Differentiating carcinoma from benign causes of nonspecific gall bladder wall thickening: A prospective observational study on the role of multiparametric MRI and proposition of an MpMRI-based criteria.

Background: In nonspecific gall bladder (GB) wall thickening on ultrasonography (USG) or computed tomography (CT), the patient undergoes a more major surgery for a benign cause or a redo surgery for malignancy if diagnosed inaccurately.

Objective: To evaluate whether malignant and benign causes of nonspecific GB wall thickening can be accurately differentiated on multiparametric magnetic resonance imaging (MpMRI) and to propose MpMRI-based diagnostic criteria.

Methods: Thirty-six of 94 nonspecific GB wall thickening patients underwent MpMRI in a 1.5 T scanner. The MRI characterization was compared with histopathology. Statistical analysis calculated various MRI parameters' sensitivity, specificity, and accuracy in distinguishing benign and malignant lesions. The receiver operating curve analysis provided the apparent diffusion coefficient (ADC) cut-off value.

Results: MpMRI had 100% sensitivity and 92.31% specificity in detecting malignant wall thickening. The sensitivity and specificity of various parameters like intact mucosa on T2-weighted imaging (T2WI), smooth-enhancing mucosa, identification of wall layers on T2WI, and diffusion-weighted imaging (DWI) were 100% and 84.62%, 100% and 92.31%, 100% and 96.15%, and 100% and 53.85%, respectively, in differentiating benign from malignant thickening. Malignancy showed lower ADC values; the cut-off was 1.107 × 10-3 mm2/s. Intramural nodule/cyst on T2WI, chemical shift imaging, and dynamic contrast-enhanced MRI (DCE-MRI) showed 100% positive predictive value for benign wall thickening.

Conclusions: MpMRI accurately differentiates benign from malignant GB wall thickening and is recommended when USG or CT are inconclusive. This will help decide the type of surgery, simple cholecystectomy for benign or radical surgery for a malignant cause. Accurate prediction by MpMRI will reduce patient morbidity and improve survival.