J Korean Soc Radiol.  2020 Sep;81(5):1194-1203. 10.3348/jksr.2019.0149.

T1-Staging for Urinary Bladder Cancer with the Stalk and Inchworm Signs with 3.0 Tesla MRI

• Kim Dh
• Kang BC
• Chung J

• KMID: 2507443
• DOI: http://doi.org/10.3348/jksr.2019.0149

Abstract

Purpose
To evaluate the diagnostic utility of the stalk and the inchworm sign on preoperative MRI for detecting superficial bladder cancers, and to compare the diagnostic performance between the stalk and the inchworm sign.
Materials and Methods
We retrospectively reviewed 240 patients (505 tumors) who had undergone radical cystectomy. The tumors were classified as follows: superficial or invasive tumors indicated by the stalk or inchworm sign on 3.0 Tesla MRI. We evaluated the diagnostic accuracy of the stalk and inchworm signs, by comparing each finding with the postoperative pathologic T stage. We compared diagnostic performance between them statistically.
Results
The stalk and inchworm signs showed high specificity (93% and 91%, respectively), positive predictive values (89% and 90%, respectively), and acceptable accuracy (70% and 74%, respectively), but low sensitivity (54% and 61%, respectively) and negative predictive values (60% and 63%, respectively). There was no statistically significant difference between the two signs (p > 0.05).
Conclusion
Superficial bladder cancers could be differentiated from invasive tumors using the stalk or inchworm sign on MRI.

Keyword

Cystectomy; Urology; Urinary Bladder Cancer