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syngo.via is intelligent.
Quantify the invisible.
The software1 guides you through the entire workflow - it automatically pre-processes images and delivers powerful quantitative reading functionality.
Due to its unique capability of imaging and quantifying biological processes, molecular imaging is the modality of choice for many complex clinical questions in the areas of oncology, cardiology and neurology.
To fully exploit the quantitative capabilities of recent scanner innovations, such as Biograph™ mCT, advanced applications are available from Siemens that can be configured on syngo.via.
The most recent innovations allow for confident and efficient quantitative assessment of:
- blood flow in cardiology
- therapy response in oncology
- dementia in neurology
The complete overview of molecular imaging applications on syngo.via can be found under Technical Details.
With its unique capability to accurately detect metabolic changes before anatomical changes are visualized, PET/CT has become instrumental for early detection and staging, as well as therapy response assessment. Quantitative therapy response criteria are well established in CT with RECIST and WHO. In PET, current practice incorporates SUVmax as the major quantitative parameter. However, since SUVmax is essentially a single voxel volume of interest (VOI), it is subject to larger statistical variation compared to other SUV measurement criteria. SUVpeak offers a metric that is reproducible while also being robust to noise.
SUVmax is subject to significant statistical variation, where SUVpeak is the mean value of the voxels within a fixed sphere of one cubic cm volume, centered on the hottest area of the tumor. This makes it close to SUVmax in terms of its representation of the maximum tumor metabolism, yet it avoids the statistical fluctuations of SUVmax due to incorporation of a larger number of voxels within the hottest tumor area. SUVpeak is easy to obtain in routine clinical use; the SUVpeak alogorithm automatically identifies the hottest 1 cm3 sphere within a VOI, which ensures reproducibility.
The illustration shows individual voxel SUVs in a lung tumor before and after therapy. The pre-therapy and post-therapy SUVmax evaluation shows a 17.6% decrease in metabolic activity, which reflects inadequate tumor response. The SUVpeak quantification, based on the average of multiple voxels involving the region with highest uptake, shows a more pronounced tumor response with a 30.3% decrease in metabolic activity.
syngo.via provides a comprehensive reading environment for hybrid oncology follow-up. Up to 8 hybrid examinations can be visually compared and quantified at the same time. For increased productivity, a single-click hybrid quantification tool provides the user with both CT and PET metrics, including SUVpeak, SUVmax, SUVmean, RECIST 1.0 or 1.1, WHO and volume. The quantitative segmentations can easily be exported to be used in radiation therapy planning.
The sequential 18F-FDG PET study illustrates the variation between SUVmax and SUVpeak for evaluation of therapy response. Decline in SUVpeak is more pronounced compared to SUVmax.
- Factors introducing inter- and intra- reader variability
- Depending on at least one normal reference region
- Similar impression for normal and abnormal balanced perfusion
- Features enabling accuracy and reproducibility
- Absolute quantification of myocardial blood flow
- Quantitative values for normal and low levels
Quantification of SUV ratio for Amyloid Plaque
Several studies have illustrated that in certain clinical cases, visual assessment alone may lead to inconclusive or false reports which can be a source of risk to practices and patients. In specific, borderline cases and those where the intensity of amyloid uptake is insufficient, it may become challenging to accurately interpret based on visual assessment alone.
Dr. Adam Fleisher and his fellow researchers developed what came to be known as the Fleisher Method which established criteria to determine amyloid burden. This reference model compared against autopsy identified six optimal zones to evaluate pathological levels of amyloid plaque burden. It also identified threshold between normal and abnormal uptake that were researched in diseased and healthy patients
Siemens application may improve reproducibility and calculations of SUVr compared with only visual read.2
- Factors that may introduce inter- and intra- reader variability
- Manual identification of brain regions
- Manual measurement of SUV averages
- Manual computation of uptake ratios
- Features that may improve reproducibility
- Automatic mapping of brain regions
- Automatic calculation of regional SUV averages
- Automatic computation of uptake ratios
1syngo.via can be used as a stand-alone device or together with a variety of syngo.via-based software options which are medical devices in their own right.