Computed tomographic contrast enhancement and tumor angiogenesis in canine oral tumors

Abstract

The potential value of bolus tracking contrast enhanced computed tomography (CT) in the diagnosis of oral tumors in dogs was investigated by examining the relationship between contrast-enhanced CT image density and microvascularization. Among 20 dogs with oral tumors, aged 8 – 17 years, weight 3.6 – 40.0 kg, 13 dogs were suffering with melanoma (MM), 4 with squamous cell carcinoma (SCC), and 3 with fibrosarcoma. Based on contrast-enhanced CT scan, the time lag from the injection of contrast medium into the right cephalic vein until the contrast medium returned to the mid-cervical external jugular vein at the level of the 4th cervical vertebrae significantly correlated with body weight (p < 0.01). The mean of post-contrast-enhancement increase in intra-tumor image density, measured in Hounsfield Units (HU), was 127.09 ± 38.58%, with the highest values detected in SCC (166.88 ± 23.47%, p < 0.05), followed by MM (122.78 ± 37.90%) and fibrosarcoma (99.37 ± 31.58%). The mean of microvessel density (MVD, a measure of vascularization determined by vWF-immunohistochemistry) of all tumors was 36.7 ± 11.7 vessels/mm2, with the highest MVD values in SCC (47.5 ± 5.3 vessels/mm2, p < 0.05), followed by MM (35.3 ± 11.6 vessels/mm2) and fibrosarcoma (27.2 ± 6.5 vessel/mm2). The values for MVD and intra-tumor HU in post-contrasted-enhanced CT scans significantly correlated (p < 0.01).