Radiological examination of the urinary tract and retro-peritoneal space.

Radiological examination Radiological examination of the urinary tract and of the urinary tract and retro-peritoneal space.retro-peritoneal space.

DEPARTMENT OF ONCOLOGY DEPARTMENT OF ONCOLOGY AND RADIOLOGYAND RADIOLOGY

PREPARED BY I.M.LESKIVPREPARED BY I.M.LESKIV

RENAL STRUCTURE RENAL STRUCTURE AND FUNCTIONAND FUNCTION

The kidneys control the volume, composition, The kidneys control the volume, composition, and pressure of body fluids by regulating the and pressure of body fluids by regulating the excretion of water and solutes. They also excretion of water and solutes. They also influence red cell production and blood influence red cell production and blood pressure by hormonal mechanisms. Urine is pressure by hormonal mechanisms. Urine is formed in the kidneys as an aqueous solution formed in the kidneys as an aqueous solution containing metabolic waste products, foreign containing metabolic waste products, foreign substances, and water-soluble constituents substances, and water-soluble constituents of the body in quantities depending upon of the body in quantities depending upon homeostatic needs.homeostatic needs.

AnatomyAnatomy

The kidneys are bilateral, retroperitoneal structures, each consisting of an The kidneys are bilateral, retroperitoneal structures, each consisting of an outer cortex and an inner medulla. The medulla is arranged into several cone-outer cortex and an inner medulla. The medulla is arranged into several cone-shaped or; pyramidal projections separated from each other by sections of shaped or; pyramidal projections separated from each other by sections of cortex called renal columns. The bases of the pyramids face the cortex of the cortex called renal columns. The bases of the pyramids face the cortex of the kidney while the apices (papillae) point toward the hilus and project into the kidney while the apices (papillae) point toward the hilus and project into the renal pelvis. The; cortex contains glomeruli and tubules; the medulla, tubules renal pelvis. The; cortex contains glomeruli and tubules; the medulla, tubules only.only.

The kidneys possess numerous blood vessels and because of their low The kidneys possess numerous blood vessels and because of their low vascular resistance receive approximately 1200 ml of blood or 25% of the vascular resistance receive approximately 1200 ml of blood or 25% of the cardiac output each minute.cardiac output each minute.

The major resistance to blood flow occurs in the glomerular capillary bed and The major resistance to blood flow occurs in the glomerular capillary bed and is produced by a relatively high resistance in the efferent arterioles. However, is produced by a relatively high resistance in the efferent arterioles. However, changes in renal arterial pressure produce proportional variations in the changes in renal arterial pressure produce proportional variations in the afferent arteriolar resistance, which tends to preserve a constant renal blood afferent arteriolar resistance, which tends to preserve a constant renal blood flow (RBF) and glomerular capillary pressure; i.e., autoregulation. In addition flow (RBF) and glomerular capillary pressure; i.e., autoregulation. In addition to autoregulatioaj the renal circulation is controlled by extrinsic factors such to autoregulatioaj the renal circulation is controlled by extrinsic factors such as neurogenic (sympa thetic) and hormonal (epinephrine, norepinephrine, and as neurogenic (sympa thetic) and hormonal (epinephrine, norepinephrine, and angiotensin) regulators.angiotensin) regulators. I I

Sagittal section of the kidney. The upper half depicts the overall Sagittal section of the kidney. The upper half depicts the overall gross anatomic arrangement The lower half demonstrates the gross anatomic arrangement The lower half demonstrates the arterial supply.arterial supply.

The NephronThe Nephron The basic functional unit of the The basic functional unit of the

kidney is the nephron, a long kidney is the nephron, a long tubular structure made up tubular structure made up of of successive segments of diverse successive segments of diverse structure and transport structure and transport functions. It includes (1) a renal functions. It includes (1) a renal corpuscle (Bowman's capsule corpuscle (Bowman's capsule and the glomerulus, a tuft of and the glomerulus, a tuft of capillaries), (2) a proximal capillaries), (2) a proximal tubule (convoluted and straight tubule (convoluted and straight portion), (3) a hairpin loop portion), (3) a hairpin loop (Henle's loop), (4) a distal (Henle's loop), (4) a distal tubule (straight portion, macula tubule (straight portion, macula densa, and convo luted portion), densa, and convo luted portion), and (5) a collecting duct system. and (5) a collecting duct system. There are approximately one There are approximately one million nephrons in each human million nephrons in each human kidney; 85% are cortical kidney; 85% are cortical nephrons with short loops of nephrons with short loops of Henle, and 15% are Henle, and 15% are juxtamedullary nephrons with juxtamedullary nephrons with glomeruli near the cortical glomeruli near the cortical medullary junction and with medullary junction and with long, thin, looping segments long, thin, looping segments

Glomerular Glomerular FiltrationFiltrationThe glomerulus acts as an The glomerulus acts as an ultrafilter, allowing passage ultrafilter, allowing passage of water, electrolytes, and of water, electrolytes, and small organic molecules small organic molecules such as glucose, but not such as glucose, but not blood cells and large protein blood cells and large protein molecules. The ultrafiltrate molecules. The ultrafiltrate produced by the glomeruli produced by the glomeruli of both kidneys amounts to of both kidneys amounts to about 70 ml/min/sq m or about 70 ml/min/sq m or 150 L/day/sq m; this rate is 150 L/day/sq m; this rate is termed the glomerular termed the glomerular filtration rate (GFR). About filtration rate (GFR). About 99% of the glomerular 99% of the glomerular filtrate is resorbed during filtrate is resorbed during pas sage through the renal pas sage through the renal tubules, with most of the tubules, with most of the resorption taking place in resorption taking place in the proximal tubules.the proximal tubules.

The Concept of "Clearance" and the The Concept of "Clearance" and the Measurement of GFRMeasurement of GFR

A principal function of the kidney is to remove A principal function of the kidney is to remove or "clear" various solutes from the blood or "clear" various solutes from the blood which are not essential to the body, and to which are not essential to the body, and to conserve those that the body requires. A solute conserve those that the body requires. A solute is never totally removed from the blood in any is never totally removed from the blood in any one passage through the kidneys; rather, a one passage through the kidneys; rather, a portion is removed during each sweep of the portion is removed during each sweep of the blood through the renal system. Clearance blood through the renal system. Clearance may be defined as may be defined as the volume of plasma which the volume of plasma which is completely cleared of a solute in a unit of is completely cleared of a solute in a unit of time time and is usually expressed in ml/min.and is usually expressed in ml/min. Stated Stated another way, another way, the renal clearance of a the renal clearance of a substance represents the volume of blood that substance represents the volume of blood that would have to pass through the nephrons would have to pass through the nephrons within a given time period to provide the within a given time period to provide the amount of that substance in the urine. amount of that substance in the urine. Substances which are rapidly eliminated have Substances which are rapidly eliminated have a high clearance; those eliminated slowly, a a high clearance; those eliminated slowly, a low clearance.low clearance.

Radiological Radiological examination of the examination of the urinary tracturinary tract The four basic examinations of the urinary tract are intravenous The four basic examinations of the urinary tract are intravenous

urography (IVU), computed tomography (CT), ultrasound and urography (IVU), computed tomography (CT), ultrasound and radionuclide examinations. Magnetic resonance imaging (MRI), radionuclide examinations. Magnetic resonance imaging (MRI), arteriography and studies requiring catheterization or direct puncture arteriography and studies requiring catheterization or direct puncture of the collecting systems are limited to highly selected patients.of the collecting systems are limited to highly selected patients.

The IVU provides both functional and anatomical information. CT, The IVU provides both functional and anatomical information. CT, MRI and ultrasound are essentially used for anatomical information; MRI and ultrasound are essentially used for anatomical information; the functional information they provide is limited. The converse is the functional information they provide is limited. The converse is true of radionuclide examinations where functional information is true of radionuclide examinations where functional information is paramount.paramount.

Ultrasound is the first-line investigation to demonstrate or exclude Ultrasound is the first-line investigation to demonstrate or exclude hydronephrosis, particularly in patients with renal failure, and to hydronephrosis, particularly in patients with renal failure, and to diagnose renal tumours, cysts and abscesses.diagnose renal tumours, cysts and abscesses.

Computed tomography is preeminent for staging renal tumours, for Computed tomography is preeminent for staging renal tumours, for diagnosing or excluding trauma to the urinary tract and for showing diagnosing or excluding trauma to the urinary tract and for showing pathology in the retroperitoneum.pathology in the retroperitoneum.

Radiographic Radiographic Evaluation of the Urinary Evaluation of the Urinary

SystemSystem A plain x-ray of the abdomen (kidney, ureter, bladder [KUB]) is performed first to A plain x-ray of the abdomen (kidney, ureter, bladder [KUB]) is performed first to

demonstrate the size and location of the kidneys. Since gastrointestinal and urinary demonstrate the size and location of the kidneys. Since gastrointestinal and urinary system diseases tend to mimic each other, the x-ray may be helpful in differential system diseases tend to mimic each other, the x-ray may be helpful in differential diagnosis However, the renal outline can be obscured by bowel content, lack of diagnosis However, the renal outline can be obscured by bowel content, lack of perinephric fat, or a perinephric hematoma or abscess. This difficulty may be perinephric fat, or a perinephric hematoma or abscess. This difficulty may be overcome by tomography. Congenital absence of a kidney may be suggested. If overcome by tomography. Congenital absence of a kidney may be suggested. If both kidneys are unusually large, polycystic kidney disease, multiple myeloma, both kidneys are unusually large, polycystic kidney disease, multiple myeloma, lymphoma, amyloid disease, or hydronephrosis may be present If both are small, lymphoma, amyloid disease, or hydronephrosis may be present If both are small, the end stage of glomerulonephritis or bilateral atrophic pyelonephritis must be the end stage of glomerulonephritis or bilateral atrophic pyelonephritis must be considered. Unilateral enlargement should suggest renal tumor, cyst, or considered. Unilateral enlargement should suggest renal tumor, cyst, or hydronephrosis, whereas a small kidney on one side is compatible with congenital hydronephrosis, whereas a small kidney on one side is compatible with congenital hypoplasia, atrophic pyelonephritis, or an ischemic kidney Normally, the left kidney hypoplasia, atrophic pyelonephritis, or an ischemic kidney Normally, the left kidney is 0.5 cm longer than its mate.is 0.5 cm longer than its mate.

In 90% of cases, the right kidney is lower than the left because of displacement by In 90% of cases, the right kidney is lower than the left because of displacement by the liver. The long axes of the kidneys are oblique to the spine and tend to parallel the liver. The long axes of the kidneys are oblique to the spine and tend to parallel the borders of the psoas muscles. If both kidneys are parallel to the spine, the the borders of the psoas muscles. If both kidneys are parallel to the spine, the possibility of horseshoe kidneys should be considered. If only one kidney is possibility of horseshoe kidneys should be considered. If only one kidney is displaced, a tumor or cyst should be considereddisplaced, a tumor or cyst should be considered Because an x-ray film is two-Because an x-ray film is two-dimensional, a positive diagnosis of a stone in the urinary tract is practically dimensional, a positive diagnosis of a stone in the urinary tract is practically impossible except in the instance of a staghorn calculus. However, suspicious impossible except in the instance of a staghorn calculus. However, suspicious opaque bodies may be noted in the region of the adrenal, kidney, ureter, bladder, or opaque bodies may be noted in the region of the adrenal, kidney, ureter, bladder, or prostate. Oblique and lateral films, as well as visualization of the urinary tract with prostate. Oblique and lateral films, as well as visualization of the urinary tract with radiopaque fluids, are necessary in order to place the calcification specifically radiopaque fluids, are necessary in order to place the calcification specifically within these organs.within these organs.

An excretory urogram is used to visualize the kidney and lower urinary tract. Studies are done by an IV infusion of a triiodinated benzoic acid derivative. The iodine molecule provides radiopacity, while the benzoic acid molecule is rapidly filtered by the kidney. After IV injection of a contrast agent, the drug becomes concentrated in the renal tubules within the first 5 min, providing a nephrogram. Later, the contrast agent appears in the collecting system, outlining the renal pelvis, the ureters, and finally the bladder. This ability to visualize the urinary system is dependent on adequate renal function and, to some degree, on the absence of an osmotic or water diuresis which would dilute the contrast agent. Therefore, the best radiograms are obtained in patients with a normal GFR who have been water-restricted. It is usually difficult to obtain an adequate study in patients with a BUN > 70 mg/dl or a plasma creatinine > 7 mg/dl. Excretory urograms are indicated when disease of the urinary tract is suspected. This test may be useful in investigating cysts and tumors of the kidneys (space-occupying lesions), infections of the kidney (distortion of the calyces), hydronephrosis, vesicoureteral reflux, hypertension, and Iithiasis. If renal injury is suspected, excretory urography should be done to make certain that the contralateral uninjured kidney is normal, and to obtain functional information about the injured kidney. Finally, excretory urograms are indispensable in infants, particularly males, for whom cystoscopy may be unduly traumatic.

The The retrograde pyelogram retrograde pyelogram is a procedure in which radiopaque agents similar is a procedure in which radiopaque agents similar to those used in excretory urography are introduced directly into the urinary to those used in excretory urography are introduced directly into the urinary tract following cystoscopy and catheterization of the ureter. The technic tract following cystoscopy and catheterization of the ureter. The technic provides more intense opacification of the collecting and voiding system when provides more intense opacification of the collecting and voiding system when the excretory urogram has been unsuccessful owing to poor renal function. the excretory urogram has been unsuccessful owing to poor renal function. Retrograde evaluation may also be indicated to assess the degree of ureteral Retrograde evaluation may also be indicated to assess the degree of ureteral obstruction or when the patient is allergic to IV radiopaque chemicals.obstruction or when the patient is allergic to IV radiopaque chemicals.

The The cystogram cystogram is obtained as a part of the excretory urogram but may be is obtained as a part of the excretory urogram but may be unsatisfactory owing to poor opacification or incomplete filling. Controlled unsatisfactory owing to poor opacification or incomplete filling. Controlled blad der filling utilizing a catheter blad der filling utilizing a catheter (retrograde cystogram) (retrograde cystogram) is then necessary is then necessary for ade quate visualization. Retrograde cystograms are advisable for study of for ade quate visualization. Retrograde cystograms are advisable for study of neurogenic bladder, bladder rupture, or recurrent urinary tract infections. Such neurogenic bladder, bladder rupture, or recurrent urinary tract infections. Such causes as vesicoureteral reflux or vesical fistulas are best diagnosed by this causes as vesicoureteral reflux or vesical fistulas are best diagnosed by this technic.technic.

The male urethra may be examined by the retrograde injection of a contrast The male urethra may be examined by the retrograde injection of a contrast agent, although the information needed is frequently seen in a voiding film agent, although the information needed is frequently seen in a voiding film after an excretory urogram. When the retrograde urethral injection is after an excretory urogram. When the retrograde urethral injection is combined with this cystography, the combined procedure is called combined with this cystography, the combined procedure is called retrograde retrograde urethrocystography.urethrocystography.

For special problems concerning the integrity of the renal blood supply, con For special problems concerning the integrity of the renal blood supply, con trast media may be selectively injected into the arterial supply trast media may be selectively injected into the arterial supply (arteriography) (arteriography) or the venous system or the venous system (venography).(venography).

Renal Evaluation with RadioisotopesRenal Evaluation with Radioisotopes Radionuclides Radionuclides which are selectively accumulated or secreted by the kidney permit which are selectively accumulated or secreted by the kidney permit

evaluation of renal structure and function without introducing the hyper tonic and evaluation of renal structure and function without introducing the hyper tonic and chemical stress of IV contrast agents. Because of the trace amounts given, the chemical stress of IV contrast agents. Because of the trace amounts given, the danger of hypersensitivity is decreased and, with the use of rapidly decaying danger of hypersensitivity is decreased and, with the use of rapidly decaying isotopes, the biologic damage from radiation is small The particular advantage of isotopes, the biologic damage from radiation is small The particular advantage of radioisotopic scintiphotography over x-rays is the ease with which radioisotope radioisotopic scintiphotography over x-rays is the ease with which radioisotope concentration can be estimated by counting radioactive disintegrations while a concentration can be estimated by counting radioactive disintegrations while a simultaneous image of radioisotope dilution is produced Thus, static as well as simultaneous image of radioisotope dilution is produced Thus, static as well as dynamic studies are possible While x-ray images are not readily susceptible to dynamic studies are possible While x-ray images are not readily susceptible to numerical quantitation, they do have a higher resolution than radioisotope images.numerical quantitation, they do have a higher resolution than radioisotope images.All of the radiopharmaceuticals currently used for renal evaluation are labeled with All of the radiopharmaceuticals currently used for renal evaluation are labeled with γ-emitting radionuclides γ -Radiation penetrates tissue as do x-rays and is detected γ-emitting radionuclides γ -Radiation penetrates tissue as do x-rays and is detected by the γ-camera Current technology allows a continuous dynamic observation of the by the γ-camera Current technology allows a continuous dynamic observation of the radioactivity accumulating in the urinary system Accumulation in the kidney of any radioactivity accumulating in the urinary system Accumulation in the kidney of any of these chemicals is dependent initially upon renal blood flow, which is sufficiently of these chemicals is dependent initially upon renal blood flow, which is sufficiently large that the kidneys are seen as well-defined images with relatively little labeling large that the kidneys are seen as well-defined images with relatively little labeling of surrounding structures Thus, isotopic studies can be used to determine of surrounding structures Thus, isotopic studies can be used to determine vascularity in any renal mass lesion A "cold" area with little radioactivity suggests a vascularity in any renal mass lesion A "cold" area with little radioactivity suggests a lack of vascularity and, if spherical, a cyst An area of high vascularity suggests a lack of vascularity and, if spherical, a cyst An area of high vascularity suggests a vascular tumor, usually a neoplasm Vascular tu mors often demonstrate greatest vascular tumor, usually a neoplasm Vascular tu mors often demonstrate greatest uptake of radioactivity at a time which differs from that of the uninvolved renal uptake of radioactivity at a time which differs from that of the uninvolved renal cortex In the presence of neoplastic disease, the surrounding renal cortex may show cortex In the presence of neoplastic disease, the surrounding renal cortex may show reduced blood flow due to the local pressure of the tumor or to invasion of vascular reduced blood flow due to the local pressure of the tumor or to invasion of vascular structures Simple cysts tend to cause discrete spherical defects without other structures Simple cysts tend to cause discrete spherical defects without other disturbance of renal cortical blood flow.disturbance of renal cortical blood flow.

Renal Evaluation with RadioisotopesRenal Evaluation with Radioisotopes

ScintiphotographyScintiphotography also provides an opportunity to determine also provides an opportunity to determine the presence of regional renal ischemia causing renal vascular the presence of regional renal ischemia causing renal vascular hypertension The site of regional renal ischemia often may be hypertension The site of regional renal ischemia often may be defined, rather than just comparing one entire kidney to the defined, rather than just comparing one entire kidney to the other Scintiphotography is also an excellent tool for evaluating other Scintiphotography is also an excellent tool for evaluating the success of vascular and ureteral anastomoses in the period the success of vascular and ureteral anastomoses in the period immediately following trans plantation In evaluation of renal immediately following trans plantation In evaluation of renal trauma, radioisotopic studies are useful in the diagnosis of trauma, radioisotopic studies are useful in the diagnosis of extrarenal hematoma, renal lacerations, reduction of renal extrarenal hematoma, renal lacerations, reduction of renal function secondary to contusion, or urine extravasation Lastly, function secondary to contusion, or urine extravasation Lastly, radioisotopes may be useful in obstructive uropathy and may radioisotopes may be useful in obstructive uropathy and may give sufficient structural delineation to obviate the need for give sufficient structural delineation to obviate the need for retrograde urography.retrograde urography.

Ultrasound Evaluation of the Urinary Ultrasound Evaluation of the Urinary SystemSystem

Ultrasonic technics are increasingly being used to evaluate urinary system Ultrasonic technics are increasingly being used to evaluate urinary system disease Much of the information obtained is purely anatomic, but the disease Much of the information obtained is purely anatomic, but the technic has the advantage that visualization does not depend on function technic has the advantage that visualization does not depend on function Nevertheless, some functional information can be inferred, especially in the Nevertheless, some functional information can be inferred, especially in the fetus, in whom the kidneys can be identified with certainty after about 20 fetus, in whom the kidneys can be identified with certainty after about 20 wk gestation, permitting measurement of urine production rate by serial wk gestation, permitting measurement of urine production rate by serial estimations of the bladder volume Fetal hydronephrosis, polycystic kidney, estimations of the bladder volume Fetal hydronephrosis, polycystic kidney, and bladder neck obstruction have also been detected In the neonatal and bladder neck obstruction have also been detected In the neonatal period, ultrasound should be the first-choice technic for investigating period, ultrasound should be the first-choice technic for investigating abdominal masses, for the results may be 95 to 98% accurateabdominal masses, for the results may be 95 to 98% accurate

Ultrasound is extremely accurate in differentiating solid from cystic masses Ultrasound is extremely accurate in differentiating solid from cystic masses in patients of all ages Since ultrasound examinations are innocuous, they in patients of all ages Since ultrasound examinations are innocuous, they are also useful for the follow-up of known lesions, either without treatmentare also useful for the follow-up of known lesions, either without treatment—such as cysts incidentally detected—or after treatment for —such as cysts incidentally detected—or after treatment for hydronephrosis or calculus This is especially the case in younger patients, hydronephrosis or calculus This is especially the case in younger patients, in whom repeated radiographic examination is best avoided In transplanted in whom repeated radiographic examination is best avoided In transplanted kidneys, ultrasound has been used to detect and follow the progression of kidneys, ultrasound has been used to detect and follow the progression of perinephric fluid collections Recent developments in ultrasound suggest perinephric fluid collections Recent developments in ultrasound suggest the possibility of estimating blood flow in the kidney.the possibility of estimating blood flow in the kidney.

Renal BiopsyRenal Biopsy There are four reasons for performing renal biopsies: (1) to help establish a There are four reasons for performing renal biopsies: (1) to help establish a

histologic diagnosis; (2) to help estimate prognosis and the potential histologic diagnosis; (2) to help estimate prognosis and the potential reversibility or progression of the renal lesion; (3) to estimate the value of reversibility or progression of the renal lesion; (3) to estimate the value of therapeutic modalities; and (4) to determine the natural history of renal therapeutic modalities; and (4) to determine the natural history of renal diseases. The only absolute contraindication to a biopsy is an uncontrollable diseases. The only absolute contraindication to a biopsy is an uncontrollable bleeding disorder. The biopsy of a solitary kidney is a relative bleeding disorder. The biopsy of a solitary kidney is a relative contraindication to be weighed against the need for information. Biopsies of contraindication to be weighed against the need for information. Biopsies of a single, functioning, transplanted kidney are done frequently to diagnose a single, functioning, transplanted kidney are done frequently to diagnose and study possible graft rejections. Conditions associated with an increased and study possible graft rejections. Conditions associated with an increased morbidity following biopsy are deemed relative contraindications; these morbidity following biopsy are deemed relative contraindications; these include renal tumors, large renal cysts, hydronephrosis, perinephric include renal tumors, large renal cysts, hydronephrosis, perinephric abscesses, severe reduction in blood or plasma volume, severe hypertension, abscesses, severe reduction in blood or plasma volume, severe hypertension, and advanced renal failure with symptoms of uremia.and advanced renal failure with symptoms of uremia.

There are two biopsy technics, There are two biopsy technics, open open and and percutaneous; percutaneous; the percutaneous the percutaneous tech-nic is most common. The open surgical method is rarely necessary—tech-nic is most common. The open surgical method is rarely necessary—only when the percutaneous method has been unsuccessful or when direct only when the percutaneous method has been unsuccessful or when direct visual control of the biopsy is deemed critical. For the percutaneous technic visual control of the biopsy is deemed critical. For the percutaneous technic the patient is sedated, and the kidney is visualized by radiographic or the patient is sedated, and the kidney is visualized by radiographic or ultrasonic technics. With the patient in the prone position and following ultrasonic technics. With the patient in the prone position and following local anesthesia of the overlying skin and muscles of the back, the biopsy local anesthesia of the overlying skin and muscles of the back, the biopsy needle is inserted and tissue is obtained for light, electron, and needle is inserted and tissue is obtained for light, electron, and immunofluorescent microscopy.immunofluorescent microscopy.

Oblique views to determine whether Oblique views to determine whether calcifications are intra- or extrarenal. calcifications are intra- or extrarenal. (a) A rounded calcification is seen (a) A rounded calcification is seen overlying the left kidney in the AP plain overlying the left kidney in the AP plain film, film, (b) In the oblique plain film, the (b) In the oblique plain film, the calcification is in the same position within calcification is in the same position within the renal shadow and is, therefore, a renal the renal shadow and is, therefore, a renal calculus, calculus, (c) A rounded calcification is seen over the (c) A rounded calcification is seen over the right renal shadow, right renal shadow, (d) An oblique film after contrast shows (d) An oblique film after contrast shows that the calcification lies outside the that the calcification lies outside the kidney. It was later confirmed to be a gall kidney. It was later confirmed to be a gall stonestone

Normal IVU. Full length 15min film. Note Normal IVU. Full length 15min film. Note

that the bladder is well opacified. The that the bladder is well opacified. The

whole of the right ureter and part of the whole of the right ureter and part of the

left ureter are seen. Often, only a portion left ureter are seen. Often, only a portion

of the ureter is visualized owing to of the ureter is visualized owing to

peristalsis emptying certain sections. The peristalsis emptying certain sections. The

bladder outline is reasonably smooth. The bladder outline is reasonably smooth. The

roof of the bladder shows a shallow roof of the bladder shows a shallow

indentation from the uterus.indentation from the uterus.

Large calcified calculus in Large calcified calculus in the pelvis of the kidney the pelvis of the kidney obscured by contrast obscured by contrast medium. Since the contrast medium. Since the contrast medium and the calculus medium and the calculus have the same radiographic have the same radiographic density, the calculus is density, the calculus is hidden by the contrast hidden by the contrast medium.medium.

Renal mass. A Renal mass. A renal cyst renal cyst (arrows) has (arrows) has caused a bulge caused a bulge on the lateral on the lateral aspect of the aspect of the kidney with kidney with splaying of the splaying of the calices.calices.

The calices. The calices. (a) Normal calices. Each calix is 'cup-shaped', (a) Normal calices. Each calix is 'cup-shaped', (b) Many of the calices are clubbed. There is scarring of the (b) Many of the calices are clubbed. There is scarring of the parenchyma of the upper half of the kidney indicating that the parenchyma of the upper half of the kidney indicating that the diagnosis is chronic pyelonephritis, diagnosis is chronic pyelonephritis, (c) All the calices are dilated, the dilatation of the collecting (c) All the calices are dilated, the dilatation of the collecting system extending down to the point of obstruction (arrow), in this system extending down to the point of obstruction (arrow), in this case owing to a malignant retroperitoneal lymph nodecase owing to a malignant retroperitoneal lymph node

At ultrasound, the kidneys should be smooth in At ultrasound, the kidneys should be smooth in outline. The parenchyma surrounds a central outline. The parenchyma surrounds a central echodense region, known as the central echo complex echodense region, known as the central echo complex (also called the renal sinus), consisting of the (also called the renal sinus), consisting of the pelvicaliceal system, together with sur rounding fat pelvicaliceal system, together with sur rounding fat and renal blood vessels. In most instances, the normal and renal blood vessels. In most instances, the normal pelvicaliceal system is not separately visualized. The pelvicaliceal system is not separately visualized. The renal cortex generates homogeneous echoes which renal cortex generates homogeneous echoes which are less intense than those of the adjacent liver or are less intense than those of the adjacent liver or spleen and the renal pyramids are seen as triangular spleen and the renal pyramids are seen as triangular sonolucent areas adja cent to the renal sinus. During sonolucent areas adja cent to the renal sinus. During the first two months of life, cortical echoes are the first two months of life, cortical echoes are relatively more prominent and the renal pyramids are relatively more prominent and the renal pyramids are strikingly sonolucent.strikingly sonolucent.

Normal renal ultrasound

The normal adult renal length, measured by ultrasound, is 9-12cm. These figures The normal adult renal length, measured by ultrasound, is 9-12cm. These figures are lower than those for renal size measured by IVU, because there is no swelling are lower than those for renal size measured by IVU, because there is no swelling from the action of contrast medium and there is no magnification of the image.from the action of contrast medium and there is no magnification of the image.Normal ureters are not usually visualized. The urinary bladder should be Normal ureters are not usually visualized. The urinary bladder should be examined in the distended state: the walls should be sharply defined and barely examined in the distended state: the walls should be sharply defined and barely perceptible.perceptible.

CT and MRICT and MRIComputed tomography is used for specific indications,Computed tomography is used for specific indications, often after IVU or ultrasound have identified a problem. often after IVU or ultrasound have identified a problem.Like ultrasound, CT can characterize masses and it showsLike ultrasound, CT can characterize masses and it showsthe retroperitoneal space.the retroperitoneal space. It is an extremely sensitive method of detecting calculi and It is an extremely sensitive method of detecting calculi andI is also useful when assessing trauma or infarction. The technique is I is also useful when assessing trauma or infarction. The technique is virtually the same as for standard abdominal and pelvic CT, except that virtually the same as for standard abdominal and pelvic CT, except that sections of the kidneys are usually performed both before and after intra sections of the kidneys are usually performed both before and after intra venous contrast medium has been given.venous contrast medium has been given.Magnetic resonance imaging gives similar information to CT, with a few Magnetic resonance imaging gives similar information to CT, with a few specific advantages, but it has several disadvantages and is only used in specific advantages, but it has several disadvantages and is only used in selected circumstances, e.g. demonstrating renal artery stenosis and inferior selected circumstances, e.g. demonstrating renal artery stenosis and inferior vena caval extension of renal tumours.vena caval extension of renal tumours.

Normal CTNormal CT The basic principles of interpretation are the same as for IVU. The The basic principles of interpretation are the same as for IVU. The renal parenchyma should have a smooth outline and opacify renal parenchyma should have a smooth outline and opacify uniformly after intravenous contrast administration, although uniformly after intravenous contrast administration, although early images may show opacification of the cortex before medullary early images may show opacification of the cortex before medullary opacification has had time to occur. The pelvicaliceal system should opacification has had time to occur. The pelvicaliceal system should show cupped calices with uniform width of renal parenchyma from show cupped calices with uniform width of renal parenchyma from calix to renal edge, and the fat that surrounds the pelvicaliceal calix to renal edge, and the fat that surrounds the pelvicaliceal system should be clearly visualized. The ureters are seen in cross-system should be clearly visualized. The ureters are seen in cross-section as dots lying on the psoas muscles. They will not necessarily section as dots lying on the psoas muscles. They will not necessarily be seen at all levels because peristalsis obliterates the lumen be seen at all levels because peristalsis obliterates the lumen intermittently. The bladder has a smooth outline contrasted against intermittently. The bladder has a smooth outline contrasted against the pelvic fat; its wall is thin and of reasonably uniform diameter. the pelvic fat; its wall is thin and of reasonably uniform diameter. Contrast opacification of the urine in the bladder is variable Contrast opacification of the urine in the bladder is variable depend ing on how much contrast has reached the bladder. The con depend ing on how much contrast has reached the bladder. The con trast medium is heavier than urine and therefore, the dependent trast medium is heavier than urine and therefore, the dependent portion is usually more densely opacified.portion is usually more densely opacified.

Normal CT of kidneys and bladder, (a), (b) Adjacent sections, (b) 1 cm higher than Normal CT of kidneys and bladder, (a), (b) Adjacent sections, (b) 1 cm higher than (a), showing uniform opacification of parenchyma with well-defined cortical edge. (a), showing uniform opacification of parenchyma with well-defined cortical edge. The pelvicaliceal system, which is densely opacified, is surrounded by fat. The renal The pelvicaliceal system, which is densely opacified, is surrounded by fat. The renal veins are well shown on the higher section, (c) (not present) Section through the level veins are well shown on the higher section, (c) (not present) Section through the level of the ureters (arrows) after contrast has been given, (d) Section through opacified of the ureters (arrows) after contrast has been given, (d) Section through opacified bladder in a male patient shows that the bladder wall is too thin to be seen. Note the bladder in a male patient shows that the bladder wall is too thin to be seen. Note the layering of contrast medium, (e) Section through bladder without contrast layering of contrast medium, (e) Section through bladder without contrast opacification. The bladder wall can be identified as a thin line. A, aorta; I, inferior opacification. The bladder wall can be identified as a thin line. A, aorta; I, inferior vena cava; K, kidney; P, pelvis; RV, renal vein; Sp, spine.vena cava; K, kidney; P, pelvis; RV, renal vein; Sp, spine.

Radionuclide Radionuclide examinationexamination

There are two main radionuclide There are two main radionuclide techniques for studying the kidneys:techniques for studying the kidneys:

The renogram which measures renal The renogram which measures renal function. Scans of renal morphology function. Scans of renal morphology (DMSA scan). The advent of CT and (DMSA scan). The advent of CT and ultrasound has reduced the need for ultrasound has reduced the need for such scans. They are now used such scans. They are now used mainly for evaluating renal scanning.mainly for evaluating renal scanning.

Renogram Renogram If substances which pass into the urine are labelled with a radionuclide and injected If substances which pass into the urine are labelled with a radionuclide and injected

intravenously, their passage through the kidney can be observed with a gamma intravenously, their passage through the kidney can be observed with a gamma camera.camera.

The two agents of choice are "«The two agents of choice are "«ТсТс DTPA (diethylene triamine pentacetic acid) and DTPA (diethylene triamine pentacetic acid) and ^mjc MAG-3 (mercaptoacetyl triglycine). DTPA is filtered by the glomeruli and ^mjc MAG-3 (mercaptoacetyl triglycine). DTPA is filtered by the glomeruli and not absorbed or secreted by the tubules, whereas MAG-3 is both filtered by the not absorbed or secreted by the tubules, whereas MAG-3 is both filtered by the glomeruli and secreted by the tubules.glomeruli and secreted by the tubules.

The gamma camera is positioned posteriorly over the kidneys and a rapid injection The gamma camera is positioned posteriorly over the kidneys and a rapid injection of the radiopharmaceutical is given. Early images show the major blood vessels of the radiopharmaceutical is given. Early images show the major blood vessels and both kidneys. Subsequently, activity is seen in the renal parenchyma and by and both kidneys. Subsequently, activity is seen in the renal parenchyma and by 5min the collecting systems should be visible. Serial images over 20min show 5min the collecting systems should be visible. Serial images over 20min show progressive excre tion and clearance of activity from the kidneys. Quantitative progressive excre tion and clearance of activity from the kidneys. Quantitative assessment with a computer enables a renogram curve toassessment with a computer enables a renogram curve to be produced and the be produced and the relative function of each kidney calculated. The main indications for a renogram relative function of each kidney calculated. The main indications for a renogram are:are:– measurement of relative renal function in each kidney -measurement of relative renal function in each kidney -

this may help the surgeon decide between nephrectomy orthis may help the surgeon decide between nephrectomy ormore conservative surgery;more conservative surgery;

– investigation of urinary tract obstruction, particularlyinvestigation of urinary tract obstruction, particularlypelviureteric junction obstruction;pelviureteric junction obstruction;

– investigation of renal transplantsinvestigation of renal transplants

The renogram curve. a)Vascular phase. b) Filtration phase, (c) Excretion The renogram curve. a)Vascular phase. b) Filtration phase, (c) Excretion phase, (d)phase, (d)

Minutes after injection

Right kidney

4 12

Retrograde and antegrade pyelographyRetrograde and antegrade pyelographyThe techniques of retrograde and antegrade pyelography (the term pyelography The techniques of retrograde and antegrade pyelography (the term pyelography means demonstrating the pelvical-iceal system and ureters) involve direct injection means demonstrating the pelvical-iceal system and ureters) involve direct injection of contrast material into the pelvicaliceal system or ureters through catheters placed of contrast material into the pelvicaliceal system or ureters through catheters placed via cystoscopy (retrograde pyelography) or percutaneously into the kidney via the via cystoscopy (retrograde pyelography) or percutaneously into the kidney via the loin (antegrade pyelography). The indications are limited to those situa tions where loin (antegrade pyelography). The indications are limited to those situa tions where the information cannot be achieved by less invasive means, for example in those few the information cannot be achieved by less invasive means, for example in those few cases of hydronephrosis where further information about the level and nature of cases of hydronephrosis where further information about the level and nature of obstruction is required.obstruction is required.

Plain film showing a calcified Plain film showing a calcified

staghorn calculus in each kidney.staghorn calculus in each kidney.

Ultrasound of stone in right kidney. The stone (arrow) Ultrasound of stone in right kidney. The stone (arrow) appears as a bright echo. Note the acoustic shadow appears as a bright echo. Note the acoustic shadow behind the stone (double headed arrow).behind the stone (double headed arrow).

Nephrocalcinosis. There are Nephrocalcinosis. There are numerous calcifications in the numerous calcifications in the pyramids of both kidneys (the left pyramids of both kidneys (the left kidney is not illustrated).kidney is not illustrated).

Ureteric obstruction. The pelvicaliceal system and ureter are dilated down to the level of the obstructing pathology (arrow), in this instance a small calculus

Acute ureteric obstruction from a stone in the lower end of the left ureter, (a) Acute ureteric obstruction from a stone in the lower end of the left ureter, (a) A film taken 30 min after the injection of contrast medium. There is obvious A film taken 30 min after the injection of contrast medium. There is obvious delay in the appearance of the pyelogram on the left. The left kidney shows a delay in the appearance of the pyelogram on the left. The left kidney shows a very dense nephrogram which is characteristic of acute ureteric obstruction, very dense nephrogram which is characteristic of acute ureteric obstruction, (b) A film taken 23 h later shows opacification of the obstructed collecting (b) A film taken 23 h later shows opacification of the obstructed collecting system down to the obstructing calculus (arrow).system down to the obstructing calculus (arrow).

Dilatation of the pelvicaliceal system, (a) Longitudinal ultrasound scan of right Dilatation of the pelvicaliceal system, (a) Longitudinal ultrasound scan of right kidney showing spreading of the central echo complex of the dilated collecting kidney showing spreading of the central echo complex of the dilated collecting system (arrows), (b) Here the dilatation of the calices is greater (arrows), (c) In this system (arrows), (b) Here the dilatation of the calices is greater (arrows), (c) In this image from a patient with pelviureteric obstruction, the dilated calices resemble image from a patient with pelviureteric obstruction, the dilated calices resemble cysts, (d) CT scan after contrast showing a dilated renal pelvis (asterisk). The vertical cysts, (d) CT scan after contrast showing a dilated renal pelvis (asterisk). The vertical arrow points to a small amount of contrast pooling in a dependent calix. Note the arrow points to a small amount of contrast pooling in a dependent calix. Note the normal left ureter (horizontal arrow).normal left ureter (horizontal arrow).

Renal pseudotumour (arrows) which Renal pseudotumour (arrows) which was subsequently shown to be was subsequently shown to be normal renal cortical tissue.normal renal cortical tissue.

Ultrasound in renal masses, (a) Cyst (C) showing sharp walls and no echoes Ultrasound in renal masses, (a) Cyst (C) showing sharp walls and no echoes arising within the cyst. Note the acoustic enhancement behind the cyst, (b) arising within the cyst. Note the acoustic enhancement behind the cyst, (b) Tumour showing echoes within a solid mass (M). (c) Complex mass due to Tumour showing echoes within a solid mass (M). (c) Complex mass due to cystic renal cell carcinoma. The arrows point to the edge of the mass. Note the cystic renal cell carcinoma. The arrows point to the edge of the mass. Note the thick septa within the mass, (d) Angiomyolipoma. This incidental finding thick septa within the mass, (d) Angiomyolipoma. This incidental finding shows the typical appearance of a small echogenic mass (arrow).shows the typical appearance of a small echogenic mass (arrow).

Computed tomography (contrast-enhanced) in renal masses, (a) Cyst in left kidney Computed tomography (contrast-enhanced) in renal masses, (a) Cyst in left kidney (C) showing a well-defined edge, imperceptible wall and uniform water density. (C) showing a well-defined edge, imperceptible wall and uniform water density. The cyst shows no enhancement. It was an incidental finding, (b) Renal cell The cyst shows no enhancement. It was an incidental finding, (b) Renal cell carcinoma. The mass (arrows) is not clearly demarcated from the adjacent kidney carcinoma. The mass (arrows) is not clearly demarcated from the adjacent kidney and shows substantial enhancement. (c) Angiomyolipoma with a small mass and shows substantial enhancement. (c) Angiomyolipoma with a small mass (arrow) of fat density.(arrow) of fat density.

Staging renal carcinoma, (a) CT scan showing Staging renal carcinoma, (a) CT scan showing a large mass (M) in the left kidney from renal a large mass (M) in the left kidney from renal cell carcinoma and a greatly enlarged lymph cell carcinoma and a greatly enlarged lymph node (arrows) in the left paraaortic area. This node (arrows) in the left paraaortic area. This node contained metastatic tumour cells, (b) node contained metastatic tumour cells, (b) Coronal MRI scan showing a huge left renal Coronal MRI scan showing a huge left renal carcinoma (M) with tumour extending into the carcinoma (M) with tumour extending into the inferior vena cava (IVC) via the left renal inferior vena cava (IVC) via the left renal vein. The caval extension of tumour (*) vein. The caval extension of tumour (*) extends to the top of the IVC. (c) Axial MRI extends to the top of the IVC. (c) Axial MRI scan showing the IVC extension of tumour scan showing the IVC extension of tumour (arrows). Normally, the IVC is seen as a (arrows). Normally, the IVC is seen as a signal void.signal void.

Renal abscess, (a) Ultrasound Renal abscess, (a) Ultrasound scan showing a complex mass scan showing a complex mass (arrows) in the right kidney, (b) (arrows) in the right kidney, (b) CT scan in a different patient CT scan in a different patient showing encapsulated fluid showing encapsulated fluid collection in the lower pole of collection in the lower pole of the right kidney (arrows). D, the right kidney (arrows). D, diaphragm; L, liver; LK, left diaphragm; L, liver; LK, left kidney; RK, right kidney; Sp, kidney; RK, right kidney; Sp, spleen.spleen.

Perinephric abscess. CT scan showing a rounded Perinephric abscess. CT scan showing a rounded loculation of fluid and gas in the left perinephric loculation of fluid and gas in the left perinephric space (arrows).space (arrows).

Renal trauma, (a) The lower pole of the kidney has Renal trauma, (a) The lower pole of the kidney has been ruptured and a pool of extravasated contrast been ruptured and a pool of extravasated contrast can be seen, (b) CT scan showing extensive can be seen, (b) CT scan showing extensive haematoma (arrows) surrounding a fragmented haematoma (arrows) surrounding a fragmented left kidney (K)left kidney (K)

Horseshoe kidneys, (a) The two kidneys are fused at their lower Horseshoe kidneys, (a) The two kidneys are fused at their lower poles. The striking feature is the alteration in the axis of the poles. The striking feature is the alteration in the axis of the kidneys: the lower calices are closer to the spine than the upper kidneys: the lower calices are closer to the spine than the upper calices. The kidneys are rotated so that their pelves point calices. The kidneys are rotated so that their pelves point forward and the lower calices point medially. The medial aspects forward and the lower calices point medially. The medial aspects of the lower poles cannot be identified, (b) CT scan of different of the lower poles cannot be identified, (b) CT scan of different patient, following i.v. contrast enhancement, showing fusion of patient, following i.v. contrast enhancement, showing fusion of the lower poles of the kidneys. K, kidney.the lower poles of the kidneys. K, kidney.

Bladder neoplasm, (a) There is a large filling defect in the left side Bladder neoplasm, (a) There is a large filling defect in the left side of the bladder from a transitional cell carcinoma. Note the of the bladder from a transitional cell carcinoma. Note the obstructive dilatation of the left ureter, (b) Ultrasound scan from a obstructive dilatation of the left ureter, (b) Ultrasound scan from a different patient showing a large tumour (T) within the bladder.different patient showing a large tumour (T) within the bladder.

CT scan of carcinoma of bladder, showing CT scan of carcinoma of bladder, showing an extensive tumour (T) involving the an extensive tumour (T) involving the bladder wall but still confined to the bladder wall but still confined to the bladder.bladder.

Bladder diverticula. Cystogram showing numerous Bladder diverticula. Cystogram showing numerous outpouchings from the bladder with a very large outpouchings from the bladder with a very large diverticulum projecting to the left.diverticulum projecting to the left.

Prostatic enlargement. The bladder base is lifted up and shows an Prostatic enlargement. The bladder base is lifted up and shows an impression from the enlarged prostate (arrows). The ureters are impression from the enlarged prostate (arrows). The ureters are tortuous and enter the bladder horizontally. A balloon catheter is tortuous and enter the bladder horizontally. A balloon catheter is in the bladder.in the bladder.

Prostate carcinoma shown by Prostate carcinoma shown by transrectal ultrasound. T, tumour.transrectal ultrasound. T, tumour.

Carcinoma of the prostate. CT scan showing massively enlarged prostate (P) indenting the bladder. The tumour has spread to involve pelvic lymph nodes. A huge lymph node mass is seen (L). B, bladder; C, colon.

Prostate carcinoma (T) invading lower Prostate carcinoma (T) invading lower

part of bladder, shown on MRI scan (T1-part of bladder, shown on MRI scan (T1-

weighted sagittal section).weighted sagittal section).

Anteriorabdominalwall

Small bowl

Prostatic calcification. Numerous calculi just above Prostatic calcification. Numerous calculi just above

the pubic symphysis are present in the prostate.the pubic symphysis are present in the prostate.

Urethral stricture. An ascending Urethral stricture. An ascending urethrogram showing a stricture in the urethrogram showing a stricture in the penile urethra (arrow). The patient had penile urethra (arrow). The patient had gonorrhoea.gonorrhoea.

MRI of seminoma (arrow) in right testis. The two testes MRI of seminoma (arrow) in right testis. The two testes are well demonstrated. The high signal adjacent to both are well demonstrated. The high signal adjacent to both testes is normal fluid between the layers of the tunica testes is normal fluid between the layers of the tunica vaginalis.vaginalis.

Normal uterus and vagina.Normal uterus and vagina. Longitudinal section. The central echo of uterus (U) corresponds Longitudinal section. The central echo of uterus (U) corresponds to the endometrial cavity; the uterus itself has a homogeneous echo to the endometrial cavity; the uterus itself has a homogeneous echo texture; V, vagina; B, bladder.texture; V, vagina; B, bladder.

Normal ovaries (arrows). Normal ovaries (arrows). Transverse section in 25-year-Transverse section in 25-year-old woman. B, bladder.old woman. B, bladder.

Normal uterus, CT scan. B, bladder; U, uterus.

Normal uterus, sagittal T2-weighted MRI scan. Normal uterus, sagittal T2-weighted MRI scan. There is a high signal from the endometrium (arrows). There is a high signal from the endometrium (arrows). B, bladder; V, vagina.B, bladder; V, vagina.

Ovarian cyst, (a) Longitudinal ultrasound scan to right of midline Ovarian cyst, (a) Longitudinal ultrasound scan to right of midline showing a 5 cm cyst (C) in right ovary with no internal echoes. B, showing a 5 cm cyst (C) in right ovary with no internal echoes. B, bladder, (b) CT scan of same patient showing the cyst in the right bladder, (b) CT scan of same patient showing the cyst in the right ovary (arrows). Note the uniform water density centre of the cyst, ovary (arrows). Note the uniform water density centre of the cyst, (c) Coronal T2-weighted MRI scan showing a left sided ovarian (c) Coronal T2-weighted MRI scan showing a left sided ovarian cyst (arrows) in a patient with an enlarged uterus due to cyst (arrows) in a patient with an enlarged uterus due to adenomyosis. B, bladder; U, uterus.adenomyosis. B, bladder; U, uterus.

Ovarian carcinoma, (a) Longitudinal ultrasound scan showing a very large Ovarian carcinoma, (a) Longitudinal ultrasound scan showing a very large multilocular cystic tumour containing septa (S) and solid nodules (N). The lesion multilocular cystic tumour containing septa (S) and solid nodules (N). The lesion was a cystadenocarcinoma. (b) CT scan showing large partly cystic, partly solid was a cystadenocarcinoma. (b) CT scan showing large partly cystic, partly solid ovarian carcinoma (arrows). The tumour, which contains irregular areas of ovarian carcinoma (arrows). The tumour, which contains irregular areas of calcification, has invaded the right side of the bladder (B). The rectum is calcification, has invaded the right side of the bladder (B). The rectum is indicated by a curved arrow, (c) MRI scan showing a partly solid (arrows) and indicated by a curved arrow, (c) MRI scan showing a partly solid (arrows) and partly cystic tumour. The cystic component shows as a high signal on this T2-partly cystic tumour. The cystic component shows as a high signal on this T2-weighted scan. B, bladder.weighted scan. B, bladder.