Mapping the biodistribution and catabolism of 5-fluorouracil in tumor-bearing rats by chemical-shift selective 19F MR imaging.

A chemical-shift selective (CHESS) 19F MR imaging technique was used to map selectively the antineoplastic drug 5-fluorouracil (5-FU) and its major catabolite alpha-fluoro-beta-alanine (FBAL) in tumor-bearing rats. The pulse sequence employed a CHESS RF saturation pulse to suppress either the 5-FU or the FBAL resonance before the other component in the two-line 19F MR spectra was measured. Selective 5-FU and FBAL images with a spatial resolution of 10 x 10 x 15 mm3 (1.

19F-[1H] nuclear Overhauser effect and proton decoupling of 5-fluorouracil and alpha-fluoro-beta-alanine.

19F-[1H] magnetic double-resonance experiments were performed on model solutions of the antitumor drug 5-fluorouracil (5-FU) and of alpha-fluoro-beta-alanine (FBAL) in order to improve 19F NMR sensitivity for the application in pharmacokinetic studies in vivo. Upon driving the proton spins into saturation, a fluorine signal enhancement (nuclear Overhauser effect) was observed on the order of the theoretical NOE maximum gamma H/2 gamma F = 53% for purely dipolar coupled 19F-1H spin systems in extreme narrowing. The dependence of the effect on proton excitation frequency and temporal parameters was measured and cross-relaxation rate constants of 0.

Intravenous morphine and nalbuphine increase histamine and catecholamine release without accompanying hemodynamic changes.

Patients receiving intravenous morphine at doses of 0.3 and 1.0 mg/kg for general anesthesia have been reported to show significant elevations in plasma histamine that are associated with hemodynamic changes.

Evaluation of tumour metabolism and multidrug resistance in patients with treated malignant lymphomas.

The management of patients with treated malignant lymphomas requires functional methods to differentiate a residual soft tissue mass. Patients with treated Hodgkin's lymphoma (HL, n = 20, 68 malignant lesions, three benign lesions) or non-Hodgkin's lymphoma (NHL, n = 26, 46 malignant lesions, one benign lesion) were studied with positron emission tomography (PET) and fluorine-18 deoxyglucose (FDG). Oxygen-15 labelled water was used (n = 14, 25 lesions) in addition to FDG in order to obtain information on the tissue perfusion.

Pharmacokinetic mapping of the breast: a new method for dynamic MR mammography.

A dynamic contrast-enhanced MRI technique for whole breast examinations is presented. The fast kinetics of tissue response during and after constant-rate intravenous infusion of gadolinium diethylenetriaminopentaacetic acid was resolved using a strongly T1-weighted saturation recovery TurboFLASH sequence that makes it possible to acquire signal-time courses sequentially from 15 adjacent slices with a temporal sampling rate of 21 s. On the basis of the mathematically established and experimentally verified linear relationship between the measured saturation recovery TurboFLASH signal variation and the gadolinium diethylenetriaminopentaacetic acid concentration in the tissue, the signal-time courses were analyzed within the framework of pharmacokinetic modeling.

Rapid automatic brain volumetry on the basis of multispectral 3D MR imaging data on personal computers.

Fast magnetic resonance imaging sequences are an excellent basis for the volumetry of the human brain. We present a concept for an automatic three-dimensional (3D) segmentation and volumetry which provides rapid image processing along with minimal requirements of manual interaction on low-end hardware platforms. The concept is based on standard image segmentation techniques and provides for the determination of the total brain tissue and cerebrospinal fluid volumes from the input data base, a T1- and a T2-weighted 3D image data cube.

Postprocessing of functional MRI data of motor cortex stimulation measured with a standard 1.5 T imager.

Functional magnetic resonance imaging (fMRI) is usually based on acquisition of alternating series of images under rest and an activation task (stimulus). Brain activation maps can be generated from fMRI data sets by applying several mathematical methods. Two methods of image postprocessing have been compared: (i) simple difference of mean values between rest and stimulation, and (ii) Student's t-test.

Event-related functional MR imaging of visual cortex stimulation at high temporal resolution using a standard 1.5 T imager.

The authors report the technical feasibility of measuring event-related changes in blood oxygenation for studying brain function in humans at high temporal resolution. Measurements were performed on a conventional whole-body 1.5 T clinical scanner with a nonactive-shielded standard gradient system of 1 ms rise time for a maximum gradient strength of 10 mT/m.

Pulsewave velocity measurement using a new real-time MR-method.

A new, one-dimensional method for the measurement of pulsewave velocities using real-time magnetic resonance (MR) imaging is presented. The measurement sequence is essentially of a RACE-type (Real Time Acquisition and Evaluation) with interleaved acquisition in two not necessarily parallel slices. In each slice the blood flow velocity perpendicular to the slice orientation was monitored.

Quantification of regional cerebral blood flow and volume with dynamic susceptibility contrast-enhanced MR imaging.

Purpose: Quantification of regional cerebral blood flow (rCBF) and volume (rCBV) with dynamic magnetic resonance (MR) imaging.

Materials And Methods: After bolus administration of a paramagnetic contrast medium, rapid T2*-weighted gradient-echo images of two sections were acquired for the simultaneous creation of concentration-time curves in the brain-feeding arteries and in brain tissue. Absolute rCBF and rCBV values were determined for gray and white brain matter in 12 subjects with use of principles of the indicator dilution theory.

Granulocyte colony-stimulating factor prophylaxis before operation protects against lethal consequences of postoperative peritonitis.

Background: Postoperative peritonitis has a high mortality in human beings. It is accepted that cytokines are important mediators in pathophysiology of sepsis. The recent failure of clinical trials increased the necessity to proof new drugs in more clinically relevant animal models.

The role of high-dose, single-fraction irradiation in small and large intracranial arteriovenous malformations.

Purpose: Radiosurgery with external beam irradiation is an accepted treatment for small intracranial vascular malformations. It has been proven effective and safe for lesions with volumes of less than 4 cc. However, there is only some limited clinical data for malformations of grade 4 and grade 5, according to Spetzler and Martin.

Functional MR mapping of activated cortical areas.

Magnetic resonance imaging (MRI) has recently been demonstrated to be sensitive to changes in neuronal activity of cortical areas. We report our initial experiences with functional MR brain mapping at high spatial resolution using a conventional whole-body MR system. A total of 10 visual and motor cortex activation studies were carried out on 8 healthy volunteers.

Improved target volume definition for precision radiotherapy planning of meningiomas by correlation of CT and dynamic, Gd-DTPA-enhanced FLASH MR imaging.

In this methodological paper the authors report a fast, T1-weighted gradient-echo sequence (FLASH) for dynamic, Gd-DTPA-enhanced magnetic resonance (MR) imaging of meningiomas and its application in precision radiotherapy planning. Indications for radiotherapy included unresected tumors, tumor remaining after surgery, and recurrences. The patient's head was fixed in a stereotactic localization system which is usable at the CT, MR and the linear accelerator installations.

PET imaging of lung tumours and mediastinal lymphoma.

Positron emission tomography (PET) of the lung is evaluated regarding its clinical practicability for staging of bronchogenic carcinomas and lymphomas. Stringent quality control, optimized acquisition and reconstruction techniques are of crucial importance. An analysis of 50 PET studies for tumour (T) and lymphnode (N) staging in comparison to CT shows that PET has the highest diagnostic accuracy to classify lesions and is the most promising technique for non-invasive staging.

Unknown effects of clinically used drugs as bias in clinical trials: antihistaminergic activity of the antihypertensive fixed-dose combination Betathiazid.

In a controlled clinical trial on histamine release in anaesthesia, it was suspected that the antihypertensive fixed-dose combination drug Betathiazid masked clinical signs of histamine release. By structure analysis of its constituents (propranolol, triamterene and hydrochlorothiazide), hydrochlorothiazide was considered to be most likely an H1-antagonist. An aqueous solution of the whole drug tablet (2 x 10(-4) M propranolol, 2.

Are hypotension and rash after atracurium really caused by histamine release?

A prospective, randomized, double-blind study was performed in 40 patients (ASA class I-III) treated with atracurium to ascertain whether histamine release caused hemodynamic or cutaneous changes. The treated group of 20 patients was premedicated with the H1 antagonist dimetindene (0.2 mg/kg) and the H2 antagonist ranitidine (1.