Dual-Modality Contrast Agent for Tumor Imaging Stability
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Solution Overview
Problem
Current medical imaging technologies, such as MRI and optical imaging, face limitations in sensitivity and resolution, making it challenging to detect and differentiate tumor lesions effectively, especially due to the rapid excretion and instability of traditional contrast agents like gadopentetate dimeglumine and indocyanine green.
Innovation Solution
A fluorescence-magnetic resonance dual-modality contrast agent with a specific molecular structure, capable of enhancing both MRI and fluorescence imaging, featuring a high relaxation rate, excellent thermal stability, and low toxicity, which is designed to provide stable and effective imaging of living tissues and tumors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional MRI contrast agent gadopentetate dimeglumine is used, then MRI imaging can be performed, but the relaxation rate is low and the agent is quickly cleared from the body
Solution Approach 1:
The patent combines the fluorescent contrast agent indocyanine green (ICG) with the MRI contrast agent gadopentetate dimeglumine to create a dual-functional contrast agent. This merging allows the single agent to provide both fluorescence imaging and MRI capabilities, with the ICG moiety extending circulation time through protein binding while the Gd-DTPA component maintains MRI contrast function
Solution Approach 2:
The contrast agent uses a composite molecular structure where ICG is chemically conjugated to Gd-DTPA. This composite material integrates the properties of both components: the hydrophobic ICG portion binds to plasma proteins for extended circulation, while the hydrophilic Gd-DTPA portion provides efficient MRI contrast through gadolinium's paramagnetic properties
2Measurement precision
If optical imaging technology is used, then sensitivity and visualization capability are improved, but tissue penetration depth is limited and spatial resolution is low
Solution Approach 1:
The dual-modality contrast agent provides universal applicability for both optical imaging and MRI, allowing the same agent to function across different imaging modalities. This multi-functionality enables researchers to leverage the high sensitivity of fluorescence imaging for detection while using MRI for deeper tissue penetration and spatial localization
3Measurement precision
If exogenous fluorescent contrast agents are used to enhance tumor tissue contrast, then fluorescence imaging contrast is improved, but it becomes difficult to distinguish diagnostic signals from background fluorescence of normal tissues
Solution Approach 1:
The patent utilizes the specific fluorescence emission characteristics of ICG, which emits in the near-infrared region (peaking around 830 nm). This wavelength range provides superior tissue penetration and reduced background autofluorescence compared to visible light wavelengths, effectively changing the 'color' or spectral region of imaging to avoid background interference
4Illumination intensity
If ICG is used as fluorescent contrast agent, then fluorescence imaging capability is achieved, but the aqueous solution stability is poor and rapid excretion occurs
Solution Approach 1:
The Gd-DTPA moiety acts as an intermediary that modifies the pharmacokinetic behavior of ICG. When ICG is conjugated to Gd-DTPA, the resulting complex has altered stability and circulation characteristics compared to free ICG, with the DTPA chelate providing structural stability and modified clearance patterns
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
The dual-modality contrast agent significantly improves the resolution of organ boundaries and tumor detection, maintaining high signal correspondence and stability, enhancing clinical diagnostic accuracy and surgical navigation.
Implementation Method 1
MRI technology usually utilizes the differences in the 'spin-lattice relaxation time' and 'spin-spin relaxation time' of protons in different tissues or organs for imaging
Implementation Method 2
Optical imaging techniques utilize different physical parameters of light to interact with tissues for imaging, and many different optical imaging methods have been reported. These techniques rely on fluorescence, absorbed light, reflected light or bioluminescence as a source of contrast
Data Source
AI summary
A fluorescence-magnetic resonance dual-modality contrast agent, a preparation method thereof and the use thereof. The contrast agent has the following structure: X-L-Y, wherein: formula (I); R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, and R12 are each independently selected from H, halogen, OH, NH2, COOH, CONH2, NO2, CN, and low alkyl groups, the low alkyl groups can be substituted with halogen, OH, NH2, COOH, CONH2, SO3H, NO2, and CN, wherein R3 and R4, taken together with the carbon atoms to which they are attached, may form a phenyl group or a heterocyclic group; R7 and R8, taken together with the carbon atoms to which they are attached, may form a phenyl group or heterocyclic group; L is a linking group; and Y is a metal chelate.