Ch.17 Lesson 2 : Anatomy and Procedures of the small intestine Flashcards
Extends from pyloric sphincter to ileocecal valve
Small Intestine
How long is the average adult length of the small intestine
22 feet
Three portions of the Small Intestines:
Three portions:
*Duodenum
*Jejunum
*Illeum
Is 8 to 10 inches long and C shaped
Duodenum
What is the first portion of the duodenum called
Duodenal bulb
Portion that joins jejunum is a sharp curve called:
duodenojejunal flexure
What is supported by the suspensory muscle of the duodenum (ligament of Treitz)
Flexure
Functions of the small intestine:
Digestion and absorption of food
contraction waves by which the
digestive tube propels contents toward the
rectum
Peristalsis
Average transit time to ileocecal valve
2 to
3 hours
What is the most common contrast for the alimentary canal ?
Barium sulfate
but water soluable iodinated contrast media may also be used
Why are iodinated solutions not typically used for the alimentary canal ?
Iodinated solutions become diluted in the small intestines, so clear anatomic detail cannot be seen and it absorbs too quickly
Before beginning examination, the
radiographer should
*Describe the contrast media and administration
(i.e., taste, enema tip insertion).
* Inform the patient that the room will be darkened
during the procedure.
* Introduce the patient and fluoroscopist to each
other.
where is peristalsis greater in ?
*Peristalsis greatest in stomach and duodenum
* Slows in distal part of GI tract
What is peristalsis affected by :
body habitus,
pathology, use of narcotic pain medicine,
body position, and respiration
normal peristaltic activity
exposure time no longer than 0.2 seconds and never longer than 0.5 s
what do you want for your time and kvp
fast exposure
high kvp
how much time does hypermotility require
0.1 seconds or less
when are exposures made :
on expiration
Barium or other opaque contrast
administered one of three ways
Orally
Reflux filling via large-volume barium enema
Direct injection via a tube placed into the small
bowel, termed enteroclysis
What is the most common way that barium or other opaque contrast is given
Oral method most common
Patient Prep for Small Intestine
Examination
*Soft or low-residue diet for 2 days before
study
*Food and fluid withheld after evening meal on
day before examination
* Breakfast withheld on day of examination
* Cleansing enema for colon may be
administered
what two exams are timed
*IVU
*Small bowel
- Termed small bowel series because several
identical images are produced at timed
intervals - Each image identified with time marker
indicating interval since ingestion of barium - Images obtained with patient in either supine
or prone position*
Oral method of examination
Why is supine used for oral method of examination
To take advantage of superior and lateral shift of
stomach, which improves visualization of
duodenum and jejunum
To prevent compression of overlapping loops of
intestine
why is prone used for oral method of examination
To compress abdomen and increase image quality
When are the images usually taken for the oral method of examination
First image usually taken 15 minutes after
ingestion of barium
* Next interval varies between 15 and 30
minutes
* Radiologist inspects each image
* Varies procedures according to individual
*When barium reaches ileocecal region, uses
fluoroscopy to obtain compression radiographs
When is the oral method of examination complete
Examination complete when barium seen in
cecum
* Typically 2 hours after ingestion in patients with
normal motility
Essential projections for small intestine
PA or AP
Patient position for PA or AP small intestine
Supine or prone
Part position for PA or AP small intestine
Part position
MSP centered
For 30-minute interval, center IR at level of L2
For delayed images, center IR at iliac crests
Criteria for AP/PA small intestine
*Entire small intestine on each image
* Stomach on initial image
* Time marker
*Vertebral column centered
* Complete examination when barium reaches
cecum
