PET/CT hybrid imaging vs contrast-enhanced MRI with diffusion-weighted imaging in the diagnosis of liver deposits in patients with breast cancer

Introduction
Patients with breast cancer often undergo positron emission tomography-computed tomography (PET-CT) examinations for a multitude of reasons, such as staging, localizing metastasis, or early detection of recurrence. Liver deposits may present as incidental findings in such patients with underlying breast cancer. Accurate detection and diagnosis of such lesions may pose a challenge owing to the background activity of the liver.
Objective
The aim was to compare between PET-CT hybrid imaging and contrast-enhanced magnetic resonance imaging with diffusion-weighted imaging (DWI) in their capabilities to detect and/or characterize hepatic lesions encountered in patient with breast cancer, as well as to determine the cutoff values for standard uptake value with apparent diffusion coefficient.
Materials and methods
This study included 45 patient with breast cancer referred with hepatic focal lesions. All patients were females, with an age range of 30–69 years. They all underwent contrast-enhanced PET-CT and contrast-enhanced MRI with DWI. Both examinations were reviewed independently, and the results were either correlated with histopathological results of the lesions or imaging follow-up.
Results
On patient-based analysis, dynamic MRI with DWI has shown superiority over contrast-enhanced PET/CT in detecting and characterization of hepatic metastases, with sensitivity, specificity, and accuracy of 96.4, 100, and 97.7% respectively, compared with 75, 100, and 84.4%, respectively, attributed to PET/CT. Cutoff value of apparent diffusion coefficient value was 1.331×10-3 mm2/s with 98.1% accuracy. SUVmax was chosen as the main index, and a cut-off value was determined to be more than 3.84, with an accuracy of 79.14%.
Conclusion
PET/CT showed competitive results in comparison with MRI and might present itself to be a useful tool in detecting and characterizing hepatic focal lesions in patient with breast cancer.