Impact of iso- and low-osmolar iodinated contrast agents on BOLD and diffusion MRI in swine kidneys.

PURPOSE: To assess whether functional MR imaging using blood-oxygenation level-dependent (BOLD) imaging and diffusion-weighted imaging demonstrate changes in renal oxygenation and apparent diffusion coefficient (ADC) in a pig model. MATERIALS AND METHODS: After administration of either 1-g iodine/kg body weight low-osmolar iopromide or iso-osmolar iodixanol, 8 mini pigs underwent a series of repeated BOLD measurements (TR/TE 106/5.9-48.7 ms, slice thickness 4 mm) and diffusion-weighted imaging measurements (TR/TE 3900/79 ms, slice thickness 4 mm) for 1 hour at 1.5 T. In this intraindividual cross over study, the second contrast agent injection with the other iodinated contrast agent was performed at least 24 hours after the initial contrast agent injection. BOLD-based R2* values as indirect measures of the renal oxygenation were determined for the cortex, the inner medulla, and the outer medulla. ADC values were measured for the cortex and the whole kidney. RESULTS: For both contrast agents, a drop in R2* was found in the cortex, which normalized after 55 minutes. In the outer medulla and particularly in the inner medulla, a decreased initial drop of R2* was encountered with both contrast agents, with a slow increase toward the baseline R2*. In the inner medulla, elevated R2* values were found with the iso-osmolar contrast agent only. The ADC revealed an initial increase, which slowly decayed over the measurement period. This finding was more pronounced for the cortex compared with the whole-kidney analysis. CONCLUSION: Functional MR imaging of the kidneys demonstrates increased R2* in the inner medulla only after the administration of the iodixanol potentially indicating hypoxia and thus a pathomechanism of contrast-induced nephropathy.

Effective second-line treatment with cetuximab and bevacizumab in a patient with hepatic metastases of colorectal cancer and hyperbilirubinemia.

BACKGROUND: Irinotecan-based second-line chemotherapy of metastatic colorectal cancer (CRC) is effective, it might, however, be contraindicated in cases of severe liver dysfunction due to advanced liver metastases. CASE REPORT: A 57-year-old woman with diffuse CRC liver metastases showed progressive disease on first-line treatment with capecitabine and oxaliplatin (XELOX). Chronic cholestasis and hyperbilirubinemia caused by advanced liver involvement prohibited second-line treatment with irinotecan-based chemotherapy. We initiated combined antibody treatment with cetuximab and bevacizumab. RESULTS: Clinical performance status as well as laboratory parameters improved rapidly. Staging investigations after 8 weeks revealed a partial remission. Since bilirubin levels had returned to the upper limit of normal, therapy could be changed to standard irinotecan, 5-fluorouracil, folinic acid, and bevacizumab. CONCLUSION: Combined treatment with cetuximab and bevacizumab may be considered as an effective treatment option in patients who cannot be treated with standard chemotherapy regimens due to impaired liver metabolism of cytotoxic substances.