1 Molecular imaging

Molecular imaging is a type of imaging that visualizes the molecular and cellular events that underlie disease mechanisms. It can use various modalities, such as positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and optical imaging. Molecular imaging can reveal the expression and activity of specific biomarkers, such as receptors, enzymes, genes, and proteins, that are associated with disease progression and response to therapy. For example, molecular imaging can detect the accumulation of amyloid-beta plaques in the brain of Alzheimer's patients, the expression of HER2 receptors in breast cancer, and the metabolism of glucose in tumors.

2 Functional imaging

Functional imaging is a type of imaging that measures the physiological and metabolic functions of tissues and organs. It can use various modalities, such as functional MRI (fMRI), diffusion tensor imaging (DTI), arterial spin labeling (ASL), and magnetic resonance spectroscopy (MRS). Functional imaging can reveal the changes in blood flow, oxygen consumption, water diffusion, and metabolite concentrations that reflect the functional status and integrity of tissues and organs. For example, functional imaging can assess the brain activity and connectivity in cognitive and emotional tasks, the integrity and connectivity of white matter fibers in neurological disorders, and the perfusion and oxygenation of tumors and ischemic regions.

3 Quantitative imaging

Quantitative imaging is a type of imaging that extracts numerical values from images that represent physical or biological properties of tissues and organs. It can use various modalities, such as computed tomography (CT), MRI, ultrasound, and X-ray. Quantitative imaging can provide objective and standardized measurements of biomarkers, such as density, volume, shape, texture, and stiffness, that are related to disease characteristics and outcomes. For example, quantitative imaging can measure the bone mineral density in osteoporosis, the tumor volume and shape in cancer staging, the liver stiffness in fibrosis, and the lung texture in emphysema.

4 Multimodal imaging

Multimodal imaging is a type of imaging that combines two or more imaging modalities to obtain complementary information about tissues and organs. It can use various combinations, such as PET/CT, PET/MRI, SPECT/CT, and MRI/ultrasound. Multimodal imaging can enhance the sensitivity and specificity of biomarkers, as well as provide spatial and temporal correlations between different types of data. For example, multimodal imaging can integrate the anatomical, functional, and molecular information from PET/CT to improve the diagnosis and staging of cancer, the assessment of treatment response, and the detection of recurrence.

5 Artificial intelligence

Artificial intelligence (AI) is a type of technology that uses algorithms and machine learning to analyze and interpret large and complex datasets from imaging modalities. It can use various methods, such as deep learning, convolutional neural networks, and natural language processing. AI can discover and validate new biomarkers, as well as improve the accuracy and efficiency of existing biomarkers, by extracting features, patterns, and insights from images that are beyond human perception and cognition. For example, AI can identify and classify subtle lesions and abnormalities in images, predict the prognosis and survival of patients, and generate synthetic images and reports.