High b-value diffusion-weighted magnetic resonance imaging for gallbladder lesions: differentiation between benignity and malignancy
ABSTRACT 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: Potentially, diffusion-weighted magnetic resonance imaging (DWI) can assess the functional information on concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion. DWI in the hepatobiliary and pancreatic regions has demonstrated the usefulness to detect malignant lesions and differentiate them from benign lesions. However, it has been shown more recently that there is some overlap in ADC values for benign and malignant neoplasms. Moreover, some non-neoplastic lesions in the hepatobiliary and pancreatic regions exhibit restricted diffusion on DWI, because of pus, inflammation, or high cellularity. Focal eosinophilic liver disease, hepatic inflammatory myofibroblastic tumor, granulomatous liver disease, acute cholecystitis, xanthogranulomatous cholecystitis, focal pancreatitis, or autoimmune pancreatitis frequently exhibit restricted diffusion on DWI, which may be confused with malignancy in the hepatobiliary and pancreatic regions. Thus, DWI should not be interpreted in isolation, but in conjunction with other conventional images, to avoid the diagnostic pitfalls of DWI. Nevertheless, the presence of diffusion restriction in the non-neoplastic lesions sometimes provides additional information regarding the diagnosis, in problematic patients where conventional images have yielded equivocal findings. DWI may help differentiate hepatic abscess from malignant necrotic tumors, gallbladder empyema from dense bile or sludge in the gallbladder, and pylephlebitis from bland thrombosis in the portal vein. Therefore, knowledge of DWI findings to conventional imaging findings of diffusion-restricted non-neoplastic conditions in the hepatobiliary and pancreatic regions helps establishing a correct diagnosis.Abdominal Imaging 09/2014; 40(3). DOI:10.1007/s00261-014-0235-5 · 1.73 Impact Factor
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ABSTRACT: Gallbladder cancer carries an extremely high mortality rate, with a 5-year survival rate as low as 12%. Survival is dependent on the diagnosis of these tumors in their earliest stages. This study sought to describe the clinical and imaging features of stages T1, T2, and T3 gallbladder tumors and to illustrate features that may allow radiologists to make an early diagnosis. After approval from the institutional review board, a search of the pathology department database yielded 18 patients with surgically proven T1, T2, and T3 gallbladder cancers with available preoperative computed tomography (CT) or magnetic resonance imaging. The imaging was reviewed for lesional morphology (focal polyploid mass, focal wall thickening, circumferential wall thickening), enhancement characteristics, liver invasion, locoregional lymphadenopathy, and distant metastatic disease. The electronic medical record was also searched for demographic information and clinical presentation. There were 10 women and 8 men with a mean age of 69 years. Virtually all patients were symptomatic, with most patients demonstrating symptoms suggestive of underlying malignancy (including jaundice, weight loss, and chronic abdominal pain). Tumors on CT and MRI included 6 polyploid masses, 9 tumors with focal wall thickening, and 3 with circumferential wall thickening. The mean attenuation of those tumors imaged with CT was 59.4 Hounsfield units (HUs) on the arterial phase and 86.5 HUs on the venous phase, with a mean increase in Hounsfield attenuation between the arterial and venous phases of 28.2 HUs. Twelve of the 18 patients were correctly diagnosed prospectively on CT. The imaging findings of gallbladder cancer can be subtle, regardless of whether the tumor presents as a discrete mass, focal wall thickening, or circumferential diffuse wall thickening, and radiologists should be aware of the wide range of different possible appearances. Moreover, the vast majority of these patients had clinical symptoms suggestive of an underlying malignancy, and this should precipitate a careful evaluation of the gallbladder in all such cases.Journal of computer assisted tomography 03/2014; DOI:10.1097/RCT.0b013e3182aafb6b · 1.60 Impact Factor
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ABSTRACT: Background The aim of this study was to evaluate the usefulness of high b-value diffusion-weighted magnetic resonance imaging (DWI) for evaluating the histological degree of malignancy in patients with intraductal papillary mucinous neoplasm (IPMN).MethodsA total of 35 patients (mean age 68 ± 10 years, 23 males) who had undergone DWI before surgery were included in this study. Of these 35 patients, 13 had IPMN with low- or intermediate-grade dysplasia, eight had IPMN with high-grade dysplasia, and 14 had IPMN with an associated invasive carcinoma. We evaluated the positive signal rate on DWI and the apparent diffusion coefficient (ADC) value of each pathology.ResultsThe positive signal rate on DWI of IPMN with low- or intermediate-grade dysplasia, of IPMN with high-grade dysplasia, and of IPMN with an associated invasive carcinoma were 0% (0/13), 38% (3/8), and 93% (13/14), respectively. The sensitivity, specificity, and accuracy for malignancy (IPMN with high-grade dysplasia or IPMN with an associated invasive carcinoma) using DWI were 73%, 100%, and 83%, respectively. The mean ADC value of malignancy was significantly lower than that of benignity (P = 0.002).Conclusions Diffusion-weighted magnetic resonance imaging, easily applicable in addition to conventional MRI, is considered an efficient modality for evaluating the histological degree of malignancy in patients with IPMN.Journal of Hepato-Biliary-Pancreatic Sciences 11/2014; 21(11). DOI:10.1002/jhbp.135 · 2.31 Impact Factor