Acquisition of a viable tissue sample is critical to success of percutaneous biopsy. MRI offers a unique diffusion-weighted imaging (DWI) contrast mechanism sensitive to microstructural tissue properties and that differentiates between viable and necrotic tissue ¹. Unfortunately, the commonly used echo planar imaging (EPI) DWI technique is not well-suited for biopsy. The EPI geometric distortions of patient's anatomy result in an erroneous impression of the relative position between the tumor and the needle entry point. Furthermore, the artifact produced by a biopsy needle makes the DWI image difficult to interpret and to guide further needle advancement. Hence, the DW-PROPELLER technique, much less sensitive to local magnetic field variations and motion than EPI, was previously proposed for biopsy guidance and the feasibility of selective positioning of a biopsy needle within a viable region of the tumor was demonstrated in a VX2 rabbit tumor model ¹. However, despite the benefits of the DW-PROPELLER, long acquisition time of this technique diminishes its role in an interventional setting. DW Dual Echo Steady State (DW-DESS) sequence ², on the other hand, allows acquisition of 3D high resolution DW images without EPI distortions and requires shorter acquisition times compared to PROPELLER. Motion sensitivity of DESS, however, precluded the development of this technique in the abdomen ^2-4. Motivated by successful application of DESS in a motion susceptible setting, e.g., breast imaging ², the study aimed to evaluate the application of DW-DESS during an MR-guided liver biopsy.This study was approved by the institutional review board. All human subjects were scanned with written, informed consent. Imaging was performed on a GE 1.5 T MR450w scanner (GE Healthcare, Waukesha, WI) using a 12-channel phased-array torso Radiofrequency coil. The diffusion sensitivity of the DESS sequence was adjusted by modifying the spoiler gradient area in the slice direction. Imaging in a volunteer liver was used to determine parameters enabling a single breath-hold image acquisition. The motion artifacts were compared between sequential and elliptic-centric phase encode ordering. Patient scans were carried out in two subjects undergoing routine MR-guided liver biopsy using a titanium-alloy 16G coaxial introducer needle and an 18G semi-automatic biopsy gun (InVivo, Germany). An interventional radiologist navigated the needle to the target using intra-procedural imaging with LAVA-Flex sequence without a breath-hold in subject 1 and with a breath-hold in subject 2. Breath-hold DESS images were acquired before and after the biopsy needle was introduced in patients 1 and 2, respectively. In patient 1, a DW-DESS image of a lesion was compared to a previously-obtained diagnostic EPI-DWI. In patient 2, lesion appearance in the presence of biopsy needle and the artifact of the needle were compared between DESS and LAVA (no EPI-DWI images were available). No fat suppression was applied in DW-DESS. Table 1 summarizes patient details and imaging parameters.The application of DESS to image the liver in a volunteer showed that using an acquisition matrix of 256x160x16 with minimum repetition time, scan time could be reduced to 27 seconds, enabling single breath-hold image acquisition. Motion artifacts present in the second echo (TE2) image during a breath-hold acquisition with a spoiler area of 2 cycles per voxel (Figure 1) showed the benefit of elliptic-centric phase ordering compared to sequential ordering. The boundaries of a cyst could be well-delineated in both cases. In patient 1, compared to the diagnostic EPI-DWI image, the lesion appeared sharper, less blurred and distorted on the high DW DESS image (Figure 2). Decreased signal intensity area was observed posterior to the tumor (Figure 2c), potentially due to bulk motion. In patient 2, the biopsy needle artifact seen in a high DW DESS image was found comparable to the one in the LAVA-Flex image (Figure 3). Moreover, despite the small size of the tumor, the position of the biopsy needle could be clearly visualized on the DW-DESS image. In this study, we performed a preliminary qualitative evaluation of DW-DESS in a setting of MRI-guided liver biopsy. The demonstrated capability to acquire a DW image during a single breath-hold makes DESS a feasible technique for DWI of the abdomen. Similar to breath-hold imaging in general, successful DESS imaging will be limited by the patient’s ability to follow breath-hold instruction, sometimes impaired in sedated patients. Diffusion sensitivity of DESS will be optimized in future patients to demonstrate differentiation between viable and necrotic tissue. The lack of geometric distortion, higher resolution, acceptable biopsy needle artifact and short acquisition times of DW-DESS can help transform MRI-guided biopsy from a macroscopically to a microscopically targeted procedure and reduce biopsy sampling errors.