title: [Improved evaluation of stenoses of hemodialysis fistulas by B-flow ultrasound].
abstract: OBJECTIVE
  To evaluate the new technique of B-flow ultrasound in assessing stenoses of hemodialysis fistulas.
  
  
  METHODS
  50 patients (mean age 58 years) with Brescia-Cimino-Shunts (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, eccentric cicatricial stenoses, intima flaps or hypoechoic thrombi, which were not seen with DSA or B-mode, showed improved visualization in comparison with CCDS.
  
  
  CONCLUSIONS
  Ultrasound B-flow makes it easier to assess the morphology and the local degree of stenotic hemodialysis fistulas. Flow detection is achieved with fewer artifacts and reduced angle dependence. This opens the way for better planning of interventional therapy.
authors.affiliation: Institut für Röntgendiagnostik, Klinikum Passau. jung@fmi.uni-passau.de
authors.forename: E M
authors.initials: EM
authors.lastname: Jung
authors.forename: R
authors.initials: R
authors.lastname: Kubale
authors.forename: D-A
authors.initials: DA
authors.lastname: Clevert
authors.forename: N
authors.initials: N
authors.lastname: Rupp
mesh_terms: D000368:Aged; D000783:Aneurysm / Q000000981:diagnostic imaging / Q000209:etiology; D015901:Angiography, Digital Subtraction; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D016477:Artifacts; D003251:Constriction, Pathologic; D003627:Data Interpretation, Statistical; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000295:instrumentation*; D018615:Ultrasonography, Doppler, Color; D018084:Ultrasonography, Interventional; D014654:Vascular Patency