2004
Nodules were grouped as < 1 , 1 - 3 , and > 3 cm according to their size and as hypoechoic , isoechoic , hyperechoic , or heterogeneous according to their US characteristics .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None