Lateral cavity wall thickening as an early radiographic sign of mycetoma formation

The sensitivity of chest radiography for the early detection of mycetoma fo rmation within fibrotic cavities is poor. The purpose of this study was to determine the predictive value of the secondary sign of lateral cavity wall thickening for the detection of a radiographically occult mycetoma. The ch est radiographs and CT scans of 70 patients who had a total fibrotic caviti es on CT were reviewed by two observers. Dimensions of the cavity, mycetoma , and wall thickness on chest radiography and CT were recorded Mycetomas we re visible in 41 of 99 cavities on chest radiographs and in 61 of 109 cavit ies on CT. Using CT as the gold standard for detecting presence of mycetoma s, the sensitivity of chest radiography for the presence of a mycetoma was 62% and the specificity 94%, and the positive and negative productive value s were 93 and 66%, respectively On logistic regression analysis, lateral wa ll thickness on chest radiography was predictive of the presence of a mycet oma (p < 0.0005) indepent of other radiographic features. In patients with chronic fibrocavitary disease on chest radiography, the presence of lateral wall thickening is highly suggestive of an underlying mycetoma.