Table 2. Summary of the imaging techniques discussed in this article, their characteristics, and the minimum age of the patients in the referenced studies.
| Imaging technique | Principle | Usefulness | Limitations | Clinical applicability | Patients’ age (youngest) |
|---|---|---|---|---|---|
| DWI | Measures diffusion of water molecules | Can help differentiate aggressive tumours (increased diffusion restriction) from low-grade and MCD | Susceptible to motion artefacts, low spatial resolution | Primarily used for detecting acute stroke | Not reported |
| DTI | Measures directional diffusion of water molecules | Detailed visualisation of white matter tracts, additional information on the microstructures of the brain | Possible incorrect representation of neural paths in regions with dense fibre populations; cannot distinguish afferent from efferent projections | Evaluation of the white matter networks before and after surgery | Less than 1 year old |
| DKI | Measures non-uniform (non-Gaussian) diffusion of water molecules in complex tissue | More accurate model of diffusion and improved white matter characterization | Relatively long-time acquisition, reproducibility | Detecting subtle microstructural abnormalities, such as in mesial temporal sclerosis | 5 years old |
| NODDI | Measures the orientation and density of neurites | Contribution of tissue components individually (intraneurite water, extraneurite water and cerebrospinal fluid) | Requires advanced processing techniques, longer acquisition times | Better understanding of neural architecture in epilepsy | 6 years old |
| DIR | Uses dual inversion pulses to null signals from CSF and white matter | Improved grey matter lesion detection, enhances visibility of cortical structures | Prolonged imaging times, sequence-specific artefacts | Visualising cortical lesions and grey matter abnormalities | 2 years old |
| MP2RAGE | Combines two gradient echoes to obtain a T1-weighted imaging with reduced bias | Higher resolution | More suited for 3 T or higher field scanners | Useful in detecting subtle brain lesions and anatomical details | 7 years old |
| EDGE | Adaptation of MPRAGE/MP2RAGE | Higher contrast ratio for the subcortical regions | Susceptible to artefacts, requires precise parameter settings | Enhancing visibility of lesion margins and anatomical structures in epilepsy | 14 years old |
| FLAWS | Similar to DIR, uses two inversion times of MP2RAGE to suppress CSF and white matter | Better grey matter visualisation at high magnetic field |
Long acquisition time | Improving contrast in cortical regions for cortical/subcortical lesions | 8 years old |
| ASL | Uses magnetically labelled arterial blood as an endogenous tracer | Non-invasive measurement of cerebral blood flow, no radiation exposures | Sensitive to delayed blood flow, age-related CBF changes | Assessing cerebral perfusion and identifying perfusion abnormalities | Less than 1 year old |
| QSM | Measures magnetic susceptibility to quantify tissue properties | Quantifies concentrations of iron, calcium, and other substances; improves detection of microbleeds and calcifications | Susceptible to artefacts from air-tissue interfaces, requires complex post-processing | Identification of epileptogenic tubers in TSC; offers a valuable tool for the detailed assessment of mineral deposits and tissue composition | 2 years old |
| MRS | Measures the concentration of metabolites in tissues | Provides metabolic information, can detect abnormalities in neuronal health, energy metabolism, and membrane turnover | Lower spatial resolution compared to structural MRI, susceptible to motion artefacts, complex data interpretation | Detecting and characterising metabolic changes in epilepsy, characterising tumours | Less than 1 year old |
| MRF | Generate quantitative tissue properties | High reproducibility, more objective evaluation of different tissues | Requires advanced softwares, long acquisition time | Quantitative assessment and comparison of tissue properties | 6 years old |
| MTI | Measures the exchange of magnetization between free water and macromolecular-bound water | Enhances contrast between normal and pathological tissues, useful in detecting demyelination | Sensitive to radiofrequency field inhomogeneities, longer scan times | Primarily utilised in multiple sclerosis, it has also shown good sensitivity in identifying MCD | Less than 1 year old |
| VBM, including MAP |
Statistical analysis of differences in brain anatomy using voxel-wise comparison | Identifies brain volume changes | Requires large sample sizes for statistical power, sensitive to preprocessing steps | Detecting and quantifying grey matter atrophy, useful in epilepsy research and diagnosis | 6 years old |
| SBM | Analyses cortical thickness, surface area, and volume | Detailed analysis of cortical morphology, sensitive to subtle changes in cortical structure | Requires high-quality images, sensitive to preprocessing steps | Primarily used in studying disorders like autism and schizophrenia, its application in epilepsy research is relatively limited | 1 year old |
| fMRI | Measures brain activity by detecting changes in blood flow (BOLD) | Maps brain function, identifies active brain regions during tasks | Susceptible to motion artifacts and patient compliance | Assessing brain functions, identifying seizure focus, presurgical mapping in epilepsy patients | 6 years old |
| AI | Uses machine learning algorithms to analyse imaging data | Enhance diagnostic accuracy, improve efficiency, reduce workload | Dependence on large datasets, need rigorous validation | Automated detection of abnormalities, surgical outcome prediction, improving diagnostic accuracy in epilepsy | 3 years old |
DWI, diffusion-weighted imaging; DTI, diffusion tensor imaging; DKI, diffusion kurtosis imaging; NODDI, neurite orientation dispersion and density imaging; DIR, double inversion recovery; MP2RAGE, magnetization prepared 2 rapid gradient echo; EDGE, edge-enhancing gradient echo; FLAWS, fluid and white matter suppression; ASL, arterial spin labeling; QSM, quantitative susceptibility mapping; MRS, magnetic resonance spectroscopy; MRF, magnetic resonance fingerprinting; MTI, magnetization transfer imaging; VBM, voxel-based morphometry; MAP, morphometric analysis program; SBM, surface-based morphometry; fMRI, functional magnetic resonance imaging; AI, artificial intelligence; CSF, cerebrospinal fluid; BOLD, blood oxygenation-level dependent; MCD, malformations of cortical development; CBF, cerebral blood flow.