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  • 1
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Magnetresonanztomographie ; MRT ; Haut ; In-vivo-Histometrie ; Tumore ; Keywords MRT ; Skin ; Thickness ; Dermatology ; Tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: To characterize human skin qualitatively and quantitatively using high-resolution magnetic resonance tomography (MRT) and to compare skin thickness measurements from MRT and histological specimens. Material and Methods: The skin of 84 persons was examined by use of a 2.5 cm coil in a whole-body tomography (gradient field strength 1.5 T) at a linear resolution of 100 μm. To evaluate the ability to identify various skin structures, following an initial visual description, the signal-noise and contrast-noise ratios were analyzed and the MRT-image compared to the corresponding histological specimen. Results: Using the high-resolution coil, epidermis, dermis and subcutis were discernible. Problem areas included the cheek, distal leg and foot. Reproducible measuring of skin thickness with MRT is possible, but it does not correlate well with conventional histologic measurements.
    Notes: Zusammenfassung Ziel: Anhand von In-vivo-Untersuchungen war die Schnittbildanatomie der Haut hinsichtlich ihrer bislang unbekannten Erscheinung im hochauflösenden Magnetresonanztomogramm (MRT) zunächst qualitativ und quantitativ zu charakterisieren. Anschließend sollte der Wert der MRT hinsichtlich der Hautdickenmessung anhand eines Vergleiches mit histologischen Schnitten analysiert werden. Methodik: In einer prospektiven Studie wurde die Haut von 84 Personen mit Hilfe eines 2,5 cm großen Spulenkopfes in einem Ganzkörpertomographen (Gradientenfeldstärke: 1,5 T) bei einer linearen Auflösung von 100 μm untersucht. Zur Bewertung der Abgrenzbarkeit verschiedener Hautstrukturen wurden nach visueller Charakterisierung deren Signal-Rausch- und deren Kontrast-Rausch-Verhältnisse objektiviert und ein Vergleich mit histologischen Präparaten vorgenommen. Ergebnisse: Mit der Hochauflösungsspule lassen sich Epidermis, Dermis und Subkutis differenzieren (p〈0,05). Problematisch ist dies nur an Wange, distalem Unterschenkel und Fuß. Hautdickenmessungen mit der MRT sind zuverlässig möglich. Die Ergebnisse korrelieren aber nicht mit jenen der Histologie.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2161
    Keywords: Key words Femoral torsion ; Torsional difference ; Ultrasound ; Femoral fractures ; Anterior condylar line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. A torsional difference of more than 15° is found in up to 30% of patients following closed intramedullary nailing of femoral fractures. The diagnosis is usually established postoperatively by computed tomography. A torsional deformity of more than 15° should be corrected by early derotation. In order to enable an intraoperative control and possible correction to avoid a second operation for the patient, a new ultrasound-based method suitable for the intraoperative setting has been developed, using the anterior condylar line as a distal reference line. Design and patients. In a prospective study the torsional difference after closed intramedullary nailing of femoral fractures was measured postoperatively by ultrasound in 32 patients and compared with standard CT readings. Results. Torsional differences measured by ultrasound and CT showed a high correlation (r=0.8) and a median difference of less than ±3°. Conclusions. By the introduction of the anterior condylar line as a distal reference line femoral torsion can accurately be assessed by ultrasound in a position required for intraoperative control and possible correction.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1615-3146
    Keywords: Kerspintomographie ; Kollateralbandruptur ; Knorpelläsion ; Hochauflösende Oberflächenspule ; Magnetic resonance imaging ; Collateral ligament rupture ; Cartilage lesion ; High-resolution coil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Aim of this study was the evaluation of a prototype of a new high-resolution MRI coil for the detection of finger trauma. The practicability of this new coil for the assessment of traumatic lesions of the finger joints and the diagnostic value of this new method in clinical practice was assessed. Twenty patients between 13 and 50 years of age (mean 28 years) were examined with a 1.5-T whole-body-imager Magnetom SP 63 scanner (Siemens, Erlangen, Germany). A prototype of a high-resolution MRI coil with a diameter of 2.5 cm was used. T1- and T2-weighted images with an in plane resolution of 0.I95 x 0.098 mm were acquired. Bone structures, joint cartilage and capsule, ligaments, tendons and soft tissue alterations were assessed. All 19 patients with pathological changes at the finger joints had a joint effusion. With MR imaging, fractures were detected in almost all patients, compared with the X-ray examinations. Cartilage contusion showed high signal intensity. The collateral ligaments could best be assessed in the transversal, and ligament ruptures in the coronal plane. Hemorrhage in the tendon showed an increased signal intensity in T1- and T2-weighted, edema only in T2-weighted images. Especially traumatic lesions of cartilage and of ligaments can be sufficiently assessed by the high-resolution MRI due to its high anatomic resolution compared to common methods like X-ray. High-resolution MRI is practicable in clinical routine.
    Notes: Zusammenfassung Ziel der vorliegenden prospektiven Untersuchung war es, die Wertigkeit der hochauflösenden Kernspintomographie mittels einer speziellen Oberflächenspule in der Beurteilung von traumatischen Veränderungen der Fingergelenke zu evaluieren. Ferner sollte die Praktikabilität der Methode in der klinischen Routine überprüft werden. Es wurden 20 Patienten im Alter zwischen 13 und 50 Jahren (im Mittel 28 Jahre) an einem 1,5-T-Ganzkörpertomographen (Magnetom SP 63, Firma Siemens, Erlangen) untersucht. Als Spule wurde ein Prototyp einer hochauflösenden Oberflächenspule mit einem Durchmesser von 2,5 cm benutzt. T1- und T2-gewichtete Sequenzen mit einer maximalen Auflbsung in der Bildebene von 0,195 x 0,098 mm wurden zur Beurteilung von Knochen, Gelenkknorpel und -kapsel, der Sehnen und des Weichteilgewebes akquiriert. Kernspintomographisch fand sich bei 19 Patienten ein pathologischer Befund. Bei all diesen Patienten konnte ein Gelenkerguß nachgewiesen werden. Knöcherne Absprengungen, die anhand konventioneller Röntgenaufnahmen diagnostiziert wurden, zeigten sich kernspintomographisch als dislozierte signalreiche Strukturen. Gelenkknorpelkontusionen stellten sich hyperintens dar. Zur Beurteilung der Kollateralbānder eignete sich vor allem die koronare Schichtebene, da in dieser die Kollateralbdnder per continuitatem darstellbar sind. Sehneneinblutungen wiesen eine Signalerhöhung in T1- und T2-Wichtung auf. Ödeme der Weichteile und Bandstrukturen imponierten in T2-gewichteten Aufnahmen als signalreiche Strukturveränderungen. Aufgrund der hohen anatomischen Detailerkennbarkeit eignet sich die hochauflbsende Kernspintomographie als ergänzendes diagnostisches Verfahren zur nichtinvasiven Diagnostik von traumatischen Knorpel- und Bandläsionen. Unter Berücksichtigung des Zeitaufwandes handelt es sich dabei um eine im klinischen Alltag praktikable Methode.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Magnetic resonance materials in physics, biology and medicine 4 (1996), S. 19-25 
    ISSN: 1352-8661
    Keywords: magnetic resonance imaging ; cardiac activation sequence ; Fourier phase analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics
    Notes: Abstract To establish cardiac MRI as a tool for noninvasive evaluation of activation patterns, 10 healthy volunteers were examined by cine segmented turboFLASH imaging sequences. Sequence modifications for low signal blood-pool appearance were applied, i.e., bilateral spatial saturation for segmented turboFLASH imaging. Pixelwise calculation of first-harmonic Fourier phase values (displayed as color-encoded maps) reveal either anterior septal or left ventricular free-wall sites as areas of earliest phase spreading towards posterior paraseptal sites in segmented turboFLASH scans. Phase scatter is lower in unsaturated than spatially presaturated segmented turboFLASH studies. Phase standard deviation in areas of endocardial displacement is higher in basal than apical slice positions in these scans. Early results indicate that first-harmonic Fourier phase analysis of cardiac-segmented turboFLASH MRI cine studies may provide a tool for noninvasive studies of cardiac activation sequence.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1352-8661
    Keywords: magnetic resonance imaging ; surface coils ; MR-imaging technology ; tissue characterization ; skin ; wrist ; finger ; Achilles tendon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics
    Notes: Abstract To investigate the application of a mini-coil surface system for high-resolution MRI, 60 volunteers were examined in a 1.5-T whole-body scanner. Two replaceable probe heads were available: a circular 2.5-cm coil and a quadratic 5-cm coil, both of which were placed directly on the skin. The skin layers, Achilles tendon and finger joints were examined with the 2.5-cm coil and a FOV of 25 × 25 mm2. A matrix of 256 × 256 pixels resulted in a pixel size of 0.098 × 0.098 mm2. For imaging of the carpal tunnel, the 5-cm coil was used in transverse orientation. The FOV was 50 × 50 mm2 so that a matrix of 256 × 256 pixels led to a pixel size of 0.195 × 0.195 mm2. The resulting spatial resolution permitted visualization of the epidermis, dermis and subcutis, resulting in clear definition of anatomical detail of the musculoskeletal system. MRI measurement of skin-layer thickness did not correlate with histometric data (p〈0.05). This discrepancy was due in part to shrinkage of the tumor specimen on histologic preparation. Other causes include the motion artifacts and the limited accuracy of determining thickness on the MRI display unit.
    Type of Medium: Electronic Resource
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