Table I.

Characteristics of the included studies in the meta-analysis.

Study ID	First author	Year	Age (range/average)	Gender (M/F)	Study sizea	Type of lung cancer	Design	Patient enrollment	Blind	Reference standard	B-value (s/mm2)	DT of ADC (mm2/s)	Field strength	Type of scanner	Refs.
1	Chen	2010	35–76/51	35/21	56/135	NSCLC	UN	Cons	Yes	Pathology and/or follow-up	1,000	UN	1.5 T	Siemens	(14)
2	Nakayama	2010	48–82/68	38/32	70/56	NSCLC	Retro	UN	UN	Pathology	1,000	1.54×10−3	1.5 T	Siemens	(20)
3	Nomori	2008	38–82/70	47/41	88/734	NSCLC	Pros	UN	UN	Pathology	1,000	1.60×10−3	1.5 T	Phillips	(11)
4	Usuda	2013	37–83/68	94/64	158/705	Lung cancer	UN	UN	UN	Pathology	800	1.70×10−3	1.5 T	Siemens	(18)
5	Xu (ELN)	2014	42–78/55	27/15	42/33	NSCLC	Pros	Cons	Yes	Pathology	1,000	1.98×10−3	1.5 T	Phillips	(15)
6	Xu (NLN)	2014	42–78/55	27/15	42/86	NSCLC	Pros	Cons	Yes	Pathology	1,000	2.04×10−3	1.5 T	Phillips	(15)
7	Ohno	2011	61–83/73	136/114	250/270	NSCLC	Pros	Cons	Yes	Pathology	1,000	2.50×10−3	1.5 T	Phillips	(19)
8	Bai	2013	27–72/59	16/10	26/62	NSCLC	UN	UN	UN	Pathology and/or follow-up	600	1.92×10−3	1.5 T	Phillips	(21)
9	He	2013	33–77/58	27/9	36/206	Lung cancer	UN	UN	UN	Pathology	500	3.19×10−3	1.5 T	GE	(16)
10	Zhang	2013	41–72/59	17/8	25/78	NSCLC	UN	UN	Yes	Pathology	800	2.21×10−3	3.0 T	Siemens	(17)
11	Zeng	2012	48–69/58	35/10	45/68	NSCLC	UN	UN	Yes	Pathology	600	2.32×10−3	1.5 T	GE	(22)

^aNumber of enrolled patients and lymph nodes. NSCLC, non-small cell lung cancer; ELN, enlarged lymph nodes; NLN, normal-sized lymph nodes; DT, diagnostic threshold; ADC, apparent diffusion coefficient; UN, unclear; Retro, retrospective; Pros, prospective; Cons, consecutive; GE, General Electric.