Duplex Doppler evaluation of renal allograft dysfunction: Doppler signal quantitation and pathologic correlation

The value of quantitative duplex Doppler sonography in discriminating the different possible causes of renal transplant dysfunction was prospectively studied in 60 patients during 65 episodes of renal function impairment. Final diagnosis at histology was acute rejection (n: 30), acute tubular necrosis (n: 4), cyclosporin nephrotoxicity (n: 16) and chronic rejection (n: 15). Duplex sonography was done the day a percutaneous biopsy was taken and before any therapy was started. Arterial Doppler signals obtained from the segmental, interlobar and arcuate arteries were both morphologically and quantitatively analysed. For quantitative analysis we used the resistive index as proposed by Pourcelot on the one hand, and introduced a variant resistive index on the other hand. Morphological analysis yielded no discriminative value. Comparing both quantitative methods--the resistive index of Pourcelot and the variant resistive index--clearly higher specificities--71% using the variant resistive index, 28% using the resistive index of Pourcelot--for excluding acute rejection from the other possible causes of renal function impairment could be achieved. A nephrectomy was done on 7 patients with severe transplant dysfunction. Microangiographies performed on these nephrectomy specimens were correlated with previous Doppler studies and with histology.     

多带宽DTI-IVIM技术评估肾移植术后早期移植肾功能受损的价值

目的 探讨多带宽扩散张量成像-体素内不相干运动(multiband DTI-IVIM)技术评估肾移植术后早期不同程度受损移植肾功能的价值。方法 前瞻性收集异体肾移植术后2~4周病人92例行常规MRI、multiband DTIIVIM MRI检查。根据估算肾小球滤过率(eGFR)将病人分为3组:组1,eGFR≥60 mL/(min·1.73 m^2)(45例);组2,30 mL/(min·1.73 m^2)≤eGFR<60 mL/(min·1.73 m^2)(27例);组3,e GFR<30 mL/(min·1.73 m^2)(20例)。测量移植肾皮髓质的表观扩散系数(ADC)、单纯扩散系数(ADCslow)、微循环灌注系数(ADCfast)、灌注分数(f)、各向异性分数(FA)。采用配对t检验分析比较皮髓质间各参数值差异;采用单因素方差分析比较组间各参数值的差异;采用Pearson相关分析研究移植肾各参数值与eGFR间的相关性以及皮髓质FA值与其他各参数值的相关性。结果 组1肾皮质FA值低于髓质,余参数值高于髓质(P<0.05),组2、组3的ADCslow、ADCfast值及组2的f值皮髓质间差异无统计学意义(P>0.05)。组2肾皮髓质ADC、ADCslow、皮质f值及髓质FA值均低于组1(P<0.05)。组3肾皮髓质ADC、髓质ADCslow及髓质FA值均低于组2(P<0.05)。组3肾皮髓质ADC、ADCslow、f值、皮质ADCfast值及髓质FA值均低于组1(P<0.05)。各参数中,髓质FA值对组1和组2、组2和组3、组1和组3鉴别诊断效能最高(AUC分别为0.855、0.831、0.983);联合DTI-IVIM参数鉴别各组的能力最高(AUC分别为0.954、0.885、1.000)。除髓质ADCfast值、f值及皮质FA值外,移植肾各参数值与eGFR均呈中度正相关(r值为0.333~0.707,P<0.05)。髓质FA值与皮髓质ADC值、皮髓质ADCslow值及髓质f值均呈中度正相关(r值为0.335~0.526,P<0.05)。结论 multiband DTI-IVIM联合DTI和IVIM技术,可以评估并鉴别移植术后早期不同功能状态的移植肾功能。     

彩色多普勒超声在移植肾肾小管坏死中的应用

目的：为了探讨彩色多普勒血流成像在移植肾术后肾小管坏死中应用的价值。方法：我们对14例肾移植术后肾小管坏死的病例进行回顾性的分析，并对经过连续的动态的彩色多普勒超声的观察进行总结。结果：发现14例中10例一开始是急性肾小管坏死，其余4例由急性肾排异转变成肾小管坏死，通过分析提供了准确病因诊断依据，并指明导临床治疗。     

肾移植血流灌注的影像学研究进展

肾移植术后并发症主要有急性排斥反应、急性肾小管坏死、慢性排斥反应等,其病理改变可引起移植肾血流灌注的变化,此为国内外研究的热点.影像学检查在肾移植术后并发症的监测中发挥重要的作用,目前主要以超声作为移植肾的基本检测手段,磁共振成像作为进一步的补充检查.三维超声容积自动测量技术和超声成像是目前发展较快的超声新技术,磁共振灌注成像用于检测移植肾早期病变作为研究热点,三者在评价移植肾血流灌注方面具有非常重要的作用,有望使移植肾术后并发症的检测从定性、半定量水平发展到定量水平,提高影像学检查的特异性和敏感性,为临床提供更进一步的帮助.     

肾移植血流灌注的影像学研究进展

肾移植术后并发症主要有急性排斥反应、急性肾小管坏死、慢性排斥反应等,其病理改变可引起移植肾血流灌注的变化．此为国内外研究的热点。影像学检查在肾移植术后并发症的监测中发挥重要的作用,目前主要以超声作为移植肾的基本检测手段,磁共振成像作为进一步的补充检查。三维超声容积自动测量技术和超声成像是目前发展较快的超声新技术,磁共振灌注成像用于检测移植肾早期病变作为研究热点,三者在评价移植肾血流灌注方面具有非常重要的作用。有望使移植肾术后并发症的检测从定性、半定量水平发展到定量水平,提高影像学检查的特异性和敏感性,为临床提供更进一步的帮助。     

持续肾脏替代疗法在肝移植术后肾功能衰竭中的应用

目的探讨持续肾脏替代疗法对肝移植术后肾功能衰竭的治疗效果。方法将持续肾脏替代疗法应用于7例肝移植术后肾功能衰竭病人,平均治疗36.1h,置换液以前稀释方式输入,流量为2～4L/h,血流量150～250ml/min,采用普通肝素抗凝。结果7例病人中4例好转,2例死亡,1例因经济原因自动出院;所有患者治疗中血流动力学稳定,血BUN及血Cr下降明显,具有显著性差异(P<0.05),但血中胆红素下降不明显(P>005);治疗中未发现明显的副作用。结论持续肾脏替代疗法对肝移植术后肾功能衰竭有改善预后的作用,患者耐受性好,是抢救肝移植术后肾功能衰竭有效手段之一。     

Hepatic vein stenosis after living donor liver transplantation: evaluation with Doppler US

PURPOSE: To determine the spectral Doppler ultrasonographic (US) findings that would indicate hepatic vein stenosis after living donor liver transplantation (LDLT). MATERIALS AND METHODS: The authors retrospectively reviewed postoperative Doppler US images of the hepatic veins in 113 consecutive patients who underwent LDLT. Doppler US was performed 1-25 times (mean, 5.2 times) during 1-433 days after LDLT. Nineteen patients who were inadequate for analysis were excluded; thus, 94 patients (72 male patients and 22 female patients; mean age, 40 years) were included in the study. Patients with more than 10 mm Hg of pressure gradient between the hepatic vein and the inferior vena cava were considered to have substantial hepatic vein stenosis (stenosis group). Those without substantial stenosis (control group) included patients with no clinical or radiologic evidence of hepatic vein stenosis for at least 3 months after LDLT. The wave pattern and peak flow velocity of the hepatic veins were compared between the groups. RESULTS: Five patients (5%) had substantial hepatic vein stenosis: three had persistent monophasic wave patterns at all US examinations, and two had monophasic wave patterns at most US examinations and biphasic or triphasic wave patterns at 6- and 9-day follow-up examinations. In the control group, 52 (58%) of 89 patients had a persistent triphasic or biphasic wave pattern and 37 (42%) had a monophasic wave pattern at one or more US examinations; this included two patients with persistent monophasic wave patterns. A monophasic wave pattern was more frequent in the stenosis group than in the control group (P =.015). There was no significant difference between the velocities of the hepatic veins in the stenosis group (22.3 cm/sec +/- 9.6 [SD]) and those in the control group (37.5 cm/sec +/- 20.3) (P =.14). CONCLUSION: A persistent monophasic wave pattern on Doppler US images of the hepatic veins is suggestive of, but not specific for, substantial hepatic vein stenosis after LDLT. A persistent triphasic wave pattern on Doppler US images can exclude the possibility of substantial stenosis.     

Metastatic malignant tumor in native kidney with acquired cystic disease after renal transplantation

Patients on long-term hemodialysis frequently develop Acquired Cystic Renal Disease (ACRD). When hematuria or flank pain occurs, the possibility of malignant renal tumors should be investigated. We present an ACRD patient who received a kidney transplant and developed malignancy in a native kidney, the first manifestation being bone metastases, and discuss the role of CT in evaluating these patients.     

Ultrasonographic evaluation of renal transplantation.

Ultrasonography of the renal transplant is still a key screening examination for transplant dysfunction. The addition of Doppler technology has permitted screening for hemodynamic alterations. Ambitious researchers predicted that these hemodynamic profiles would permit the differentiation of rejection from other complicating factors; however, recent research and clinical experience has shown this to be ineffective. Imaging identification of a dilated collecting system identifies the patient population that should undergo a Whitaker procedure. Identification of large or increasing fluid collections helps focus attention to possible hemorrhage or urine leak. Similarly, the ultrasonographic identification of a lymphocele as the cause of leg edema or hydronephrosis rapidly focuses surgical treatment. Doppler evaluation of hemodynamics must be performed on all renal transplant recipients. Although the role of the resistive index in predicting rejection has been minimized lately, numerous vascular complications, if untreated, would result in loss of the kidney. Doppler sonography identifies those patients who would benefit most from renal arteriography. The evaluation of renal morphology on the basis of ultrasonography alone has little role in predicting the cause of transplant dysfunction. We continue to evaluate renal size and to correlate it with the clinical presentation as well as resistive index to defer patients from biopsy if a more obvious cause of dysfunction is identified.     

Ultrasound and computed tomographic evaluation of renal transplantation

Ultrasound and computed tomography are very useful in the diagnosis of parenchymal and urologic abnormalities after renal transplantation. The increased use of Doppler duplex sonography will further enhance the role of ultrasound in the evaluation of patients with kidney transplants. Computed tomography is of particular value in the setting of suspected posttransplant malignancy. Both imaging techniques can be used to guide diagnostic and therapeutic interventional radiologic procedures.     

Role of duplex Doppler and power Doppler sonography in transplanted kidneys with acute renal parenchymal dysfunction

The limited work published on the comparison of power Doppler sonography (PDS) and duplex Doppler sonography (DDS) in the assessment of acute renal allograft dysfunction has shown contradictory results. We compared the role of DDS and PDS in renal transplant recipients developing acute renal parenchymal dysfunction and correlated these findings with kidney biopsy, which was taken as the gold standard. Thirty post-renal transplant patients with acute graft dysfunction underwent Doppler sonography, DDS and PDS using an HDI 5000 ATL machine. Patients who developed graft dysfunction as a result of vascular, obstructive or other non-parenchymal causes were excluded. All patients underwent an allograft biopsy within 72 h of the sonography. Based on the biopsy findings, 24 patients were categorized as having acute rejection, and six patients as having no rejection. The overall sensitivity, specificity and accuracy of DDS for evaluation of graft dysfunction were 54.17, 33.33, and 50.00%, respectively, and that for PDS were superior with 87.50, 33.30, and 76.67%, respectively. The low specificity can be partially attributed to the small number of cases without rejection in our study population. We conclude that PDS is superior to DDS in screening patients with acute parenchymal renal dysfunction post-transplant. However, a normal PDS examination does not exclude the presence of acute rejection. Power Doppler sonography is a useful screening test for diagnosing acute rejection but a renal allograft biopsy remains the gold standard for diagnosis of this condition.     

Vesicoureteric reflux after renal transplantation

The results of micturating cystography are discussed in an unselected group of 22 patients with functioning renal transplants. Reflux occurred into the donor ureter in 16 patients but could not be incriminated as a cause of graft failure, hypertension, proteinuria, or recurrent urinary infections. There is probably little point in using an elaborate technique for implantation of the donor ureter to ensure a competent vesicoureteric junction.     

肾移植术后输尿管狭窄病因及治疗策略分析

目的探讨肾移植术后输尿管狭窄的病因及外科治疗方法,并分析其治疗效果。方法回顾性分析北部战区总医院泌尿外科自2016年1月至2018年5月收治的9例肾移植输尿管狭窄患者的临床资料。内镜微创治疗5例,行开放手术2例,移植肾长期造瘘2例。术后对9例患者进行随访。结果 5例行内镜治疗患者术中均未发生移植肾输尿管黏膜撕脱或断裂,2例行开放手术患者术中均未发生明显的出血或移植肾损伤。术后9例患者均获6～16个月随访,术后2例需长期更换肾造瘘管,1例输尿管再植术后再发狭窄需长期更换输尿管支架1例,6例治愈。结论移植肾输尿管的狭窄多为输尿管末段狭窄所致。内镜微创治疗具有创伤小,术后恢复效果佳等优点。     

Acute renal dysfunction after major arteriography

The incidence of acute renal dysfunction (ARD) after major arteriography was evaluated by assessment of the change in serum creatinine in 364 patients undergoing arteriography. Major arteriography was defined as abdominal aortography, abdominal aortography with lower-extremity runoff, aortic arch studies, or aortic arch plus selective carotid angiography. The influence of the volume of contrast material received, hydration, and associated risk factors was evaluated. In the entire group, the frequency of postarteriographic ARD was 7.1%. Although most patients recovered, 1.4% required renal dialysis. The frequency of renal dysfunction was significantly higher in patients with preexisting renal disease (14.8%), and 3.7% of these patients went on to require dialysis. In the total group and in those with normal renal function prearteriographically, the frequency of ARD was found to be related to the volume of iodinated contrast material received. Hydration before, during, and after angiography did not prevent this complication. Several risk factors, namely preexisting renal disease, advanced age, volume of contrast material used, type of study performed, diabetes mellitus, and coexistent heart disease were found to be associated with a statistically significant increased risk of postangiographic ARD.