Atypical small hemangiomas of the liver: "Bright dot" sign at two-phase spiral CT

PURPOSE: To determine if a tiny enhancing dot is characteristic of small hemangiomas with low attenuation during the hepatic arterial phase (HAP) and portal venous phase (PVP) of two-phase spiral computed tomography (CT). MATERIALS AND METHODS: Among 249 consecutive patients with 377 hemangiomas who underwent two-phase spiral CT (performed 30 and 65 seconds after the start of injection), 34 hemangiomas in 20 patients were less than 2 cm in diameter, had low attenuation during the HAP and PVP, and showed characteristic findings on dynamic contrast material-enhanced magnetic resonance (MR) images. The CT scans were retrospectively reviewed for tiny enhancing dots and correlated with the MR images. RESULTS: Tiny enhancing dots were found in 26 of 34 hemangiomas (76%). The dots were seen during the HAP and PVP in 15 lesions (58%) and during the PVP alone in 11 lesions (42%). The lesions showed a tendency toward slow fill-in at MR imaging (only four lesions completely filled with contrast materials within 5 minutes). The dots seen at CT corresponded to the initial enhancing area at MR imaging. CONCLUSION: Small hemangiomas with persistent low attenuation at two-phase spiral CT can be diagnosed with the "bright spot" sign.