Transcript Imaging Diagnosis Of Parasitic Helminthes 2 Major Multi-System Diseases By Sh.Ghaffary January 2008 Major Multi-System Diseases Schistosomiasis Hydatid Disease Taeniasis, Cysticercosis Sparganosis Schistosomiasis Acute Schistosomiasis ( The Katayama Syndrome) • The chest.

Imaging Diagnosis Of Parasitic
Helminthes 2
Major Multi-System Diseases
By Sh.Ghaffary
January 2008
Major Multi-System Diseases
Schistosomiasis
Hydatid Disease
Taeniasis, Cysticercosis
Sparganosis
Schistosomiasis
Acute Schistosomiasis ( The Katayama Syndrome)
• The chest radiograph is either normal or shows
increased vascular and interstitial markings and
minimal enlargement of the hilar lymph nodes.
• Miliary tuberculosis in its early stages or a simple virus
infection may be suspected. The changes are not specific
(history and eosinophilia).
• The chest radiograph returns to normal with or
without treatment
Katayama stage of an acute
S. haematobium infection.
This young adult had not
previously been exposed to
schistosomiasis when he
bathed in a Central African
lake 4 weeks before this
radiograph. The chest
radiograph shows an
increase in vascular
markings with a faint
nodular pattern throughtout
both lungs; the hila are
prominent. There were no
focal lesions and the
findings were transient.
Schistosomiasis
Acute Schistosomiasis ( The Katayama Syndrome):
• In the abdomen there are three sonographic (and CT)
findings which contribute to the diagnosis of the
Katayama stage of acute schistosomiasis.
1. nonspecific hepatosplenomegaly. The left lobe of the
liver may be more enlarged than the right. liver is
sonographically homogeneous or, in a few cases,
hyperechoic.
2. At the same time there may be periportal and
juxtapancreatic lymphadenopathy, particularly in
children. The lymph nodes are sharply outlined and
round or oval, with a thin surrounding hypoechoic
halo.
Schistosomiasis
Acute Schistosomiasis ( The Katayama Syndrome):
3. Ultrasonography may also show multiple small
nodules throughout the liver parenchyma. These
nodules may persist in spite of adequate therapy: they
may be 4-5 mm in diameter and are well shown on CT
scanning, being hypodense with delayed contrast
enhancement.
(In subacute schistosomiasis, echogenic lesions in the liver are
thought to be due to portal vein branches (in cross-section). It
probably takes from 3 to 5 years to develop stage one periportal
(Symmers) fibrosis when patients have a high-intensity
infection. With low infection rates, it may take much longer.
There is no evidence of portal hypertension during the Katayama
stage. )
Schistosomiasis
Acute Schistosomiasis ( The Katayama Syndrome):
• The acute phase of S. japonicum infection results in
CNS involvement in about 2% of patients.
• CT scans of the brain may show edema around lowdensity inflammatory foci, which are often multiple and
contrast-enhancing with edema.
• In some cases there may be a mass effect , causing
shift with pressure on any part of the ventricular system.
(This pattern of CNS involvement must be distinguished from the
mass effect which is found in chronic cerebral schistosomiasis
affecting patients who have been previously and often repeatedly
infected.)
Chronic Schistosomiasis
Imaging changes other than in the acute state are
different with each type of infection and will be
discussed separately.
The clinical and laboratory investigations for each
patient depends on the symptoms.
Chronic Schistosomiasis
• All three major species of schistosome may affect the
kidneys.
• Infection with S. mansoni, S. japonicum, and S.
intercalatum particularly may affect the liver, causing
cirrhosis, portal hypertension, and splenomegaly. Espohageal
varices develop, with resulting hemorrhage, and pulmonary
hypertension may be an added complication.
• In S. haematobium infection, as well as urinary tract
involvement, there may be granulomatous disease of the
colon; the latter often occurs in conjunction with mucosal
polyps and causes diarrhea.
• In S. japonicum infection, the disease may affect the small
bowel as well as the colon, liver, and lungs; cerebral
infections may cause epilepsy.
Chronic Schistosomiasis
Schistosomiasis Haematobium:
• When there is hematuria caused by S. haematobium,
ultrasound and subsequently intravenous urography
may be indicated. Cystoscopy may show multiple
papillomas within the bladder.
• There is individual variation between populations,
even villages, seemingly infected with the same
schistosome to the same extent.
• Anyone working in a particular country or locality
must determine the effect of schistosomiasis in their
own patients, but it is possible to give a general review.
Chronic Schistosomiasis
Schistosomiasis Haematobium:
Ultrasonography
• In the urinary tract, ultrasonography can detect
hypertrophy of the bladder mucosa, thickening of the
bladder wall (which is normally less than 5 mm when the
bladder is distended), and bladder calcification.
• If the ureters are easily demonstrated by ultrasound, they
are probably thickened and abnormal; in some patients
calcification will be seen, but ultrasound is not a reliable
way to demonstrate early ureteric changes.
• Dilatation of the renal collecting system can be detected
very early, and represents the result of significant ureteric
dysfunction.
Chronic Schistosomiasis
Schistosomiasis Haematobium:
Radiography
• Plain radiography of the abdomen is of no assistance
until calcification has developed in the bladder and
ureters, although in severe infections calcified eggs may
also be seen in the soft tissues. ( Early calcification is
much more clearly seen by CT.)
• Intravenous (contrast) urography will provide very
useful diagnostic information. All the early findings will
be in the ureters and bladder; the kidneys remain
normal until later in the disease.
Chronic Schistosomiasis
Schistosomiasis Haematobium: Radiography
changes in the ureters
1. persistent filling of the lower segment in all films of the
urography series, not dilated or otherwise abnormal
2. Dilatation of the filled distal, intrapelvic segment
3. Earliest ureteric constriction is within the bladder wall
4. Changes in ureteric peristalsis
5. Ureter will have a ragged outline and a beaded internal
appearance, with some irregular dilatation because of acute
"pseudotubercles" in the submucosa.
6. As they heal these may cause strictures. In more
advanced cases there are multiple strictures, and gross
irregularity .
 Intravenous urograms of two African men. Kidneys are normal, but both
ureters are filled throughout their length and the lower thirds are
dilated, irregular, and show beading due to multiple intrinsic
constrictions. Their bladders do not show any calcification
C .In another patient there is narrowing of both ureters close to bladder and in the right
ureter there is a segment of dilatation between two areas of stenosis. D. Persisitent filling
in the lower half of both ureters, with a long constriction in the right ureter just above the
bladder.
B: marked dilatation of left ureter, showing
the typical narrowing as the ureter enters
the bladder wall. The right ureter is not
distended or even filled, so it may be normal
C: Ascending urography in another patient
shows stenosis of the distal segment of the
left ureter within the bladder wall and
marked dilatation above it.
Schistosomiasis
Schistosomiasis Haematobium:Radiography
Blader and renal changes
1. The bladder outline first becomes hazy and indistinct, due
to submucosal edema and pseudotubercles .
2. As the granulomas become fibrotic, the bladder wall shows
calcification, but the calcium is not within the fibrous tissue.
rather, it is entirely submucosal, in the eggs.
3. As the calcification spreads up the ureter, there will be a
matching reduction in the rate of peristalsis.
4. By the time there is hydronephrosis and hydroureter, renal
function is decreased with marked dilatation of the whole
system.
5. secondary infection will hasten these changes.
The ureters can calcify in schistosomiasis haematobium,
with (or, rarely, without) bladder calcification. Calcified
ureters may be narrowed or dilated
Gross bilateral hydronephrosis
and hydroureter demonstrated by
reflux from a retrograde
cystogram. The ureters are atonic
and have lost the beaded
appearance.
Extremely heavy bladder
calcifcation in
schistosomiasis
haematobium
The heavily calcified
(empty) bladder of an
Egyptian male patient.
Ultrasound scans showing gross
thickening of the bladder wall and of the
ureter
multi-layered calcification of the entire
bladder wall
Schistosomiasis
Schistosomiasis Haematobium:
Lungs
Radiological abnormalities in the chest are uncommon in
patients infected with S. haematobium
1. the Katayama syndrome.
2. reaction around the larvae. This is a local immune
reaction similar to others in the Loeffler syndrome.
There will be scattered hazy foci of consolidation in both
lungs, changing in both size and position at short
intervals, and without any specific distribution. There is
no lymphadenopathy .
3. The third pattern is often found by chance in the
elderly : a pattern of fine, generalized interstitial fibrosis,
distributed equally throughout both lungs.
late stage of
schistosomiasis . Both
lungs show marked
interstitial fibrosis and
there is enlargement of
the main pulmonary
arteries. Pulmonary
hypertension has many
causes and there is no
way to distinguish
schistosomiasis, nor, at
this stage, will specific
therapy have any effect.
Chronic Schistosomiasis
Schistosomiasis Haematobium: Colon
S. haematobium can
cause a
granulomatous
reaction in the large
bowel. A Superficial
ulceration and
edema causing
irregularity of the
right half of the
transverse colon
Rectal and colonic
calcification may
be seen
Chronic Schistosomiasis
Schistosomiasis Mansoni:
The main imaging findings in S. mansoni infections
reflect the pathological changes in the bowel, portal
system, and lungs.
Large Bowel
Changes follow as:
1) An edematous mucosal pattern with tiny ulcers leading
to spasm and incomplete distention .
there are many tiny
punctate mucosal
ulcerations, a
double contrast
barium enema will
show a fine granular
mucosa, as in this
hepatic flexure
Chronic Schistosomiasis
Schistosomiasis Mansoni
Large Bowel (continue)
2) loss of haustration, chiefly in the descending and
sigmoid colon, most marked in the distribution of the
inferior mesenteric artery.
3) heavier infection and chronic exposure leads to
multiple granulomatous polyps, usually 1-2 cm in
diameter, especially in the rectum, sigmoid and
descending colon.
4) Strictures may develop , and can be mistaken for
carcinoma or Crohn's disease.
5) Calcification in the eggs may be seen
Schistosomiasis
Mansoni
Schistosomal polyposis (arrows)
extending from the rectum to
the transverse colon (air-barium
enema).
Schistosomiasis Mansoni
A barium enema . a polypoid mass arising from the
left lateral rectal wall in the frontal view (E), more
clearly seen in the post evacuation film (F).
Schistosomiasis
Mansoni
This barium enema shows
stenosis of the rectum and a
stricture in the midsigmoid
colon. Throughout the
rectosigmoid there is loss of
haustral markings and the
bowel has become tubular
and rigid.
Schistosomiasis Mansoni: small bowel
S. mansoni does not commonly cause radiological changes in the small bowel .
All varieties of schistosomiasis can affect the duodenum; patients present clinically with
vague symptoms suggesting peptic ulceration. A) Marked deformity and narrowing of the
pylorus and duodenum. B )The edematous second and third parts of the duodenum
Chronic Schistosomiasis
Schistosomiasis Mansoni
Biliary Tract and Pancreas:
• Tubular and irregular calcification may be seen in the
main hepatic ducts, the common hepatic, cystic, and
common bile ducts, and also the pancreatic duct.
• There is seldom ductal obstruction.
• The tubular calcification may be seen on plain
radiographs , It is well shown by CT as calcified ring
densities or, depending on the section, parallel tubular
lines.
Schistosomiasis Mansoni: Biliary Tract and Pancreas
heavy calcification in the common hepatic
duct (arrows), cystic duct (open arrow), and
pancreas (curved arrows).
The CT scan showing dense calcification
in the neck of the gallbladder (arrows)
Chronic Schistosomiasis
Schistosomiasis japonica
• The radiological findings are different because eggs are
smaller and more in number.
• The S. japonicum worms live in mesenteric veins and
their eggs are deposited predominantly within small
bowel venules and in the mesentery.
Small Bowel:
• The mucosa of the duodenum and the upper jejunum
becomes edematous, coarse and irregular; motility is
decreased and there may be some dilatation. The
terminal ileum may show similar changes .
Schistosomiasis japonica: Small Bowel
Four views of the first
and second part of the
duodenum of a Chinese
patient with
schistsomiasis japonica.
Chronic Schistosomiasis
Schistosomiasis japonica
Colon and Rectum:
• Schistsoma japonicum infection produces changes very
similar to those seen in schistosomiasis mansoni.
Retroperitoneum
• Granulomas located in the retroperitoneal space may
become large enough to resemble malignant disease.
• Although CT, and occasionally ultrasound, can
demonstrate multiple eggs, the exact differential
diagnosis may only be possible by biopsy.
Chronic Schistosomiasis
Hepatic Schistosomiasis
Hepatomegaly and an often massive splenomegaly is
common wherever there is schistosomiasis.
Periportal fibrosis occurs in any type of schistosomiasis.
Changes in the liver :
thickening around the portal vein and its main
branche
2. when portal hypertension develops, there is usually
splenomegaly
3. multiple varicosities and collateral veins will develop.
1.
Chronic Schistosomiasis
Hepatic Schistosomiasis
• Schistosomiasis japonica may cause little clinical
evidence of liver damage .
• In schistosomiasis japonica the eggs are frequently
deposited along the fibrous septa of the liver with only a
mild inflammatory response. The eggs are more
common in the peripheral or subcapsular regions.
• The hepatic changes of schistosomiasis japonica are
characteristic .The background picture of periportal
fibrosis is similar to S. mansoni infections, but the extent
of hepatic calcification is quite different
periportal
fibrosis due to S.
mansoni
S. japonica
Nonenhanced
CT shows septal
calcification
close to the top
of the liver,
better seen with
contrast
enhancement
Nonenhanced CT scan of a 79-year-old
Japanese male with S. japonicum in his
stool.
Hydatid Disease
Hydatid cysts are classified into four types on the basis of
their appearance :
Type I: Simple Cyst with No Internal Architecture
Type II: Cyst with Daughter Cyst(s) and Matrix
Type III: Calcified Cyst
Type IV: Complicated HC
ultrasound, CT, or MRI provides the best images. All
methods of scanning can provide images in multiple planes
and no added contrast is necessary, except in CT imaging.
Used alone, or in combination, an almost 100% positive
diagnosis of hydatid disease can be made in the majority of
cases. Imaging may even provide a strong diagnostic
probability when immunodiagnosis is equivocal or even
(rarely) inaccurate.
Hydatid Disease
• Sonography should be the first method used to scan the
patient, with a chest radiograph added. sonography is highly
accurate (except in the chest, skeleton and CNS).
• CT and MRI often provide additional valuable information.
• Pulmonary lesions are usually detected on the chest
radiograph but, when it is available, CT is helpful
• Brain hydatids can be imaged by either CT or MRI
• Plain films are often adequate for imaging bone hydatids, but
CT and MRI yield more information as to extent of the lesion
and possible soft tissue involvement.
• Angiography, Doppler sonography and nuclear medicine are
only occasionally useful in the diagnosis of cystic hydatid
disease and are utilized only when the other modalities are
unavailable.
Hydatid Disease
Type I: Simple Cyst
appear as a well-defined anechoic mass with or without
hydatid sand and septa. Unilocular cysts are considered
to be an initial stage in the development of the parasite.
The pericyst is rarely identified by US and is seen by CT
only if it is calcified . However, it is demonstrable by
MRI, particularly on T2-weighted images which produce
a low intensity rim. Neither the cyst nor the pericyst
enhance by CT or MRI as they are avascular
Hydatid Disease
Type I: Simple Cyst
• At CT, a type I hydatid cyst appears as a well-defined, water-
attenuation mass. Frequently, the septa and cyst wall enhance
after injection of contrast material at CT and MRI, a finding that
helps differentiate type I hydatid cyst from a simple liver cyst.
• MRI features are also similar to those of a simple liver cyst and
include hypointensity on T1-weighted images and marked
hyperintensity on T2-weighted images.
• A low-signal-intensity rim ("rim sign"), which is more evident
on T2 MRI, has been described as characteristic of hydatidosis as
opposed to nonparasitic cysts in the liver and lungs. This finding
represents the parasitic membranes and pericyst. However, it is a
nonspecific finding that can also be seen in amebic abscess,
hepatocellular carcinoma, and hematoma.
Hydatid Disease
Type I lesions have a non-specific cystic appearance but if the
patient is rotated immediately before US scanning the settling
hydatid sand produces signals which have been likened to
falling snow
Ultrasound scan
reveals echos at
bottom of a liver
hydatid caused by
hydatid sand
(arrows).
Univesicular uncomplicated type I cyst
Type I: Simple Cyst Incidentally found type I HCs in a 45-year-old woman.
Computed tomographic (CT) scan shows multiple unilocular hypoattenuating
lesions in the liver (maximum lesion diameter, 15 mm) and spleen (maximum
lesion diameter, 30 mm).
MRI of a simple viable type I hydatid cyst of liver. (A) T1-weighted image (SE 733/20). Cyst
wall is isointense relative to cyst contents. (B) T2-weighted image (SE 2000/100). Cyst wall,
consisting of both intact parasitic membranes and pericyst, is of low signal intensity
compared with high signal of cyst contents.
Hydatid Disease
Large hypermature hydatid cyst filled with debris. Some detachment
of the cyst wall from the host pericyst is noted
Hydatid Disease
Type II: Cyst with Daughter Cyst(s) and Matrix
• Daughter cysts are seen inside the mother cyst.
floating membranes or vesicles can also be seen in the
cyst
• Sometimes multiple cysts and echogenic areas that are
enclosed together within a single capsule give rise to a
"racemose" or "wheel spoke" appearance.
• Consolidation of the daughter cysts may produce
echogenic solid lesions.
Type II lesions usually have a characteristic appearance
due to daughter cysts whether or not fluid or matrix
are present
Hydatid Disease
Type II: Cyst with Daughter Cyst(s) and Matrix
type II HCs can be visualized in three stages depending on
the age, number, and arrangement of the daughter cysts:
1. Type IIA lesions contain round daughter cysts arranged
at the periphery .
2. Type IIB lesions contain larger, irregularly shaped
daughter cysts that occupy almost the entire volume of the
mother cyst creating a "rosette" appearance
3. Type IIC lesions appear at CT as relatively highattenuation round or oval masses with scattered
calcifications and occasional daughter cysts. These
findings represent the degeneration of old cyst
Multivesicular type II hydatid with multiple daughter cysts giving a septated
appearance to the cyst
 Type II hepatic cyst with peripheral calcification. Multiple round
daughter cysts are seen peripherally within the lesion.
Old hypermature liver hydatid . Non-contrast CT shows calcification in the
cyst wall and matrix and fluid within the cyst, suggesting it is still evolving
and should be treated
Hydatid Disease
Type III: Calcified Cyst:
• Type III lesions are dead cysts with total calcification. They
demonstrate strong posterior shadowing at ultrasonography and
manifest as round, hyperattenuating areas at CT and hypointense
areas at MRI.
• Nonenhanced CT may show minimal or partial calcification of the
rim of hydatid cysts This is important, because a segmentally calcified
cyst may still harbor a living parasite and therefore may be infective.
Total rim calcification suggests degeneration and the parasite is
usually, but not invariably, dead (clinically, it can be observed rather
than actively treated.)
• Discovery of a type III lesion should provoke a search for uncalcified
type I and II cysts in the liver and other organs.
Hydatid Disease
Type III:
Calcified Cyst:
Chest CT-scan
demonstrating a
calcified hydatid
cyst on the dome
of the liver
Two hydatid liver cysts in a 75-year-old man. The larger pseudotumoral cyst has
some calcification in its wall while the smaller type III cyst is totally calcified on noncontrast CT.
Hydatid Disease
Type IV: Complicated hydatid cyst:
• Complications include rupture and superinfection and
may be seen in both type I and type II HCs.
• Contained rupture makes the detached endocyst
visible by all cross-sectional imaging methods. The
lesion does not become smaller.
• Communicating rupture also produces a characteristic
separation of endocyst from pericyst, and the cyst
becomes smaller.
Hydatid Disease
Type IV: Complicated hydatid cyst:
• If cyst ruptures in to the biliary track ERCP shows filling defects within
the biliary tree and may also reveal retrograde communication with the
cyst cavity. Biliary obstruction, if it occurs, may result in dilatation of
downstream ducts. occasionally daughter cysts or fragments of endocyst
may be seen in the biliary tree by US, CT or MRI.
• Cysts may also rupture directly into pleural and peritoneal cavities. If
air replaces some of the fluid in the pericyst cavity of lung lesions, the
air meniscus and water lily signs are produced on upright chest
radiographs
• Bacterial superinfection of HC is always secondary to rupture. Up to
25% of ruptured cysts may become infected. Numerous signs of cyst
infection have been described, including poor delimitation, mixed
internal echoes, and air-fluid or fluid-fluid levels. However, these signs
can also be seen in both intact HC and ruptured, uninfected HC.
Communicating rupture of a type I liver hydatid. CT scan shows partial rupture
through the slightly calcified anterior wall of the cyst into the surrounding
hepatic parenchyma. The "floating membrane sign" produced by detachment
of the germinal membranes of the endocyst is well demonstrated.
 Rupture of a type IV hepatic cyst into the biliary tree in a 48-year-old man who
presented with acute onset of jaundice and pain in the right upper quadrant. CT scan
reveals a nonenhancing mass with irregular contours
Air meniscus in a pulmonary
hydatid seen on CT cut.
The "sign of the double arch" or
"cyst-within-a-cyst" appearance
(arrows) in a ruptured
pulmonary hydatid. Once
rupture of the cyst begins, a large
opening may develop in the
membranes and the shrinking
cyst expels part or all of its fluid
into the communicating
bronchus. At this stage, air may
enter the endocyst, producing an
air-fluid level within the cyst
that may itself be capped with a
crescent of air between the
pericyst and endocyst. The wall
of the endocyst appears as an
arch above the air-fluid level and
the surrounding pericyst is
visible as a larger arch.
(A) MRI of liver hydatid with detached parasitic membranes on T-2 weighted image
producing the "snake or serpent sign". Both detached parasitic membranes and pericyst are
of low intensity. (B) MRI of another ruptured hepatic hydatid cyst showing the "snake or
serpent sign" of detached membranes within the endocyst. The cyst wall (black arrows) is
of low signal intensity relative to the cyst contents and the surrounding high-intensity host
reaction and edema (white arrows).
Hydatid Disease
Multisystem involvement
Hydatid disease can occur almost any where in the
body and demonstrates a variety of imaging features
that vary according to growth stage, associated
complications, and affected tissue. Radiologic findings
range from purely cystic lesions to a completely solid
appearance.
Hydatid disease in the lung
35 yr old farmer
presented with a one
week history of right
sided pleuritic chest
pain. Chest X-Ray
revealed:
A large 7cm cavity
occupying right middle
lobe. It contained fluid
and air with an
undulating, crenated
interface. There was
conslidation in the right
middle lobe. A diagnosis
of a ruptured hydatid
cyst was made.
Hydatid disease in the lung
water lilly sign : A 50 year old
man from the Middle East with
recent productive cough . There
is a cavity in the right mid-zone.
It has uniformly thick walls. The
walls of the cavity have partly
collapsed and are not under
tension from the surrounding
lung. There is a contained fluid
level
Hydatid cyst in kidney
Clinical presentation:Young adult male from the Middle-East with an abdominal mass. The
IVU shows a large soft-tissue mass expanding the lower pole of the right kidney. The right
pelvicalyceal system is tilted and displaced upward.
Type I HC of the brain
Axial CT scan shows a mass in
the left parietal lobe with an
attenuation similar to that of
cerebrospinal fluid. Note the
mass effect and the displacement
of the interhemispheric fissure
to the right. There is no edema
formation adjacent to the cyst.
Type IIB HC of the brain
HD with thyroid tissue involvement
Taeniasis saginata
• Taenia saginata is best diagnosed by stool
examination for eggs and proglottids, but radiologic
study may be of critical diagnostic importance when
stool examination is negative.
• Characteristically the tapeworm appears as a
single, gradually tapering ribbonlike filling defect in
the barium column within the ileum. While typically
attached to the jejunum, the proximal end is
generally not demonstrable because it is so narrow.
• The linear filling defect is usually continuous, but
discontinuities may be seen because only the wider
portions of the worm in profile will be recognized.
Taeniasis saginata
Radiologic distinction from
the more common
roundworm Ascaris
lumbricoides may be easily
accomplished.The
roundworm is cylindrical,
much shorter ( 1 5-30 cm),
and possesses an alimentary
tract which may appear as a
threadlike strand of barium
within the filling
Plain film showing tapeworm as
ribbonlike density (arrows)
within gas-containing ileal loop
Taeniasis saginata
• T. saginata is seldom demonstrated radiologically on
small bowel barium studies. Characteristically it appears
in the lower jejunum or ileum as an unusually long and
gradually widening radiolucent line within the barium
column .
• Unlike Ascaris, a tapeworm has no alimentary canal
and thus does not ingest barium.
Adult T. saginata in the ileum .Reflux of barium into the
terminal ileum during a barium enema revealed an Small bowel series . continuous
elongated ribbon-like radiolucent shadow representing
radiolucent structure running
the adult tapeworm, which was coiled upon itself through
through multiple loops of
part of its course.
jejunum and ileum
Cysticercosis (Outside the Central Nervous System)
• The calcified cysticercus produces single (rarely) or
multiple (often several hundred) calcifications in the
soft tissues, which are linear or oval in shape and usually
measure 4-10 mm or more in length and 2-5 mm in
width.
• The calcified cysts will have their long axes in the
plane of the surrounding muscle bundle
Cysticercosis . showing typical rice grain calcifications in the soft tissues and muscles of the
lower extremities.
Cysticercosis of the muscles of the
back, abdomen, buttocks, and
lower extremity . Note the
alignment of the calcified
cysticerci in the axes of the muscle
fibers and their variation in shape
from elongate and linear to more
plump oval or elliptical
configurations.
Cysticercosis involving the muscles of the neck, axillae, and chest wall
Neurocysticercosis
routine radiographs of the skull:
• About 10% of patients known to have cysticercosis
will show one or more cerebral calcifications.
• Over 75%, and in some series nearly 100%, will have
calcifications in muscles or elsewhere in the soft
tissues;
• In the brain, they occasionally show calcium
deposition in their investing capsules; there may be an
area of radiolucency inside and, in the very center, a tiny
calcified scolex may sometimes be seen on careful
inspection.
right lateral view of the skull reveal a
solitary calcified cysticercus in the right
frontal lobe
Neurocysticercosis
Neurocysticercosis
• CT and MRI performed before or after administration
of intravenous contrast media are the imaging methods
of choice in neurocysticercosis, giving reliable
information about the location and activity of the cysts.
• CT demonstrates : calcified and uncalcified cysts, freefloating cysts and hydrocephalus.
• MRI is of great value particularly in patients with
lesions at the base of the brain, temporal lobes, and
brain stem, as well as associated vascular insults. MRI is
superior in delineating brain edema.
Neurocysticercosis
In the CNS, the cysticercus, by way of the bloodstream,
initially invades the subarachnoid space and then the cortical
brain, especially at the junction of gray and white matter.
Radiological classification :
1) vesicular stage:
• Is the viable stage of the parasite and appears as a low-density
cyst on CT with minimal peripheral or no contrast
enhancement .
• On MRI, it appears as a hypointense lesion on the T1weighted image and hyperintense on T2-weighted.
Commonly, on MRI a central or mural nodule is identified
representing the scolex.
Single
cysticercus,
vesicular stage
MRI. A : Axial T1weighted, B : axial
T2-weighted,C:
coronal TI-weighted,
postcontrast, and D:
sagittal, postcontrast
images. Note scolex
within the cyst.
Neurocysticercosis
2) colloidal stage
• The cysticercal larva continues to undergo degeneration
into the colloidal stage, where the cyst enlarges, the
vesicular fluid turns dense, and the capsule becomes
thickened and lobulated .
• There may be a host inflammatory reaction with
formation of perilesional edema and peripheral contrast
enhancement.
CT Scan of the brain shows: Multiple cysts in vesicular,
(scolex inside the cyst are well identified) some cysts in
colloidal stage surrounded by perilesional edema, and
scanty calcified lesions on both cerebral hemisphere.
a)
b)
a)Post-contrast axial T1-weighted MRI showing a ring-enhancing cyst in the right parietal
lobe . b)Corresponding axial T2-weighted MRI shows a hypo-intense capsule (long arrow )
with anterior thickening, representing a scolex . The center of the lesion is hyperintense.
The adjacent brain edema is clearly depicted as a hyper-intense area (thick arrow)
ring enhancing lesions and vasogenic edema.
Neurocysticercosis
3) Calcified stage:
• The lesions are small and hyperdense on CT. This is the
sequela of nonviable granulomas commonly seen in
asymptomatic individuals.
• On MRI, small calcified lesions may be overlooked.
Scattered calcifications throughout the brain
Neurocysticercosis
Arachnoidal type:
• when there is meningeal involvement, an intense
inflammatory leptomeningeal reaction and fibrotic
thickening producing arachnoiditis occur.
• The cysticercus cysts are isodense or isointense to CSF
on CT and MRI respectively, and may be difficult to
detect if they are small.
• The diagnosis may be inferred by focal deformity of
the subarachnoid cisterns. Contrast enhancement of the
meninges and obstructive communicating
hydrocephalus may be seen on CT and MRI.
Neurocysticercosis
Intraventricular type:
• The cysticercus cyst may be found anywhere in the
ventricles, commonly in the midline leading to
obstructive hydrocephalus, either acute or chronic .
• The intraventricular lesions may be isodense or
isointense with CSF and there may be focal deformity of
the affected ventricle.
Intraventricular
Neurocysticercosis
Neurocysticercosis
Racemose type:
A conglomerate of vesicles appearing as multiloculated
cystic masses in the subarachnoid ,basal and sylvian
cisterns attaining large size, lacking scolices, and
producing significant compromise of the adjacent
structures.
Cysticercosis, racemose type. MRI coronal, multiple sections. T1-weighted, postcontrast
images.
Sparganosis
• Except in the CNS, imaging shows no specific findings.
• Calcification has occurred in some of the spargana
granulomas, and can be mistaken for cysticercosis.
• larger larvae could be recognized within a
subcutaneous nodule by ultrasonography.
• An uncommon clinical presentation is eosinophilic
urinary cystitis, with a localized mass (the granuloma
around the worm) that can be recognized on
ultrasonography, urography, or CT/MR scanning.
Sparganosis
• Worm granulomas have also occurred in the testes and
epididymis, presenting a difficult differential diagnosis
unless movement and change in position on rescanning
are recognized.
• Wherever the "mass" is recognized, its mobility helps
to establish the diagnosis (although sparganosis is not
the only parasitic infection in which the area of interest
moves around).
(A) Contrast-enhanced CT of the brain There is a 5-cm cystic lesion in the left occipital lobe
showing ring enhancement. (B) MRI of the same patient shows considerable bright edema
surrounding the cystic lesion.
Sparganosis
Gadolinium-enhanced MRI showing the tortuous linear, beaded granuloma