Department of Radiology
School of Medicine Queen's University
 

MRI General Info & MRI Safety

Radiology Residents orientation for MRI

 

There is currently one MRI machine for the whole KHSC.

It’s a 1.5 Tesla Siemens Avanto machine that is capable of most routine MR exams but also a few more advance MR applications such as pediatric Neuro imaging, Cardiac imaging, Breast imaging, MR Enterography.

The current hours of operation are from 7AM to 12AM during weekdays,

and from 7AM to 7PM during weekends.

Outside these hours an MR technologist is ON CALL for specific MR emergencies that cannot wait to be done during normal hours.

MRI techs ext. 2796

MRI tech on call pager #650-3661

The MRI machine is always in high demand and most of the scans that are done during the day are booked/scheduled Outpatients.

There are allocated “open time slots” every day (including weekends) for Inpatients and Emergencies.

During the day all scans are coded by a staff radiologist, who  also determines if an injection of gadolinium is necessary.  The standard dose of gadolinium is 0.1ml/kg. 

The radiologist also determines the urgency of the MR scan based on a 1 to 4 scale.

#1 meaning 24 hours, #2 in 48 hours, #3 10 days, #4 Beyond 10 days

The MR techs will get inpatients scanned according to the urgency score and available open time.

In the evening when taking over for the day Rad it’s a good practice to check in with the techs and they will let you know if there are any emergencies or pending Inpatient exams.

MRI booking clerks are in charge of scheduling all the Outpatients including outpatient emergencies or referrals from other centers.

 MRI bookings ext. 2786

 

MRI protocols are arranged by anatomy and/or specialty as follows:


Neuro

-        Brain

-        Spine

-        Neck soft tissue

-        Brachial, lumbar plexus

-        MRI angiography of brain, spine, neck

Body:

-        Abdomen (liver, pancreas, kidneys, adrenals, spleen)

-        Pelvis based on female or male anatomy

-        Enterography

-        Rad check cases

-        MR angiography of abdominal vessels

MSK:

-        Individual joints and certain bilateral studies

-        Long bone/extremities

-        MSK pelvis

-        Peripheral runoff

Chest:

-        Cardiac MRI

-        Chest soft tissue

-        MR angiography of Aorta and thoracic vessels

Breast:

-        MR Breasts routine or implants

-        MR Breast biopsy

Vascular:

-        MR angiography of various anatomy

For queries and/or a detail list of the MR protocols please contact the Senior MRI tech, Tudor Chibacu.

  

MRI scans in general tend to be a lot longer then a CT exam. This is primarily due to the way MRI images are acquired but also patient preparation plays a big role in the total duration of an MRI scan. There is of course the screening of the patient, clearing of all implants (if present). Patient needs to change, remove all jewellery  and metal accessories. If monitored they will be switched to an MRI safe monitor.

 

A few examples of estimated scan times (the duration of the actual MRI exam, excluding patient preparation) at KGH:

 

DWI brain only – 5 min

Tumor brain – 25 min

Cauda equina (L-spine) – 20 min

Trauma spine (one region, non Gado) – 30 min

Whole spine routine (Cord Compression) – 30 min

Whole spine with Gado (infection, tumor) – 60 min

MRCP – 25 min

Cardiac MRI (Gado) – 60+ min

 

Major MR safety concerns

 

Cardiac pacemakers, ICD’s or Loop Recorders.

          Even if MRI conditional, this type of devices and their attachments still need to be checked by the Device Clinic for MRI compatibility.

In the case of pacemakers, the patient will need complete monitoring during the MRI exam.

 

Aneurysm Clips

          We require make and model of the clip in every case, no matter what type of scan the patient is having.

 

Otologic Implants

          Make and model of the implant needs to be provided

 

Genital Prosthesis

          Make and model is needed if penile prosthetic

 

Electronic or programmable implanted devices

          Make and model for all Programmable valves, Neurostimulators, Pumps, etc.