Optimization of Gd-DTPA-enhanced balanced turbo field echo sequence in abdominal imaging: A basic study

Purpose: To determine the optimum imaging conditions for the balanced turbo field echo (bTFE) sequence in abdominal imaging, we performed phantom experiments and scanning of a normal volunteer while noting the correlation among signal intensity, k-space ordering, flow velocity and Gd-DTPA concentration. Materials and Methods: Initially, the abdomen of a healthy volunteer and some samples (water, blood and bovine albumin solutions with various Gd-DTPA concentrations, and olive oil) were examined with the bTFE sequence under various conditions to define the correlation among signal intensity, k-space ordering and Gd-DTPA concentration. Another experiment was performed to assess the correlation between the flow velocity and Gd-DTPA concentration. With the centric-bTFE sequence, we measured the signal intensity of water samples having various Gd-DTPA concentrations flowing in a long tube with an internal diameter of 4 mm. Results: The experiments revealed the following issues: (i) The contrast of bTFE images was much influenced by k-space ordering; (ii) Gd-DTPA did not exhibit an overt enhancement effect in water and blood under stable conditions; (iii) The signal intensity of moving water decreased in centric-bTFE images, and this signal drop became more significant as the fluid speed increased; and (iv) Gd-DTPA decreased the range of signal loss in the moving fluid; however, this effect had no correlation with Gd-DTPA concentration. Conclusion: When the bTFE sequence was employed for abdominal imaging, centric view ordering, fat suppression and Gd-DTPA contrast enhancement were assumed to be necessary.