A Comparison of the Diagnostic Accuracy and Reliability of Subjective Grading and Computer-Aided Assessment of Intranodal Vascularity in Differentiating Metastatic and Reactive Cervical Lymphadenopathy

Abstract

Purpose: Ultrasound is a well-established imaging modality in the assessment of malignant cervical lymphadenopathy. With the use of Doppler ultrasound, intranodal vascularity can be evaluated. However, the major limitation of ultrasound is operator dependency. Therefore, this study aimed to evaluate and compare the diagnostic accuracy and reliability of the subjective grading and computer-aided approach in assessing intranodal vascularity for the differentiation of benign and malignant lymph nodes.

Materials and Methods: The present study retrospectively assessed 99 power Doppler ultrasound images of cervical lymph nodes and evaluated the degree of intranodal vascularity using qualitative subjective grading (QSG) and quantitative computer-aided (QCA) methods. The diagnostic accuracy of the two methods in distinguishing metastatic and reactive nodes and their inter- and intra-rater reliability in assessing intranodal vascularity were evaluated and compared.

Results: The results showed that the QCA method was more accurate than the QSG method with a significantly higher sensitivity (67.8 % and 61.9 %, respectively, p < 0.05) and specificity (73.3 % and 57.3 %, respectively, p < 0.05). Using the intranodal vascularity index as determined by the QCA approach, the optimum cut-off to differentiate metastatic and reactive cervical lymph nodes was 32 %. The QCA method showed higher inter- and intra-rater reliability than the QSG method.

Conclusion: In the assessment of the degree of intranodal vascularity, the QCA method was more accurate and reliable than the QSG method in distinguishing metastatic and reactive lymph nodes.

Zusammenfassung

Ziel: Die Sonografie gilt als bewährtes bildgebendes Verfahren bei der Beurteilung der malignen zervikalen Lymphadenopathie. Die intranodale Vaskularität kann mittels Doppler-Ultraschall ausgewertet werden. Allerdings ist die größte Einschränkung der Sonografie deren Bedienerabhängigkeit. Daher ist das Ziel dieser Studie, die diagnostische Genauigkeit und Zuverlässigkeit in Bezug auf die subjektive Einstufung und den computergestützten Ansatz bei der Beurteilung der intranodaler Vaskularität bei der Differenzierung von benignen und malignen Lymphknoten zu bewerten und zu vergleichen.

Material und Methoden: Die vorliegende Studie beurteilt retrospektiv 99 Power-Doppler-Ultraschallbilder zervikaler Lymphknoten und bewertet den Grad der intranodalen Vaskularität mittels qualitativer subjektiver Einstufung (QSG) und mittels quantitativer computergestützter (QCA)-Methoden. Die diagnostische Genauigkeit beider Verfahren in Bezug auf die Unterscheidung zwischen metastasierenden und reaktiven Knoten sowie deren Inter- und Intrarater-Reliabilität bei der Beurteilung der intranodalen Vaskularität wurden ausgewertet und verglichen.

Ergebnisse: Die Ergebnisse zeigten, dass die QCA-Methode genauer als das QSG-Verfahren war, mit einer signifikant höheren Sensitivität (QCA 67,8 %; QSG 61,9 %, p < 0,05) und Spezifität (QCA 73,3 %, QSG 57,3 %, p < 0,05). Mit dem im QCA-Ansatz bestimmten intranodalen Vaskularitätsindex betrug der optimale Grenzwert für die Differenzierung von metastasierenden und reaktiven Lymphknoten 32 %. Die QCA-Methode zeigte eine höhere Inter- und Intrarater-Reliabilität im Vergleich zur QSG-Methode.

Schlussfolgerung: Bei der Beurteilung des Grades der intranodalen Vaskularität zur Unterscheidung metastasierender und reaktiver Lymphknoten war das QCA-Verfahren genauer und zuverlässiger als die OSG-Methode.

Key words

head/neck - ultrasound-power Doppler - metastases - lymph nodes

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