Radiological examination of
the urinary tract and retroperitoneal space.
DEPARTMENT OF ONCOLOGY
AND RADIOLOGY
PREPARED BY I.M.LESKIV
RENAL STRUCTURE AND
FUNCTION
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The kidneys control the volume, composition, and
pressure of body fluids by regulating the excretion
of water and solutes. They also influence red cell
production and blood pressure by hormonal
mechanisms. Urine is formed in the kidneys as an
aqueous solution containing metabolic waste
products, foreign substances, and water-soluble
constituents of the body in quantities depending
upon homeostatic needs.
Anatomy
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The kidneys are bilateral, retroperitoneal structures, each consisting of an
outer cortex and an inner medulla. The medulla is arranged into several coneshaped or; pyramidal projections separated from each other by sections of
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
renal pelvis. The; cortex contains glomeruli and tubules; the medulla, tubules
only.
The kidneys possess numerous blood vessels and because of their low
vascular resistance receive approximately 1200 ml of blood or 25% of the
cardiac output each minute.
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,
changes in renal arterial pressure produce proportional variations in the
afferent arteriolar resistance, which tends to preserve a constant renal blood
flow (RBF) and glomerular capillary pressure; i.e., autoregulation. In addition
to autoregulatioaj the renal circulation is controlled by extrinsic factors such
as neurogenic (sympathetic) and hormonal (epinephrine, norepinephrine, and
angiotensin) regulators. I
Sagittal section of the kidney. The upper half depicts the overall
gross anatomic arrangement The lower half demonstrates the
arterial supply.
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The Nephron
The basic functional unit of the
kidney is the nephron, a long
tubular structure made up of
successive segments of diverse
structure and transport
functions. It includes (1) a renal
corpuscle (Bowman's capsule
and the glomerulus, a tuft of
capillaries), (2) a proximal
tubule (convoluted and straight
portion), (3) a hairpin loop
(Henle's loop), (4) a distal
tubule (straight portion, macula
densa, and convoluted portion),
and (5) a collecting duct system.
There are approximately one
million nephrons in each human
kidney; 85% are cortical
nephrons with short loops of
Henle, and 15% are
juxtamedullary nephrons with
glomeruli near the cortical
medullary junction and with
long, thin, looping segments
Glomerular Filtration
The glomerulus acts as an
ultrafilter, allowing passage
of water, electrolytes, and
small organic molecules
such as glucose, but not
blood cells and large protein
molecules. The ultrafiltrate
produced by the glomeruli
of both kidneys amounts to
about 70 ml/min/sq m or
150 L/day/sq m; this rate is
termed the glomerular
filtration rate (GFR). About
99% of the glomerular
filtrate is resorbed during
passage through the renal
tubules, with most of the
resorption taking place in
the proximal tubules.
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The Concept of "Clearance" and the
Measurement of GFR
A principal function of the kidney is to remove
or "clear" various solutes from the blood
which are not essential to the body, and to
conserve those that the body requires. A solute
is never totally removed from the blood in any
one passage through the kidneys; rather, a
portion is removed during each sweep of the
blood through the renal system. Clearance may
be defined as the volume of plasma which is
completely cleared of a solute in a unit of time
and is usually expressed in ml/min. Stated
another way, the renal clearance of a
substance represents the volume of blood that
would have to pass through the nephrons
within a given time period to provide the
amount of that substance in the urine.
Substances which are rapidly eliminated have
a high clearance; those eliminated slowly, a
low clearance.
Radiological examination
of the urinary tract
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The four basic examinations of the urinary tract are intravenous
urography (IVU), computed tomography (CT), ultrasound and
radionuclide examinations. Magnetic resonance imaging (MRI),
arteriography and studies requiring catheterization or direct puncture
of the collecting systems are limited to highly selected patients.
The IVU provides both functional and anatomical information. CT,
MRI and ultrasound are essentially used for anatomical information;
the functional information they provide is limited. The converse is
true of radionuclide examinations where functional information is
paramount.
Ultrasound is the first-line investigation to demonstrate or exclude
hydronephrosis, particularly in patients with renal failure, and to
diagnose renal tumours, cysts and abscesses.
Computed tomography is preeminent for staging renal tumours, for
diagnosing or excluding trauma to the urinary tract and for showing
pathology in the retroperitoneum.
Radiographic Evaluation of the Urinary System
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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
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
perinephric fat, or a perinephric hematoma or abscess. This difficulty may be
overcome by tomography. Congenital absence of a kidney may be suggested. If both
kidneys are unusually large, polycystic kidney disease, multiple myeloma,
lymphoma, amyloid disease, or hydronephrosis may be present If both are small, the
end stage of glomerulonephritis or bilateral atrophic pyelonephritis must be
considered. Unilateral enlargement should suggest renal tumor, cyst, or
hydronephrosis, whereas a small kidney on one side is compatible with congenital
hypoplasia, atrophic pyelonephritis, or an ischemic kidney Normally, the left kidney
is 0.5 cm longer than its mate.
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 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
displaced, a tumor or cyst should be considered Because an x-ray film is twodimensional, a positive diagnosis of a stone in the urinary tract is practically
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
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 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 waterrestricted. 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.
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The retrograde pyelogram is a procedure in which radiopaque agents similar
to those used in excretory urography are introduced directly into the urinary
tract following cystoscopy and catheterization of the ureter. The technic
provides more intense opacification of the collecting and voiding system when
the excretory urogram has been unsuccessful owing to poor renal function.
Retrograde evaluation may also be indicated to assess the degree of ureteral
obstruction or when the patient is allergic to IV radiopaque chemicals.
The cystogram is obtained as a part of the excretory urogram but may be
unsatisfactory owing to poor opacification or incomplete filling. Controlled
bladder filling utilizing a catheter (retrograde cystogram) is then necessary
for adequate visualization. Retrograde cystograms are advisable for study of
neurogenic bladder, bladder rupture, or recurrent urinary tract infections. Such
causes as vesicoureteral reflux or vesical fistulas are best diagnosed by this
technic.
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
after an excretory urogram. When the retrograde urethral injection is combined
with this cystography, the combined procedure is called retrograde
urethrocystography.
For special problems concerning the integrity of the renal blood supply, contrast media may be selectively injected into the arterial supply (arteriography)
or the venous system (venography).
Renal Evaluation with Radioisotopes
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Radionuclides which are selectively accumulated or secreted by the kidney permit
evaluation of renal structure and function without introducing the hypertonic and
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
isotopes, the biologic damage from radiation is small The particular advantage of
radioisotopic scintiphotography over x-rays is the ease with which radioisotope
concentration can be estimated by counting radioactive disintegrations while a
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
numerical quantitation, they do have a higher resolution than radioisotope images.
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
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
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
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 lack of
vascularity and, if spherical, a cyst An area of high vascularity suggests a vascular
tumor, usually a neoplasm Vascular tumors often demonstrate greatest 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 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
disturbance of renal cortical blood flow.
Renal Evaluation with Radioisotopes
Scintiphotography also provides an opportunity to determine
the presence of regional renal ischemia causing renal vascular
hypertension The site of regional renal ischemia often may be
defined, rather than just comparing one entire kidney to the
other Scintiphotography is also an excellent tool for evaluating
the success of vascular and ureteral anastomoses in the period
immediately following transplantation In evaluation of renal
trauma, radioisotopic studies are useful in the diagnosis of
extrarenal hematoma, renal lacerations, reduction of renal
function secondary to contusion, or urine extravasation Lastly,
radioisotopes may be useful in obstructive uropathy and may
give sufficient structural delineation to obviate the need for
retrograde urography.
Ultrasound Evaluation of the Urinary System
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Ultrasonic technics are increasingly being used to evaluate urinary system
disease Much of the information obtained is purely anatomic, but the
technic has the advantage that visualization does not depend on function
Nevertheless, some functional information can be inferred, especially in the
fetus, in whom the kidneys can be identified with certainty after about 20
wk gestation, permitting measurement of urine production rate by serial
estimations of the bladder volume Fetal hydronephrosis, polycystic kidney,
and bladder neck obstruction have also been detected In the neonatal
period, ultrasound should be the first-choice technic for investigating
abdominal masses, for the results may be 95 to 98% accurate
Ultrasound is extremely accurate in differentiating solid from cystic masses
in patients of all ages Since ultrasound examinations are innocuous, they
are also useful for the follow-up of known lesions, either without
treatment—such as cysts incidentally detected—or after treatment for
hydronephrosis or calculus This is especially the case in younger patients,
in whom repeated radiographic examination is best avoided In transplanted
kidneys, ultrasound has been used to detect and follow the progression of
perinephric fluid collections Recent developments in ultrasound suggest the
possibility of estimating blood flow in the kidney.
Renal Biopsy
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There are four reasons for performing renal biopsies: (1) to help establish a
histologic diagnosis; (2) to help estimate prognosis and the potential
reversibility or progression of the renal lesion; (3) to estimate the value of
therapeutic modalities; and (4) to determine the natural history of renal
diseases. The only absolute contraindication to a biopsy is an uncontrollable
bleeding disorder. The biopsy of a solitary kidney is a relative
contraindication to be weighed against the need for information. Biopsies of
a single, functioning, transplanted kidney are done frequently to diagnose
and study possible graft rejections. Conditions associated with an increased
morbidity following biopsy are deemed relative contraindications; these
include renal tumors, large renal cysts, hydronephrosis, perinephric
abscesses, severe reduction in blood or plasma volume, severe hypertension,
and advanced renal failure with symptoms of uremia.
There are two biopsy technics, open and percutaneous; the percutaneous
tech-nic is most common. The open surgical method is rarely necessary—
only when the percutaneous method has been unsuccessful or when direct
visual control of the biopsy is deemed critical. For the percutaneous technic
the patient is sedated, and the kidney is visualized by radiographic or
ultrasonic technics. With the patient in the prone position and following
local anesthesia of the overlying skin and muscles of the back, the biopsy
needle is inserted and tissue is obtained for light, electron, and
immunofluorescent microscopy.
Oblique views to determine whether
calcifications are intra- or extrarenal.
(a) A rounded calcification is seen overlying
the left kidney in the AP plain film,
(b) In the oblique plain film, the
calcification is in the same position within
the renal shadow and is, therefore, a renal
calculus,
(c) A rounded calcification is seen over the
right renal shadow,
(d) An oblique film after contrast shows
that the calcification lies outside the kidney.
It was later confirmed to be a gall stone
Normal IVU. Full length 15min film. Note that
the bladder is well opacified. The whole of the
right ureter and part of the left ureter are seen.
Often, only a portion of the ureter is visualized
owing to peristalsis emptying certain sections.
The bladder outline is reasonably smooth. The
roof of the bladder shows a shallow indentation
from the uterus.
Large calcified calculus in the
pelvis of the kidney obscured by
contrast medium. Since the
contrast medium and the
calculus have the same
radiographic density, the
calculus is hidden by the
contrast medium.
Renal mass. A
renal cyst (arrows)
has caused a bulge
on the lateral
aspect of the
kidney with
splaying of the
calices.
The calices.
(a) Normal calices. Each calix is 'cup-shaped',
(b) Many of the calices are clubbed. There is scarring of the parenchyma of
the upper half of the kidney indicating that the diagnosis is chronic
pyelonephritis,
(c) All the calices are dilated, the dilatation of the collecting system
extending down to the point of obstruction (arrow), in this case owing to a
malignant retroperitoneal lymph node
At ultrasound, the kidneys should be smooth in
outline. The parenchyma surrounds a central
echodense region, known as the central echo complex
(also called the renal sinus), consisting of the
pelvicaliceal system, together with surrounding fat
and renal blood vessels. In most instances, the normal
pelvicaliceal system is not separately visualized. The
renal cortex generates homogeneous echoes which are
less intense than those of the adjacent liver or spleen
and the renal pyramids are seen as triangular
sonolucent areas adjacent to the renal sinus. During
the first two months of life, cortical echoes are
Normal renal ultrasound
relatively more prominent and the renal pyramids are
strikingly sonolucent.
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
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 examined
in the distended state: the walls should be sharply defined and barely perceptible.
CT and MRI
Computed tomography is used for specific indications,
often after IVU or ultrasound have identified a problem.
Like ultrasound, CT can characterize masses and it shows
the retroperitoneal space.
It is an extremely sensitive method of detecting calculi and
I is also useful when assessing trauma or infarction. The technique is
virtually the same as for standard abdominal and pelvic CT, except that
sections of the kidneys are usually performed both before and after intravenous contrast medium has been given.
Magnetic resonance imaging gives similar information to CT, with a few
specific advantages, but it has several disadvantages and is only used in
selected circumstances, e.g. demonstrating renal artery stenosis and inferior
vena caval extension of renal tumours.
Normal CT
The basic principles of interpretation are the same as for IVU. The
renal parenchyma should have a smooth outline and opacify
uniformly after intravenous contrast administration, although early
images may show opacification of the cortex before medullary
opacification has had time to occur. The pelvicaliceal system should
show cupped calices with uniform width of renal parenchyma from
calix to renal edge, and the fat that surrounds the pelvicaliceal
system should be clearly visualized. The ureters are seen in crosssection as dots lying on the psoas muscles. They will not necessarily
be seen at all levels because peristalsis obliterates the lumen
intermittently. The bladder has a smooth outline contrasted against
the pelvic fat; its wall is thin and of reasonably uniform diameter.
Contrast opacification of the urine in the bladder is variable
depending on how much contrast has reached the bladder. The contrast medium is heavier than urine and therefore, the dependent
portion is usually more densely opacified.
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.
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
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
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
vena cava; K, kidney; P, pelvis; RV, renal vein; Sp, spine.
Radionuclide examination
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There are two main radionuclide
techniques for studying the kidneys:
The renogram which measures renal
function. Scans of renal morphology
(DMSA scan). The advent of CT and
ultrasound has reduced the need for
such scans. They are now used mainly
for evaluating renal scanning.
Renogram
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
camera.
The two agents of choice are "«Тс DTPA (diethylene triamine pentacetic acid) 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
glomeruli and secreted by the tubules.
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
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
progressive excretion and clearance of activity from the kidneys. Quantitative
assessment with a computer enables a renogram curve to be produced and the
relative function of each kidney calculated. The main indications for a renogram
are:
– measurement of relative renal function in each kidney this may help the surgeon decide between nephrectomy or
more conservative surgery;
– investigation of urinary tract obstruction, particularly
pelviureteric junction obstruction;
– investigation of renal transplants
The renogram curve. a)Vascular phase. b) Filtration phase, (c) Excretion
phase, (d)
Right kidney
4
Minutes after injection
12
Retrograde and antegrade pyelography
The techniques of retrograde and antegrade pyelography (the term pyelography
means demonstrating the pelvical-iceal system and ureters) involve direct injection of
contrast material into the pelvicaliceal system or ureters through catheters placed via
cystoscopy (retrograde pyelography) or percutaneously into the kidney via the loin
(antegrade pyelography). The indications are limited to those situations where 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
obstruction is required.
Plain film showing a calcified staghorn
calculus in each kidney.
Ultrasound of stone in right kidney. The stone (arrow)
appears as a bright echo. Note the acoustic shadow
behind the stone (double headed arrow).
Nephrocalcinosis. There are
numerous calcifications in the
pyramids of both kidneys (the left
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)
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
very dense nephrogram which is characteristic of acute ureteric obstruction,
(b) A film taken 23 h later shows opacification of the obstructed collecting
system down to the obstructing calculus (arrow).
Dilatation of the pelvicaliceal system, (a) Longitudinal ultrasound scan of right
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
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 arrow
points to a small amount of contrast pooling in a dependent calix. Note the normal
left ureter (horizontal arrow).
Renal pseudotumour (arrows) which
was subsequently shown to be normal
renal cortical tissue.
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)
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
thick septa within the mass, (d) Angiomyolipoma. This incidental finding
shows the typical appearance of a small echogenic mass (arrow).
Computed tomography (contrast-enhanced) in renal masses, (a) Cyst in left kidney
(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 carcinoma.
The mass (arrows) is not clearly demarcated from the adjacent kidney and shows
substantial enhancement. (c) Angiomyolipoma with a small mass (arrow) of fat
density.
Staging renal carcinoma, (a) CT scan showing
a large mass (M) in the left kidney from renal
cell carcinoma and a greatly enlarged lymph
node (arrows) in the left paraaortic area. This
node contained metastatic tumour cells, (b)
Coronal MRI scan showing a huge left renal
carcinoma (M) with tumour extending into the
inferior vena cava (IVC) via the left renal
vein. The caval extension of tumour (*)
extends to the top of the IVC. (c) Axial MRI
scan showing the IVC extension of tumour
(arrows). Normally, the IVC is seen as a signal
void.
Renal abscess, (a) Ultrasound scan
showing a complex mass (arrows)
in the right kidney, (b) CT scan in a
different patient showing
encapsulated fluid collection in the
lower pole of the right kidney
(arrows). D, diaphragm; L, liver; LK,
left kidney; RK, right kidney; Sp,
spleen.
Perinephric abscess. CT scan showing a rounded
loculation of fluid and gas in the left perinephric space
(arrows).
Renal trauma, (a) The lower pole of the kidney has been
ruptured and a pool of extravasated contrast can be
seen, (b) CT scan showing extensive haematoma
(arrows) surrounding a fragmented left kidney (K)
Horseshoe kidneys, (a) The two kidneys are fused at their lower poles.
The striking feature is the alteration in the axis of the kidneys: the lower
calices are closer to the spine than the upper calices. The kidneys are
rotated so that their pelves point forward and the lower calices point
medially. The medial aspects of the lower poles cannot be identified, (b)
CT scan of different patient, following i.v. contrast enhancement, showing
fusion of the lower poles of the kidneys. K, kidney.
Bladder neoplasm, (a) There is a large filling defect in the left side
of the bladder from a transitional cell carcinoma. Note the
obstructive dilatation of the left ureter, (b) Ultrasound scan from a
different patient showing a large tumour (T) within the bladder.
CT scan of carcinoma of bladder, showing an
extensive tumour (T) involving the bladder wall
but still confined to the bladder.
Bladder diverticula. Cystogram showing numerous
outpouchings from the bladder with a very large
diverticulum projecting to the left.
Prostatic enlargement. The bladder base is lifted up and shows an
impression from the enlarged prostate (arrows). The ureters are
tortuous and enter the bladder horizontally. A balloon catheter is
in the bladder.
Prostate carcinoma shown by
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 part of
bladder, shown on MRI scan (T1-weighted
sagittal section).
Small bowl
Anterior
abdominal
wall
Prostatic calcification. Numerous calculi just above the
pubic symphysis are present in the prostate.
Urethral stricture. An ascending urethrogram
showing a stricture in the penile urethra
(arrow). The patient had gonorrhoea.
MRI of seminoma (arrow) in right testis. The two testes
are well demonstrated. The high signal adjacent to both
testes is normal fluid between the layers of the tunica
vaginalis.
Normal uterus and vagina.
Longitudinal section. The central echo of uterus (U) corresponds
to the endometrial cavity; the uterus itself has a homogeneous echo
texture; V, vagina; B, bladder.
Normal ovaries (arrows).
Transverse section in 25-yearold woman. B, bladder.
Normal uterus, CT scan. B,
bladder; U, uterus.
Normal uterus, sagittal T2-weighted MRI scan.
There is a high signal from the endometrium (arrows).
B, bladder; V, vagina.
Ovarian cyst, (a) Longitudinal ultrasound scan to right of midline
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
ovary (arrows). Note the uniform water density centre of the cyst,
(c) Coronal T2-weighted MRI scan showing a left sided ovarian
cyst (arrows) in a patient with an enlarged uterus due to
adenomyosis. B, bladder; U, uterus.
Ovarian carcinoma, (a) Longitudinal ultrasound scan showing a very large
multilocular cystic tumour containing septa (S) and solid nodules (N). The lesion
was a cystadenocarcinoma. (b) CT scan showing large partly cystic, partly solid
ovarian carcinoma (arrows). The tumour, which contains irregular areas of
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
partly cystic tumour. The cystic component shows as a high signal on this T2weighted scan. B, bladder.