Diagnostic imaging  

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 disorders.

"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 available commercially."

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 rmtheodore@frost.com 

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