Application of anatomically shaped surface coils in MRI at 0.5 T.

The construction and application of eight different MRI surface coils is described. The coils consist of an anatomically shaped copper wire loop as an antenna and a printed circuit board containing electronic components for tuning and matching. The electronic device for tuning and matching is interchangeable between the various coils. Surface coils for signal detection yield images with high signal-to-noise ratio in comparison to the usual saddle-shaped head or body coils. The sensitivity of a surface coil decreases with increasing distance between the coil and the object of interest and therefore the coils are constructed to fit the anatomical structure under examination as well as possible. The application of dedicated surface coils for superficial structures in the body extends the possibilities of the MRI system. Photographs of the coils positioned on the body and MR images of volunteers and patients are shown.

An improved saddle coil for MR imaging in resistive magnet systems.

The design of a two-turn radiofrequency coil for MR imaging at 0.15 T is presented. The use of well-isolated copper tube (instead of the usual wire) as conductor material resulted in an open, patient friendly construction. Furthermore, the Q value and signal-to-noise ratio of the tube-type coil were increased as compared to the corresponding values in the case of a geometrically similar wire-type coil.

Combined dynamic studies of the bladder and urethra. Report of a method.

The authors report a method of complex urodynamic investigation. The intravesical pressure, the intrarectal pressure, the electronically computed detrusor pressure, the urinary flow and the electromyography of the anal and urethral striated sphincters are recorded simultaneously with the fluoroscopic image on 16 mm film using the kinescopic procedure. The intravesical pressure is measured per urethram. The routine examination method is described. The authors consider that the use of 16 mm film has advantages in comparison to videotape recordings. The installation was made out of existing materials except for the electronic mixing device, which was created in the research laboratory. Radiation dosis measurements show that even by extensive examination the received radiation dosis does not exceed the exposure of a standard voiding cystourethrogram.