Prospective study of 11C–methionine PET for distinguishing between recurrent brain metastases and radiation necrosis: limitations of diagnostic accuracy and long-term results of salvage treatment

Table 2 Difference in clinical characteristics between MET-PET diagnosis groups

Characteristic	LNR ≥ 1.4 (n = 19)	LNR < 1.4 (n = 13)	P value
Sex (male/female)	12/7	7/6	0.72
Age^a (years), median (range)	67 (14–87)	63 (49–79)	0.45
KPS^a, median (range)	80 (50–100)	90 (60–100)	0.26
Neurological deficit^a	15 (79%)	9 (69%)	0.011
RTOG-RPA Class^a (I/II/III)	4/11/4	4/7/2	0.79
Multiple BM^a	11 (58%)	5 (38%)	0.47
Repeat prior radiotherapy	7 (37%)	6 (46%)	0.72
Time from primary radiotherapy to MET-PET (months), median (range)	14.3 (4–120)	24.9 (6–111)	0.046

MET-PET ¹¹C–methionine positron emission tomography, LNR lesion/normal ratios, KPS Karnofsky performance status, RTOG radiation treatment oncology group, RPA recursive partitioning analysis, BM brain metastases, ^aupdated status at the time of MET-PET

ISSN: 1471-2407