Inter- and intra-observer variability of computed tomography-based parenchymal- and ductal diameters in chronic pancreatitis: a multi-observer international study.

PURPOSE: The need for incorporation of quantitative imaging biomarkers of pancreatic parenchymal and ductal structures has been highlighted in recent proposals for new scoring systems in chronic pancreatitis (CP). To quantify inter- and intra-observer variability in CT-based measurements of ductal- and gland diameters in CP patients. MATERIALS AND METHODS: Prospectively acquired pancreatic CT examinations from 50 CP patients were reviewed by 12 radiologists and four pancreatologists from 10 institutions. Assessment entailed measuring maximum diameter in the axial plane of four structures: (1) pancreatic head (PDhead), (2) pancreatic body (PDbody), (3) main pancreatic duct in the pancreatic head (MPDhead), and (4) body (MPDbody). Agreement was assessed by the 95% limits of agreement with the mean (LOAM), representing how much a single measurement for a specific subject may plausibly deviate from the mean of all measurements on the specific subject. Bland-Altman limits of agreement (LoA) were generated for intra-observer pairs. RESULTS: The 16 observers completed 6400 caliper placements comprising a first and second measurement session. The widest inter-observer LOAM was seen with PDhead (± 9.1 mm), followed by PDbody (± 5.1 mm), MPDhead (± 3.2 mm), and MPDbody (± 2.6 mm), whereas the mean intra-observer LoA width was ± 7.3, ± 5.1, ± 3.7, and ± 2.4 mm, respectively. CONCLUSION: Substantial intra- and inter-observer variability was observed in pancreatic two-point measurements. This was especially pronounced for parenchymal and duct diameters of the pancreatic head. These findings challenge the implementation of two-point measurements as the foundation for quantitative imaging scoring systems in CP.

A huge retroperitoneal cyst with a rare clinical presentation.

A 39-year-old male presented with deep venous thrombosis in the right lower limb. He had been experiencing increasing abdominal girth over several years, but this went undetected at the initial examination. Eighteen months later, a computed tomography was conducted, showing a huge retroperitoneal cyst (25 × 23 × 16 cm) lifting the right external iliac vessels. Complete surgical excision of the cyst was performed. The cyst was unilocular and contained 5 l of clear fluid. Histopathology examination found a thin cyst wall consisting of fibrous stromal tissue with a single-layer epithelium lining. Immunohistochemical staining revealed positivity for endothelial cell markers, CD31 and CD34, but negativity for the lymphatic marker podoplanin (D2-40), corresponding to a vascular origin, likely a venous malformation.