GI Tract Anatomy and Imaging Techniques

• Explores the anatomy, imaging techniques, and diagnostic procedures related to the gastrointestinal (GI) tract and accessory organs like the liver, gallbladder, and pancreas.

GI Tract Anatomy

• Upper GI includes the mouth, salivary glands, pharynx, esophagus, stomach, and small intestine-duodenum, proximal to the ligament of Treitz.
• Lower GI consists of the small intestine-jejunum & ileum (distal to the ligament of Treitz) and large intestine.
• Accessory organs are the liver, gallbladder, and pancreas.

X-Rays in GI Tract Imaging

• Plain films without contrast are a type of X-ray used.
• Acute abdominal series involves 2-3 views, including AP supine, PA upright, and PA chest if the patient can stand
• If the patient cannot stand, AP supine, left lateral decubitus, and AP spine chest views are taken.
• If the patient cannot stand or turn, AP supine, AP supine chest, and cross-table view (lateral) are used.
• KUB (kidneys, ureters, and bladder) X-rays do not necessarily show the diaphragm
• They are useful for looking for stones or issues in the kidneys, ureters, or bladder.
• Plain films with contrast include upper GI series and upper GI series with small bowel follow-through.
• Contrast X-rays include lower GI series (barium enema +/- air).

Acute Abdominal Series

• Assesses the entire GI tract, specifically looking for gas patterns and areas of potential obstruction.
• Technique depends on the patient's ability to stand or turn.
• If patient can stand, use AP supine, PA upright, and PA chest views
• If patient is unable to stand, use AP supine, left lateral decubitus, AP supine chest views
• If patient is unable to stand and unable to turn, use AP supine, AP supine chest, cross table view (lateral)

Kidneys, Ureters, and Bladder (KUB) Imaging

• Assesses the urogenital tract and specifically looks for calcifications.
• The technique used is the AP supine view.

Upper GI Series

• Indications include mechanical esophageal stricture concern, upper abdominal pain that may be gastric or duodenal, and surgical or duodenal procedure.
• Barium contrast is typically used
• Water-soluble contrast can be used if there is a concern for perforation
• The location of the area of concern dictates the images taken.

Upper GI Series with Small Bowel Follow-Through

• Used for further evaluation of strictures, obstruction, masses, and abnormal motility.
• Limitations include mild strictures and small masses.
• Can be obtained with or without an upper GI series.
• Images are taken every 15-30 minutes until the contrast reaches the terminal ileum.
• The process usually takes 30-120 minutes.

Lower GI Series

• Used to look for colonic strictures (position and length), colonic fistulas, and postoperative leaks after surgery.
• A rectal tube or barium enema is inserted, and contrast is given.
• Multiple images are taken to view all areas of the large intestine from the ileocecal valve to the rectum.

Interpretation of Abdominal X-rays

• Includes identity (patient identifiers like name and date of birth, and study identifiers like date of study) and quality (visibility of lateral edges and vertebrae, centered spinous processes, visualization from diaphragms to pubic symphysis).
• ABDO X components: A (air - intra and extraluminal), B (bowel - position and structure), D (dense stuff - bones and calcification), O (organs and soft tissues), E (external structures/artifacts).

Air Assessment in Abdominal X-Rays

• Intraluminal air is normally found in the stomach, small intestine, and large intestine, with a diffuse, irregular pattern.
• Abnormal intraluminal air presents as distended bowels and air-fluid levels.
• Extraluminal air is rarely normal, except shortly after abdominal surgery when air is used to inflate the abdomen or is introduced during open surgery.

Bowel Assessment

• Normal small bowel is located centrally within the abdomen, with folds running across the lumen's diameter and small air volume.
• Normal large bowel is located peripherally, with folds running part way across the lumen's diameter (haustral folds) and some air or fecal matter.
• Rule of 3-6-9: normal diameters are 3 cm for the small bowel, 6 cm for the large bowel, and 9 cm for the cecum.

Dense Structures, Organs, and Soft Tissues

• Bones assessed include ribs, vertebrae, pelvis, and femur.
• Calcifications may include stones, phleboliths, and vascular structures.
• Organs and soft tissues assessed include the liver, spleen, stomach, kidneys, and psoas muscles.

External Structures/Artifacts on X-rays

• Examples include bladder and NG tubes.

CT Scans of the GI Tract

• Indications include abdominal pain, ascites, jaundice, abnormal liver tests, and renal symptoms.
• Patients must be able to lie flat and still.
• Contrast protocol may be required, depending on the test ordered.
• Rendering options: abdomen only, pelvis only, or abdomen and pelvis.
• Contrast options: without, with oral only, or with IV only.
• Concerns include pregnancy (negative test required for females of childbearing age) and renal function (required if receiving IV iodinated contrast).

Ultrasound of the GI Tract

• Indications include abdominal pain, ascites, jaundice, abnormal liver tests, renal symptoms, and pregnancy.
• RUQ or complete ultrasounds require patients with a gallbladder to be NPO for 4 hours prior.
• Renal/bladder or pelvic ultrasounds need a full bladder.
• Visualization includes organs (liver, gallbladder, pancreas, kidneys/bladder, uterus/ovaries) and vasculature (aorta, renal arteries).
• Studies should be specific : complete abdominal, RUQ, renal, or renal artery US.
• Limitations include difficulty getting clear pictures in large patients and the need for additional studies.
• A good initial test is for patients when other studies may be contraindicated.

Upper GI Diagnostics

• Indications include nausea, vomiting, hematemesis, melena, anemia, non-cardiac chest pain, dysphagia, unexplained weight loss, and intractable cough.
• Assessment can include structural issues (ulcers, inflammation, varices, strictures, lesions/masses, abscesses, tears/ruptures) and functional issues (impaired motility, secretion, absorption).
• Diagnostic tools include X-rays (upper GI series), CT chest, EGD, modified barium swallow, FEES study, manometry, and pH monitoring.
• CT is seen the best on CT chest

Esophagus Diagnostics

• Indications include dysphagia, globus sensation, non-cardiac chest pain, and hematemesis/melena.
• Assessment includes structural issues.

X-Rays for Diagnosis

• Types include barium swallow (with fluoroscopy) and upper GI series (plain films at different time intervals, used to look for strictures, masses, and dilatation).

Esophagogastroduodenoscopy (EGD)

• An endoscope is inserted into the upper GI tract for direct visualization.
• Indications: Diagnostic for chronic upper abdominal pain, dysphagia, and iron deficiency anemia; Therapeutic for foreign body removal, dilation or stenting of strictures, esophageal variceal ligation, upper GI bleeding control, placement of feeding tubes, and management of achalasia.
• Contraindications: Absolute (perforated bowel, peritonitis, toxic megacolon); Relative (coagulation issues, increased risk of perforation, unstable patient).
• Complications: Sedation related (hypoxemia, hypotension, arrhythmias, aspiration) and Procedural (bleeding, infection, perforation).

Endoscopic Ultrasound (EUS)

• Ultrasound attachment on end of endoscope
• It can evaluate masses/lesions within the wall of the esophagus can assess other organs surrounding tissues.

Modified Barium Swallow (MBS)

• Fluoroscopy assesses swallow/peristalsis with barium liquids/solids.
• Indications: Dysphagia and suspected aspiration; Contraindications: Perforation and GI obstruction; Complications: N/V, hypersensitivity, and constipation/diarrhea.

Fiberoptic Endoscopic Evaluation of Swallowing (FEES)

• Fiberoptic scope in the nares allows evaluation of swallowing.
• Indications: Dysphagia, suspected aspiration, and patients who can't have MBS (pregnant or unable to travel to radiology).
• Contraindications: Inability to tolerate barium, severe agitation/movement disorder, severe bleeding disorders, recent epistaxis/nasal surgery, and bilateral obstruction of nasal passages.
• Complications: Vomiting, epistaxis, mucosal perforation, and laryngospasm.

Manometry

• A probe is inserted through the nares into the esophagus that has pressure sensors.
• Indications: Dysphagia, odynophagia, GERD, and non-cardiac chest pain.
• Contraindications/cautions: Recent esophageal/nasal trauma/surgery, significant epistaxis history, esophageal varices, and coagulation issues.
• Complications: Vomiting, epistaxis, and perforation.

Esophageal pH Monitoring

• A probe is inserted through the nares into the esophagus that contains pH sensors.
• Indications: GERD and non-cardiac chest pain.
• Contraindications/cautions: Recent esophageal/nasal trauma or surgery, significant epistaxis history, esophageal varices, and coagulation issues.
• Complications: Vomiting, epistaxis, and perforation.

Stomach Diagnostics

• Indications: Chronic N/V, hematemesis, melena, GERD, upper abdominal pain (typically epigastric/LUQ), non-cardiac chest pain, and abdominal bloating/distention.
• Assessment includes structural issues (X-ray, CT abdomen, EGD) and functional issues (gastric emptying study, manometry, pH monitoring).
• Labs: H. pylori and pathology.
• CT difficult to asses in stomach

Esophagogastroduodenoscopy (EGD) for Stomach Diagnostics

• Indications: Diagnostic for chronic upper abdominal pain and iron deficiency anemia.

Gastric Emptying Study

• NM study where radionucleotide tracer mixed with food
• It is conducted with images at set intervals.
• Functional: Suspected gastroparesis(early satiety, post-prandial N/V or abdominal pain) and GERD. .
• Cautions include allergy and Hyperglycemia in diabetes
• Complications include Allergic reaction to tracer and discomfort/nausea associate

Esophageal Manometry

• Functional procedure, a probe places through the nares and endoscopy to the duodenum
• Measurements taken at rest and small mea
• Indications: Gastric motility disorders, cardiac chest pian and GERD
• Cautions: Recent esophageal and nasal trauma
• Complications: Perforation

Lab Studies for gastric problems

• H. pylori: tests for a gram-rod bacteria, often acquired in childhood and colonizes gastric epithelium
• Non-invasive tests for H. Pylori: Urea breath test, stool test and serologic tests (most common)
• Invasive test for H. Pylori: CLO test and PCR test/culture

Duodenum Diagnostics

• Indications: Chronic N/V, hematemesis, melena, GERD, upper abdominal pain, non-cardiac chest pain, and abdominal bloating/distention.
• Assessment includes structural issues (X-ray, CT abdomen, EGD).

Lower GI Testing

• Indications: N/V, hematemesis, melena (with negative EGD), abdominal pain, weight loss, abdominal distention, diarrhea, flatulence, and abnormal imaging.
• Differential diagnosis includes structural issues (strictures, volvulus, intussusception, fistulas, masses, diverticular disease, inflammatory bowel disease, ulcers/lesions, hemorrhoids) and functional issues (malabsorption/maldigestion like Celiac disease, changes in motility like ileus) and infectious issues (Appendicitis, Bacteria, Colitis)

Small Intestine Disorders

• Celiac Disease, Obstruction, GI Bleed, Hernia
• Obstructions inclue Adhesions, Mass and interssussception
• GI bleed. and Ischemic Bowel are also factors

Small Interitis Diagnostics

• Imaging used when diagnostics

Small Bowel Follow Through

• Radiography and use of contrast to visualize the small bowel function

Lower GI Testing: Imaging

• CT, CT enterogrpahy
• Video capsule endoscopy (VCE)
• Lab studies: Malabsorption , fecalat and celiac Labs

Tests

• Modified CT
• CTA contrast
• Video Capsule of small intestine.

Malabsportion Tests

• Fat based tests, fecal fat test
• Not widely avaliable: hydrogeren breath test.

Large Intestine Diagonsics

• Disorders abscess/filstula, constipation and Diverticular disease. Inflammatory Bowel disease and obstruction along with polyps
• Toxic Megacolon
• Plain film, obstruction visualiation.

Tagged RBC Scan

• Colonoscopy and Sigmoidscope

Fecal Occult Blood Test

• Caused by Refluc esophagitis. Reflux Esophagitis or petic ulcer

Pathogen Testing

• Stool and parasites
• Microscopic test of ova in test

Diarrhea Types

• Enterhemorhagin (EHEC)
• Salmonella (never norma)
• Salmoneela enterica"Thyroid"
• Clostriodidies

Diagnostics Evaluation

• GDH Test antigen, Reflex testing and c Diff toxin Assay

Laboratories of Intestines

• antigen in tools
• Protozao of parasite of intestinal amobe

Small Bowel Test

• Nematodes roundworm, hookworm and pinworn,

Colon cancer test

• Stool test, colonoscope and sigmoniscope

Accessory Organ Functions

Gallbladder and pancreas is tested with nauesses, Vomit and Abdominal pain . Structural stones in this area. Tests: Ultrasound and cat scan will run blood and enzyme

Liver Diagnostics

• Structural problems (Masses for example) using Ultrasound
• CT and MRI Used to assesses level of fibroids and changes

Liver labs

• Albumin
• Transaminisess Transanimase: Enzyme that create insulin, the liver and kidney and muscle all help Albumin help control function

Billrubin tests

• Blood urine and Stool
• Urobilin
• Jaundice : BUILPUP of bilirubin in the blood
• Prehepatic Hepatocellalur and post herpatic

Alpha Fetoprotein

• Hepato cellular,

Hepatits Labs

Fecal Oral: A Vaccine vailable HbsG and Hcs AB. Viral hepatitis Labs of Acute. .

pancreatic cancer C19 and assesment response with treamtent