To spotlight on the techniques used for imaging as a diagnostic tool for parasitic diseases. To outline that imaging techniques can play an important role in diagnosis and management of Helminthic Infections. To illustrate the characteristic radiological findings of some Helminthic Infections.

1. RADIOGRAPHY OF HELMINTH
PARASITIC INFECTIONS:
DIAGNOSTIC APPROACH
D. Ibrahim Abouelasaad
MD Lecture
Main Parasitology

2. 1) To spotlight on the techniques used for imaging as a diagnostic tool for parasitic diseases.
2) To outline that imaging techniques can play an important role in diagnosis and
management of Helminthic Infections.
3) To illustrate the characteristic radiological findings of some Helminthic Infections.
Objectives

3. • Radiologists may unexpectedly face some of these parasitic diseases in their practice, hence it is
important to be familiar with some of its typical imaging findings.
• Imaging is also helpful to understand the basic physiopathology of the main human parasitic
diseases and remember their main clinical findings in order to achieve a correct diagnosis through
a good clinical-radiological correlation, which leads to a prompt and appropriate treatment of
these patients, hence the value of imaging.
• Imaging techniques especially X rays and Ultrasound, have been recommended in the Clinical
Practice Guidelines submitted by WHO for any curative program.
• Recently, the advanced equipment as Multislice CT & MRI and multidimensional US can provide
parasite imaging elsewhere in human body.
Clinical applications of imaging techniques in parasitic diseases:
1) Diagnosis of parasitic infections.
2) Assessment of pathology of parasitic infections.
3) Assessment of cure after treatment and follow up.
The diagnostic value of parasite imaging depends on:
1) The technique used for imaging.
2) Site of the parasite in human body.
Introduction

4. Sites of imaging
1) Abdomen & Pelvis:
a) Intestinal parasites.
b) Extra-intestinal parasites.
2) Chest:
a) Lung parasites.
b) Heart parasites.
c) Mediastinum parasites.
3) Soft Tissue and Bone Parasites
4) CNS.
Imaging Techniques includes:
1) Radiography a) X-rays.
b) Computed tomography (CT).
2) Magnetic resonance imaging (MRI).
3) Ultrasound imaging (US).

5. X-rays
Computed Tomography (CT)
 The two-dimensional (2D) imaging provides more clear images,
but some exams require a special dye (contrast) to helps the
radiologist see certain areas more clearly.
 Intravenous contrast agents are used to enhance organs and
visualize blood vessels. Oral contrast agents are used to
visualize the digestive tract.
 Computed tomography (CT) uses special x-ray equipment to make cross-sectional pictures.
 This technique provides tomographic images or slices of specific areas of the body from a large
series of two-dimensional X-ray images taken in different directions.
Advantages
1) X-ray can be carried out quickly and easily.
2) It provides benefit images in presence of suitable contrast media as:
Lung field, Bone, Intestinal gases, Calcified parasite in soft tissues, and
Induced contrast media as barium.
Disadvantages
1) the hazard of radiation exposure limits its use in some cases as pregnancy.
2) it is not useful for most abdominal parasitic diseases because of:
a) The one-dimensional imaging.
b) The unclear contrast media.

6. Disadvantages of Computed tomography:
 CT is highly technical, needs especial equipment and spend longer time in comparison with
plain x ray.
 CT scans deliver a relatively high dose of radiation to the patient. While this is not usually a
problem for a single scan, patients who need to undergo repeated tests can be subjected to
a significant level of radiation, increasing their cancer risk.
 Patients who undergo a CT scan often receive a dose of what’s known as a “contrast
material,” containing iodine. This allows specific areas of the body to be highlighted on the
scan. Some people can have an allergic reaction to this.
※Magnetic resonance imaging (MRI) is a medical imaging technique
using signals produced by resonance of nucleus in magnetic fi elds
to reconstruct images of human body. In recent years, MRI has
been developing rapidly and improving greatly, with capabilities of
examining all body systems and worldwide application.
※MRI is in general more safe technique in comparison CT, since MRI
does not use any ionizing radiation.
※MRI is highly technical, needs especial equipment and spend
longer time in comparison CT.
Magnetic resonance imaging (MRI)

7. Ultrasonography
Ultrasound-based diagnostic imaging technique used for visualizing internal
body structures including tendons, muscles, joints, vessels and internal
organs
Advantages:
• It allows easy and proper adjustment of the view, consequently, can
provides proper imaging.
• It is portable and can be brought to a sick patient's bedside.
• It is substantially lower in cost.
• It is safe as it does not use harmful ionizing radiation.
Disadvantages:
o Difficult imaging structures behind bone.
o its relative dependence on a skilled operator.
Ultrasound images are available today, with higher resolutions, allowing physicians to see much clearer
definition. During the last 20 years, newer technologies are set to improve the practical uses of ultrasound as,
o Color Doppler US for imaging blood vessels and blood flow.
o Echocardiogram used to examine the heart.
o Endoscopic US for imaging through intestinal lumen.
o Ultrasound Elastography (FibroScan): measures the stiffness of the liver to quantify liver fibrosis.

8. Abdomen &
Pelvis
Radiography
for Helminthic
Diseases

9. Abdomen & Pelvis Radiography for helminthic diseases
Intestinal helminthic diseases
o Parasites with lengths of centimeters and inhabiting the intestinal lumen can be imaged by the
various techniques ( as Ascaris and Taenia).
o Extra-intestinal complications of these parasites can be also diagnosed by various imaging
techniques.
Radiography may be useful in diagnosis of some intestinal parasites or their complications,
especially when:
1) X ray is employed in the upright position to look for fluid levels and gases in cases of intestinal
obstruction.
2) Oral and/or rectal contrast may be used to allows visualization of the digestive tract and the
intestinal parasites. The contrast may be:
• Dilute suspension of barium sulfate
• Iodinated contrast agents
• Rectally administered gas (air or carbon dioxide) or fluid (water) for a colon study, or oral
water for a stomach study.
Intestinal Parasitic Diseases Extra-intestinal Parasitic Diseases
• Ascariasis
• Taeniasis
• Schistosomiasis
• Hydatid disease
• Fascioliasis
• Migrating Ascaris
• Toxocariasis
• Paragonimiasis

10. Ascariasis
Plain X ray film showing a round-worm-like structure
which was outlined by gas within the lumen of a small
intestinal loop.
Mildly dilated small bowel loops without air-fluid levels
is seen.
Child supine view showing cluster of Ascaris worms in a
contrast of gases in the right mid-abdomen

11. Erect view of the same child showing numerous air-
fluid levels signifying mechanical obstruction.
Plain X ray film:
showing multiple air fluid levels (blue arrow heads)
and cigar bundle appearance in ileo-cecal area
caused by Ascaris worm bolus (red arrow).
Ascariasis

12. On using barium as contrast, Ascaris worms may
appear as a filling defect.
X ray after Barium meal: Ascaris within the
jejunum, seen as elongated filling defect (red
arrows)
Ascariasis
X ray after barium meal:
shows the small bowel. The worms are the black lines
within the contrast. In this case they are all arranged
tidily in the long axis of the bowel.
The worm ingests barium, and the barium may be seen
as a thin line of contrast in the center of the worm.
Especially after the remainder of the barium exits the
small bowel.

13. X ray after Barium Enema: There are serpiginous
filling defects in the ilium (red arrows)
representing adult roundworms
X ray after Barium meal:
Ascaris in the stomach and proximal small
intestine.
Ascariasis

14. Enhanced (barium meal) axial CT scan on abdomen: Note the linear and rounded
cut sections of Ascaris worm.
Ascariasis

15. X ray after Barium Meal: Showing Taenia
saginata worm of, outlined by barium as a
continuous radiolucent structure running
through multiple loops of jejunum and
ileum
Taeniasis
Only the outline can be seen, as the adult
tapeworm does not have a gut, and
therefore cannot swallow barium as
Ascaris.

16. Taeniasis
X-ray film after barium meal, the tapeworm (red arrows) was
detected as a long, translucent filling defect in the ileum.

17. X ray after Barium Enema:
Reflux of barium into the terminal ileum
during a barium enema examination
revealed a markedly elongated ribbon-like
radiolucent shadow representing the adult
tapeworm.
Taeniasis

18. Taeniasis
Enhanced (barium meal) axial CT scan on abdomen: Taenia Saginata small bowel
infestation.

19. Abdomen & Pelvis
Extra-intestinal Parasitic Diseases
• Schistosomiasis
• Hydatid disease
• Fascioliasis
• Migrating Ascaris
• Toxocariasis
• Paragonimiasis

20. Plain x-ray of the abdomen shows extensive
splenomegaly (red arrows).
In schistosomiasis, imaging techniques are useful in diagnosis of some characteristic
pathological lesions and complications.
Schistosomiasis mansoni

21. Extensive granulomas and polyposis of the
colon and rectum.
Stenosis of the rectum and a stricture in
the mid-sigmoid colon. There is loss of
haustral markings and the bowel has
become tubular and rigid.
Schistosomiasis mansoni

22. Schistosomiasis mansoni
Schistosomal
calcification
Plain radiographs shows linear pattern of calcification which is seen through a urine-filled bladder
(b) which also has mural calcification. The ureters (u) are also calcified. The rectum (R) is
distended with gas and feces with laminar pattern of calcification .

23. Schistosomiasis mansoni
Abdominal CT shows colonic
wall thickenings
accompanied by mural and
mesenteric venous
calcifications in the
ascending colon (arrows).

24. CT scan showing hepatic fibrosis in a patient with chronic Schistosomiasis
japonicum. Note the characteristic reticular pattern.
Schistosoma japonicum

25. Schistosomiasis haematobium
Plain X ray abdomen showing a rim of
calcification around the whole bladder (red
arrows) resembling a foetus head in the pelvis,
and of both ureters (blue arrows) due to the
dead calcified schistosome eggs.
Bladder and ureteric calcification are characteristics

26. IVP showing hydronephrosis (red arrows)
and hydroureter (blue arrows) due to
Schistosoma haematobium infection.
Schistosomiasis haematobium
Ascending urography showing stenosis of the distal
segment of the left ureter within the bladder wall and
marked dilatation above it.

27. X-ray of urinary bladder
shows several bladder calculi.
Axial CT images showing stone
urinary bladder
Schistosomiasis haematobium

28. The cystography appearance of carcinoma of the bladder complicating
S. haematobium (soft tissue shadow).
Schistosomiasis haematobium

29. Coronal (C) & Axial (A) CT images showing dense, extensive calcification of the urinary bladder
(Red arrow) due to the dead calcified Schistosoma eggs in the bladder wall.
Schistosomiasis haematobium

30. Coronal (C) & Axial (A) CT scan demonstrating a bladder cancer as a 'filling defect' in the
bladder (red arrows).
Diagnosis: Squamous cell carcinoma of the urinary bladder on top of schistosomiasis
(histopathology proved).
Schistosomiasis haematobium

31. Hydatid disease
Plain x-ray abdomen showing large calcified
unilocular hydatid cyst in the liver. Such a
cyst is not harmless because it could still be
viable and could rupture.
Plain x-ray abdomen cannot detect hydatid cyst, except when calcified.
Chronic hydatid cysts can calcify when the larvae die but sometimes calcified cysts can still have alive
larvae.

32. The cyst shows a partial collapse with slightly compressed, irregular margins and calcification
throughout the wall.
Such a cyst is harmless because it is not viable and couldn't rupture.
Hydatid disease
Plain x-ray abdomen showing an
hepatic calcified hydatid cyst (red
arrow).

33. Due to the risk of the spontaneous rupture, splenectomy is the primary treatment in such cases which
aims at eradicating the disease while decreasing the chances of cyst rupture.
Hydatid disease
Plain x-ray abdomen showing a large
circular calcified lesion in the left
upper abdomen, most consistent
with a calcified splenic cyst. Plain x-ray abdomen showing large ovoid calcified lesion
within the abdomen! Looks like an ostrich egg. It is most
likely a retroprotenial hydatid cyst.

34. Axial enhanced CT scan showing a
multivesicular hydatid cyst. Note the typical
peripheral location of the daughter vesicles
within the mother cyst (red arrows).
Hydatid disease
Unenhanced CT scan of the upper abdomen shows a
large unilocular hydatid cyst with a high-attenuation
wall in the subdiaphragmatic portion of the liver (red
arrows).

35. Axial (A) and coronal (C) CT views showing a calcified hepatic hydatid cyst (Red arrow)
with transdiaphragmatic migration to the lung (Green arrow).
Hydatid disease

36. Axial enhanced CT scan showing calcified
splenic hydrated cyst.
Hydatid disease
CT plain scan demonstrated round like cystic
lesion in the right liver lobe, with well-defined
boundary and even internal density. Several
daughter cysts were revealed, with ring shape
calcification in the wall of some daughter cysts.

37. Enhanced CT showing renal hydatid cyst with heterogenous content. Note the peripheral calcification
of the cyst (red arrow).
Hydatid disease
Differentiated from the simple benign renal cysts by??
performed percutaneous aspiration of the cyst under ultrasound guidance.
The benign renal cyst contained clear fluid. Microscopic examination revealed a
hypocellular smear composed of a few PMNs in a proteinaceous background with no
scolices or hooklets in the aspirated fluid.

38. Hydatid
disease
• ( a ) CT scan demonstrated a huge cystic lesion in the liver,
with detached internal cyst in a ribbon sign. ( b) MRI
demonstrated uneven signal in the cyst, detached internal and
external cysts, and floating of ruptured internal cyst in the cystic
cavity in a ribbon sign.

39. Imaging techniques for
Fasciola Infection
Ultrasonography
Ultrasonography may reveal hypodense/hypoechoic
lesions in the liver that correspond to the burrow tracks of
the larvae. Ultrasonography may reveal the adult fluke in a
bile duct or the gallbladder. Ultrasonography rarely reveals
scant ascites.
CT scanning
CT scanning may reveal multiple lesions that
measure 1-10 mm or tunnels in the liver
parenchyma. A radiating pattern of tunnels is
diagnostic. CT scanning may also reveal an adult
fluke in a bile duct or the gallbladder.
Findings of the ultrasound and CT scan can
sometimes be confused with alternate diagnosis
such as malignancy and stones.
MRI
MRI may suggest granulomata of the
liver parenchyma and may provide
findings similar to CT scanning.
Cholangiography
ERCP is considered the gold
standard technique of imaging
of the biliary tract in patients
with chronic phase of
infection. It also aids in
management of the fascioliasis
with ERCP guided
sphincterotomy and removal
of adult flukes in chronic cases
with obstructions of bile duct.

40. • US shows multiple small subcapsular,
confluent, ill-defined hypoechoic
nodules
Hepatic phase
fascioliasis
• CT shows Multiple, confluent,
hypodense, nonenhancing lesions
smaller than 2 cm in diameter.

41. Abdominal computerized tomographic examination shows
A: Tubular branching lesions in the right (arrow).
B: sub-capsular low-density area surrounded by a rim of parenchyma (arrow).
Hepatic phase fascioliasis
A B

42. Biliary phase
fascioliasis
• US demonstrates a linear echogenic material with no
acoustic shadowing (arrow) within the dilated
common hepatic duct representing a dead F.
hepatica worm.
• US demonstrates floating echo (arrows) with no
acoustic shadowing in the gallbladder
representing lived F. hepatica worm.

43. • MR image shows mild dilatation of
the common bile duct, and a filling
defect representing worms (arrow).
Biliary phase fascioliasis
• CT scans demonstrates dilated biliary
ducts with periportal tracking

44. Endoscopic Retrograde Cholangiopancreatogram (Ercp) x-ray showing Ascaris
into common bile duct and dilated CBD and intra-hepatic ducts
Migrating Ascaris

45. MRI revealed hypointense dot type signal in center
of CBD in axial imaging
Magnetic resonance cholangi-pancreatography revealed typical linear signals in common
bile duct, which appears like Ascaris lumbricoides.
MRCP single shot shows linear signal
of ascariasis in CBD
Migrating Ascaris

46. Toxocariasis
Liver CT scan showing a low-density area (red circled) due to toxocariasis.
Medical imaging can be used to detect and localize granulomatous lesions due
to Toxocara larvae. It is not specific but may help diagnosis when correlated with
the clinical aspect and laboratory investigations.

47. Toxocara canis-associated visceral
larva migrans of the liver
At the initial evaluation, there were multiple oval- or
irregular-shaped low-attenuating nodules scattered
along the portal veins. They were dominantly
located in the subcapsular area. Hepatobiliary phase
sequence of the enhanced MRI using hepatocyte-
specific agent
6 months after the treatment, the lesions had
almost disappeared and only a few scars were
persistent. Hepatobiliary phase sequence of the
enhanced MRI

48. • Abdominal paragonimiasis in a 49-year-old man with hepatic lesions
incidentally found during laparoscopic cholecystectomy. (a) CT scan shows
multilocular cystic lesions in the right lobe of the liver. (b) CT scan shows
multifocal ill-defined cystic lesions and several nodules (arrow) in the
omentum on the right side of the abdomen. These appearances are
suggestive of multilobulate parasitic abscesses in the liver with peritoneal
seeding of parasitic granulomas.
Abdominal Paragonimiasis
• Biopsy of the liver and
omentum demonstrated
paragonimiasis

49. Abdominal
Paragonimiasis
Laparoscopic surgery was performed. In addition to the mass-like structure in the greater
omentum numerous white nodules were found on the peritoneum. Pathological
examination showed granulomatous inflammation around parasite eggs

50. Intestinal
Anisakiasis