[Intravenous urography has been the gold standard in diagnostic radiology studying the urogeintal system. However, ultrasound and other cross-sectional imaging methods have brought major change in this area. Beside modern (multislice) CT examinations the methods of MR urography are more frequently applied making possible both static and dynamic examinations beyond the wellknown advantages of MR imaging. The authors describe two complemetary methods of MR urography which provide a complete evaluation of the urinary system. The first method is aimed to image stationary fluid by using heavily T2 weighted turbo spin echo pulse sequences. This measurement well depicts the dilations of the excretory system even with little or no excretion of urine. The second method is analogous with the traditional IVU, as the excretion of a less nephrotoxic gadolinium based contrast medium followed by a T1 weighted gradient echo pulse sequence (possibly dynamic) helps to visualise the renal cavities and the urinary pathways. Normal renal function is a prerequisite when using this technique in order to visualise normal and obstructed urinary pathway disorders. The use of MR urography together with traditional MR methods may significantly reduce the number of invasive examinations and methods based on X-ray radiation exposure. MR urography may be exceptionally important in the uroradiological study of distensions of renal cavities in pediatric cases, pregnant women and renal transplant patients or in case of contrast material allergy.]

[INTRODUCTION - Breast cancer screening was performed in 27 325 female patients at the National Institute of Oncology from 1st of January 2002 to May 30th of 2005. Complementary examinations were necessary in 1876 women. MR-mammography was performed in 65 of these cases. We were curious about in which cases MR mammography helps to make the diagnosis more accurate, how does it influence the therapy. We also studied, whether the number of surgical interventions because of benign breast lesions decreases due to MR mammography. PATIENTS AND METHODS - In 65 patients MR mammography was performed using non-contrast axial and coronal T1W and STIR sequences. After the injection of gadolinium four series of 3D FLASH (fast low angle shot) dynamic gradiens echo sequences were also applied. Subtraction of the non-contrast and contrast enhanced series were evaluated in addition to the intensity curves of the postcontrast series. RESULTS - MR mammography helped to evaluate dense breasts in 21 cases, to identify multifocal lesions in 6 cases and to differentiate the malignant-benign processes. In the course of the 65 post-screening examinations, malignant processes [BI-RADS IV-V (Breast Imaging Reporting and Data System)] were diagnosed in 21 cases, benign processes (BI-RADS II-III) or negative results were found in 44 patients. CONCLUSION - MR mammography increased diagnostic accuracy, decreased the number of benign lesion-related surgical procedures and increased the accuracy in determining surgical radicality and establishing a therapeutic plan.]

[PURPOSE - Evaluation of different gastrointestinal endoluminal contrast materials by using an experimental model. MATERIALS AND METHODS - Authors constructed a plastic container holding six plastic cups, thus making possible to evaluate different compounds and concentrations, simultaneously. The signal intensity of more than 15 different materials (commonly used contrast materials, fruit juices, cocoa, iron containing solutions) was measured by T1 and T2 weighted spin echo sequences in a 1T MR unit. The results were compared in tables and demonstrated by figures. RESULTS - The plastic container and cups made it possible to evaluate the contrast materials by MR examination. The fruit juices containing metallic components had high signal intensity on T1 weighted images, while on the T2 weighted images showed moderate to high signal intensity except the rosehip syrup and a special blackcurrant extract, which were of low signal intensity. Cocoa drink had low to moderate signal intensity on both the T1 and T2 weighted images. The signal intensity of the iron(III)-desferrioxamin solution increased on the T1 weighted images and decreased on the T2 weighted images in direct proportion to its iron concentration. CONCLUSION - The described in vitro model is an appropriate and risk-free solution for selecting the proper endoluminal contrast material, its concentration, and the best measuring sequences for defining the optimal in vivo MR bowel examination protocol. On the base of the experimental results rosehip syrup, blackcurrant extract, iron(III)- desferrioxamin and cocoa drink were selected for further in vitro and in vivo examinations.]

[PURPOSE - Optimization of gradient-echo and spin-echo sequences in order to visualize oral contrast media for magnetic resonance imaging (MRI) of the small bowel using a 1-T unit. MATERIAL AND METHODS - Authors investigated the optimal appearance of four different potential oral contrast media (rosehip syrup, blackcurrant extract, iron(III)-desferrioxamine, cocoa) with different spin-echo and gradientecho sequences using a simple plastic model. They were searching the optimal solution by changing the parameters of the chosen sequences keeping an eye in every case on the signal-to-noise ratio, the contrast, the resolution, the artifacts and the signal intensity of the contrast materials. RESULTS - The gradient-echo sequences are suitable for imaging of the small bowel. Too short echo time should be avoided because of the increased formation of artifacts. A lot of artifacts can be eliminated using fat saturation. T2*- weighted gradient-echo sequences provide good appearance for the cocoa drink, as well as the three-dimensional gradient-echo sequence. The use of sequential gradientecho acquisition methods is advisable only in non-cooperating patients, because of their low signal-to-noise ratio. The iron(III)-desferrioxamine solution, the rosehip syrup and the blackcurrant extract are potential positive contrast agents on T1-weighted sequences. On the single-shot fast spin-echo (SSFSE) sequence the rosehip syrup and the blackcurrant extract appear as negative contrast materials. CONCLUSIONS - Authors could select and optimize the sequences suitable for each contrast material and effective in small bowel MRI. The substances used in their experimental model are not harmful for humans when administered orally, so determination of additives is the only problem remained before their use in the clinical practice.]

[INTRODUCTION - Modern radical radiotherapy can be an effective alternative of radical prostatectomy in low risk patients with prostate tumor. Our objective was to demonstrate the feasibility of transperineal MR-guided prostate interventions in an open MR unit and to present our early clinical experiences on canines. METHODS AND MATERIALS - The procedures were performed on 5 canines in an open-configuration 0.35T MR scanner. For interventions an MR compatible custom-made device was used. The canines were placed in the right lateral decubitus position. Template reconstruction, trajectory planning, target and OAR delineation were based on T2 FSE images. For image guidance and target confirmation, fast spoiled gradient-echo (FSPGR) sequence was used. MR compatible coaxial needles were inserted through the perineum to the base of the prostate. After satisfactory position was confirmed, brachytherapy catheters were placed through the coaxial needles, which were then removed. RESULTS - Mean and standard deviation of the needle displacements was 2.2 mm±1.2 mm, with a median of 2 mm. 96% of the errors were less than 4.0 mm. Implantation induced prostate motion was measured with a mean of 10.3 and 2.3 mm in cranio-caudal and transverse directions. Significant movement was only observed during the first 4 needle insertions. The average time needed for each step was: anesthesia 15 minutes, setup and positioning 15 minutes, initial imaging 15 minutes, template registration and projection 15 minutes, contouring, trajectory planning, insertion of 10 needles 60 minutes. CONCLUSION - Based on our canine model experiences our method seems to be a promising approach for performing feasible, accurate, reliable and high-quality prostate MR guidance within a reasonable time span. We plan to introduce MR-guided biopsy and brachytherapy in human patients in the near future.]