Dr. Francesco Pisana Profile

Dr. Francesco Pisana

at Siemens Healthineers

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Author

Publications (3)

Proceedings Article | 1 March 2019 Paper

Image-based noise reduction for material decomposition in dual or multi energy computed tomography

Mahmut Özdemir, Sabrina Dorn, Francesco Pisana, Monika Uhrig, Heinz-Peter Schlemmer, Marc Kachelrieß

Proceedings Volume 10948, 109482U (2019) https://doi.org/10.1117/12.2513388

KEYWORDS: Denoising, Image filtering, Computed tomography, X-ray computed tomography

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Proceedings Article | 9 March 2017 Presentation + Paper

High quality high spatial resolution functional classification in low dose dynamic CT perfusion using singular value decomposition (SVD) and k-means clustering

Francesco Pisana, Thomas Henzler, Stefan Schönberg, Ernst Klotz, Bernhard Schmidt, Marc Kachelrieß

Proceedings Volume 10132, 101320M (2017) https://doi.org/10.1117/12.2251161

KEYWORDS: Functional imaging, Computed tomography, Spatial resolution, Visualization, Liver, Brain, Signal attenuation, Brain mapping, Blood, Blood circulation

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Dynamic CT perfusion acquisitions are intrinsically high-dose examinations, due to repeated scanning. To keep radiation dose under control, relatively noisy images are acquired. Noise is then further enhanced during the extraction of functional parameters from the post-processing of the time attenuation curves of the voxels (TACs) and normally some smoothing filter needs to be employed to better visualize any perfusion abnormality, but sacrificing spatial resolution. In this study we propose a new method to detect perfusion abnormalities keeping both high spatial resolution and high CNR. To do this we first perform the singular value decomposition (SVD) of the original noisy spatial temporal data matrix to extract basis functions of the TACs. Then we iteratively cluster the voxels based on a smoothed version of the three most significant singular vectors. Finally, we create high spatial resolution 3D volumes where to each voxel is assigned a distance from the centroid of each cluster, showing how functionally similar each voxel is compared to the others. The method was tested on three noisy clinical datasets: one brain perfusion case with an occlusion in the left internal carotid, one healthy brain perfusion case, and one liver case with an enhancing lesion. Our method successfully detected all perfusion abnormalities with higher spatial precision when compared to the functional maps obtained with a commercially available software. We conclude this method might be employed to have a rapid qualitative indication of functional abnormalities in low dose dynamic CT perfusion datasets. The method seems to be very robust with respect to both spatial and temporal noise and does not require any special a priori assumption. While being more robust respect to noise and with higher spatial resolution and CNR when compared to the functional maps, our method is not quantitative and a potential usage in clinical routine could be as a second reader to assist in the maps evaluation, or to guide a dataset smoothing before the modeling part.

Proceedings Article | 22 March 2016 Paper

Low dose CT perfusion using k-means clustering

Francesco Pisana, Thomas Henzler, Stefan Schönberg, Ernst Klotz, Bernhard Schmidt, Marc Kachelrieß

Proceedings Volume 9783, 97833M (2016) https://doi.org/10.1117/12.2214709

KEYWORDS: Computed tomography, Spatial resolution, Brain, Tissues, Image quality, Tumors, Denoising, Blood, Targeting Task Performance metric, Brain mapping

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