Abnormal Findings on "T1WI or DWI or MRCP:" An Effective Boolean Interpretation Model in Discriminating Small Pancreatic Ductal Adenocarcinoma from Control Group

Abstract

Objectives: The objectives of the study was to evaluate the diagnostic performance of findings on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and magnetic resonance cholangiopancreatography (MRCP) separately and to identify an optimal Boolean interpretation model for discriminating patients with small pancreatic ductal adenocarcinoma (PDAC) from control groups in clinical practice.

Material and methods: We retrospectively enrolled 30 patients with surgery confirmed small PDAC (≤20 mm) and 302 patients without pancreatic abnormality between April 2008 and February 2020. The presence of masses was evaluated by T1WI, T2WI, and DWI. Abnormality of the main pancreatic duct (MPD) was evaluated by T2WI and MRCP. Multivariate logistic regression analysis was performed to select significant sequences for discriminating the small PDAC and control groups. Boolean operators "OR" or "AND" were used to construct sequence combinations. Diagnostic performances of these sequences and combinations were evaluated by X ² tests.

Results: The sensitivity of T2WI was lowest (20%) for detecting masses. For evaluating MPD abnormality, sensitivity was higher for MRCP than for T2WI (86.7% vs. 53.3%). Multivariate logistic regression analysis showed that T1WI and DWI for detecting the presence of masses and MRCP for evaluating MPD abnormality were significantly associated with differentiation between the two groups (P = 0.0002, P = 0.0484, and P < 0.0001, respectively). Seven combinations were constructed with T1WI, DWI, and MRCP. The combination of findings on "T1WI or DWI or MRCP" achieved the highest sensitivity of 96.7% and negative predictive value of 99.6%.

Conclusion: The combination of findings on "T1WI or DWI or MRCP" might be an optimal interpretation model for discriminating small PDAC from control groups in clinical practice.

Keywords: Boolean operators; Early diagnosis; Non-contrast magnetic resonance imaging; Pancreatic ductal adenocarcinoma; Screening.

Figure 1:

A 63-year-old man diagnosed with pancreatic ductal carcinoma by ultrasound-guided fine-needle aspiration. T1-weighted imaging shows a mass with low signal intensity in the pancreatic body (arrow) (a). T2-weighted imaging shows a mass in the pancreatic body (arrow) (b). Diffusion-weighted imaging (b value 800 s/mm²) shows a mass with high signal intensity in the pancreatic body (arrow) (c). Mild dilatation of the main pancreatic duct in the pancreatic tail (arrow) (d). The maximum intensity projection image of magnetic resonance cholangiopancreatography shows abrupt cutoff of the main pancreatic duct (arrow) with dilatation of the upstream main pancreatic duct and side branches (e).