B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation

Abstract

Objective To compare B-flow sonography (BFS) with color Doppler sonography (CDS) for imaging of kidney transplant vascularization in children.

Patients and Methods All children receiving a kidney transplantation who underwent a protocol-based ultrasound examination (Loqiq 9, GE Medical Systems, Milwaukee, WI, USA) using the BFS and CDS technique with equal settings and probe position between January 2013 and January 2016 were retrospectively assessed (n = 40). The obtained datasets were visually graded according to the following criteria: (I) delineation of the renal vascular tree (Grade 1 – clear demarcation of interlobar, together with arcuate and interlobular vessels; Grade 2 – clear demarcation of interlobar and cortical vessels, but no distinction of interlobular from arcuate vessels; Grade 3 – only clear demarcation of interlobar vessels, Grade 4 – insufficient demarcation) (II) delineation of cortical vessel density in ventral, lateral, and dorsal part of the transplant, (III) smallest vessel-capsule distance, and (IV) maximum cortical vessel count. Comparison between methods was performed using Fisher’s exact and paired sample t-tests.

Results Applying a curved transducer (C1–6), BFS showed superior delineation of the renal vascular tree (p < 0.001), a lower vessel-capsule distance (p < 0.001), a higher cortical vessel count (p < 0.001), and a higher cortical vessel density in the superficial cortex (p = 0.01) than CDS. In the dorsal and lateral aspects of the transplant, cortical vessel density was lower with BFS (both p < 0.001). Using a linear high-resolution transducer (ML 6–15), no significant differences between the methods were found.

Conclusion Improved imaging of kidney transplant vascularization can be achieved in children by adding BFS to a standard protocol. The BFS technique is especially beneficial for overall assessment of the renal vascular tree together with the extent of cortical vascularization on curved array images.

Key points: 

• Depiction of vascular tree and ventral cortical vessels is improved by BFS.

• The dorso-lateral cortex was better represented with CDS because of higher penetration.

• Additional monitoring with BFS improves the monitoring of transplant viability.

Citation Format

• Dammann E, Groth M, Schild R et al. B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation. Fortschr Röntgenstr 2021; 193: 49 – 60

Zusammenfassung

Ziel Die Beurteilung der Gefäßversorgung transplantierter Nieren im Kindesalter mittels B-Flow-Sonografie (BFS) im Vergleich zur Color-Doppler-Sonografie (CDS).

Patienten und Methoden Alle Kinder nach Nierentransplantation, die im Zeitraum von Januar 2013 bis Januar 2016 in unserer Klinik eine protokollbasierte Ultraschalluntersuchung in BFS- und CDS-Technik mit identischen Grundeinstellungen erhielten (Loqiq 9, GE Medical Systems, Milwaukee, WI, USA), wurden retrospektiv evaluiert (n = 40). Die erhaltenen Bilddaten wurden visuell klassifiziert: (I.) Darstellung des gesamten renalen Gefäßbaums (Grad 1 – interlobäre, arcuatae und interlobuläre Gefäße abgrenzbar; Grad 2 – interlobäre und kortikale Gefäße abgrenzbar, nicht arcuatae von interlobulären Gefäßen abgrenzbar; Grad 3 – nur interlobäre Gefäße abgrenzbar; Grad 4 – insuffiziente Abgrenzbarkeit), (II.) Dichte der Kortexgefäße im ventralen, lateralen und dorsalen Nierenanteil, (III.) geringster Gefäß-Kapsel-Abstand und (IV.) maximale Anzahl von Kortexgefäßen. Der statistische Vergleich erfolgte mittels exaktem Fisher-Test und gepaartem T-Test.

Ergebnisse Unter Verwendung eines Sektorschallkopfes (C1–6) zeigte BFS im Vergleich mit CDS eine vollständigere Darstellung des renalen Gefäßbaums (p < 0,001) mit einem geringeren Gefäß-Kapsel-Abstand (p < 0,001) und einer höheren maximalen Gefäßdichte im ventralen Kortex (p < 0,001) mit einer höheren max. Anzahl von Gefäßen (p = 0,01). Im dorsalen und lateralen Transplantatanteil war die nachweisbare Gefäßdichte niedriger mit BFS als mit CDS (jeweils p < 0,001). Unter Verwendung eines hochauflösenden Linearschallkopfes (ML 6–15) konnte kein Unterschied zwischen BFS und CDS nachgewiesen werden.

Schlussfolgerung Eine verbesserte Darstellung des Vaskularisationsgrades von Nierentransplantaten im Kindesalter kann erreicht werden, indem BFS zum Standardprotokoll hinzugefügt wird. Die BFS zeigt insbesondere Vorteile in der Erfassung des renalen Gefäßbaums und der Charakterisierung der schallkopfnahen Kortexgefäße unter Verwendung eines Konvexschallkopfes

Kernaussagen: 

• BFS verbessert die Darstellung des Gefäßbaums und der schallkopfnahen Kortexregion in Nierentransplantaten.

• Im dorsolateralen Kortex ist die Gefäßdarstellung mit CDS aufgrund besserer Penetration günstiger.

• Die Ergänzung eines Standardprotokolls mit BFS erlaubt ein qualitativ verbessertes Transplantatmonitoring.

Key words

ultrasonography - doppler - color - kidney transplantation - child

Publikationsverlauf

Eingereicht: 27. Juni 2019

Angenommen: 20. April 2020

Artikel online veröffentlicht:
09. Juni 2020

• References

• 1 Burgos FJ, Pascual J, Marcen R. et al The role of imaging techniques in renal transplantation. World J Urol 2004; 22: 399-404 . doi:10.1007/s00345-004-0412-1
• 2 Baxter GM. Imaging in renal transplantation. Ultrasound Q 2003; 19: 123-138
• 3 Sugi MD, Joshi G, Maddu KK. et al Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review. Radiographics 2019; 39: 1327-1355 . doi:10.1148/rg.2019190096
• 4 Irshad A, Ackerman SJ, Campbell AS. et al. An overview of renal transplantation: current practice and use of ultrasound. Semin Ultrasound CT MR 2009; 30: 298-314
• 5 Nixon JN, Biyyam DR, Stanescu L. et al Imaging of pediatric renal transplants and their complications: a pictorial review. Radiographics 2013; 33: 1227-1251 . doi:10.1148/rg.335125150
• 6 Grenier N, Douws C, Morel D. et al Detection of vascular complications in renal allografts with color Doppler flow imaging. Radiology 1991; 178: 217-223 . doi:10.1148/radiology.178.1.1984307
• 7 Taylor KJ, Morse SS, Rigsby CM. et al Vascular complications in renal allografts: detection with duplex Doppler US. Radiology 1987; 162: 31-38 . doi:10.1148/radiology.162.1.3538150
• 8 Platt JF, Rubin JM, Ellis JH. Acute renal obstruction: evaluation with intrarenal duplex Doppler and conventional US. Radiology 1993; 186: 685-688 . doi:10.1148/radiology.186.3.8430174
• 9 Barba J, Rioja J, Robles JE. et al Immediate renal Doppler ultrasonography findings (<24h) and its association with graft survival. World J Urol 2011; 29: 547-553 . doi:10.1007/s00345-011-0666-3
• 10 Weskott HP. B-flow – a new method for detecting blood flow. Ultraschall in Med 2000; 21: 59-65 . doi:10.1055/s-2000-319
• 11 Henri P, Tranquart F. B-flow ultrasonographic imaging of circulating blood. J Radiol 2000; 81: 465-467
• 12 Wachsberg RH. B-flow, a non-Doppler technology for flow mapping: early experience in the abdomen. Ultrasound Q 2003; 19: 114-122
• 13 Mikami T, Takahashi A, Houkin K. Evaluation of blood flow in carotid artery stenosis using B-flow sonography. Neurol Med Chir (Tokyo) 2003; 43: 528-532 ; discussion 533
• 14 Hancerliogullari KO, Soyer T, Tosun A. et al Is B-Flow USG superior to Color Doppler USG for evaluating blood flow patterns in ovarian torsion?. J Pediatr Surg 2015; 50: 1156-1161 . doi:10.1016/j.jpedsurg.2014.08.028
• 15 Wachsberg RH. B-flow imaging of the hepatic vasculature: correlation with color Doppler sonography. Am J Roentgenol 2007; 188: W522-W533 . doi:10.2214/Am J Roentgenol.06.1161
• 16 Russo E, Cerbone V, Sciano D. et al Posttransplant renal monitoring with B-flow ultrasonography. Transplant Proc 2010; 42: 1127-1129 . doi:10.1016/j.transproceed.2010.03.050
• 17 Hongmei W, Ying Z, Ailu C. et al Novel application of four-dimensional sonography with B-flow imaging and spatiotemporal image correlation in the assessment of fetal congenital heart defects. Echocardiography 2012; 29: 614-619 . doi:10.1111/j.1540-8175.2011.01639.x
• 18 Groth M, Dammann E, Arndt F. et al. Comparison of B-Mode with B-Flow Sonography for the Evaluation of Femoral Arteries in Infants. Rofo 2017; DOI: 10.1055/s-0043-112249.
• 19 Groth M, Ernst M, Deindl P. et al B-Flow Sonography for Evaluation of Basal Cerebral Arteries in Newborns. Clin Neuroradiol 2019; 29: 95-100 . doi:10.1007/s00062-017-0624-6
• 20 Trillaud H, Merville P, Tran Le Linh P. et al Color Doppler sonography in early renal transplantation follow-up: resistive index measurements versus power Doppler sonography. Am J Roentgenol 1998; 171: 1611-1615 . doi:10.2214/ajr.171.6.9843297
• 21 Martinoli C, Crespi G, Bertolotto M. et al Interlobular vasculature in renal transplants: a power Doppler US study with MR correlation. Radiology 1996; 200: 111-117 . doi:10.1148/radiology.200.1.8657897
• 22 Gruenewald S, Skerrett D, Dolimier D. et al. Technique of color Doppler quantification of vascularity in transplanted kidneys. J Clin Ultrasound 2002; 30: 151-157
• 23 Nankivell BJ, Chapman JR, Gruenewald SM. Detection of chronic allograft nephropathy by quantitative doppler imaging. Transplantation 2002; 74: 90-96
• 24 Schwenger V, Korosoglou G, Hinkel UP. et al Real-time contrast-enhanced sonography of renal transplant recipients predicts chronic allograft nephropathy. Am J Transplant 2006; 6: 609-615 . doi:10.1111/j.1600-6143.2005.01224.x
• 25 Radermacher J, Mengel M, Ellis S. et al The renal arterial resistance index and renal allograft survival. N Engl J Med 2003; 349: 115-124 . doi:10.1056/NEJMoa022602
• 26 Fischer T, Filimonow S, Dieckhofer J. et al Improved diagnosis of early kidney allograft dysfunction by ultrasound with echo enhancer--a new method for the diagnosis of renal perfusion. Nephrol Dial Transplant 2006; 21: 2921-2929 . doi:10.1093/ndt/gfl313
• 27 Heling KS, Chaoui R, Bollmann R. Advanced dynamic flow – a new method of vascular imaging in prenatal medicine. A pilot study of its applicability. Ultraschall in Med 2004; 25: 280-284 . doi:10.1055/s-2004-813383
• 28 Machado P, Segal S, Lyshchik A. et al A Novel Microvascular Flow Technique: Initial Results in Thyroids. Ultrasound Q 2016; 32: 67-74 . doi:10.1097/RUQ.0000000000000156
• 29 Sidhu PS, Cantisani V, Deganello A. et al Role of Contrast-Enhanced Ultrasound (CEUS) in Paediatric Practice: An EFSUMB Position Statement. Ultraschall in Med 2017; 38: 33-43 . doi:10.1055/s-0042-110394
• 30 Harvey CJ, Sidhu PS, Bachmann Nielsen M. Contrast-enhanced ultrasound in renal transplants: applications and future directions. Ultraschall in Med 2013; 34: 319-321 . doi:10.1055/s-0033-1350138
• 31 Sidhu PS, Cantisani V, Dietrich CF. et al The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version). Ultraschall in Med 2018; 39: e2-e44 . doi:10.1055/a-0586-1107
• 32 Morgan TA, Maturen KE, Dahiya N. et al US LI-RADS: ultrasound liver imaging reporting and data system for screening and surveillance of hepatocellular carcinoma. Abdom Radiol (NY) 2018; 43: 41-55 . doi:10.1007/s00261-017-1317-y