Shi et al [18] 81 S 65% (53/81) 17% (14/81) - 35% (28/81) 4% (3/81) 10% (8/81) 47% (38/81) - 11% (9/81) 32% (26/81) 5% (4/81) - 6% (5/81) - 6% (5/81) - Cystic change 10% (8/81)