Imaging description

The longus colli muscle lies anterior to the cervical spine in the prevertebral space, covered by the prevertebral layer of the deep cervical fascia. It extends from the level of the anterior tubercle of the atlas (C1 vertebra) to the level of the T3 vertebral body in the superior mediastinum. Although the superior tendon fibers at C1–C3 are classically affected in acute calcific tendinitis, theoretically calcific tendinitis could occur in any of the tendon fibers, and there are reports of this process occurring in the inferior tendon fibers as well [1].

Calcific tendinitis of the longus colli was first reported on radiography in 1964 [2]. Although originally reported on radiographs, CT offers improved visualization and localization of the calcium deposits due to its superior spatial resolution. CT and radiographic findings of calcific tendinitis of the longus colli include calcifications anterior to the C1–C3 vertebral bodies with associated soft tissue edema (Figure 23.1A–E). If the calcifications are subtle, however, these may be missed with radiography. Typically MR shows edema, indicating inflammation in and around the longus colli tendon fibers (Figure 23.1F) [3]. A retropharyngeal fluid collection may be seen but should cause smooth enlargement of the retropharyngeal space as opposed to a septic fluid collection (Figures 23.1C, E, F) [4]. As with radiography, the MR depiction of calcifications in fibers of the longus colli muscle is often inferior to CT. Contrast-enhanced cross-sectional imaging may be helpful if fluid collections are present as these will lack wall enhancement, thereby excluding an abscess (Figure 23.1C) [5]. Lack of cervical lymphadenopathy is also a helpful sign to differentiate calcific tendinitis from an infection [1].