CT diagnosis of gallbladder adenomyomatosis: importance of enhancing mucosal epithelium, the "cotton ball sign"

Eur Radiol. 2018 Sep;28(9):3573-3582. doi: 10.1007/s00330-018-5412-4. Epub 2018 Apr 9.

Abstract

Objectives: To determine the diagnostic value of the cotton ball sign and other CT features in patients with gallbladder (GB) wall thickenings (WTs).

Methods: Three blinded readers reviewed the preoperative CT and MR images of 101 patients with pathologically confirmed GB adenomyomatosis (GA) (n = 34) and other benign (n = 29), malignant (n = 41), and premalignant (n = 2) GBWTs. Three readers analysed the morphological features of GBWT and presence of the "cotton ball sign", defined as fuzzy grey dots in GBWT or a dotted outer border of the inner enhancing layer on contrast-enhanced (CE) CT. In addition, the "pearl necklace sign" on MR was analysed.

Results: In the GA group (n = 34), prevalence of the cotton ball sign and pearl necklace sign was 74% (25/34) and 44% (15/34), respectively. Presence of the cotton ball sign, smooth contour of the mucosa, double-layering enhancement, and enhancement degree weaker than the renal cortex on CT images were significant predictors of benign GBWT (p < 0.01). When differentiating GA from GB malignancy or premalignancy, accuracy of the cotton ball sign and pearl necklace sign was 81% (62/77) and 74% (57/77), respectively.

Conclusion: The cotton ball sign on CE-CT showed higher sensitivity and comparable specificity to those of the pearl necklace sign in differentiating GA from malignancy.

Key points: • Prevalence of the cotton ball sign on CT was 74% in gallbladder adenomyomatosis. • The cotton ball sign was useful in differentiating gallbladder adenomyomatosis from gallbladder cancer. • The cotton ball sign was more sensitive than the pearl necklace sign for adenomyomatosis diagnosis.

Keywords: Adenomyoma; Diagnosis, differential; Gallbladder diseases; Gallbladder neoplasms; Tomography, X-ray computed.

MeSH terms

  • Adenomyoma / diagnostic imaging*
  • Adult
  • Aged
  • Aged, 80 and over
  • Diagnosis, Differential
  • Epithelium / diagnostic imaging
  • Female
  • Gallbladder / diagnostic imaging
  • Gallbladder Neoplasms / diagnostic imaging*
  • Humans
  • Image Interpretation, Computer-Assisted / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Mucous Membrane / diagnostic imaging
  • Precancerous Conditions / diagnostic imaging
  • Retrospective Studies
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / methods
  • Young Adult