
- Appearance of normal anatomic structures.
- Mutual types of pathology.
MRI technique
Scan planes
Merely like in the shoulder yous need to be certain to get the imaging planes correctly in a standardized style.
Use the centrality of the epicondyles on a axial localizer to plan the coronal browse.
The sagittal images are scaned perpendicular to the coronal scan.
In this mode yous get very persistent images and you will get used to the normal anatomy.
Imaging sequences
T1
In every joint that is studied y'all should have at to the lowest degree one T1-sequence non only to look at the beefcake, just also as a back up for looking at the marrow.
Ofcourse the T2-fatsat images volition prove marrow abnormalities, but T1 can be helpful in telling the states what is really going on.
T1 is certainly used in MR-arthrography.
T2-fatsat
T2 volition show u.s. most of the pathology, whether it is in the os marrow, ligaments or muscle because of the high h2o content. It tin also exist used to image cartilage.
Gradient echo
With gradient repeat we can use 3-D sparse sections to prototype the cartilage and the ligaments.
In the MR-protocol nosotros exercise T1 and T2-fatsat in all three imaging planes.
Sometimes STIR is used.
MR-arthrography
Typically the radiocapitellar joint is punctured from lateral with the patient prone and the arm flexed xc degrees overhead (red arrow).
This however tin can sometimes cause issues if you are interested in the lateral ligaments and you lot inject lidocaine or contrast into these ligaments.
So more recently we started to use the posterior approach into the olecranon fossa (blueish arrow).
Diluted gadolinium is injected, i.due east. 0,05cc + 10cc saline (an "off-label" use in the US).
Indications for MR-arthrography are:
- UCL pathology in throwers.
- Osteochondral lesions and repair
- Loose bodies
Beefcake and Pitfalls
When you study the anatomy of the elbow, it is good to use the inside-out arroyo.
First study the bones and then continue with the ligaments and the tendons and then the surrounding structures.
Tendon attachments
Common flexor tendon
Attaches at the medial epicondyle
Ulnar collateral ligament or UCL
Starts at the undersurface of the medial epicondyle and runs down to the sublime tubercle, which is the medial side of the coronoid process.
Common extensor tendon
Originates at the lateral epicondyle.
Lateral collateral ligament
Originates just underneath the attachment of the common extensor tendon.
Lateral ulnar collateral ligament
This is a somewhat confusing term for a tendon that also originates just underneath the common extensor tendon. It swings downwardly backside the radial head and attaches at the area of the ulna that is called the supinator crest - see lateral view.
Biceps tendon
Attaches on the radial tuberosity.
Brachialis tendon
Attaches on the coronoid process.
Annular ligament
Attaches on the volar side of the sigmoid notch of the ulna and runs around the radial caput and attaches on the dorsal side of the sigmoid notch.
Pseudodefect of the capitellum
This is a finding that yous frequently see on coronal images.
Information technology looks like an osteochondral lesion, but if you await at the sagittal image you lot volition notice that the coronal image runs through the posterior non-articular portion of the capitellum.
Then when the elbow is fully extended, a portion of the radial caput is actually behind the carticular surface of the capitellum.
On a coronal view we will exist looking at the radial caput which is covered with cartilage and opposite to it the non-cartilage covered part of the capitellum, which oftentimes is somewhat irregular.
Pseudo-loose trunk
Another common finding is a pocket-sized slice of fat that you'll come across on the sagittal epitome, that looks like a small loose body or a cartilage defect.
This can be explained if we look at the articular surface of the olecranon.
Typically the olecranon has ii pieces of cartilage with a small area inbetween, that fills with fat.
Plica
This structure on the lateral side of the articulation is sometimes seen and is a plica.
It can be prominent and almost look like a meniscus.
It is a normal structure, but sometimes it is thickened or irregular and it may be a cause of symptoms.
Elbow Mechanics
The elbow serves as a hinge joint when we look at the humeroulnar and radiocapitellar joint.
The other articulation is the proximal radioulnar joint with rotation allowing pronation and supination.
Many acute and chronic injuries occur every bit a result of throwing.
During the throwing motion in the phase of tardily cocking to dispatch, there are tremendous valgus forces that are pulling the elbow.
The valgus overload results in enormous tension on the medial side trying to pull things apart (yellowish arrows), while the lateral side will exist under compression (blueish arrows).
On the posterior side information technology causes shear forces along the head of the olecranon (black pointer).
Valgus overload syndrome
All these forces make up what is called the "valgus overload syndrome" with very characteristic injuries to the elbow over time.
- The tension on the medial side causes a tear of the ulnar collateral ligament.
- Compression on the lateral side causes an osteochondral lesion of the capitellum.
- The shear forces on the posterior side cause arthrosis.
Arthrosis in valgus overload syndrome
Due to the valgus overload in that location are shear forces on the posteromedial part of the humeroulnar joint.
Notice the subchondral sclerosis seen on the T1W-image (red arrow).
On the T2W-epitome at that place is subchondral os marrow edema and cartilage loss (yellow pointer).
These are images of a 20 year quondam baseball pitcher.
Scroll through the images.
On the coronal images at that place is a beautiful anterior package of the UCL, merely find that there is osteophyte formation on the medial part of the joint (blood-red arrow).
Equally we go farther posteriorly there is a small area of depression bespeak intensity (yellow pointer), which is an avulsion of part of the UCL.
This is better appreciated on the radiograph.
Continue with the centric scan.
As we look on the axial scan, nosotros can appreciate the huge osteophyte formation.
Find that the ulnar nervus (blue arrow) is next to these osteophytes and these patients may present with ulnar neuropathy.
Posterolateral Rotatory instability
There are different stages of instability of the elbow articulation and the final stage is dislocation.
In stage 1 there is subluxation of the ulna and there is trigger-happy of the lateral ulnar collateral ligament.
In phase ii there is more injury, where the coronoid perches the trochlea and there is more ligamentous injury.
In stage 3 finally the coronoid ends up behind the humerus in a true dislocation and you may tear the ulnar collateral ligament, which results in a very unstable - floating - elbow.
Elbow dislocation
Here a lateral view of the elbow of a patient who barbarous on the outstretched arm.
The radiograph shows articulation effusion (red arrows) and a coronoid fracture (yellow arrow).
Continue with the MR-images.
Now here is the MR.
Study the images and then continue reading...
Coronal view:
- Lateral collateral ligament is completely stripped (yellow arrow).
- radial caput is subluxed.
- marrow edema of the coronoid process due to the fracture (carmine arrow).
Sagittal view:
- Radial head is a picayune bit subluxed posteriorly (yellow pointer).
- Large effusion and capsular disruption posteriorly.
- Contusion of the posterior side of the capitellum every bit a result of impaction by the coronoid process (red arrow).
All these signs are the result of a posterior dislocation.
Read more in the article of Zehava Rosenberg in AJR 2008 entitled: MRI Features of Posterior Capitellar Impaction Injuries
These images are of a 23 yr one-time male person who brutal onto his outstretched manus 2 weeks agone while skateboarding.
On physical exam there was decreased range of motion of the elbow and tenderness along the lateral aspect.
Offset study the images, then proceed reading...
What is the construction on the axial image behind the radial head?
Sagittal view:
- Again the feature pattern of marrow edema that is seen in posterior elbow dislocation with contusion in the anterior side of the radial caput (cerise arrow) and on the posterior side of the capitellum.
- The radial head must accept striking the posterior role of the capitellum.
The structure backside the radial head is the annular ligament.
It is irregular and thickened as a result of the posterior dislocation.
Osteochondral lesions
OC lesion of capitellum
Osteochondral lesion is the new name for osteochondritis dissecans or OCD.
The chronic valgus overload can cause an osteochondral lesion on the lateral side of the elbow.
It is the upshot of repetitive impaction and shear forces.
The radiograph is of a 15 year old baseball game player with four yr history of elbow pain and a recent episode of locking.
There is a focal lucency in the capitellum and some fragmntation.
This is typical for a osteochondral lesion of the capitellum and the locking is probably the result of loose bodies.
Continue with the MR...
The MR-arthrogram confirms the osteochondral lesion.
There is gadolinium in between the humerus and the osteochondral lesion which indicates that it is unstable.
If you don't have gadolinium, look for joint fluid undercutting the fragment.
There is a loose body in the posterior recess of the radiocapittelar joint.
Find also the fragmentation equally seen on the axial paradigm.
The osteochondral lesion of the capitellum is typically seen in throwers and gymnasts (xi-15 yrs), who get a lot of wrist and elbow bug due to weight begetting.
Here some other instance in a 20 year quondam gymnast.
Once again there is lucency on the radiograph.
The MR-arthrogram shows some bone marrow edema on the coronal view.
The sagittal T1W-image shows subchondral os abnormality, but not much of a fragment.
There is some cartilage thinning, but not a defect.
This is obviously a stable fragment and there were no loose bodies.
These images are of a young baseball player, who presented with elbow pain at historic period 14.
The T2W-fatsat epitome shows marrow edema and maybe in that location is a subchondral fracture.
Manifestly someone told him to go on throwing, because he came back three years subsequently at age 17 and y'all can come across what can happen when they push too hard in getting these kids to get a professional.
The T1W-prototype shows fragmentation (yellow arrow) with a loose body (scarlet arrow).
The T2W-image demonstrates that the fragment is unstable considering there is high point between the fragment and the humerus.
At arthroscopy there is depression and irregularity of the cartilage of the capitellum.
First the loose bodies were taken out.
Then frequently an OATS-procedure is performed, which we will discuss now.
OATS procedure
OATS stands for osteochondral autologous transfer.
Pieces of cartilage and bone are taken out of some other non-weight bearing bone and tranferrred to the capitellum.
In this patient the cartilage is taken from the non-weight begetting role of the knee.
Then holes are drilled in the capitellum and the defects are filled with the autologous bone and cartilage.
Hither the hole in the capitellum is filled with four pieces of bone and cartilage.
The radial head is seen opposite the capitellum.
OC lesion of trochlea
These images are of a patient with inductive elbow pain.
At that place was no recent injury.
The clinical diagnosis was a biceps tendinitis or a bicipital bursitis.
The findings on the coronal MR-images are quite uncommon.
If you would see this in the capitellum you lot would call information technology an osteochondral lesion of the capitellum.
So this is called an osteochondral lesion of the trochlea.
Detect the minor cystic changes (white pointer).
There is also a small cartilage defect.
An osteochondral lesion of the trochlea is ordinarily seen in younger patients, who have an young skeleton.
It is seen in the lateral trochlea like in this case due to repetitive hyperextension in an area with tenuous blood supply.
Information technology is also seen in the medial trochlea due to laxity and posteromedial abutment.
Here a different patient.
Discover that it is a young patient, because the physis is still open up.
There is a large osteochondral lesion in the lateral trochlea (xanthous arrows).
Find the edema in the subchondral bone (red arrow).
The cartilage is still intact.
Ulnar Collateral Ligament
The ulnar collateral ligament (UCL) is situated on the medial side and it has iii components.
The anterior packet is the strongest component and is the master restraint against valgus forces.
On MR this is the almost of import structure.
The posterior parcel attaches distally in a fan-shape on the olecranon.
It forms the flooring of the cubital tunnel.
The transverse bundle runs from the olecranon to the olecranon, so information technology doesn't exercise much.
The UCL (in xanthous) originates on the undersurface of the medial epicondyle just beneath the origin of the common flexor tendon.
It attaches on a small-scale process on the medial side of the coronoid, which is chosen the sublime tubercle.
E'er use the axial images when yous report the ligaments, especially the UCL.
Scroll through the images.
- If you look at the medial epicondyle you will notice the posterior bundle as a thin structure (bluish arrow).
- Notice the ulnar nerve sitting in the cubital tunnel.
- The posterior bundle forms the flooring of the cubital tunnel.
- A retinaculum covers the cubital tunnel.
- Notice that the anterior bundle is much thicker (white arrow).
- You tin see the departure between the inductive and posterior ligament fifty-fifty though they form one ligament.
- Equally we go distally nosotros'll meet that they merge together to attach to the sublime tubercle.
text
Here nosotros run into two consecutive coronal images of the UCL.
Information technology is normal to see some high indicate in the proximal part (arrow).
Notice how information technology firmly attaches to the sublime tubercle and compare this to the adjacent images.
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UCL tear
Recollect that the UCL should attach very tightly on the sublime tubercle.
In this case information technology doesn't, then even on these two images yous tin tell that there is a consummate tear.
Discover that there is some marrow edema in the sublime tubercle.
The mechanism of injury to the UCL is usually chronic tensile forces, which create microtears.
This is seen in pitchers and other overhead throwing-athletes.
A tear tin besides occur in a fall on the outstretched paw.
Most normally there is a consummate tear, but sometimes there is a partial tear which can exist very hard to come across.
That is why in these athletes MR-arthrogram is usually performed.
Study the images and and then continue reading...
This is a 18 year old baseball pitcher with medial elbow pain.
A fractional tear is seen creating a 'T-sign'.
Start written report the coronal T2-fatsat images and then go along reading...
Notice that the anterior packet is intact and firmly attaches to the sublime tubercle (yellow arrow).
On the next 2 images there is some soft tissue edema and more aberrant signal posteriorly (ruby arrow). So nosotros doubtable pathology of the posterior bundle.
Now you remember that the axial images tin be helpful.
So proceed with the centric image.
On the axial image nosotros nicely see the anterior packet is o.k. (scarlet arrow).
At that place is but some edema next to it.
However the posterior bundle is not o.grand.
This is partial fierce.
Nosotros run into this occasionally in throwing athletes, where the inductive bundle is intact and their elbow is not unstable.
They somehow accept torn their posterior parcel, which causes pain.
They do non need surgery, only it withal may go on them out of the game for quite a while.
Now here is the terminal case.
This is a 38 year former male person who has been weight-lifting for xx years.
He complains of intermittent elbow pain and popping.
Notice that the UCL is abnormal with some areas of very high signal indicating a partial tear.
On the lateral side at that place is subchondral edema and cartilage.
This is arthrosis secondary to chronic instability due to the chronic partial tearing.
UCL repair
UCL repair is washed by placing tunnels in the medial epicondyle.
They run done to the sublime tubercle and a graft is placed in between them.
This radiograph is of a 26 year old professional baseball actor who had a UCL reconstruction.
Observe the tunnels (arrow).
This operation usually works very well.
If you scroll through the MR-images you tin can see the tunnel in the medial epicondyle.
Just similar in an ACL-graft we can run into the low signal of the graft going all the way down.
On the coronal images despite the spiky artifacts it nigh looks like a normal UCL.
Here nosotros run into images of a patient afterwards repair who did not do so well.
At that place is fragmentation of the bone and disruption of the graft.
On the CT-scan information technology is better appreciated that at that place is a fracture through the tunnel.
Lateral Collateral Ligament
Here an illustration of the lateral collateral ligament complex.
It consists of the radial collateral, the lateral ulnar collateral and the annular ligament.
When you look for the radial collateral ligament, first try to place the mutual extensor tendon, considering right underneath it you will find the radial collateral ligament (yellow arrow).
As yous become more posteriorly you will meet the LUCL - the lateral ulnar collateral ligament, which sweeps behind the radial head (white arrows).
The annular ligament is unremarkably difficult to differentiate from the RCL, but sometimes it can be identified on a sagittal MR-artrogram.
Curl through these images.
You can likewise enlarge them.
Common Extensor Tendon
The common extensor tendon originates at the lateral epicondyle.
On a T1W-images the tendon should have a depression bespeak intensity (yellowish pointer).
Lateral Epicondylitis
Lateral epicondylitis is as well known as the tennis elbow, although in 95% of cases it is seen in not-lawn tennis players.
It is due of chronic stress to the common extensor tendon, which results in partial tearing and tendinosis.
Typically, the extensor carpi radialis brevis is the component that is involved.
In more severe cases there is tearing of the LCL, which gives a poor response to conservative handling.
Here a typical case.
There is thickening and abnormal intrinsic betoken on both T1- and T2W-images.
Common Flexor Tendon
The mutual flexor tendon originates at the medial epicondyle.
On a T1W-images the tendon should have a low signal intensity (blood-red arrow).
Medial Epicondylitis
This is the counterpart of the lateral epicondylitis and likewise known as the golfer'south elbow.
Hither the common flexor tendon is involved.
On the sagittal image it is clear that it is simply partial trigger-happy.
Nonetheless this tin be quite painful.
Here we take the coronal T1W- and T2W-images.
In that location is partial tearing, but information technology is very extensive.
Little Leaguer's Elbow
First written report the images of a patient with hurting on the medial side, so go along reading...
The findings are very subtle.
The medial epicondyle of the afflicted arm is somewhat more osteopenic.
In these cases we usually ask for a comparison view, considering it can exist very subtle.
The diagnosis is a Little leaguer's elbow which results from chronic stress injury.
The lucency on the radiograph, which looks like a widened physis, is due to cartilage ingrowth in the metaphysis.
Go on with the MR...
On the MR the abnormality is very obvious.
In that location is marrow edema in the medial epicondyle and also in the adjacent bone (yellow arrow).
Little Leaguer'southward elbow is also known as medial apophysitis and some call it epiphysiolysis.
By the way this could too be chosen a Salter-Harris blazon I fracture, if information technology was an acute traumatic event.
Detect the normal ulnar collateral ligament (red pointer).
In children the weak link in valgus stress is not the ulnar collateral ligament but the physis.
Here another example.
This patient is a footling bit older.
The left epicondyle is already fused, but on the correct the physis is still a little bit open.
Keep with the MR...
On the MR there is marrow edema.
Observe that there is also some edema where the ulnar collateral ligament attaches, so there is also some tearing of the UCL.
Hither some more views of a different patient.
Biceps tendon
Scroll through the centric images of the biceps tendon from the musculotendinous junction to the zipper on the radial tuberositas.
The pathology of the distal biceps tendon is much similar pathology in the achilles tendon.
At that place can exist tendinosis, partial tear and complete tear with or without retraction.
Here are the ultrasound images of a 73 year one-time male who experienced a sudden pain and a vehement sensation when lifting a box.
There was pain with pronation and supination and tenderness anteriorly proximal to the elbow joint.
No ecchymosis or palpable mass.
On the sagittal image the tendon is thickened, just distally the tendon is lost.
MRI examination was performed.
Now look at the MR-images and try to figure out if the tendon is retracted and whether there is a partial or consummate tear...
Well on the sagittal prototype it looks equally if the tendon is completely thorn, but continue with the next images.
Tear of distal biceps tendon
In that location is a consummate tear, because if we follow the tendon all the way to the radial tuberosity, we can meet that the tendon does not adhere there (dark-green arrow).
There is but fluid.
The reason why the tendon is not retracted is because the broad bicipital aponeurosis - besides known as lacertus fibrosus - is nonetheless intact (scarlet arrow).
The distal biceps tendon non only inserts to the radial tuberosity, just too via the lacertus fibrosus into the fascia of the flexor pronator mass on the medial side of the forearm.
The distal tendon of the biceps is encircled on the upper left paradigm.
When the aponeurosis is also thorn, and so the tendon retracts and you lot become an obvious swelling in the arm caused by the contracted biceps muscle.
A distal biceps tendon tear is an uncommon injury.
It is seen in about 5% of biceps injuries.
It is the outcome of a sudden extension force to the arm when the elbow is flexed.
A proximal biceps tendon tear is more common.
Commonly it is the long head of the biceps that is completely torn.
Here some other instance.
On the T1W-prototype there is some thickening and some intermediate point.
This could be tendinosis, but e'er look at the T2W-images to look for a tear.
In this case there is a partial tear.
Hither another case.
On the sagittal images we were not sure virtually a possible tear.
Maybe there just was some tendinosis or tendinitis.
The centric images demonstrate a high class fractional tear (ruby arrow).
Always brand sure that your axial scan goes all the way to the tuberosity, because is y'all stop too early on, like in this case, so you will only come across a thickened tendon and some fluid, but you are not certain nearly a possible tear.
Here an easy case, because the tendon is retracted as can exist best seen on the sagittal epitome.
So the lacertus must also have been torn.
Radiobicipital bursitis
Here are sagittal and axial images of a patient who was referred to an orthopedic oncology surgeon for a mass near the elbow.
In that location is a fractional tear (arrow) of the biceps tendon, but the question is, what is the construction that we are looking at and what is inside it.
The structure is the radiobicipital bursa, so this is a bursitis.
Remember that the biceps tendon does non have a tendon sheaht, then tenosynovitis is not a possibility.
The differential diagnosis for the low intensity structures inside the bursa is: synovial chondromatosis, PVNS and rice bodies.
It turned out to be rice bodies.
In any synovial lined joint or bursa these rice bodies can be formed as a result of chronic inflammation with synovial hypertrophy.
The villi will outgrow their blood supply, become necrotic and fall into the joint or bursa.
They are called rice bodies considering when you open the joint, they only look like rice.
Here another instance.
The white arrow in the left sided image is pointing to the bursa.
Notice that the biceps is intact.
Next to the radiobicipital bursa (xanthous arrow), also an interosseous bursa (red arrow) was described by Abdalla Skaf in Radiology in the article entitled: Bicipitoradial Bursitis: MR Imaging Findings.
Sometimes these masses mimic a tumor or they can cause impingement on the radial nervus when they become very large.
Brachialis tendon
The brachialis originates from the lower half of the front of the humerus, nearly the insertion of the deltoid musculus.
It lies deeper than the biceps brachii, and is a synergist that assists the biceps in flexing the elbow.
The thick tendon inserts on the anterior surface of the coronoid process of the ulna.
On a sagittal view, when you compare the brachialis tendon (xanthous arrows) with the biceps tendon (ruby-red arrows), notice that the brachialis is most all muscle.
Information technology only has a very short tendon distally.
Chronic avulsion
This paradigm is of a 68 twelvemonth old woman who injured her arm approximately 10 years previously and at present presents with increasing hurting in that arm.
First study the radiograph and then keep with the MR...
First written report these axial T1W-images and then continue reading...
Radiograph
The cortex of the ulna is irregular and in a 68 year one-time woman in that location was business organisation of underlying bone abnormality similar for instance a os tumor.
MRI
The biceps tendon is indicated past the red pointer and demonstrates tendinosis and partial tearing.
However when we look at the insertion of the brachialis tendon on the coronoid procedure, there is tearing of the tendon with a lot of bone marrow edema equally seen on the fat suppressed T2W-image.
In fact this was a chronic blazon of avulsion injury with partial vehement of the tendon.
The bone reaction can mimic an ambitious bone lesion.
Hither another chronic avulson, which was sent to the oncologic surgeon, because there was business organization about a possible juxta-cortical osteosarcoma.
The MR even so revealed the following:
- The lesion was located at the insertion of a latissimus dorsi tendon to the humerus (yellow pointer).
- The bone marrow has a niggling fleck of high signal, but otherwise does not wait that aberrant.
- There is as well injury to the muscle aswell (red arrow).
Chronic avulsive injuries are common in adolescents, but may besides be seen in older patients.
The problem is that they may mimic infection or tumor.
Fretfulness
Scroll through the images.
Ulnar nerve
Hither we run across the ulnar nerve within the cubital tunnel.
The posterior band of the ulnar collateral band forms the floor of the tunnel, while the retinaculum forms the roof.
First study the images.
This patient had ulnar nerve neuropathy.
What is the cause?
Cubital tunnel syndrome is a common peripheral neuropathy.
Information technology arises from compression of the ulnar nerve within the cubital tunnel, where the nerve passes below the cubital tunnel retinaculum.
Possible causes of cubital tunnel syndrome:
- Overuse
- Subluxation of the ulnar nerve because of built laxity in the fibrous tissue
- Humeral fracture with loose bodies or callus formation
- Arthritic spur arising from the epicondyle or olecranon,
- Musculus anomaly (eg, an accessory anconeus muscle) as is nowadays in this instance.
- Soft-tissue mass: ganglion, lipoma, osteochondroma, synovitis secondary to rheumatoid arthritis, infection (eg, tuberculosis), and hemorrhage.
Read more on neuropathy in the 2006 Radiographics article by Gustav Andreisek et al entitled:
Peripheral neuropathies of the median, radial and ulnar fretfulness: MR imaging features.
What is missing in this epitome and what is the probable cause...
The ulnar nervus is non where it is supposed to be.
Now the nerve could be dislocated, simply in this case the nerve was surgically transposed.
Ulnar nervus transposition is performed in patients in whom the ulnar nerve is compressed against the medial epicondyle.
And then the question is, when they have the ulnar nerve out of the tunnel, where do they put information technology.
This can exist subcutaneous, submuscular or intramuscular.
And so when we go back to the image, you will discover that it can be difficult to find the nerve.
Whatsoever of these subcutaneous structures could be the transposed nervus.
A fashion to do information technology, is to follow the structures distally until you lot find the ulnar nerve distally in its normal position in the proximal forearm surrounded by fat.
Then when you follow it proximally, you will notice that this was a subcutaneous transposition.
In this case, there is neuritis.
There is enlargement of the nerve.
On the T2W-image at that place is high signal.
Another sign is not-uniform enlargement of the fascicles, which is seen on the sagittal paradigm (arrow).
Radial nerve
The radial nerve tin exist all-time identified at the level of the radial head, where y'all can see superficial and deep branches in the radial tunnel (arrows).
This is a very consistent place to find the radial nervus.
The deep radial branches class the posterior interosseus nerve which penetrates the supinator muscle at the arcade of Frohse (arrow).
Study these images and then continue reading.
What are the findings?
The findings are:
- On the upper left T1W-image there is high signal fat within the extensor muscles with loss of muscle majority which indicates fatty cloudburst.
- The centric epitome on the upper right shows a mass more proximally in the supinator muscle.
- The sagittal images confirm that this is a lipoma.
So the atrophy is a upshot of compression of the posterior interosseous nerve, which is a co-operative of the radial nerve.
Median nerve
The median nerve goes down behind the Lacertus fibrosis, which is the aponeurosis of the biceps and penetrates the pronator muscle.
Denervation
Nerve pathology can present as thickening of the nerve when there is neuritis or as a result of compression of the nerve.
A secondary sign of nerve pathology is denervationwith edema and/or atrophy of the muscle.
In this instance there is chronic atrophy with loftier sinal on T1, which is irreversible.
In early on or subacute denervation the prominent sign is edema with loftier signal on T2W-images and that is reversible.
This is a 48 yr one-time male with Marfan's syndrome, who had a sudden onset of right hand weakness.
This is a nice example of subacute denervation.
Notice on the T1W-epitome that there is no cloudburst.
Simply edema on the T2W-paradigm.
This was due to proximal radial neuropathy.
Soft Tissue Masses
Around the elbow all kind of soft tissue masses can occur, which are also seen in other places.
If y'all cannot brand a specific diagnosis, merely call the mass indeterminate an practise a biopsy, because in many cases y'all cannot tell the diagnosis.
The epitome shows an oval lesion, which but looks like a schwannoma, because it is elongated and it looks equally if information technology follows the nerve, but information technology turned out to exist a synovial sarcoma in an eleven twelvemonth former male child.
Merely make a diagnosis when yous are sure of a specific diagnosis like bursitis, AVM, lipoma, PVNS or a cyst or hematoma.
True cat scratch affliction
Here a 37 year quondam male who presented to the emergency department with pain, swelling and a mass at the left elbow that had been increasing over the final 3 weeks.
On MR a mass was seen just to a higher place the medial epicondyle, where the epitrochlear lymph nodes live.
The mass is very heterogeneous as is the enhancement.
Based on the MR-findings you notwithstanding have to phone call this mass indeterminate.
The final diagnosis was cat scratch affliction based on high Bartonella henselae titers.
Here images of a 26 year old female who also came with a mass in the peritrochlear region.
It looks quite homogeneous and cystic.
Continue with the mail service-Gd image.
Observe the inhomogeneous enhancement on the MRI and prominent internal vascularity on the sagittal ultrasound image.
So this was not a cystic mass.
Again this was diagnosed as indeterminate.
The final diagnosis at biopsy was Lymphoma.
Hither some additional images of the nerve-sheath tumor look-a-like, which turned out to be a synovial sarcoma.
Source: https://radiologyassistant.nl/musculoskeletal/elbow/mri-examination
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