. 2019 Aug 22;22(1):17–30. doi: 10.1093/neuonc/noz147

Table 2.

Overview of main results derived from metabolic PET imaging and advanced MR techniques to overcome imaging challenges related to radiotherapy, ICI therapy and TT in patients with BM

	PET				Advanced MRI
	FDG	AA	AA PET Radiomics	Other Tracers	PWI	MRS	DWI	MRI Radiomics
Differentiation of radiation-induced changes from BM relapse	Diagnostic performance varies considerably^85‒90	For FET, MET, and FDOPA consistently high diagnostic performance, ^91‒98 SN and SP 80‒90%	FET PET textural feature analysis is of value,^104,105 SN and SP 80–90%	n.a.	For rCBV, thresholds and diagnostic performance vary considerably^{89,95,110–113}	Available studies suggest high SP, but low SN^112,114	ADC values seem not to be helpful^90,115	Initial results suggest high SP¹¹⁶
Identification of pseudoprogression related to ICI	n.a.	FET is potentially helpful²⁰	n.a.	n.a.	n.a.	n.a.	n.a.	n.a.
Evaluation of response to ICI or TT	n.a.	FET is of value,^73,108 reduction of tracer uptake despite unchanged MRI	n.a.	FLT is of value,¹⁰⁶ reduction of proliferative activity despite unchanged MRI	n.a.	n.a.	n.a.	n.a.
Evaluation of response to radiotherapy	n.a.	n.a.	n.a.	n.a.	Various PWI parameters allow the prediction of radiotherapy outcome^117‒120	n.a.	ADC values allow the prediction of radiotherapy outcome^122‒125	n.a.

AA = radiolabeled amino acids, ie, [¹¹C]-methyl-L-methionine (MET), 3,4-dihydroxy-6-[¹⁸F]-fluoro-L-phenylalanine (FDOPA), or O-(2-[¹⁸F]-fluoroethyl)-L-tyrosine (FET); ADC = apparent diffusion coefficient; DWI = diffusion-weighted imaging; FDG = [¹⁸F]-2-fluoro-2-deoxy-D-glucose; FLT = 3´-deoxy-3´-[¹⁸F]-fluorothymidine; MRS = MR spectroscopy; n.a. = not available; PWI = perfusion-weighted imaging; SN = sensitivity; SP = specificity.