Computed Tomography-based Morphological Differences between Histologic Subtypes of Periampullary Ductal Adenocarcinoma.

OBJECTIVE: To evaluate the computed tomography (CT)-based differences between pancreaticobiliary (PBST) and intestinal (IST) subtypes of periampullary pancreatic ductal adenocarcinomas (PDAC). STUDY DESIGN: Analytical study. PLACE AND DURATION OF STUDY: Faculty of Medicine, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Turkey between 2015 and 2018. METHODOLOGY: Overall 24 periampullary PDAC cases, in whom histomorphologic evaluation and CDx2 expression were used to discriminate between PBST and IST, were included. The lesion morphology (infiltrative versus nodular), common bile and main pancreatic ducts' dilation, tumor grade, enhancement pattern, pancreaticoduodenal groove, pancreaticoduodenal artery and lymphatic involvement were evaluated by CT. RESULTS: Overall 24 PDAC cases [median age 67.5 (60.5-76.5) years] were enrolled. Histopathology revealed 9 (25%) IST and 18 (75%) PBST. The age [72.5 (69-81) versus 63 (57.75-75.5) years, respectively, p=0.204] and gender [3 (50%) versus 12 (66.7%) males, respectively, p=0.635] and the prevalence of all CT characteristics were similar between groups (p>0.05 for all) except for lesion morphology. Infiltrative morphology was more frequent in PBST than IST [14 (77.8%) versus 1 (16.7%), respectively, p=0.015]. Multiple variable logistic regression analysis revealed infiltrative morphology as the only independent CT predictor of PBST [OR: 14.9, 95% CI: 1.2-186), p=0.036]. The interrater reproducibility for lesion morphology was moderate (Cohen's Kappa: 0.55, p<0.007). CONCLUSION: Infiltrative appearance is associated with PBST; whereas, nodular appearance more likely predicts IST. The potential role of CT lesion morphology on guiding appropriate chemotherapy in cases with no chance for surgery or biopsy requires addressing. Key Words: Intestinal differentiation, Pancreatobiliary differentiation, Periampullary adenocarcinoma.

Role of iliac crest tangent in correct numbering of lumbosacral transitional vertebrae

Background/aim: The iliac crest tangent (ICT) has recently emerged as a reliable landmark to correctly number the lumbosacral transitional vertebrae (LSTV). We retrospectively evaluated the reproducibility and accuracy of the ICT as a landmark in subjects without disc degeneration. Materials and methods: Fifty-eight patients with LSTV [19 female, 41 (26­52) years] and 55 controls without LSTV [23 female, 40 (26­55) years] who had undergone spinal computed tomography were included. The ICT was drawn on the coronal images, with the cursor in the sagittal view set to the posterior ⅓ of the vertebral body located one level above the LSTV. When more than 1.25 vertebral body was counted below the ICT, the LSTV was considered as S1, otherwise it was considered as L5. The gold standard was counting the vertebrae craniocaudally. Results: The interobserver agreement was good for determining ICT level (Cohen's kappa = 0.78, P < 0.001). The rate of correct numbering by ICT in the LSTV group was significantly less than in the controls (43.1% vs. 96.4%, respectively, P < 0.001). Patients with sacralization had a significantly lower correct numbering rate than patients with lumbarization (33.3% vs. 63.2%, respectively, P = 0.03). Conclusion: ICT does not seem to be a reliable landmark for correct numbering of LSTV in patients with no intervertebral disc degeneration.