# US 7,609,814 B2 · Adaptive medical image and mask data processing system

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- Number: US 7,609,814 B2
- Document ID: US7609814B2
- Status: Granted
- Kind: B2
- Application number: 12/266,961
- Filed: 2008-11-07
- Published: 2009-07-16
- Granted: 2009-10-27
- Earliest claimed: 2008-01-15
- Assignees: Siemens Medical Solutions USA, Inc.
- Inventors: John Baumgart
- Web page: https://patentgrep.com/patent/US7609814B2

## CPC

- A61B 6/504: {for diagnosis of blood vessels, e.g. by angiography}
- A61B 6/463: {characterised by displaying multiple images or images and diagnostic data on one display}
- A61B 6/481: {involving the use of contrast agents}
- A61B 6/5235: {combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT}
- A61B 6/547: {involving tracking of position of the device or parts of the device}
- A61B 6/588: {Setting distance between source unit and detector unit}
- A61B 6/589: {Setting distance between source unit and patient}
- G06T 5/50: using two or more images, e.g. averaging or subtraction
- G06T 7/0012: {Biomedical image inspection}
- A61B 6/04: Positioning of patients; Tiltable beds or the like
- A61B 6/4441: {the rigid structure being a C-arm or U-arm}
- G06T 2207/10121: Fluoroscopy
- G06T 2207/20221: Image fusion; Image merging
- G06T 2207/30104: Vascular flow; Blood flow; Perfusion
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A system and method are disclosed for allowing the user to change the patient table position or x-ray detector position during an angiographic roadmapping procedure while still displaying a properly registered roadmap display by adapting the mask image to the new position. A system and method are further disclosed for allowing the user to change the field of view size (i.e., zoom factor) of the x-ray detector during an angiographic roadmapping procedure by matching the size of the existing mask to the live image.

## Claims

### Claim 1

A method for adjusting an angiographic roadmapping mask, comprising:
obtaining an original roadmapping mask of a targeted patient tissue region;
obtaining a live fluoroscopic image of at least a portion of the targeted patient tissue region using an x-ray source and an x-ray detector;
sensing a change comprising at least one of: a position change of a patient table, a change in a distance between the x-ray source and the x-ray detector, and a change in a field of view of the x-ray detector;
adjusting the roadmapping mask to match the live fluoroscopic image in response to the sensed change; and
combining the adjusted roadmapping mask and the live fluoroscopic image to provide a displayed superimposed image to a user.

### Claim 2 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises detecting a position change of a patient table, predicting a new field of view of the x-ray detector based on the detected position change, and panning the roadmapping mask according to predicted new field of view.

### Claim 3 (depends on 2)

The method of claim 2, wherein the panning step comprises translating the original roadmapping mask in the direction of table movement by an amount equal to the change in relative location between the table and the detector.

### Claim 4 (depends on 3)

The method of claim 3, further comprising setting any pixels that are undefined as a result of the translating step to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 5 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises detecting a change in a distance between the x-ray source and the x-ray detector, and re-scaling the original roadmapping mask to match a pixel size of the live fluoroscopic image based on the detected change.

### Claim 6 (depends on 5)

The method of claim 5, wherein when the detected change represents an increase the original roadmapping mask is enlarged and cropped to match the size of the live fluoroscopic image, and wherein when the detected change represents a decrease the original roadmapping mask is reduced and padded to match the size of the live fluoroscopic image.

### Claim 7 (depends on 6)

The method of claim 6, wherein the padded pixels are set to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 8 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises detecting a change in the field of view of the x-ray detector, and re-scaling the original roadmapping mask accordingly to match a resolution and a size of the live fluoroscopic image.

### Claim 9 (depends on 8)

The method of claim 8, wherein when the field of view is increased the roadmap mask is scaled down and padded to match the resolution and size of the live fluoroscopic image, and when the filed of view is decreased the roadmapping mask is scaled up and cropped to match the resolution and the size of the live fluoroscopic image.

### Claim 10 (depends on 9)

The method of claim 9, wherein the padded pixels are set to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 11 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises:
sensing a movement of the patient table;
applying a conversion factor to the sensed movement of the patient table to obtain a pixel movement value for the original roadmapping mask, where the conversion factor is determined using the relative geometric positioning of the x-ray source, the x-ray detector, and the patient table; and
translating the original roadmapping mask by the pixel movement value.

### Claim 12 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises:
sensing a change in distance between the x-ray source and one of the patient table and the x-ray detector;
applying a conversion factor to convert the change in distance into a discrete change in pixel size of the original roadmapping mask, where the conversion factor is determined using a triangulation between the x-ray source, the x-ray detector, and the patient table; and
resizing the original roadmapping mask by the change in pixel size.

### Claim 13 (depends on 1)

The method of claim 1, wherein the step of adjusting the roadmapping mask comprises:
determining an initial field of view of the x-ray detector and calculating a pixel size of the x-ray detector based on the initial field of view;
sensing a change in the initial field of view of the x-ray detector and converting the sensed change into a proportional change in the pixel size; and
changing the scale of the original roadmapping mask based on the proportional change in the pixel size.

### Claim 14 (depends on 1)

The method of claim 1, wherein the combining step comprises digitally subtracting the adjusted roadmapping mask from the live fluoroscopic image.

### Claim 15

A method for performing angiographic roadmapping, comprising:
obtaining an original roadmapping mask of a targeted patient tissue region using an x-ray source and an x-ray detector;
obtaining a live fluoroscopic image of at least a portion of the targeted patient tissue region;
sensing a change comprising at least one of: a position change of a patient table, a change in a distance between the x-ray source and the x-ray detector, and a change in a field of view of the x-ray detector;
adjusting the original roadmapping mask to match a portion of the live fluoroscopic image in response to the sensed change; and
combining the adjusted roadmapping mask and the live fluoroscopic image to provide a displayed superimposed image to a user.

### Claim 16 (depends on 15)

The method of claim 15, wherein the step of adjusting the original roadmapping mask comprises detecting a position change of a patient table positioned adjacent to the x-ray detector, predicting a new field of view of the x-ray detector based on the detected position change, and panning the original roadmapping mask according to the predicted new field of view.

### Claim 17 (depends on 16)

The method of claim 16, wherein the panning step comprises translating the original roadmapping mask by an amount equal to the change in relative location between the table and the detector.

### Claim 18 (depends on 17)

The method of claim 17, further comprising setting any pixels that are undefined as a result of the translating step are set to a predetermined value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 19 (depends on 15)

The method of claim 15, wherein the step of adjusting the original roadmapping mask comprises detecting a change in a distance between the x-ray source and the x-ray detector, and re-scaling the original roadmapping mask to match a pixel size of the live fluoroscopic image based on the detected change.

### Claim 20 (depends on 19)

The method of claim 19, wherein when the detected change represents an increase, the original roadmapping mask is enlarged and cropped to match the size of the live fluoroscopic image, and wherein when the detected change represents a decrease, the original roadmapping mask is reduced and padded to match the size of the live fluoroscopic image.

### Claim 21 (depends on 20)

The method of claim 20, wherein the padded pixels are set to a predetermined value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 22 (depends on 15)

The method of claim 15, wherein the step of adjusting the original roadmapping mask comprises detecting a change in a field of view of the x-ray detector and re-scaling the original roadmapping mask accordingly to match a resolution and a size of the live fluoroscopic image.

### Claim 23 (depends on 22)

The method of claim 22 wherein when the field of view is increased the roadmapping mask is scaled down and the image padded to match the resolution and size of the live fluoroscopic image, and when the field of view is decreased the roadmapping mask is scaled up and the image cropped to match the resolution and the size of the live fluoroscopic image.

### Claim 24 (depends on 23)

The method of claim 23, wherein the padded pixels are set to a predetermined value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 25 (depends on 15)

The method of claim 15, wherein the step of adjusting the roadmapping mask comprises:
sensing a movement of the patient table;
applying a conversion factor to the sensed movement of the patient table to obtain a pixel movement value for the original roadmapping mask, where the conversion factor is determined using the relative geometric positioning of the x-ray source, the x-ray detector, and the patient table; and
translating the original roadmapping mask by the pixel movement value.

### Claim 26 (depends on 15)

The method of claim 15, wherein the step of adjusting the roadmapping mask comprises:
sensing a change in distance between the x-ray source and one of the patient table and the x-ray detector;
applying a conversion factor to convert the change in distance into a discrete change in pixel size of the original roadmapping mask, where the conversion factor is determined using a triangulation between the x-ray source, the x-ray detector, and the patient table; and
resizing the original roadmapping mask by the change in pixel size.

### Claim 27 (depends on 15)

The method of claim 15, wherein the step of adjusting the roadmapping mask comprises:
determining an initial field of view of the x-ray detector and calculating a pixel size of the x-ray detector based on the initial field of view;
sensing a change in the initial field of view of the x-ray detector and converting the sensed change into a proportional change in the pixel size; and
changing the scale of the original roadmapping mask based on the proportional change in the pixel size.

### Claim 28 (depends on 15)

The method of claim 15, wherein the combining step comprises digitally subtracting the adjusted roadmapping mask from the live fluoroscopic image.

### Claim 29

A system for adjusting an angiographic roadmapping mask, comprising:
an x-ray source, an x-ray detector, a patient table, a display; and
a machine-readable storage medium encoded with a computer program code such that, when the computer program code is executed by a processor, the processor performs a method comprising:
obtaining an original roadmapping mask of a targeted patient tissue region;
obtaining a live fluoroscopic image of at least a portion of the targeted patient tissue region using the x-ray source and the x-ray detector;
sensing a change comprising at least one of: a position change of a patient table, a change in a distance between the x-ray source and the x-ray detector, and a change in a field of view of the x-ray detector;
adjusting the original roadmapping mask to match a portion of the live fluoroscopic image in response to the sensed change;
combining the adjusted roadmapping mask and the live fluoroscopic image to provide a superimposed image; and
displaying the superimposed image to a user via the display.

### Claim 30 (depends on 29)

The system of claim 29, wherein method performed by the processor further comprises detecting a position change of a patient table, predicting a new field of view of the x-ray detector based on the detected position change, and panning the roadmapping mask according to predicted new field of view.

### Claim 31 (depends on 30)

The system of claim 30, wherein panning the roadmapping mask comprises translating the original roadmapping mask in the direction of table movement by an amount equal to the change in relative location between the table and the detector.

### Claim 32 (depends on 31)

The system of claim 31, wherein the method performed by the processor further comprises setting any pixels that are undefined as a result of translating step to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 33 (depends on 29)

The system of claim 29, wherein adjusting the roadmapping mask comprises detecting a change in a distance between the x-ray source and the x-ray detector, and re-scaling the original roadmapping mask to match a pixel size of the live fluoroscopic image based on the detected change.

### Claim 34 (depends on 33)

The system of claim 33, wherein when the detected change represents an increase, the method performed by the processor further comprises enlarging and cropping the original roadmap mask to match the size of the live fluoroscopic image, and wherein when the detected change represents a decrease, the method performed by the processor further comprises reducing and padding the original roadmapping mask to match the size of the live fluoroscopic image.

### Claim 35 (depends on 34)

The system of claim 34, wherein the method performed by the processor further comprises setting the padded pixels to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 36 (depends on 29)

The system of claim 29, wherein the step of adjusting the roadmapping mask comprises detecting a change in the field of view of the x-ray detector, and re-scaling the original roadmapping mask accordingly to match a resolution and a size of the live fluoroscopic image.

### Claim 37 (depends on 36)

The system of claim 36, wherein when the field of view is increased, the method performed by the processor further comprises scaling down and padding the roadmapping mask to match the resolution and size of the live fluoroscopic image, and when the filed of view is decreased, the method performed by the processor further comprises scaling up and cropping the roadmapping mask to match the resolution and the size of the live fluoroscopic image.

### Claim 38 (depends on 35)

The system of claim 35, wherein the padded pixels are set to a neutral background value to minimize subtraction artifacts in areas of the live fluoroscopic image for which no roadmapping mask was acquired.

### Claim 39 (depends on 29)

The system of claim 29, wherein the step of adjusting the roadmapping mask comprises:
sensing a movement of the patient table;
applying a conversion factor to the sensed movement of the patient table to obtain a pixel movement value for the original roadmapping mask, where the conversion factor is determined using the relative geometric positioning of the x-ray source, the x-ray detector, and the patient table; and
translating the original roadmapping mask by the pixel movement value.

### Claim 40 (depends on 29)

The system of claim 29, wherein the step of adjusting the roadmapping mask comprises:
sensing a change in distance between the x-ray source and one of the patient table and the x-ray detector;
applying a conversion factor to convert the change in distance into a discrete change in pixel size of the original roadmapping mask, where the conversion factor is determined using a triangulation between the x-ray source, the x-ray detector, and the patient table; and
resizing the original roadmapping mask by the change in pixel size.

### Claim 41 (depends on 29)

The system of claim 29, wherein the step of adjusting the roadmapping mask comprises:
determining an initial field of view of the x-ray detector and calculating a pixel size of the x-ray detector based on the initial field of view;
sensing a change in the initial field of view of the x-ray detector and converting the sensed change into a proportional change in the pixel size; and
changing the scale of the original roadmapping mask based on the proportional change in the pixel size.

### Claim 42 (depends on 29)

The system of claim 29, wherein the combining step comprises digitally subtracting the adjusted mask from the live fluoroscopic image.