1-INTRAVASCULAR CONTRAST MEDIA
Fundamental characteristics of contrast media are revised.
These recommendations are mainly based on the ESUR contrast media safety guideline v10 which is strongly encouraged to be used as a reference guide.
In case of doubt or need for more information consult the product's leaflet and international guides indexed in the references.
1A / IODINE COMPOUNDS
It is recommended to adjust the dose according to patient weight,
type of study,
required flow rate and contrast concentration.
DO NOT ADMINISTRATE
In patients with history of iodine contrast allergy or hyperthyroidism,
do not administrate.
RISK FACTORS FOR ACUTE POST-CONTRAST KIDNEY DAMAGE:
- Use of IV contrast or use of IA contrast with second-pass renal exposure if glomerular filtration rate (GFR) < 30 mL/min/1.73 m2.
- Use of IA contrast with first-pass renal exposure (ex: left heart,
thoracic or abdominal adrenal aorta or renal arteries) if GFR < 45 mL/min/1.73 m2 or in ICU patients.
- Known or suspected acute renal failure.
In ambulatory patients with risk of acute post-contrast renal damage:
- In our center,
patients' blood tests are reviewed prior to IV contrast administration to detect patients with renal failure
- It is advisable to obtain blood tests 7 days prior to administration and 48 hours after in patients at risk,
such as kidney disease,
recent intake of nephrotoxic drugs and heart disease.
METFORMIN AND IODINE CONTRAST MEDIA:
Remove metformin on the day of the test and 48 hours after iodine contrast administration,
measure the GFR and only reintroduce metformin if renal function has not deteriorated.
PREGNANCY AND BREASTFEEDING
It should not be used during pregnancy unless benefits outweigh the risk to both mother and baby.
In case of administration,
thyroid function of the baby at birth should be analyzed.
Breastfeeding can be continued normally without problem.
If the mother prefers not to continue breastfeeding for caution,
breastfeeding may be interrupted for 12 to 24 hours,
and never for a longer period.
All iodine contrast media can be cleared by hemodialysis or peritoneal dialysis.
there is no evidence that dialysis protects patients with impaired renal function from contrast-induced nephropathy.
In hemodialysis patients,
it is not necessary to schedule the session according to the time of contrast administration nor is an extra session required to clarify the contrast.
In patients on continuous ambulatory peritoneal dialysis,
no hemodialysis is required to clarify the contrast.
OTHER INTERACTIONS AND PRECAUTIONS
Thyroid function tests or radioactive iodine treatment must be scheduled in the next two months after IV administration.
1B / COMPOUNDS BASED ON GADOLINIUM (TRADED IN SPAIN)
The European Medicines Agency (EMA) and the Spanish Agency for Medicines and Health Products (AEMPS) have reported that small amounts of gadolinium may be retained in the patient's brain tissue,
this retention is greater with linear agents than with macrocyclic ones,
and the long-term effects of this deposit are unknown.
They therefore recommend:
It is recommended that dose is adjusted according to patient's weight,
type of study and type of contrast and reflected in the report.
DO NOT ADMINISTER
Patient presents history of allergy to gadolinium-based contrasts.
The risk of acute reaction to a gadolinium-based contrast agent is lower than for an iodine-based contrast agent.
severe reactions to gadolinium-based contrast media may occur.
The risk of nephrotoxicity is low when used at approved doses.
Gadolinium-based contrasts should not be used as an alternative to iodine-based contrasts as they are more nephrotoxic at equivalent X-ray attenuation doses.
RENAL INSUFFICIENCY AND NEPHROGENIC SYSTEMIC FIBROSIS (NSF):
The patients at risk for NSF are:
- Patients with chronic renal failure (CRF) in stages 4 and 5 (GFR < 30 ml/min/1.73m2).
- Dialysis patients.
- Patients with acute renal failure.
Gadolinium-based contrasts are not recommended for patients with GFR < 30 ml/min/1.73m2.
The macrocyclic gadolinium-based contrasts currently approved by EMA are those with the lowest risk of FSN.
The linear contrasts that can be used to study liver lesions show an intermediate risk of NSF.
In patients already affected by NSF,
they should only be used if the indication for the scan is vital,
and in that case,
only intermediate or low-risk contrasts should be used.
METFORMIN AND GADOLINIUM-BASED CONTRAST MEDIA:
No special precautions are necessary for diabetic patients on Metformin treatment who are to be given a gadolinium-based contrast medium.
PREGNANCY AND LACTATION
In pregnancy only administer when there is a clear indication of contrast MR.
the lowest possible dose of the most stable gadolinium-based contrasts should be administered (intermediate and low NSF risk).
No neonatal tests are required after administering a gadolinium-based contrast medium to the pregnant mother.
It is not considered necessary to discard the milk within 24 hours after administration of the contrast (because high-risk ones are no longer used),
but the patient can discuss this with her doctor if she wishes to do so.
Never administer if pregnant or breastfeeding woman has impaired kidney function.
Regardless of whether the patient is on dialysis,
always perform prior assessment of renal function before administering contrast.
All gadolinium-based contrast media can be cleared by hemodialysis or peritoneal dialysis.
there is no evidence that dialysis protects patients from NSF.
For hemodialysis patients,
it is recommended to schedule the session according to the time of contrast administration or to perform an extra hemodialysis session as soon as possible after administration.
For patients on continuous ambulatory peritoneal dialysis,
the need for hemodialysis will be assessed in conjunction with the prescribing physician.
DISODIUM GADOXETATE (Primovist ®) SPECIAL CONSIDERATIONS
- Linear liver-specific contrast
- Dosage: 0.1ml/kg weight
- Renal and hepatic excretion at 50% and 10% binding to plasma proteins.
- Hepatobiliary phase between 20-120 minutes after administration.
Fig. 2 This time window decreases to 60 minutes in patients with kidney failure or elevated bilirubin values (> 3mg / dl)
- Avoid especially in the perioperative period of liver transplantation.
- Other precautions and contraindications similar to other gadolinium-based contrasts.
1C/ PROPHYLACTIC TREATMENT OF ALLERGIC REACTIONS
Patients with a history of allergy to contrast and previous study by the Allergology service can perform a prophylactic premedication for allergic reactions.
These patients should remain in the center for 30-60 minutes after contrast administration in case of a late allergic reaction was presented.
1D/ ADMINISTRATION OF IODINE AND GADOLINIUM ON THE SAME DAY
2-ORAL CONTRAST MEDIA
3-ULTRASOUND CONTRAST MEDIA
Composed of inert gas microbubbles,
stabilized with different substances,
sugars or surfactants (SonoVue®).
- Dosage: 2.4 ml IV bolus followed by 10 ml bolus of physiological saline solution.
a second dose may be administered.
- Contraindications: Acute myocardial infarct,
congestive heart failure III / IV,
severe pulmonary hypertension,
Avoid the use of contrast media the 24 hours prior to treatment with extracorporeal shock waves.
- It is excreted exhaled through the lungs,
not through the kidneys.
Check the leaflet for each drug for more information.
The preparations are referenced on the back of the request flyer.
5A / ULTRASONOGRAPHY Fig. 4
CYSTOGRAMS AND URINARY CATHETER STUDIES Fig. 5
High osmolarity iodine contrast (Plenigraf® iodine concentration of 165mg/ml) can be used.
Dosage: 3-4 ml/kg of weight.
Average total adult dose of 250 ml.
Contrast is introduced depending on patients tolerance.
Maximum total dosage of 400 ml.
How it´s done:
Prophylactic treatment with Levofloxacin as seen previously on Table 7.
5C / INTRAVENOUS UROGRAPHY Fig. 6
Use of low osmolarity contrast agents (drag less water and condition higher tubular concentration),
non-ionic monomers (safer due to lower protein binding index).
5D / GASTROINTESTINAL TRACT CONVENTIONAL STUDIES
- Barium and Gastrografin® described in Table 6.
- Non-ionic low osmolarity iodine monomers and dimers: Fig. 7
- It is the safest contrast but the one that provides the worst image quality.
- Indicated whenever there is a suspicion of fistula or leakage at the thoracic level.
At abdominal level,
it can be used as an alternative to Barium.
- Omnipaque® and Visipaque® are the only ones accepted in the leaflets for gastrointestinal studies with a maximum dose of 100 mL for the esophagus and 200 mL for the stomach and small intestine.
most guidelines do not set a specific dose limit and it does not appear to exist any relevant side effects.
- Use undiluted.
- Upper GI tract studies:
- Barium enema:
- Cholangiography and cholecystography by Kher tube or cholecystostomy: Fig. 8
No intravenous contrast administered: No preparation required.
Intravenous contrast: 6 hour fasting.
Negative oral contrast: administer 3-4 glasses of water to replenish the intestinal loops.
Positive oral contrast: Oral Gastrografin® is administered.
It is used mainly for: peritoneal carcinomatosis,
leakage or anastomosis dehiscence,
and abdominal collections. 0.5-1.5L of water is administered with Gastrografin® in a concentration of 3%: 30 ml of Gastrografin® in 1 L of water or a plug of Gastrografin® for every 200 ml of water (similar to a glass).
CT enterography: Fig. 10
- 6 hour fasting.
- Oral neutral contrast similar to that used for MR.
- Optional administration of antiperistaltic medication (N-Butyl-scopolamine or Glucagon IV).
In diabetic patients use N-Butyl-scopolamine.
Do not use N-Butyl-scopolamine in patients with prostatic hypertrophy or urine retention.
- Acquisition with IV contrast in order to assess wall enhancement and possible lesions with different phases depending on clinical suspicion.
- 6 hour fasting.
- Previous preparation of the colon:
- Distension of the colon with rectal probe insufflation with ambient air or with CO2.
Ambient air is less expensive and is administered manually until the patient reports a feeling of discomfort.
CO2 requires continuous insufflation by means of automatic equipment since its absorption by the mucous membrane is very fast,
but it entails less residual discomfort.
There is a tendency to prefer CO2.
Ambient air is used in our centre.
CT enema: Fig. 11
- Preliminary preparation not necessary
- A can of barium is emptied of its contents,
filled with warm water and Gastrografin® or non-ionic low osmolarity iodine contrast is added (200 mL in 600 mL of water or 50 mL in 750 mL of water respectively).
- A normal rectal cannula is used.
The use of the balloon depends on the clinical indication,
location (do not mask low anorectal pathology) and the retention capacity of the patient.
- It is generally well tolerated (< 3% interruptions of the test for pain) although contrast leakage may occur due to incontinence.
CT urography: Fig. 12
- 6 hour fasting.
- Abundant hydration (1 - 1.5 L of water) to promote diuresis.
- Optionally Furosemide can be administered to force diuresis (0.1 mg/kg up to a maximum dose of 10 mg).
CT cystography: Fig. 13
- For evaluation of bladder lesions,
especially traumatic or iatrogenic lesions.
- It is important to carry out a basal phase first.
- Administer 350-400 ml of diluted iodine contrast through the bladder catheter up to patient tolerance:
- Plenigraf® (100ml) diluted in sterile water (400 ml) can be used.
- Non-ionic low osmolarity iodine contrast can be diluted to 10%.
A simple way is to empty 50 ml of a 500 ml bottle of physiological saline and fill with 50 ml of non-ionic low osmolarity iodine contrast.
5F/ MAGNETIC RESONANCE
Magnetic Resonance without contrast: no preparation required.
Magnetic Resonance with contrast: 6 hour fasting.
MR enterography: Fig. 14
- Oral contrast used: Two-phase contrast (high signal intensity in T2 sequences and low in T1 sequences): dilute one bottle of Mannitol (250 ml at 10%) in 750 ml of water.
The patient should drink it during the hour prior to the test.
- Spasmolytics: In diabetic patients,
glucagon is contraindicated and N-Butyl-scopolamine is recommended.
In patients with prostatic hypertrophy or urine retention,
N-Butyl-scopolamine is contraindicated and Glucagon is recommended.
- In prone position to reduce respiratory and peristalsis artifacts.
- Cleaning of the colon as usual,
as for enema.
- Administer between 1 and 1.5 L of tempered serum rectally,
according to tolerance.
Evaluate progressive filling of the colon using MR fluoroscopy technique.
Anterior filling of the colon is also possible and well tolerated,
although optimal distension of the colon is not achieved.
- It can be associated with oral contrast used for MR enterography.
- If a biopsy has been previously performed and the study is for the detection of carcinoma,
it is essential to delay the exploration by 6 or more weeks in order to avoid glandular hemorrhagic changes or periglandular fibrotic changes that may interfere with the interpretation of the study.
- If the study is for staging of a known prostate carcinoma it is not necessary to wait this period of time to perform the scan.
Cholangiopancreatography with Secretin: Fig. 15
- 4-hour fasting.
- Negative oral contrast is administered about 5 minutes before the study to decrease the signal of the remaining fluids of the digestive tract (200 ml of water with 3 ml of gadolinium or with Gastrografin®).
- General morphological sequences of the hepatobiliopancreatic tree are performed,
followed by cholangiopancreatographic sequences covering all pancreatic segments.
- The best sequence is chosen to assess the main pancreatic duct and its outlet into the papilla.
Then secretin is administered via IV at a dose of 1 U/kg,
performing sequences every minute for 10 min (total exploration time 30-35 min).
- General recommendations:
- It is recommended to administer spasmolytic before the test (Glucagon 1 mg SC or N-Butyl-scopolamine IV).
- In order to improve the evaluation of anatomical structures,
rectal and/or vaginal gel is introduced depending on the clinical indication.
Intermittent probe without balloon (14F,
16F) and wide cone syringe are used.
- Rectal gel: 150 cc diluted with 50% sterile water
- Vaginal gel: 25-50 cc undiluted
- Bladder to medium repletion.
- Endometriosis: Fig. 16
- Pelvic floor: