Table 4

The studies evaluating the frequency of clinically important abnormalities on head MRI in neurologically normal participants of research protocols.

Study & Year

No. of participants

(male/female)

Mean age (range)

MRI results

No referral*

Routine referral

Urgent referral

Immediate referral

Yue NC, et al. (1997) (1)

3672

> 65

3608 (98.3 %)

64 (1.7 %)

Katzman GL, et al. (1999) (2)

1000 (546/454)

30.6 (3–83)

971 (97.1 %)

18 (1.8 %)

11 (1.1 %)

0 (0 %)

Kim BS, et al. (2002) (3)

225 (100/125)

11.2 (0–18)

206 (91.6 %)

17 (8 %)

1 (< 1 %)

0 (0 %)

Illes J, et al. (2004) (14)

151 (82/69)

47.1 (18–90)

141 (93.4 %)

7 (4.6 %)

3 (2.0 %)

0 (0 %)

SD: standard deviation.

* Including the participants without any abnormal findings.

Tsushima et al. BMC Neurology 2005 5:18   doi:10.1186/1471-2377-5-18