Correction: Journal of Medical Ultrasonics (2021) 48:555–563 https://doi.org/10.1007/s10396-021-01144-9

In the original publication of the article, the Fig. 4d was missing from this article; the figure should have appeared as shown below.

Fig. 4
figure 4

Histological sampling process. a Pushing the collected specimen onto the glass slide. b Transferring the tubular solid mass into a Petri dish filled with formalin. c Cutting and removing the white portion of the specimen with a disposable injection needle. d Placing the white mass in a container containing formalin

The original article has been corrected.