Caliectasis doesn't cause any symptoms on its own. Some tumors can be slow to grow while some can be aggressive. On the other hand, babies with bilateral agenesis cannot survive without an immediate kidney transplant. In other cases, both kidneys can be fused, usually at the inferior poles, which is a congenital state called the horseshoe kidney. People with unilateral agenesis often are unaware that they lack one kidney until an accidental discovery, since the one kidney that they have is able to functionally compensate for the other. Crossing Vessels in Ureteropelvic Junction Obstruction, Conventional surgery for congenital UPJ obstruction involves an open pyeloplasty, in which some tissue is removed from the wall of the saclike renal pelvis to form a more tapered, efficient, funnel-shaped renal pelvis. Because of this, the tubules are designed in a way that they reabsorb the necessary substances, (sodium, potassium, and amino acids as mentioned before) and carries them back to the blood; whereas they do not absorb but rather secrete unnecessary substances such as creatinine and drug metabolites for excretion from the body. Of course, if the situation is the other way around (less than 5 liters of blood), blood pressure is too low (hypotension). B, Transverse image of the bladder demonstrates a large bladder tumor in the region of the trigone. 18-25). When the renal cortex is more echogenic than the adjacent liver, there is a high correlation with renal disease, although sensitivity is relatively low, according to Platt and colleagues (Fig. Made. In most kidneys, the renal hilum faces more anteromedial in the upper half of the kidney and more directly medial in the lower half. Each end of the kidney is commonly called a pole. Typically, one kidney sits on either side of your spine. 18-7). Log In or, Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Estimated Creatinine Clearance and Glomerular Filtration Rate, Cockroft and Gault Equation for Calculating Estimated Creatinine Clearance, The Modification of Diet in Renal Disease (MDRD) is another method for estimating renal function that yields a value often called, The kidneys can be divided into three main regions from cranial to caudal. Around 40% of kidney cancers are localized renal masses. It is also permeable for the products of the metabolism, such are creatinine and drug metabolites. A junctional cortical line is a common septum of capsule typically seen on ultrasound as an echogenic line at the site of fusion between the superior pole and middle third of the kidney (Fig. So the pyramids represent the functional tissue that creates urine, whereas the calyces are the beginning of the ureter and transport the urine to it. Renal scintigraphy can be performed with a variety of agents to provide assessment of either function or structure of the kidneys. Ultrasound can often identify the cause in cases of bilateral obstruction (, Pelvic mass (cervical, rectal, uterine, prostate cancer). This phenomenon is due to T2-shortening and susceptibility (T2*) effects caused by concentrated gadolinium, and can potentially obscure filling defects and urothelial lesions. Now that weve mastered the borders, it will be easier to take a closer look at the anatomical relations that the kidneys share with other abdominal structures. Most serum creatinine is excreted in the urine; therefore, if renal function is compromised, levels of creatinine in the serum increase. Table 18-6 Causes of Bilateral Small Smooth Kidneys. If the renal pelvis extends out of the renal sinus, it is considered to be an. 18-25). The left kidney appeared unremarkable. It's not clear what causes simple kidney cysts. It protects your kidneys from injury, increases their stability and connects your kidneys to surrounding tissues. Most radiologists consider 10 to 12 cm to be an approximate reference range for renal length in adults, allowing for an additional 1 cm in either direction for patients at the extremes of height. On the superior aspect of each kidney is the adrenal gland. Figure 18-12 Axial sections of the right kidney from contrast-enhanced computed tomography demonstrate a bar of renal parenchyma separating renal hila in the superior and inferior poles, consistent with duplication. Increasing pressure within the lumen initially distends the fornices (acutely angled portions of the calyx along the sides of the papillae), whereas the central portion of the papillary impression is preserved. 3D printed model for a 53-year-old female presenting a 21 15 15 mm renal tumor located in the interpolar region of left kidney, treated by left partial nephrectomy. When echogenicity of the renal cortex equals that of the liver, renal function is abnormal in approximately 38% of cases. Look for duplication, large extrarenal pelvis. The corticomedullary phase is prolonged in the presence of ureteral or venous obstruction and can persist for days in cases of acute tubular necrosis (ATN; Fig. 18-1). As the lobules of metanephric blastema coalesce to form each kidney, they do not always result in a smooth, uniform band of cortex. Kenhub. Calculation of the estimated renal volume is considered by some to be the most accurate assessment of renal size available with ultrasound, although renal length alone is more commonly reported. The pyramids contain the functional units of the kidney, the nephrons, which filter blood in order to produce urine which then is transported through a system of the structures called calyces which then transport the urine to the ureter. (Courtesy of Karl T. Rew, MD) Introduction Synonyms Epidemiology The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. Normal parenchymal enhancement on CT or MRI allows definitive characterization. If the renal pelvis extends out of the renal sinus, it is considered to be an extrarenal pelvis (Fig. Thus, an AML is a tumor that contains these 3 components. Their shape resembles a bean, where we can describe the superior and inferior poles, as well as the major convexity pointed laterally, and the minor concavity pointed medially. A, Sagittal image of the left kidney demonstrates hydronephrosis and hydroureter. More tenuous vascular supply to the renal medulla makes it more susceptible to ischemia. Box 18-2 provides some tips regarding crossing vessels in UPJ obstruction. The causes of renal failure can be categorized as prerenal, renal, and postrenal (Table 18-4). The region where the renal pelvis joins the ureter is called the, If the renal pelvis is entirely within the confines of the renal sinus, it is considered intrarenal. For most people, obstruction of a single ureter does not induce renal failure. In clinical practice, it is probably best to categorize the renal cortex as hypoechoic, isoechoic, or hyperechoic compared with normal liver, and then state a correlative risk for associated renal parenchymal disease (. Created for people with ongoing healthcare needs but benefits everyone. There is no specific treatment for fused kidneys and the only option is to treat the pathologies that affect them during life. Serum creatinine levels or other kidney function tests to check if the kidneys are getting rid of waste. But here is a neat little mnemonic to help. Concerning lymphatic drainage, each kidney drains into the lateral aortic (lumbar) lymph nodes, which are placed around the origin of the renal artery. Overview. The most common indication for cortical scintigraphy is to evaluate kidneys that have been injured by vesicoureteral reflux, chronic obstruction, or severe or repeated urinary infections. After looking at the overview of the kidneys in situ, it may seemas they are cluttered with all abdominal organs. Figure 18-16 Coronal reformation from contrast-enhanced computed tomography performed for renal donation demonstrates a retroaortic left renal vein crossing the aorta well inferior to the level of the renal hila. When fused, the condition is described as crossed fused ectopia. Hydronephrosis is important to detect, because obstructive uropathy is often reversible if identified early. When the fine, weblike complex of ureteral arteries is recruited to contribute to collateral circulation, enlarged vessels are seen surrounding the proximal ureter, causing the classic ureteral notching seen on intravenous urogram (IVU). Figure 18-19 Sagittal ultrasound image of the right kidney demonstrates increased size and echogenicity of the kidney, findings typical of human immunodeficiency virus nephropathy. Extraaortic origin of the renal arteries and accessory renal arteries are common. Each kidney has a single renal vein which conducts the blood out of the kidney and is positioned anterior to the artery. Anatomical Position of the Kidneys Kidney Structure Table 18-2 Association between Renal Cortical Echogenicity and Renal Parenchymal Disease. In fact, evaluation of the renal collecting system during the excretory phase often requires window and level settings approaching those used for evaluating the osseous structures (Fig. On the other hand, the products of cellular metabolism and drug metabolites are eliminated from the blood which prevents their depositing in the body and potential toxicity. Note origin of inferior accessories near inferior poles on each side. In adults, the normal kidney is 10-14 cm long in males and 9-13 cm long in females, 3-5 cm wide, 3 cm in antero-posterior thickness and weighs 150-260 g. The left kidney is usually slightly larger than the right. 18-18). The kidneys can be divided into three main regions from cranial to caudal. Parasympathetic innervation enhances the peristalsis while sympathetic innervation inhibits it. The renal cortex and medulla both have high signal intensity on T2-weighted images resulting in poor corticomedullary differentiation. CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. The isthmus connecting the kidneys is variable, ranging from normal renal cortex to a thin fibrous band. CT and MR findings of renal artery stenosis parallel classic findings described on intravenous pyelogram, including one atrophic kidney with delayed nephrogram and excretion that can progress to a persistent nephrogram with hyperconcentrated excreted contrast media (Fig. Living renal donor allografts account for more than half of the transplanted kidneys in the United States. The medial border of the kidney contains a very important landmark called the hilum of the kidney, which is the entry and exit point for the kidney vessels and ureter. The dynamics of obstruction and quantification of relative renal function between the two kidneys may be important considerations in two general circumstances: (1) it is unclear whether obstruction is severe enough to warrant surgical intervention; or (2) significant parenchymal atrophy exists, and the relative merits of repair and nephrectomy are being compared. Axial image of the left kidney from a contrast-enhanced computed tomographic scan demonstrates an extrarenal pelvis. The highest portion of the superior pole is covered with the, The superior one-half of the anterior surface is in contact with the layer of, At exactly the center of the anterior surface, imagine a horizontal stripe that extends from the medial concavity toward the center of the lateral convexity that is the area of the kidney that is directly touched by the retroperitoneal posterior wall of the, The lateral part of the inferior pole is directly contacted with the, The rest of the inferior pole is associated with the peritoneum of the, Just like the right kidney, the highest part of the superior pole of the left is also covered with the, The inferior portion of the superior pole contacts with the peritoneum of the, Just inferior to the stomach and spleen impression, is where the left kidney directly contacts, The lateral part of the inferior half of the anterior surface is directly associated with the left colic flexure (also known as the splenic flexure) and, The medial part of the inferior half and the inferior pole are contacted by the peritoneum of the, Kidney structure (overview) - Mohammed Albakkar, Kidneys in situ (overview) - Johannes Reiss, Internal anatomy of the kidney (overview) - Mohammed Albakkar, Arteries of the kidney (overview) - Abdulmalek Albakkar, Kidneys in a cadaver - Prof. Carlos Surez-Quian. Frequent urination (having to go the bathroom often). Note number of veins by inspecting inferior vena cava along entire length of kidney. Many clinical laboratories now provide computer-generated calculations of estimated creatinine clearance or eGFR using patient data in the medical information system. Kidney cysts can occur with disorders that may impair kidney function. Internal Anatomy. Differential diagnosis General imaging considerations include: renal cortical defect duplex kidney The most common cause is renal artery stenosis (see Fig. urinary system quizzes and labeled diagrams. The phases of nephrogram. The interpolar region is the middle of the kidney. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. In this way, the consistency of blood is preserved and no important substances are lost. A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal medulla (Figure 25.1.2). The segmental arteries then branch into the interlobar arteries, which further branch into the arcuate arteries. Comparative views of the CT scan ( a axial, b coronal, and c sagittal planes) and corresponding views of the physical model ( d superior view, e median view, and f median view). Three-dimensional volume rendering from contrast-enhanced multidetector computed tomography examination of the kidneys demonstrates typical orientation of a horseshoe kidney. 18-3). This illustrates the amount of reserve function that must be compromised before renal injury can be detected with a serum creatinine level. With ongoing healthcare needs but benefits everyone of reserve function that must be compromised before renal can. All abdominal organs reserve function that must be compromised before renal injury can be performed with serum! 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