Hypoechoic renal pyramids: sonographic visualization in older children and young adults.

The frequency and degree of visualization of medullary pyramids in a normal population, aged 10-29 years, was analyzed. Hypoechoic pyramids were visualized in 42% of right kidneys in subjects aged 10-18 years and in 27% of subjects aged 19-29 years. Prominently hypoechoic pyramids, mimicking the appearance of neonatal kidneys, were seen in an additional 34% of subjects aged 10-18 years and in 16% aged 19-29 years. Prominent pyramids were present in 50% of subjects with renal cortical echogenicity (RCE) equal to liver, but also in 21% of subjects with RCE less than liver. Our study expands the age at which prominently hypoechoic medullary pyramids can be considered a normal finding. This may relate to recent improvements in ultrasound technology.     

Sonographic assessment of normal renal parenchymal and medullary pyramid thicknesses among children in Enugu,Southeast, Nigeria

BackgroundRenal parenchymal thickness (RPT) and renal medullary pyramid thickness (MPT) are important renal size parameters. This study was aimed at establishing normograms for RPT and MPT with respect to age and somatometric parameters among children.MethodsThis was a cross sectional study done in Enugu, Nigeria between May 2013 and April 2014. The subjects were 512 children aged 1–17 years scanned with ultrasound equipment with 3.5 MHz and 5 MHz curvilinear transducers. The RPT was measured perpendicularly to the long axis of the kidney from the medullary papilla to the renal capsule and MPT was measured from the apex to the base of the medullary pyramid on the same plane. The age and somatometric parameters of the subjects were recorded.ResultsThe mean ± SD of RPT and MPT for the right kidney were 12.62 ± 1.67 mm and 7.10 ± 0.92 mm and the left kidney were 12.81 ± 1.7 and 7.23 ± 0.94 mm respectively. There was a significant difference between the right and left RPT and MPT (p < 0.05). The right and left RPT correlated strongly with age, body surface area (BSA), height, and weight but moderately with body mass index (BMI). A moderate positive correlation was observed between MPT and age, BSA, height, and weight. However, a weak correlation was observed between MPT and BMI.ConclusionNormograms of RPT and MPT in relation to age could be useful for grading hydronephrosis in children.     

Sonographic detection of renal changes in pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degeneration of elastic tissue, with calcification of the tonaca media of the arteries, and typical yellowish papules of the skin. We report the sonographic findings observed in a young patient with PXE at the level of the kidneys: fine hyperechogenic spots suggesting small calcifications were diffuse at the corticomedullary junction; however, normal waveforms were obtained at the level of intraparenchymal renal vessels. The presence of this structural pattern in a young patient with dermatologic abnormalities should lead to the consideration of PXE in the differential diagnosis list.     

Duplex doppler ultrasound in determination of renal artery stenosis

Twenty-six cases of renal artery stenosis were evaluated with Doppler ultrasound using the pulsatile flow index (PFI). To establish normal values, the PFI in 60 renal arteries in 30 healthy volunteers was obtained. Normal values by PFI ranged between 0.48 and 0.71 (mean ± SD: 0.6 ± 0.06). In renal artery stenosis the PFI range was 0.72–0.79. The normal upper limit was 0.71. The PFI failed in three patients; however, an ultrasound examination showed secondary renal disease (two patients with stenosis on both sides with a shrunken kidney on one side, and one patient with hypernephroma on the opposite side). The PFI was normal (14 of 14 patients) in patients without angiographic evidence of stenosis or after successful dilatation.     

Contemporary imaging techniques for the diagnosis of renal artery stenosis

Renal artery stenosis (RAS) is a potentially curable cause of renovascular hypertension (RVH) and is caused by either atherosclerosis or fibromuscular dysplasia (FMD) in the vast majority of patients. Although intra-arterial digital subtraction angiography (IA-DSA) is still considered the standard of reference test for the anatomical diagnosis of RAS, noninvasive techniques such as MR angiography, CT angiography, and color-aided duplex ultrasonography are promising alternatives that also allow functional characterization of RAS. We provide an overview of these techniques and discuss their relative merits and shortcomings. Analysis of high-quality studies shows that both MR and CT angiography are significantly more accurate for the diagnosis of at least 50% atherosclerotic RAS than ultrasonographic techniques. The primary strength of ultrasonography at present is its suggested ability to predict functional recovery based on preinterventional resistance index measurements. A still unresolved issue is the detection of FMD. Because missing RVH may have serious consequences the most important requirement for a screening test is that it has high sensitivity.     

CT相对强化比值鉴别肾嗜酸性细胞瘤与肾透明细胞癌的应用价值

目的:探讨CT相对强化比值(病灶/肾皮质密度比值)鉴别肾嗜酸性细胞瘤(RO)与肾透明细胞癌(RCC)的应用价值.方法:回顾性分析经手术病理证实的14例RO和32例RCC的CT强化特征.分别测量两组病例CT增强各时相病灶强化区域及相邻肾皮质密度,比较各时相病灶CT值和病灶/肾皮质密度比值.采用独立样本t检验及卡方检验对测量结果进行统计学分析.结果:RCC于CT增强皮质期、髓质期和肾盂期测得的病灶CT绝对值均高于RO,但差异无统计学意义(P均＞0.05);27例RCC(27/32,占84％)皮质期病灶/肾皮质密度比值＞1,仅1例RO(1/14,占93％)病灶/肾皮质密度比值＞1,两者间差异具有统计学意义(P＜0.05);10例RO(10/14,占71％)髓质期病灶/肾皮质密度比值高于皮质期,呈“延迟强化”表现,仅1例RCC(1/32,占3％)髓质期病灶/肾皮质密度比值高于皮质期,呈“延迟强化”表现,两者间差异具有统计学意义(P＜0.05).以皮质期病灶/肾皮质密度比值＜1为标准,诊断RO的敏感度、特异度、阳性预测值、阴性预测值、准确性分别为93％、84％、72％、84％和87％;以髓质期病灶/肾皮质密度比值高于皮质期为标准,诊断RO的敏感度、特异度、阳性预测值、阴性预测值、准确性分别71％、97％、91％、91％和89％.结论:应用CT相对强化比值(病灶/肾皮质密度比值)分析法有助于鉴别RO与RCC.     

经皮肾镜手术前后肾阻力指数变化在肾功能中的应用评价

目的：应用经皮肾镜手术前后肾阻力指数（RI）的变化来评价肾功能。方法采用随机、平行对照的临床研究方法,对纳入本研究的40例患者,记录经皮肾镜手术前、手术后0.5 h、手术后2周时双侧肾上、中、下段肾叶间动脉阻力指数,以及血液肌酐、尿素氮数据,分析肾动脉阻力指数与肾功能变化的关系。结果①患侧肾在经皮肾镜术前2 h与术后0.5 h叶间动脉RI值相比较,差异有统计学意义（t=2.72,P＜0.05）,术后1周的叶间动脉RI值相比较,差异有统计学意义（t=3.57,P＜0.05）,而健侧肾在经皮肾镜术前与术后0.5 h叶间动脉RI值相比,差异无统计学意义（t=1.63,P＞0.05）,而与术后2周叶间动脉RI值相比,差异有统计学意义（t=3.31,P＜0.05）;②患者的术前2 h血液中肌酐与术后0.5 h相比,差异无统计学意义（t=1.33,P＞0.05）,而与术后1周相比,差异有统计学意义（t=3.86,P＜0.05）,患者的术前2 h血液中尿素氮与术后0.5 h相比,差异无统计学意义（t=2.01,P＞0.05）,而与术后1周相比,差异有统计学意义（t=3.57,P＜0.05）;③患者健侧肾术前、术后RI值与肌酐、尿素氮变化无相关性,而患侧肾术前、术后RI值与肌酐、尿素氮的变化呈负相关（r=-0.37,P＜0.05）。结论可以应用经皮肾镜手术前后肾RI的变化来评价肾功能的变化,为泌尿科微创取石手术提供临床依据。     

Cystic renal tumors: US and CT findings

Cystic renal tumors represent a variety of lesions in which both solid and liquid components coexist. These lesions may be either benign or malignant and include the multilocular cystic nephroma (MCN), the renal cell carcinoma (RCC), and the papillary adenocarcinoma (PAC). The MCN is a rare neoplasm formed of multiple loculated cystic masses divided by septa. The tumor is benign, although there are some rare reports of malignant cases. The RCC and the PAC may appear with cystic patterns. This is rather uncommon for the RCC, which inside has a unilocular or multilocular cystic appearance, if the necrotic component is large. PAC is an infrequent renal tumor, which has a greater tendency to appear as a large mass with a unilocular large cystic space. The ultrasonography (US) and computed tomographic (CT) features of 27 cystic tumors are presented. Both US and CT allowed the recognition of the cystic components, the septa, and the vegetations. The two imaging techniques made it possible to distinguish the tumors into “unilocular” and “multilocular” masses: the former correspond to RCC and PAC, the latter to MCN and RCC. CT added some information on calcified or partially calcified tumors. CT more than US enabled the differentiation between the malignant RCC and the benign MCN for which conservative surgery may be indicated. The two techniques did not allow the differentiation between RCC and PAC, which has different prognostic behavior.     

肾脏嗜酸细胞腺瘤的CT征象分析与鉴别诊断

目的：探讨肾脏嗜酸细胞腺瘤（Renal Oncocytoma，RO）的CT表现，以提高对其诊断的准确性。方法：回顾性分析经病理证实的12例RO的CT资料，全部经MSCT多期检查，包括平扫、增强皮质期、髓质期和排泄期（5例）。结果：病灶全部单发，7例位于左肾，5例位于右肾，最大径2．0-11．6cm，平均5．8em，小于3．0cm者3例。皮质期，10例病灶明显强化，其中8例强化低于肾皮质，2例强化接近于肾皮质。髓质期，7例强化下降并低于肾脏髓质，3例持续强化但在排泄期见密度开始下降。2例在皮质期至排泄期表现为持续性强化。6例见星芒样瘢痕，8例见完整包膜，3例见钙化。结论：大部分RO为富血供。增强后实质部分均匀强化，囊变或坏死罕见，有助于与肾透明细胞癌及肾嫌色细胞癌等相鉴别。     

肾恶性肿瘤肾外供血动脉的来源及临床意义

目的研究肾恶性肿瘤肾外动脉供血的形成机制，以指导介入治疗。方法对141例肾恶性肿瘤患者，常规进行腹主动脉造影及选择性可疑供血动脉造影，分析其肾外供血动脉的特征及形成机制。结果141例患者中51例有肾外供血动脉（共87支），这些患者肿瘤均突破肾包膜；90例无肾外供血动脉，其中50例肿瘤突破肾包膜，40例肿瘤未突破肾包膜，两者差异有统计学意义（X^2=31．64，P＜0．01）。肾外供血动脉的来源与肿瘤发生的部位有关。结论明确肾恶性肿瘤肾外供血动脉的来源，对于指导临床治疗具有重要的意义。     

Percutaneous angioplasty for atherosclerotic renal artery disease: Effect on renal function in azotemic patients

Purpose We studied the effect of percutaneous transluminal renal angioplasty (PTRA) on renal function in azotemic patients with atherosclerotic renal artery stenosis.Methods The results of PTRA were analyzed retrospectively in 40 patients. There were 61 stenoses, 54 of which received balloon angioplasty; 7 had stent placement during the initial procedure, 6 for recurrent stenosis 6–18 months after PTRA.Results Technical success was achieved in 95% of cases. The complication rate was 15%, compared to 6% in nonazotemic patients. Mean creatinine rose from 1.9 ± 0.15 mg/dl (mean ± SEM) to 2.4 ± 0.17 mg/dl during the year before PTRA, stabilizing at 2.5 ± 0.57 mg/ dl for 1 year after PTRA. PTRA was clinically successful in 60% of patients; 40% showed further deterioration of renal function. Clinical failure was associated with residual renal artery stenosis and presence of intermittent claudication.Conclusion We conclude that PTRA helps salvage renal function in patients with azotemia and atherosclerotic renal artery stenosis.     

Transverse fusion of the renal pelves and single ureter

We present a case of a rare renal anomaly in which the 2 kidneys (separate or fused across the midline) are drained by a common renal pelvis and ureter. Previously reported cases have been reviewed and are classified in 3 groups according to their anatomical features. The lesion is associated with some frequency with imperforate anus, sacral and other vertebral defects, neurogenic bladder, vesicoureteral reflux, upper tract dilatation, and urinary tract infections.     

Multidetector CT angiography of renal vasculature: normal anatomy and variants

Knowledge of the variations in renal vascular anatomy is important before laparoscopic donor or partial nephrectomy and vascular reconstruction for renal artery stenosis or abdominal aortic aneurysm. Recently, multidetector computed tomographic (MDCT) angiography has become a principal imaging investigation for assessment of the renal vasculature and has challenged the role of conventional angiography. It is an excellent imaging technique because it is a fast and non-invasive tool that provides highly accurate and detailed evaluation of normal renal vascular anatomy and variants. The number, size and course of the renal arteries and veins are easily identified by MDCT angiography. The purpose of this pictorial essay is to illustrate MDCT angiographic appearance of normal anatomy and common variants of the renal vasculature.     

Arteriovenous fistulas in renal transplants: Color Doppler ultrasound observations

One hundred twenty-six new renal transplants were scanned regularly with color Doppler ultrasound (CDU). In 22 (17.5%) of the grafts there was evidence of postbiopsy arteriovenous (AV) fistula during the first 6 months postoperatively. In 14 cases the fistula closed spontaneously. In the remaining eight, the fistula was still present up to 24 months later (four cases) or until the graft failed (four cases). Additionally, 163 established grafts were scanned for evidence of vascular abnormality. AV fistulas were observed in 15 grafts (8%). Circulatory complications of fistulas observed include vascular steal and a possible association with graft vein and artery stenosis.     

Rare variations in renal anatomy and blood supply: CT appearances and embryological background. A pictorial essay

Helical CT angiography is increasingly used for the evaluation of the kidneys and the renal vessels. Knowledge of the potential variants in renal and renal vascular anatomy and of their appearances on helical CT are thus indispensable for radiologists who perform and interpret such examinations. We report six cases of anatomic variants that we encountered in our tertiary referral centre over the past 5 years, during which time we have performed 4850 helical CT angiograms, including 1432 renal artery examinations. These represent rarer anomalies in renal vascularization, most of which were associated with renal malformations (horseshoe kidney with or without cortical torsion, renal malrotation, single kidney, and thoracic origin of a renal artery). We present the helical CT findings and discuss the possible embryological mechanisms and the practical implications of these abnormalities for the radiologist. Received: 7 March 2000 Revised: 16 August 2000 Accepted: 17 August 2000     

Angiomyolipoma arising in the renal sinus: A difficult radiologic diagnosis

We report a case of angiomyolipoma (AML) occurring in the renal sinus evaluated by intravenous urography (IVU), renal ultrasound (US), angiography, and computed tomography (CT). Imaging features of this lesion are identical to AMLs elsewhere, but preoperative diagnosis was complicated by the unusual occurrence of the tumor in this location in a patient with abdominal pain. Accurate preoperative diagnosis will allow tumorectomy or conservative management.     

Tumours of the genito-urinary tract in renal transplant recipients: clinical and radiographic findings

In order to study the clinical and radiological manifestations of post-transplantation malignant genito-urinary tumours in kidney recipients, we reviewed nine cases of genito-urinary neoplasms among 65 malignancies which developed in 61 of 620 kidney recipients. Ultrasound (US) and CT examinations were available in all the cases and MRI imaging in three. For each patient we reviewed the date of transplantation, immunosuppressive therapy, pathology and surgical reports and relevant radiographic studies. We determined tumour volume, the presence of necrosis and tumour extension. The malignant tumours included B-cell non-Hodgkin lymphomas of the native kidney (2) and urinary bladder (1), renal cell carcinoma (1), urotheliomas of the renal pelvis (1), ureter (1) and bladder (1), epidermoid carcinoma of the renal pelvis (1) and embryonal testicular carcinoma (1). Two of the three lymphomas developed in cyclosporine-treated recipients and regressed after reduction of the cyclosporine dose. The lymphomas presented as solid masses with necrosis visible on T2-weigthed MRI images. Other non-lymphomatous neoplasms were characterised by a large tumour volume and advanced local and regional extension. Five patients died within 2 years after diagnosis. It is concluded that the high incidence of malignancies (9.8 %), especially of the genito-urinary tract (1.4 %), and their advanced stage warrant radiographic follow-up studies. Correspondence to: M.-F. Bellin     

Lifespan changes in multi-tasking: concurrent walking and memory search in children, young, and older adults

We investigated dual-task performance of cognitive (semantic fluency) and sensorimotor tasks (walking) in 120 children and adults from four age groups (9-year olds, M=9.52 years; 11-year olds, M=11.51 years; young adults, M=25.34 years; older adults, M=64.28 years; N=30 per group). Distances walked during 90 s and numbers of category exemplars generated in the semantic fluency task showed an inverted U-shape function with age. In line with general resource models proportional dual-task costs in walking also showed a U-shaped relation as a function of age with pronounced decrements in the youngest and oldest groups. Only 9-year olds showed significant costs in the cognitive task. Individual differences in single-task performance accounted for more than half of the variance in dual-task performance. Reliable age-related residual variance implicated additional factors particularly in children's developing multi-tasking performances.