Method and system for abnormal tissue detection using z-scores in a joint histogram

An imaging system configured for automatically comparing organ tissue properties of a patient with corresponding organ tissue properties of a group of healthy subjects, the imaging system comprising:

• a processor and an accessible memory, the imaging system being configured to:
• determine a population norm for said organ tissue properties by:
• a) selecting at least two different tissue properties of the organ to be investigated;
• b) determining for each tissue property previously selected and for each subject of said group a quantitative tissue property map;
• c) for each subject of the group, calculating a joint histogram from all the quantitative tissue property maps obtained for said subject;
• d) normalizing each previously calculated joint histogram;
• and
• e) determining an averaged joint histogram by averaging the normalized joint histograms across all subjects of the healthy group, wherein said averaged joint histogram defines said population norm;
• automatically perform a comparison of the averaged joint histogram with a patient joint histogram obtained for the organ tissue properties of the patient, wherein, for determining the patient joint histogram, the imaging system is configured for:
• b1) determining for each tissue property selected in step a) a quantitative tissue property map for the patient organ;
• and
• c1) calculating a joint histogram from all the quantitative tissue property maps obtained for the organ of said patient;
• d1) normalizing the previously calculated joint histogram;
• and
• and wherein the comparison is obtained by calculating a statistical deviation of values of the patient joint histogram with respect to values of the averaged joint histogram and mapping said statistical deviation to the patient organ.