Spontaneous pneumomediastinum and Macklin effect: Overview and appearance on computed tomography

Figure 2 A 21-year-old woman with hypothyroidism and symptoms of cervical discomfort and tenderness. Multidetector-row computed tomography scan demonstrates air collection along the perivascular connective tissue, the Macklin effect (arrows), in the peripheral area (A) and in the perihilar area (B), and pneumomediastinum. Reprinted from ref. [5].