2. Imaging of Small Bowel
Small Intestine is one of the most important organs for the immune
defense. Largest endocrine organ of the body.
Start from the pylorus and ends at the cecum.
Compared with the upper gastrointestinal tract and large bowel, the
small intestine is much less amenable to examination with
endoscopy, and as a result, radiologic investigations play a pivotal
role in the diagnosis of small-intestine pathology.
3. 3 Parts:
Duodenum(20cm), retroperitoneal
and supplied by the celiac artery
and SMA.
Jejunum(100 to 110 cm), Occupies
upper left of the abdomen , thicker
wall and wider then the ileum,
Mesentery has less fat and forms
only 1-2 arcades.
Ileum(150to160cm), Occupies the
lower right: Has more fat and forms
more arcades. Contain Peyer’s
patches. Ileum and jejunum and
supplied by the SMA.
7. Preferred initial radiographic investigation
Diagnostic in 50-60%
Radiographs done are
1.Supine Abdomen-bladder should be emptied before the film and film should inclu
2.Chest Radiograph- superior to erect abdomen to detect pneumoperitoneum
3.Erect Abdomen-air fluid level are seen .normal two may be seen at D-Jflexure an
Conventional Xrays
8.
9. Barium meal follow through
500 ml of 42%w/v barium
mixture is Ingested, fluroscopic
and over head radiographs at
15-30 minutes intervals,
continue till ileoceacal valve,
when barium has reached
caecum, with targeted
fluroscopy of special area of
interest.
10. Small bowel enteroclysis
The intubation and infusion of small bowel by barium,challenges the distensibility
Technique –infusion of 30-40%w/v at 60- 90mi/min after duodenal intubation.
Double contrast enteroclysis
infusion of 60- 95%w/v barium,followed by infusion of air/methyl cellulose to diste
11.
12.
13. Ultrasonography
Ultrasound of the small intestine requires high-frequency (5–17 MHz) linear array
Colour or power Doppler imaging and contrast-enhanced US (CEUS) - mural and
Advantages
1.cheap
2.quick
3.acceptable to patient
4.no ionising radiation-important in Crohn’s disease patient who may require man
5.extraluminal information
6.dynamic changes
14. Studies with of USG
• It shows bowel wall thickening,presence of mesenteric fat wrapping.These are us
• Other sign includes pattern of vascularisation,presence of free peritoneal fluid an
• Direct extra luminal information-presence of abscesseswhich may be missed wit
• Compared with small bowel follow through of the ileum,ileal bowel wall thickening
• Studies concentrated for use in crohn’s disease
15.
16. C T has central role in imaging abdomen
CT can depict bowel thickening,fistulas,abscesses and lymphadenopathy
Bowel wall assessment during different phases of scanning with i.v. contrast allow
Intramural gas may be detected
MDCT can reconstruct images in any angle
Advantages
1.quick
2.acceptable to most of the patient
3. major advantage is – provides extraluminal information over luminal contrast stu
CT
17.
18. CT ENTEROCLYSIS
Newer more specific technique for small bowel
Require same nasojejunal intubation and Small bowel distension with
contrast as barium enteroclysis
More quick
Ability to follow the progression of contrast is lacking.
CT ENTEROGRAPHY
• Small bowel is distended with orally ingested contrast as opposed to
that delievered by nasojejunal tube .
21. MR Imaging
Distinguish active disease with fibrosis
Definition of tissue planes is better than CT
Real time functional information may be obtained with MR fluroscopy and
this is a distinct advantage over CT
Gives extra luminal information and permit Multiplanar reformatting without ionis
Preferable in children and reproductive age
36. Congenital Anomalies of the Small Intestine.
Congenital abnormalities involving the small bowels are detected in neonates only
In a healthy neonate, air can usually be identified in the stomach within minutes of
Delayed passage of gas - traumatic delivery, septicemia, hypoglycemia, or brain da
43. Tumors of the Small Bowel.
Rare.
Usually single, but may be multiple particularly in certain syndromes
(i.e. intestinal polyposis syndrome). Tumors can be benign or
malignant.
Some benign tumors can progress and become malignant (i.e.
adenomas, leiomyomas)
Most are clinically silent for long periods; nearly half of all benign small
intestine tumors are found only incidentally either during an operation
or an investigation to visualize the intestine for other reasons.
Symptoms can be chronic and/or intermittent and include abdominal
pain, nausea, weight loss, bleeding and bowel obstruction.
44. Benign Tumors
Leiomyoma – Leiomyomas are tumors of one of the muscle layers of
the bowel wall. Some can grow into the lumen of the bowel and
become ulcerated and cause bleeding or anemia, which is the most
common symptom and finding.
46. Adenomas – Adenomas are benign tumors that do have
malignant potential. They cause symptoms due to blockage.
When they arise in the region of the papilla or the area of the
duodenum where the bile duct and pancreas drain they can
cause jaundice.
49. Lipomas are collections of fatty
tissue within the wall of the
intestine.
They are characterized by a soft
yellowish appearance when
viewed endoscopically.
These are completely benign
tumors with no malignant
potential. Lipomas do not need
to be removed unless they
become very large and cause
obstructive symptoms (or
bleeding due to ulceration).
50.
51.
52. Hemangiomas are collections of blood vessels that form a benign
vascular tumor in the wall of the stomach or intestine. They are
benign and sometimes found in conjunction with other syndromes
(i.e. Turners syndrome, Tuberous sclerosis, blue-rubber-bleb
syndrome and Osler-Weber-Rendu syndrome).
56. most desmoid tumors are well-circumscribed masses, although in some cases the
most are relatively homogeneously or focally hyperattenuating when compared to
The duodenum measures 20–30 cm in length. It forms an incomplete circle surrounding the head of the pan- creas and is described as having first, second, third and fourth parts.
The first (superior) part contains the duodenal cap or bulb and passes superiorly, posteriorly and to the right before turning down to become the second part. Posteriorly it is devoid of peritoneum. The second (descend- ing) portion passes down anterior to the right kidney and posterior to the transverse colon. Above and below the transverse colon it is covered with peritoneum. The duo- denum turns to the left and passes horizontally in front of the spine as the third (horizontal) part before it ascends in front and to the left of the aorta as the fourth (ascending) part to end at the duodenojejunal flexure (ligament of Treitz).
The small intestine measures approximately 5 m in length and extends from the duodenojejunal flexure to the ileocaecal valve. It is attached by its mesentery to the posterior abdominal wall and this allows it to be mobile. The proximal two-fifths constitute the jejunum and the distal three-fifths the ileum. The jejunum lies mainly in the left upper and lower quadrants and the ileum in the lower abdomen and the right iliac fossa. The jejunal and ileal branches of the superior mesenteric artery provide the blood supply.
trans abdominal
Ultrasound of thickened bowel. Relatively hypoechoic thick walls (arrowed) with echogenic lumen. Appearances are non-specific
CT enteroclysis. Adequate distension of the small bowel (SB) loops with clear delineation of the SB wall and valvulae conniventes
Coronal true FISP/ FIESTA MR image demonstrating small bowel at its entire length.
The use of an iso-osmotic water solution as an intraluminal contrast agent results in homogene- ous opacification of the bowel lumen. Note the increased con- spicuity of the normal bowel wall due to the high-resolution capability and total absence of motion.
Two-dimensional FLASH/SPGR coronal MR image with fat saturation, after IV administration of gadolinium and gluca- gon. Normal small bowel wall and valvulae conniventes are demonstrated with excellent conspicuity.
There is a focus of increased isotope uptake seen in the right lower quadrant and inferior to the iliac vessels on both the frontal and oblique views, most consistent with a Meckel's diverticulum.
Duodenal ulceration. The duodenal cap is deformed and a moderate-sized ulcer crater is outlined with barium.
Duodenography. A large diverticulum is demon- strated arising from the medial surface of the descending duo- denum. The filling defect corresponds to the ampulla of Vate
Lymphoid hyperplasia. Multiple small filling defects characteristic of lymphoid hyperplasia are shown on a double-contrast view of the duodenal cap.
Backwash ileitis" due to ulcerative colitis. Note features of chronic ulcerative
colitis in right colon, patulous ileocaecal valve, dilated distal ileum with granular mucosa.
Chronic ileocaecal tuberculosis. The caecum and ascending colon are retracted craniad and are fibrotic. scarred and saccilated (curved arrows). The terminal ileum in this patient is relatively patulous (straight arrows) and probably nodular. v=ileocaecal valve.
Jejunal diverticulosis on enteroclysis examination. Multiple moderate-sized and large diverticula present.
Acute small bowel ischaemia. Small bowel barium study shows partial functional obstruction, proximal to diffuse spastic narrowing of ileum with thickened folds and thick walls. There is a ''picket fence" pattern in places (arrowed). c=colon.
Small bowel ischaemia. Same patient as slide 33 CT after intravenous contrast. Note "target" sign in thickened ileal loops in right iliac fossa (arrowed), oedema in adjacent mesentery and fluid filled obstructed bowel to left of midline.
Aphthoid ulceration of terminal ileum (small arrows)- Note also "cobblestoning" (larger arrows).
a) Supine radiograph in a neonate with associated esophageal atresia shows three dilated loops of bowel.
(a) Upright radiograph shows multiple air-fluid levels occupying the entire abdominal cavity. (b) Image from a barium enema study shows numerous dilated, air-filled loops of bowel and a small, unused colon (functional microcolon).
Images from a contrast material-enhanced gastrointestinal examination show the small intestine on the right side of the abdomen and the colon and cecum on the left side. The ileum is seen crossing the midline from right to left (arrow)
Image from a contrast-enhanced upper gastrointestinal series clearly demonstrates the “corkscrew” appearance of the proximal small bowel (arrows) as it twists around the superior mesenteric artery
Abdominal CT scan shows the superior mesenteric vein (+) lying anterior to the superior mesenteric artery. The superior mesenteric vein normally lies on the right side of the superior mesenteric artery; in malrotation, it lies either in front or on the left side
(a) Image from a barium enema study shows extrinsic compression of the cecum by an extraluminal mass. (b) US image shows a cystic mass (C) that corresponds to a surgically proved duplication cyst. k = kidney.
in the pyloric segment of the stomach, there is a low attenuation polypoid intraluminal mass with well-defined margins and a smooth surface. Contrast enhancement is slightly heterogeneous, but no calcification, necrosis, or hemorrhage is seen. There is no evidence of extra-gastric invasion or gastric obstruction.
Barium study showing a well-defined lobular large adenoma.
Lipoma. (A) A large intraluminal filling defect is seen occupying and distending the second part of the duodenum on a barium examination. (B
CT shows the lesion to be a well-defined, round mass with low attenuation values, characteristic of fat.
Coronal and axial CT showing low density clearly delineated mass in duodenum/jejunum. Low intensity of the mass on MR T1 fat sat. Macroscopic image of lipoma.
Contrast material-enhanced CT scan of the abdomen demonstrates a mixed-attenuation, fairly
well circumscribed, lobutated mass (straight arrows) in the small intestine mesentery. The mass involves a loop of jejunum, which contains air and contrast material (curved arrows). C = air-filled colon. (b) Another CTscan obtained at a higher level shows the mass (black arrow), which is supplied by a large artery (white arrow) arising from the proximal superior mesenteric artery. K = kidney, L =
Neurogenic Tumors – Neurogenic tumors are benign growths arising from neural (nerve) tissue. The most common variety is neurofibroma. They are usually solitary. When multiple and found diffusely in the intestine they are more likely to be associated with neurofibromatosis. The diagnosis can be confirmed by their microscopic appearance after biopsy sampling.
Axial CT shows large clearly delineated mesenterial mass compressing the IVC, PA proven desmoid tumor
Hamartomatous and adenomatous
Adenomatous polyps and villous adenomas are two terms widely used to designate the growth pattern and gross morphology of adenomas. Adenomatous polyps are often symptomless. On barium studies they appear as small, smooth, round or oval intraluminal filling defects, and are often solitary and sessile. When multiple, they usually affect a single segment, are of different sizes and may be pedunculated. Villous adenomas are usually >3 cm in size
Hamartomatous polyps are a developmental anomaly and may be present in large numbers in the small intes- tine of patients with the Peutz–Jeghers syndrome. Recur- rent abdominal pain caused by intussusception is the most common clinical presentation. The polyps are shown on barium studies as multiple round or lobulated filling defects and are often pedunculated; intussuscep- tion is frequently demonstrated (Fig. 28-31) but this may also be seen with adenomatous polyp
