Radiology 2000; 214:73-80
Swenson Stephen J., Viggiano Robert W., Midthun David E., Muller Nestor L., Sherrick Andrew, Yamashita Keiji, Naidich David P., Patz Edward F., Hartman Thomas E., Muhm John R., Weaver Amy L.
PURPOSE: To test the hypothesis that absence of statistically significant lung nodule enhancement (£ 15 HU) at computed tomography (CT) is strongly predictive of benignity.
MATERIALS AND METHODS: Five hundred fifty lung nodules were studied. Of these, 356 met all entrance criteria and had a diagnosis. On nonenhanced, thin-section CT scans, the nodules were solid, 5-40 mm in diameter, relatively spherical, homogeneous, and without calcification or fat. All patients were examined with 3-mm-collimation CT before and after intravenous injection of contrast material. CT scans through the nodule were obtained at 1, 2, 3, and 4 minutes after the onset of injection. Peak net nodule enhancement and time-attenuation curves were analyzed. Seven centers participated.
RESULTS: The prevalence of malignancy was 48% (171 of 356 nodules). Malignant neoplasms enhanced (median, 38.1 HU; range 14.0-165.3 HU) significantly more than granulomas and benign neoplasms (medianm 10.0 HU; range, -20.0 to 96.0 HU; P < .001). With 15 HU as the threshold, the sensitivity was 98% (167 of 171 malignant nodules), the specificity was 58% (107 of 185 benign nodules), and the accuracy was 77% (274 of 356 nodules).
CONCLUSION: Absence of significant lung nodule enhancement (£ 15 HU) at CT is strongly predictive of benignity.