TABLE 1.

Level of Validation Table

	Track and Domain a	MRS		CEST	T2*	PET	MRE	Criteria
		Single	CSI	APT	SWI	AA
Technical validation
Test–retest repeatability	T2							Yes, with current standard implementation	Yes, but with other implementation or patient group/animal model	None available	Unclear
Cross‐vendor reproducibility	T2							Yes, with current standard implementation	Yes, but with other implementation or patient group	None available	Unclear
Multisite reproducibility	T3							Yes, with current standard implementation	Yes, but with other implementation, or patient group, phantom, or analysis	None available	Unclear
Clinical evidence
Proof‐of‐concept in patients	C1							Differentiation of tumor types/grades	Differentiation of tumor from normal brain	None available	Unclear
Evaluated in clinical studies	C2‐3							Multiple single center	Few or preliminary studies	None available	Unclear
Evaluated in multicenter studies	C3							Good quality with relevant question	Small, preliminary or only method stability/not relevant question	None available	Unclear
Evaluated in meta‐analysis								Consistent result with standard measure	No standard measure/method, or low number of studies/patients	None available	Unclear
Established diagnostic accuracy, cut‐offs/criteria	C3							Consistent in multiple single‐center studies	Few or preliminary studies	None available	Unclear
Acceptance
Method guidelines recommendations	T							Available and updated	Available, but not updated or not specific for tumor imaging	None available	Unclear
Included in national imaging guidelines								Endorsed by a majority of the community	Only endorsed by a minority	Not mentioned	Unclear
Included in clinical trial guidelines b								Included in suggested standard protocol	Mentioned, but clinical value uncertain	Not mentioned	Unclear
Included in international clinical guidelines c								Endorsed by major international society guidelines	Mentioned, but clinical value uncertain	Not mentioned	Unclear
In clinical use for brain tumor imaging d								Widely implemented (>50%)	Intermediate (<50%)	Uncommon	Unclear
In clinical use for glioma diagnosis d								Widely applied (>50%)	Intermediate (<50%)	Uncommon	Unclear
Implementation
Sequence availability	T2							Comparable sequence available as clinical from all major vendors	No standard implementation or only WIP	Research sequence at single sites	Unclear
Postprocessing software availability	T2							On‐line scanner/reading workstation with best‐practice implementation	Off‐line, commercially available software	In‐house software	Unclear
Subjective ease of data acquisition (scanner operator)	T2							Minimal need for training	Special training/attention required	Difficult to obtain good quality data	Unclear
Subjective ease of postprocessing (within clinical department)								No postprocessing needed	Extra processing/training needed, but not time‐consuming	Expert or time‐intensive processing required	Unclear
Subjective ease of data interpretation (clinician)								Visual reading or only simple manual steps required	Special training/expertise required	Highly specialized in single centers	Unclear

References to the guidelines and also further material for each technique are included in the supplementary materials S1.

T = technical validation; C = clinical validation; Domain 1 = discovery; Domain 2 = validation; Domain 3 = Qualification.

^a Imaging biomarker roadmap.

^b RANO, iRANO, Standardized Brain Tumor Imaging Protocol.

^c GBM EANO/SNO, EANO diff. glioma, EANO glioma.

^d European survey of advanced MRI, US survey of perfusion imaging.