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K-F Kreitner

Publications and source records attributed to K-F Kreitner.

5 recordsLinked to original sources
PubMed2003

Rapid musculoskeletal magnetic resonance imaging using integrated parallel acquisition techniques (IPAT)--initial experiences.

PURPOSE: To investigate the feasibility of using multiple receiver coil elements for time saving integrated parallel imaging techniques (iPAT) in traumatic musculoskeletal disorders. MATERIAL AND METHODS: 6 patients with traumatic derangements of the knee, ankle and hip underwent MR imaging at 1.5 T. For signal detection of the knee and ankle, we used a 6-channel body array coil that was placed around the joints, for hip imaging two 4-channel body array coils and two elements of the spine array coil were combined for signal detection. All patients were investigated with a standard imaging protocol that mainly consisted of different turbo spin-echo sequences (PD-, T (2)-weighted TSE with and without fat suppression, STIR). All sequences were repeated with an integrated parallel acquisition technique (iPAT) using a modified sensitivity encoding (mSENSE) technique with an acceleration factor of 2. Overall image quality was subjectively assessed using a five-point scale as well as the ability for detection of pathologic findings. RESULTS: Regarding overall image quality, there were no significant differences between standard imaging and imaging using mSENSE. All pathologies (occult fracture, meniscal tear, torn and interpositioned Hoffa's cleft, cartilage damage) were detected by both techniques. iPAT led to a 48 % reduction of acquisition time compared with standard technique. Additionally, time savings with iPAT led to a decrease of pain-induced motion artifacts in two cases. CONCLUSION: In times of increasing cost pressure, iPAT using multiple coil elements seems to be an efficient and economic tool for fast musculoskeletal imaging with diagnostic performance comparable to conventional techniques.

Adolescent↗
PubMed2002

Low-field MR arthrography of the shoulder joint: technique, indications, and clinical results.

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting.

Arthrography↗
PubMed2002

[Preliminary results of coronary artery examination using a 3D-navigator sequence on a high performance MR system].

PURPOSE: To evaluate MR coronary angiography using a three-dimensional navigator echo sequence on a MR scanner with a high performance gradient system. MATERIAL AND METHODS: Five healthy volunteers were examined with a 1.5 Tesla MR system, using a high performance prototype gradient system (peak amplitude 50 mT/m, rising time 600 mus). For imaging, a navigated gradient-echo pulse sequence with an in-plane resolution between 0.63 x 0.63 and 0.78 x 0.78 mm2 was used. Per patient two overlapping slabs were acquired. The number of visualized coronary artery segments was estimated (AHA classification). In addition, signal-to-noise measurements were performed in the ascending aorta at the level of the proximal right and left coronary arteries. RESULTS: In all volunteers the left main, the right coronary artery up to segment 3, the LAD up to segment 8 and the RCX with segment 11 and 13 were clearly visualized. The average signal-to-noise value at the level of the right coronary artery was 11.4 +/- 5.0, at the level of the left coronary artery 12.3 +/- 4.5. One volunteer was measured with an in-place resolution of 0.63 x 0.63 mm2. This resulted in a too low signal-to-noise ratio so that an adequate assessment of coronary arteries was no longer possible. CONCLUSION: 3D-MR coronary angiography using the navigator technique is limited by the signal-to-noise ratio.

Adult↗