31P MR spectroscopy to evaluate the efficacy of hepatic artery embolization in the treatment of neuroendocrine liver metastases.

Background: It is common to treat patients with metastatic disease from gastrointestinal neuroendocrine (NE) tumors with surgical reduction to prolong survival. This can be combined with hepatic arterial embolization (HAE) and medical treatment to reduce hormonal symptoms. Today there are no rapid and reliable methods to evaluate the efficacy of HAE in the treatment of neuroendocrine liver metastasis.

Contrast agent influences MRI phase-contrast flow measurements in small vessels.

Contrast-enhanced MR angiography is often combined with phase contrast (PC) flow measurement to answer a particular clinical question. The contrast agent that is administered during contrast-enhanced MR angiography may still be present in the blood during the consecutive PC flow measurement. The aim of this work was to evaluate the influence of contrast agent on PC flow measurements in small vessels.

Quantitative phase-contrast flow MRI measurements in the presence of a second vessel closely positioned to the examined vessel.

Purpose: To examine the influence of the truncated sampling of k-space data on the accuracy of phase-contrast (PC) flow quantifications in the presence of nearby vessels.

Materials And Methods: Computer simulations were performed along with some experimental validations on a flow phantom and a normal subject.

Results: The accuracy of the PC flow quantification decreased when a second vessel was positioned closely to the examined vessel.

The magnitude of signal errors introduced by ISIS in quantitative 31P MRS.

It is well known that the quality of a quantitative 31P MRS measurement relies largely on the performance of the volume selection method, and that image selected in vivo spectroscopy (ISIS) suffers from contaminating signal caused mostly by T1 smearing. However, these signal errors and their magnitude are seldom addressed in clinical studies. The aim of this study was therefore to investigate the magnitude of signal errors in 31P MRS when using ISIS.