Advances in application of novel magnetic resonance imaging technologies in liver disease diagnosis

Table 1 Advanced magnetic resonance imaging techniques for liver diagnosis: Comparison of clinical applications, advantages, limitations, and developments

Technique(s)	Applications	Advantages	Limitations	Developments
DWI and IVIM	Assessment of liver tumors, diffuse liver lesions, and liver function. Assessment of liver or tumor blood perfusion	Evaluate liver or tumor blood perfusion without the use of contrast agents	Poor reproducibility of IVIM and DWI	2D b-M1 acquisition improves reproducibility. The new parameter PDR improves DWI performance
MRE	Diagnosis and staging of liver fibrosis and cirrhosis. Prediction of the recurrence of HCC	Diagnosis of liver fibrosis is not affected by obesity, ascites, inflammation, and etiology	The diagnostic threshold for fibrosis is variable and conflicting	The two-step strategy can screen for liver fibrosis. LS and TS can predict HCC recurrence
CEST	Assessment of tumor metabolism and microenvironment. Monitoring of tumor treatment response	An FDG substitute that does not involve ionizing radiation	Easily affected by other factors. Long scan time	The new reagent 3OMG has unique advantages. Realization of image-guided drug delivery and integration of tumor diagnosis and treatment
CE-MRI	Diagnosis and staging of liver tumors. Detection of liver metastases and diffuse liver lesions	Provides more information about lesions compared to plain MRI. Specific probes enable visualization at the molecular level	Gd chelates can cause allergic reactions and nephrotoxicity	Multi-target probes have the potential to overcome tumor heterogeneity. Potential applications of Mn-based contrast agents in targeted tumor therapy
MRS	Diagnosis and grading of fatty liver and liver fibrosis. Metabolic evaluation of liver and intrahepatic tumors	Provides quantitative data on liver metabolism non-invasively without the use of contrast agents	Low sensitivity of 13C. Accuracy is affected by liver tissue heterogeneity and motion	Cho peak can provide more information. 31P-MRS can differentiate liver cirrhosis etiology and evaluate IRI
HP MR	Providing metabolic, perfusion, and enzymatic information on HCC	DNP improves MR signal by 10000 times. [1-13C] pyruvate has particular value in evaluating tumor metabolism	Current measurement methods still produce inevitable quantitative deviations	HyperPET is expected to elucidate complete glucose metabolism. More hyperpolarized probes are being used. Double-probe HP MR can simultaneously obtain metabolic and perfusion information
MRI radiomics	Diagnosis and prediction of immunohistochemistry features, MVI, liver fibrosis, and hepatitis.	Comprehensive, non-invasive, and quantitative observation of the spatiotemporal heterogeneity of tumors	Poor reproducibility of MRI features. MVI features are variable and conflicting in different studies	Good application value in the differential diagnosis, immunohistochemical feature prediction, and MVI prediction of HCC

CEST: Chemical exchange saturation transfer; CE-MRI: Contrast-enhanced magnetic resonance imaging; Cho: Choline; DNP: Dynamic nuclear polarization; DWI: Diffusion weighted imaging; HCC: Hepatocellular carcinoma; HP: Hyperpolarized; IRI: Ischemia-reperfusion injury; IVIM: Intravoxel incoherent motion; LS: Liver stiffness; MRE: Magnetic resonance elastography; MRI: Magnetic resonance imaging; MRS: Magnetic resonance spectroscopy; MVI: Microvascular invasion; PDR: Perfusion-diffusion ratio; TS: Tumor stiffness; PET: Positron emission tomography; FDG: Fluorodeoxyglucose; 2D: Two-dimensional.

Table 2 Comparison of performance indicators of new magnetic resonance techniques in diagnosis of liver disease

Technique	Disease	Subjects	Sensitivity (%)	Specificity (%)	NPV (%)	PPV (%)	Ref.
DWI	HCC	34	54.8	90.9	34.5	95.8	[103]
DWI	LF	40	85	82	85	83	[104]
PDR	MT	83	81	77	NA	NA	[18]
MRE	LF	59	69.0	88.2	53.6	93.5	[105]
MRS	Liver steatosis	4715	72.7-88.5	92.0-95.7	NA	NA	[106]
Gd-EOB-DTPA MRI	HCC	77	88.2	96.7	90.6	95.7	[107]
SPIO MRI	HCC	30	66.0	98.0	91.4	90.0	[108]
MRI-PDFF	NAFLD	60	96	100	92.6	89.5	[70]
Radiomics	MVI	50	90	75	NA	NA	[99]
Radiomics	MVI	981	79	81	NA	NA	[100]

DWI: Diffusion weighted imaging; HCC: Hepatocellular carcinoma; LF: Liver fibrosis; MRE: Magnetic resonance elastography; MRI: Magnetic resonance imaging; MRI-PDFF: Magnetic resonance imaging proton density fat fraction; MRS: Magnetic resonance spectroscopy; MT: Malignant tumor; MVI: Microvascular invasion; NA: Not available; NAFLD: Non-alcoholic fatty liver disease; NPV: Negative predictive value; PDR: Perfusion-diffusion ratio; PPV: Positive predictive value; SPIO: Superparamagnetic iron oxide.