System and Method for Simultaneously Registering Multiple Lung CT Scans for Quantitative Lung Analysis

Patent metadata

Field	Value
Publication number	US-2024371013-A1
Application number	US-202218565826-A
Country	US
Kind code	A1
Filing date	Jun 1, 2022
Priority date	Jun 1, 2021
Publication date	Nov 7, 2024
Grant date	—

Abstract

A method for simultaneously registering a plurality of computed tomography (CT) scans of a region of interest of a subject including a subject's lungs for quantitative lung analysis includes receiving a plurality of CT scans of the region of interest acquired with a CT imaging system, receiving a breathing surrogate data for the subject, the breathing surrogate data comprising an amplitude for each of the plurality of CT scans and determining a deformation based on the plurality of CT scans and the breathing surrogate data using an iterative optimization process of an objective function. The objective function can include a first term based on an approximation of local changes in Hounsfield Units (HU) adjusted for breathing of the subject and a second term based on error in the conservation of mass. At least one quantitative lung parameter may be determined based on the deformation.

First claim

1 . A method for simultaneously registering a plurality of computed tomography (CT) scans of a region of interest of a subject including a subject's lungs for quantitative lung analysis, the method comprising:
receiving a plurality of CT scans of the region of interest acquired with a CT imaging system; receiving a breathing surrogate data for the subject, the breathing surrogate data comprising an amplitude for each of the plurality of CT scans; and determining a deformation based on the plurality of CT scans and the breathing surrogate data using an iterative optimization process of an objective function having a first term based on an approximation of local changes in Hounsfield Units (HU) adjusted for breathing of the subject and a second term based on error in the conservation of mass.

2 . The method according to claim 1 , wherein the deformation is a deformation vector field (DVF).

3 . The method according to claim 1 , wherein the objective function is given by:



HU
i
′

-

HU
j
′



p

+

α
⁢



ΔΓ
ij



p

where HU are Hounsfield units of the CT scans within a lung boundary, α is a parameter used to adjust the relative importance of the first term and the second term, ΔΓ ij is a mathematical description of the conservation of mass, i and j refer to scans such that i≠j, and p is the p norm.

4 . The method according to claim 3 , wherein the first term is given by:

(

HU
i
′

-

HU
j
′

)

=

(

HU
i

-

HU
j

)

+

dHU
dA

⁢

(

A
j

-

A
i

)

where HU, is an HU value of scan i, HU j is an HU value of scan j, dHU/dA is a slope of a fit of all HUs to their respective amplitudes, A i is a surrogate amplitude of scan i, A j is a surrogate amplitude of scan j, and one of i and j is a reference scan.

5 . The method according to claim 3 , wherein the second term is given by one of:

ΔΓ
ij

=

J
ij

-

ρ
i

/

ρ
j

2

or the inverse relationship

ΔΓ
ij
′

=

1
/

J
ij

-

ρ
j

/

ρ
i

2

where J is the Jacobian of a deformation vector field (DVF), ρ i is a tissue density determined by scan i, and ρ j is a tissue density determined by scan j.

6 . The method according to claim 1 , further comprising determining at least one quantitative lung parameter based on the deformation.

7 . The method according to claim 6 , wherein the at least one quantitative lung parameter is ventilation.

8 . The method according to claim 7 , wherein the ventilation is determined as a parameterization of a Jacobian of a deformation vector field (DVF) as a function of the breathing amplitude.

9 . The method according to claim 7 , wherein the ventilation (V) is determined as a rate of change of the Jacobian (J) of the deformation vector field (DVF) with respect to breathing amplitude (A) as given by:

V
=

dJ
dA

.

10 . The method according to claim 1 , wherein each CT scan in the plurality of CT scans is acquired during free-breathing.

11 . The method according to claim 1 , wherein each CT scan in the plurality of CT scans is acquired during modified breathing.

12 . The method according to claim 1 , wherein the amplitude is calibrated based on a position of a diaphragm dome of the subject in at least one of the plurality of CT scans.

13 . The method according to claim 1 , wherein determining a deformation based on the plurality of CT scans and the breathing surrogate data using an iterative optimization process of the objective function comprises determining a deformation vector field that minimizes the objective function.

14 . A system for simultaneously registering a plurality of computed tomography (CT) scans of a region of interest of a subject including a subject's lungs for quantitative lung analysis, the system comprising:
a processor device; and a non-transitory computer-readable memory storing instructions executable by the processor device, wherein the instructions, when executed by the processor device, cause the system to:
receive a plurality of CT scans of the regio

Assignees

• Univ California

Inventors

• Low Daniel A
• Ruan Dan
• Santhanam Anand

Classifications

• G06T2207/30061

  Lung · CPC title

• G06T2207/10081

  Computed x-ray tomography [CT] · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title

• A61B6/50

  specially adapted for specific body parts; specially adapted for specific clinical applications · CPC title

• A61B6/032 Primary

  Transmission computed tomography [CT] · CPC title