PMC8297480_01
3T magnetic resonance neurography in a 21-year-old male with COVID-19-related acute respiratory distress syndrome and right radial nerve palsy and left shoulder weakness noted after extubation. A) Sagittal oblique T2W FS MR image of the shoulder demonstrates diffuse muscle oedema of the infraspinatus (shorter arrow), supraspinatus (longer arrow), and anterior deltoid muscles (arrowhead). B) Coronal maximal intensity projection reformatted image from a thin-section, large field-of-view coronal 3D STIR SPACE sequence of the brachial plexus shows extensive, asymmetric left brachial plexus oedema of the C5 nerve root extending into the superior trunk (shorter arrows), the C6 nerve root, the suprascapular nerve (arrowhead), and the axillary nerve (longer arrow). The patient had motor deficits of the anterior and lateral deltoid muscles and the supraspinatus and infraspinatus muscles, which corresponded to axillary and suprascapular nerve deficits. C) Coronal large field-of-view T1W FS postcontrast magnetic resonance image of the brachial plexus depicts enhancement of the C5 nerve root only as it extends to the superior trunk (arrow). This corresponded to the findings from electrodiagnostic studies
PJR-86-44682-g001.jpg
PMC8297480_01_PJR-86-44682-g001.jpg
F1
Subsequently, a left brachial plexus MRN was performed to better assess the regional peripheral nerves (Figure 1), which showed extensive left C5 and C6 nerve root oedema extending to the superior trunk, anterior and posterior divisions, and the posterior cord.
PMC8297480_02
3T magnetic resonance neurography in a 61-year-old male with COVID-19-related acute respiratory distress syndrome and new-onset left shoulder weakness noted after extubation. A) Coro nal large field-of-view STIR MR image that includes both shoulder girdles demonstrates bilateral shoulder girdle muscle and fascial oedema that is symmetric in distribution but slightly worse on the left (arrow indicates subscapularis diffuse muscle oedema). Post-contrast imaging also showed muscle and fascial enhancement (not shown). Incidental note is made of dependent right upper lobe signal abnormality (arrowhead), which corresponds to lung parenchymal consolidation. B) Coronal large field-of-view STIR MR image of the brachial plexus on both sides shows asymmetric oedema of the left musculocutaneous nerve (arrow). The brachial plexus nerves themselves were not thickened or oedematous. This shows the benefit of large field-of-view imaging that includes both sides for comparison. C) Coronal large field-of-view postcontrast T1W FS MR image of the brachial plexus on both sides shows asymmetric enhancement of the left musculocutaneous nerve (arrow). Incidental note is made of bilateral subacromial/subdeltoid synovitis and left shoulder synovitis, which can contribute to shoulder pain but should not lead to shoulder weakness. D) Axial T2W FS MR image of the left upper arm redemonstrates thickening and oedema of the musculocutaneous nerve (arrowhead) and shows biceps brachii diffuse muscle oedema (arrow), corresponding to weakness with elbow flexion, which was the patient's most pronounced deficit on physical examination
PJR-86-44682-g002.jpg
PMC8297480_02_PJR-86-44682-g002.jpg
F2
Cervical spine MRI did not reveal clear findings of impingement that would explain the patient's deficits, and left brachial plexus MRN was performed (Figure 2).
PMC8297480_03
1.5 T magnetic resonance neurography in a 37-year-old male with COVID-19-related acute respiratory distress syndrome and new-onset right distal lower extremity weakness and foot drop noted after extubation. A) Axial STIR large field-of-view magnetic resonance (MR) image of the lumbosacral plexus shows asymmetric right sciatic nerve thickening at the level of the ischial tuberosity (smaller arrow). There is adjacent focal quadratus femoris muscle oedema (arrowhead) and medial, bilateral gluteus maximus muscle oedema (longer arrows). These were of uncertain aetiology but could be related to pressure given the locations. B) Axial T1W NFS large field-of-view MR image of the lumbosacral plexus demonstrates asymmetric right sciatic nerve thickening and effacement of interfascicular fat (arrow) compared with the normal left side (arrowhead). C) Axial T1W FS post-contrast large field-of-view MR image of the lumbosacral plexus reveals sciatic nerve enhancement (shorter arrow) at the ischial tuberosity level that corresponds to oedema seen on the STIR sequence, and correlates to the site of the patient's suspected neuropathy based on clinical findings. The quadratus femoris muscle exhibits peripheral enhancement (arrowhead), which could represent focal myonecrosis. The medial gluteus maximus muscles are mildly enhancing as well (longer arrows)
PJR-86-44682-g003.jpg
PMC8297480_03_PJR-86-44682-g003.jpg
F3
Because no focal radicular impingement was seen on lumbar spine MRI, lumbosacral plexus MRN was performed (Figure 3) and showed focal sciatic nerve oedema and enhancement at the level of the ischial tuberosity.