Comparative study of vascular enhancement on post-contrast CT using three dosages of iodinated contrast media for the aim of detecting brain metastasis in patients with lung cancer

Abstract

A prospective double-blind randomized study was performed to compare the contrast of vascular enhancement using three dosages of iodinated contrast media for a possible metastatic lesion in the brain. Sixty-six patients with lung cancer received brain computed tomography (CT) with intravenous administration of iodinated contrast medium (CM). The patients were randomly assigned to receive one of the three types of CM: 30 g iodine, 24 g iodine, and 15 g iodine. Three radiologists judged the degree of vascular contrast enhancement and diagnosed the presence of brain metastasis. The CT numbers in major arteries were also measured. The subjective average scores with standard deviation were 2.06+/-0.48, 1.97+/-048, and 1.44+/-0.43, and the measured average CT numbers with standard deviation (SD) were 168.5+/-39.6, 166.1+/-28.6, and 146.1+/-27.0 HU with 30 g, 24 g, and 15 g iodine, respectively. The scores and the CT numbers in 15 g iodine were less than those with 30 g and 24 g iodine. Brain metastasis was detected in one patient each in groups A and C, and one false-positive case was found in group B. CT study with a dose of 24 g iodine showed equivalent quality on vascular enhancement in comparison with a 30 g iodine dose.