MRI Cancer Screening and Staging

Whole-body screening for early detection of metastatic disease and whole-body staging to evaluate the extent of existing disease is critical for timely intervention and treatment. 18Fluorodeoxyglucose based positron emission tomography (FDG-PET) combined with computed tomography (PET/CT) is still the gold standard for whole-body screening and staging. However, there are concerns with limited sensitivity for certain tumors and increased exposure to ionizing radiation, particularly in younger patients with need for repeated exposures during long follow-up periods.

MRI has become an attractive approach due to the excellent soft tissue contrast combined with its lack of ionizing radiation. In recent years, diffusion-weighted imaging (DWI) using echo planar acquisitions has gained increased attention for whole-body screening, but suffers from poor signal to noise ratio (SNR) and image distortions when used with larger fields of view. Towards this goal, we are currently developing alternative approaches to DWI, using a Dual-Echo T2-weighted image for Enhanced Conspicuity of the Tumors (DETECT) with simultaneous fat, blood, and fluid suppression. Once optimized and validated in the abdomen and pelvis, we will combine this with moving table techniques for whole-body cancer screening and staging.

Echo 1 image
Echo 1 image (a) and the subtracted DETECT image (b) of a patient with a large central liver mass (arrow), compared against fat-suppressed T2-weighted image (c) and a diffusion-weighted image (b=500 s/mm2) (d). Echo 1 image (a) resembles the fat-suppressed T2-weighted image (c) and the subtracted DETECT image (b) qualitatively resembles the diffusion-weighted image (d). The dashed arrow represents the biliary ducts that are visible on the Echo 1 image (a) similar to the fat-suppressed image (c).