MRI Safety and Patient Preparation Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which action is essential for patient cooperation during an examination?

Using restraints if necessary

Providing sedatives before the procedure

Allowing the patient to wear makeup

Informing the patient about the procedure (correct)

Why should patients avoid wearing makeup during an MRI examination?

It might cause allergic reactions

Makeup may impair imaging quality

Makeup can block RF signals

Some makeup products may contain metallic particles (correct)

What is one of the first precautions to take before an MRI scan?

Ensure the patient is wearing loose clothing

Check for any patient history of allergies

Screen the patient and accompanying person for metallic objects (correct)

Prepare sedatives for patient control

What could happen if wires and coils touch the patient’s body during an MRI?

Potential burns due to insulation failure Signup and view all the answers

What should be avoided to prevent loop formation during an MRI scan?

Allowing the patient to cross their legs or arms Signup and view all the answers

In an emergency situation, what is the first priority?

To remove the patient from the scanner room Signup and view all the answers

How does the computer ensure patient safety concerning tissue heating during an MRI?

By estimating heating levels before scanning Signup and view all the answers

What is a known consequence of RF pulses in MRI scans?

Causing tissue heating under specific conditions Signup and view all the answers

Why is it important to enter the patient’s weight correctly in an MRI estimate?

To prevent excessive RF exposure. Signup and view all the answers

Which of the following factors can affect a patient's completion of an MRI scan?

The type of scan used and method of entry. Signup and view all the answers

What is the recommended precaution for patients during an MRI scan due to acoustic noise?

Offering ear protection to all patients. Signup and view all the answers

What should a patient do if they are pregnant and scheduled for an MRI scan?

Inform their healthcare provider and MRI technologist. Signup and view all the answers

What are some methods to improve patient comfort during an MRI scan?

Using bore lighting and ventilation. Signup and view all the answers

What action should be taken in case of a patient needing medical attention during an MRI scan?

Press the emergency stop button on the console or magnet. Signup and view all the answers

What is the potential consequence of a magnet quench in an MRI facility?

Several days of downtime for the magnet. Signup and view all the answers

What can vary widely in terms of patient anxiety triggering aborted MRI scans?

The percentage of aborted scans reported. Signup and view all the answers

What should a patient remove before entering the MRI equipment room?

Personal possessions such as jewelry Signup and view all the answers

Why is it important to check the patient's identity before any MRI examination?

To avoid performing the scan on the wrong patient Signup and view all the answers

What type of attitude might patients exhibit due to anxiety before an MRI scan?

Aggressive or apprehensive Signup and view all the answers

What is the role of the technologist in easing a patient's anxiety?

Convincing them with a soft tone and providing comfort Signup and view all the answers

What should be done with wheelchairs and trolleys before the scan?

They must be kept outside the magnet room Signup and view all the answers

During the MRI scan, how long does the procedure typically take?

30 to 40 minutes Signup and view all the answers

What should patients do during the MRI scan to ensure quality images?

Stay completely still and relaxed Signup and view all the answers

What is the primary concern regarding personal items like credit cards in the MRI room?

The scanner may erase their information Signup and view all the answers

What is the primary safety precaution regarding laser alignment lights during MRI procedures?

Patients should close their eyes during landmarking. Signup and view all the answers

What type of contrast agent is Gadolinium classified as?

Positive relaxation agent. Signup and view all the answers

Which of the following conditions is a contraindication for the use of Gadolinium?

Hematological disorders. Signup and view all the answers

What is the effective dosage of Gadolinium recommended per kilogram of body weight?

0.1 mmol/kg. Signup and view all the answers

What is the primary mechanism by which iron oxide affects nearby hydrogen atoms?

It shortens relaxation times of nearby hydrogen atoms. Signup and view all the answers

Which imaging technique benefits significantly from the use of Gadolinium due to its ability to cross the blood-brain barrier?

MRI of the CNS. Signup and view all the answers

Which side effect is NOT associated with the use of iron oxide?

Increased appetite Signup and view all the answers

What is a potential side effect of Gadolinium administration?

Mild transitory headaches. Signup and view all the answers

Why is iron oxide contraindicated in certain patients?

It can cause discoloration around the infusion site. Signup and view all the answers

How does Gadolinium function as a contrast agent in MRI imaging?

It reduces T1 relaxation times of nearby water protons. Signup and view all the answers

What is the recommended dosage of iron oxide based on body weight?

0.56 mg of iron per kg of body weight Signup and view all the answers

Which of the following is not a side effect associated with Gadolinium use?

Insomnia. Signup and view all the answers

In which clinical application is iron oxide primarily used?

Liver imaging Signup and view all the answers

Study Notes

MRI Safety, Preparation, and Contrast Agents

MRI Safety:
- Patient identity is checked before scans
- Patients may be anxious; technicians should use a calm manner
- Children and uncooperative patients may need sedation
- Patients must remove all metal objects (jewelry, watches, keys, etc.)
- Wheelchairs/trolleys must remain outside the MRI room
- Patients lie down on a table that moves through the scanner tunnel
- The region of interest is positioned in the center of the magnet
- Patients can hear radiologist/technologist instructions and respond
- The entire process takes 30-40 minutes
- Patients are expected to remain relaxed and still
- Patients can resume normal activities after the scan
Patient preparation and Safety:
- Patients should be informed about the process.
- Avoid makeup containing metallic particles
- Ensure patient comfort to ensure stillness
- Guide patients on breathing and swallowing
- Patients with certain implants and conditions might be unsuitable for MRI
  - Aneurysm clips
  - Cardiac pacemakers
  - Otologic/ocular implants
  - Cochlear implants
  - Metallic foreign bodies (especially in the eye)

Precautions

Metallic Objects:
- Screen patients and their accompanying persons for metal objects.
- Strong magnetic attraction poses severe risks
Electrical Wires:
- Wires/coils must be well-insulated to prevent burns
- Body parts should not touch the magnet bore
- Avoid forming wire loops
- Avoid body part loop formations (e.g., crossed arms/legs)
Emergency Preparedness:
- MR facilities have procedures for accidents and emergencies
- Scan room doors should have stickers/labels of prohibited items
Radiofrequency (RF) Power Effects:
- The RF pulses used in MRI can cause tissues to absorb RF power and potentially heat them.
- Heating is based on patient size, pulse timing etc.
- Computer estimates heating levels vs preset limits
- System adjusts parameters if necessary
- Accurate patient weight is crucial
Claustrophobia and Sedation:
- Patient anxiety and claustrophobia can hinder MRI completion
- Scan abort rates in these cases vary, from 1% to 20%.
- Methods to minimize stress: lighting, ventilation, and mirrors
Pregnancy and MRI:
- MRI is usually safe during pregnancy
- First-trimester MRIs are generally avoided unless medically needed
Acoustic Noise:
- MRI scanner noise is due to rapidly varying current

Quenching

Magnet quenches can last several days; avoid pressing buttons unless in an emergency
Only qualified service personnel should test the “Quench” button
Immediate medical attention is needed, then press the emergency stop button
Remove patient immediately

Laser Alignment Lights

MRI systems have alignment lights; avoid direct eye exposure
Instruct patients to close eyes when landmarking
Do not leave the laser beam on after positioning patients

Contrast Agents

Contrast and Kidney Function:
- Gadolinium-based agents enhance tissue visibility
- Risk to individuals with impaired kidney function; careful monitoring
Contrast Media Types:
- Positive relaxation agents (T1 agents): affect T1 relaxation, increase signal on T1-weighted images. (e.g., Gadolinium)
- Negative relaxation agents (T2 agents): affect T2 relaxation, reduce signal on T2-weighted images. (e.g., iron oxide)

Gadolinium

Gadolinium Properties:
- Paramagnetic agent with large magnetic moment
- Shortens T1 relaxation times, increasing signal intensity on T1-weighted images
- Cannot be excreted by the body; long-term side effects
Gadolinium Side Effects:
- Slight transient increase in bilirubin and blood iron
- Mild transitory headaches
- Nausea
- Vomiting
- Hypotension
- Gastrointestinal upset
- Skin rash
Gadolinium Contraindications:
- Hematological disorders
- Sickle cell anemia
- Pregnancy
Gadolinium Administration:
- Effective dose is 0.1 mmol/kg body weight (approximately 0.2ml/kg)

Clinical Applications of Gadolinium

Tumor pre- and post-surgery
Pre- and post-radiotherapy
Infection
Infarction
Inflammation
Post-traumatic lesions
Post-operative lumbar disc
Breast disease
Prostatic disease

Iron Oxide

Shortens relaxation times of nearby hydrogen atoms
Reduces signal intensity in normal tissues
Used as a T2 enhancement agent
Potential for signal loss on proton density and heavily T2WI images

Iron Oxide Side Effects

Back, leg, and groin pain (mild to severe)
Head and neck pain
Digestive side effects (nausea, vomiting, diarrhea)
Anaphylactic reactions and hypotension (less common)

Iron Oxide Contraindications

Allergy/hypersensitivity to iron
Discoloration of skin due to extravasation

Iron Oxide Administration

Recommended dose: 0.56 mg per kg body weight
Administered as an IV infusion over 30 minutes (e.g. 0.56 mg of iron per kg of body weight, using Feridex dilute in 100 ml of 50% dextrose)

Clinical Applications of Iron Oxide

Primarily used in liver imaging where normal liver is dark on T2WI and lesions appear bright.

Other Contrast Agents

Gastrointestinal Contrast Agents:
- Used to enhance bowel visibility
- Include barium, ferromagnetic agents and fatty substances
- Movement artifacts common
- Anti-spasmodic agents might decrease artifacts
- Could be used for lung perfusion (inhaled helium)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on MRI safety protocols and patient preparation steps. This quiz covers essential procedures, including checking patient identity, the removal of metal objects, and tips on managing patient anxiety. Understand the importance of preparing patients for a smooth MRI experience.