Einsatz der Niederfeld-Extremitäten-Magnet-Resonanz-Tomographie (E-MRT) in der Frakturdiagnostik : Untersuchungen zu Durchführbarkeit, Kosten und Stellenwert

Study objectives: A dedicated low-field MRI was investigated regarding the costs and the diagnostic value in detecting acute fractures of the distal extremities compared to conventional x-ray. Material and methods: 236 patients with the clinical suspicion of a fracture at the distal extremities were primarily examined by 0,2T low-field-MRI (Artoscan?, Esaote, Italy). After that a conventional radiography and a clinical follow up was done. Secondly X-ray and MRI examinations of 78 patients with „save diagnosis“ were separated (41 positive diagnosis, 37 without fracture). Both methods were independently analyzed by two experienced radiologists in regard of the existence of a fracture. In addition the type of fracture was analyzed. The interobserver-variability was calculated for both methods. Results: The costs for a low-field MRI examination were calculated to 100-120$instead of 10-15$ for a conventional x-ray examination. For the detection of acute fractures of the distal extremities low-field MRI yielded an accuracy of 81.4%, versus 79.5% for x-ray-examination. MRI was less accurate in the detection of small anatomic structures such as fingers or digits. Intraosseous lesions can not be adequately imaged by x-ray examination. Concerning the interobserver-variability both methods had to be rated as ”moderate”. Conclusions: For detecting acute fractures of the distal extremities the accuracy of low-field MRI and conventional x-ray examinations are almost equivalent. The primary non-selective use of a low-field MRI for detecting acute fractures instead of conventional x-ray seems not to be reasonable

Nicotine and Arteriosclerosis

Peer Reviewe

Enhancement of liver parenchyma after injection of hepatocyte-specific MRI contrast media: a comparison of gadoxetic acid and gadobenate dimeglumine

PURPOSE: To compare enhancement of liver parenchyma in MR imaging after injection of hepatocyte-specific contrast media. MATERIALS AND METHODS: Patients (n = 295) with known/suspected focal liver lesions randomly received 0.025 mmol gadoxetic acid/kg body weight or 0.05 mmol gadobenate dimeglumine/kg body weight by means of bolus injection. MR imaging was performed before and immediately after injection, and in the delayed phase at approved time points (20 min after injection of gadoxetic acid and 40 min after injection of gadobenate dimeglumine). The relative liver enhancement for the overall population and a cirrhotic subgroup was compared in T1-weighted GRE sequences. An independent radiologist performed signal intensity measurements. Enhancement ratios were compared using confidence intervals (CIs). RESULTS: The relative liver enhancement in the overall population was superior with gadoxetic acid (57.24%) versus gadobenate dimeglumine (32.77%) in the delayed-imaging phase. The enhancement ratio between the contrast media was statistically significant at 1.75 (95% CI: 1.46-2.13). In the delayed phase, the enhancement of cirrhotic liver with gadoxetic acid (57.00%) was comparable to that in the overall population. Enhancement with gadobenate dimeglumine was inferior in cirrhotic liver parenchyma (26.85%). CONCLUSION: In the delayed, hepatocyte-specific phase, liver enhancement after injection of gadoxetic acid was superior to that obtained with gadobenate dimeglumin