Background/aim: A novel mathematical diagnostic analysis using Fourier transform (FT) algorithm of the extrahepatic bile duct (BD) using magnetic resonance-cholangiography (MRC) was performed to evaluate irregularities of the bile duct lumen indicating BD cancer (BDC) extension compared to pancreatic head malignancies controls.
Patients and methods: BD lumen was automatically traced, and a 2D-diagram cross-section was measured and a FT-based integrated-power-spectral-density-function value (FTV) of both diameter and area (mm 2 and mm 4 /Hz) was calculated for cancerous and non-cancerous parts utilizing a computer workstation.
Results: FT analysis that was achieved in 59 patients consisted of BDC in 31, pancreatic cancer with biliary stenosis (PC) in 10 and pancreatic neoplasm without stenosis (PN) in 18. FTV-diameter and -area of non-tumorous proximal BD were larger compared to tumor involving BD (p<0.01), and those of the entire BD in BDCs were significantly larger than those in PN (p<0.01). FTV-diameter and -area in proximal BDC-positive were smaller than those in BDC-negative (p<0.05). BDC part was significantly discriminated by the cutoff value (286 mm 2 Hz -1 in diameter and 10,311 mm 4 Hz -1 in area) compared to PC and diagnostic accuracy was over 70% (p<0.01).
Conclusion: Novel mathematical MRC FT-analysis is promising for differentiating between BDC and PC with biliary stenosis and can be utilized as an objective diagnostic tool in the future.
Keywords: Bile duct carcinoma; Fourier transform; cancer extension; differential diagnosis; magnetic resonance cholangiography; malignant biliary stenosis.
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