imaging sequences obtained in brachial plexopathy with/without TOS MR Imaging Sequences Associated Anatomic Structures or Pathologic Conditions

Transcription

1 Brachial plexus

2 imaging sequences obtained in brachial plexopathy with/without TOS MR Imaging Sequences Associated Anatomic Structures or Pathologic Conditions Sagittal TSE T2WI through cervical spine Spinal cord lesion (edema, hemorrhage, avulsion, myelomalacia, syrinx, t etc) Precontrast axiala T1WI BPL (thickening, nodularity) Precontrast coronalb T1WI BPL, vertebrae, long C7 transverse process, cervical rib Axiala 2D TSE T2WI BPL (thickening, nodularity, signal changes better seen between anterior and middle scalene muscles), radiculopathy, diskopathy, foraminal invasion, spinal cord lesions, large sized pseudomeningocele, muscle denervation Coronalb STIR T2WI BPL (any signal changes not detectable on 2D TSE T2WI, especially in traction injuries and brachial plexitis), muscle denervation in traumatic injury, and brachial plexitis Axiala 3D TSE heavily T2WI (MR myelography) Root avulsions, small sized pseudomeningocele, which can be miss 2D TSE T2WI. Postcontrast fat saturated axiala T1WI BPL (contrast enhancement), contrast enhancement of root stump or intra roots or denervated muscles in preganglionic injuries Postcontrast coronalb T1WI BPL (contrast enhancement) Sagittalc,d T1WI from the symptomatic side in abduction Compression on BPL and subclavian vessels (positional, cervical rib, long C7 transverse process, accessory muscles, fibrous band) Sagittalc,d T1WI from the symptomatic side in neutral if there is compression Resolution of compression on the BPL and subclavian vessels MRAc and MRVc of subclavian artery and vein in abduction Subclavian artery and vein (patency, thrombosis, aneu any impingement on the vessels) MRAc and MRVc of subclavian artery and vein next day in neutral if there is impingement Resolution of impingement on the subclavian vessels

3 Causes accidents avulusioninjuries obsteritic shoulder dislocation tumour

4 Types of lesion Brachial plexus lesions can be divided into three types: An upper brachial plexus lesion, which occurs from excessive lateral neck flexion away from the shoulder. Most commonly, forceps delivery or falling on the neck at an angle causes upper plexus lesions leading to Erb's palsy. This type of injury produces a very characteristic sign called Waiter's tip deformity due to loss of the lateral rotators of the shoulder, arm flexors, and hand extensor muscles. Less frequently, the whole brachial plexus lesion occurs;

5 most infrequently, sudden upward pulling on an abducted arm (as when someone breaks a fall by grasping a tree branch) produces a lower brachial plexus lesion, in which the eighth cervical (C8) and first thoracic (T1) nerves are injured "either before or after they have joined to form the lower trunk. The subsequent paralysis affects, principally, the intrinsic muscles of the hand and the flexors of the wrist and fingers".this results in a form of paralysis known as Klumpke's paralysis

6 Seddon classification Neurapraxia: The mildest form of nerve injury. It involves an interruption of the nerve conduction without loss of continuity of the axon. Recovery takes place without wallerian degeneration Axonotmesis: Involves axonal degeneration, with loss of the relative continuity of the axon and its covering of myelin, but preservation of the connective tissue framework of the nerve (the encapsulating tissue, the epineurium and perineurium are preserved). Neurotmesis: The most severe form of nerve injury, in which the nerve is completely disrupted by contusion, traction or laceration. Not only the axon, but the encapsulating connective tissue lose their continuity. The most extreme degree of neurotmesis is transsection, although most neurotmetic injuries do not produce gross loss of continuity of the nerve but rather, internal disruption of the nerve architecture sufficient to involve perineurium and endoneurium as well as axons and their covering. It requires surgery, with unpredictable recovery.

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