Arrival time parametric imaging: a new ultrasound technique for quantifying perfusion of kidney grafts.

PURPOSE: Evaluation of a new standardised ultrasound (US) technique for diagnosis of acute rejection of kidney grafts. MATERIALS AND METHODS: Twenty-two kidney recipients underwent US examination following administration of 1.6 ml US contrast medium (USCM, SonoVue) 6 days after kidney transplantation. The examinations were performed with the Aplio US system (Toshiba). The difference in time to the first increase in signal intensity between the renal artery and the renal cortex was determined. Subsequently, the temporal course of contrast enhancement in the area of the renal artery following the first peak was recorded over 10 sec and depicted in colour using a Windows-based software. The resulting colour-time-images were evaluated by three readers who rated the images on an analogue scale from 1 (normal) to 5 (abnormal). RESULTS: 12 of the 22 patients had an uneventful clinical course. US demonstrated rapid inflow of the USCM into the renal cortex. The calculated time difference was 1.0 +/- 0.4 sec. The score assigned to the parametric images was 1.7 +/- 0.8. 8 of the 22 patients underwent biopsy and showed histologically proven rejection. The time difference in the rejection group was twice as high as in the normal group (2.2 +/- 0.7 sec, p < 0.05). The scores were in the abnormal range (3.7 +/- 1.6, p < 0.05). Two patients with perirenal haematoma also had high scores, without rejection. CONCLUSIONS: Acute rejection and perirenal haematoma are associated with a delayed signal increase in the renal cortex. This information can be provided with a single image with standardised colour display of the temporal course of USCM inflow.

Fast-track surgery in laparoscopic radical prostatectomy: basic principles.

Fast-track surgery describes innovative treatment concepts ensuring a faster convalescence phase. The aim of this study was to allow hospital discharge 3 days after surgery without additional complications in patients receiving LRPE for localized prostate cancer. Twenty-five patients each were randomized in the study groups to verify if a fast-track regimen could be transferred into clinical routine. The perioperative data, early complications, hospital stay as well as readmission rate were analyzed. The mean postoperative stay was 3.6 days in the fast-track group versus 6.7 days in the conventional group. The overall complications were significantly less in the fast-track procedure. The readmission rate was low and not significant. Patients receiving an LRPE benefit from a suitable fast-track concept. The postoperative hospital stay could be shortened nearly by half with a significantly decreased overall complication rate. Thus, fast-track concepts might contribute to saving resources in the long term. However, more evidence based on larger prospective trials is needed to achieve optimal quality of life for patients perioperatively.

[A new method for standardized diagnosis following renal transplantation. Ultrasound with contrast enhancement]. / Eine neue Methode zur standardisierten Diagnostik nach Nierentransplantation. Die ultraschallkontrastmittelgestützte Sonografie.

Ultrasound (US) imaging is an important diagnostic tool following renal transplantation. Unfortunately, due to the heterogeneity of the recipients and their multimorbidity, imaging procedures in the early phase after kidney transplantation are difficult and of limited use. We performed a study to evaluate the use of a contrast enhancer for US examination as a standardized method in the follow-up of kidney transplant recipients.The study included 40 recipients: 32 were examined on the 5th to 7th day following transplantation and 8 patients at the time when clinically suspicious findings occurred (acute rejection, tumor, acute tubular necrosis). Following the intravenous application of the contrast medium, pictures were taken during the arterial and parenchymatous phase and compared with conventional B-mode and power Doppler pictures of the same visual plane. Three examiners assessed different parameters of the transplant organ (max. vascularized area, suspected hematomas, tumors, rejection, acute tubular necrosis). Findings were confirmed by histological results of a biopsy if rejection, tumor, or acute tubular necrosis were suspected. Application of ultrasound contrast medium significantly increased visualization of the vascularized kidney area. Also, US findings in the follow-up after acute rejection therapy corresponded with the clinical course; 19 hematomas could be detected with contrast medium compared to only 9 without. With contrast medium a perfusion deficit was detectable in three patients compared to one patient with power Doppler US. Also, US contrast medium helped to detect tumor vascularization in two patients in whom conventional sonography suspected no abnormality. Ultrasound contrast medium enhancement is a reproducible, reliable, and easy to apply method which is superior to conventional sonography in the follow-up after kidney transplantation. This method is also helpful to detect and control acute rejections and to better visualize hematomas, deficits of perfusion, and tumors.

Early postoperative ultrasound of kidney transplants: evaluation of contrast medium dynamics using time-intensity curves.

OBJECTIVE: To evaluate kidney recipients in the early posttransplant phase by semiquantitative analysis of the arterial arrival of ultrasound (US) contrast medium using time-intensity curves. PATIENTS AND METHODS: Twenty-two kidney recipients underwent US examination after intravenous bolus administration of 2.4 ml of US contrast medium (SonoVue, Bracco Altana) 5 to 7 days after transplantation. The examinations were performed with the Aplio US system (Toshiba) and a 3.5-MHz wideband transducer using contrast harmonic imaging at a low mechanical index of 0.1. Arterial arrival was documented digitally over 60 sec (image repetition rate: 10 images per sec) for subsequent evaluation of contrast medium kinetics in the main renal artery, interlobar artery, subcapsular area, and renal vein using the system's integrated time-intensity curve (TIC) software. The increase, decrease, and percentage enhancement factor were calculated from the curves. Four patients were excluded from analysis because of perirenal hematoma (n = 3) or a polar perfusion loss demonstrated by power Doppler (n = 1). RESULTS: Twelve of the remaining 18 patients assigned to the nonrejection group showed an uneventful clinical course. These had uniform TICs with an early and steep increase of similar magnitude in the main renal artery (11.7 +/- 4.5 intensity units/sec), interlobar artery (8.7 +/- 4.6 intensity units/sec), and subcapsular area (8.3 +/- 3.7 intensity units/sec) followed by a washout and subsequent plateau phase. Six patients showed histologically proven acute rejection on day 5 or 6 after transplantation (rejection group). This group had a delayed (time to peak in the subcapsular area: 32.9 +/- 8.3 sec in the rejection group versus 20.9 +/- 4.7 sec in the nonrejection group, p < 0.05) and smaller subcapsular percentage increase (41.2 +/- 21.9 % versus 114.4 +/- 59.8 %, p < 0.05). In the rejection group the subcapsular area (3.8 +/- 2.3 intensity units/sec) showed a less pronounced increase than the main renal artery (7.9 +/- 5.9 intensity units/sec) and interlobar artery (8.7 +/- 3.8 intensity units/sec). The RI in the rejection group was in the normal range at the time of contrast-enhanced US (day 5: 0.78 +/- 0.06) and increased to abnormal levels in the further course (day 7: 0.94 +/- 0.09). CONCLUSIONS: Quantitative determination of arterial arrival of an US contrast medium in the early phase after kidney transplantation is possible. This new US procedure might identify acute rejection earlier than conventional techniques.

[Laparoscopic transperitoneal donor nephrectomy. Technique and results]. / Die laparoskopische transperitoneale Donornephrektomie. Technik und Ergebnisse.

Living donor kidney transplantation is one possibility to meet the growing demand for organs in patients with chronic renal failure. In 1995 the first laparoscopic living donor nephrectomy (LDN) was performed in the United States. More than 100 transplant centers worldwide perform LDN. The expectations of a larger number of willing organ donors were fulfilled due to the less traumatic operation. Meanwhile, several techniques exist to retrieve a kidney laparoscopically, including the trans- or retroperitoneal, strictly laparoscopic, or hand-assisted approach. From February 1999 to September 2002, 63 strictly laparoscopic, transperitoneal LDNs were performed at the Department of Urology of the Charité University Hospital, Berlin. Warm ischemic time was 148 s (105-360) and operating time was 203 min (110-305). Intraoperative complications were due to insufficient closure of the vessels in four patients. Mean postoperative hospital stay was 5.7 days (3-9). One year after LDN, renal function as well as creatinine levels of the recipient showed no difference compared to the organs harvested via the approach at our department prior to implementation of LDN. Strictly laparoscopic transperitoneal donor nephrectomy is a safe method for kidney retrieval and ensures excellent graft function.

[Laparoscopic living donor nephrectomy of kidneys with multiple renal vessels]. / Multiple Nierengefässe bei der laparoskopischen Lebendnierenspende.

Due to the increasing waiting time for transplantation of a cadaveric kidney, living donor kidney transplantation is an increasingly oncoming issue. Laparoscopic donor nephrectomies (LDN) have been performed since 1995 and presently more than 100 transplant centers offer this minimally invasive surgical approach. The advantages for the donor of less pain, shorter hospital stay, earlier return to work, better cosmetic results in combination with an organ function equal to open donor nephrectomy are the reasons for an enormous increase in LDN. Since up to 30% of the donor kidneys have multiple vessels for blood supply, an increase of these organs for LDN can be expected. We performed a retrospective study of LDN at our center and compared donors with multiple vs single vessel supply. From February 1999 to September 2002, 63 LDN were performed at the department of Urology, Charité University Hospital, Berlin. A comparison between 18 donor kidneys with multiple vessel supply and 45 donor organs with single vessels showed no difference for the time of laparoscopic explantation (207 vs 201 min, p=0.4) or the warm (166 vs 148 s, p=0.2) and cold ischemic times (117 vs 103 min, p=0.66). As could be expected, the mixed ischemic time, i.e., the time for anastomosis of the kidney with the recipient's vessels, showed a significant difference (53 vs 46 min, p=0.02). Intra- and postoperative complication rates for donors and recipients were not different in both groups. Laparoscopic donor nephrectomy for kidneys with multiple vessels is feasible and safe for donor and recipient.