Table 3.

Characteristics of the included studies

Author (Year)	Origin country	Study type	Total patients#		Age (in years) Mean±SD (range)	Modalities used	Research object	Tumor staging	MRI machine	MRI sequence	Time between MRI recording and tumor resection
			M	F
Alsaffar et al. (2016)[99]	Canada	Prospective	53		64	Clinical, MRI, histopathological	DOI	T1–T4	NP	NP	NP
			34	19
Jayasankaran et al. (2017)[96]	India	Prospective	59		51.81 (18–74)	Clinical, MRI, histopathological	DOI Infiltration of sublingual space Infiltration of extrinsic muscles Involvement of mylohyoid muscle	T1–T4	3.0 Tesla	T1WI spin echo T2WI T2WI with FS T1WI with FS	Less than 1 week
			42	17
Moreno et al.* (2017)[98]	USA	Prospective	20		58 (29–80)	Clinical, MRI, histopathology	DOI Cervical LN metastasis	T1–T4	3.0 Tesla	T1WI T2WI	1–40 days
			14	6
Baba et al. (2019)[91]	Japan	Retrospective	28		66.2±15.2 (31–86)	Clinical, MRI, histopathological	DOI Locoregional control rate Disease-free SR Overall SR	T1–T2	1.5 Tesla	T1WI T2WI T1WI with FS	NP
			18	10
Mao et al. (2019)[93]	China	Prospective	150		58.01±12.10	Clinical, MRI, histopathological	DOI Disease-specific SR Overall SR	T1–T3	1.5 Tesla	T1WI T2WI T2WI with FS	1 week
			80	70
Murakami et al. (2019)[90]	Japan	Retrospective	29		(46–87)	Clinical, MRI, histopathological	DOI Recurrence pattern	T2	3.0 Tesla	T1WI T2WI CE T1WI STIR	1 month
			15	14
Baba et al. (2019)[92]	Japan	Retrospective	45		63.4±16.1 (31–86)	Clinical, MRI, histopathological	DOI Cervical LN metastasis Locoregional control rate Disease-free SR Overall SR	T1–T2	1.5 Tesla	T1WI T2WI T1WI with FS	NP
			31	14
Vidiri et al.≤ (2020)[6]	Italy	Retrospective	43		(31–82)	Clinical, MRI, histopathological	DOI	T1–T3	1.5 Tesla	T1WI T2WI	3–4 weeks
			18	25
Ravikanth (2020)[97]	India	Prospective	30		(41–70)	Clinical, MRI, Histopathological	DOI Cervical LN metastasis	T1–T4	1.5 Tesla	T1WI T2WI	NP
			27	3
Xu et al. (2020)[87]	China	Retrospective	151		57.1 (30–78)	Clinical, MRI, histopathological	DOI Cervical LN metastasis Disease-specific SR	T1	3.0 Tesla	T1WI T2WI T2WI with FS	1 week
			111	40
Fu et al. (2020)[95]	China	Retrospective	156		58.7±9.2 (27–92)	Clinical, MRI, histopathological	DOI	T1–T3	3.0 Tesla	T1WI spin echo T2WI turbo spin echo T1WI with FS	NP
			95	61
Haraguchi et al. (2021)[88]	Japan	Retrospective	101		63.9 (22–88)	Clinical, MRI, histopathological	DOI Cervical LN metastasis	T1–T4	NP	T1WI T2WI	NP
			57	44
Baba et al. (2021)[1]	Japan	Retrospective	21		NP	Clinical, MRI, CT, histopathological	DOI	T1–T3	1.5 Tesla	T2WI T1WI with FS	NP
			16	5
Huopainen et al. (2021)[89]	Finland	Retrospective	45		NP	Clinical, MRI, histopathological	DOI	T1–T3	1.5 Tesla or 3.0 Tesla	T1WI with FS	NP
			NP
Mair et al. (2021)[100]	UK	Retrospective	60		56.7	Clinical, MRI, histopathological	DOI	T1–T4	1.5 Tesla	Post-contrast, FS T1WI	2 weeks
			40	20
Takamura et al. (2022)[8]	Japan	Retrospective	48		65.7 (23–90)	Clinical, MRI, US, histopathological	DOI	T1–T2	1.5 Tesla	T1WI with FS T2WI with FS	8–34 days
			28	20
Tang et al. (2022)[94]	China	Retrospective	122		(28–76)	Clinical, MRI, histopathological	DOI	T1–T3	3.0 Tesla	T1WI T2WI with FS DWI e-THRIVE	2 weeks
			78	44

#Patients with tongue carcinoma included in the analysis; *: the author used the term tumor thickness, which was confirmed to be DOI measurement after reading the full text

M: male; F: female; SD: standard deviation; MRI: magnetic resonance imaging; DOI: depth of invasion; NP: not provided; T1WI: T1-weighted image; T2WI: T2-weighted image; T: tumor; FS: fat suppression; CE: contrast-enhanced; STIR: short tau inversion recovery; SR: survival rate; CT: computed tomography; ≤: only mean difference was provided; LN: lymph node; US: ultrasound; DWI: diffusion-weighted image; e-THRIVE: dynamic enhanced T1 high-resolution isotropic volume examination