Renal artery doppler ultrasound6/23/2023 ![]() Die Studienlage für die Graduierung von In-Stent-Rezidivstenosen ist kontrovers, tendenziell höhere Cut-off-Werte für PSV und RAR sind jedoch anzunehmen. Stenosen bei fibromuskulären Dysplasien können sonographisch nach dem Kontinuitätsgesetz zuverlässig graduiert werden. Früher wurden erst höhergradige Stenosen als therapierelevant angesehen, andererseits wird inzwischen schon der Druckabfall von > 20 mmHg bei > 50%igen Stenosen (PSV 180 cm/s) als relevant für einen Reninanstieg bewertet. Die Kontrastmittelsonographie (CEUS) verbessert durch die Echokontrastverstärkung die Treffsicherheit. Andere Methoden wie der Quotient aus PSV in Aorta und Nierenarterie (RAR) oder indirekte Kriterien wie der Widerstandsindex im Seitenvergleich (dRI) oder die Akzelerationszeit können ergänzend zu Verbesserung der Treffsicherheit herangezogen werden. Die meisten Studien ermitteln in ROC-Kurven bei einer PSV > 180–200 cm/s Sensitivitäten und Spezifitäten von 85–90 % für > 50%igen Stenosen. ![]() Whilst MRA and CTA demonstrate an accuracy of > 90 %, this is at the cost of possible side effects for patients, particularly in the case of pre-existing renal parenchymal damage.ĭie PSV bietet als direkte Messmethode in der Stenosendetektion und Graduierung die höchste Sensitivität und Spezifität. Although the available studies on the grading of in-stent restenosis are the subject of controversy, there is a tendency to assume higher cut-off values for PSV and RAR. Stenosis in fibromuscular dysplasia can be reliably graded according to the continuity equation. Although in the past only high-grade stenosis was considered relevant for treatment, a drop in pressure of > 20 mmHg in > 50 % stenosis (PSV 180 cm/s) is classified as relevant for increased renin secretion. Contrast-enhanced ultrasound improves accuracy by means of echo contrast enhancement. Other methods, such as the ratio of the PSV in the aorta to the PSV in the renal artery (RAR) or indirect criteria, such as side to side differences in RI (dRI) or AT can be additionally used to improve accuracy. Most studies found sensitivities and specificities of 85–90 % for > 50 % stenosis at a PSV > 180–200 cm/s in ROC curve analysis. Occurs within 1.5-2.The PSV provides high sensitivity and specificity as a direct measurement method in stenosis detection and grading. Termed aberrant renal arteries when they enter renal capsule in the upper or lower pole rather than the hilumĮarly-branching (or prehilar branching): occurs in ~10% of the population May arise from the aorta below (more commonly) or above the renal artery common occur in ~30% of the population, bilateral in ~10% Normal renal arterial resistive index (RI) is ≈ 0.60 Normal peak systolic velocity is 150-180 cm/s and elevation beyond this may indicate renal artery stenosis of >60% 4 The afferent arterioles, which supply the glomeruli, originate from the interlobular arteries.Ĭan be technically difficult and only completed in 60% of patients These then divide into lobar branches which successively branch into interlobar, arcuate, and interlobular arteries. The dorsal and ventral rami divide into segmental branches within the renal hilum before entering the parenchyma: apical, anterior superior, anterior inferior (middle), inferior and posterior segmental renal arteries. ![]() These branches are very small and often not visible on imaging studies: BranchesĮach renal artery gives off small branches in its proximal course, prior to dividing into dorsal and ventral rami. Renal arteries are between 4-6 cm in length and usually 5-6 mm in diameter. ![]() The left renal artery courses more horizontally, posterior to the left renal vein to enter the renal hilum. The left renal artery is much shorter and arises slightly more superior to the right main renal artery. The right renal artery courses inferior and obliquely, passing posterior to the IVC and the right renal vein to reach the renal hilum. They arise from the lateral surface of the abdominal aorta at the L1-2 vertebral body level, inferior to the origin of the superior mesenteric artery. ![]()
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