Results of electrochemical therapy of colorectal liver metastases in rats followed up by MRI.

Rationale And Objectives: Direct-current or electrochemical therapy is an alternative method for local tumor therapy. Until recently, it was mainly applied in China and was relatively unknown in the Western world. This study examines the feasibility and effectiveness of applying direct-current therapy in liver metastases of colorectal carcinomas in an animal model.

MRA in patients with cerebrovascular disease. Considerations of clinical effectiveness.

Objective: To establish in which clinical contexts cerebral MR angiography (MRA) is routinely carried out in a neurological university department and to describe its clinical impact.

Material And Methods: Medical records, reports of findings and documentation of imaging examinations carried out in all 69 patients referred to the Department of Radiology from the Department of Neurology between 1995 and 1998 for cerebral MRA were evaluated. The clinical impact of all imaging findings was assessed on the basis of the medical records.

Magnetic resonance sialography.

To evaluate a new noninvasive sialographic technique, we applied a new magnetic resonance technique to 10 healthy volunteers and 21 patients with lesions of the parotid gland. In addition to the usually performed T(1) and T(2) cross-sectional sequences, a heavily T(2)-weighted sequence (TR = 3600 msec, TE = 800 msec) was performed that allowed depiction of the fluid-filled parotid duct system. Twenty-one patients with benign as well as malignant parotid gland pathologies were examined: sialadenitis (n = 6), sicca syndrome (n = 2), pleomorphic adenoma (n = 4), carcinoma of the parotid gland (n = 2), lymphoepithelial carcinoma (n = 1), cystadenolymphoma (n = 3), non-Hodgkin's lymphoma (n = 2), and congenital duct dilatation (n = 1).

MR cholangiography in children with autosomal recessive polycystic kidney disease.

Background: Magnetic resonance cholangiography (MRC) is a relatively new, non-invasive imaging technique of the biliary tree that has shown good correlation with endoscopic retrograde cholangiopancreatography. The liver manifestation of autosomal recessive polycystic kidney disease (ARPKD) is congenital hepatic fibrosis (CHF). CHF may be accompanied by Caroli's disease, which is characterised by a non-obstructive dilation of the intrahepatic bile ducts.

[MR-compatible and conventional marker wires in breast diagnosis--experimental studies on their dislocatability and artifact size in MRT].

Purpose: Localization of non-palpable suspicious breast lesions with tumor localization wires is commonly used before surgical excision. Dislocation of the wire is possible. The possibility of dislocation for different types of tumor localization wires was examined experimentally.

Fast and ultrafast magnetic resonance imaging in renal lesions.

Our purpose was to analyze and compare the image quality and contrast-to-noise ratio (CNR) of different fast T1- and T2-weighted sequences with conventional spin-echo sequences in renal MRI. Twenty-three patients with focal renal lesions were examined with a T2-weighted ultrafast turbo spin-echo (UTSE) sequence with and without frequency selective fat suppression (SPIR), a combined gradient-and-spin-echo sequence (GraSE), and a conventional spin-echo sequence (SE). In addition, T1-weighted images were obtained pre- and postcontrast, using a fast spin-echo sequence (TSE) with and without SPIR and the conventional SE sequence.

Absolute metabolite quantification by in vivo NMR spectroscopy: IV. Multicentre trial on MRSI localisation tests.

The difference between the experimental and theoretical spatial response function (SRF) of a narrow tube with water is used for a localization test for magnetic resonance spectroscopic imaging (MRSI). From this difference a quantitative performance parameter is derived for the relative amount of signal within a limited region in the field of view. The total signal loss by the MRSI experiment and eddy currents is described by a parameter SL derived from the signal intensities of two echoes.

Absolute metabolite quantification by in vivo NMR spectroscopy: II. A multicentre trial of protocols for in vivo localised proton studies of human brain.

We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility.

Proton MR spectroscopy in infants with cerebral energy deficiency due to hypoxia and metabolic disorders.

Purpose: To investigate the similarities and differences of cellular energy deficiencies due to asphyxia and to impaired oxidative phosphorylation caused by enzyme deficiencies using localized 1H-MR spectroscopy of the brain.

Material And Methods: In 35 neonates and infants with a postconceptional age of 36.4-153 weeks, 1H-MR spectra were obtained from the basal ganglia.

Influence of the hepatobiliary contrast agent mangafodipir trisodium (MN-DPDP) on the imaging properties of abdominal organs.

To assess the influence of Mangafodipir Trisodium on the imaging properties of abdominal organs when using T1-weighted gradient-echo (GE) and T2-weighted turbo spin-echo (TSE) sequences, thirty patients with focal lesions in the liver were examined at a field strength of 1.5 T before and after intravenous administration of Mangafodipir Trisodium (dose: 5 micromol/kg of body weight). Administration of Mangafodipir Trisodium led to a significant increase in the signal intensity of the liver tissue (p < 0.

High-resolution MR imaging of the cutis and subcutis. Histological correlation.

Objective: To determine whether the spatial resolution that can be achieved with currently available MR devices is adequate for the evaluation of skin disease.

Material And Methods: We correlated high-resolution MR images of the skin with dermatohistopathology in 26 patients. The examinations were carried out on a 1.

[Direct-current treatment of chemically induced mammary carcinoma in an animal model: MR volumetric assessment of the effect of the therapy].

Purpose: To investigate the effect of direct current treatment (DCT) on the growth of mammary carcinomas in rats by MR-volumetry.

Methods: Chemically induced mammary adenocarcinomas in a control group (n = 17) were compared with treated tumours (18 C/cm3 in group A: n = 7 or 36 C/cm3 in group B: n = 12). 31 untreated tumours were situated near a treated tumour (group C).

[Endorectal MRI and ultrasonography in rectal tumors: correlation with histological staging].

Purpose: To compare the accuracy of high resolution endorectal magnetic resonance imaging (EMRI) and endorectal ultrasound (EUS) in the preoperative diagnostic of rectal tumours.

Patients And Methods: Twenty-one patients with known rectal tumours underwent MR imaging with an endorectal surface coil and EUS. Transversal EMR images were obtained using fast T2-weighted sequences and pre- and postcontrast T1-weighted images.

[Correlation of MRI and histopathological findings in inflammatory skin diseases].

Purpose: Can spatial and contrast resolution be achieved with currently available MR devices for the successful assessment of inflammatory diseases of the skin?

Method: High resolution MRI was performed in 20 patients with non-malignant diseases of the dermis and subcutis. The skin biopsies subsequent to the MR examinations were indicated for clinical reasons. The MR examinations were done in the location of later performed skin biopsies using a 1.

Detection of focal hepatic lesions: effects of superparamagnetic iron oxide (AMI-25) on magnetic resonance imaging of the liver using T2-weighted fast spin-echo sequences and gradient-and-spin-echo sequences at 1.0 tesla.

Rationale And Objectives: The authors evaluate the value of two fast spin-echo sequences (FSE) with different T2-weighting (repetition time [TR]/echo time [TE] = 2000/90 mseconds and TR/TE = 2000/40 mseconds) and combined gradient-and-spin-echo sequences (TR/TE = 2000/90 mseconds) for contrast-enhanced liver imaging with superparamagnetic iron oxide (AMI-25).

Methods: Forty-seven patients with focal liver lesions underwent magnetic resonance imaging at 1.0 tesla.

[Localization of puncture needles in MRI: experimental studies on precision using spin-echo sequences at 1.0 T].

Purpose: To evaluate accuracy of needle localisation using and signal enhancement on a 1.OT MR imager for various needles for MR-guided biopsy.

Methods: The differences between actual and virtual needle position of needles with different orientations were evaluated in a phantom for spin-echo including turbo-spin-echo sequences.

Localized 31P MR spectroscopy of the transplanted human kidney in situ shows altered metabolism in rejection and acute tubular necrosis.

The purpose of this study was to investigate the function of transplant kidneys in situ, and to detect pathologic changes, using volume-selective phosphorous NMR spectroscopy (31P MRS). Localized 31P MR spectra were obtained from 37 patients using a whole-body MR scanner with a combination of surface coils, adiabatic excitation pulses, and a modified image-selected in vivo spectroscopy (ISIS) sequence. Seventeen patients with pathologic changes after renal transplant were compared with a control group of 20 patients with no evidence of transplant dysfunction.

MR sialography: initial experience using a T2-weighted fast SE sequence.

Purpose: The aim of this study was to evaluate an MR technique optimized for imaging of the parotid gland ductal system.

Method: The pulse sequence was optimized in 10 volunteers to depict static or nearly static fluid in the parotid ductal system. A heavily T2-weighted fast SE sequence (TR 3,600 ms/TE 800 ms) with a slice thickness of 30-40 mm using an 8 cm surface coil allowed depiction of the fluid-filled parotid duct.

[31P-MR spectroscopy of the human liver--the spectral indications of lymphoma infiltration].

Purpose: To evaluate whether phosphorus magnetic resonance spectroscopy (31P-MRS) enables a non-invasive detection of liver involvement in systemic diseases like Hodgkin's lymphoma.

Materials And Methods: Using a clinical 1.5 Tesla whole-body MR system image-guided localised phosphorus MR spectra from the anatomically defined volumes of interests were measured.

Prospective comparison of fast SE and GRASE sequences and echo planar imaging with conventional SE sequences in the detection of focal liver lesions at 1.0 T.

Purpose: Our goal was to investigate the value of T2-weighted fast SE (FSE) sequences, FSE sequences with shortened echo spacing (UFSE), combined gradient and spin echo sequences (GRASE), and segmented T1-weighted echo planar imaging (EPI) in comparison with conventional SE sequences in the detection of focal liver lesions.

Method: Thirty-five patients with malignant focal liver lesions underwent MRI at 1.0 T.

Quantitative measurements with localized 1H MR spectroscopy in children with Canavan's disease.

Canavan's disease is an autosomal recessive hereditary leukodystrophy resulting from deficiency of the enzyme aspartoacylase. Two children suffering from this metabolic brain disease were examined using image-guided localized proton spectroscopy. The absolute concentrations of metabolites were determined.

[Comparison of fast turbo-spin-echo and gradient- and spin-echo sequences as well as echo planar imaging with conventional spin-echo sequences in MRI of focal liver lesions at 1.0 tesla].

Purpose: To evaluate the value of rapid T2-weighted turbo-spin sequences (TSE), turbo-spin-echo sequences with shortened echo spacing (UTSE), gradient-and-spin-echo sequences (GraSE) and T1-weighted echo-planar imaging (EPI) in comparison with conventional spin-echo sequences (SE) in the diagnosis of focal liver lesions.

Methods: 20 patients with malignant focal liver lesions underwent magnetic resonance imaging at 1.0 tesla.