Contrast-Enhanced Endoscopic Ultrasound with Low Mechanical Index: A New Technique

Zusammenfassung

Einleitung: Im Unterschied zur transabdominellen Sonographie sind kontrastverstärkte Realtime-Techniken mit niedrigem mechanischen Index für die höherfrequente Endosonographie bisher nicht verfügbar gewesen. Wir berichten über die erstmalige Anwendung eines endosonographischen Prototypen zur kontrastverstärkten Realtime-Technik (CELMI-EUS). Patienten und Methoden: Elektronisches Echoendoskop Hitachi/Pentax EG-3830UT mit adaptierter dynamischer „contrast harmonic wideband pulsed inversion” Software mit niedrigem mechanischen Index (MI = 0,09 - 0,25) vor und nach Applikation von SonoVue® 4,8 ml bis zu 3 Minuten nach Injektion bei 6 konsekutiven Patienten zur Pankreas- und Leberpfortendarstellung. Ergebnisse: Die arteriellen und portalvenösen Gefäße sowie das Pankreas konnten bei allen Patienten adäquat kontrastiert werden. Das einsehbare Leberparenchym des linken Leberlappens zeigte eine ausreichende Kontrastierung bei 4 von 6 Patienten, wogegen bei 2 Patienten mit zirrhotischem Umbau die Leberparenchymkontrastierung unzureichend war. Diskussion: Erstmalig wird an einem Prototyp die kontrastverstärkte EUS-Technik mit niedrigem mechanischen Index beschrieben. Eine adäquate Kontrastierung arterieller und portalvenöser Gefäße sowie des Pankreas und gesunden Leberparenchyms ist möglich.

Abstract

Aim: Recent advances in technology have supported the development of new endoscopic ultrasound systems making it possible to use low MI contrast-enhanced imaging techniques (wide band harmonic imaging done with endoscopic ultrasound is currently at a preliminary stage). We now report on the first use of contrast-enhanced, low mechanical index, real-time endoscopic ultrasound (CELMI-EUS) in six patients using prototype technology. Materials and Methods: CELMI-EUS was performed using an electronic echo-endoscope HITACHI/Pentax EG-3830UT and adapted dynamic contrast harmonic wide-band pulsed inversion software with low mechanical index (MI = 0.09 - 0.25) before and up to 180 seconds after injection of SonoVue® (4.8 mL) in six patients. Results: Adequate visualisation of the arterial and portal venous phases was achieved in all patients. The pancreas and liver were studied thereafter. In contrast to the satisfactory visualisation of these vessels, enhancement of the left liver lobe was sufficient only in 4 patients. In the remaining 2 patients with liver cirrhosis, the enhancement was less pronounced in contrast to the strong enhancement of the hepatic artery and portal vein. Conclusion: Recent advances in technology have supported the development of new echo-endoscopic systems making it possible to use real-time, low mechanical index, contrast-enhanced imaging techniques with endoscopic ultrasound. We have preliminarily shown that arterial, portal venous and parenchymal contrast enhancement is possible.

Schlüsselwörter

Endosonographie - Ultraschallkontrastmittel - Sonovue® - Pankreas - Pfortaderthrombose

Key words

Endosonography - ultrasound contrast agent - Sonovue® - pancreas - portal vein thrombosis

References

• 1 Harvey C J, Blomley M J, Eckersley R J. et al . Pulse-inversion mode imaging of liver specific microbubbles: improved detection of subcentimetre metastases.  Lancet. 2000;  43 807-808
• 2 Blomley M, Albrecht T, Cosgrove D. et al . Stimulated acoustic emission imaging (”sono-scintigraphy”) with the ultrasound contrast agent Levovist: a reproducible Doppler ultrasound effect with potential clinical utility.  Acad Radiol. 1998;  43 S236-S239
• 3 Dietrich C F, Ignee A, Trojan J. et al . Improved characterisation of histologically proven liver tumours by contrast enhanced ultrasonography during the portal venous and specific late phase of SHU 508A.  Gut. 2004;  43 401-405
• 4 Dietrich C F. 3D real time contrast enhanced ultrasonography, a new technique.  Röfo Fortschr Geb Röntgenstr Neuen Bildgeb Verfahr. 2002;  43 160-163
• 5 Hocke M, Schulze E, Gottschalk P. et al . The use of contrast enhanced endoscopic ultrasound in discrimination between focal pancreatitis and pancreatic cancer.  World J Gastroenterol. 2005; in press; 
• 6 Rickes S, Unkrodt K, Ocran K. et al . Evaluation of Doppler ultrasonography criteria for the differential diagnosis of pancreatic tumors.  Ultraschall Med. 2000;  43 253-258
• 7 Rickes S, Unkrodt K, Neye H. et al . Differentiation of pancreatic tumours by conventional ultrasound, unenhanced and echo-enhanced power Doppler sonography.  Scand J Gastroenterol. 2002;  43 1313-1320
• 8 Ding H, Kudo M, Onda H. et al . Sonographic diagnosis of pancreatic islet cell tumor: value of intermittent harmonic imaging.  J Clin Ultrasound. 2001;  43 411-416
• 9 Kitano M, Kudo M, Maekawa K. et al . Dynamic imaging of pancreatic diseases by contrast enhanced coded phase inversion harmonic ultrasonography.  Gut. 2004;  43 854-859
• 10 Hirooka Y, Goto H, Ito A. et al . Contrast-enhanced endoscopic ultrasonography in pancreatic diseases: a preliminary study.  Am J Gastroenterol. 1998;  43 632-635
• 11 Becker D, Strobel D, Bernatik T. et al . Echo-enhanced color- and power-Doppler EUS for the discrimination between focal pancreatitis and pancreatic carcinoma.  Gastrointest Endosc. 2001;  43 784-789
• 12 Kasono K, Hyodo T, Suminaga Y. et al . Contrast-enhanced endoscopic ultrasonography improves the preoperative localization of insulinomas.  Endocr J. 2002;  43 517-522
• 13 Hyodo T, Hyodo N, Yamanaka T. et al . Contrast-enhanced intraductal ultrasonography for thickened bile duct wall.  J Gastroenterol. 2001;  43 557-559
• 14 Hyodo N, Hyodo T. Ultrasonographic evaluation in patients with autoimmune-related pancreatitis.  J Gastroenterol. 2003;  43 1155-1161
• 15 Hirooka Y, Naitoh Y, Goto H. et al . Contrast-enhanced endoscopic ultrasonography in gallbladder diseases.  Gastrointest Endosc. 1998;  43 406-410
• 16 Nomura N, Goto H, Niwa Y. et al . Usefulness of contrast-enhanced EUS in the diagnosis of upper GI tract diseases.  Gastrointest Endosc. 1999;  43 555-560
• 17 Sato T, Yamazaki K, Toyota J. et al . Evaluation of arterial blood flow in esophageal varices via endoscopic color Doppler ultrasonography with a galactose-based contrast agent.  J Gastroenterol. 2005;  43 64-69
• 18 Sato T, Yamazaki K, Toyota J. et al . Perforating veins in recurrent esophageal varices evaluated by endoscopic color Doppler ultrasonography with a galactose-based contrast agent.  J Gastroenterol. 2004;  43 422-428
• 19 Sato T, Yamazaki K, Toyota J. et al . Evaluation of hemodynamics in esophageal varices. Value of endoscopic color Doppler ultrasonography with a galactose-based contrast agent.  Hepatol Res. 2003;  43 55-61