Jef Huyskens, MD

Jan L Gielen, MD PhD

PERIPHERAL NERVES

IMAGING

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

ANATOMY

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

PATHOPHYSIOLOGY

• Compressive:

• Entrapment

• Nerve Instability

• Non-compressive:

• Traumatic

• Tumors and tumor like conditions

• Inflammation

• Infection: leprosy

• Miscellaneous

MECHANISMS OF PERIPHERAL NERVE INJURIES

• Mechanical-acute disruption of continuity

• Laceration

• Stretch

• Intraneural injection

• Arterial vascular occlusion

• Acute ischemia: vasa nervora

• Pressure

• Extraneural: entrapment neuropathy, fibrosis

• Intraneural: injection ischemia, hemorrhage in nerve sheath, fibrosis

• Compartment syndrome

• Chemical

• Injection of neurotoxic solutions

CLASSIFICATION

Seddon Sunderland Structural and functional

processesRecovery

Neurapraxia 1Myelin damage, conduction

slowing, and blockingBlunt trauma: 6 months

Axonotmesis 2Loss of axonal continuity,

endoneurium intact, no conduction

Interruption axons, intact nerve

sheath: axonal regeneration 1

mm/day

Neurotmesis

3

Loss of axonal and endoneurial

continuity, perineurium intact, no

conduction

Interruption fascicles and sheath:

Wallerian degeneration, axonal

regeneration or neuroma formation

4

Loss of axonal, endoneurial, and

perineurial continuity; epineurium

intact; no conduction

5Entire nerve trunk separated; no

conduction

Based on data from Seddon, Sunderland, and Lundborg

CLASSIFICATION

Seddon Sunderland Structural and functional

processesRecovery

Neurapraxia 1Myelin damage, conduction

slowing, and blockingBlunt trauma: 6 months

Axonotmesis 2Loss of axonal continuity,

endoneurium intact, no conduction

Interruption axons, intact nerve

sheath: axonal regeneration 1

mm/day

Neurotmesis

3

Loss of axonal and endoneurial

continuity, perineurium intact, no

conduction

Interruption fascicles and sheath:

Wallerian degeneration, axonal

regeneration or neuroma formation

4

Loss of axonal, endoneurial, and

perineurial continuity; epineurium

intact; no conduction

5Entire nerve trunk separated; no

conduction

Based on data from Seddon, Sunderland, and Lundborg

CLASSIFICATION

Seddon Sunderland Structural and functional

processesRecovery

Neurapraxia 1Myelin damage, conduction

slowing, and blockingBlunt trauma: 6 months

Axonotmesis 2Loss of axonal continuity,

endoneurium intact, no conduction

Interruption axons, intact nerve

sheath: axonal regeneration 1

mm/day

Neurotmesis

3

Loss of axonal and endoneurial

continuity, perineurium intact, no

conduction

Interruption fascicles and sheath:

Wallerian degeneration, axonal

regeneration or neuroma formation

4

Loss of axonal, endoneurial, and

perineurial continuity; epineurium

intact; no conduction

5Entire nerve trunk separated; no

conduction

Based on data from Seddon, Sunderland, and Lundborg

CLASSIFICATION

Seddon Sunderland Structural and functional

processesRecovery

Neurapraxia 1Myelin damage, conduction

slowing, and blockingBlunt trauma: 6 months

Axonotmesis 2Loss of axonal continuity,

endoneurium intact, no conduction

Interruption axons, intact nerve

sheath: axonal regeneration 1

mm/day

Neurotmesis

3

Loss of axonal and endoneurial

continuity, perineurium intact, no

conduction

Interruption fascicles and sheath:

Wallerian degeneration, axonal

regeneration or neuroma formation

4

Loss of axonal, endoneurial, and

perineurial continuity; epineurium

intact; no conduction

5Entire nerve trunk separated; no

conduction

Based on data from Seddon, Sunderland, and Lundborg

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

ULTRASOUND

• Identifying and localisation of morphologic changes in peripheral nerves:

• nerve rupture

• inflammatory processes

• compressive syndromes

• tumoral lesions

• Testing of motor nerve function: muscle contraction

• Alternative to EMG

• Does not test for the functional (sensorial) capacity of the nerve: combined with nerve conduction study

• Muscle morphology: volume reduction and increased reflectivity

• Initial imaging of a suspected peripheral nerve injury or for follow-up imaging for

superficial nerves (< 2cm)

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

MRI

• Nerve: acute axonal disease

• T2: High SI

• Increased cross section distal to compression

• Muscle denervation mapping on axial images: nerve identification and location

• T2-WI (FS) - STIR

• Acute and subacute: >24h -< 3 weeks

• Muscle edema

• T1 WI:

• involution

• > 3 weeks

• Lipomatous infiltration

• Volume reduction

• Gadolinium enhancement

• 24h after injury

CONTENT

• Anatomy

• Pathophysiology

• Ultrasound

• MRI

• Cases

Zenuw Wortel Spieren

n. dorsalis scapulae C5 mm. rhomboideus en m. levator scapulae

n. thoracicus longus C5-C7 m. serratus anterior

n. subclavius C5-C6 m. subclavius

n. suprascapularis C5-C6 m. supraspinatus en m. infraspinatus

n. pectoralis lateralis C5-C7 m. pectoralis major (door contact met n. pectoralis medialis)

n. musculocutaneus C5-C7 m. coracobrachialis, m. brachialis en m. biceps brachii

laterale wortel van de n. medialis C5-C7 vezels naar de n. medialis

n. subscapularis superior C5-C6 bovenste deel m. subscapularis

n. thoracodorsalis C6-C8 m. latissimus dorsi

n. subscapularis inferior C5-C6 Onderste deel m. subscapularis en m. teres major

nervus axillaris C5-C6 voorste tak: m. deltoideus en een smal gebied van de overliggende huid.

achterste tak: m. teres minor and m. deltoideus

n. radialis C5-T1 m. triceps brachii, m. supinator, m. anconeus, de extensoren van de onderarm en m. brachioradialis

n. pectoralis medialis C8-T1 m. pectoralis major en pectoralis minor

middelste wortel van de n. medialis C8-T1 vezels naar de n. medialis

n. cutaneus brachii medialis C8-T1 -

n. cutaneus antibrachii medialis C8-T1 -

n. ulnaris C8-T1 m. flexor carpi ulnaris, de 2 mediale buiken van de m. flexor digitorum profundus, groot gedeelte van de kleine handspieren

Zenuw Wortel Spieren

n. dorsalis scapulae C5 mm. rhomboideus en m. levator scapulae

n. thoracicus longus C5-C7 m. serratus anterior

n. subclavius C5-C6 m. subclavius

n. suprascapularis C5-C6 m. supraspinatus en m. infraspinatus

n. pectoralis lateralis C5-C7 m. pectoralis major (door contact met n. pectoralis medialis)

n. musculocutaneus C5-C7 m. coracobrachialis, m. brachialis en m. biceps brachii

laterale wortel van de n. medialis C5-C7 vezels naar de n. medialis

n. subscapularis superior C5-C6 bovenste deel m. subscapularis

n. thoracodorsalis C6-C8 m. latissimus dorsi

n. subscapularis inferior C5-C6 Onderste deel m. subscapularis en m. teres major

nervus axillaris C5-C6 voorste tak: m. deltoideus en een smal gebied van de overliggende huid.

achterste tak: m. teres minor and m. deltoideus

n. radialis C5-T1 m. triceps brachii, m. supinator, m. anconeus, de extensoren van de onderarm en m. brachioradialis

n. pectoralis medialis C8-T1 m. pectoralis major en pectoralis minor

middelste wortel van de n. medialis C8-T1 vezels naar de n. medialis flexoren, pronator

n. cutaneus brachii medialis C8-T1 -

n. cutaneus antibrachii medialis C8-T1 -

n. ulnaris C8-T1 m. flexor carpi ulnaris, de 2 mediale buiken van de m. flexor digitorum profundus, groot gedeelte van de kleine handspieren

CASES UPPER LIMB

• Brachial plexus

• Suprascapular nerve

• Radial nerve

• Median nerve

• Ulnar nerve

SUPRASCAPULAR NERVE

• C5-C6

• Superior trunk brachial plexus

• Transverse scapular ligament

• Suprascapular foramen

• Supraspinatus fossa

• Inferior transverse ligament

• Infraspinatus muscle

RADIAL NERVE

• N. Radialis:

• Precubital

• Humerus fracture mid diaphysis

• Cubital: vague forearm pain, no muscle dysfunction

• Radial tunnel syndrome (RTS)

• N. Interosseus posterior (PIN):

• Postcubital compression

• Arcade Frohse, tumor, bursa, cyst, fibrosis (radial head FX)

• N. Radialis, superficial sensory branch

• Wrist: Wartenberg syndrome

ULNAR NERVE

• Cubital Tunnel Syndrome (2nd most frequent compressive neuropathy)

• Ulnar nerve impingement at cubital tunnel

• Activity – mechanism

• baseball, jackhammer, boxers, javelin throwers

• Imaging findings

• US and MRI: detect anomalies at the cubital tunnel: ganglia, bone spurs and musculus anconeus accessorius

• Position of the ulnar nerve relative to the medial epicondyle is evaluatied during flexion and extention movement on US

MEDIAN NERVE

• Elbow:

• Struthers Ligament

• Pronator teres syndrome

• AINS (Kiloh nevin)

• Lacertus fibrosus

• Supracondylar humerus fracture

• Carpal Tunnel Syndrome

• >20mm: pathologic, 10-20mm?, < 10mm: normal

• Caliber jump

• Persistent median artery

• Accessory muscle belly

CASES LOWER LIMB

• Lumbar plexus

• Femoral nerve

• Sacral plexus

• Sciatic nerve

LOWER LIMBS

• N. Ischiadicus

• Hematoma

• Lipoma

• N. Peroneus communis

• Fibula compression

• (Intraneural) Cyst, fracture, dislocation, cast

• N. Suralis

• N. Tibialis, N. plantaris medialis et lateralis

• N. Interdigitalis

• Bursa, fibrosis: Morton neuroma

TAKE HOME MESSAGES

• What do I want to see?

• Ultrasound: entrapment, nerve thickening

• MRI: denervation edema – mapping

• MRI spine

• Several entrapment syndromes

• Cubital tunnel U

• Ulnar nerve dislocation U

• Guyon tunnel U

• PIN – Frohse arcade R

• Pronator M

• Carpal tunnel M

• Tarsal tunnel T