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  • 1
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Spiral-CT ; Virtuelle Endoskopie ; Larynx ; Key words Helical CT ; Virtual endoscopy ; Larynx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary This pilot study investigated the feasibility and clinical value of high-resolution virtual real-time laryngoscopy based on helical CT data sets. Nine patients with laryngeal pathology (three with tumors of the vocal cords, two laryngeal carcinomas, one with invasion of the larynx by thyroid carcinoma and six subglottic stenoses) underwent examination by helical CT at a collimation of 1 mm. Following acquisition, the images were processed at a workstation with standard visualization software, such that virtual endoscopy (VE) in real time was possible. The images were then compared with the findings of conventional endoscopy. Because of swallowing artifacts, reconstruction failed in 2 of 12 patients. None of the carcinomas of the vocal cords was recognized at VE or in the cross-sectional CT images. VE provided the correct diagnosis in 8 of 12 cases (laryngeal tumors, subglottic stenoses). Virtual laryngoscopy is capable of simulating the visual findings of endoscopy in cases of laryngeal tumors and subglottic stenoses. Small tumors of the vocal cords are not adequately visualized. The major problem affecting results is motion artifacts resulting from involuntary swallowing.
    Notes: Zusammenfassung Im vorliegenden Beitrag wird eine Pilotstudie zur Überprüfung der Machbarkeit und des klinischen Nutzens einer hochauflösenden virtuellen Echtzeitlaryngoskopie aus Spiral-CT-Datensätzen vorgestellt. 12 Patienten mit Erkrankungen im Kehlkopfbereich (3 Stimmlippentumore, 2 Larynxkarzinome, ein in den Larynx eingebrochenes Schilddrüsenkarzinom und 6 subglottische Stenosen) wurden mittels hochauflösender Spiral-CT (Kollimation 1 mm) untersucht. Anschließend wurden die Bilder auf einer Workstation mit einer standardmäßigen Visualisierungssoftware so rekonstruiert, daß eine virtuelle Endoskopie (VE) in Echtzeit möglich wurde, welche der herkömmlichen Fiberendoskopie gegenübergestellt wurde. 2 der 12 Patienten waren bedingt durch Schluckartefakte nicht zu rekonstruieren. Keines der Stimmlippenkarzinome war in der VE oder den Querschnittsbildern zu erkennen. In 8 von 12 Fällen war die VE diagnostisch (Larynxtumore, subglottische Stenosen). Die virtuelle Laryngoskopie in der hier beschriebenen Technik vermag Larynxtumoren und subglottische Stenosen, nicht aber kleine Stimmbandtumoren in einer dem Kliniker vertrauten endoskopischen Sichtweise darzustellen. Hauptproblem sind Bewegungsartefakte durch unwillkürliche Schluckbewegungen.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1084
    Keywords: Key words: Breast ; Parenchymal pattern ; MR imaging ; Contrast enhancement ; MR mammography ; Menstruation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Magnetic resonance mammography (MRM) provides data regarding the nature of tumours based on contrast medium dynamics; fibrocystic changes in the breast, however, may lead to false-positive results. This study investigated whether the contrast medium dynamics of fibrocystic changes are dependent on the menstrual cycle. Twenty-four patients with palpable lumps but normal mammographies and ultrasound studies were examined. The MRM technique was performed during the first and second part of the menstrual cycle using a FLASH 3D sequence, both native and at 1, 2, 3 and 8 min after intravenous application of 0.15 mmol/kg body weight of gadodiamide. The calculated time–intensity curves were evaluated based on the following criteria: early percentage of contrast medium uptake in relation to the native value; formation of a plateau phenomenon after the second minute; the point of maximal contrast medium uptake; and calculation of the contrast enhancing index. During the second half of the menstrual cycle, a generally greater contrast medium uptake was observed. Nevertheless, when further diagnostic criteria, such as continuous contrast medium increase as a function of time, were considered, there was no increased rate of false-positive findings. The phase of the menstrual cycle may affect the specificity of the examination, if only the quantitative contrast medium uptake and the percentage of contrast medium uptake in the first 2 min are considered. A control MRM during the other half of the cycle may then be indicated and additional diagnostic criteria may improve specificity.
    Type of Medium: Electronic Resource
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