Comparison of Double Contrast-Enhanced Ultrasound and MDCT for Assessing Vascular Involvement of Pancreatic Adenocarcinoma: Preliminary Results Correlated with Surgical Findings

Abstract

Purpose: To investigate the accuracy of double contrast-enhanced ultrasound (DCEUS) for assessing vascular involvement by pancreatic adenocarcinoma.

Materials and Methods: 38 patients with pancreatic adenocarcinoma proven by postoperative pathology or biopsy were enrolled in this study. DCEUS (intravenous microbubbles combined with an oral contrast agent) and 16-row multi-detector CT (MDCT) were performed preoperatively to assess vascular invasion by pancreatic adenocarcinoma. The diagnostic accuracy of DCEUS and MDCT for assessing vascular involvement was calculated and compared. ROC curves were used to evaluate the diagnostic confidences of the two methods. The inter- and intra-observer reliability of DCEUS for assessing vascular invasion was investigated in the present study.

Results: Almost perfect agreement between DCEUS and MDCT was obtained using Kappa analysis (k = 0.83, p = 0.000). Compared with surgical findings, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of peripancreatic vascular invasion were 66.67 %, 100 %, 100 %, 60 %, and 77.78 %, respectively, for DCEUS and 75 %, 100 %, 100 %, 66.67 %, and 83.33 %, respectively, for MDCT. There was no significant difference in accuracy between DCEUS and MDCT for evaluating peripancreatic vascular invasion (p = 0.108). The combination of DCEUS and MDCT increased the diagnostic confidence in assessing peripancreatic vascular invasion with an area under ROC curve from 0.83 for DCEUS (p = 0.025) and 0.88 for MDCT (p = 0.011) to 0.92 for both combined (p = 0.005). The intra- and inter-observer reproducibility were both almost perfect for assessing the peripancreatic vascular invasion by DCEUS with a Kappa value of 0.94 (p = 0.000) for intra-observer and 0.83 (p = 0.000) for inter-observer.

Conclusion: DCEUS could be considered as a reliable and accurate method for evaluating the peripancreatic vascular invasion of pancreatic adenocarcinoma.

Zusammenfassung

Ziel: Die Untersuchung der Genauigkeit des doppelt kontrastverstärkten Ultraschalls (DCEUS) zur der Bewertung der Gefäßbeteiligung beim duktalen Adenokarzinom des Pankreas.

Material und Methoden: 38 Patienten mit einem durch postoperative Pathologie oder Biopsie diagnostizierten Adenokarzinom des Pankreas wurden in die Studie aufgenommen. DCEUS (intravenöse Mikrobläschen in Kombination mit einem oralen Kontrastmittel) und eine 16-Zeilen-Multidetektor-Computertomografie (MDCT) wurden präoperativ durchgeführt, um die Gefäßinvasion bei Pankreaskarzinomen zu bewerten. Die diagnostische Genauigkeit von DCEUS und MDCT zur Bewertung der Gefäßbeteiligung wurde berechnet und miteinander verglichen. ROC-Kurven wurden eingesetzt, um die diagnostische Güte der beiden Methoden zu bewerten. Die Inter- und Intraobserver-Reliabilität von DCEUS bei der Bewertung der Gefäßinvasion wurde in der vorliegenden Studie untersucht.

Ergebnisse: Ein ausgezeichnete Übereinstimmung zwischen DCEUS und MDCT wurde bei der Kappa-Analyse erzielt (k = 0,83; p = 0,000). Im Vergleich zu den chirurgischen Befunden betrug die Sensitivität von DCEUS bei der Bewertung der peripankreatischen Invasion 66,67 %, die Spezifität 100 %, der positive Vorhersagewert (PVW) 100 % und negative Vorhersagewert (NVW) 60 %. Bei der MDCT betrug die Sensitivität 75 %, die Spezifität 100 %, der PVW 66,67 % und der NVW 83,33 %. Bei der Bewertung der peripankreatischen Invasion gab es keinen signifikanter Unterschied der Genauigkeiten von DCEUS und MDCT (p = 0,108). Die Kombination von DCEUS und MDCT zur Bestimmung der peripankreatischen Invasion führte zu einer höheren diagnostischen Güte mit einer Fläche unter der ROC-Kurve von 0,83 für DCEUS (p = 0,025) und 0,88 für MDCT (p = 0,011) alleine und 0,92 für beide in Kombination (p = 0,005). Sowohl die Intra- als auch die Interobserver-Reproduzierbarkeit für DCEUS bei der Bewertung der peripankreatischen Gefäßinvasion waren nahezu perfekt mit einem Kappa-Wert von 0,94 (p = 0,000) für die Intraobserver- und von 0,83 (p = 0,000) für die Interobserver-Reproduzierbarkeit.

Schlussfolgerung: DCEUS kann als verlässliche und genaue Methode zur Bewertung der peripankreatischen Gefäßinvasion bei Adenokarzinomen des Pankreas in Betracht gezogen werden.

Key words

abdomen - contrast agents - ultrasound

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