Figure 5b. Parsonage-Turner syndrome (acute brachial neuritis). (a) Oblique coronal fast spin-echo T2-weighted fat-suppressed MR image (3,000/63) shows marked high signal intensity throughout the supraspinatus muscle (S) and in the deltoid muscle (arrow). (b) Oblique sagittal fast spin-echo T2-weighted fat-suppressed MR image (3,000/70) (anterior to the left) shows that in addition to the high signal intensity in the supraspinatus and deltoid muscles, the infraspinatus and teres minor (arrow) muscles are involved. This diffuse edema pattern is characteristic of a neurogenic deficit involving both suprascapular and axillary nerves.