title: A case of pseudomyxoma peritonei: visualization of septa using diffusion-weighted images with low b values.
abstract: Pseudomyxoma peritonei (PMP) is a rare disease with neoplastic growth of mucin-secreting cells in the peritoneal cavity, resulting in mucinous ascites. The septum of intra-abdominal fluid collection is a key imaging finding characteristic to PMP. In magnetic resonance imaging (MRI), multi-b value diffusion-weighted imaging (DWI) is a method used to obtain an accurate apparent diffusion coefficient. The clinical utilities of DWI using lower b values as diagnostic imaging are rarely highlighted. This report describes a case of PMP in which DWI using b values of 100 and 500 s/mm(2) exclusively visualized many thick septa with low signal intensity in peritoneal effusion. The septa could not be recognized in DWIs with b values of zero or 1000 s/mm(2), as with ultrasonography, computed tomography, and conventional MRI. A discrepancy between DWI using lower b values and other MRI sequences or imaging modalities indicates a specific capability of DWI using low b values: the ability to visualize septa of intra-abdominal fluid collection much thicker than in real cases. Results for this case suggest that DWI using low b values might present clinical potential for the preoperative diagnosis of PMP.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Himoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan. akikido@kuhp.kyoto-u.ac.jp.
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawada
authors.affiliation: Department of Surgery, Kishiwada City Hospital, Osaka, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kitai
authors.affiliation: Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D010534:Peritoneal Neoplasms; D011553:Pseudomyxoma Peritonei; D014057:Tomography, X-Ray Computed
keywords: DWI using lower b values; MRI; Pseudomyxoma peritonei; Septa