Combined technologies revolutionising diagnostic imaging
16 January 2006
New technological advances in diagnostic imaging have resulted in a
highly sophisticated technique called fusion imaging that uses special
software to combine both anatomical and functional images. This novel
technique provides previously unattainable levels of precision in detecting
numerous conditions such as tumours, Alzheimer's disease and neural
"Hybrid imaging modalities such as positron emission tomography/ computed
tomography (PET/CT) and single photon emission computed tomography/CT
(SPECT/CT) are revolutionising the field of diagnostic imaging," notes
Technical Insights Research Analyst Preethi Vaidyanathan. "Several PET/CT
devices with different features have already been introduced and are
Combined PET/CT delivers better results than PET or CT, because it offers
more accurate localisation of flurodeoxyglucose (FDG) uptake, distinguishes
pathological from physical uptake and enables improved monitoring treatment.
Other significant advantages of PET/CT imaging include better diagnostic
accuracy, treatment planning and response evaluation as well as enhanced
guided biopsy methods. This imaging modality is particularly useful for new
indications and applications that cannot be satisfactorily performed with
individual PET or CT and retrospective image alignment.
Combined SPECT with high-powered CT scanners are finding application in
multiple new research and clinical arenas such as in vivo small animal
studies and CT angiography in the emergency department. Researchers are
already investigating several new tracers specifically to target cancers of
the brain, thyroid, prostate, breast, lung, ovaries, kidneys, and liver as
well as diseases of the heart and bones.
"By combining high-speed CT scanners with SPECT's highly accurate
definition of disease processes, anatomical mapping and localisation can be
enhanced,'" says Ms. Vaidyanathan. "Most significantly, CT attenuation
correction greatly reduces the problems of distortion and degradation that
typically occur with radio-nuclide-based methods."
Combined SPECT/CT has also proved to be highly effective in examining
patients with neuroendocrine tumours. Researchers from the University di
Roma Tor Vergata, Italy, have undertaken a study in an attempt to identify
the future applications of SPECT/CT imaging.
The results of this study revealed that such hybrid imaging can increase
the specificity of SPECT alone, thus influencing choice of treatment and
avoiding unnecessary therapy owing to the exclusion or the identification of
previously unknown malignant lesions.
Researchers are now evaluating the possibility of combining SPECT and CT
data for oncology applications. While the combination of FDG-PET and CT data
has emerged as a potent strategy for cancer diagnosis, staging, and
follow-up, SPECT/CT also has great potential in oncological imaging.
For instance, SPECT/CT can provide an excellent alternative in cases
where institutions cannot afford FDG, which is expensive and has a short
life. SPECT tracers are often more cost-effective, easier to obtain and in
certain tumours, more accurate than FDG.
Researchers at the University Hospital of Zurich attempted to compare the
accuracy of contrast-enhanced material helical CT alone with that of
coregistered PET/CT and coregistered SPECT/CT. This was to determine how
these different modalities fared in detecting bone invasion in patients
scheduled to undergo surgery.
The outcome of their research suggests that contrast-enhanced CT and
PET/CT are better than SPECT/CT for identifying the invasion of the
mandibular and maxillary bones in patients with oral cavity cancers. While
the performances of PET/CT and contrast-enhanced CT were comparable with
each other, PET/CT had the highest sensitivity and contrast-enhanced CT
scored over all other imaging tests in terms of the highest specificity.
At the University Hospital Charite in Germany, researchers experimented
with using SPECT imaging with a synthetic amino acid derivate,
iodine-a-methyl tyrosine (IMT), as an alternative to MET-PET. They found
that this combination had great clinical potential in diagnosing recurrent
head and neck carcinoma. However, researchers sometimes faced an obstacle in
interpreting metabolic data due to the lack of anatomical information.
Emerging Technology Developments in Fusion Technology for Diagnostic
Imaging is part of the Technical Insights Healthcare vertical subscription
service of Frost & Sullivan, and provides a comprehensive overview of
important advances in fusion technology in medical diagnostics. It focuses
on the most promising areas and technologies and provides detailed coverage
of key participants and their research developments.
For more information see
http://technicalinsights.frost.com or contact Radhika Menon Theodore,
European Corporate Communications, Frost & Sullivan, at