Zusammenfassung
Ziel: Ultraschall-Elastographie ist ein neues bildgebendes Verfahren, welches die Rekonstruktion der Elastizitätsverteilung erlaubt, indem es den Unterschied in der Festigkeit von krankhaftem und normalem Gewebe nachweist. Material und Methoden: Ziel unserer Untersuchung war die Anwendung der Echtzeit-Elastographie während endoskopischer Ultraschalluntersuchungen (EUS), um hierdurch den Unterschied zwischen benignen und malignen Lymphknoten herauszuarbeiten. Das Muster der Echtzeit-EUS-Elastographiebilder wurde mit dem Aussehen der Lymphknoten beim konventionellen EUS sowie mit der endgültigen zytologischen Diagnose durch EUS-Feinnadelbiopsie (FNB) und/oder dem Pathologie-Ergebnis nach chirurgischer Resektion verglichen. Ergebnisse: Patienten, bei den durch EUS zervikale, mediastinale oder abdominelle Lymphknotenveränderungen festgestellt worden waren, wurden in die prospektive Studie aufgenommen und insgesamt 42 Lymphknoten wurden mittels EUS elastographisch untersucht. Mithilfe einer qualitativen Musteranalyse konnten wir zwischen benignen und malignen Lymphknoten mit großer Sensitivität, Spezifität und Genauigkeit (jeweils 91,7 %, 94,.4 % und 92,86 %) unterscheiden. Grundlage stellten fünf vorher ermittelte Muster dar, die auf EUS-elastographischen Untersuchungen beruhten. Eine quantitative Analyse, die sich auf Histogramme der EUS-Elastographiebilder stützte, erlaubte ebenfalls eine ausgezeichnete Unterscheidung zwischen benignen und malignen Lymphknoten. Gestützt auf separate RGB-Kanal-Histogrammwerte wurde zusätzlich ein „Elastizitätsverhältnis” definiert, welches in Bezug auf die Differenzialdiagnose eine Sensitivität, Spezifität und Genauigkeit von jeweils 95,8 %, 94,4 % und 95,2 % ergab, ausgehend von einem Cut-off-Wert von 0,84. Schlussfolgerung: EUS-Elastographie ist eine viel versprechende Methode, die die Charakterisierung und Differenzierung von benignen und malignen Lymphknoten mit einer hohen Sensitivität, Spezifität und Genauigkeit erlaubt und damit zusätzliche Information zur konventionellen EUS-Untersuchung bietet.
Abstract
Purpose: Ultrasound elastography is a new imaging procedure which allows the reconstruction of elasticity distribution by characterising the difference of hardness between pathological and normal tissue. Materials and Methods: The aim of our study was to apply real-time elastography during endoscopic ultrasound (EUS) examinations and to consequently characterise benign versus malignant lymph nodes. The pattern of real-time EUS elastography images was compared with the conventional EUS aspects of lymph nodes and with the final diagnosis obtained by EUS-FNA cytology analysis and/or by surgical pathology. Results: Patients diagnosed by EUS with cervical, mediastinal or abdominal lymph nodes were prospectively included, with a total number of 42 lymph nodes examined by EUS elastography. By using a qualitative pattern analysis, we were able to differentiate between benign and malignant lymph nodes with a high sensitivity, specificity and accuracy (91.7 %, 94.4 % and 92.86 %, respectively), based on five pre-defined patterns obtained on EUS elastography. A quantitative analysis based on histograms of the EUS elastography images also allowed an excellent discrimination between benign and malignant lymph nodes. Based on separate RGB channel histogram values, an “elasticity ratio” was further defined and yielded a sensitivity, specificity and accuracy for the differential diagnosis of 95.8 %, 94.4 % and 95.2 % respectively, based on a cut-off level of 0.84. Conclusion: EUS elastography is a promising method which allows characterisation and differentiation of benign and malignant lymph nodes with a high sensitivity, specificity and accuracy, offering complementary information added to conventional EUS imaging.
Key words
elastography - endoscopic ultrasound - lymph nodes
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Adrian Săftoiu, M.D., Ph. D.
Department of Gastroenterology, University of Medicine and Pharmacy Craiova, Romania
Str. Horia nr. 11
Craiova, Dolj, 200490
Romania
Phone: ++4/07 44/82 33 55
Fax: ++4/02 51/53 45 96
Email: adry@umfcv.ro; adriansaftoiu@netscape.net