MRI - Imaging modality of first choice for depicting the anatomy and pathology of the brachial plexus.
MRI - very well demonstrate the anatomy due to its inherent contrast differences between the nerves with low signal intensity and the surrounding hyperintense fat on T1-weighted images.
Challenges:
Large field of view
Other heterogeneous tissue distribution including fat, muscles, and bones.
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Brachial plexus MRI
1. Imaging in Brachial Plexus
Presenter: Dr. Parameshwar Keerthi B H.
Moderators: Dr. Anil Kumar Sakalecha
2. Contents
• Introduction
• Anatomy of Brachial Plexus
• Imaging protocol
• How to identify Brachial plexus in imaging
• Brachial plexus pathology – Classification
• Imaging in Brachial plexus pathologies
• Conclusion
3. Introduction
• Brachial plexus - sensory and motor innervation of the
upper extremity.
• Involved in a variety of traumatic and non-traumatic
pathologies.
• MRI - diagnosis and in localization of these lesions.
• Significant impact on the management.
4. Introduction
• MRI - Imaging modality of first choice for depicting the
anatomy and pathology of the brachial plexus.
• MRI - very well demonstrate the anatomy due to its
inherent contrast differences between the nerves with
low signal intensity and the surrounding hyperintense fat
on T1-weighted images.
• Challenges:
– Large field of view
– Other heterogeneous tissue distribution including fat,
muscles, and bones.
6. Anatomy of Brachial Plexus
• The brachial plexus originates from the cervical spinal
nerves C5–C8 and the first thoracic spinal nerve T1.
• The spinal nerves split into anterior (ventral) and
posterior (dorsal) rami just distally of the dorsal root
ganglion.
• The dorsal rami innervate the paraspinal muscles.
• The five ventral rami C5, C6, C7, C8 and T1 form the
brachial plexus.
7. Anatomy of Brachial Plexus
• C5 and C6 join to form the upper trunk, C7 continues as
the middle trunk, and the inferior trunk is formed by C8
and T1.
• All three trunks divide into an anterior and posterior
division.
• The six divisions intermingle and form the three cords:
the lateral, posterior and medial cord.
• The anterior divisions of the upper and middle trunks
form the lateral cord, the anterior division of the lower
trunk continues as the medial cord, and the posterior
divisions of all trunks unite to form the posterior cord.
8. Anatomy of Brachial Plexus
• The individual cords - named according to their
relationship to the adjacent subclavian artery: lateral,
posterior, and medial.
• Inferior to the clavicle – cord divide into individual
branches providing motor and sensory innervation to the
upper extremity
• Lateral border of the pectoralis minor muscle - the cords
divide into the five peripheral nerves which innervate the
shoulder and arm: the median, ulnar, radial, axillary and
musculocutaneous nerves.
10. MR Brachial Plexus - Protocol
• Coronal 3D STIR (include both shoulders) FOV - 350mm.
• Coronal MIP FOV- 350mm.
• Coronal T1 (include both shoulders) FOV - 320mm.
• Axial STIR (C5 to inferior axilla, single-side) FOV -
200mm.
• Axial T1 (single-side) FOV - 200mm.
• Sagittal T2 (C-spine to midpoint of arm) FOV - 240mm.
11. MR Brachial Plexus – Specific Sequences
• Intravenous Gadolinium:
– Administered in patients with tumors or mass lesions.
– Not administered in patients with traumatic brachial
plexopathy.
• Traumatic brachial plexus injury –
– sagittal T2-weighted images are obtained through the
cervical spine followed by axial T2-weighted images
from C4 to T2 levels.
– 3D gradient echo (GRE) sequence with thin slices - to
look for the nerve root avulsion.
12. MR Brachial Plexus – Specific Sequences
• Thoracic outlet syndrome - sagittal T1-weighted images
are obtained through the symptomatic side extending
from midline to the axilla with arm in hyperabducted
position.
• These are compared with similar sagittal T1-weighted
images obtained with arm in neutral position by the side
of body.
15. Identification of Roots
• The brachial plexus is predominantly formed by the
ventral rami of the spinal nerves of C5 through T1.
• They exit the neural exit foramina and form the roots.
• On the sagittal images the proximal part of the first rib is
used to identify the C8 and T1 nerve roots, with C8
above and T1 below the first rib.
18. Interscalene Triangle
• The nerve roots and the subclavian artery enter the
interscalene triangle.
• It is formed by the anterior scalene and middle scalene
muscles.
• Just lateral of the interscalene triangle the three trunks
are formed
21. • The divisions are located at the level where the brachial
plexus crosses the clavicle.
• The cords are positioned above and around the axillary
artery and they are named after their position relative to
the axillary artery.
• On sagittal MRI images the lateral cord is located most
anterior, the posterior cord most superior and the medial
cord most posterior.
Identification of Divisions
24. Brachial Plexus – Coronal Images
• On the coronal images the T1 nerve root can always be
easily identified as a horizontal linear structure
surrounded by fat close to the lung apex.
• At this level the stellate ganglion can also be identified.
• The C8 nerve root is also usually surrounded by fat and
easily seen.
• On the T2-STIR images the nerves have a slightly
increased signal intensity compared to the surrounding
tissues.
27. Brachial Plexus – Coronal Images
• The roots C5–C7 are surrounded by less fat and have
contact with the scalene muscles.
• To identify the trunks on the coronal images the dorsal
scapular artery can be used as a landmark.
• It is a branch of the subclavian artery supplying the
rhomboid muscles.
• This small artery runs between the superior and middle,
or middle and inferior trunk
30. Classification of Brachial Plexus
Pathologies
Brachial Plexus -
Pathologies
Non - Traumatic
Traumatic
a. Infective
b. Inflammatory
c. Neoplasm
d. Radiation
e. Vascular
f. Extrinsic compression
31. Traumatic Brachial Plexopathy
• There are two distinctive populations affected by
traumatic brachial plexopathy.
• Neonates sustain a traction injury due to shoulder
dystocia during vaginal delivery.
• The second population is young men in the second and
third decades –
– fall from a height
– motorcycle or motor vehicle crash
– penetrating injury from a gunshot
32. Traumatic Brachial Plexopathy -
Classification
• It is important to differentiate between preganglionic
and postganglionic injuries.
• Post ganglionic injuries are associated with good
prognosis.
• Post ganglionic injuries - surgery: nerve grafting
• MRI of preganglionic injuries can show nerve root
avulsions, with or without pseudomeningoceles.
33. Pseudomeningocele - Imaging
• Cerebrospinal fluid collections due to a dural tear.
• The presence of a pseudomeningocele is highly
indicative for a preganglionic lesion, seen in 80% of
avulsions.
• It is not pathognomonic.
• Spinal cord abnormalities like edema, haemorrhage and
myelomalacia are seen in ~ 20% of patients with
preganglionic injuries.
34. Preganglionic Injury
• Enhancement of intradural nerve roots and root stumps
suggests functional impairment of nerve roots despite
morphologic continuity.
• Features of denervation/atrophy in the paraspinal
muscles is an accurate indirect sign of root avulsion
injury
35. Postganglionic Injury
• MRI of show thickened nerves with hypointensity on T1-
and hyperintensity on T2-weighted images.
• Nerve contiguity can be assessed; there may be
discontinuity with distal nerve contraction.
• Increased T2 signal and enhancement of intact nerves
suggests damage or impairment despite contiguity.
• Haematoma, fracture fragment or callus formation may
also cause brachial plexopathy.
37. Traumatic Plexopathy - Complication
• Brachial plexus injuries may be associated with injuries
to the subclavian artery due to their anatomical
proximity to each other.
• Also post-traumatic pseudoaneurysm of subclavian
artery may present with delayed brachial plexus paralysis
due to compression of the brachial plexus.
39. Neonatal Brachial Plexopathy
• Occurs in approximately 1 in 1000 neonates.
• Downward traction on the shoulder girdle produces
stereotyped patterns of plexus injury.
• Nerve lesions occur first at higher levels, with more severe
traction progressive inferior extension of lesion occur.
• Superior nerve injury is typically extraforaminal,
• at the level of the superior trunks, because a welldeveloped
• investing fascia protects the upper nerve roots from
• proximal traction.
40. Classification of Neonatal Brachial
Plexus Injury
Superior Nerve Injury Inferior Nerve Injury
Extraforaminal Intraforaminal
Well-developed investing
fascia protects the upper
nerve roots from proximal
traction.
Partial or complete avulsion
of the nerve root
41. Obstetrics Brachial Palsy – Naraka’s
Classification
Types Nerve Root
involved
Deformity
Type I (Erb-
Duchenne
type)
C5 and C6 deficits Loss of shoulder abduction,
shoulder external rotation,
elbow flexion, and forearm
supination.
Type II (Extended
Erb’s)
C5 to
C7/C8 deficits
Type I with loss of wrist
extension
Type IIII C5 to C8/T1 deficits Total palsy with no Horner
syndrome
Type IV C5 to T1 and the
sympathetic chain
Total palsy with Horner
syndrome
42. Neoplasm
• Four types of neurogenic tumors of the brachial plexus.
– Schwannoma
– Neurofibroma
– Plexiform neurofibroma
– Malignant Peripheral Nerve Sheath Tumor (MPNST)
• Plexiform neurofibroma and one third of the
neurofibromas are associated with neurofibromatosis
type I
• Schwannomas - capsuled and are eccentric nerve sheath
tumors which displace the nerve fascicles and can be
resected without damaging the nerve
43. Neurogenic Tumors
• Neurofibromas do not have a capsule and invade the
nerve fascicles.
• Neurogenic tumors characteristically have an ovoid form,
and the nerve can often be seen entering and leaving
the tumor.
• In schwannomas the nerve enters or leaves the related
tumor eccentrically, while in neurofibromas the nerve
passes through the center of the tumor.
44. Imaging Findings in Neurogenic Tumors
• Neurogenic tumors will have signal intensities similar to
muscles and T2 heterogeneously hyperintesne.
• They enhance with intravenous gadolinium.
• Cystic parts may be present in schwannomas.
• Neurogenic tumors may present as an apical lung tumor.
• MPNST’s – poorly defined margins, cystic degeneration,
peripheral enhancement, perilesional edema and bone
destruction
47. Other Neurogenic Tumors
• Neurogenic tumors of nerves in the vicinity of the
brachial plexus include those of the vagal nerve, phrenic
nerve and sympathetic trunk.
• The course of those tumors is in a more vertical
direction.
• Sympathetic chain can also have a ganglion cell origin:
neuroblastoma, ganglioneuroblastoma and
ganglioneuroma
50. Superior Sulcus Tumor
• Also known as Pancoast tumor.
• Non-small cell lung carcinomas that arise from the lung
apex and invade the thoracic inlet.
• Tumor infiltration of the stellate ganglion causes Horner’s
syndrome, which is characterized by miosis, ptosis and
anhidrosis.
• Pancoast’s syndrome -
– Pain in the shoulder and arm
– Weakness and atrophy of the muscles of the hand
– Horner’s syndrome.
52. Pancoast Tumor – Imaging
• MRI useful to assess the extension of tumors towards the
brachial plexus, vertebral bodies, intervertebral foramina
and the subclavian vessels.
• Infection may radiographically mimic a malignant superior
sulcus tumor.
• Especially Nocardia is known to invade the thoracic wall.
• Contra-indications for surgery:
– Brachial plexus involvement above C8.
– Vertebral body invasion of more than 50%
– Extensive mediastinal involvement with invasion of oesophagus or
trachea.
53. Interscalene Fat Pad - Importance
• The earliest sign of extrathoracic and brachial plexus
involvement is invasion of the interscalene fat pad by the
tumor
• This fat pad lies between the anterior and the middle
posterior scalene muscles and cephalad to the lung
apex.
• The trunks of the brachial plexus are found in this fat
pad.
• In advanced disease there is direct extension and
invasion of the brachial plexus, intercostal nerves,
stellate ganglion, neighbouring ribs, and vertebrae.
54. Interscalene Triangle - Invasion
• Pancoast tumours will be involving the interscalene
triangle (middle compartment).
• Connective-tissue sheath, covering the brachial plexus
will initially displace the nerve roots or trunks superiorly
without actually invading them.
• Sensory dysfunction may occur because of extrinsic
nerve compression
• Loss of motor function is more likely to be indicative of
frank invasion of the nerve
57. Other Tumors of Brachial Plexus
• Can be benign or malignant soft tissue tumors, bone
tumors or metastatic disease.
• The most common benign soft tissue tumors is lipoma
followed by aggressive fibromatosis.
• Malignant soft tissue tumors include various types of
sarcomas, such as
– Liposarcoma
– Leiomyosarcoma
– Malignant fibrous histiocytoma
– Synovial cell sarcoma.
58. Other Tumors of Brachial Plexus
• All kind of bone tumors of the first rib, clavicle, scapula
and vertebral bodies may involve the brachial plexus.
• In this group bone metastases are the most common
cause.
• Other rare causes include plasmocytoma,
chondrosarcoma and osteochondroma.
64. Case Scenario
• A 56-year-old woman with a history of a left-sided breast
carcinoma was treated with surgery and irradiation.
• The patient was doing well until about 7 months after
termination of radiation therapy
• Then she developed weakness and pain in the left upper
extremity.
• An MRI examination was performed
67. Radiation vs Metastatic Brachial Plexopathy
• Important to differentiate brachial plexopathy due to
metastasis and radiation.
• Most common with the radiation dose of 6,000 cGy or
more.
• How to differentiate???
68. Radiation vs Metastatic Brachial Plexopathy
Imaging Features Radiation Brachial
Plexopathy
Metastatic Brachial
Plexopathy
Location Upper brachial plexus –
C5& C6.
Lower brachial plexus –
Horner’s syndrome (C7,C8 &
T1).
Pain Absent Present
Latency Period < 1 year > 1 year
Lesion Diffuse
In Radiation fibrosis –
T1/T2 hypointense.
No enhancement on T1
post contrast.
Multiple nodules or masses.
Metastatic lesion – T1
hypointense, T2 –
heterogeneously hyperintense.
Heterogeneous enhancement
on post contrast.
70. Metastatic Tumours
• Breast carcinoma - most common source of metastatic
disease causing brachial plexopathy.
• Other metastatic sources include lung carcinoma and
head and neck cancers.
• Metastatic lymphadenopathy - surround the
neurovascular bundle, resulting in vascular or neural
compromise.
• Metastatic disease from all causes - T1 hypointense and
T2 heterogeneously hyperintense lesion.
72. Thoracic outlet syndrome
• Dynamically induced compression of neural and/or
arterial structures crossing the cervicothoracobrachial
junction.
• The three spaces that are evaluated on sagittal
T1-weighted images are,
– Interscalene triangle
– Costoclavicular region
– Retropectoralis minor spaces
• MRI - important role in,
– Demonstrating neurovascular compression.
– Localizing the cause of compression.
– Identifying the structure causing the compression.
76. Causes of Thoracic Outlet Syndrome
• The costoclavicular space is the most common site of
compression followed by interscalene triangle.
• The lesions causing compression may be,
– Bony abnormalities (cervical rib, long transverse process of C7
vertebra, callus or osteochondroma of clavicle or first rib)
– Soft tissue pathologies (fibrous band, hypertrophy of scalenus
anterior muscle, scalenus minimus muscle, and fibrous scarring).
• Contrast-enhanced MR angiography may be performed with
the arm in elevated position to demonstrate narrowing of
subclavian artery.
78. Brachial Plexus Neuritis
• Acute brachial plexitis presents with shoulder and upper
arm pain lasting for few days to weeks followed by
upper arm weakness.
• Idiopathic brachial neuritis is of unknown cause but an
immune-mediated inflammatory reaction.
• Probable etiologies - viral infection, vaccination, surgery,
pregnancy, etc.
• Brachial plexitis is seen on MRI as focal or diffuse
hyperintense signal in brachial plexus.
79. Brachial Plexus Neuritis – Clinical
Features
• Affects the lower brachial plexus.
• Presents with acute onset of unilateral shoulder pain
followed by flaccid paralysis of the shoulder and para-
scapular muscles.
• Often a self-limiting course.
80. Immune Mediated Brachial Neuritis
• Includes,
– MMN – Multifocal Motor Neuropathy
– CIDP - Chronic Inflammatory Demyelinating
Polyradiculoneuropathy
– MIDN - Multifocal Inflammatory Demyelinating Neuropathy
• MMN is characterized by slowly progressive,
asymmetrical weakness of the limbs without sensory
loss.
• CIDP causes a symmetrical weakness of the limbs with
sensory loss.
81. Imaging
• MRI of the affected peripheral nerves can be abnormal.
• The nerves are enlarged and have an increased signal
intensity on T2-weighted images.
• T2-weighted images with fat suppression are very useful
in these patients.
• The lesions may, but often do not enhance after the
administration of intravenous gadolinium.
83. Multifocal motor neuropathy
• Rare autoimmune peripheral neuropathy.
• Predominantly affects the upper limbs with a distal
asymmetrical pattern.
• Lower motor neuron signs are always seen, with
fasciculations sometimes present.
• It is mediated by anti-GM1 ganglioside IgM antibody.
84. MMN – Imaging
• Asymmetrical focal or diffuse signal hyperintensity and
enlargement of the brachial plexus is classical.
• The increased signal intensity is believed to be due to
demyelination, while inflammation and oedema might
lead to swelling in nerves.
• MRI is considered to be of help to differentiate MMN
from lower motor neuron disease, with brachial plexus
MRI being normal in the latter.
85. CIDP - Chronic Inflammatory
Demyelinating Polyradiculoneuropathy
• Acquired demyelinating disease involving peripheral
nerves.
• Generally considered the chronic counterpart to Guillain-
Barre syndrome (GBS).
• Clinical Features - gradual and protracted (> 2 month)
weakness of both proximal and distal musculature
associated with areflexia and sensory changes.
86. CIDP - Pathology
• Affected nerves demonstrate segmental infiltration with
inflammatory cells (lymphocytes) and demyelination.
• Over time there is proliferation of Schwann cells and
deposition of collagen resulting in thickening of the
nerve and the characteristic onion bulb appearance.
• Denervation atrophy of the supplied muscles.
88. Sonography of Brachial Plexus
Uses-
• Entrapment neuropathies due to - Cervical rib, elongated
C7 transverse process.
• Nerve tumors from brachial plexus.
• Guiding interventions (i.e., biopsy & brachial plexus
anesthesia).
• Can detect root avulsion, nerve injury in form of a
neuroma, and scar tissue formation.
90. Imaging Pearls
• 3 important spaces to be identified?
• 5 Roots – 3 trunks – Division – 3 Cord – Branches.
• Sequences – Coronal – T1 / STIR, Axial – T1 / STIR &
Sagittal – T1 / STIR.
• Brachial Plexopathies – Traumatic & Non traumatic.
• Imaging – Prime role in differentiating metastatic
brachial plexopathy from radiation plexopathy.
91. Conclusion
• Brachial plexus has a complex anatomy and long course.
• Various traumatic and non-traumatic pathologies
affecting it can be evaluated optimally by MRI.
• Knowledge of the anatomy and proper planning of the
scan are essential for complete evaluation of the brachial
plexus.
Editor's Notes
dorsal root ganglion – identified at the level of Neural foramina.
Anterior ramus – motor and posterior ramus – sensory.
Roots – dorsal scapular, long thoracic nerve and phrenic nerve.
Trunk – nerve to subclavius and suprascapular nerve.
Medial cord – medial root of medial nerve, medial cutaneous nerve of arm, fore arm, medial pectoral nerve, ulnar nerve
Lateral root – lateral root of medial nerve, lateral pectoral nerve, musculocutaneous nerve
Posterior cord – upper / lower subscapular, thoraco dorsal nerve, axillary nerve and radial nerve.
The scan protocol followed at our department consists of coronal STIR and T1‑weighted images with large field of view (FOV), including both
brachial plexi for comparison followed by sagittal T1‑and T2‑weighted images with small FOV for high spatial resolution.
Traumatic brachial plexus injury – in addition to the previously described protocol,
Thoracic outlet syndrome - in addition to coronal STIR and coronal T1‑weighted images, sagittal T1‑weighted images are obtained through the symptomatic side extending from midline to the axilla with arm in hyperabducted position.
Sagittal T2-weighted image demonstrates the C5 to T1 roots exiting the neural exit foramina from cranial to caudal (red arrows).
(a) roots C5-T1 just lateral to the intervertebral foramina, T1 is located below and C8 above the first rib (R1).
(b) Subclavian artery (SA) and the roots C7, C8 and T1 are seen within the interscalene triangle between the anterior scalene muscle (ASM) and middle scalene muscle (MSM). The subclavian vein (SV) is positioned between the anterior scalene muscle and the clavicle.
Another important point – talk about anterior, middle and posterior compartment.
Just lateral to the interscalene triangle the three trunks are formed, the superior (ST), the middle (MT) and inferior trunk (IT).
Normal coronal anatomy. (a) Most posterior image with the horizontal course of the T1 nerve root (long arrow), very close to the lung apex. Short arrow points to the stellate ganglion.
(c) T2-STIR image at the same level as (b) shows the slightly increased signal intensity of the normal C8 nerve roots (arrows)
Upward traction on the brachial plexus can result in isolated lower plexus deficits that manifest as paralysis of the hand only. This pattern is known as Klumpke palsy.
Schwannoma of the superior trunk. (a) Sagittal T1-weighted image, arrow points to the tumor which is located in the superior trunk just lateral to the interscalene triangle and above the subclavian artery (SA). MSM, middle scalene muscle. (b) Coronal T1-weighted image with intravenous gadolinium shows the enhancing tumor (arrow).
Large schwannoma originating from the root C8. (a) Sagittal T1-weighted image shows the tumor in the superior sulcus and interscalene triangle. The subclavian artery (SA) and anterior scalene muscle (ASM) are displaced anteriorly. (b and c) Coronal T2-weighted image (b) and axial T1-weighted image (c) show the extension of the tumor into the intervertebral foramen C7-T1 (arrows).
Ganglioneuroma of the sympathetic chain. (a) sagittal T1-weighted image with intravenous gadolinium demonstrates an inhomogeneously enhancing tumor extending into the superior sulcus and interscalene triangle. The tumor encases root T1, and abuts root C8 and the subclavian artery (SA). ASM, anterior scalene muscle; MSM, middle scalene muscle. (b and c) Coronal (b) and axial (c) T1-weighted image with intravenous gadolinium show the extension of the tumor through the intervertebral foramen (long arrow) into the spinal canal. The spinal cord (short arrow) is shifted to the right.
Described by panoast as he presumably meant the groove of the subclavian artery in the pleural cuff as superior sulcus.
The stellate ganglion is a collection of nerves (sympathetic) found at the level of the sixth and seventh cervical vertebrae (the last vertebra of the neck). The nerves are located in front of the vertebrae. They are part of the sympathetic nervous system and supply the face and arm.
1. Small left Pancoast’s tumor in 60-year-old woman. Coronal T1-weighted image shows small bilobed mass (white arrow) in left lung apex. Note preservation of normal interscalene fat pad (black arrow), which on coronal images has triangular
appearance. Left brachial plexus (arrowhead) is nicely seen.
2. 65-year-old man presenting with left-sided mixed (i.e., motor and sensory) brachial plexopathy of 2 months’ duration. Patient also has history of cigarette smoking and persistent cough that developed 3 weeks earlier. Chest radiography
(not shown) revealed abnormal findings. Coronal T1-weighted image shows large left tumor (arrow); note normal interscalene fat pad on right. Obliteration of this fat by tumor as seen here generally implies invasion of brachial plexus at level of trunks that normally course between scalene muscles in interscalene fat pad.
. NL: lymphomatous infiltration of the peripheral nerves. A 57-year-old man with B-cell Non-Hodgkin lymphoma presented with right C6 radiculopathy. A, Coronal STIR image shows multifocal segment enlargement of the right-sided brachial plexus (white arrows). B, Sagittal contrast-enhanced T1WIFS shows a focal enhancing mass at the C5– 6 neural foramen (arrow). Images obtained after treatment did not show any residual disease (not shown).
Synovial cell sarcoma. (a) sagittal T2-weighted image shows the hyperintense mass with encasement of the subclavian artery (SA). MSM, middle scalene muscle. (b) Coronal T2-weighted image demonstrates the encasement of the upper
brachial plexus (arrow) and the medial displacement of the anterior scalene muscle (ASM).
Nocardia infection in the superior sulcus. a and b: sagittal T1-weighted image without (a) and with (b) intravenous gadolinium show an enhancing mass in the superior sulcus with interscalene triangle invasion (arrow in a). The mass surrounds
the C8 and T1 nerve roots. There is involvement of the enhancing second rib (R2). Surgical biopsy revealed that this mass, which mimics a super sulcus lung tumor, was a nocardia infection. SA, subclavian artery; ASM, anterior scalene muscle; MSM, middle scalene muscle.
Coronal fat-suppressed T2-weighted image shows diffuse thickening and increased signal intensity in the region of the left brachial plexus affecting the trunks, divisions, and cords.
As a general rule, most irradiation-induced brachial plexopathies manifest 5–30 months after treatment (peak period, 10–20 months).
Viral plexitis is more commonly found in men between the ages of 30 and 70 years and resolves 6–12 weeks after presentation without sequelae
Coronal STIR, coronal T1-weighted and postcontrast sagittal fat-saturated T1-weighted images show radiation fibrosis as diffuse
thickening of divisions and cords of brachial plexus. They reveal hyperintense signal on STIR image and reveal moderate enhancement. There
is no focal mass lesion, thus differentiating it from metastases
Metastases from breast carcinoma in 58-year-old woman. Coronal fat-suppressed T2-weighted image shows two masses (large arrows) that are inseparable from underlying right brachial plexus. Divisions and cords of brachial plexus (small
arrow) adjacent to tumors are bright and swollen.
Metastatic infiltration of the brachial plexus from breast carcinoma: Coronal T1 fat-saturated post contrast image demonstrates diffuse enhancement of the brachial plexus (cords and branches). Enhancement of the muscles around the shoulder girdle is suggestive of denervation changes.
Sagittal T1-weighted image with arm in neutral position shows normal costoclavicular space between the clavicle and first rib. Thin arrow depicts clavicle while the thick arrow shows normal subclavian artery.
2. Sagittal T1-weighted images with arm in hyperabduction demonstrating the costoclavicular spaces, respectively. Note decrease in the sizes of the latter two spaces during abduction
1. Sagittal T1-weighted image with arm in neutral position shows normal retropectoralis minor space. Thin arrow shows pectoralis minor muscle. The subclavian artery is depicted by thick arrow. The cords of brachial plexus lie superior to it.
2. Sagittal T1-weighted images with arm in hyperabduction demonstrating retropectoralis minor spaces, respectively. Note decrease in the sizes of the latter two spaces during abduction
Left-sided neurogenic thoracic outlet syndrome. (a) Radiograph shows a cervical rib on the asymptomatic side (small arrow) and a hypertrophic transverse process of C7 on the symptomatic side (long arrow). (b) Coronal T1-weighted image demonstrates that the fibrous band (short arrow), which courses from the hypertrophic transverse process of C7 (long arrow) to the first rib (R1), causes a deviation of the C8 nerve root. (c) Sagittal T1-weighted shows the fibrous band (arrow) within the interscalene triangle. SA, subclavian artery; ASM, anterior scalene muscle.
MIDN (a and b) coronal T1-weighted (a) and T2-STIR (b) image show thickening of the brachial plexus (arrows) with an increased signal intensity on the
T2-weighted images.
MRI: T2-weighted image with short tau inversion recovery (T2W-STIR) (A, C and E–G); T1-weighted spin echo images with
gadolinium-enhancement (B and D)
The spinal nerve roots and their peripheral nerves in the lumbar (A, B, C and D) and brachial plexuses (G) show changes in thickening and were enhanced with gadolinium (arrows in B and D).
Interscalene fat space, costoclavicular region and retro pectoralis minor.