Magnetic Resonance Imaging (MRI)

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Overview

Magnetic resonance imaging (MRI) is a non-invasive medical imaging technique to generate images of the organ of interest. MRI scanners use strong magnetic field to align the water protons which generates a resultant bulk magnetization vector, radio waves to flip the resultant magnetic vector, and field gradients to spatially localize the signal which in turn generates images of the organs in the body.

Applications of MRI

MRI has a very wide range of applications in medical imaging. MRI is used to perform structural and functional imaging to understand the physiological processes of the body in both healthy and disease condition. The structural abnormalities associated with any disease condition e.g., tumor can be visualized with MRI images, which helps to perform image guided surgery. MRI is also used to perform functional imaging (fMRI) to understand the function of the brain as it responds to external stimuli and the passive activity in a resting state as well.

MRI Magnet

Our centre is equipped with the state-of-the-art Siemens 3Tesla PRISMA scanner with 60cm bore size. The scanner is equipped with 128 receiver channels which results in high signal-to-noise ratio images acquires with fast acquisition speed. The magnetic field stability over time is less than 0.1ppm/h. The scanner is equipped with 5th generation active shielding technology with counter coils. The External Interference Shielding (EIS) provide continuous compensation and automatic external magnetic field interferences during acquisition. The shim system comprises of three linear and five non-linear channels and a 3D patient specific automatic shimming.

Siemens 3Tesla PRISMA Scanner

 

RF Coils

We have a variety of RF coils suitable for imaging different parts of the body.

  • Body 18
  • Head 32
  • Head/Neck 20
  • Head/Neck 64
  • Spine 32
  • Flex large 4
  • Flex small 4
  • TxRx Knee 15

Gradient System

The scanner contains actively shielded whole-body 80mT/m gradient coil system. The gradient coils are water-cooled and with 100% duty cycle.

Methods 

The scanner contains a variety of methods comprising of both spin echo (SE) and gradient echo (GE) family of sequences.

  • SE
  • TSE
  • HASTE
  • SPACE
  • FLASH
  • VIDE
  • MEDIC
  • DESS
  • TurboFLASH
  • FISP
  • EPI
  • ToF
  • PC
  • CV/BEAT

Patient comfort

The inner diameter of the magnet is 60cm, with in-bore lightning, ventilation and intercom.

Functional Imaging

Functional magnetic resonance imaging (fMRI), is a technique for measuring brain activity. It works by detecting the changes in blood oxygenation and flow that occur in response to neural activity – when a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area. fMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.

Our MRI facility contains the hardware & software for performing task based functional imaging. The fMRI kit comprises of the following:

  • MR-compatible LCD monitor for visual stimuli
  • MR-compatible headphones for auditory stimuli
  • MR-compatible response boxes and interface
  • MR-compatible eye tracking camera
  • Stimulus PC

Eye Tracker

Our MRI facility have ViewPoint Eye Traker with intuitive user interface, Pupillometry, built-in state Machine for experimental control. It provides a complete eye movement evaluation, including Fixation, Saccade, drift classification, region of interest events, integrated stimulus presentation, simultaneous eye movement and pupil diameter monitoring & SDK for interfacing with other applications. Our EyeTracker system is compatible is with all the MRI head coils available in our MRI facility.

Image processing software

The data generated in scanner can be exported in DICOM format and be processed according to the user’s requirement. The Syngo.via, workstation, a Siemens post-processing software, is used for dedicated image processing purposes. In addition, the image processing is performed in 3rd party software viz.,ImageJ, Matlab, DTIStudio etc.

Data Storage & Management

The data generated per acquisition in MRI is of Gigabytes. The data generated is locally stored in the control work station, and periodically will be transferred to our Network Attached Storage (NAS). The total capacity of NAS is about 50TB. The total storage has been fragmented to about 25TB for MRI and 20TB for MEG respectively. The MRI data acquired is stored in the Siemens scanner for a brief period of time. For MRI data archiving we have Syngo.plaza storage (Siemens secondary storage system), in addition to NAS. All the storage and back-up systems are connected by local network to ensure smooth & safe data transfer and storage. The NAS has been configured (PACS) to be compatible to store the MRI data in the Siemens format. The handling of data and its delivery to the collaborators are followed according to the SOP.

Mock MRI scanner (0 Tesla)

A mock MRI scanner is generally used to assist subjects to experience the real MRI scanning process. The mock scanner has no magnetic field, but can simulate the real MRI scanning experience, by generating scanning noises & vibrations, to the subjects, thereby preparing the subjects for the real MRI scanning process. CoNiC has stationed a mock scanner with the purpose of training the subjects prior to the real MRI scanning. Further the mock scanner facility is used for demonstration, educational purposes and also for claustrophobic subjects.

 

Siemens 0Tesla Mock Scanner

 

​​Visual and Auditory Stimulus

Stimulation Equipment

To deliver stimulation our MRI facility is equipped with a stimulation workstation in which various built-in paradigms are present. Also the stimulation software can be used to design and develop used defined paradigms. A MRI compatible monitor behind the scanner is used to deliver the stimulation to the subject. A MRI compatible head phone is used to deliver the auditory stimulation to the subject.

A hand gripping in air
​​Response Grips

Response Equipment

Two response grips are used to receive any response from the subject.

Processes

Workflow for Anatomical MRI
Anatomical Workflow
Workflow for Functional MRI
Functional MRI Workflow
A map of cognitive tasks

MRI: A Safe Environment

MRI scanning has no risks associated with it to a general subject if an appropriate safety guideline are followed.

We are here to provide you the safest environment and make you aware about the potential safety hazards.

Getting Screened for Scan

Precautions for Entering MRI Scanning Room

MRI Safety Video

Videos for MRI safety and understanding the basics of MRI can be accessed from the following link provided by Siemens:


Safety Incharge

Please contact our safety in-charge regarding safety briefings and other safety issues:

 1. Dr. Sundramurthy Kumar, CoNiC Safety In-charge
     Email: s_kumar@ntu.edu.sg ; Phone: (65) - 6904 1185


 2. Dr. Sini Mathew, Assistant Director, Health & Safety, LKCMedicine 
     Email: sinimathew@ntu.edu.sg ; Phone: (65) - 6592 3209