of a new era
The incredibly fast 64-slice Computed Tomography scanner is being
hailed for initiating a new age of medical imaging. This incredible
piece of technology is revolutionising diagnosis in cardiology,
oncology, neurology and may other areas. Middle East Health looks
at four of these scanners.
64-slice Computed Tomography (CT) scanner, the latest generation in a
line of CT scanners stretching back about 15 years, is revolutionising
non-invasive diagnosis. These machines, as if in a world of science
fiction, can scan the whole body in seconds and provide incredibly sharp
3D images of any organ.
The new 64-slice scanner is changing the face of diagnosis. The
scanner’s ability to quickly and non-invasively spot small tumours, in a
check on the lungs for example, or plaque in the case of cardio-vascular
disease, is making it the preferred option for diagnosis by an
increasing number of physicians, rather than the invasive,
time-consuming and more risky diagnostic procedures that have been used
The invention of computed tomography is considered to be the greatest
innovation in the field of radiology since the discovery of x-rays. This
cross-sectional imaging technique provided diagnostic radiology with
better insight into the pathogenesis of the body, thereby increasing the
chances of recovery. In 1979, GN Hounsfield and AM Cormack were awarded
the Nobel Prize in medicine for the invention of CT.
CT is now one of the most important methods of radiological diagnosis.
It delivers non-superimposed, cross-sectional images of the body, which
can show smaller contrast differences than conventional x-ray images.
This allows better visualisation of specific differently structured
soft-tissue regions, for example, which could otherwise not be
Since the introduction of spiral, or volume CT, in the 1990s, computed
tomography has seen a constant succession of innovations. The
development of slipring technology allowed for a continuously rotating
gantry – the prerequisite for spiral CT.
The first multi-slice CT scanners were in operation by the early 1990s.
The original Elscint-Twin scanner, introduced in 1994, allowed
acquisition of two images simultaneously through a dual detector array.
The four slice scanner was introduced in 1998. With the introduction of
the 16-slice scanner, taking a scan of the heart, for example, would
take 20 to 25 seconds to collect all the data. However, these images
were still subject to motion artifacts, reducing their diagnostic
clarity, due to the patient having to breathe during the scan period.
But with the introduction of the 64-slice scanner nearly all patients
can be scanned with very high resolution in just a few seconds. Scan
times are generally between only five and thirteen seconds. This means
that even patients with severe pulmonary disease and congestive heart
failure can hold their breath for the length of the scan period which
results in minimal or no motion artifacts in the image.
The multi-detector scanners can be packed less than a millimeter apart
and take less than half a second to circle the body. So, a 16-slice
scanner can cover 8mm to 12mm in one pass or about 2.5 centimetres a
second. A 40-slice scanner collects images covering 20mm to 32mm in a
single pass and a tightly packed 64-slice device can cover about 40mm at
a pass, which takes 0.4 seconds.
At that rate, a 64-slice scanner can gather a high resolution image of a
heart, brain or a pair of lungs in about five seconds. A scan of the
whole body, (in search of a blood clot, for example, that has become a
source of emboli) takes about 30 seconds.
The beating heart
The technology has been particularly
exciting for studying the beating heart, providing the first clear
non-invasive images of the heart and its major vessels. The scans can be
timed to use only images gathered between contractions, so that the
heart and its vessels can be seen without the blurring caused by motion.
The scanners are also beginning to have an impact on cancer diagnosis
and treatment. Nearly 60% of CT scans at the University of Chicago
Hospitals in the United States are done for cancer. The hospital was the
first in the US to install Philips’ Brilliance 64-slice CT scanner
earlier this year. The speed and precision of these new scanners not
only improves the image quality, but also "lets us look at dynamic
processes", Michael Vannier, MD, professor of radiology at the
University of Chicago said.
"Instead of just monitoring changes in tumour size, we can watch the
perfusion of a contrast agent as it moves toward, around and through a
tumour," he said. "This can provide an early view of how a patient is
responding to therapy. It helps us predict, rather than simply describe
responses to treatment."
In fact, according to a University of Chicago Hospitals spokesperson
these scanners have already provoked "turf" battles between radiologists
and cardiologists who perform diagnostic angiograms – until now the gold
standard for assessing the coronary arteries. The best multidetector CT
scans can rival angiography for detail and are quicker, more convenient,
less expensive and safer than an angiogram, as well as exposing the
patient to less radiation.
"We've already switched from catheter-based to CTbased imaging in the
brain," said Dianna Bardo, MD, assistant professor of radiology at the
University of Chicago. "The heart may come next."
Other promising indications for multi-slice scanners include evaluation
of plaque within the carotid arteries (five to eight seconds), searching
for pulmonary emboli (five seconds, less than an easy breath hold),
coronary artery imaging (10 seconds, including distal segments and
multiple arterial branches).
medcompare.com points out that despite the promise of 64-slice CT in
non-invasive cardiac diagnostics, some cardiologists have expressed
concern in their widespread use. Is the dose of x-ray radiation safe to
use on everyone, in other words as a screening test, they ask?
Multi-scan CT delivers increased levels of focused radiation compared
with single slice CT and although these slightly increased doses are
justified for patients with existing or symptomatic disease, they may
not be appropriate for everyone, they warn.
Nonetheless, the technology is a major advance and continues to be
refined. Prototypes for 128-slice and even 256-slice scanners are under
development. Clinical use of multi-slice CT is increasing and the 64-
slice cardiac CT heralds a new age of non-invasive cardiac imaging.
64-slice CT scanner
The Aquilion 64 is built on Toshiba's unique 64-row Quantum detector,
volumetric imaging capabilities and advanced software applications.
the heart of the Aquilion 64 is its superior multi-detector design, that
produces high-speed, high resolution imaging with the best low contrast
resolution at the lowest dose. The Quantum detector enables the Aquilion
CT scanner to acquire 64 simultaneous slices of 0.5 mm with each 400-
millisecond gantry revolution. The result is precise isotropic imaging
of any region of the body during a breath-hold under 10 seconds.
Toshiba's CT technology offers true isotropic voxels, which greatly
enhance most clinical studies, including examinations of the lungs,
joints, extremities and CT angiography.
Isotropic data sets also markedly improve the quality of MPR and 3D
reconstructions, which aid the radiologist not only in diagnosis, but
also in managing the huge amount of information generated by multi-slice
Toshiba has succeeded in developing isotropic imaging based on the
standards of 0.5mm slices for the head and one millimetre slices for the
abdomen. Applications for 0.5mm slice scanning are studies of the
cerebral circulation, lungs, spine, joints and extremities.
The 64-detector scanners naturally make more efficient use of the x-ray
beam, however with the corresponding increase in CT scans from
multi-detector CT comes a concern about minimising dose for every
examination. Aquilion systems are designed with tubes that reduce
off-focal xrays and detectors that provide excellent image quality at
further enhance patient safety, Aquilion 64 incorporates several
additional features to assure dose effective imaging.
Shaped filters modify the beam profile to automatically reduce dose
based on exam type. This is particularly beneficial for paediatric and
Quantum denoising software lets users balance the trade-off between dose
level and image quality. Operators can either lower the dose by as much
as 50% and maintain image quality, or keep the standard dose and improve
Toshiba’s ‘Sure Exposure’ ensures optimum image quality at minimum
patient dose, by adjusting the tube current during scanning. Often
reducing total dose by up to 40% per patient, it is especially valuable
in paediatric examinations to ensure children receive the lowest
acceptable dose, every time.
Raster Artifact Suppression Protocol (RASP) reduces streak artifacts
from high-absorption areas like the shoulders and pelvis, and minimises
the need to increase dose to compensate for absorption.
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Somatom Sensation 64 was first introduced at the Radiological Society of
North America (RSNA) 2003. Sensation 64 offers clinicians the peak of
clinical performance. Empowered by the Siemens unique Straton tube and
z- Sharp Technology, the Somatom Sensation 64 enables the user to
routinely achieve unprecedented diagnostic detail with the industry’s
highest isotropic resolution of below 0.4mm and fastest rotation time of
up to 0.33 seconds. By utilising the most powerful advanced
applications, the user can image the smallest pathology and finest
anatomical structures in just a few seconds.
The Somatom Sensation also utilises the newly developed Speed4D
technology which has changed CT tube design, dose optimisation and
workflow management to enable the automation of complex imaging
processes while providing consistent, high quality results in a minimum
amount of time. Siemens’ ‘CARE Dose4D’ automatically adjusts the tube
current in real-time to reduce dose up to 66% while maintaining optimal
image quality. ‘WorkStream4D’ directly generates diagnostic images in
any desired plane, thus eliminating time consuming, manual
Siemens Navigator is designed to give the clinician intelligent,
reliable workflow for data acquisition, image reconstruction and routine
post-processing at the CT scanner. Built on Siemens’ unique ‘syngo’
platform, the Navigator is intuitive and user friendly. With the
integrative WorkStream4D concept, the Navigator provides unmatched speed
and efficiency, facilitating simultaneous acquisition and reconstruction
at a single workplace. With access to a comprehensive portfolio of syngo
clinical applications, the Navigator helps the clinician achieve
seamless integration of their diagnostic workflow.
Siemens Medical Solutions says it has the world's largest installed base
of 64-slice CT technology in clinical routine worldwide. Two hundred
64-slice CT systems have been installed, 80 of which include the Somatom
Sensation Cardiac 64 in hospitals' cardiovascular departments or
institutions specialised in the diagnosis and treatment of
The Somatom Sensation Cardiac 64 is Siemens’ latest contribution to CT
technology. Siemens says: “With the world's fastest gantry rotation
speed of 0.33 seconds, the Somatom Sensation Cardiac 64 routinely
achieves a temporal resolution of 83 milliseconds, and thus facilitates
scanning of patients even with higher heart rates, virtually freezing
the heart's motion. Utilising Siemens' unique ‘z-Sharp’ technology, the
scanner delivers optimal image quality with a routine isotropic
resolution of below 0.4mm. This unique temporal and isotropic spatial
resolution, available in all routine and cardiac modes, allows for
optimal evaluation of peripheral segments of the coronary arteries,
including plaque evaluation, and improves follow-up assessment of stent
patency with high confidence.
“The combination of the fast rotation speed with 64- slice acquisition
also enables an electrocardiography (ECG) gated coverage of the entire
chest in a short 15- second breath hold. For the first time, this CT
performance allows for the evaluation of the most common causes of acute
chest pain with a single scan. A routine scan of the coronary arteries
only takes about eight seconds.”
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GE’s Lightspeed VCT
The LightSpeed VCT is GE’s latest innovation in CT technology. VCT means
The hallmark of this noninvasive imaging system is GE’s new ‘V-Res’
detector with its ability to deliver wide anatomical coverage and high
This unprecedented coverage speed allows clinicians to capture whole
organs in a second, the heart in five beats, or go head to toe in under
In a single rotation, the system creates 64 credit card-thin images,
totalling 40mm of anatomical coverage and producing a hi-resolution 3D
view of the patient’s anatomy.
is clearly the beginning of a new imaging era,” said W Dennis Foley, MD,
chief of Digital Imaging at Froedtert Hospital and professor of
radiology at the Medical College of Wisconsin, US. “This system provides
unprecedented image quality almost instantaneously, which should provide
significant impact in cardiovascular medicine and trauma. Though its
impact may be most significant in trauma and cardiovascular medicine,
the LightSpeed VCT also should improve imaging in neurology, oncology
and other fields.”
With breakthroughs in technology, comes the opportunity for new and
dynamically enhanced procedures, such as:
5-Beat Cardiac – Heart motion has historically made CT
cardiovascular scans challenging and prone to motion artifacts. The
LightSpeed VCT will enable physicians to secure extremely high-quality
images of coronaries at submillimetre resolution in only five beats of
the heart. This capability will potentially make diagnostic evaluation
of arterial stenosis faster and less invasive than catheter angiography.
Triple RuleOut – Patients exhibiting acute chest pain in the
emergency room may be able to be diagnostically scanned quickly and
noninvasively, using the LightSpeed VCT, for evidence of heart attack,
pulmonary embolism or aortic dissection, the three most life-threatening
causes of chest pain, all in a single scan. A doctor’s ability to
identify the cause of acute chest pain and eliminate unnecessary
hospital stays and missed diagnoses is invaluable.
Stroke WorkUp – Once a stroke occurs, it is commonly believed
that treatment must be delivered within an hour or less to ensure the
best outcome for the patient. Current diagnostic imaging procedures are
complex. LightSpeed VCT offers the speed and resolution required for
rapid examination of blood vessels in the brain (perfusion studies),
enabling doctors to make a quick diagnosis of stroke and extent of
damage, and may help make this complex procedure easier and more
Specifically, the LightSpeed VCT covers 4cm of patient anatomy per
rotation, gathering 64 slices at 0.625mm (about the thickness of a
credit card). Gantry rotation speed is less than 375 milliseconds or
approximately 2.5 to 3 rotations per second.
comes complete with GE’s Xtream FX. Xtream FX is the second generation
of GE’s Xtream workflow technology, which provides imaging departments
the ability to keep pace with the large volume of data generated by MDCT
systems. A tool such as Direct Multi-Planar Reformat (DMPR) allows
customers to improve interpretation efficiency, and provides views that
are more familiar to referring physicians and surgeons. Xtream FX adds
more “effects” to GE’s scalable Xtream reconstruction engine, which
revolutionized workflow design with increased speed, image quality, and
In addition to its capabilities as a stand-alone technology, GE designed
the LightSpeed VCT to easily integrate with its positron emission
tomography (PET) technology. This fusion will marry the highspeed,
high-resolution capabilities of GE’s volumetric CT with the metabolic
and physiologic capabilities of its industry leading PET.
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Philips’ Brilliance 64
introduced the new Brilliance CT 64-channel scanner at RSNA 2004. This
new scanner delivers large coverage, thin-slice acquisition capabilities
to the full 40mm width of the Brilliance CT detector by increasing the
number of simultaneously acquired data acquisition channels to 64.
With the Philips Brilliance 64-channel system, clinicians can easily
capture rich visual details, cover a large area of the body, in less
time, all with high levels of patient comfort. All Philips Brilliance CT
systems are designed to improve the patient experience as well as that
of the operator; all aspects of the system are optimised for
ease-of-use, low dose and feature new visualisation methods and Philips’
‘Guided Flow’ concepts supporting diagnostic confidence. The 64- channel
configuration also provides advanced pulmonary imaging, multiorgan
trauma evaluation and low-dose paediatric applications as well as in the
areas of cardiovascular CT and virtual colonoscopy.
Philips says the its Brilliance 64 CT is designed for leading edge and
research-oriented institutions that want to conduct the most advanced
studies. The company says the new scanner will expand clinical
boundaries through applications, such as extended coverage brain
perfusion, that will position CT as a modality of choice in stroke
evaluations. Philips Medical’s ‘DoseWise’ design delivers optimal dose
efficiency without compromising image quality.
Following extensive collaboration with their customers Philips developed
the Brilliance CT family – 6, 10, 16, 40 and 64 channel. In addition
Philips developed two specialty systems: one designed specifically for
oncology marking, acquisition and scanning and the other for
non-invasive cardiovascular assessment.
Philips’ user environment is called the Brilliance Workspace.
Brilliance Workspace is:
- designed to maximise the ability of advanced CT systems without
compromising their usability.
- specifically developed to manage the enormous datasets generated by
largevolume CT acquisitions.
- rich in clinical applications that boast time-saving features designed
to eliminate the traditional constraints which hamper workflow and
quality of care.
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