Contrast-enhanced MR angiography in rats with hepatobiliary contrast agents.

The aim of this animal study was to evaluate the feasibility of contrast-enhanced magnetic resonance (MR) angiography with two hepatobiliary contrast agents, Gd-DTPA-DeA and Gd-EOB-DTPA. Coronal images of the rat abdomen were acquired using a three-dimensional spoiled gradient recalled sequence before and after the administration of Gd-DTPA-DeA, Gd-EOB-DTPA, or Gd-DTPA. Four sets of postcontrast images were collected every 90 s. Contrast ratios were calculated for the abdominal aorta on the source images, and the retention index was defined as the ratio of the contrast ratio on the last imaging to that on the first postcontrast imaging. Partial minimum intensity projection (MIP) images covering the abdominal aorta were generated from the first and second postcontrast imagings, and the image quality was visually evaluated. The contrast ratio on the first postcontrast imaging was the highest for Gd-DTPA-DeA, followed by Gd-EOB-DTPA and Gd-DTPA. Retention indices were higher with Gd-DTPA-DeA than with Gd-EOB-DTPA and Gd-DTPA, implying a prolonged contrast effect with Gd-DTPA-DeA. On the MIP image from the first postcontrast imaging, delineation of the abdominal aorta tended to be better with Gd-DTPA-DeA and Gd-EOB-DTPA than with Gd-DTPA, and the difference was evident at low injection doses. Image quality for the second postcontrast imaging was higher with Gd-DTPA-DeA than with the other two agents, suggesting a longer imaging window for Gd-DTPA-DeA. In conclusion, Gd-DTPA-DeA and Gd-EOB-DTPA showed stronger contrast enhancement for the rat abdominal aorta and provided MR angiograms of higher image quality when compared with Gd-DTPA at the same injection dose. These hepatobiliary agents may make it possible to perform contrast-enhanced MR angiography even at a low injection dose.

Phantom and animal studies of a new hepatobiliary agent for MR imaging: comparison of Gd-DTPA-DeA with Gd-EOB-DTPA.

PURPOSE: To investigate the characteristics of Gd-DTPA-DeA as a hepatobiliary contrast agent for MR imaging in comparison with those of Gd-EOB-DTPA. MATERIALS AND METHODS: We undertook phantom experiments to assess T1 relaxivity for Gd-DTPA-DeA, Gd-EOB-DTPA, and Gd-DTPA in human plasma. For Gd-DTPA-DeA and Gd-EOB-DTPA, we evaluated the contrast effect in rats using an SPGR sequence. The contrast ratios of liver and abdominal aorta were measured up to 21 minutes after intravenous administration of the agents. Visualization of the bile duct and renal pelvis was also assessed. RESULTS: In human plasma, T1 relaxivity was similar for Gd-DTPA-DeA and Gd-EOB-DTPA, and higher than those for Gd-DTPA. Whereas the contrast ratio of liver peaked about five minutes after the injection of Gd-EOB-DTPA and was followed by a subsequent decline, a continuous rise was shown for Gd-DTPA-DeA, resulting in a larger maximal contrast effect. Contrast ratios of the abdominal aorta were larger for Gd-DTPA-DeA. Biliary excretion was observed for both agents but occurred earlier with Gd-EOB-DTPA. While renal excretion was shown for all rats three minutes after the injection of Gd-EOB-DTPA, it was not observed for Gd-DTPA-DeA. CONCLUSION: Gd-DTPA-DeA may be used as a hepatobiliary contrast agent and shows different pharmacokinetics from Gd-EOB-DTPA.

Interstitial magnetic resonance lymphography: comparative animal study of gadofluorine 8 and gadolinium diethylenetriamine-pentaacetic acid.

PURPOSE: We evaluated the usefulness of gadofluorine 8 (G8) and gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) for interstitial magnetic resonance lymphography (MRL). METHOD: Phantom imaging studies were conducted with G8 and Gd-DTPA corresponding to 0.1-0.005 micromol Gd/mL, and signal intensity was measured. Popliteal lymph node (PLN) accumulation was investigated in rabbits. Imaging was performed before and after subcutaneous administration of G8 (50 micromol Gd/mL) and Gd-DTPA (50 micromol Gd/mL). Contrast enhancement ratio measurements of PLN were determined both prior to and following the administration. RESULTS: Signal intensity of phantom for G8 are higher than those for Gd-DTPA from 0.1 to 0.002 micromol Gd/mL (P < 0.0001). Imaging after 5 minutes can clearly detect PLN accumulation on two contrast agents. Nevertheless, PLN accumulation of Gd-DTPA disappeared after about 30 minutes. A statistically significant difference between G8 and Gd-DTPA can be seen from 5 to 90 minutes in CER (P < 0.0001). PLN became clearly visible at 5 minutes after the injection of G8 and Gd-DTPA. Nevertheless, PLN accumulation of Gd-DTPA disappeared at 30 minutes. Otherwise, PLN accumulation of G8 continued up to 90 minutes. CONCLUSION: These studies indicated that G8 was more suitable than Gd-DTPA as a contrast agent for interstitial MRL up to 90 minutes.

Fitz-Hugh-Curtis syndrome: linear contrast enhancement of the surface of the liver on CT.

We present a case of Fitz-Hugh-Curtis syndrome (Chlamydia trachomatis perihepatitis). Contrast-enhanced CT demonstrated enhancement along the surface of the liver, but it was remarkable on the anterior surface. No other abnormalities suspicious for peritonitis were found. Contrast enhancement of the anterior surface of the liver on CT may support the diagnosis of Fitz-Hugh-Curtis syndrome.