[01.32] Contrast Media in Radiology V2

Optical density

Contrast material creates a difference in this between anatomic structures, making details more visible

. Abdominal radiograph without contrast

In this type of imaging, the spine, pelvis, femoral heads, gas in stomach/bowels, and liver shadow can be noted

. Black

In a barium enema with air, this is how air appears

. Retrograde identification

In a barium enema with air, this process begins with the most distal and then the most proximal part

. Intravenous pyelography

This type of Kidney-Urinary Bladder (KUB) contrast radiography uses contrast to emphasize the vascular system from kidneys to ureters and bladder

. 1896

The year x-rays were discovered

. Air

The first recognized contrast agent

. Bismuth salts

Used in 1898 to image the gastrointestinal tract of a cat

. 1910

The year barium sulfate and bismuth solution were used with a fluoroscope

. Sodium iodide

Used in 1920 for imaging the urinary tract

. 1950

The decade modern ionic contrast agents were developed

. 1970s and 1980s

The decades non-ionic contrasts were developed

. Attenuation

The reduction of a beam’s intensity via scattering or absorption

. Positive Contrast Agent

This type of contrast material is radiopaque and will appear dense, white, or bright

. High atomic weights

Positive contrast agents owe their density or opacity to elements with this characteristic

. Iodine, bromine, barium

Examples of elements with high atomic weights used in positive contrast agents

. Negative Contrast Agent

This type of contrast material is radiolucent and will appear black or dark

. Cannot attenuate x-rays

A characteristic of negative contrast agents regarding x-ray beams

. Air, water

Examples of negative contrast agents

. Iodine-based contrast material

The most commonly used contrast material

. Barium sulfate

This contrast material is well-established for GI examinations and can be visualized through X-ray, CT, or fluoroscopy

. Rectally

To visualize the lower GI tract effectively, barium sulfate should ideally be administered this way

. Sterile saline (water)

This contrast material is visualized through ultrasound and is used for outlining body cavities, particularly useful with MRI

. Saline infusion sonohysterography

An example of imaging of the endometrium using water to check for lesions like polyps

. Paramagnetic substance

Gadolinium-based compounds are usually visualized through this imaging modality

. Enhance the magnetic properties of tissues

How paramagnetic substances improve contrast in MRI

. Blood vessels, tumors, and other structures

Paramagnetic substances are especially used for highlighting these in detail

. Iodinated benzene ring derivatives

Iodine-based contrast is composed of these

. Sodium and meglumine salts

Iodine-based contrast is formulated as these to adjust solubility, stability, and reduce viscosity

. Radiopaque (bright)

This is how iodine contrast medium appears

. Ionic high osmolar contrast media and Non-ionic low osmolar contrast media

Iodine-based contrast is prepared in terms of these osmolar contents

. Plain radiography and CT scans

Iodine-based contrast is used in these imaging modalities

. It is colorless

A key difference between contrast material and a dye, which shows color and may permanently discolor organs

. Higher concentration of dissolved particles in solution

A characteristic of higher osmolarity in ionic contrasts

. Dissociate into ions in the bloodstream

This characteristic of ionic contrast media can lead to increased risk of adverse reactions like pain and allergic response

. Increased image clarity

An advantage of ionic contrast media despite higher osmolarity

. Cheaper

A cost characteristic of ionic contrast media compared to non-ionic

. Diatrizoate sodium (Hypaque) and Iothalamate meglumine (Conray)

Examples of ionic monomer preparations

. Do not dissociate into ions in the bloodstream

This characteristic of non-ionic contrast media reduces the risk of adverse reactions

. Its safety profile and reduced side effects

Why non-ionic contrasts have largely replaced ionic contrasts

. Ionic dimers and non-ionic monomers

The two classifications of non-ionic contrasts

. Ioxaglate meglumine (Hexabrix)

An example of an ionic dimer

. Iopromide (Ultravist), Ioversol (Optiray), Iopamidol (Isovue)

Examples of non-ionic monomers

. Reduced tonicity (osmolality)

An advantage of non-ionic over ionic contrast media that leads to positive diuresis and rapid iodine clearance

. More expensive but safer

Cost and safety characteristics of non-ionic contrast

. Less risk for neurotoxicity

An advantage of non-ionic contrast, secondary to absence of carboxyl groups, increased OH groups, and balanced molecular distribution

. Does not cross the blood-brain barrier

A characteristic of non-ionic contrast that reduces neurotoxicity

. Intravenous

The most common route of contrast administration

. Humeral

This route of administration is a common site for intraosseous injection when IV access is not possible for critically ill patients

. Calyces

In intravenous pyelography, these cusp-like structures are visible five minutes after contrast administration

. Ureteropelvic Junction (UPJ), Iliac Vessel Crossover, Ureterovesical Junction (UVJ)

The three physiological constrictions of the ureter

. Urinary bladder

In intravenous pyelography, contrast reaches this structure more than 20 minutes after administration

. Hyperdense

In a Chest CT scan with contrast, the ascending and descending aorta appear this way

. Aortic dissection

An abnormal finding visible in a chest CT scan with contrast, appearing as a flap

. Coronary vessels

Contrast allows visualization of these in a magnified fluoroscopic image of the heart

. Circle of Willis

This vascular structure in the brain is clearly visualized with contrast after tissue removal in a reconstructed image

. Intraoperative cholangiogram

This procedure is done in the middle of surgery to rule out lesions in the biliary tract

. Cystic stump

Contrast is administered via this during an intraoperative cholangiogram

. D=duodenum, bif=bifurcation of the right and left hepatic ducts, CBD=common bile duct

The legend components for identifying structures in an intraoperative cholangiogram

. Fimbriae, Infundibulum, Ampulla, Isthmus, Intramural

The five fallopian tube segments from lateral to medial

. Hysterogram

This contrast imaging procedure of the female reproductive tract is used to rule out anomalies, inflammatory problems, or anatomical distortions

. Cervical canal

Contrast is administered via this for a hysterogram

. Hemangioma

The most common tumor of the liver, which can be diagnosed with contrast imaging, sparing the patient from biopsy

. Arterial phase, Venous portal phase, Delayed phase

The phases seen in an abdominal CT scan of the liver with contrast where a nodule appears, pools contrast, and then becomes isodense

. Glomerular filtration and tubular reabsorption

The two ways iodine-based contrast is excreted from the body

. Less soluble in water

A property of barium sulfate that makes it safer and less toxic

. Defecation

Barium sulfate is excreted via this process

. Oral (anterograde) or as an enema (retrograde through the rectum)

The two ways barium sulfate may be given

. Upper and Lower GI examinations, Abdominal CT scans

Indications for barium studies

. C6, T4, T10

The esophageal constrictions where barium contrast may not outline the lumen

. An irregularity in the contrast flow due to mass lesions along the wall

How cancer can be represented in a barium study of the esophagus

. Preliminary film

The initial film in a barium enema administration where only gas is seen within the intestinal tract without contrast

. "Full barium" phase

Another name for the initial phase of barium enema administration where contrast flow is seen real-time

. Abnormal dilation, abnormal constriction, anatomic distortions, outpouching

Pathologic abnormalities checked during the initial phase of a barium enema

. Re-introduction of air

The step in barium enema that makes it a double contrast evaluation

. Distensibility

Air is introduced in a retrograde manner in a barium enema to check this characteristic of the colon

. 6 cm

The maximum distention of the cecum in a barium study

. 3 cm

The maximum distention of the small bowel in a barium study

. Lateral decubitus position

The patient's position during an actual barium study

. Anechoic (black)

How water appears in ultrasound procedures

. It lets sound waves pass through and is not reflective

Why fluid appears black (anechoic) in ultrasound

. Endometrium

The black structure in the middle of the uterus in a sagittal view during saline infusion sonohysterography

. Submucosal fibroid or myoma

An example of a suspicious structure that can be appreciated with water contrast in saline infusion sonohysterography, otherwise blending with parenchyma

. Pneumoarthrogram

A study of joints using air

. Double-contrast arthrography

Pneumoarthrogram can be combined with water-soluble iodinated medium for this

. Microbubble contrast material

Air can be used as this type of contrast material to highlight vascular structures in ultrasound

. Crescent of air and density within joint, apparent space between humerus and glenoid fossa

Normal assessment findings in an x-ray of the shoulder after air injection (pneumoarthrogram)

. Gadopentetic acid

A paramagnetic contrast agent administered intravenously for MRI procedures

. Colorless

The preparation characteristic of gadopentetic acid

. Signal voids (black circles) on the common bile duct

How choledocholithiasis (stones) may appear in a paramagnetic contrast imaging of the hepatobiliary tract

. Unpredictable

A characteristic of idiosyncratic reactions to iodinated contrast media

. Allergic and anaphylactic reactions (hypersensitivity reactions)

Types of idiosyncratic reactions to iodinated contrast media

. Dose-related reactions and non-anaphylactic by nature

Characteristics of non-idiosyncratic reactions to iodinated contrast media

. Within 1 hour of injection

When idiosyncratic reactions to contrast media generally occur

. Urticaria (hives), pruritus (itching), rhinorrhea, nausea and vomiting, diaphoresis, dizziness

Examples of mild idiosyncratic reactions to iodinated contrast media

. Persistent vomiting, facial edema, laryngeal edema, dyspnea, bradycardia, tachycardia, sudden onset of abdominal cramps

Examples of moderate idiosyncratic reactions

. Life threatening arrhythmias, pulmonary edema, seizures, death

Examples of severe idiosyncratic reactions

. Heightened parasympathetic activity

Cardiovascular reactions to iodinated contrast media are induced by this

. Nephropathy

An adverse reaction to iodinated contrast media characterized by elevation of creatinine level of more than 0.5 mg, or >50% of baseline levels, 1-3 days after contrast examination

. Creatinine clearance

It is important to request this before a patient undergoes myelinated contrast to ensure kidney function is intact