Increasing sensitivity and specificity of Doppler sonographic detection of renal transplant rejection with serial investigation technique

Abstract

Acute rejection episodes are the most common cause leading to loss of renal grafts in the early postoperative phase. Doppler sonography presents a noninvasive tool to detect increased arterial blood flow resistance as a result of rejection. This can be measured by the increase in the resistive index (RI) and the pulsatility index (PI). In a prospective study including 65 consecutive patients we investigated whether the detection of rejection episodes is improved by determining RI or PI serially twice a week instead of performing a single examination in cases of transplant dysfunction. In 330 examinations with a color-coded Doppler device (Philips QAD 1, Philips Medical Systems Hamburg, Germany) flow profiles were obtained by means of pulse-wave Doppler over at least three interlobar arteries of the renal transplant and RI and PI were calculated. In 41 cases primary rejections were better recognized by an increase in PI compared to the preceding value than by the absolute PI value (with a sensitivity of 90%; specificity was 76% and 42% respectively). The RI was less specific (with a sensitivity of 90%; specificity was 47% for the relative RI increase and 30% for the absolute RI value). The continuous PI increase started an average of 3.3 days (95% CI-15.25 to + 1.55) before rejection was diagnosed. Vascular rejection episodes showed higher PI values than interstitial rejections (3.86 +/- 2.14 vs. 2.19 +/- 0.87; P < 0.01). The serial investigation technique of PI allows better recognition of rejection episodes than the single measurement of RI or PI performed so far. Doppler sonography recognizes rejection at an early stage.

Evaluation of renal allograft function early after transplantation with diffusion-weighted MR imaging

“…Ultrasound characteristics of rejection occur only late after rejection and are nonspecific [16]. The addition of serial measurements of resistance index by colour-coded duplex ultrasound increases the sensitivity, but specificity remains low [17,18]. The diagnostic value of renal scintigraphy, especially for prediction of acute rejection, is also limited [19].…”

Pathomechanisms and the diagnosis of arterial hypertension in pediatric renal allograft recipients

“…To date, no reliable factor has been identified that predicts long-term allograft survival. Doppler sonography is a non-invasive tool for detecting increased arterial blood flow resistance as a result of acute and chronic rejection [55]. Recently, Radermacher et al [54] investigated in a cohort of 601 patients at least 3 months after transplantation whether the renal segmental arterial resistance index (described as a percentage reduction of the end-diastolic flow compared with the systolic flow) might be a predictor of renal allograft survival.…”

Die Transplantatniere: Farbkodierte Duplex-Sonographie und kontrastmittelverstärkte Sonographie in der Beurteilung nephrologischer und chirurgischer Komplikationen

“…Auch die FKDS oder die Powerdoppler-(PD-)Sonographie können die Diagnose im Einzelfall nicht sicherstellen [22,23]. Eine engmaschige sonographische Verlaufskontrolle in der Frühphase nach NTX ist hingegen hilfreich, um sich gemeinsam mit Klinik und Paraklinik der Diagnose einer akuten Organabstoßung zu nähern und die Indikation zur Biopsie zu stellen [24]. Die Spezifität der FKDS zur Diagnosestellung der Rejektion wurde mit 25 [25] bis 90 % [26] ebenso wie die angegebene Sensitivität mit 35 [27] bis 94 % [28] sehr verschieden bewertet.…”

“…In der Praxis hat sich dabei die Bestimmung des nicht perfundierten subkapsulären SauTab. 3 Berechnungsgrundlagen des RI und PI[16,24,28] Abb. 4 Darstellung einer 22 mm großen echofreien zystischen Läsion nach Nierenbiopsie A. Im Breitbanddoppler (ADF) zeigt sich eine AVFistel B, welche sich ohne Therapie spontan zurückbildete.…”