Lower Gastrointestinal System

A complete set of 100 practice flashcards covering the anatomy, procedures, pathology, and radiographic criteria of the lower gastrointestinal system as presented in Chapter 15.

Which structures of the alimentary canal are covered in Chapter 15?

Small intestine, Large intestine, and Anus.

What is the purpose of a Small Bowel Series?

Radiographic examination of the small intestine.

What type of contrast media is required for a Small Bowel Series?

Oral contrast media.

Which examination frequently follows an upper GI series?

Small bowel series.

What is the purpose of a Barium Enema (BE)?

Radiographic examination of the large intestine.

What materials are used in a double-contrast Barium Enema study?

Air and barium.

In which quadrants is the Duodenum located?

RUQ and LUQ.

In which quadrants is the Jejunum located?

LUQ and LLQ.

In which quadrants is the Ileum located?

RUQ, RLQ, and LLQ.

In which quadrant is the Ileocecal valve located?

RLQ.

What is the length of the Duodenum?

$10\,inches$ ($25\,cm$).

Which portion of the small intestine is described as having a 'coiled spring' or 'feathery appearance'?

Jejunum.

What fraction of the small intestine is made up by the Jejunum?

Two-fifths.

What fraction of the small intestine is made up by the Ileum?

Three-fifths.

Which segment of the small intestine has the smallest diameter and fewest indentations?

Ileum.

At what vertebral level is the Rectum located?

$S3$ level.

What are the three main differences between the large intestine and the small intestine?

Internal diameter, Haustra (taenia coli), and Relative location.

What color does air appear in a radiographic distribution study?

Black.

What color does barium appear in a radiographic distribution study?

White.

What are the primary functions of the Duodenum and Jejunum?

Digestion and Absorption (nutrient, $H_2O$, salts, proteins).

What percentage of $H_2O$ and salts is reabsorbed in the small intestine?

$95\%$.

What substances are produced by bacterial action in the large intestine?

Vitamins B and K, and Amino acids.

What is the primary function of the large intestine regarding waste?

Elimination (defecation).

What is the average measurement of an intact adult's small intestine?

$23\,feet$ or $7\,meters$.

What is the longest segment of the small intestine?

Ileum.

Are the terms 'large intestine' and 'colon' synonymous?

False.

What are the pouches or sacculations found along the mucosal wall of the large intestine called?

Haustra.

In which abdominal quadrant is the sigmoid colon primarily located?

LLQ.

Is the transverse colon an intraperitoneal or retroperitoneal structure?

Intraperitoneal.

In a prone double-contrast BE, which regions of the large intestine would be barium filled?

Ascending and descending colon.

Name five pathologic indications for a Small Bowel Series.

Enteritis, Meckel's diverticulum, Neoplasm, Malabsorption syndrome, and Ileus.

What is the radiographic appearance of Crohn's Disease?

'Cobblestone' appearance.

What are the two types of Ileus in the small bowel?

Mechanical and Adynamic (paralytic).

How does Giardiasis classically appear on a radiograph?

Dilated intestine with thick circular folds.

What radiographic sign indicates an Ileus of the small intestine?

Extended loops of small bowel.

What imaging modality is used for a Meckel's diverticulum study?

Nuclear medicine study.

List the four Small Bowel Procedures described.

1. Upper GI/small bowel combination, 2. Small bowel series alone, 3. Enteroclysis, 4. Intubation method.

What are three contraindications to using $BaSO_4$?

1. Presurgical patients, 2. Perforated hollow viscus, 3. Large intestine obstruction.

What are two contraindications to water-soluble iodinated contrast media?

1. Young or dehydrated patients, 2. Sensitivity to iodine.

When performing an Upper GI/Small Bowel combination, what is the first step?

Routine upper GI.

In a Small Bowel Only series, how much $BaSO_4$ is typically ingested?

$16\,ounces$.

What is the interval for radiographs in an Upper GI/Small Bowel combination?

$30\text{-minute}$ intervals and $1\text{-hour}$ intervals if needed.

What is Enteroclysis?

A double-contrast small bowel series.

Where is the catheter advanced to during an Enteroclysis procedure?

Duodenojejunal flexure.

What substances are instilled during Enteroclysis after the barium?

Air or methylcellulose.

What are the two types of Intubation procedures?

Therapeutic intubation and Diagnostic intubation (small bowel enema).

What is the NPO requirement for patient preparation in a small bowel series?

$8\,hours$.

What is the diet restriction for a small bowel series?

Low-residue diet for $48\,hours$.

What habits must the patient avoid before a lower GI exam?

Gum chewing and smoking.

List five pathologic indications for a Barium Enema.

Colitis, Diverticulosis/diverticulitis, Neoplasms, Volvulus, and Intussusception.

What are 'apple core' or 'napkin ring' lesions indicative of?

Neoplasms (Advanced carcinoma).

What can Volvulus lead to if not treated?

Necrosis.

What does CT Colonography identify with the use of air or gas?

Presence of small polyps.

What is the minimum NPO requirement for a Barium Enema?

$8\,hours$ (after midnight).

What is a cathartic?

A substance that produces frequent, soft or liquid bowel movements.

What are the two types of cathartics?

Irritant and Saline.

Name four contraindications to cathartics.

1. Gross bleeding, 2. Severe diarrhea, 3. Obstruction, 4. Inflammatory lesions.

What type of system is a standard barium enema kit?

Single-use, closed-system kit.

What hormone can be used as an optional drug if bowel spasm occurs during a BE?

Glucagon.

Describe the Sims' position used for enema tip insertion.

Left side, right leg flexed.

What is the initial direction of enema tip insertion toward?

Toward the umbilicus.

What is the maximum height the enema bag should be above the table?

$24\,inches$ ($60\,cm$).

What is a functional study of the anus and rectum during evacuation and rest phases called?

Evacuative proctography (defecography).

What are three clinical indications for a defecogram?

Rectoceles, Rectal intussusception, and Prolapse of rectum.

What type of barium is used for evacuative proctography?

High-density barium.

For a PA Projection of the small bowel at $15$ to $30\,minutes$, where is the CR directed?

$2\,inches$ ($5\,cm$) above the iliac crest.

Where is the CR directed for hourly radiographs during a small bowel series?

To the iliac crest.

What are the essential criteria for a PA projection of the small intestine?

Entire small intestine demonstrated, time interval markers visible, and optimal exposure factors.

Which projections are considered 'Basic' for a Barium Enema series?

PA and/or AP, RAO and LAO, LPO and/or RPO, Lateral rectum, R and L lateral decubitus, and PA post-evacuation.

Where is the CR directed for a standard PA/AP Barium Enema?

To the iliac crest.

What degree of rotation is used for an RAO Barium Enema?

$35^{\circ}-45^{\circ}$ oblique.

Where is the CR directed for an RAO Barium Enema?

To the iliac crest and $1\,inch$ ($2.5\,cm$) to the left of MSP.

Which structures are best demonstrated in an RAO Barium Enema?

Right colic flexure, ascending colon, and sigmoid colon.

Where is the CR directed for an LAO Barium Enema?

To the iliac crest and $1\,inch$ ($2.5\,cm$) to the right of MSP.

Which structures are open in an LAO Barium Enema?

Left colic flexure and descending colon.

What is the CR centering for LPO and RPO Barium Enema projections?

To the iliac crest and $1\,inch$ ($2.5\,cm$) lateral to the elevated side of MSP.

Which structures are visible in an LPO projection?

Right colic flexure, ascending, and rectosigmoid colon.

Which structures are visible in an RPO projection?

Left colic flexure and descending colon.

What is the CR level for a lateral rectum projection?

Level of the ASIS and midaxillary plane.

What does the lateral rectum projection specifically demonstrate?

The rectosigmoid region.

Where is the CR directed for Right and Left Lateral Decubitus projections of the large intestine?

To the iliac crest.

What are the special projections for a barium enema?

AP axial, AP axial oblique, PA axial, or PA axial oblique.

What is the CR angle and direction for an AP axial 'butterfly' projection?

$30^{\circ}-40^{\circ}$ cephalad.

What is the rotation angle for an LPO AP axial oblique projection?

Rotate $30^{\circ}-40^{\circ}$.

What is the CR angle and direction for PA axial and PA axial oblique projections?

$30^{\circ}-40^{\circ}$ caudad.

Where is the CR directed for a PA axial projection?

Level of ASIS and MSP.

What is the primary evaluation criterion for axial/axial oblique projections of the colon?

Elongation of the rectosigmoid colon.

What is the skin dose (Sk) for a Lateral Rectum projection in a review of patient doses?

$2629\,mR$.

What is another term for regional enteritis?

Crohn's disease.

Why is methylcellulose introduced during enteroclysis?

To dilate the loops of small intestine.

In what age group is intussusception most common?

Children younger than $2\,years$ of age.

What is the most common type of colon cancer?

Adenocarcinoma.

How should a patient with a latex allergy be treated regarding supplies?

They should NOT be exposed to natural latex; use latex-free alternatives (False to natural latex).

What is the recommended kV range when using a water-soluble contrast agent?

$80-90\,kV$.

What are the two phases of an evacuative proctography study?

Strain/evacuation and Post-evacuation.

What is a common pathologic indication for evacuative proctography?

Rectocele.

Which projection best demonstrates the rectum during an air-contrast barium enema?

Ventral decubitus.

What is the typical rotation for an RAO axial barium enema?

$35^{\circ}-45^{\circ}$.

What is the CR centering for a PA Post-evacuation film?

To the iliac crest.

What is the primary purpose of taking a scout radiograph before a small bowel only series?

To evaluate the abdomen before contrast administration.