“This technology is here to stay”

Tobias Granberg is a research group leader at the Karolinska Institute and section head at the Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden. He leads the clinical implementation and technical developments of Karolinska’s NAEOTOM Alpha¹ photon-counting CT system within neurology applications.

The most apparent improvement in terms of diagnostic quality has been the increased spatial resolution. We mainly use that for temporal bone scans [Figure 1], but it’s also useful for angiographies. We’ve also been able to reduce contrast agent dose by about 30 percent so far, and we expect further reductions will come. Dual or multi-energy data in fast scan modes (FLASH) has also proven valuable.

Our patients benefit from the fact that we can now use fast scanning modes to reduce the risk of motion artifacts while still obtaining dual- or multi-energy data. We’ve also been able to show that the attenuation measurements are more stable with photon-counting CT than with our traditional scanners. This opens up many interesting opportunities, not least for brain volumetrics, which is an important field in neurodegeneration that has so far mainly been dependent on high-quality 3D MRI (magnetic resonance imaging). We’re planning to explore whether we can now provide similar data for dementia investigations using CT instead of MRI.

The new system benefits all patients who have a particular need for a lower ionizing radiation dose – especially children, young adults, and pregnant woman. So far, about ten percent of our scans have been pediatric patients, and it’s great to see that the dose reductions are already benefiting them. Another concrete example is when we have patients who need an angiography but can’t tolerate conventional doses of iodine contrast agents due to impaired renal function. Now we can reduce the contrast dose by at least half, making it possible to scan many of these patients. That’s particularly helpful when MRI or ultrasound aren’t an option.

The most important thing with increased amounts of data is to have automated and standardized viewing protocols in the PACS (picture archiving and communication system) so that the information is always at hand where you need it. I hope that AI will make setting up these protocols easier and that algorithms will be able to further improve our contrast-to-noise ratio and spatial resolution.