Radiographic Procedures, Patient Preparation, and Contrast Media

Patient Communication and Preparation Protocols

• Communication modalities for patient preparation:

  • Verbal communication: Direct verbal dialogue explaining the procedural steps and clothing removal requirements to the patient.
  • Visual communication: Physical demonstrations performed by the radiographer (e.g., pointing to or touching one's own neck to indicate the removal of a necklace).
  • Tactile communication: Hands-on physical assistance provided to patients who experience limited mobility or difficulty reaching clasps behind their neck.
  • Property security and liability prevention: Removed personal items and jewelry must be placed directly into the patient's hands, accompanied by specific instructions on where to store them securely. This protocol eliminates accusations of property theft directed at clinical staff.
  • Artifact reduction and radiation safety: Radiographers and radiography students bear absolute responsibility for ensuring all extraneous items are removed prior to exposure. Eliminating external artifacts prevents unnecessary repeat exposures, thereby minimizing avoidable radiation doses to the patient.

• Internal preparation for gastrointestinal examinations:

  • Anatomical targets: Cleansing of the alimentary canal, specifically the stomach, small bowel, and large intestine (colon).
  • Upper GI series and small bowel follow-through preparation: Patients must remain NPO (nil per os / nothing by mouth) for $8\text{ hours}$ prior to the examination, or routinely NPO after midnight. This mandates zero food and zero water intake.
  • Clinical rationale for NPO status: Prevents residual food matter and fluid contents from obscuring the mucosal lining of the stomach, duodenum, and intestinal tract, ensuring clear visualization when introducing positive contrast agents.
  • Lower GI / Barium enema preparation: Involves the administration of pre-procedural cleansing enemas the evening before and/or the morning of the exam to evacuate all fecal matter and stool from the colon.
  • Scout imaging protocol: A preliminary radiograph obtained before introducing any contrast media.
  • Evaluation criteria on scout images: Radiographers examine the distribution of bowel gas and the presence of mottled, speckled black-and-gray densities within the colon indicative of retained fecal material. Patients displaying inadequate bowel evacuation cannot proceed with the contrast examination without corrective interventions, such as additional cleansing enemas.
  • Correlation with endoscopy: The preparatory protocols for barium enemas closely mirror the dietary restrictions and cleansing regimens utilized prior to colonoscopy procedures.

Contrast Media Classifications and Clinical Safety

• Positive contrast media:

  • Radiographic presentation: Radiopaque, appearing white on processed radiographs.
  • Primary types: Barium sulfate ($\text{BaSO}_4$), water-soluble iodinated contrast, and other iodine-based formulations.
  • Vascular contraindication: Barium sulfate must never be introduced into the vascular system (arteries or veins). Only water-soluble contrast media is permissible for intravascular injection.
  • GI perforation contraindication: In cases of known or suspected gastrointestinal perforation, barium sulfate is strictly contraindicated. Extravasation of barium through a perforation into the peritoneal cavity causes barium peritonitis, a condition where the contrast hardens like concrete within the abdominal cavity. Barium peritonitis carries high mortality rates and requires emergency surgical intervention. Water-soluble iodinated contrast media must be substituted whenever perforation is a clinical concern.

• Negative contrast media:

  • Radiographic presentation: Radiolucent, appearing black on processed radiographs.
  • Primary agents: Ambient room air, gases, and carbon dioxide ($\text{CO}_2$).
  • Vascular contraindication: Negative contrast agents must never be injected directly into veins or arteries.

• Double-contrast examinations:

  • Definition: Radiographic studies that simultaneously utilize both positive contrast (coating the mucosal walls in white) and negative contrast (distending the organ lumina in black).
  • Common application: Barium enema studies evaluating the mucosal architecture of the colon.

Radiographic Principles, Skeletal Anatomy, and Projections

• Orthogonal projection requirements:

  • Mandatory rule for extremities: Radiography of the upper extremities, lower extremities, and trauma examinations requires a minimum of two separate projections oriented precisely $90^\circ$ apart from one another.
  • Terminology: Projections taken $90^\circ$ apart are termed orthogonal views.
  • Standard orthogonal pairings: An anteroposterior (AP) or posteroanterior (PA) projection combined with a lateral projection (AP is most common for extremity imaging).
  • Diagnostic necessity: Single projections can fail completely to demonstrate bony fractures. A lateral view oriented $90^\circ$ to the initial view is critical for revealing hidden cortical disruptions and displacements.
  • Institutional trauma case study: During an attempt by a facility to secure Level II trauma center accreditation, a policy was instituted requiring radiographers to perform only a single radiographic view on trauma intake patients to maximize turnover speed. Staff objections were overruled. A patient presented with an obvious clinical ankle deformity; following protocol, only a single view was obtained, which failed to confirm the fracture. Upon radiologist review, an orthogonal lateral view was demanded, which immediately revealed the severe underlying fracture. This confirmed that two orthogonal projections remain non-negotiable.
  • Long bone imaging requirement: Radiographs of long bones must capture both adjacent joints: the proximal joint and the distal joint.

• Thoracic and sternal anatomy:

  • Anatomy visualized through rib structures: Evaluation of the sternum requires penetrating overlapping thoracic ribs and spine.
  • Sternal landmarks: The manubrium, sternal angle, sternal body (notable for its serrated, "sawtooth sharp" lateral margins), and xiphoid process at the inferior tip.
  • Related examinations: Routine chest radiography (PA and lateral), ribs, and sternoclavicular joints (articulation between the sternum and clavicle).

• Craniofacial radiography:

  • Structures: Cranial vault, facial bones, nasal bones, mandible, temporomandibular joints (TMJs—the articulation connecting the mandible to the temporal bone of the skull), and paranasal sinuses.
  • Clinical transition: Plain radiographic examinations of the skull and facial bones have largely been superseded by computed tomography (CT) imaging. Clinical exposures must be seized when encountered due to their relative rarity in current practice.

• Vertebral column divisions:

  • Extent: Spans from the base of the cranium to the coccyx, articulating laterally with the ilium of the pelvis.
  • Adult anatomical vertebral counts: Total sequence of $7-12-5-1-1$.
  • Cervical spine: $7$ vertebrae located in the neck.
  • Thoracic spine: $12$ vertebrae located in the upper back.
  • Lumbar spine: $5$ vertebrae located in the lower back.
  • Sacrum: $1$ fused bone in the adult.
  • Coccyx: $1$ fused bone in the adult.
  • Mealtime mnemonic for vertebral sequence: Breakfast at $7:00\text{ AM}$ ($7$ cervical), lunch at $12:00\text{ PM}$ ($12$ thoracic), and dinner at $5:00\text{ PM}$ ($5$ lumbar), progressing inferiorly down the gastrointestinal path.
  • Trauma imaging shifts: High-energy trauma such as falls and motor vehicle collisions are typically directed straight to CT scanners for rapid head and spine assessment rather than plain radiography.

• Abdominal plain film radiography:

  • Limitations: Standard abdominal radiographs (KUBs) offer limited soft tissue differentiation, primarily visualizing gross air-fluid levels, soft tissue masses, and occasionally radio-opaque renal calculi or gallstones.
  • Advanced assessment: CT imaging is favored for suspected acute appendicitis (inflammation of the appendix) and renal stones, while dynamic fluoroscopy is used for mucosal functional studies.

Gastrointestinal Fluoroscopic Procedures

• Fluoroscopic team dynamics and roles:

  • Equipment operation: The dynamic fluoroscopic tower is directly manipulated by the radiologist or radiologist assistant (RA).
  • Radiographer responsibilities: Room preparation, handing procedural supplies to the radiologist, maintaining patient modesty and positioning, providing physical assistance during patient rolling/turning, cleaning contaminated surfaces, and acquiring overhead post-fluoroscopy radiographs.

• Esophagography (Esophagram):

  • Anatomical system: Esophagus.
  • Contrast medium and administration: Orally administered positive contrast (barium sulfate suspension).
  • Clinical indication: Assessment of esophageal motility, luminal narrowing, strictures, and hiatal hernias.

• Upper Gastrointestinal (Upper GI / UGI):

  • Anatomical system: Stomach and duodenum.
  • Contrast medium and administration: Orally ingested barium sulfate.
  • Routine protocol combination: Often combined into an Upper GI with Esophagram. Dynamic fluoroscopy tracks the barium transit as it descends the esophagus, fills and coats the gastric rugae of the stomach, and transits through the C-loop of the duodenum.

• Small Bowel Follow-Through (SBFT / SMBFT):

  • Anatomical system: Small bowel (duodenum, jejunum, ileum).
  • Contrast medium and administration: Additional bottles of orally ingested barium sulfate.
  • Radiographic exposure interval timing: Serial KUB radiographs taken at strictly timed intervals.
  • Immediate radiograph taken upon completion of barium ingestion.
  • Radiograph taken at $30\text{ minutes}$.
  • Radiograph taken at $60\text{ minutes}$ (marking $30\text{ minutes}$ after the second exposure).
  • Subsequent overhead KUB exposures taken every hour ($2\text{ hours}$, $3\text{ hours}$, etc.) until anatomical completion.
  • Anatomical termination criteria: The examination is officially complete when the barium column crosses the ileocecal valve into the cecum or reaches the terminal ileum.
  • Transit considerations: Ambulatory outpatients who walk between timed exposures demonstrate significantly accelerated gastrointestinal motility. Bedridden inpatients require portable bedside radiography, which frequently slows transit times and may extend the examination across multiple hours or into the following day.

• Lower Gastrointestinal Series (Barium Enema / BE):

  • Anatomical system: Large intestine / colon.
  • Administration route: Rectal administration via an enema tip.
  • Flow dynamics: Retrograde administration (flowing backwards against normal peristalsis from the rectum into the rectosigmoid colon, descending colon, transverse colon, ascending colon, and cecum).

Genitourinary and Biliary Fluoroscopic Procedures

• Urinary system contrast requirements:

  • Mandatory agent: Exclusively water-soluble iodinated contrast media. Barium sulfate is absolutely contraindicated in the genitourinary tract.

• Intravenous Urography (IVU / IVP):

  • Historical terminology: Intravenous pyelography (IVP); modern designation: intravenous urography (IVU).
  • Anatomical system: Kidneys, ureters, and urinary bladder.
  • Administration route: Intravenous injection via peripheral venipuncture.
  • Physiology: Contrast enters the vascular bloodstream, is filtered across the glomeruli of the renal parenchyma, and is excreted down through the ureters into the bladder.

• Cystography (Cystogram):

  • Anatomical system: Urinary bladder ("cysto" refers to the bladder).
  • Administration route: Retrograde catheterization utilizing a urinary Foley catheter inserted via the external urethra directly into the bladder lumen.

• Voiding Cystourethrography (VCUG):

  • Definition of voiding: Active physiological micturition (urination).
  • Procedural methodology: A Foley catheter is introduced through the urethra to distend the urinary bladder with water-soluble iodinated contrast. The catheter is removed, and dynamic fluoroscopy captures active voiding directly on the examination table.
  • Diagnostic indications: Demonstrates functional urethral narrowing, strictures, anatomical blockages, and vesicoureteral reflux during active bladder contraction. If a patient is permitted to urinate off-table in a restroom, dynamic voiding anomalies are missed, though post-void images can document incomplete emptying or urinary retention.

• Endoscopic Retrograde Cholangiopancreatography (ERCP):

  • Acronym and definition: ERCP stands for Endoscopic Retrograde Cholangiopancreatography.
  • Anatomical system: Biliary system, encompassing the liver, gallbladder, pancreas, and the interconnecting bile ducts.
  • Anatomical visualization: The arborizing network of biliary channels is designated the "biliary tree".
  • Procedural technique: A specialized endoscope is advanced orally through the stomach into the descending duodenum to locate the ampulla of Vater. A cannula is advanced retrograde into the biliary ductal system, and water-soluble iodinated contrast is injected to assess strictures, calculi, or ductal pathology.

Vascular, Musculoskeletal, and Reproductive Radiography

• Vascular imaging (Angiography / Arteriography):

  • Morphological roots: "Art" refers to arteries; "angio" refers to blood vessels.
  • Anatomical target: Arterial and venous vasculature throughout the body.
  • Contrast requirements: Strictly water-soluble iodinated contrast media. Intravascular barium is lethal.

• Arthrography (Arthrogram):

  • Morphological root: "Arth" refers to joints (distinct from "art", vessel).
  • Target anatomy: Synovial joints, predominantly the shoulder, hip, and knee due to high rates of chronic biomechanical wear and tear.
  • Procedural steps: Under fluoroscopic guidance, a needle and catheter enter the intra-articular joint capsule to inject water-soluble iodinated contrast media, coating the joint cartilage and capsular boundaries.
  • Multimodality utilization: Plain fluoroscopic arthrography is routinely followed by cross-sectional imaging (CT or MRI) for high-resolution ligamentous and labral evaluation. Standalone arthrograms have largely transitioned to advanced cross-sectional imaging.

• Hysterosalpingography (HSG):

  • Target anatomy: Female reproductive tract, specifically the uterine cavity and fallopian (uterine) tubes.
  • Clinical indication: Infertility evaluations to determine structural patency ("patency" indicates unobstructed, open conduits).
  • Procedural pathway: A cannula or catheter is introduced through the vagina and transcervically into the uterus (strictly avoiding the urinary urethra). Water-soluble iodinated contrast (or occasionally specific oil-based contrast) is instilled.
  • Normal diagnostic appearance: The opacified uterine cavity assumes a triangular "Dorito shape". Normal bilateral patency is confirmed when contrast flows through two thin, tortuous fallopian tubes and spills freely into the peritoneal cavity. Absence of free peritoneal spillage indicates unilateral or bilateral tubal occlusion.

Specialized Imaging Modalities and Intrathecal Procedures

• Mammography:

  • Target tissue: Breast parenchymal tissue.
  • Indication: Screening and detection of breast carcinoma.
  • Demographics: Routinely performed on female patients, but also utilized clinically for male patients.
  • Contrast utilization: Typically performed without contrast media, though contrast-enhanced techniques exist.

• Myelography (Myelogram):

  • Anatomical target: The subarachnoid space surrounding the spinal cord and the intrathecal boundaries of the spinal canal.
  • Procedural technique: Under fluoroscopic localization, a spinal needle punctures the subarachnoid space (analogous to lumbar puncture or spinal anesthesia insertion). Non-ionic water-soluble contrast media is injected directly into the cerebrospinal fluid (CSF).
  • Route of administration: Intrathecal injection ("intrathecal" specifically designates injection into the spinal subarachnoid space).
  • Critical medication safety rule: Contrast media bottles explicitly labeled with warnings stating "NOT FOR INTRATHECAL USE" must never be introduced into the subarachnoid space, as non-approved formulations cause severe neurotoxicity and death.
  • Modern modality utilization: Largely replaced by non-invasive magnetic resonance imaging (MRI), though remaining clinically indicated for patients with MRI contraindications.

Questions & Discussion

• Academic resources and review guidance:

  • Lecture slides are archived on the Blackboard learning management system for student review.
  • Core assessment competencies for upcoming evaluations:
  • Procedural name of each diagnostic study.
  • Anatomical body system under investigation.
  • Category and specific chemical type of contrast media utilized.
  • Route and procedural method of contrast administration.

• Interactive session closure:

  • Question collection conducted via the digital chat console and live audio unmuting.
  • Session adjourned with instructions to reconvene at $12:00$.