imaging-services

FAQs

List of Imaging Services

Computed Tomography (CT)

A Computed Tomography (CT) Scan examination is an x-ray procedure performed using a computerised x-ray scanner that resembles a “doughnut”. Images are produced using a narrow beam of x-rays that are rotated around the region of your body to be examined. You will be asked to lie down on the CT scan table. During the CT procedure, the CT scan table will move in and out of the scanner several times to capture images of your body.

Some of the specialised CT scan examinations performed in SGH neuroradiology include:

Dual Energy CT

Dual energy CT is a CT technique that uses two different x-ray energy spectra to acquire images of the same region, to make use of the different attenuations of tissues at different energy levels.

There are various applications of dual energy CT in neuroimaging, for example, automated bone removal in CT angiography, differentiation of iodine and haemorrhage on CT brain, as well as differentiation of hyperdense and enhancing lesions in the head and neck.

4D Parathyroid CT

4D Parathyroid CT is a valuable imaging tool for the purpose of identifying abnormal parathyroid glands for the pre-operative planning of parathyroid surgery. Intravenous iodine-based contrast is used and images are obtained at the CT scanner at specific times, to make use of the different uptake of contrast by the parathyroid gland at different time points.

Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is a versatile medical diagnostic technique used to create thin section images of the body using a magnetic field and radio waves. It does not use X-rays and is completely non-invasive.

SGH is equipped with a fleet of high-end MRI scanners with field strengths of both 1.5 Tesla and 3 Tesla. The specifications were chosen to ensure a wide range of examination capabilities, from routine scans like MRI brain or spine to advanced studies such as MRI perfusion and functional MRI. The service is augmented by a 3D laboratory where complex three-dimensional and advance neuroimaging data is post-processed to enhance their diagnostic value.

Examples of some specialised scans performed are:

MRI Perfusion and Spectroscopy

MRI perfusion using dynamic susceptibility contrast (DSC) and dynamic contrast enhanced (DCE) techniques is used in SGH to allow us insight into the perfusion of tissues by blood.

With post-processing in our 3D laboratory, these perfusion studies are useful to be integrated to conventional MRI techniques, for scenarios such as identification of higher grade component in a diffuse brain tumour and differentiation of tumour recurrence and post-radiation changes, in which MRI perfusion can offer critical information for treatment planning.

Functional MRI (fMRI) and Tractography

Functional MRI (fMRI) of the brain is performed to locate the regions within the brain that control various parts of the body. This is done by getting the patient to perform simple movement or language tasks while the scan is on-going. Tractography is an imaging technique that maps the location and direction of fibre tracts in the brain. The localisation of these control centres and mapping of fibre tracts within the brain can aid in planning prior to brain surgery.

MRI Nigrosome

MRI nigrosome makes use of newly developed MRI techniques (neuromelanin sensitive sequence and susceptibility map-weighted imaging), together with morphological imaging to differentiate different types of parkinsonism. Increasing application is seen in the evaluation of parkinsonism and gait disorders.

MRI Vessel Wall Imaging

With advancement in MRI technology, there is enhanced ability to achieve high spatial and contrast resolution. MRI vessel wall imaging allows for assessment of thin arterial walls in the brain, beyond the luminal abnormalities depicted on angiographic imaging. It is particularly valuable in distinguishing various causes of intracranial arterial stenosis, such as atherosclerotic disease and vasculitis.