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ZusammenfassungZiel: Es sollte überprüft werden, inwieweit die noch neue Technik des B-Flow eine verbesserte sonographische Flusserfassung bei stenosierten Hämodialyseshunts ermöglicht. Material und Methode: Bei 50 Patienten (im Mittel 58 Jahre) mit Brescia-Cimino-Shunts (27 radiale, 23 cubitale A-V-Fisteln) wurden prospektiv Untersuchungen mit der i. a. DSA und dem Gefäßultra-schall durchgeführt. Voraussetzung für die Untersuchungen waren ein Flussvolumen < 400 ml/min, eine vermutete hämodyna-misch relevante Stenose im Bereich der Anastomose oder der Shuntvenen. Die Ultraschalluntersuchungen erfolgten mit einem Multifrequenzschallkopf Purpose: To evaluate the new technique of B-flow ultrasound in assessing stenoses of hemodialysis fistulas. Materials and Methods: 50 patients (mean age 58 years) with Brescia-CiminoShunts (27 shunts of the radial and 23 of the cubital artery) were prospectively assessed with intraarterial DSA and vascular ultrasound by independent examiners. Eligibility for the study was a shunt-volume of less than 400 ml/min and an angiographically suspected hemodynamically significant stenosis of the anastomosis or of shunt veins. Sonography was performed with a multifrequency ultrasound probe (5 to 10 MHz, Logic 700, GE) using B-mode, color coded Doppler sonography (CCDS) and B-flow technique. Results: Anastomotic stenosis and stenosis of the shunt veins were equally distributed, found in 25 patients each. The measurements of the residual lumen of the 25 anastomotic stenoses were 1.47 to 3.43 mm (average: 2.3 mm) for intraarterial DSA, 1.57 to 3.73 mm (average: 2.6 mm) for B-mode ultrasound, 1.97 to 4.17 mm (average: 2.9 mm) for CCDS, 1.43 to 3.47 mm (average: 2.3 mm) for B-flow technique in the brightness mode and 1.6 to 3.47 mm (average: 2.4 mm) for B-flow technique in the B-mode. The brightness mode of the B-flow correlated best with intraarterial DSA (r=0.994), with a significantly lower correlation between CCDS and intraarterial DSA. B-flow displays less vascular distortion within the stenosis and fewer flow artifacts. Even in angulated stenoses, the detected intra-and poststenotic flow was markedly less angle-dependent in comparison with CCDS. B-flow clearly facilitates the visualization of hypoechoic plaques and intima proliferation. Furthermore, excentric cicatricial stenoses, intima flaps or hypoechoic thrombi, which were not seen with DSA or B-mode, showed improved visualization in