Differentiating gallbladder cancer from polyps using non-enhanced magnetic resonance imaging

Area of Science:

• Radiology
• Oncology
• Gastroenterology

Background:

• Gallbladder cancer (GBC) requires accurate differentiation from benign gallbladder polyps (GBPs) for appropriate management.
• Non-enhanced magnetic resonance imaging (MRI) is increasingly explored for its diagnostic capabilities in abdominal pathologies.

Purpose of the Study:

• To evaluate the diagnostic performance of non-enhanced MRI in distinguishing GBC from GBPs (≥ 10 mm).
• To identify imaging features on MRI that predict malignancy in gallbladder lesions.

Main Methods:

• Retrospective cohort study including patients with GBC or GBPs (≥ 10 mm).
• Two blinded readers assessed continuity of mucosal and muscular layers (CMML) and normalized signal intensity ratio (NIR) on ADC, T1WI, and T2WI MRI sequences.
• Logistic regression and ROC analyses were used to determine predictive variables and diagnostic performance.

Main Results:

• Multivariate analysis revealed significant differences in CMML, NIR-ADC, and NIR-T1WI between GBC and GBPs (p < 0.001).
• Absence of CMML demonstrated high positive predictive value (~100%) and specificity.
• Combining CMML assessment with NIR-ADC improved sensitivity to ~70% compared to CMML alone (~50%).
• Combined assessment of tumour size and CMML outperformed tumour size alone in diagnostic performance.

Conclusions:

• The absence of CMML and a NIR-ADC value ≤ 1.86 are key indicators for differentiating GBC from GBPs.
• Integrating CMML evaluation with tumour size measurement offers superior diagnostic accuracy compared to size measurement alone.