Feasibility and Reproducibility of Multifrequency Magnetic Resonance Elastography in Healthy and Diseased Pancreases

Abstract

Background: The feasibility and reproducibility of multifrequency MR elastography (MRE) for diagnosing pancreatic ductal adenocarcinoma (PDAC) have not been reported.

Purpose: To determine the feasibility and reproducibility of multifrequency MRE for assessing pancreatic stiffness in healthy and diseased pancreases.

Study type: Prospective.

Subjects: A total of 40 healthy volunteers and 10 patients with PDAC were prospectively recruited between March 2018 and October 2021.

Field strength/sequence: A 3.0-T pancreatic MRE at frequencies in the order of 30, 40, 60, 80, and 100 Hz.

Assessment: Body mass index (BMI) and wave distance of the healthy pancreas and PDAC were measured. Image quality was assessed using the image quality score (IQS: 1-4, ≥3 were considered diagnostic quality). Three readers independently performed the pancreatic stiffness and IQS assessments to evaluate reproducibility.

Statistical tests: Logistic regression analyses were performed to determine variables that influenced IQS. Statistical significance was set at P <0.05. Levels of inter- and intrarater agreement were assessed using intraclass correlation coefficients (ICC) and Cohen's kappa coefficient (κ). Good reproducibility was set at ICC and κ ≥ 0.8.

Results: In logistic regression analysis, a diagnostic IQS in healthy volunteers was independently associated with a lower BMI (odds ratio [OR] = 0.89 kg/m^-2 ), shorter wave distance (OR = 0.70 cm^-1 ), and lower frequency (30 and 40 Hz: OR = 170.01 and 96.02). In PDAC, frequency was the only independent factor for diagnostic IQS (30-60 Hz: OR = 46.18, 46.18, and 17.20, respectively) with 100 Hz as a reference. In healthy volunteers, good reproducibility was observed at 30 and 40 Hz. In PDAC, good reproducibility was observed at 30-60 Hz.

Data conclusion: MRE at 30 and 40 Hz provides diagnostic wave images and reliable measurements of pancreatic stiffness in healthy volunteers. MRE at 30-60 Hz is acceptable for PDACs (IQS ≥ 3, ICC and κ ≥ 0.80).

Evidence level: 1 TECHNICAL EFFICACY: Stage 2.

Keywords: elastography; magnetic resonance; pancreas; pancreatic adenocarcinoma; shear stiffness.