Contrast media in radiology - PowerPoint Presentation

Slide1

Contrast media in radiology

Suppat

ittimakin

, MD.

Slide2

Contrast media

Substance used to enhance the contrast of the structures or fluid within the body in medical imaging

Types of contrast agent

- Iodinated contrast agent

- MR contrast agent: Gadolinium-based contrast agent

- Negative contrast agent

 air

Slide3

Iodinated Contrast media

Radiopaque contrast agents are often used in radiography and fluoroscopy to help delineate borders between tissues with similar

radiodensity

Types of iodinated contrast media

- Ionic

- Non-ionic

Slide4

Effect

of intravenous contrast injection

Slide5

Contrast media

Ionic contrast

agents:

Hyperosmolarity

to

blood

Should not

be used for

myelography

or in injections that may enter the spinal canal (because neurotoxicity is a risk) or the bronchial tree (because pulmonary edema is a

risk)

Incidence of irreversible renal failure in some medical condition such as

paraproteinemia

in multiple myeloma

Slide6

Contrast media

Nonionic contrast agents:

Low-

osmolar

(but still hyperosmolar relative to

blood ; 300 mg I/ml)

or

iso-osmolar

(with the same

osmolarity

as blood)

Now routinely used

 F

ewer adverse effects

Slide7

Slide8

Slide9

MR contrast agent

Extracellular contrast agent

Organ specific agent

Blood pool agent

Slide10

Gadolinum-based

mr

contrast

Improve

visilbility

of the internal body structures in MRI

Shortening of the T1 relaxing time of the atom

Do not pass blood brain barrier

Slide11

Slide12

Negative contrast media

Air: Use in double-contrast fluoroscopy

Slide13

Contrast reaction

Slide14

Goal of contrast usage

1

) to assure that the administration of contrast is appropriate for the patient and the

indication

2

) to minimize the likelihood of a contrast

reaction

3

) to be fully prepared to treat a reaction should one occur

Slide15

Adverse effect of intravenous contrast media

Allergy

Contrast-induced nephropathy

Nephrogenic systemic fibrosis

Contrast extravasation

Slide16

Allergy

Slide17

Risk factor for intravenous contrast reaction

Allergy

Asthma

Renal insufficiency

Cardiac status

Miscellaneous factors: Age, underlying disease such as hyperthyroidism,

paraproteinemia

in multiple myeloma, sickle cell anemia, etc.

Slide18

Allergy

Allergic of prior contrast usage

 increased 5 fold likelihood ratio

Allergic rhinitis ??

Seafood allergy ??

History of anaphylaxis

Slide19

Asthma

A history of asthma may indicate an increased likelihood of a contrast reaction

Especially active

hyperresponsive

airway disease

Slide20

Renal insufficiency

Can causes contrast-induced nephropathy (CIN), nephrogenic systemic fibrosis (NSF)

Metformin usage

Slide21

Cardiac disease

Congestive heart disease, severe aortic stenosis, pulmonary hypertension, severe cardiomyopathy

May increased risk of

contrast reaction

Attention

should be paid to limiting the volume and osmolality of the contrast media.

Slide22

Premedication

Approximately

90% of such adverse reactions are associated with direct release of histamine and other mediators from circulating basophils and eosinophils

Pathophysiologic explanations include activation of

mast cells and basophils

releasing histamine, activation of the contact and complement systems, conversion of L-arginine into nitric oxide, activation of the XII clotting system leading to production of

bradykinin,

and development of

“

pseudoantigens

”

Slide23

Premedication

Dose response studies in humans of the suppression of whole blood histamine and basophil counts by IV

methylprednisone

show a reduction in circulating basophils and eosinophils by the end of the

first

postinjection

hour

However, reaching

statistical

significance

compared with controls by the end of the second hour, and maximal statistical

significance at

the end of 4 hours

Slide24

Recommended premedication regimens

Elective Premedication

Two

frequently used regimens are:

First regimen:

Prednisone – 50 mg by mouth at 13 hours, 7 hours, and 1 hour before contrast media injection, plus

Diphenhydramine (Benadryl®) – 50 mg intravenously, intramuscularly, or by mouth 1 hour before contrast

medium

Slide25

Recommended premedication

regimens

Second regimen:

Methylprednisolone

(Medrol®) – 32 mg by mouth 12 hours and 2 hours before contrast media

injection

An

anti-histamine (as in option 1) can also be added to this regimen

injection

If the patient is unable to take oral medication, 200 mg of hydrocortisone intravenously may be substituted for oral prednisone

Slide26

Recommended premedication

regimens

Emergency Premedication

(In Decreasing Order of Desirability)

Methylprednisolone sodium succinate (

Solu

-Medrol®) 40 mg or hydrocortisone sodium succinate (

Solu-Cortef

®) 200 mg intravenously every 4 hours (q4h) until contrast study required plus diphenhydramine 50 mg IV 1 hour prior to contrast

injection

Slide27

Recommended premedication

regimens

Dexamethasone sodium sulfate (

Decadron

®) 7.5 mg or betamethasone 6.0 mg intravenously q4h until contrast study must be done in patent with known allergy to

methylpred-nisolone

, aspirin, or non-steroidal anti-inflammatory drugs, especially if asthmatic. Also diphenhydramine 50 mg IV 1 hour prior to contrast injection.

Note

:

IV steroids have not been shown to be effective when administered less than 4 to 6 hours prior to contrast injection.

Slide28

premedication

Type of contrast agent

Osmolarity

:

Hyperosmolality

is associated with the stimulation of release of histamine from basophils and mast cells

Complexity and molecular size: Increase

in the size and complexity of the contrast molecule may potentiate the release of histamine

Nonionic monomers also produce lower levels of histamine release from basophils compared with high-osmolality ionic monomers, low-osmolality ionic dimers and

iso

-osmolality nonionic dimers

Slide29

ACUTE CONTRAST REACTION

Allergic-liked reaction : from histamine which is released by mast cell and basophil

Physiologic reaction :

direct

chemotoxicity

,

osmotoxicity

(adverse effects due to

hyperosmolality

) or

molecular binding to certain activators

F

requently

dose and concentration dependent

Frequent reaction:

vagovagal

reaction,

feeling of apprehension and accompanying diaphoresis

Rare reaction:

Cardiac arrhythmias, depressed myocardial contractility, cardiogenic pulmonary edema, and seizures

Slide30

Delayed contrast reaction

M

ost

commonly cutaneous and may develop from 30 to 60 minutes to up to one week following contrast material

exposure

Can occurring

between three hours and two days

Symptoms; allergic-liked cutaneous reaction (most common), nausea/

vomitting

, fever, headache, iodine-related

sialoadenopathy

,

polyarthroplasty

Slide31

Evaluation of the contrast reaction

Mild

reaction

Signs and symptoms are self-limited without evidence of progression. Mild reactions include:

Allergic-like

: Limited

urticaria

/

pruritis

Limited cutaneous edema Limited “itchy” / “scratchy” throat Nasal

congestion/ Sneezing

/ conjunctivitis / rhinorrhea

Physiologic

: Limited

nausea /

vomiting/ Transient

ushing

/ warmth / chills Headache / dizziness / anxiety / altered taste Mild

hypertension/ Vasovagal

reaction that resolves spontaneously

Slide32

Evaluation of the contrast reaction

Moderate

Signs

and symptoms are more pronounced and commonly require medical management. Some of these reactions have the potential to become severe if not treated. Moderate reactions include:

Allergic-like

Diffuse

use

urticaria

/

pruritis

, Diffuse

erythema, stable vital

signs, Facial

edema without

dyspnea, Throat

tightness or hoarseness without dyspnea

Wheezing / bronchospasm, mild or no hypoxia

Slide33

Evaluation of the contrast reaction

Moderate

Physiologic

Protracted nausea / vomiting Hypertensive urgency Isolated chest pain

Vasovagal reaction that requires and is responsive to treatment

Slide34

Evaluation of the contrast reaction

Severe

Allergic-like

Diffuse

edema, or facial edema with dyspnea

Diffuse

erythema with hypotension Laryngeal edema with stridor and/or

hypoxia,

Wheezing / bronchospasm, S

ignificant hypoxia,

Anaphylactic shock (hypotension + tachycardia)

Physiologic

Vasovagal reaction resistant to treatment Arrhythmia

Convulsions, seizures Hypertensive emergency

Slide35

Treatment of Mild reaction

T

ypically

do not require medical

treatment

Vital signs should be obtained to detect hypotension that may be clinically silent while the patient is supine

O

bserved

for 20 to 30 minutes, or as long as

necessary

Antihistamine IV

Slide36

Treatment of Moderate to severe reaction

IV fluid

Antihistamine : Benadryl 1 mg/kg IV for moderate

urticaria

Epinephrine 0.1 mg/kg IV or 0.3 mg IM for profound hypotension, anaphylaxis, bronchospasm

Betaagonist

inhalator for mild and moderate bronchospasm

Slide37

Contrast-induced nephropathy (

cin

)

Slide38

Contrast-induced nephropathy

A

sudden deterioration in renal function that is caused by the intravascular administration of iodinated contrast medium

Diagnosis by use percent

change in the baseline serum creatinine

and

absolute elevation from baseline serum

creatinine (absolute

increase of 0.5 mg/

dL

over a

baseline)

Slide39

Definition of acute renal injury

The

diagnosis of AKI is made according to the AKIN criteria if one of the following occurs within 48 hours after a nephrotoxic event (e.g., intravascular iodinated contrast medium exposure

):

Absolute

serum creatinine increase ≥0.3 mg/

dL

(>26.4

μmol

/L

)

A

percentage increase in serum creatinine ≥50% (≥1.5-fold above baseline

)

Urine output reduced to ≤0.5 mL/kg/hour for at least 6 hours

.

Slide40

Renal function

Serum creatinine concentration is the most commonly used measure of renal

function

BUT!!! Serum creatinine has limited accuracy for evaluate GFR

Calculated estimated glomerular

filtration

rate (

eGFR

) is more accurate than is serum creatinine at predicting true GFR

eGFR

is gaining attention as a potentially better marker of CIN

risk

Slide41

Risk factors

P

re-existing

severe renal

insufficiency

 Most important risk factor

-

eGFR

< 30 ml/min/1.73 m

2

 significant risk

Underlying disease: DM, Cardiovascular disease, Multiple myeloma, Hypertension

Dehydration

D

iuretic use

A

dvanced age

M

ultiple

iodinated contrast medium doses in a short time interval (<24 hours)

Slide42

Prevention

Avoid usage of the iodinated-contrast agent

Select type of contrast agent :

LOCM are less nephrotoxic than HOCM in patients with underlying renal

insufficiency

.

Volume expansion : Major effective action

- 0.9

% saline at 100 mL/

hr

, beginning 6 to 12 hours before and continuing 4 to 12 hours

after intravenous iodinated contrast administration

N-acetylcysteine : unknown

mechanism

Slide43

Renal insufficiency

Most low-osmolality iodinated contrast media are not protein-bound, have relatively low molecular

weights

, and are readily cleared by

dialysis

Unless an unusually large volume of contrast medium is administered, or there is substantial underlying cardiac dysfunction, there is

no need

for urgent dialysis after intravascular iodinated contrast medium administration

Slide44

Nephrogenic systemic fibrosis (NSF)

Slide45

Nephrogenic systemic fibrosis

Fibrosing

disease, primarily involving the skin and subcutaneous tissues

but

also

involve

other organs, such as the lungs, esophagus, heart, and skeletal

muscles

Initial

symptoms typically include skin thickening and/or

pruritis

M

ay

develop and progress rapidly, with some affected patients developing contractures and joint

immobility

In

some patients, the disease may be

fatal

Slide46

Association

Gadolinium-based MR contrast

Acute kidney injury (AKI)

Chronic renal disease

Patients

with end-stage CKD (CKD5,

eGFR

< 15 mL / min/1.73 m2) and severe CKD (CKD4,

eGFR

15 to 29 mL / min/1.73 m2) have a 1% to 7% chance of developing NSF after one or more exposures to at least some GBCAs

Slide47

Recommendation

ACR Committee on Drugs and Contrast Media believes that patients receiving any GBCA should be considered at risk of developing NSF if any of the following conditions applies:

on dialysis (of any form)

severe or end-stage CKD (CKD 4 or 5,

eGFR

< 30 mL / min/1.73 m2) without dialysis

eGFR

30 to 40 mL / min/1.73 m2 without dialysis*

AKI

Slide48

NSF with hemodialysis

Hemodialysis ???

M

ost

patients who developed NSF had end-stage kidney disease and were on dialysis at the time of

exposure

So, hemodialysis cannot prevent NSF !!!

Slide49

Contrast extravasation

Slide50

Contrast extravasation

Leakage of the contrast agent from systemic circulation

Incidence 0.1% - 0.9%

Sign and symptom:

Complain

of initial swelling or tightness, and/or stinging or burning pain at the site of

extravasation

E

dematous

, erythematous, and

tender nearby the injected site

Slide51

Slide52

Slide53

risk of contrast extravasation

Patients

who cannot communicate adequately

S

everely

ill or debilitated

patients

P

atients

with abnormal circulation in the limb to be injected

:

- Atherosclerotic

peripheral vascular

disease

- Diabetic

vascular disease, Raynaud’s disease, venous thrombosis or

insuffciency

- Prior

radiation therapy or extensive

surgery

Slide54

risk of contrast extravasation (cont.)

>24 hour of injected site

Multiple venous

punture

High injected flow rate ???

Amount of injected contrast agent ???

Slide55

Sequelae of contrast extravasation

Acute local inflammatory response (24-48

hr

)

 due to

hyperosmolarity

of the contrast media

Hyperosmolar contrast agent can cause more severe reaction than low-

osmolar

contrast agent

Most extravasations are limited to the immediately adjacent soft tissues (typically the skin and subcutaneous

tissues), and usually

there is no permanent

injury

Slide56

Complication of the contrast extravastion

Compartment syndrome

 occur after large amount of contrast leakage

S

kin ulceration

Soft tissue

necrosis

Slide57

Slide58

Treatment of contrast extravasation

Elevation of the affected extremity above the level of the heart



decrease capillary hydrostatic pressure and

promote

resorption of

extravasated

fluid

W

arm

or cold compresses

???

A

spirate

the

extravasated

contrast medium through an inserted needle or

angiocatheter

???

Local injection

of other agents such as corticosteroids or hyaluronidase

???

Surgical consult :

progressive swelling or pain, altered tissue

perfusion,

change in sensation in the affected limb, and skin ulceration or blistering

Slide59

References

Introduction ACR Manual on Contrast Media – Version 10.1, 2015

Slide60

Thank you for your ATTENTION