T-one insensitive steady state imaging: a framework for purely T2-weighted TrueFISP.

A new conceptual framework called T-one insensitive steady state imaging is proposed for fast generation of MR images with pure T(2) contrast. This is accomplished by imaging between nonequally spaced inversion pulses, with the magnetization vector alternatively residing in states parallel and antiparallel to B(0) for durations TP(i) and TA(i), respectively. With TP(i) and TA(i) adequately chosen, identical signal time evolution can be obtained for different T(1) values, i.

Sensitive J-coupled metabolite mapping using Sel-MQC with selective multi-spin-echo readout.

The selective multiple quantum coherence technique is combined with a read gradient to accelerate the measurement of a specific scalar-coupled metabolite. The sensitivities of the localization using pure phase encoding and localization with the read gradient are compared in experiments at high magnetic field strength (17.6 T).

Monitoring of tumor oxygenation changes in head-and-neck carcinoma patients breathing a hyperoxic hypercapnic gas mixture with a noninvasive MRI technique.

Purpose: : To implement and evaluate a noninvasive functional MRI technique for measuring tumor tissue oxygenation changes in head-and-neck carcinoma patients.

Patients And Methods: : Tissue oxygenation changes were determined quantitatively in 13 patients with head-and-neck cancer. The MR examinations were performed on a clinical MR scanner at 1.

Potential of magnetization transfer MRI for target volume definition in patients with non-small-cell lung cancer.

Purpose: To develop a magnetization transfer (MT) module in conjunction with a single-shot MRI readout technique and to investigate the MT phenomenon in non-small-cell lung cancer (NSCLC) as an adjunct for radiation therapy planning.

Materials And Methods: A total of 10 patients with inoperable NSCLC were investigated using a 1.5T MR scanner.

Short-echo spectroscopic imaging combined with lactate editing in a single scan.

A short-echo spectroscopic imaging sequence extended with a frequency-selective multiple-quantum- coherence technique (Sel-MQC) is presented. The method enables acquisition of a complete water-suppressed proton spectrum with a short echo time and filtering of the J-coupling metabolite, lactate, from co-resonant lipids in one scan. The purpose of the study was to validate this combined pulse sequence in vitro and in vivo.

Assessment of pulmonary perfusion in a single shot using SEEPAGE.

Purpose: To present a single-shot perfusion imaging sequence that does not require contrast agents or a subtraction of a tag and a control image to create the perfusion-weighted contrast. The proposed method is based on SEEPAGE.

Materials And Methods: Experiments with healthy volunteers were performed to qualitatively and quantitatively obtain pulmonary perfusion values in coronal as well as sagittal orientation.

Quantitative regional oxygen transfer imaging of the human lung.

Purpose: To demonstrate that the use of nonquantitative methods in oxygen-enhanced (OE) lung imaging can be problematic and to present a new approach for quantitative OE lung imaging, which fulfills the requirements for easy application in clinical practice.

Materials And Methods: A total of 10 healthy volunteers and three non-small-cell lung cancer (NSCLC) patients were examined using a 1.5T scanner.

Single-shot quantitative perfusion imaging of the human lung.

The major drawback to quantitative perfusion imaging using arterial spin labeling (ASL) techniques is the need to acquire two images (tag and control), which must be subtracted in order to obtain a perfusion-weighted image. This can potentially result in misregistration artifacts, especially in lung imaging, due to varying lung inflation levels in different breath-holds. In this work a double inversion recovery (DIR) imaging technique that yields perfusion-weighted images of the human lung in a single shot is presented.

Inversion recovery TrueFISP: quantification of T(1), T(2), and spin density.

A novel procedure is proposed to extract T(1), T(2), and relative spin density from the signal time course sampled with a series of TrueFISP images after spin inversion. Generally, the recovery of the magnetization during continuous TrueFISP imaging can be described in good approximation by a three parameter monoexponential function S(t) = S(stst)(1-INV exp(-t/T(*) (1)). This apparent relaxation time T(*) (1) View Article and Find Full Text PDF

Reduced joining of DNA ends correlates with chromosomal instability in three melanoma cell lines.

Chromosomal instability plays a pivotal role in multistep carcinogenesis by facilitating the acquisition of the multiple genetic alterations necessary for malignant transformation. In order to study the role of abnormal DNA repair in malignant melanoma, we measured the ability of cell lines from malignant melanoma and that of primary melanocytes to process 4 different kinds of DNA damage (pyrimidine dimers, oxidative DNA lesions, replication errors, and DNA double-strand breaks) using 4 different plasmid assays. Based on the number of chromosomes, the DNA index, and the rates of spontaneous micronuclei, the chromosomal stability in primary melanocytes and the melanoma line LIBR was characterized as being high, intermediate in M1, and low in MeWo.

Quantitative tissue perfusion measurements in head and neck carcinoma patients before and during radiation therapy with a non-invasive MR imaging spin-labeling technique.

Purpose: Tumor blood flow, tumor tissue perfusion and oxygen supply have substantial influence on the responsiveness of tumors to radiotherapy. This study was aimed at implementing and evaluating a non-invasive functional magnetic resonance (MR) imaging spin-labeling technique at a main magnetic field strength of 2T for measuring tissue perfusion changes in head and neck carcinoma patients before and during radiotherapy.

Methods: Tissue perfusion was determined quantitatively in ten patients with head and neck cancer.