High-resolution ultrasound and MRI in the evaluation of the forefoot and midfoot.

Abstract

Radiography is the appropriate initial imaging modality to assess for midfoot and forefoot pathology before turning to advanced imaging techniques. While most lesions of the mid- and forefoot can be diagnosed clinically, the exact nature and severity of the pathology is often unclear. This review addresses the use of the ultrasound, as well as the added value of magnetic resonance imaging, in diagnosing conditions of the midfoot and forefoot. Ultrasound allows a dynamic assessment as well as enabling imaging-guided interventions for diagnostic and therapeutic purposes. Practical tips for optimal examination of this area with ultrasound and magnetic resonance imaging are provided. Metatarsal stress fracture, Chopart's injury, Lisfranc injury, as well as the 1st metatarsophalangeal joint injury and lesser metatarsophalangeal plantar plate injury are injuries unique to the mid- and forefoot. The imaging anatomy of the 1st and lesser metatarsophalangeal joints is reviewed, as such knowledge is key to correctly assessing injury of these joints. Characteristic imaging features of masses commonly encountered in the mid- and forefoot, such as ganglion cyst, Morton neuroma, gouty tophus, plantar fibroma, foreign body granuloma, and leiomyoma are reviewed. The use of ultrasound and magnetic resonance imaging in assessing degenerative and inflammatory joint disorders, and in particular rheumatoid arthritis, of the mid- and forefoot region is also reviewed. In summary, when necessary, most lesions of the mid-and forefoot can be adequately assessed with ultrasound, supplemented on occasion with radiographs, computed tomography, or magnetic resonance imaging.