Clinical image: ultrasound findings and magnetic resonance imaging comparison in the muscular involvement in polyarteritis nodosa.

1 Short tau inversion recovery (STIR) sequence MRI (a, b) and ultrasound (c, d) findings in a patient with polyarteritis nodosa showing high concordance of lesions at the rectus femoris (RF), compared to the vastus intermedius (VI), as described in the main text Discussion Muscle involvement in PAN is a rare but well-described condition, and most cases are diagnosed using MRI [[3]]. A magnetic resonance imaging (MRI) was performed to address these findings and revealed that most of the proximal lower limb muscles, notably the left vastus intermedius, presented with a patchy hyperintense appearance on the short tau inversion recovery (STIR) sequence (Fig. [Extracted from the article]