Pulmonary V/Q Mapping via CT Registration and Multi-Energy Scans
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Solution Overview
Problem
Current imaging modalities lack a practical and reliable method for providing quantitative assessments of pulmonary functional deficits alongside detailed lung structure assessments, with nuclear medicine V/Q scans being non-diagnostic due to poor resolution, and dual energy CT methods using xenon gas being expensive and difficult to control clinically.
Innovation Solution
A protocol involving a coached non-contrast breath hold scan at total lung capacity (TLC) combined with a dual energy CT perfused blood volume (PBV) scan at functional residual capacity (FRC) to quantify regional ventilation, perfusion, and V/Q ratios, using image registration to co-register ventilation with perfusion, generating detailed V/Q maps without contrast agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nuclear medicine V/Q scans are used to assess pulmonary function, then quantitative assessment of ventilation and perfusion is achieved, but image resolution is poor making the scans non-diagnostic
Solution Approach 1:
The patent combines ventilation assessment (from non-contrast CT at different lung volumes) and perfusion assessment (from DECT with contrast agent) into a single integrated imaging protocol. This merging allows both quantitative functional assessment and high-resolution anatomical imaging to be achieved simultaneously in one examination, eliminating the need for separate nuclear medicine V/Q scans.
Solution Approach 2:
The DECT system is used to perform multiple functions: it assesses perfusion through contrast agent distribution, enables ventilation assessment through virtual non-contrast imaging and image registration, and provides high-resolution anatomical detail. This multi-functionality replaces the need for separate specialized imaging modalities.
2Measurement precision
If dual energy CT with xenon gas is used to assess ventilation, then quantitative ventilation measurement is achieved, but the method is expensive and difficult to control clinically
Solution Approach 1:
The patent replaces expensive xenon gas with ordinary air as the ventilation challenge agent. Patients simply hold their breath at different volumes, eliminating the need for costly specialized gases while maintaining the ability to assess ventilation through image registration of lung volume changes.
Solution Approach 2:
The system uses the patient's own breath-holding capability at different lung volumes to generate the ventilation data. The patient cooperates by holding breath at instructed volumes, and the system automatically processes the images through registration algorithms, making the procedure simple and clinically controllable.
3Measurement precision
If iodine contrast media is used with DECT to assess perfusion, then perfused blood volume is accurately measured, but radiation dose increases
Solution Approach 1:
The patent uses a single-phase contrast enhancement protocol rather than dynamic multi-phase imaging. By acquiring images at one specific time point during contrast circulation (functional residual capacity phase), the method achieves sufficient perfusion measurement accuracy while minimizing radiation exposure compared to repeated imaging sequences.
Solution Approach 2:
The single DECT examination at functional residual capacity serves multiple purposes: it assesses perfusion through contrast distribution, enables ventilation assessment through virtual non-contrast imaging, and provides anatomical detail. This consolidation reduces the total number of scans and cumulative radiation dose compared to multiple separate imaging protocols.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides improved resolution and contrast, faster imaging with lower radiation doses, enabling better functional and anatomical information for lung analysis, suitable for pre/post-surgery evaluations and disease diagnosis, with applications in identifying pulmonary embolism, lung surgery planning, and assessing diseases like COPD and pulmonary hypertension.
Implementation Method 1
dual energy computed tomography (DECT) assessment of regional pulmonary perfused blood volume via use of an iodinated contrast agent has been shown to provide an index of regional perfusion
Implementation Method 2
a material decomposition method is used to quantify regional iodine (6, 7, 22), and to generate a virtual non-contrast image (4) of the lung at FRC
Implementation Method 3
Using image registration methods, the TLC lung image is warped to the FRC virtual non-contrast image, generating an image of ventilation (regional Jacobians) which is precisely mapped to the perfused blood volume image
Data Source
AI summary
A method for imaging a lung of a patient is provided. The method includes acquiring a full inspiration computed tomography (CT) scan of the lung to provide a total lung capacity (TLC) image and acquiring a functional residual capacity contrast enhanced multi-energy CT scan of the lung. The method further includes processing the functional residual capacity contrast enhanced multi-energy CT scan of the lung to generate a perfused blood volume (PBV) image and a virtual non-contrast (VNC) image. The method further includes registering the TLC image to at least one of the PBV and VNC images so as to provide a map of regional ventilation and to co-register local ventilation with blood perfusion, generating a lung performance metric using the co-registered images, and outputting the lung performance metric at a user interface of a computing device.