Assessment of Arterial Involvement in Pancreatic Cancer: Utility of Reconstructed CT Images Perpendicular to Artery.

The purpose of this study was to investigate the utility of reconstructed CT images perpendicular to the artery for assessing arterial involvement from pancreatic cancer and compare the interobserver variability between it and the current diagnostic imaging method. This retrospective study included patients with pancreatic cancer in the pancreatic body or tail who underwent preoperative pancreatic protocol CT and distal pancreatectomy. Five radiologists used axial and coronal CT images (current method) and perpendicular reconstructed CT images (proposed method) to determine if the degree of solid soft-tissue contact with the splenic artery was ≤180° or >180°. The generalized estimating equations were used to compare the diagnostic performance of solid soft-tissue contact >180° between the current and proposed methods. Fleiss' ĸ statistics were used to assess interobserver variability. The sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° were higher (p < 0.001 for each) and the specificity (p = 0.003) and positive predictive value (p = 0.003) were lower in the proposed method than the current method. Interobserver variability was improved in the proposed method compared with the current method (ĸ = 0.87 vs. 0.67). Reconstructed CT images perpendicular to the artery showed higher sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° than the current method and demonstrated improved interobserver variability.

MRI findings of sporadic/simple lymphoepithelial cyst of the parotid gland.

PURPOSE: This study aimed to determine the MRI features of sporadic/simple lymphoepithelial cyst (SLEC) of the parotid gland. METHODS: Ten patients (seven men, three women; mean age, 60 years; age range, 38-77 years) with histopathologically and clinically proven SLEC of the parotid gland who underwent MRI before surgical resection were enrolled in this study. No enrolled patient had HIV infection or Sjögren syndrome. MRI findings of SLEC were retrospectively assessed. RESULTS: We confirmed 10 SLECs larger than 10 mm with a mean maximum diameter of 26.6 mm (range, 12-42 mm). Nine patients (90%) had a single cyst, and one (10%) had a large cyst accompanied by small cysts (<10 mm) within the ipsilateral parotid gland. Eight SLECs (80%) were unilocular, and two (20%) were bilocular, with complete septa. Among seven SLECs (70%) with internal septa, five unilocular SLECs (50%) had incomplete septa. Six SLECs (60%) had eccentric cyst wall thickening, and five (50%) were surrounded by small solid nodules that were isointense relative to lymph node. On T1-weighted images, all cyst contents were homogeneously hyperintense relative to cerebrospinal fluid. CONCLUSION: SLECs of the parotid gland are usually single unilocular lesions. Internal septa, eccentric cyst wall thickening, and small solid nodules surrounding the lesion were often observed. Cyst contents are always homogeneously hyperintense on T1-weighted images.

MRI findings of epithelial-myoepithelial carcinoma of the parotid gland with radiologic-pathologic correlation.

PURPOSE: This study aimed to describe the MRI findings of epithelial-myoepithelial carcinoma (EMC) of the parotid gland. MATERIALS AND METHODS: Seven patients (four males and three females) aged 40-86 years (mean age, 64 years) with histologically proven EMC of the parotid gland who underwent surgical resection after preoperative MRI were enrolled. MRI images were retrospectively reviewed and contrasted with pathological findings. RESULTS: Five patients (71%) had predominantly solid lesions, and two (29%) had predominantly cystic lesions. All seven lesions had well-demarcated margins and capsules without the invasion of adjacent structures. The capsules were incomplete in five lesions (71%) and complete in two (29%). Four lesions (57%) exhibited a multinodular structure with internal septa. Cystic components were observed in three lesions (43%). On T1-weighted images, the solid components were frequently homogeneous (5/7, 71%), and demonstrated isointensity in five lesions (71%) and hypointensity in two (29%) relative to the spinal cord. On T2-weighted images, the solid components were usually heterogeneous (6/7, 86%), and demonstrated hyperintensity in five lesions (71%) and isointensity in two (29%) relative to the spinal cord. The mean apparent diffusion coefficient value of the solid components was 0.967 × 10-3 mm2/s. CONCLUSION: Parotid gland EMCs usually appeared as predominantly solid lesions with well-demarcated margins and capsules. A multinodular structure with internal septa was characteristics of EMCs.