Frequent cause of the Macklin effect in spontaneous pneumomediastinum: demonstration by multidetector-row computed tomography.

OBJECTIVE

The purpose of this study was to evaluate the Macklin effect in patients with spontaneous pneumomediastinum by multidetector-row computed tomography (MDCT).

METHODS

Chest computed tomography (CT) reports between July 2000 and January 2003 at our institution were retrospectively reviewed. Nine patients with spontaneous pneumomediastinum were identified, and their CT scans were evaluated to detect the Macklin effect. The patient diagnoses included interstitial lung diseases (n=4), bronchiolitis obliterans organizing pneumonia or pneumonia (n=3), asthma (n=1), and spontaneous pneumomediastinum without definite pulmonary disease (n=1).

RESULTS

The Macklin effect was observed in 8 (89%) of 9 patients. In 4 patients, the Macklin effect was observed in perihilar and peripheral areas, and in 4 patients, it was observed only in the perihilar area.

CONCLUSIONS

The Macklin effect can frequently be demonstrated in patients with spontaneous pneumomediastinum of nontraumatic respiratory causes by MDCT. A CT-proven Macklin effect may be useful in differentiating respiratory from other causes of pneumomediastinum.