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Magnetic Resonance Imaging(MRI)

Below is the information about the side effects of MRI, comparison among different types of medical scanning procedures, the latest MRI technology and our clinic’s offerings.

MRI Uses

MRI gives clearer and more detailed images of soft tissue parts of the body than any other imaging methods and therefore is frequently used to assess areas such as the brain, spine, joints, heart, abdomen and blood vessels. Take cancer as an example. MRI can help detect the location and stage of the tumor and monitor the changes of the tumor before and after treatment, such as detecting the signs of spreading. The doctor will decide whether the patient is fit for an MRI scan. In general, an MRI scan takes approximately 30 minutes.

Due to the strong magnets used during the scan, patients must remove any metal from their bodies before getting scanned to avoid accidents. Patients with certain metal implants or fragments such as a cardiac pacemaker, metal spine device, aneurysm clips or hearing aid implants are strongly advised against undergoing the MRI examination. However, patients with dentures should be fine to proceed with an MRI scan.

What are the side effects of MRI?

Because MRI does not involve any ionizing radiation, there will be no risk of exposure to radiation during an MRI scan. In general, discomfort does not occur after getting an MRI assessment, although in some cases people might develop allergic reactions to MRI contrast dye.

MRI side effects | Allergic reactions to MRI contrast dye

Contrast dye is injected into a blood vessel and in general, it is very safe, though not every patient will need a contrast dye injection. Some people might develop allergic reactions to the contrast dye. About 1% of patients receiving an MRI scan may experience mild side effects such as itchy skin, nausea, pain in the injected area, or feeling cold or hot.

For more severe side effects, patients might experience bronchospasm and severely low blood pressure. Patients with severe kidney failure or who undertake hemodialysis might develop nephrogenic systemic fibrosis (NSF) as a result of the allergic reactions to contrast dye. Severe reactions can be fatal, although it would be extremely rare.

MRI side effects | Pregnancy

So far it remains unknown how MRI affects patients during pregnancy. In general, patients less than 12 weeks pregnant are not advised to get an MRI scan, while patients who are breastfeeding will not be affected by the MRI contrast dye. If a contrast dye injection is required for the scan, we advise that patients who are breastfeeding should prepare 2 days of milk in advance before the MRI scan. They can continue breastfeeding when the contrast dye is removed from their system through urine, which usually takes 24 hours.

MRI side effects | Anxiety

Conventional MRI machine might create noise which sometimes reaches to a high rate of 100 Hz/s, equivalent to the noises generated from a drill machine and high-speed train. The harsh and strong sound can create unease and anxiety in patients. Besides, children or patients with claustrophobia might feel scared and experience a choking sensation after getting inside the assessment room and scanner. If this is the case, the attending doctor or radiologist will provide appropriate assistance, including allowing family members to keep the patients company during the assessment, and arranging a tour in the room and scanner for them before the actual scan takes place. Also, patients could get a small dose of sedatives if needed so that they can proceed with and complete the MRI scan under a relaxed state.

Are there any diagnostic methods that can replace MRI?

MRI is not the only imaging technique available for cancer scanning. There are various imaging procedures with different benefits and uses. Patients should consult their doctor and pick the scanning method that fits their actual diagnostic needs.



Benefits:Generate detailed images of internal body structures

Cancer Treatment:Breast cancer screening and diagnosis, including 3D mammography.

Level of Radiation:Minimal level of radiation



Benefits :Detect the real-time changes in organs but with a decreased sensitivity for tissues like bones and a lower imaging resolution.

Cancer Treatment : Cancer scanning such as prostate ultrasound and bladder ultrasound.

Level of Radiation : No ionizing radiation

Computer Tomography (CT)


Benefits : Capture the details of internal structures from many angles and produce two-dimensional and three-dimensional images.

Cancer Treatment : Applied to various cancer diagnoses.

Level of Radiation :A higher level of radiation that X-Ray but there is a low-dose CT scan

For more information

Positron Emission Tomography/Computed Tomography(PET-CT)


Benefits : Generate three-dimensional colored images with accuracy further improved by CT and data.

Cancer Treatment : Applied to early-stage cancer detection, malignant tumor detection, cancer staging, tumor localization, treatment monitoring.

Level of Radiation : The latest AsiR low-radiation technology can reduce 50% of radiation doses than conventional PET-CT scan.

For more information

Magnetic Resonance Imaging(MRI)


Benefits : Produce detailed images of the soft-tissue masses and nerves.

Cancer Treatment : Detect the location and changes of the tumor.

Level of Radiation : No ionizing rediation

Non-invasive MRI machine – GE Optima MR450W GEM

Our clinic uses the non-invasive MRI machine, GE Optima MR450W GEM, that combines the benefits of wide-bore MRI technology and cancer treatment planning, enabling precise targeting of tumors and a reduction in side effects. It also comes with advanced noise reduction technologies which provide comfort to patients during the scanning without compromising image quality.

This new system entails a wide range of cutting-edge features, such as magnetic resonance elastography (MRE) which measures the stiffness of liver tissues, elucidating liver conditions in more detail than any other conventional imaging techniques without the need of an invasive assessment. Another feature is IDEAL IQ which delivers whole liver 3D coverage and provides a non-invasive, quantitative assessment of triglyceride fat content in the liver, facilitating the monitoring of the changes of fat content in the liver.

HKIOC Services

HKIOC provides a wide range of services for medical assessment including imaging scanning and interventional radiological services. They are:

● Magnetic Resonance Imaging (MRI)
Positron Emission Tomography/Computed Tomography(PET-CT)
Computer Tomography(CT)
● Interventional radiology and digital subtraction angiography
● 3D mammogram
● Ultrasound
● X-Ray
● Blood test

Contact Us

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