Image reconstruction based on energy-resolved image data from a photon-counting multi-bin detector

A system for image reconstruction based on energy-resolved image data from a photon-counting multi-bin detector or an intermediate storage,

• wherein the system is configured to process the energy-resolved image data by performing at least two separate basis decompositions using different number of basis functions for modeling linear attenuation,
• wherein the system is configured to perform a first basis decomposition using a first smaller set of basis functions to obtain at least one first basis image representation,
• wherein the system is configured to perform a second basis decomposition using a second larger set of basis functions to obtain at least one second basis image representation;
• and
• wherein the system is configured to reconstruct a first image based on said at least one first basis image representation obtained from the first basis decomposition;
• wherein the system is configured to combine the first image with information representative of said at least one second basis image representation,
• wherein the system is configured to perform two separate basis decompositions on projection image data, resulting in respective line integral estimates of basis function coefficients, where the first decomposition has a smaller set of basis functions in the assumed functional form of the unknown linear attenuation map, and the second decomposition has a larger set of basis functions including a basis function for representing a specific compound or element,
• wherein the system is configured to perform a first image reconstruction using the line integral estimates from the first decomposition using the smaller number of basis functions, resulting in a display image with relatively low noise level,
• wherein the system is configured to perform a second image reconstruction using the line integral estimates for the basis coefficient(s) corresponding to said compound or element from the second decomposition using the larger number of basis functions, resulting in a physically interpretable map of the concentration or density of said compound or element, and
• wherein the system is configured to combine the display image with relatively low noise level with the physically interpretable map of the concentration or density of said compound or element.