Chapter 30 - Mesenteric Small Bowel (CHERI NOTES) Flashcards
TRUE OR FALSE. Disease of the mesenteric small intestine is relatively rare. (p.765)
TRUE - A detailed radiographic study of the small bowel is justified only when the clinical suspicion of small bowel disease is high.
4 major symptoms of small bowel disease. (p.765)
- Colic
- Diarrhea
- Malabsorption
- Bleeding
___ is defined as recurrent and spasmodic abdominal pain with periods of relief every 2 to 3 minutes. (p.765)
COLIC
TRUE OR FALSE. Diarrhea caused by small bowel disease is less urgent than that caused by colon disease. (p.765)
TRUE
____ is manifest by steatorrhea; foul-smelling stools and weight loss. (p.765)
MALABSORPTION
_____ is the traditional method for radiographic examination of the small bowel tracked onto a standard upper GI (UGI) series.
(p.765)
SMALL BOWEL FOLLOW-THROUGH (SBFT)
- patient is asked to continue drinking
barium while a series of supine abdominal
films are obtained until the terminal ileum
and cecum are filled with barium.
Fluoroscopic examination is then performed. - Visualization of the distal ileum may be improved
with a double-contrast technique by insufflating
the colon with aire (SFBT with peroral pneumocolon)
__________ is a more sensitive fluoroscopic method for detailed small bowel examination. (p.765)
- The study may be performed single contrast using approx. 600 mL of barium or double contrast
using 200 mL of barium followed by 1000ML of methylcellulose to advance the barium and distend
the bowel.
ENTEROCLYSIS or the SMALL BOWEL ENEMA
- this study provides more uniform distension of the bowel;
even distribution of barium; superior anatomic detail and
shorter overall examination time. - the study is performed by passing a specially designed
12 to 14 French enteroclysis catheter through the mouth
or nose and into the distal duodenum or proximal jejunum. - guidewire is used for directional control of the catheter
during manipulation under fluoroscopy
TRUE OR FALSE.
The small bowel lumen and mucosal surface are best demonstrated by barium studies. (p.765)
TRUE
TRUE OR FALSE.
CT Enteroclysis improves upon barium enteroclysis by demonstrating the extraluminal component of bowel disease; the
mesentery; adjacent solid organs; the peritoneal cavity and the retroperitoneum. (p.765)
TRUE
- similar to enteroscopic enteroclysis; an 8 to 13 French
nasojejunal catheter is advanced beyond the ligament
of Treitz under fluoroscopic guidance. - 2L of enteric agent is infused at 100 to 150 cc/min under
fluoroscopic observation.
HIGH ATTENUATION CONTRAST AGENTS include ___ and _____. (p.765)
4% to 15% water-soluble iodinated contrast agents;
dilute barium solution
- glucagon or other antispasmodic agent is
administered intravenously.
- patient is moved to the table and an additional
500 to 1000 cc of enteric contrast is infused at the
same rate during CT scanning
- thin-slice MDCT allows for high resolution
reconstructions in axial; coronal and sagittal
planes.
LOW ATTENUATION ENTERIC AGENTS include ___ and ___. (p.765)
water; methylcellulose
CT enterography is performed in a manner similar to CT enteroclysis except the 1.5 to 2.0 L of enteric contrast
is given _____ instead of by enteric tuve injection. (p.765)
ORALLY
- CT enterography tend to have less reliable and less
complete distension of the small bowel but is easier
to perform and has higher patient acceptance.
BIPHASIC AGENTused in MR enteroclysis and MR enterography include ____ (give 4). (766)
low signal in T1WI and high signal intensity in T2WI
- water
- methylcellulose
- low-density barium
- polyethylene glycol
- spasmolytic agent reduce peristalsis and motion
artifacts - breath hold fast gradient echo sequences are
obtained in axial; sagittal and coronal planes - IV contrast maybe utilized to assess for
inflammatory hyperenhancement and tumor
vascularity.
_____ involves the use of a swallowable video capsule 26 mm long by 11 mm diameter and weighing 4 g. (p.766)
CAPSULE ENDOSCOPY
- capsule contains are video camera; four light-emitting
diodes as light source; a radiotransmitter and batteries - patients fast for 10 hours prior to ingesting the capsule.
- a sensor array is placed on the patient’s abdomen and
attached to a portable battery-powered recorder that
can worn around the waist. - capsule is swallowed and color video images recorded
at the rate of 2 per second up to approx. 50thousand
images over an 8-hour battery life span
TRUE OR FALSE.
Capsule endoscopy is able to visualize the entire small bowel mucosa and may detect mucosal lesions; ulceers and tumors
missed by imaging examinations. (p.766)
TRUE
- significant limitations include limited ability to localize
biopsy; or treat lesions and limited use in patients with
small bowel obstructions or strictures.
The mesenteric small intestine is a tube approximately ___ meters long that lies totally within the greater peritoneal cavity.
(p.767)
7 meters long
____ is arbritrarily defined as the proximal 2/5s of the mesenteric instestine. (p.767)
JEJUNUM
____ is the distal 3/5s of the mesenteric intestine. (p.767)
ILEUM
The jejunum and ileum are suspended from the posterior abdominal wall by the _____. (p.767)
SMALL BOWEL MESENTERY
- composed of connective tissue; blood vessels and lymphatic
vessels and is covered by peritoneum.; which reflects from the
posterior parietal peritoneum.
The root of the small bowel mesentery extends obliquely from the ligamentof treitz; just left of the __ vertebra; to the cecum;
near the right sacroiliac joint (p.767)
L2 vertebra
On CT; the ___ is defined by its normal vascular structures outlined by fat between loops of bowel. (p.767)
MESENTERY
- normal mesenteric lymph nodes may be seen as
soft tissue density nodules 5 mm or less in size. - the concave border of the small bowel loops is the
mesenteric border where the mesentery attaches.
The convex border; facing away from the mesentery
is called the ______. (p.767)
ANTIMESENTERIC BORDER
- identification of the border involved
by disease can be of diagnostic value.
On imaging studies; the _____ has a feathery mucosal patteren; more prominent valvulae conniventes; a wider lumen and
a thicker wall. (p.768)
JEJUNUM
The ____ has a less feathered mucosal pattern; thinner; less frequent folds; narrower lumen and a thinner wall. (p.768)
ILEUM
- has larger and more numerous lymphoid follicles
in the submucosa.
____ are finger-like projections that extend from the entire mucosal surface of the small bowel. (p.768)
VILLI
- they are composed of loose connective tissue
of the lamina propria - tiny capillareis and lymphatic vessels (lacteals)
extend to the submucosal vessels
TRUE OR FALSE.
The combination of valvulae conniventes and villi greatly expands the absoptive surface area of the small intestine. (p.768)
TRUE
The caliber of the normal small bowel lumen is less than __ cm in the jejunum tapering to less than __ cm in ileum. (p.768)
less than 3 cm;
less than 2 cm
Normal jejunal folds measure ____ mm thick; whereas normal ileum folds measure ____ mm thick. (p.768)
2 to 3 mm thick;
1 to 2 mm thick
Enteroclysis typically distends the normal jejunum to __ cm and normal ileum to __ cm; with folds appearing 1 mm thinner
in each portion of the mesenteric small bowel. (p.768)
4 cm; 3 cm
Normal lymph nodes seen in the mesentery are less than __ mm in diameter. (p.768)
4 mm
CT and MR enterography findings that suggest malignant small bowel lesions include____ (give 5). (p.768)
- Solitary lesions
- Nonpedunculated lesions
- Long segment lesions
- Presence of mesenteric
infiltration - presence of enlarged
mesenteric lymph nodes
(>1 cm short axis diameter)
____ tumors are the most common neoplasm of the small intestine; accounting for about one-third of all small bowel
tumors. (p.768)
CARCINOID TUMORS
- they are considered a low-grade malignancy that may recur locally or metastasize to the lymph nodes; liver or lung.
- arise from the endocrine
cells (enterochromaffin
or Kulchitsky cells) deep
in the mucosa. - these cells produce vasocative
substance including serotonin
bradykinins
About 20% of all carcinoid tumors arise in the small bowel; most commonly in the ____ where 30% are multiple. (p.768)
ILEUM
- only 7%; those with liver metastases; present with
carcinoid syndrome (cutaneous flushing; abdominal
cramps and diarrhea) because the liver inactivates
the vasoaactive substances. - the tumors grow slowly but cause a marked fibrotic
response of the bowel wall and mesentery because
the serotonin produced by the tumor induces an
intense local desmoplastic reaction. - complications include stricture; obstruction and
bowel infarction induced by fibrosis of the mesenteric
vessels.
TRUE OR FALSE.
CARCINOID TUMORS may be pedunculated and
cause intussusception. (p.768)
TRUE
- radiographic signs of fibrosis and metastases
resemble the findings of Crohn Disease and
overshadow the demonstration of the primary
tumor.
DIAGNOSIS? (Small intestines) Barium studies shows:
1. Luminal narrowing
2. Thickened and spiculated folds
3. Separation of bowel loops by mesenteric mass
4. Bowel loops drawn together by fibrosis
5. Primary lesion appearing as small (< 1.5 cm) mural
nodule or intraluminal polyp. (p.768)
CARCINOID TUMOR
DIAGNOSIS? (Small intestines) CT and MR findings of:
1. SUNBURST PATTERN of radiating soft-tissue density in the mesenteric fat due to mesenteric fibrosis.
2. Bowel wall thickening
3. Primary lesion appearing as a small; lobulated soft-tissue mass; occasionally with central calcification;
usually in the DISTAL ILEUM
4. Marked contrast enhancement of the primary tumor mass
5. Enlarged mesenteric nodes and liver masses due to metastatic disease. (p.768)
CARCINOID TUMOR
AdenoCA of the small bowel is about half as common as carcinoid tumor. (p.768)
It is most frequent in the _____ (50%) and __________ and is uncommon in the _____; where carcinoid is most common.
DUODENUM (50%); PROXIMAL JEJUNUM; DISTAL ILEUM (uncommon site)
- most patients are symptomatic at presentation
and 30% have a palpable mass.
3 patient conditions where there is increased risk for small bowel carcinoma. (p.768)
- ADULT CELIAC DISEASE
- CROHN DISEASE
- PEUTZ-JEGHERS SYNDROME
- complications include bleeding; obstruction
and intussusception - prognosis is poor with a 5-year survival of 20%
- metastatic spread is by intraperitoneal seeding;
lymphatic channels to regional nodes; and portal
veins to the liver. - morphologically; the tumor may be infiltrating
producing strictures; polypoid producing filling
defects; or ulcerating.
DIAGNOSIS? (small intestines) Barium studies typically show a characteristic “apple core” stricture of the small bowel. (p.768)
ADENOCARCINOMA OF THE SMALL BOWEL
DIAGNOSIS? (small intestines) CT and MR finding demonstrate: (p.768)
1. A solitary mass in the duodenum or jejunum (up to 8 cm in diameter)
2. An ulcerated lesion; or
3. An abrupt or irregular circumferential narrowing of the bowel lumen
with abrupt edges to the wall thickening.
ADENOCARCINOMA OF THE SMALL BOWEL
Lymphoma is responsible for about 20% of all small bowel malignant tumors. (p.769)
The ____ is the most common site for extranodal origin of lymphoma; and the ____ is most commonly involved.
GI tract; SMALL BOWEL
- most caes are non-Hodgkin Lymphoma
of B-cell type - Non-Hodgkin Lymphoma clinically involves
the GI tract in 30% of cases overall.
LYMPHOMA is most frequent in the __ ileum where the concentration of the lymphoid tissue is the greatest. (p.769)
DISTAL ILEUM
4 Morphologic patterns of involvement of Lymphoma (small intestines). (p.769)
- DIFFUSE INFILTRATION
- EXOPHYTIC MASS
- POLYPOID MASS
- MULTIPLE NODULES
- multiple sites of involvement are seen
in 10% to 15% of cases.
_____ is a feature of lymphoma (small intestines) due to the replacement of the muscularis and destruction of the
autonomic plexus by tumor without inducing fibrosis. (p.769)
ANEURYSMAL DILATION OF THE LUMEN
- as a result; obstruction is uncommon
DIAGNOSIS? (small intestines) Barium studies commonly reveal the following: (p.769)
1. Wall thickening with irregular; distorted folds due to the submucosal infiltration of cells.
2. Fold thickening may be smooth and regular in early stages due to lymphatic blockage in the mesentery.
3. Folds become effaced in later stages with greater cell infiltration into the bowel wall
4. Narrowed; widened or normal lumen
5. Cavitary lesions containing fluid and debris
6. Polypoid masses that may cause intussusception
7. Rare multiple filling defects that are larger than 4 mm; variable in size and non-uniform in
distribution.
- shallow ulceration is common
LYMPHOMA
DIAGNOSIS? (small intestines) CT demonstrates: (p.769)
- Circumferential wall thickening involving a long segment of small bowel
- Effacement of folds
- Mucosal nodularity
- Eccentric wall thickening
LYMPHOMA
TRUE OR FALSE.
EXOPHYTIC LYMPHOMA is generally of uniform soft-tissue density and enhances little; if any; with IV contrast
administration. (p.769)
TRUE
- This is a DIFFERENTIATING FINDING in
comparison with GI stromal tumors (GISTs) and
adenocarcinoma; which usually enhance
prominently. - CT and MR readily demonstrates associated
findings of lymphoma including mesenteric
and retroperitoneal adenopathy and
hepatosplenomegaly.
TRUE OR FALSE.
In lymphoma (small intestines); the mesentery may show a large confluent mass encasing multiple bowel loops or enlarged
individual nodes. (p.769)
TRUE
Radiologic sign which refers to the sparing of rind of fat surrounding mesenteric vessels that are encased by lymphomatous
nodes. (p.770)
SANDWICH SIGN
- mesenteric lymphoma
BURKITT LYMPHOMA in N.America usually presents with intestinal involvement; especially of the ___ area in children and
and young adults. (p.770)
ILEOCECAL AREA
- the malignancy is aggressive; with rapid
doubling time and poor prognosis; - imaging studies show bulky tumors
TRUE OR FALSE.
AIDS-related lymphoma is an aggressive high-grade non-hodgkin lymphoma with poor prognosis. (p.770)
- extranodal involvement; including small bowel lymphoma is common.
TRUE
- Adenopathy may be caused by lymphoma; Kaposi sarcoma or Mycobacterium avium- intracellulare infection. - The radiographic findings are identical to those seen in immunocompetent patients.
TRUE OR FALSE.
NODULAR LYMPHOID HYPERPLASIA may involve the entire small bowel. (p.770)
The condition is differentiated from lymphoma
by the uniform small size of the nodules
(2 to 4 mm) and even distribution through the
area of involvement.