Radiology, Vol 194, 393-398, Copyright © 1995 by Radiological Society of North America
Pulmonary nodules: CT evaluation of enhancement with iodinated contrast material
SJ Swensen, LR Brown, TV Colby and AL Weaver
Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN 55905.
PURPOSE: To determine if the degree of enhancement of pulmonary nodules is
directly related to the likelihood of malignancy and to the vascularity of
the nodule. MATERIALS AND METHODS: Uncalcified 6-40-mm- diameter pulmonary
nodules were studied in 163 patients with malignant neoplasm (n = 111),
granuloma (n = 43), and benign neoplasm (n = 9). Serial thin-section
computed tomography (CT) was performed before and after injection of 100 mL
of nonionic contrast material at 2 mL/sec. The maximum level of enhancement
was recorded. Eighteen histologic specimens were graded after vascular
staining. RESULTS: Malignant neoplasms enhanced (median, 40.0 HU; range,
20-108 HU) significantly more than granulomas and benign neoplasms (median,
12.0 HU; range, -4 to 58 HU) (P < .001). With 20 HU as the threshold for
a positive test, sensitivity was 100%; specificity, 76.9%; positive
predictive value, 90.2%; negative predictive value, 100%; and accuracy,
92.6% (prevalence of malignancy, 68.1%). Degree of enhancement was
significantly related to amount of central vascular staining (P = .003).
CONCLUSION: Enhancement is an indicator of malignancy and vascularity.
