Abstract. Differentiation between adenomyomatosis (ADM) and cancer of the gallbladder is necessary during diagnosis. Diffusion-weighted whole body imaging with background body signal suppression (DWIBS) images are able to indicate cancer and inflammation. The fusion of a DWIBS with a T2 weighted image (DWIBS/T2) facilitates both functional and anatomical investigations. In the present study, patient records and images from patients with surgically confirmed ADM from April 2012 to October 2014 were analyzed retrospectively. The enrolled patients, including 6 men (64.2±13.1 years) and 4 women (57.3±12.4 years) were subjected to DWIBS/T2 during routine clinical practice. The diagnosis of ADM was based on magnetic resonance cholangiopancreatography, transabdominal ultrasonography, and endoscopic ultrasonography; ADM was diagnosed definitively when cystic lesions were observed, indicating the Rokitansky-Aschoff sinus. A single patient was indicated to be positive by DWIBS/T2 imaging. The Rokitansky-Aschoff sinus revealed a relatively high signal intensity; however, it was not as strong as that of the spleen. The signal intensity was also high on an apparent diffusion coefficient map, suggesting T2 shine-through. The thickened wall displayed low signal intensity. The aforementioned results indicate that ADM may be negative upon DWIBS/T2 imaging; one false positive case was determined to be ADM, accompanied by chronic cholecystitis. The majority of patients with ADM displayed negative findings upon DWIBS/T2 imaging, and chronic cholecystitis may cause false positives.
IntroductionAdenomyomatosis of the gallbladder (ADM) is defined as the epithelial proliferation and hypertrophy of the muscles of the gallbladder wall (1). An outpouching of the gallbladder mucosa into the thickened muscular layer is termed Rokitansky-Aschoff sinus (2). ADM may be further divided into three subtypes: Fundal, segmental and diffuse (3). A major challenge in ADM diagnosis arises from the difficulty in distinguishing the disease from gallbladder cancer (4).Recent advances in diagnostic imaging have improved the distinction between ADM and gallbladder cancer. Contrast-enhanced endoscopic ultrasonography (EUS) is beneficial for the differential diagnosis of gallbladder wall thickening (5). High-resolution ultrasound is also advantageous for differentiating gallbladder cancers from ADM (6); however, the challenge of differentiating gallbladder cancer from ADM has yet to be resolved. A primary cause of the challenge is intratumoral cystic components, which create difficulty in discerning between gallbladder cancer and ADM (7).Diffusion-weighted whole body imaging with background body signal suppression (DWIBS) images are acquired through multiple-signal averaging, pre-pulse fat suppression, and heavy diffusion weighting during free breathing (8); DWIBS is based upon diffusion-weighted imaging (DWI), which visualizes and assesses the random movement of water at the molecular level (Brownian motion) (9,10). An advantage of DWIBS is that it provides...