Gallbladder wall thickening: significance of hyperintense spots visualized on T2-weighted MR imaging

Objective: To study the characteristics of hyperintense spots on MR imaging in patients with pathologically confirmed gallbladder adenomyomatosis, chronic cholecystitis and gallbladder carcinoma. Methods: MR imaging of 38 patients (15 male and 23 female, age range 30 to 78 years old, mean 55 years) with gallbladder adenomyomatosis (n=16), chronic cholecystitis (n=13) and gallbladder adenocarcinoma with mural thickening (n=9) was analyzed. For each patient, conventional T1WI and T2WI with 7 mm slice thickness, thin-slice T2WI with 3 mm slice thickness, and single shot fast spin-echo MRCP were obtained. All patients underwent cholecystectomy. Two radiologists correlated the features of hyperintense spots on T2-weighted MR imaging and histopathological findings out of the specimen after surgery; in addition, hyperintense spots were scored according to a five-point scale system. Results: Focal or diffuse gallbladder wall thickening (thickness ranged from 5 mm to 15 mm, mean 9 mm) with hyperintense spots was found in all cases. Some differences of hyperintense spots in signal intensity, location, shape, number, diameter, and border were identified within the thickened wall of the gallbladder among the three diseases. Scores on a five-point confidence scale for evaluating the hyperintense spots were 4.78±0.19, 4.79±0.23, and 2.71±0.21, respectively, in gallbladder adenomyomatosis, chronic cholecystitis, and gallbladder adenocarcinoma with mural thickening. Statistically, the benign gallbladder wall thickening had significantly higher scores than the malignant (P<0.001, q test). Scores between gallbladder adenomyomatosis and chronic cholecystitis were not statistically significant (P=0.885, q test). Conclusion: Correctly identifying the features of hyperintense spots on T2-weighted MR imaging should be helpful for distinguishing benign gallbladder wall thickening from the malignant. (authors)