interpolar region of kidney anatomy

Normal magnetic resonance imaging appearance of the kidneys. Learning anatomy is a massive undertaking, and we're here to help you pass with flying colours. Calcifications and renal calculi are notoriously poorly demonstrated with MRI. Fetal lobulation is best differentiated from renal scars during the corticomedullary phase of enhancement on computed tomography (CT) or magnetic resonance imaging (MRI) because cortex can be followed into the indentation that occurs between calyces (Fig. Arterial stenosis was confirmed by magnetic resonance angiography. more lateral and anterior than the superior poles. Because the fascia of the retroperitoneum prevents significant extravasation, the incision usually heals to form a larger lumen. Coronal maximum intensity projection image from a contrast-enhanced computed tomographic scan demonstrates a dilated and tortuous lumbar veins joining the left renal vein. The opposite situation is possible too, if the kidneys excrete too many hydrogen ions, the pH of blood becomes too alkaline, and leads to a state called alkalosis. 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. Cells in our body constantly produce hydrogen ions. Ultrasound is usually used in the initial evaluation of the patient with newly diagnosed renal failure. 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. The cortex of a normal kidney is usually less echogenic than the adjacent normal liver. A, Steady-state free precession, (B) T2-weighted with fat saturation, (C) T1-weighted, (D) T1-weighted with fat saturation, (E) postcontrast corticomedullary phase, and (F) postcontrast nephrographic phase. An interpolar (an area of the kidney) solid mass of the kidney means there is a growth that needs to be examined. Each end of the kidney is commonly called a. Annotated three-dimensional volume rendering of the left kidney acquired using a combined nephrographic phase and excretory phase during computed tomographic urography demonstrates regional anatomy of the kidney. Because an extrarenal pelvis is not confined by the renal parenchyma, there is a tendency for it to expand. Since they are located deep retroperitoneally, the easiest way to examine them is from the patients back. 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. The anterior surface faces towards the anterior abdominal wall, whereas the posterior surface is facing the posterior abdominal wall. Hydronephrosis is important to detect, because obstructive uropathy is often reversible if identified early. The left kidney (not shown) had a similar appearance. Axial images of the left kidney from a three-phase renal computed tomographic scan demonstrate improved conspicuity of low-attenuation lesions of the renal medulla during the nephrographic phase. The small portion of the lumen surrounding the papilla is called the calyx. Ultrasound performed for acute renal failure demonstrates bilateral hydronephrosis caused by a bladder tumor. The portion of the kidney between the poles is called the interpolar region and contains the renal hilum (Fig. 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. Extraaortic origin of the renal arteries and accessory renal arteries are common. The pyramids are separated by extensions of the cortex called the renal columns. General symptoms of kidney problems include: blood in your urine . Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. Hypotension is a stimulus for the kidneys to increase the retention of fluid and thus increase blood pressure. 18-19). A. Junctional cortical line seen on a long-axis ultrasound image of the right kidney. BOX 18-2 Crossing Vessels in Ureteropelvic Junction Obstruction. A, A low-attenuation lesion is difficult to identify during the corticomedullary phase. This article will discuss the anatomy and major functions of the kidney. Because the interlobular arteries form an arch overlying the pyramid, they are called the arcuate arteries. 18-3). When abnormal echogenicity is detected, it is important to note whether it is unilateral or bilateral. 18-14). 18-19). B, The lesion becomes more conspicuous during the nephrographic phase. AMLs can bleed and while not cancerous are still taken very seriously. Figure 25.1.2 Left Kidney. Horseshoe kidneys result from midline fusion of the kidneys, typically at the level of the origin of the inferior mesenteric artery. Other malfunctions of the kidney are presented through acute kidney failure, a serious and urgent medical condition. 18-21). Look carefully for accessory arteries at upper and lower poles (Fig. Anterior components of circumaortic vein can be small. Despite different methods of accumulation, each is sequestered by the renal cortex, providing an opportunity to quantify the volume of renal parenchymal tissue in each kidney. "Angio" indicates blood vessels, "myo" indicates muscle, and "lipoma" indicates fat. a bifid renal pelvis, ultimately drained by a common ureter. The isthmus connecting the kidneys is variable, ranging from normal renal cortex to a thin fibrous band. CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. A, Axial image from contrast-enhanced computed tomography (CT) demonstrates an accessory right renal artery coursing anterior to the IVC. Fever. 18-7). Eliminating toxic metabolites through urine, regulation of blood homeostasis and blood pressure, production of some hormones, Positioned retroperitoneally, consists of the cortex and medulla, empties urine into the ureter (which carries urine to the urinary bladder), Renal artery (branch of the abdominal aorta), Renal vein (drains to the inferior vena cava), Third kidney, horseshoe kidney, kidney agenesis, kidney stones, acute kidney failure, Regulates the amount of fluid in the body by increasing or decreasing the urine production, Maintain the pH of blood at 7.4 by decreasing or increasing the excretion of hydrogen ions, Medial part of the lower half of superior pole, Lateral part of the lower half of superior pole, Lateral part of inferior half of anterior surface, Medial part of inferior half of anterior surface, The perinephric fat (perirenal fat capsule). Renal scintigraphy can be performed with a variety of agents to provide assessment of either function or structure of the kidneys. development and contrast excretion parallel those seen on contrast-enhanced CT with one notable exception (Fig. Surgery was successful and the surgeon confirmed the anatomic survey was correct. 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). Anatomy of the Kidney and Ureter Parenchyma Cortex Medulla Perirenal fat Capsule Ureter The presence or absence of intravenous contrast media, as well as the phase of contrast enhancement, are key factors that determine the appearance of the renal parenchyma on CT (Table 18-3). All rights reserved. 18-23). Figure 18-2 Annotated axial image of the right kidney from a contrast-enhanced computed tomographic scan demonstrates hilar anatomy of the kidney. Maintaining kidney health. chronic obstruction, or severe or repeated urinary infections. Although this dilatation of the renal pelvis may occasionally mimic hydronephrosis, delicate and sharply defined calyces and thin infundibula can be used to differentiate an extrarenal pelvis from obstruction. Diabetes, hypertension, acute tubular necrosis, Increased echogenicity has high association with parenchymal disease, Acute tubular necrosis usually results in an increased RI, whereas prerenal causes usually do not have an increased RI; postrenal causes often increase the RI, but hydronephrosis should be present in those cases, If present, suspect neurogenic bladder or outlet obstruction, Often severe aortic disease or fibromuscular dysplasia. 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. Unenhanced MRI can also be used to diagnose obstruction and identify the source (Fig. Always include unenhanced computed tomographic images to look for renal stones. The main function of the kidney is to eliminate excess bodily fluid, salts and byproducts of metabolism this makes kidneys key in the regulation of acid-base balance, blood pressure, and many other homeostatic parameters. For most people, obstruction of a single ureter does not induce renal failure. If a kidney stone becomes lodged in the ureters, it may block the flow of urine and cause the kidney to swell and the ureter to spasm, which can be very painful. Table 18-7 lists causes of unilateral smooth renal atrophy. Each kidney should always be evaluated in long axis (coronal, sagittal, or both, depending on sonographic window) and axial to the kidney. Chronic obstruction, however, results in damage to the papilla, evident in the clubbed calyx of papillary necrosis (Fig. If the renal pelvis extends out of the renal sinus, it is considered to be an extrarenal pelvis (Fig. 18-1). Note number of veins by inspecting inferior vena cava along entire length of kidney. However, sometimes ureteroscopy is required to confirm the diagnosis in patients with hematuria. 2023 Approximately 1 year before presentation, the patient experienced a similar episode of right flank pain that prompted an unenhanced CT examination of the abdomen and pelvis at an outside institution. . The kidneys are innervated by the renal plexus. This is called the nutcracker phenomenon. Curated learning paths created by our anatomy experts, 1000s of high quality anatomy illustrations and articles. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. When hydronephrosis is absent, the causative factor for acute renal failure is almost certainly prerenal or renal. The left testicular vein must ascend higher and it drains to the left renal vein at a right angle, unlike the right testicular vein which joins the inferior vena cava directly. C, More severe hydronephrosis results in more pronounced shortening of the papilla. The renal veins empty to the inferior vena cava, so the right vein is shorter because the inferior vena cava runs closer to the right kidney. Because production of creatinine is affected by sex, age, muscle mass, protein intake, and liver function, the serum creatinine can be an inaccurate predictor of renal function, particularly in those at the extremes of age and body weight. Each pyramid creates urine and terminates into a renal papilla. Internal Anatomy. Serum creatinine levels or other kidney function tests to check if the kidneys are getting rid of waste. Sagittal ultrasound image of the right kidney demonstrates increased size and echogenicity of the kidney, findings typical of human immunodeficiency virus nephropathy. Global insult to one kidney may result in unilateral atrophy that is uniform and smooth. The medulla is the inner region of the parenchyma of the kidney. In most kidneys, the renal hilum faces more anteromedial in the upper half of the kidney and more directly medial in the lower half. The kidneys are positioned retroperitoneally, meaning that they are not wrapped with the peritoneal layers the way most abdominal organs are, but rather are placed behind it. This is just a peek into the kidney physiology. The anterior surface of the left kidney, has the following anatomical relations: The posterior surfaces of both kidneys are related to certain neurovascular structures and muscles: You can easily remember these with the mnemonic: 1-2-3-4 All Boys Need Muscle. Urine that is concentrated in the renal papilla is subsequently excreted into a lumen lined with transitional epithelium. The kidneys are highly vascular (contain a lot of blood vessels) and are divided into three main regions: the renal cortex (outer region which contains about 1.25 million renal tubules), renal medulla (middle region which acts as a collecting chamber), and renal pelvis (inner region which receives urine through the major calyces). The adrenal cortex directly influences renal function through the production of the hormone aldosterone to stimulate sodium reabsorption. This kidney measured 14 cm in length. The kidneys are paired retroperitoneal structures that are normally located between the transverse processes of T12-L3 vertebrae, with the left kidney typically somewhat more superior in position than the right. Axial maximum intensity projection image from the arterial phase of a contrast-enhanced computed tomographic scan from a prospective renal donor demonstrates early prehilar branching of the left renal artery. In this region, the anterior and posterior hilar lip is identified (Fig. Read More Created for people with ongoing healthcare needs but benefits everyone. February 12, 2018 - 2:17pm 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. 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. impression is preserved. This can cause varicocele of the left testicle because gravity works against the column of the blood in the left testicular vein. Imaging must provide detailed images of the renal parenchyma and a survey of arterial, venous, and ureteral anatomy. Kidney stones are most often treated by ultrasound shock therapy, during which high-frequency radio waves break the stone into smaller pieces that can be passed naturally into the urine. Coronal computed tomographic image in the corticomedullary phase shows normal corticomedullary differentiation along the lobulated contour, consistent with fetal lobulation. Table 18-1 Imaging the Living Renal Donor. Association between Renal Cortical Echogenicity and Renal Parenchymal Disease. Poorly functioning kidneys with little residual parenchymal volume may be removed because preservation offers opportunities for future complications (infection, hypertension) without contributing significantly to renal function. The kidneys serve important . Kidneys are located just below your ribcage and behind your belly. Thus, any upward trend in the serum creatinine value should be viewed with concern when considering the administration of potentially nephrotoxic or renally excreted intravenous contrast media. Illustration demonstrating the relation between the renal papilla and calyx. At the Brady Urological Institute, we believe in the adage, "An ounce of prevention is worth a pound of cure," so we place great emphasis on a thorough metabolic evaluation, so that therapies can be appropriately directed towards reducing the risk of recurrent stone disease. Chronic glomerulonephritis usually causes bilateral increased renal echogenicity with smooth atrophy, whereas renal artery stenosis usually causes a similar but unilateral appearance (Fig. Depending on where the cyst is located, it can affect how the kidney works. T2-weighted maximum intensity projection image from a magnetic resonance urogram performed to evaluate urinary obstruction identified in a patient with an obstructing soft tissue mass in the pelvis on unenhanced computed tomography (CT). Now lets pay attention to the borders of the kidneys. The goal of imaging patients with renal failure is to identify a correctable cause in an effort to recover or preserve renal function. Furthermore, since the left renal vein passes between the superior mesenteric artery and the abdominal aorta, an enlargement of the superior mesenteric artery can compress the left renalvein and cause an obstruction of drainage from all three structures that use the left renal vein for drainage (left suprarenal gland, left kidney, and left testicle). Typically, one kidney sits on either side of your spine. 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To look for renal stones to assess renal function with a variety of agents to provide assessment of function...

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