Renal size and cortical thickness can be assessed in a manner similar to ultrasound. Some forms of congenital UPJ obstruction are now treated with transureteroscopic endopyelotomy in which an incision is made from within the ureter using a ureteroscope. urinary system quizzes and labeled diagrams. 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. This can cause varicocele of the left testicle because gravity works against the column of the blood in the left testicular vein. However, T1-weighted images provide good corticomedullary differentiation. This method is the standard in evaluation of UPJ obstruction and often is used for other types of chronic obstruction. Each segmental branch of the renal artery divides into multiple interlobar arteries that course along the periphery of the medullary pyramids and causes small interlobular branches (Fig. 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. Axial image from unenhanced computed tomography of the kidneys performed 2 days after an angiographic procedure demonstrates stasis of contrast in the renal cortex, resulting in a persistent corticomedullary phase of enhancement. Table 18-1 provides a quick guide itemizing key imaging findings in the potential renal donor. In this way, the consistency of blood is preserved and no important substances are lost. This article will discuss the anatomy and major functions of the kidney. The patient had right flank pain but had a solitary calcification in the left pelvis on plain radiograph (not shown). More tenuous vascular supply to the renal medulla makes it more susceptible to ischemia. Calcifications and renal calculi are notoriously poorly demonstrated with MRI. A, Tips of the fornices are sharply defined. Ultrasound can often identify the cause in cases of bilateral obstruction (Fig. It protects your kidneys from injury, increases their stability and connects your kidneys to surrounding tissues. Read More Created for people with ongoing healthcare needs but benefits everyone. Chronic glomerulonephritis usually causes bilateral increased renal echogenicity with smooth atrophy, whereas renal artery stenosis usually causes a similar but unilateral appearance (Fig. This phenomenon is due to T2-shortening and susceptibility (T2*) effects caused by concentrated gadolinium, and can potentially obscure filling defects and urothelial lesions. C, More severe hydronephrosis results in more pronounced shortening of the papilla. Jana Vaskovi MD Accurate preoperative imaging protects the healthy donor from complications related to unanticipated variant anatomy. Figure 18-17 Coronal maximum intensity projection image from a contrast-enhanced computed tomographic scan demonstrates a dilated and tortuous lumbar veins joining the left renal vein. Renal cysts are sacs of fluid that form in the kidneys. The apex of the pyramid projects medially toward the renal sinus. The anteromedial, aspect of the interpolar region is interrupted by the renal hilum to make a C shape. Each pyramid creates urine and terminates into a renal papilla. Other symptoms can include abnormal urine color, blood in your urine, fever, chills, nausea, and vomiting. Unilateral renal agenesis occurs in approximately 1 in 1000 individuals with minimal impact on health, although it is sometimes associated with other congenital anomalies of the genitourinary tract and musculoskeletal system. 18-11). The goal of imaging patients with renal failure is to identify a correctable cause in an effort to recover or preserve renal function. The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. Look carefully for accessory arteries at upper and lower poles (Fig. Chronic glomerulonephritis usually causes bilateral increased renal echogenicity with smooth atrophy, whereas renal artery stenosis usually causes a similar but unilateral appearance (Fig. Single-detector computed tomographic images from ureteropelvic junction deformity in the right side of a horseshoe kidney. Ultrasound It can be seen as a triangular echogenic cortical defect, frequently seen in upper lobe parenchyma. When abnormal echogenicity is detected, it is important to note whether it is unilateral or bilateral. Figure 18-8 Junctional cortical line seen on a long-axis ultrasound image of the right kidney. 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. One of the most commonly used (and least complicated) equations is shown in Box 18-1. Ultrasound permits real-time optimization of imaging relative to the axis of each kidney. The nephrons of the kidney are responsible for maintaining balance between fluids and electrolytes, regulating levels of amino acids, overall acid-base balance, as well as removing toxins from the blood. Made. When simple kidney cysts do cause symptoms, they might include: Pain in the side between the ribs and hip, stomach or back. 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. Figure 18-1 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. B, Mild hydronephrosis results in rounding of the fornices with mild shortening of the papillary impression. 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. Note distance from origin to the first arterial division (Fig. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. AMLs can bleed and while not cancerous are still taken very seriously. Horseshoe kidneys result from midline fusion of the kidneys, typically at the level of the origin of the inferior mesenteric artery. Bone scan and chest x-ray to find out if the cancer has spread. A, Axial image from contrast-enhanced computed tomography (CT) demonstrates an accessory right renal artery coursing anterior to the IVC. Identify abnormal course of main or accessory right renal artery anterior rather than posterior to inferior vena cava (Fig. Kidneys have a special system for the excretion of hydrogen ions, and in that way consistently maintain the pH of blood at 7.4. Computed Tomographic Appearance of the Kidneys, Utility of Different Phases of Renal Contrast Enhancement. 2023 Localized means that the tumor has not spread out from where it first started. 18-5). Caliectasis doesn't cause any symptoms on its own. Table 18-1 Imaging the Living Renal Donor. February 12, 2018 - 2:17pm The causes of renal failure can be categorized as prerenal, renal, and postrenal (Table 18-4). 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. 18-21). It participates in vital processes such as regulation of blood osmolarity and pH, regulation of blood volume and blood pressure, production of hormones, and filtration of foreign substances. The lateral border is directed towards the periphery, while the medial border is the one directed towards the midline. Other methods include classical surgical removal of the stone, either through the ureter or by open surgery. It is important to note, however, that the appearance of hydronephrosis does not necessarily indicate urinary obstruction (see Hydronephrosis and Its Mimics section later in this chapter). Note number of veins by inspecting inferior vena cava along entire length of kidney. Extraaortic origin of the renal arteries and accessory renal arteries are common. Supernumerary kidneys are quite rare and have been associated with aortic coarctation, vaginal atresia, and urethral duplications. 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. But here is a neat little mnemonic to help. Anterior components of circumaortic vein can be small. 18-18). 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 information we provide is grounded on academic literature and peer-reviewed research. If the renal pelvis extends out of the renal sinus, it is considered to be an extrarenal pelvis (Fig. Differential diagnosis General imaging considerations include: renal cortical defect duplex kidney The muscular relations of the inferior half are easy to remember by dividing the kidney surface into three vertical stripes, where the medial stripe represents the impression of the psoas major muscle, the central stripe the quadratus lumborum, and the lateral stripe the transversus abdominis muscle. Thus, an AML is a tumor that contains these 3 components. The small portion of the lumen surrounding the papilla is called the. The interpolar region is the middle of the kidney. Retrograde urogram shows a calculus in the left ureter. RENAL ANATOMY Renal Parenchyma The kidneys can be divided into three main regions from cranial to caudal. 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. Look for duplication, large extrarenal pelvis. In this region, the anterior and posterior hilar lip is identified (Fig. The upper poles are normally oriented more medially and posteriorly than the lower poles. Sometimes, one or both kidneys fail to develop, which causes unilateral or bilateral renal agenesis. CT scan and MRI to help diagnose and stage kidney masses. Note that the left renal vein receives blood from the left suprarenal and left testicular veins. CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. The left kidney appeared unremarkable. The anteromedial aspect of the interpolar region is interrupted by the renal hilum to make a C shape. Use of MR contrast agents in renal failure poses a lower risk than iodinated contrast material for exacerbating renal failure, but there is evidence that gadolinium-based MR contrast media pose some risk for systemic complications (nephrogenic systemic fibrosis) and should be used with caution in patients with severe or acute renal insufficiency. While migrating superiorly, the kidneys rotate medially along their long axes and the inferior supplying mesonephric arteries degenerate. When echogenicity of the renal cortex equals that of the liver, renal function is abnormal in approximately 38% of cases. When abnormal echogenicity is detected, it is important to note whether it is unilateral or bilateral. The calcium or uric acid will precipitate and form stones. 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). The urinary system comprises the upper urinary tracts (kidneys and ureters), the urinary bladder, and the urethra. 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. Overview. The main parts of your kidney anatomy include: Kidney capsule (renal capsule) The renal capsule consists of three layers of connective tissue or fat that cover your kidneys. Each kidney has a single renal vein which conducts the blood out of the kidney and is positioned anterior to the artery. Figure 18-11 Three-dimensional volume rendering from contrast-enhanced multidetector computed tomography examination of the kidneys demonstrates typical orientation of a horseshoe kidney. This causes them to fire impulses which stimulate rhythmical contraction and relaxation, called peristalsis. But more often, kidney cysts are a type called simple kidney cysts. 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). Ultrasound It can be seen as a triangular echogenic cortical defect, frequently seen in upper lobe parenchyma. Around 40% of kidney cancers are localized renal masses. Computed Tomographic Evaluation for Renal Failure, Magnetic Resonance Evaluation for Renal Failure. An increased amount of hydrogen ions can acidify the blood and cause a state called acidosis. In most cases, unenhanced CT is performed when the duration and cause of renal failure are unknown because exposure to iodinated contrast media could impair recovery of renal function. Ultrasound is usually used in the initial evaluation of the patient with newly diagnosed renal failure. Diagnostic ultrasound uses sound wave technology to look at parts of your body, including: Brain Heart and blood vessels Breast Abdominal Organs Eyes Thyroid Skin and muscles Types of Ultrasound. Grounded on academic literature and research, validated by experts, and trusted by more than 2 million users. This refers to the forming of the stones within the system of calyces because of too much calcium or uric acid into the filtrate. When. 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