Table 2 MRI features of 9 meningiomas and 13 schwannomas less than 2.5 cm in size

Tumor size (cm)

1.69 ± 0.46 (1.1–2.5)

1.98 ± 0.59 (0.5–2.5)

0.095

Tumor side (left)

3 (33.33)

9 (69.23)

0.192

Signal intensity

T1

0.409

Hyperintensity

1 (11.11)

0 (0.0)

Hypointensity

8 (88.89)

13 (100.0)

T1 + C

Contrast enhancement

9 (100.0)

13 (100.0)

1

T2

0.616

Hyperintensity

8 (88.89)

10 (76.92)

Hypointensity

1 (11.11)

3 (23.08)

DWI/ADC

Restricted diffusion

5 (55.56)

1 (7.69)

0.023

ADCmin—10⁻⁶ mm²/s

750.022 ± 381.242 (86.1–1144.4)

1365.992 ± 623.02 (355.7–2616.6)

0.002

ADC—Tumor/contralateral white matter ratio

1.22 ± 0.226 (0.96–1.623)

1.637 ± 0.62 (0.497–3.089)

0.008

DWI—Tumor/contralateral white matter ratio

1.413 ± 0.448 (0.891–2.36)

0.797 ± 0.366 (0.299–1.801)

0.001

Tumor morphology

Dural tail

4 (44.44)

0 (0.0)

0.017

Dumbbell shape

3 (33.33)

4 (30.77)

1

Cyst

0 (0.0)

5 (38.46)

0.054

Masticatory muscle thickness

Tumor side (mm)

6.56 ± 1.96 (2.6–9.0)

5.68 ± 0.81 (4.2–6.8)

0.041

Contralateral side (mm)

6.22 ± 2.17 (1.4–8.6)

6.54 ± 1.41 (5.0–10.0)

0.447

Atrophy change (%)^*

−13.0 ± 26.0 (−86.0 ~ 3.0)

11.0 ± 12.0 (−14.0–38.0)

 < 0.001