Gd complexes of macrocyclic diethylenetriaminepentaacetic acid (DTPA) biphenyl-2,2'-bisamides as strong blood-pool magnetic resonance imaging contrast agents.

We report the synthesis of macrocyclic DTPA conjugates of 2,2'-diaminobiphenyl and their Gd complexes of the type [Gd(L)(H(2)O)]·xH(2)O (2a,b; L = 1a,b) for use as new MRI blood-pool contrast agents (MRI BPCAs). Pharmacokinetic inertness of 2 compares well with those of analogous Gd-DTPA MRI CAs currently in use. The present system also shows very high stability in human serum. The R(1) relaxivity reaches 10.9 mM(-1) s(-1), which is approximately 3 times as high as that of structurally related Gd-DOTA (R(1) = 3.7 mM(-1) s(-1)). The R(1) relaxivity in HSA goes up to 37.2 mM(-1) s(-1), which is almost twice as high as that of MS-325, a leading BPCA, demonstrating a strong blood pool effect. The in vivo MR images of mice obtained with 2b are coherent, showing strong signal enhancement in heart, abdominal aorta, and small vessels. Even the brain tumor is vividly enhanced for an extended period of time. The structural uniqueness of 2 is that it is neutral in charge and thus makes no resort to electrostatic interaction, supposedly one of the essential factors for the blood-pool effect.

Gd-complexes of macrocyclic DTPA conjugates of 1,1'-bis(amino)ferrocenes as high relaxivity MRI blood-pool contrast agents (BPCAs).

We report the synthesis of macrocyclic DTPA conjugates of 1,1'-bis(amino)ferrocenes (1a-b) and their Gd-complexes [Gd(L)(H(2)O)] (2a-b, L = 1a-b) for use as new MRI blood-pool contrast agents. High R(1) relaxivity in HSA as well as high thermodynamic and kinetic stabilities is observed for 2a.

Percutaneous paracoccygeal catheter drainage of deep pelvic abscesses using a combination of sonographic and fluoroscopic guidance.

BACKGROUND: The purpose of this study is to demonstrate the feasibility, safety, and success of percutaneous paracoccygeal catheter drainage of deep pelvic abscesses using a combination of sonography and fluoroscopic guidance. METHODS: From April 2005 to December 2006, under sonography and fluoroscopic guidance, sixteen patients with deep pelvic abscess underwent percutaneous paracoccygeal drainage. The causes of pelvic abscesses were post-operative complications. The patient was in prone position; the puncture site was first evaluated with sonography. After local anesthesia, a thin needle (22 G) was positioned along the lateral margin of the coccyx to avoid an eventual injury of sciatic nerve or vessels into the deep pelvic abscess under sonography guidance. Small dose of contrast was injected under fluoroscopy to verify the needle. With Seldinger technique catheters were placed for drainage. Catheter drainage was maintained for 9-40 days. Patients underwent clinical follow-up and subsequent imaging as necessary. RESULTS: Neither significant complications nor technical failures were observed. A complete resolution of the abscess was achieved in 14 patients, and significant resolution of abscess was also observed in the other 2 patients. CONCLUSIONS: Sonography and fluoroscopic guided percutaneous paracoccygeal drainage is safe, feasible and efficient approach in the treatment of deep pelvic abscess.

Antegrade recanalization of parent artery in internal trapping of vertebral artery dissecting aneurysm: a case report.

BACKGROUND: We describe a case involving technical success with internal trapping using controllable detachable coils yet antegrade recanalization of the occluded vertebral artery, in the vertebral artery dissecting aneurysm. Possible explanations for the antegrade recanalization of the occluded vertebral artery and lessons from the case are also discussed. CASE DESCRIPTION: A 42-year-old woman with a history of stupor (Hunt and Hess grade III) and right vertebral artery dissecting aneurysm, was admitted to our hospital. Endovascular treatment was performed. The dissecting aneurysm and affected right vertebral artery were both completely occluded, whereas the right PICA was preserved. Nine months after the embolization, follow-up angiography was performed, which revealed recanalization of the occluded right vertebral artery with a normal arterial configuration and antegrade flow into the basilar artery. The recanalized vertebral artery was located just superior and lateral to the deployed coil meshes. It was decided that no further intervention was needed. At the last clinical follow-up 15 months after the initial treatment, the patient was fully recovered. CONCLUSION: Even in the case of technical angiographic success in the endovascular management of a dissecting aneurysm, a prompt follow-up angiography is still crucial. Plus, if the false lumen cannot be separated from the true lumen, treatment with just a stent may not be adequate.

Biliary atresia: feasibility of mangafodipir trisodium-enhanced MR cholangiography for evaluation.

The study was approved by the institutional review board, and informed consent was obtained from the patients' parents. Twenty-three consecutive infants suspected of having biliary atresia (BA) were prospectively examined by using mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) cholangiography. Sequential T1-weighted spoiled gradient-echo MR cholangiograms were obtained 1, 2, and 3 hours after intravenous administration of Mn-DPDP. The possibility of BA was excluded if bowel excretion of contrast material was noted at contrast material-enhanced MR cholangiography. The diagnostic specificity and accuracy of contrast-enhanced MR cholangiography were compared with those of conventional MR cholangiography, technetium 99m Tc ((99m)Tc)-disofenin (DISIDA) scintigraphy, and the triangular cord sign at ultrasonography (US). MR cholangiography was used to accurately distinguish four cases of BA from 19 cases of other cholestatic liver diseases, without false-positive results. Conventional MR cholangiography, (99m)Tc-DISIDA scintigraphy, and the triangular cord sign at US respectively yielded false-positive results of 42% (eight of 19 infants), 35% (six of 17 infants), and 11% (two of 19 infants) in patients without BA. Mn-DPDP-enhanced MR cholangiography appears to be a promising modality for early diagnosis of BA as the cause of neonatal cholestasis.

Auditory neural pathway evaluation on sensorineural hearing loss using diffusion tensor imaging.

Diffusion tensor imaging is a new in vivo tool not only for the assessment of white matter structural integrity but also for diagnosis and assessment of disease conditions which disturb tissue structural coherence. In this study, we investigated the integrity of auditory pathway in patients of sensorineural hearing loss by means of fractional anisotropy of water diffusion to see any subtle changes of auditory pathways resulting from sensorineural hearing loss. In addition, this study suggests that the diffusion anisotropy measured by diffusion tensor imaging is highly sensitive to otherwise subtle disease processes not normally seen with conventional magnetic resonance imaging or computed tomography contrast.

Quantitative evaluation of liver function with MRI Using Gd-EOB-DTPA.

OBJECTIVE: Gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a newly developed MR contrast agent. After intravenous injection, Gd-EOB-DTPA is gradually taken up by the hepatocytes and eventually excreted via the biliary pathway without any change to its chemical structure. Because of these characteristics, it can be used as a tracer for quantitative liver function testing. The purpose of this study is to develop a noninvasive method of quantitation of the hepatic function using Gd-EOB-DTPA through the deconvolution analysis. MATERIALS AND METHODS: Adult New Zealand white rabbits (n = 10, average body weight = 3.5 kg) were used in the present study. Hepatic injury was induced to by the intragastric administration of carbon tetrachloride (CCl4) three times a week for three weeks. Liver enzyme (aspartate aminotransferase, AST; alanine aminotransferase, ALT) levels and the plasma indocyanine green (ICG) retention rate 15 minutes after an intravenous injection of ICG (ICG R15), was checked before and after the three-week administration of CCl4. At the end of experimental period, an observer "blinded" to the treatment given the rabbits performed the histological examination. MRI studies were performed before and after the three-week administration of CCl4 on a 1.5 T scanner using a human extremity coil. After intravenous bolus injection of Gd-EOB-DTPA (0.3 mL of Gd-EOB-DTPA freshly prepared in 2.7 mL of normal saline) through the ear vein, the 250 axial single level dynamic MR images were obtained using a fast low angle shot (FLASH, T /TE = 11/4.2 msec, flip angle = 15, acquisition time 1 second, slice thickness = 5 mm, matrix = 128x128, field of view = 120 mm) sequence with 1.5 sec time intervals. The time-intensity curves were obtained at the abdominal aorta and the liver parenchyma that was devoid of blood vessels. Deconvolution analysis of the aortic (input function) and hepatic parenchymal (output function) time-intensity curves was performed with a modified Fourier transform technique to calculate the hepatic extraction fraction (HEF). The presence and type of hepatic injury were determined by the histopathologic examination and statistical analysis of the changes of the hepatic enzyme levels, the ICG R15 and Gd-EOBDTPA HEF values between the time before and after CCl4 administration with Wicoxon signed rank test. Correlation between the Gd-EOB-DTPA HEF and the change of the ICG R15 were analyzed with Pearson's correlation coefficient. RESULTS: Histopathologic examination showed findings that were compatible with hepatic fibrosis caused by chronic liver injury. The initial blood biochemical studies before the administration of carbon tetrachloride showed that the mean AST and ALT levels were 39.8+/-5.2 IU/L and 59.1+/-11.7 IU/L, respectively. The AST and ALT levels increased to 138.4+/-50.5 IU and 172.0+/-71.6 IU/L, respectively, after the three week administration of CCl4. The ALT and AST levels were significantly increased after the three weeks of CCl4 administration (p = 0.018). The ICG R15 values were 4.47+/-2.08% and 19.43+/-3.98% before and after three-week administration of CCl4, respectively. The ICG R15 values were significantly increased after hepatic injury (p = 0.018). After normalizing the HEF as 100% in each rabbit before CCl4 administration, the deconvoluted curve after CCl4 administration revealed less hepatocyte extraction efficiency with a mean value of 77.7+/-3.6. There was a significant correlation between the HEF and changes of the ICG R15 by the Pearson correlation coefficient assessment (correlation coefficient = -0.965, p = 0.000). CONCLUSION: The Gd-EOB-DTPA HEF could be calculated from deconvolution analysis of aortic and hepatic parenchymal time-intensity curves obtained by dynamic MRI. The Gd-EOB-DTPA HEF was well correlated with changes of the ICG R15, which is the most common parameter used in the quantitative estimation of the hepatic function. The Gd-EOB-DTPA HEF is a direct, noninvasive technique for the quantitative evaluation of liver function. It could be a promising alternative for the determination of noninvasive hepatic function in those patients with liver disease.

Functional magnetic resonance image finding of cortical activation by neuromuscular electrical stimulation on wrist extensor muscles.

OBJECTIVE: To investigate the effects that neuromuscular electrical stimulation on the wrist extensor muscles have on the cerebral cortex. DESIGN: A functional magnetic resonance imaging study was performed on eight normal volunteers. The activation task was the maximum wrist extension by neuromuscular electrical stimulation, applied through a two-channel electrical stimulator. Monophasic square-wave pulses were used. The activation maps were generated by the threshold test maps. The level of primary motor cortex and primary sensory cortex activations was estimated. RESULTS: Among the eight subjects, seven showed significant activation on contralateral primary sensorimotor cortex by neuromuscular electrical stimulation on the wrist extensor muscles. In these seven subjects, additional bilateral or contralateral supplementary motor area activations were also observed. The number of activated pixels on the primary sensory cortex was slightly greater than that on the primary motor cortex. CONCLUSION: Neuromuscular electrical stimulation, when applied to the peripheral muscles, seems to have a direct effect on the cerebral cortex.