RöFo : Fortschritte auf dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
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Comparative Study
[Cardiac MR tagging: optimization of sequence parameters and comparison at 1.5 T and 3.0 T in a volunteer study].
The aim of this study was the optimization of a gradient echo (GRE) MR tagging sequence at 3.0 T in comparison to 1.5 T in order to obtain the best image contrast between the myocardium, tag lines and blood signal. Theoretically expected improvements of signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were also calculated. ⋯ Myocardial tagging at 3.0 T has shown superior image quality in comparison to 1.5 T due to a higher baseline SNR and an improved CNR as well as RCMT. The suppressed fading of the tags enables the accessibility to the diastolic phase of the cardiac cycle.
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Review Comparative Study
[Hydration for the prevention of contrast medium-induced nephropathy: an update].
Contrast medium-induced nephropathy (CIN) continues to be one of the most common causes of hospital-acquired acute renal failure. Since most of the clinical studies on the prophylactic use of different drugs to prevent CIN produced disappointing results, hydration remains the mainstay of prophylaxis. A number of recent prospective randomized trials provided further evidence of the effectiveness of hydration and relevant information regarding the optimization of hydration protocols. ⋯ Another hydration protocol, which could also be very attractive especially for outpatients, included the infusion of sodium bicarbonate. In a recent trial, hydration with sodium bicarbonate, given as a bolus for 1 hr. prior to examination followed by an infusion for 6 hrs. after examination, was more effective than hydration with sodium chloride for the prophylaxis of CIN. However, there is still a lack of large-scale, multi-center trials comparing different hydration protocols and investigating their influence on clinically relevant endpoints such as mortality or the need for dialysis.
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Comparative Study
[Initial results of shoulder MRI in external rotation after primary shoulder dislocation and after immobilization in external rotation].
A change in the strategy for treating primary anterior traumatic dislocation of the shoulder has occurred. To date, brief fixation of internal rotation via a Gilchrist bandage has been used. Depending on the patient's age, a redislocation is seen in up to 90 % of cases. This is due to healing of the internally rotated labrum-ligament tear in an incorrect position. In the case of external rotation of the humerus, better repositioning of the labrum ligament complex is achieved. Using MRI of the shoulder in external rotation, the extent of the improved labrum-ligament adjustment can be documented, and the indication of immobilization of the shoulder in external rotation can be derived. The aim of this investigation is to describe the degree of position changing of the labrum-ligament tear in internal und external rotation. ⋯ In anterior labrum-ligament tears, the axial MRI of the shoulder in external rotation demonstrates a more physiologic position of the glenoid. This may indicate an immobilization of the shoulder in external rotation, which results in a more anatomical healing of the glenoidal tear. Thus, in the case of labrum-ligament tears, MRI in external rotation is becoming indispensable.
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Comparative Study
[Value of diffusion-weighted imaging for diagnosing vertebral metastases due to prostate cancer in comparison to other primary tumors].
Several publications have reported that the apparent diffusion coefficient is generally lower in metastatically affected vertebrae. Therefore, metastases are represented in diffusion-weighted images by increased signal intensity in comparison to unaffected vertebrae. However, there were indications that metastases due to prostate cancer may differ from this. Therefore, the contrast behavior of vertebral metastases due to prostate cancer or tumors with another histology are to be systematically studied using diffusion-weighted images. The present study is intended to examine whether the two groups differed and whether possible differences depended on the degree of sclerosis. ⋯ In general, the metastatically affected vertebrae appear hyperintense in the diffusion-weighted images. This observation is only true for some vertebral metastases due to prostate cancer. The cause for this seems to be the degree of sclerosis of the metastases. Thus, it cannot be generally deduced from the hypointensity in diffusion-weighted images that a lesion is benign.