MR imaging of intrahepatic cholangiocarcinoma: use of ferumoxides for lesion localization and extension.

OBJECTIVE: The purpose of this study was to evaluate the use of ferumoxides in the visualization and localization of intrahepatic cholangiocarcinoma. CONCLUSION: The contrast-to-noise ratio of cholangiocarcinoma compared with that of the adjacent liver significantly (p < 0.03) improves after ferumoxides administration. Ferumoxides-enhanced MR imaging is a useful technique for the visualization and localization of intrahepatic cholangiocarcinoma.

Color and power Doppler sonography of liver hemangiomas: a dream unfulfilled?

PURPOSE: The aim of this study was to determine whether color Doppler or power Doppler sonography can aid in the diagnosis of hepatic cavernous hemangiomas. METHODS: We imaged 25 hepatic cavernous hemangiomas in 17 patients with gray-scale, color Doppler, and power Doppler sonography. Five malignant lesions were also imaged in the same manner for reference. Hemangiomas had been previously diagnosed by biopsy in 8 patients (15 lesions) and by CT, MRI, and/or tagged red blood cell scanning in 9 patients (10 lesions). RESULTS: Of the 25 hemangiomas, color or power Doppler imaging showed no internal blood flow in 23. Of these 23 lesions, 11 showed a peripheral flow pattern believed to represent flow in displaced blood vessels. This pattern was better visualized with power Doppler imaging in 3 lesions and equally well visualized with color and power Doppler imaging in 8 lesions. Two hemangiomas that had unusual central fibrosis with large vessels in 1 patient showed diffusely increased blood flow on power Doppler study. All 5 malignant lesions showed flow in peripheral vessels, and 1 showed internal vascularity as well. CONCLUSIONS: Neither color nor power Doppler imaging improved the capability of sonography for making a specific diagnosis of benign hepatic cavernous hemangioma.

MR imaging in the evaluation of hepatic metastases.

Optimal detection of focal hepatic lesions in patients with metastases can alter patient management and result in significant cost savings by reducing the number of unnecessary laparotomies for unresectable disease. Liver-specific MR imaging contrast agents (reticuloendothelial and hepatobiliary agents) offer greater lesion-to-liver contrast than the conventional extracellular fluid space MR imaging contrast agents (gadolinium chelates), which have a nonspecific distribution. For the detection of hepatic metastases, although the work of Seneterre et al suggests that the accuracy of ferumoxide-enhanced MR imaging is equivalent to that of CTAP, other studies find CTAP to be superior. Comparisons of reticuloendothelial agents and hepatobiliary agents for imaging liver metastases are lacking in the literature. Further studies comparing MR imaging enhanced with liver-specific contrast agents to CTAP are needed to determine if hepatic MR imaging can replace CTAP for the preoperative evaluation of hepatic metastases. For the characterization of focal liver lesions, MnDPDP and ferumoxides have been added to the small list of FDA-approved contrast agents, and both can help to increase diagnostic specificity. Two of the hepatobiliary agents which are not yet approved, Gd-BOPTA and Gd-EOB-DTPA, have the potential of characterizing liver lesions during dynamic contrast enhancement (similar to Gd-DTPA) and during the hepatocyte phase (similar to MnDPDP), and may increase the detection of focal liver lesions.

Muramyl peptide/serotonin receptors in brain-derived preparations.

Certain peptidoglycans (muramyl peptides), components of bacterial cell walls, and the monoaminergic neurotransmitter serotonin, profoundly modulate some activities of mammalian immune and nervous systems. We previously described the interaction of these compounds at receptors on macrophages. This report concerns specific binding sites for muramyl peptide in preparations of brain tissue, interaction between muramyl peptide and serotonin in binding to glial-derived cells, and the ability of both muramyl peptide and serotonin to induce release of interleukin-1-like activity from these cells. Specific binding sites for muramyl peptides in the low-nanomolar concentration range were found on subcellular fractions of fresh rat brain preparations, e.g., from diencephalon, and C6 glioma cells. This binding was saturable, reversible, stereospecific, and varied with brain region. In addition, muramyl peptide blocked the specific component of serotonin binding to glioma cells, while leaving the nonspecific binding component unaffected. Interleukin-1 has previously been shown to be released by macrophages in response to muramyl peptide. We found that low-nanomolar concentrations of either muramyl peptide or serotonin rapidly induced release of interleukin-1-like activity from a glial cell line. Thus, the pyrogenic and sleep-promoting effects of muramyl peptide may be mediated at least in part by release of interleukin-1 in the brain that follows binding to muramyl peptide/serotonin receptors on glial cells.