Preoperative psychological characteristics affecting mid-term outcome after bariatric surgery: a follow-up study.

BACKGROUND: The purpose of this study was to investigate the relationship between preoperative psychological factors and percentage of total weight loss (%TWL) after laparoscopic Roux-en-Y gastric bypass (LRYGB) to identify possible psychological therapy targets to improve the outcome of bariatric surgery. METHODS: Seventy-six patients completed the Hamilton's Anxiety and Depression Scales (HAM-A, HAM-D) and Toronto Alexithymia Scale (TAS-20) the day before surgery (T0). The pre-operative body weight and the %TWL at 3 (T1), 6 (T2), and 24-30 (T3) months were collected. RESULTS: At T3, depressed and alexithymic patients showed a lower %TWL compared to non-depressed patients (p = 0.03) and to non-alexithymic patients (p = 0.02), respectively. Finally, patients who had at least one of the three analyzed psychological factors showed less weight loss, at T2 (p = 0.02) and T3 (p = 0.0004). CONCLUSIONS: Psychological factors may also affect long-term outcome of bariatric surgery. This study shows an association between alexithymia/depression pre-operative levels and the weight loss at 30 months'follow-up after bariatric surgery. LEVEL OF EVIDENCE: Level III, longitudinal cohort study.

Standardized Protocol for Hemodialysis Vascular Access Assessment: The Role of Ultrasound and ColorDoppler.

INTRODUCTION: Ultrasound and colorDoppler technique, which is relatively inexpensive, rapid, non-invasive and repeatable is a powerful tool used for early diagnosis of vascular access (VA) complications in hemodialysis patients. To date a standard and widely comprehensible echocolorDoppler (ECD) protocol is not available. MATERIALS AND METHODS: A simple step-by-step protocol based on anatomical and hemodynamic parameters of VA has been developed during a 3-years VA ECD follow-up. It consists of an ECD study scheme. The algorithm created involves the calculation of brachial artery flow, description of artero-venous and/or graft-vascular anastomosis and efferent vessel and/or graft. RESULTS: The algorithm allows to formulate a medical report that takes into account both anatomic and hemodynamic parameters of the VA. Reduction of complications and the prevention of chronic complications as well as the early detection of acute problems were achieved. DISCUSSION AND CONCLUSION: The creation of a step-by-step protocol may simplify the multidisciplinary management of VA, its monitoring and the early diagnosis of its complications.

The key role of color Doppler ultrasound in the work-up of hemodialysis vascular access.

Vascular access (VA) is the lifeline for the hemodialysis patient and the native arterio-venous fistula (AVF) is the first-choice access. Among the different tests used in the VA domain, color Doppler ultrasound (CD-US) plays a key role in the clinical work-up. At the present time, three are the main fields of CD-US application: (i) evaluation of forearm arteries and veins in surgical planning; (ii) testing of AVF maturation; (iii) VA complications. Specifically, during the AVF maturation, CD-US allows to measure the diameter and flow volume in the brachial artery and calculate the peak systolic velocity (PSV) of the arterial axis, anastomosis and efferent vein, to detect critical stenosis. The borderline stenosis, revealed by the discrepancies between access flow rate and PSV, should be followed up with subsequent tests to detect progression of stenosis; the cases with significant changes in brachial flow should be referred to angiography. In conclusion, clinical monitoring remains the backbone of any VA program. CD-US is of utmost importance in a patient-centered VA evaluation, because it allows the appropriate management of all aspects of VA care. These are the main reasons why we strongly advocate the adoption of a VA surveillance program based on CD-US.

[Ultrasound and color Doppler in nephrology. Physical and technical principles]. / L'ecografia e il color-Doppler in nefrologia. Le basi teoriche dell'ecografia.

Sonography is an imaging technique that generates tomographic images using ultrasound. The sound constitutes mechanical energy transmitted in a medium by pressure waves. Sound waves with frequencies greater than 20 kHz are called ultrasounds. Diagnostic ultrasounds use frequencies from 1 to 20 MHz. Ultrasound equipment is composed of a scanner, an image monitor, and different transducers that transform acoustic energy into electrical signals and electrical energy into acoustic energy (piezoelectric effect). The spatial resolution defines the minimum distance between two reflectors or echogenic regions that can be imaged as separate reflectors. The spatial resolution is mainly determined by the array design (linear, curved and sectorial) and by the operative system of the transducer. Modern ultrasound machines are very sophisticated medical devices that often support many transducers, imaging modes and display devices. The scan converter memory is the device in which images are formed and then presented to the monitor and to the hard copy devices.

[Ultrasound and color Doppler in nephrology. Acute kidney injury]. / L'ecografia e il color-Doppler in nefrologia. La malattia renale acuta.

At present, ultrasonography (US) is not able to define the type of renal damage and therefore cannot replace percutaneous renal biopsy in the diagnosis of acute kidney disease. It is, however, the most immediate and safest imaging technique for the evaluation of patients with acute kidney injury (AKI) in order to exclude urinary tract obstruction or chronic kidney disease and guide clinical decision-making. In prerenal AKI caused by cardiorenal syndrome type 1, US does not show specific signs. However, in these patients, pleuropulmonary US is the first-choice imaging technique to evaluate the congestion of subpleural interlobular septa and to identify and count lung comet tails. In cardiorenal syndrome type 2, US visualizes signs of systemic overload (right pleural effusion, liver stasis, overdistention and rigidity of the inferior vena cava and suprahepatic veins). In acute tubular necrosis (ATN), the most common type of AKI, gray-scale US is nonspecific and shows enlarged kidneys with hypoechoic pyramids due to medullary edema. The resistance index (RI) is a very useful marker to establish the severity of ATN and the required follow-up, and to evaluate functional recovery, since its reduction precedes the normalization of serum creatinine. US is the technique of choice in the diagnosis of obstructive nephropathy, where it is highly sensitive (>95%) but less specific (<70%). The primary objective of this review is to analyze the applications of US in the diagnosis of prerenal, renal and postrenal AKI.

[Ultrasound and color Doppler applications in chronic kidney disease]. / L'ecografia e il color-Doppler nella malattia renale cronica.

Chronic kidney disease (CKD) encompasses all clinical features and complications during the progression of various kidney conditions towards end-stage renal disease. These conditions include immune and inflammatory diseases such as primary and HCV-related glomerulonephritis; infectious diseases such as pyelonephritis with or without reflux and tuberculosis; vascular diseases such as chronic ischemic nephropathy; hereditary and congenital diseases such as polycystic disease and congenital cystic dysplasia; metabolic diseases including diabetes and hyperuricemia; and systemic diseases (collagen disease, vasculitis, myeloma). During the progression of CKD, ultrasound imaging can differentiate the nature of the renal damage in only 50-70% of cases. Infact, the end-stage kidney appears shrunken, reduced in volume (Ø <9 cm), unstructured, amorphous, with acquired cystic degeneration (small and multiple cysts involving the cortex and medulla) or nephrocalcinosis, but there are rare exceptions, such as polycystic kidney disease, diabetic nephropathy, and secondary inflammatory nephropathies. The main difficulties in the differential diagnosis are encountered in multifactorial CKD, which is commonly presented to the nephrologist at stage 4-5, when the kidney is shrunken, unstructured and amorphous. As in acute renal injury and despite the lack of sensitivity, ultrasonography is essential for assessing the progression of the renal damage and related complications, and for evaluating all conditions that increase the risk of CKD, such as lithiasis, recurrent urinary tract infections, vesicoureteral reflux, polycystic kidney disease and obstructive nephropathy. The timing and frequency of ultrasound scans in CKD patients should be evaluated case by case. In this review we will consider the morphofunctional features of the kidney in all nephropathies that may lead to progressive CKD.

[Ultrasound and color Doppler in nephrology. Technology and applications]. / L'ecografia e il color Doppler in nefrologia. Tecnologie e applicazioni ecografiche.

Advances in digital technology in the last decades have led to a fast development of ultrasound technology. Ultrasound information originating from stationary structures or red blood cells moving into the vessels can be visualized with different imaging modalities. Conventional B-mode sonography provides anatomical details based on acoustic impedance differences. Gray-scale sonography represents the structural echoes as brightness points. Based on the Doppler effect, vascular scattering can be represented as spectral wave velocity depending on time (velocity/time curve), or as dual-scale color mapping depending on the changes in average blood velocity. The flow-in is depicted in red and the flow-out in blue. The analysis of the vascular scattering enhanced by infusion of contrast agents is the basis of contrast-enhanced harmonic imaging. The perfusional pattern of tissues allows the differential diagnosis of expansive lesions. Tissue strain analysis provides a new dimension of diagnostic information. It is used in elastographic imaging to describe relative physical tissue stiffness properties. Tissue stiffness information is complementary to and independent of the acoustic impedance information provided by B-mode imaging as well as the vascular flow information provided by Doppler imaging. Adjacent tissue elements may appear identical using conventional B-mode or Doppler imaging. When stress (axial force) is applied to tissues, they show different degrees of deformation. Comparing the baseline and stress image information, each tissue element may be labeled by its relative stiffness. A lighter shade indicates relatively soft tissue (elastic), while a darker shade indicates relatively stiff tissue (non-elastic).

[Ultrasound and color Doppler imaging for kidney and urinary tract tumors]. / L'ecografia e il color Doppler in nefrologia. Tumori del rene e delle vie urinarie.

When a renal mass is suspected, conventional ultrasound and color Doppler imaging are often used for initial assessment. Ultrasound screening has many advantages over contrast-enhanced CT and MRI, such as accessibility, low costs, and no need for intravenous iodine contrast administration or ionizing radiation. Sonography is very helpful to distinguish cystic from solid lesions and to monitor the growth and structural pattern of cysts. Detection of small renal carcinoma of less than 3 cm in diameter is limited, however, and small tumors are detected by conventional ultrasound only in 67-79% of cases. In fact, small renal malignancies may have an echogenicity similar to the normal renal parenchyma. In these cases it is very hard to distinguish the tumor, particularly when there is no evident disarrangement of the normal renal contours and no extension into the central renal complex. Renal cell carcinoma can also be hypo- or hyperechoic and indistinguishable from renal adenoma/oncocytoma or angiomyolipomas, which are commonly described as hyperechoic masses. In other words, the pattern and ultrasound characteristics of renal masses often overlap between benign and malignant tumors. A diagnosis of a malignant cystic lesion requires evidence of multiple, thickened internal septa, calcifications, vascularity, and parietal nodularity. When a solid lesion does not show the typical appearance of a simple cyst (a round anechoic lesion with a smooth well-defined wall, without internal debris, and showing increased through-transmission), further evaluation with contrast-enhanced CT or MRI is necessary. Contrast-enhanced ultrasound (CEUS) improves the sensitivity for detection of small renal masses. Compared to CT, CEUS is able to better visualize the number of septa, the septum and wall thickness, the presence of a solid component, and enhancement in some cases, resulting in upgrading of the Bosniak classification and affecting treatment planning.

[Ultrasound and color Doppler applications in nephrology. The normal kidney: anatomy, vessels and congenital anomalies]. / L'ecografia e il color Doppler in nefrologia. Il rene normale: anatomia ecografica, vascolarizzazione e anomalie congenite.

Gray-scale ultrasound is the diagnostic technique of choice in patients with suspected or known renal disease. Knowledge of the normal and abnormal sonographic morphology of the kidney and urinary tract is essential for a successful diagnosis. Conventional sonography must always be complemented by Doppler sampling of the principal arterial and venous vessels. B-mode scanning is performed with the patient in supine, prone or side position. The kidney can be imaged by the anterior, lateral or posterior approach using coronal, transverse and oblique scanning planes. Morphological parameters that must be evaluated are the coronal diameter, the parenchymal thickness and echogenicity, the structure and state of the urinary tract, and the presence of congenital anomalies that may mimic a pseudomass. The main renal artery and the hilar-intraparenchymal branches of the arterial and venous vessels should be accurately evaluated using color Doppler. Measurement of intraparenchymal resistance indices (IP, IR) provides an indirect and quantitative parameter of the stiffness and eutrophic or dystrophic remodeling of the intrarenal microvasculature. These parameters differ depending on age, diabetic and hypertensive disease, chronic renal glomerular disease, and interstitial, vascular and obstructive nephropathy.

Use of ultrasound to assess the response to therapy for secondary hyperparathyroidism.

Secondary hyperparathyroidism (SHPT) is a common complication in patients with chronic kidney disease. In SHPT, the biology of parathyroid cells changes significantly toward diffuse nodular hyperplasia. Currently, diagnosis of SHPT is based on intact parathyroid hormone serum levels and parameters of mineral metabolism. The morphologic diagnosis of SHPT relies on high-resolution ultrasonography with color Doppler imaging. This report describes a maintenance hemodialysis patient with severe SHPT treated using conventional therapy (phosphate binders and oral/intravenous vitamin D or analogues) and the subsequent addition of a calcimimetic. The role of color Doppler ultrasonography in the diagnosis, clinical follow-up, and assessment of therapeutic response of SHPT is discussed. This case suggests that the availability of calcimimetics has changed the natural history of clinical SHPT and may change the therapeutic utility of parathyroidectomy. Use of color Doppler ultrasonography further supports these therapeutic advances, allowing evaluation of the morphologic and vascular changes in hyperplastic parathyroid glands and aiding clinical, pharmacologic, and surgical strategies.

Basics for performing a high-quality color Doppler sonography of the vascular access.

In the last years, the systematic use of ultrasound mapping of the upper limb vascular network before the arteriovenous fistula (AVF) implantation, access maturation, and clinical management of late complications is widespread and expanding. Therefore, a good knowledge of theoretical outlines, instrumentation, and operative settings is undoubtedly required for a thorough examination. In this review, the essential Doppler parameters, B-Mode setting, and Doppler applications are considered. Basic concepts on the Doppler shift equation, angle correction, settings on pulse repetition frequency, operative Doppler frequency, gain are reported to ensure adequate and correct sampling of blood flow velocity. A brief analysis of the Doppler inherent artefacts (as random noise, blooming, aliasing, and motion artefacts) and the adjustment setting to minimize or eliminate the confounding artefacts are also considered. Doppler aliasing occurs when the pulse repetition frequency is set too low. This artefact is particularly frequent in vascular access sampling due to the high velocities range registered in the fistula's different segments. Aliasing should be recognized because its correction is crucial to analyse the Doppler signals correctly. Recent advances in instrumentation are also considered about a potential purchase of a portable ultrasound machine or a top-of-line, high-end, or mid-range ultrasound system. Last, the pulse wave Doppler setting for vascular access B-Mode and Doppler assessment is summarized.

Ultrasound evaluation of access complications: Thrombosis, aneurysms, pseudoaneurysms and infections.

Arteriovenous fistula (AVF) complications are classified based on fistula outcomes. This review aims to update colour Doppler (CD) and pulse wave Doppler (PWD) roles in managing early and late complications of the native and prosthetic AVF. Vascular access (VA) failure occurs because inflow or outflow stenosis activates Wirchow's triad inducing thrombosis. Therefore, the diagnosis of the tributary artery and outgoing vein stenosis will be the first topic considered. Post-implantation complications occur from the inability to achieve AVF maturation and dialysis suitability due to inflow/outflow stenosis. Late stenosis is usually a sequence of early defects repaired to maintain patency. Less frequently, in the mature AVF or graft, complications are acquired 'de novo'. They derive either from incorrect management of vascular access (haematoma, pseudoaneurysm, prosthesis infection) or wall pathologies (aneurysm, myxoid valve degeneration, kinking, coiling, abnormal dilation from defects of elastic structures). High-resolution transducers (10-20 MHz) allow the characterization of the wall damage, haemodynamic dysfunctions, early and late complications even if phlebography remains the gold standard for the diagnosis for its sensitivity and specificity.

Long-term treatment with cinacalcet and conventional therapy reduces parathyroid hyperplasia in severe secondary hyperparathyroidism.

BACKGROUND: The effect of cinacalcet on the structural pattern of hyperplastic parathyroid glands was evaluated, using high-resolution colour Doppler (CD) sonography, in haemodialysis patients with severe, inadequately controlled, secondary hyperparathyroidism (sHPT). METHODS: Nine patients (6 males, 3 females; mean age +/- SD, 55.5 +/- 12.6 years) received cinacalcet, with adaptation of existing concomitant therapies. Biochemical parameters and the morphology and vascular pattern of hyperplastic parathyroid glands were measured at baseline and every 6 months thereafter, for a follow-up period of 24-30 months. RESULTS: At baseline, 28 hyperplastic glands were identified. Cinacalcet led to a reduction in glandular volume during the course of the study: 68% in glands with a baseline volume <500 mm(3) and 54% in glands with a baseline volume >or=500 mm(3). The mean volume +/- SD of glands <500 mm(3) changed significantly from the baseline (233 +/- 115 mm(3)) to the end of follow-up (102 +/- 132 mm(3), P = 0.007). Levels of mean serum phosphorus, calcium and calcium-phosphorus product decreased, but not significantly, whereas there were significant decreases in mean parathyroid hormone +/- SD levels (1196 +/- 381 pg/ml versus 256 +/- 160 pg/ml; P < 0.0001) and alkaline phosphatase +/- SD levels (428 +/- 294 versus 223 +/- 88 IU/l; P = 0.04), accompanied by an improvement in a subjective clinical score. CONCLUSIONS: Cinacalcet, in combination with conventional treatments, led to an improvement in biochemical and clinical parameters of sHPT and reduced glandular volume in patients with severe sHPT. Volume reduction was more evident in smaller glands. Longer term, larger, randomized clinical trials are needed to confirm these preliminary findings and to further define a more systematic approach in the treatment of sHPT.

The influence of preoperative psychological factors on weight loss after bariatric surgery: A preliminary report.

Aim of this study was to investigate relationship between preoperative psychological factors and % total weight loss after gastric bypass. 76 adult patients scheduled for bariatric surgery were preoperatively asked to complete anxiety and depression Hamilton scales and Toronto Alexithymia Scale. At 3- and 6-month follow-up, body weight was assessed. At 6-month follow-up, alexithymic patients showed a poorer % total weight loss compared with non-alexithymic patients ( p = .017), and moderately depressed patients showed a lower % total weight loss compared with non-depressed patients ( p = .011). Focused pre- and postoperative psychological support could be useful in bariatric patients in order to improve surgical outcome.

Ultrasound and color Doppler applications in chronic kidney disease.

Chronic kidney disease (CKD) includes all clinical features and complications during the progression of various kidney conditions towards end-stage renal disease (ESRD). These conditions include immune and inflammatory disease such as: primary and hepatitis C virus (HCV)-related glomerulonephritis; infectious disease such as pyelonephritis with or without reflux and tuberculosis; vascular disease such as chronic ischemic nephropathy; hereditary and congenital disease such as polycystic disease and congenital cystic dysplasia; metabolic disease including diabetes and hyperuricemia; and systemic disease (collagen disease, vasculitis, myeloma). During the progression of CKD, ultrasound imaging and color Doppler imaging (US-CDI) can differentiate the etiology of the renal damage in only 50-70% of cases. Indeed, the end-stage kidney appears shrunken, reduced in volume (Ø < 9 cm), unstructured, amorphous, and with acquired cystic degeneration (small and multiple cysts involving the cortex and medulla) or nephrocalcinosis, but there are rare exceptions, such as polycystic kidney disease, diabetic nephropathy, and secondary inflammatory nephropathies. The main difficulties in the differential diagnosis are encountered in multifactorial CKD, which is commonly presented to the nephrologist at stage 4-5, when the kidney is shrunken, unstructured and amorphous. As in acute renal injury and despite the lack of sensitivity, US-CDI is essential for assessing the progression of renal damage and related complications, and for evaluating all conditions that increase the risk of CKD, such as lithiasis, recurrent urinary tract infections, vesicoureteral reflux, polycystic kidney disease and obstructive nephropathy. The timing and frequency of ultrasound scans in CKD patients should be evaluated case by case. In this review, we will consider the morpho-functional features of the kidney in all nephropathies that may lead to progressive CKD.

[The Retroperitoneal space]. / Il Retroperitoneo questo sconosciuto.

We describe the case of a 45-year-old woman with a clinical history of breast cancer presenting with anuric renal failure, metabolic acidosis and bilateral grade 2-3 hydronephrosis. Following insertion of bilateral ureteral stents, urinary output was 5000 ml in the subsequent 24 hours with frankly bloody urine, after which anuria recurred. A new ultrasound examination showed hydronephrotic kidneys with properly positioned stents, a distended bladder free of clots and a hypo-anechoic, well-demarcated mass enveloping the aorta. With the echo color Doppler, injection of saline solution through a Foley catheter showed fluid flow similar to a ureteral jet within the bladder. Since the catheter balloon could not be sonographically visualized in the bladder we decided to re-examine this organ. Scans over what we thought was the bladder detected the balloon in a depleted bladder and fluid underlying it. CT urography revealed bilateral hydronephrosis secondary to a reperitoneal fibrous plaque surrounding the ureters and extending to the pelvic floor that had produced an encapsulated fluid collection. The clinical and imaging findings were strongly suggestive of acute obstructive renal failure secondary to retroperitoneal fibrosis. The retroperitoneal fluid collection, which had been mistaken for the bladder, may be due to a hematoma, aurinoma, an inflammatory process or a lymphocele.

Ultrasound findings of BK polyomavirus-associated nephropathy in renal transplant patients.

BK polyomavirus (BKV) is an emerging pathogen in immunocompromised patients. BKV infection occurs in 1-9 % of renal transplants and causes chronic nephropathy or graft loss. Diagnosis of BKV-associated nephropathy (BKVAN) is based on detection of viruria then viremia and at least a tubule-interstitial nephritis at renal biopsy. This paper describes the ultrasound and color Doppler (US-CD) features of BKVAN. Seventeen patients affected by BKVAN were studied using a linear bandwidth 7-12 MHz probe. Ultrasound showed a widespread streak-like pattern with alternating normal echoic and hypoechoic streaks with irregular edges from the papilla to the cortex. Renal biopsy performed in hypoechoic areas highlighted the typical viral inclusions in tubular epithelial cells. Our experience suggests a possible role for US-CD in the non-invasive diagnosis of BKVAN when combined with blood and urine screening tests. US-CD must be performed with a high-frequency linear probe to highlight the streak-like pattern of the renal parenchyma.

Clinical Scenarios in Chronic Kidney Disease: Parenchymal Chronic Renal Diseases - Part 1.

In diabetes, kidneys' morphological changes are non-specific at ultrasound (US) and they vary according to disease stage. In the earlier stages, kidneys are enlarged and diffusely hypoechoic due to hyperfiltration. Kidneys size decreases only in advanced stages whereas renal cortical echogenicity progressively increases due to glomerulosclerosis. Nephromegaly, as well as discrepancy between size and renal function, are typical features of diabetic nephropathy either in early or in advanced stages of the disease. Resistive indexes progressively increase together with serum creatinine levels and macro/microcirculation damage. Chronic glomerulonephritis (CGN) is the third leading cause of chronic kidney disease and it represents the clinical evolution of a variety of primary or secondary glomerular diseases. Kidneys in CGN are gradually reduced in volume, but remain symmetric, easily recognizable in renal space until the disease's later stages.

Clinical Scenarios in Chronic Kidney Disease: Cystic Renal Diseases.

Cysts are frequently found in chronic kidney disease (CKD) and they have a different prognostic significance depending on the clinical context. Simple solitary parenchymal cysts and peripelvic cysts are very common and they have no clinical significance. At US, simple cyst appears as a round anechoic pouch with regular and thin profiles. On the other hand, hereditary polycystic disease is a frequent cause of CKD in children and adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are the best known cystic hereditary diseases. ADPKD and ARPKD show a diffused cystic degeneration with cysts of different diameters derived from tubular epithelium. Medullary cystic disease may be associated with tubular defects, acidosis and lithiasis and can lead to CKD. Acquired cystic kidney disease, finally, is secondary to progressive structural end-stage kidney remodelling and may be associated with renal cell carcinoma.

Clinical Scenarios in Chronic Kidney Disease: Kidneys' Structural Changes in End-Stage Renal Disease.

Acquired cystic kidney disease (ACKD) and renal cell carcinoma (RCC) are the most important manifestations of end-stage kidneys' structural changes. ACKD is caused by kidney damage or scarring and it is characterized by the presence of small, multiple cortical and medullary cysts filled with a fluid similar to preurine. ACKD prevalence varies according to predialysis and dialysis age and its pathogenesis is unknown, although it is stated that progressive destruction of renal tissue induces hypertrophy/compensatory hyperplasia of residual nephrons and may trigger the degenerative process. ACKD is almost asymptomatic, but it can lead to several complications (bleeding, rupture, infections, RCC). Ultrasound (US) is the first level imaging technique in ACKD, because of its sensitivity and reliability. The most serious complication of ACKD is RCC, which is stimulated by the same growth factors and proto-oncogenes that lead to the genesis of cysts. Two different histological types of RCC have been identified: (1) RCC associated with ACKD and (2) papillary renal clear cell carcinoma. Tumors in end-stage kidneys are mainly small, multifocal and bilateral, with a papillary structure and a low degree of malignancy. At US, RCC appears as a small inhomogeneous nodule (<3 cm), clearly outlined from the renal profile and hypoechoic if compared with sclerotic parenchyma. In some cases, tumor appears as a homogeneous and hyperechoic multifocal mass. The most specific US sign of a small tumor in end-stage kidney is the important arterial vascularization, in contrast with renal parenchymal vascular sclerosis.