High b-value diffusion-weighted magnetic resonance imaging for gallbladder lesions: Differentiation between benignity and malignancy

Department of Gastroenterology, Sendai City Medical Center, 5-22-1, Tsurugaya, Miyagino-ku, Sendai, 983-0824, Japan, .
Journal of Gastroenterology (Impact Factor: 4.52). 05/2012; 47(12). DOI: 10.1007/s00535-012-0604-1
Source: PubMed


BACKGROUND: Recently, the clinical application of diffusion-weighted magnetic resonance imaging (DWI) has been expanding to abdominal organs. However, only a few studies on gallbladder diseases have been published. The aim of this study was to evaluate the usefulness and limitations of high b-value DWI for gallbladder diseases. METHODS: A total of 153 patients (mean age 60 ± 15 years, 78 males) who had undergone DWI for evaluating gallbladder wall thickening or polypoid lesions were included in this study. Of these 153 patients, 36 had gallbladder cancer and 117 had benign gallbladder diseases (67 chronic cholecystitis, 44 adenomyomatosis, four cholesterol polyp, one gallbladder adenoma, and one xanthogranulomatous cholecystitis). We evaluated the positive signal rate with DWI and the apparent diffusion coefficient (ADC) value of each disease. RESULTS: The positive signal rate with DWI was significantly higher in gallbladder cancer (78 %) than in benign gallbladder diseases (22 %) (p < 0.001). The mean ADC value of gallbladder cancer was (1.83 ± 0.69) × 10(-3) mm(2)/s and that of benign gallbladder diseases was (2.60 ± 0.54) × 10(-3) mm(2)/s (p < 0.001). Benign gallbladder diseases with acute cholecystitis or a history of that had a higher positive signal rate with DWI (p < 0.001) and a lower ADC value (p = 0.018) than those without such conditions. CONCLUSION: DWI can contribute to the improvement of the diagnostic capability for gallbladder wall thickening or polypoid lesions by compensating for weaknesses of other modalities by its many advantages, although cases with acute cholecystitis or such history sometimes show false-positive on DWI.

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    ABSTRACT: Aim: To evaluate the benefit of diffusion-weighted imaging (DWI) in differentiating xanthogranulomatous cholecystitis from the wall-thickening type of gallbladder cancer. Materials and methods: This retrospective study was approved by the institutional review board. Fourteen patients with xanthogranulomatous cholecystitis and 19 patients with the wall-thickening type of gallbladder cancer were included. Qualitative (visual diffusion restriction compared to liver parenchyma) and quantitative [apparent diffusion coefficient (ADC)] analyses were performed. Conventional MRI findings including dynamic enhancement pattern between the two groups were also analysed. Two observers independently reviewed conventional magnetic resonance imaging (MRI) images and subsequently reviewed combined conventional MRI and DWI images. Pairwise comparison of the receiver operating characteristic (ROC) curves was used to compare diagnostic performances. Results: In conventional MRI findings, xanthogranulomatous cholecystitis showed significant continuity of enhancing mucosal line [79% (11/14) versus 26% (5/19), p = 0.003] and intramural T2-high signal intensity [64% (9/14) versus 21% (4/19), p = 0.012] compared to the wall-thickening type of gallbladder cancer. The enhancement pattern of gallbladder cancer compared to liver parenchyma showed earlier onset than that of xanthogranulomatous cholecystitis (p = 0.001). Diffusion restriction was more frequently seen in the wall-thickening type of gallbladder cancer (68%, 13/19) than in xanthogranulomatous cholecystitis (7%, 1/14; p < 0.001). The mean ADC value of xanthogranulomatous cholecystitis was higher than that of the wall-thickening type of gallbladder cancer with statistical significance (1.637 × 10(-3) mm(2)/s versus 1.076 × 10(-3) mm(2)/s, p = 0.005). Diagnostic performance [area under ROC curve (Az)] of both observers improved significantly after additional review of DWI; Az improved from 0.737 to 0.930 (p = 0.027) for observer 1 and from 0.675 to 0.938 (p = 0.008) for observer 2. Conclusion: Addition of DWI to conventional MRI improves discrimination between xanthogranulomatous cholecystitis and the wall-thickening type of gallbladder cancer.
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    ABSTRACT: Thickening of the gallbladder wall is observed in patients with gallbladder carcinoma, as well as in those with chronic cholecystitis. It is difficult to distinguish between benign and malignant gallbladder wall thickening with conventional diagnostic imaging techniques, such as abdominal ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI), particularly in patients with bile duct strictures. Currently, the fluorine-18 2-fluorodeoxyglucose positron emission tomography/CT (F-18 FDG PET/CT) scan is widely used in the differentiation of cholecystitis from gallbladder carcinoma. However, the F-18 FDG PET/CT scan may also be responsible for false-positive diagnosis. This case report focuses on a 74-year-old male who presented with thickening of the gallbladder wall and hilar bile duct stricture, originally misdiagnosed as gallbladder carcinoma by US and MRI. F-18 FDG PET/CT also demonstrated increased activity. This case was ultimately proven to be chronic cholecystitis by postoperative pathological examination and it is presented in order to emphasize the significance of considering the possibility of false-positive diagnosis by PET/CT, as a result of inflammatory lesions. Therefore, PET/CT should not be considered the gold standard for the discrimination between benign and malignant gallbladder wall thickening.
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    ABSTRACT: To investigate the value of diffusion-weighted imaging (DWI) for differentiating benign from malignant gallbladder lesions. One hundred and twenty-six patients who had undergone magnetic resonance imaging (MRI) with DWI, in whom the histopathological diagnosis of their gallbladder lesions was confirmed by biopsy or surgery were retrospectively analysed. Thirty-six malignant and 90 benign lesions were included. Two radiologists categorized gallbladder lesions into seven types on two imaging sets [T2-weighted imaging (WI) alone and combined T2WI and DWI (b = 800 s/mm(2))] according to the presence of wall thickening, layered patterns, morphology of the mass, and diffusion restriction. Disagreements were resolved in consensus. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging set for diagnosing gallbladder carcinoma were calculated. The diagnostic performance of each imaging set was calculated using receiver operating characteristic (ROC) curve analysis. Additionally, ADC values of malignant and benign gallbladder lesions were compared separately for 1.5 and 3 T MRI. The sensitivity, specificity, PPV, and NPV of diagnosis at T2WI were 97.2%, 86.7%, 74.5%, and 98.7%, respectively. The sensitivity, specificity, PPV, and NPV using combined T2WI and DWI were 97.2%, 92.2%, 83.3%, and 98.8%, respectively. Diagnostic accuracy for gallbladder carcinoma slightly improved after adding DWI, from 0.92 to 0.95 (p < 0.05). ADC values for gallbladder carcinoma were significantly lower than those for benign lesions. Mean ADC values of malignant and benign lesions were 0.97 ± 0.25 × 10(-3) and 1.72 ± 0.56 × 10(-3) mm(2)/s, respectively, at 1.5 T (p < 0.001), and 1.04 ± 0.38 × 10(-3) and 2.2 ± 0.72 × 10(-3) mm(2)/s, respectively, at 3 T (p < 0.001). DWI can improve diagnostic accuracy for differentiating benign from malignant gallbladder lesions.
    Clinical Radiology 11/2013; 69(2). DOI:10.1016/j.crad.2013.09.017 · 1.76 Impact Factor
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