Coupling effects in volume selective 1H spectroscopy of major brain metabolites.

The effect of PRESS and STEAM sequences on the spectra of coupled substances are discussed using the examples of weakly coupled AX and A2X systems. Maximum differences compared to uncoupled spins occur if the RF pulses are applied to antiphase magnetization. In this case, the spin echo of the PRESS experiment shows a modified dependence on the refocusing flip angle, which may lead to an attenuation of the acquired signal.

[The visualization of heart wall motion using MR-interferography].

MR interferography provides a method for noninvasive measurement of heart wall motion. An interferographic pattern is projected on short axis views of the left ventricle, characterising local motion of the myocardium. In contrast to tagging methods, interferography images the direction and velocity of local wall motion at the moment of acquisition directly.

Double-volume 1H spectroscopy with interleaved acquisitions using tilted gradients.

A method is presented by which volume selective in vivo 1H spectra of two different voxels can be acquired in an interlaced mode using PRESS or STEAM spectroscopy. Spatially tilted gradients are employed for voxel definition so as to avoid mutual saturation. Independent volume selective shimming of the voxels is possible.

[Magnetic resonance tomography in the diagnosis of peripheral joints].

Magnetic resonance imaging (MRI) provides an excellent soft tissue contrast with high spatial resolution. Using spin echo and fast gradient echo sequences all relevant joint structures such as the hyaline cartilage, the meniscus, the ligaments, the tendons, the capsulae, and their adjacent muscles and their pathology are visualized. Diagnosis of osteonecrosis, meniscal and cruciate ligament lesions, as well as tumors, represents the major current indication for MRI.

RARE-MR-urography in the diagnosis of upper urinary tract abnormalities in children.

RARE-MR-urography (Rapid Acquisition with Relaxation Enhancement) is a fast MR imaging technique (6.4 s/acquisition) that selectively depicts fluid by heavy T2-weighting. From 9/1989 to 11/1990, RARE-MR urograms were prospectively evaluated in the diagnosis of upper urinary tract abnormalities in 55 children.

[Evaluation of iodine levels in daily dietary intake and urine of persons participating in epidemiological studies in the Krakow macro-region after the disaster in Czernobyl and level of iodine in drinking water of that region].

Following the Czernobyl accident, an epidemiologic study was undertaken in which the daily iodine intake was estimated in 15% of the population studied. Iodine excretion was measured in single morning urine specimens. The iodine content was also assessed in the water form wells and in cow-milk at farms in randomly chosen villages in the region of Krynica and Nowy Sacz.

Generalized MR interferography.

Generalized MR interferography allows the measurement of parameters which affect the phase of the MR signal. Interference is generated by the simultaneous generation of two echoes in one excitation cycle. Local variations of the signal phase are transformed into displacement of the stripe pattern generated by interference.

Rheumatoid arthritis lesions of the wrist examined by rapid gradient-echo magnetic resonance imaging.

Alterations of magnetic resonance imaging (MRI) relaxation time and intensity can be helpful in the diagnosis of rheumatoid arthritis (RA) lesions like synovial infiltration, local inflammation and exudation. Fast low angle shot magnetic resonance imaging (FLASH-MRI) is a rapid method showing anatomy and inflammatory pathology of the examined joint comparable to late spin echo T2 images. The following study presents our results of FLASH-MRI wrist examinations of 15 patients suffering from RA according the ARA criteria and 10 healthy volunteers compared to T1 and T2 weighted MR-images and conventional X-rays.

Measurement of CSF flow using an interferrographic MR technique based on the rare-fast imaging sequence.

A fast MR sequence based on the RARE-myelographic technique allows the determination of cerebrospinal fluid (CSF) flow with a flow sensitivity below 1 mm/sec. The method averages flow over the ECG cycle and consequently measures net flow rather than ECG-dependent flow variations. The noninvasivity of this technique and the very short acquisition time of about 5 sec make this sequence a very useful diagnostic tool for a variety of CSF-flow dependent disorders like the determination of different types of hydrocephalus, the control of shunt operations and the assessment of communication pathways between CSF and cysts.

The importance of the voxel size in clinical 1H spectroscopy of the human brain.

It is demonstrated that it is possible to acquire two volume selective 1H NMR spectra of human brain in vivo, consisting of voxels of 1.5 X 1.5 X 1.

[Study of the degree of discrepancies between analytical and theoretical results of the evaluation of daily food rations].

Thirty-six daily food rations given as the basic diet to children in two paediatric hospitals in the City of Cracow were analysed. Using laboratory methods in these meals the contents were analysed of protein, fat and carbohydrates and the energy value was determined. Parallelly the theoretical values++ of these parameters were calculated using "Tables of Composition and Nutritional Value of Food Products".

[Predictive value of magnetic resonance tomography in comparison with sonography and computed tomography in the diagnosis of focal liver lesions].

Ultrasonography and computed tomography are widely used for the diagnosis of focal lesions of the liver. However, the possibilities for tumor characterization and determination of potential malignancy are limited in many cases. Evaluation by magnetic resonance imaging shows a good correlation of relaxation time with the amount of stroma as a proportion of the total cell content of a lesion.

Clinical applications and methodological developments of the RARE technique.

The RARE technique is an extremely useful tool for clinical diagnosis, since it delivers images comparable to those produced by X-ray myelography and X-ray urography. Contrary to these methods, RARE does not use the application of contrast agents. A low-flip-angle variant called FLARE (fast low angle refocused echo imaging) makes this technique accessible for high-field systems.

Fast and exact flow measurements with the fast Fourier flow technique.

The fast Fourier flow technique offers a convenient way for extremely exact flow measurements. In combination with ECG gating, arterial flow can be studied. The total acquisition time for a single measurement is about 10 s, an ECG-gated cine sequence can be acquired in about 4 min.

[Dual-photon absorptiometry: a new method of determining bone mineral content. I. Basic principles].

Today dual-photon absorptiometry (DPA) is recommended as the best procedure for diagnosing osteoporosis at an early stage considering its low cost, low radiation exposure and reasonable reliability. Cortical (neck of femur) and trabecular (L 2-4) bone mass has been determined repeatedly with DPA using 153Gd (NOVO Lab 22 a) in 545 females and 112 males with no evidence of bone diseases. Measured "normal" (age- and sex-related average) values for bone mineral content (BMC) differed significantly (p less than 0.

Quantitative flow measurement with the fast Fourier flow technique.

The fast Fourier flow method of magnetic resonance (MR) imaging offers a fast and efficient way of measuring quantitative flow for velocities within the range from several millimeters per second to more than 1 m/sec. When fast Fourier flow imaging is used in combination with echocardiographic gating, arterial flow can be determined and velocity versus time profiles can be generated. Because of the high spatial resolution, down to 0.

[Initial clinical experiences with RARE-MR urography].

Potentials and limitations of a new, facultative non-tomographic Fast-Imaging sequence "RARE-MR-Urography" are presented. Its results in urological diseases are discussed on the basis of a pilot study of 35 patients. The images (4 s-32 s acquisition time) are extremely T2-weighted and display unbounded free water (urine).

Fast three-dimensional imaging of cerebrospinal fluid.

The RARE method is based on the principle of echo imaging to generate images with high T2 contrast. Since RARE is a fast imaging method, it can be used to acquire a high-resolution three-dimensional data set in less than 15 min. Thin slices from such a three-dimensional data set provide detailed information about the ventricular system.

[MR of the urinary tract in pregnancy].

A report on the application of standard 2D-FT MR combined with RARE-MR-Urography in a pregnant woman with right sided abdominal pain, dilated upper urinary tract and possible stone or inflammatory disease. This technique visualised the complete obstructed ureter in relation to the surrounding organs (uterus, vessels), allows precise diagnosis of the cause of the obstruction and avoids ionising radiation.

MR imaging of flow using the steady state selective saturation method.

The steady state selective saturation method is a fast and efficient technique to study flow with magnetic resonance imaging. The pulse sequence used generates no signal from stationary matter and simultaneously optimizes signal flowing into a predetermined volume. The method can be used to generate three-dimensional angiography in less than 5 min.

[Nuclear magnetic resonance tomography of the sacroiliac joint. A new examination technic in the differential diagnosis of rheumatic diseases of the lumbosacral transition].

25 patients with the clinical diagnoses of possible sacroiliitis were investigated by Magnetic Resonance Tomography (MR). Using axial or coronal tomography in a T1-weighted sequence (7 slices, 1 echo, NEX: 2, slice thickness 8 mm, TR: 600 ms, TE: 33 ms) and in a T2-weighted sequence (7 slices, 4 echos, NEX: 2, slice thickness 8 mm, TR: 1800 ms, TE: 33, 66, 99, 132 ms) we found normal sacroiliac joints in 10 patients, in 12 patients we diagnosed a sacroiliitis, in 3 patients a sacroiliac sclerosis. Descriptive evaluation and T2-calculation we showed, that MR is specific in differentiation of inflammation from sclerosis.

[RARE-MR urography: a fast nontomographic imaging procedure for demonstrating the efferent urinary pathways using nuclear magnetic resonance].

RARE-MR-Urography is a new fast data acquisition technique for magnetic resonance imaging. As a non-tomographic approach to the morphology of the urinary system, image information is similar to intravenous X-ray urography. As the sequence results in a heavily T2-weighted image displaying aqueous fluids, application of contrast agents is not necessary.

Fat and water separation at 0.23 T using simultaneous shift selective imaging.

Based on the principle of selective inversion of the fat or water signal, we have developed a method which allows the simultaneous acquisition of separated fat and water images. In combination with multiecho techniques, this allows the determination of shift selective relaxation times. A detailed analysis of the relaxation behavior of a human leg at 0.