Role of contrast-enhanced dynamic CT in the diagnosis of active tuberculoma.

STUDY OBJECTIVES To assess the role of contrast-enhanced dynamic CT in the diagnosis of active tuberculoma. SETTING Hospitals with an isolated ward for tuberculosis. METHODS Fifty-five subjects with newly diagnosed active tuberculoma and 24 subjects with inactive tuberculoma were examined and evaluated retrospectively. Six subjects with active tuberculomas and seven subjects with inactive tuberculomas were confirmed by histologic and microbiologic evaluation of resected specimens, whereas the remainder of the subjects with tuberculoma were confirmed clinically. The subjects were receiving iopamidol, 370 mg/mL IV, at a rate of 3.0 mL/s on contrast-enhanced dynamic CT. The time-attenuation curve was obtained and adapted to a gamma function. The peak height (PH), maximum attenuation subtracted by the background attenuation, relative flow (RF), and mean regional flow were used for comparison. MEASUREMENTS AND RESULTS In the surgically confirmed group, the PH and RF values of six subjects with active tuberculomas were significantly higher than those of the seven subjects with inactive tuberculoma (p < 0.05). Similarly, in the subjects with noninvasive diagnoses, the PH and RF values of 49 subjects with active tuberculoma were significantly higher than those of the subjects with inactive tuberculoma (mean +/- SD PH, 43.4 +/- 4.1 Hounsfield units [HU] vs 11.6 +/- 2.7 HU, p < 0.0001; RF, 0.012 +/- 0.001/s vs 0.006 +/- 0.001/s, p < 0.05). When the cutoff value was defined as mean +/- 2 SD, the sensitivity and specificity of the diagnosis for active tuberculoma were 77.1% and 96.4% in PH, and 68.5% and 88.8% in RF, respectively. CONCLUSION Contrast-enhanced dynamic CT is a potentially valuable tool for the diagnosis of active tuberculoma.