Determining an initialization time point of imaging using a contrast medium

Patent metadata

Field	Value
Publication number	US-2016296178-A1
Application number	US-201615079477-A
Country	US
Kind code	A1
Filing date	Mar 24, 2016
Priority date	Apr 7, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

A method is described for determination of an initialization time point of imaging of a region of interest of an object to be examined. A slice of the object is selected for bolus-tracking images in which the flow of a fluid flowing toward the region of interest is observable. A plurality of bolus-tracking images of the slice is taken. Time-density curves are determined based upon intensity values assigned to the individual image points acquired in the plurality of bolus-tracking images for the selected slice. Individual image points are divided into groups according to similarity of time-density curves assigned to the individual image points. Finally, the time at which an intensity value assigned to one of the groups exceeds a threshold value is determined. Also described are a method for carrying out the imaging of a region of interest; an initialization time point determination device; and a computed tomography system.

First claim

What is claimed is:

1 . A method for determining an initialization time point of imaging of a region of interest of an object to be examined, the method comprising:
selecting a slice of the object to be examined for subsequent bolus-tracking images, in which a fluid flowing to the region of interest is observable; taking a plurality of bolus-tracking images of the selected slice; determining respective time-density curves on the basis of the intensity values assigned to respective individual image points acquired during the plurality of bolus-tracking images of the selected slice; dividing the individual image points into groups according to the similarity of the time-density curves assigned to the individual image points; and determining a time, at which an intensity value assigned to one of the groups reaches a threshold value, as the initialization time point of imaging.

2 . The method of claim 1 , wherein at least one of:
the object to be examined has been given a contrast medium before the first bolus-tracking image, and at least one of the groups, for which the assigned time-density curves is most similar to a reference artery signal curve, is identified as a group with an arterial signal.

3 . The method of claim 1 , wherein the imaging includes CT imaging and the intensity values include attenuation values.

4 . The method of claim 1 , wherein the imaging includes MRI imaging.

5 . The method of claim 1 , wherein the dividing of the individual image points into groups is performed with the aid of a clustering method.

6 . The method of claim 1 , wherein the group of image points, in which the intensity values are the first to exceed a threshold value, is identified as a group with an arterial signal.

7 . The method of claim 1 , wherein groups with time-density curves, correlated with the heart rate or respiration of the object to be examined, are identified as separate groups.

8 . The method of claim 1 , wherein at least one of:
the number of groups is defined in advance as a function of the maximum time that should be required by the determination method, the bolus-tracking images will be taken in a restricted partial region of interest of the selected plane, which is defined as the region in which an arterial signal is to be expected, group centers are defined in advance from models for the groups in that a predetermined time-density curve is assigned to each of the groups as a group center, and randomly chosen group centers are selected as initial group centers, adapted during the application of the cluster method to the time-density curves assigned to the image points grouped therearound.

9 . The method of claim 1 , wherein, during the dividing of the individual image points into groups, only image points with assigned intensity values in a value interval are taken into account.

10 . The method of claim 9 , wherein at least one of:
the value interval include a range from −50 HU to 150 HU, and the images recorded in the bolus-tracking images are registered in sequence.

11 . The method of claim 5 , wherein a hierarchical cluster method or a K-means cluster method is used as the cluster method.

12 . A method for imaging of a region of interest, comprising:
performing the method of claim 1 ; and starting the imaging at the initialization time point determined according to the method of claim 1 .

13 . An initialization time point determination device for determining an initialization time point of imaging of a region to be depicted of an object to be examined, comprising:
an input interface to receive selection guidelines with respect to the selection of a slice of the object to be examined for subsequent bolus-tracking images, in which a fluid flowing to the region of interest is observable; an actuation unit to actuate an imaging unit for taking a plurality of bolus-tracking images of the selected slice; a raw data acquisition unit to acquire raw data with the plurality of bolus-tracking images; a reconstruction unit to reconstruct image data including respective intensity values assigned to respective individual image points on the basis of the acquired raw data; an analysis unit to divide the individual image points into groups according to a similarity of time-density curves assigned to the individual image points, determined on the basis of the respective assigned intensity values assigned to the respective individual image points; and an initialization time point determination unit to determine a time at which an intensity value assigned to one of the groups reaches a threshold value.

14 . An imaging medical device, comprising:
a control device including the initialization time point determination device of claim 13 .

15 . A non-transitory computer readable medium a computer program, directly loadable into a storage device of a control device of an imaging medicinal device, including program segments to execute the method of claim 1 when the computer program is executed in the control device of the imaging medicinal device.

16 . A non-transitory computer-readable medium, on which computing unit-readable and -executable program segments are stored, to execute the method of claim 1 when the program segments are executed by the computing unit.

17 . The method of claim 5 , wherein, during the dividing of the individual image points into groups, only image points with assigned intensity values in a value interval are taken into account.

18 . The method of claim 17 , wherein at least one of:
the value interval include a range from −50 HU to 150 HU, and the images recorded in the bolus-tracking images are registered in sequence.

19 . A method for imaging of a region of interest, comprising:
performing the method of claim 3 ; and starting the imaging at the initialization time point determined according to the method of claim 3 .

20 . A method for imaging of a region of interest, comprising:
performing the method of claim 4 ; and starting the imaging at the initialization time point determined according to the method of claim 4 .

21 . The imaging medical device of claim 14 , wherein the imaging device is a computed tomography system.

Assignees

• Siemens Ag

Inventors

• Korporaal Johannes Georg

Classifications

• G06T2207/30104

  Vascular flow; Blood flow; Perfusion · CPC title

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• A61B6/03 Primary

  Computed tomography [CT] · CPC title

• A61B6/5288

  involving retrospective matching to a physiological signal · CPC title

• G06T2207/10081

  Computed x-ray tomography [CT] · CPC title