Enhancement of hepatic hemangiomas with levovist on coded harmonic angiographic ultrasonography.

OBJECTIVE: To evaluate the pattern of contrast enhancement with Levovist on coded harmonic angiographic ultrasonography of hepatic hemangiomas. METHODS: Twenty hemangiomas were evaluated with coded harmonic angiographic ultrasonography and a microbubble contrast agent. Verification of the diagnosis of a hemangioma was made by means of dynamic computed tomography (n = 8), dynamic magnetic resonance imaging (n = 1), radionuclide scanning (n = 6), or follow-up ultrasonography (n = 5). Ultrasonographic images were obtained before contrast agent administration and with a bolus injection of 2.5 g of a microbubble contrast agent (300 mg/mL Levovist; Schering AG, Berlin, Germany) every 10 to 15 seconds for 5 minutes. The contrast enhancement patterns of the 20 hemangiomas were assessed. RESULTS: The tumor diameters as measured on ultrasonography were 7 to 97 mm (mean, 26.7 mm). Of the 20 hemangiomas, peripheral globular enhancement with progressive centripetal fill-in was shown in 15 (75%), rimlike enhancement with progressive centripetal fill-in was shown in 2 (10%), and homogeneous enhancement was shown in 1 (5%). In the remaining 2 lesions (10%), the enhancement patterns could not be seen, because they were not found on coded harmonic angiographic ultrasonography. CONCLUSIONS: Coded harmonic angiographic ultrasonography with a microbubble contrast agent can depict the typical enhancement pattern in most hepatic hemangiomas.     

消旋17-苯-18,19,20-失三碳前列腺素F2α甲酯及其15-差向异构体的合成

从中间体(4)出发,经醛(5),与鏻叶立德(3)或2-酮-4-苯丁烷磷酸酯(11)钠缩合成(6),再钠硼氢还原得3′α-醇(7A)及其差向异构体(7B),经硅胶柱色谱分开,分别经二异丁基铝氢还原,与溴化5-三苯鏻戊酸之Wittig试剂缩合,得17-苯-18,19,20-失三碳前列腺素F_2α(9A)及其15-差向异构体(9B),再用重氮甲烷甲酯化,分别得相应的17-苯-18,19,20-失三碳前列腺素F_2α甲酯(10A)及其15-差向异构体(10B)。     

Efficacy evaluation of gadoteridol for MR angiography of intracranial vascular lesions

A phase III multicenter study was conducted in 89 patients with known intracranial vascular lesions to evaluate an extracellular gadolinium contrast agent, gadoteridol, for intracranial magnetic resonance (MR) angiography. The pre- and postcontrast MR angiograms of 82 patients were evaluated by the unblinded investigators and by two blinded readers (A and B) for visualization of lesions; arterial and venous anatomy; extent, size, and number of lesions; and disease classification. The unblinded readers indicated that lesions were visualized better on postcontrast images in the following categories: venous anatomy, 87 (81%) of 107 lesions; arterial anatomy, 43 lesions (40%); and extent or size of lesions, 38 lesions (36%). In 29 (35%) of 82 patients, the unblinded readers determined that enhanced MR angiography provided more diagnostic information than unenhanced MR angiography. The blinded readers determined that enhanced MR angiography provided more information for visualization of vascular anatomy in more than 60% of cases. The additional information provided with gadoteridol would have changed the diagnosis in nine (8%) of 107 lesions seen by the unblinded readers, 11 (12%) of 90 lesions seen by reader A, and three (3%) of 93 lesions seen by reader B. The results confirm that the use of gadoteridol improves the visualization of intracranial vascular lesions with MR angiography. The authors conclude that development of new postprocessing algorithms will improve the utility of contrast-enhanced MR angiography.     

Dynamic gadolinium-enhanced MRI in the detection of spinal arteriovenous malformations

Arteriovenous fistulae and malformations (AVFs and AVMs) of the spinal cord are rare, potentially treatable causes of progressive disability. Although a variety of MRI abnormalities has been described, the diagnosis rests on the findings on selective spinal angiography.Collecting T2^*-weighted MR images during the passage of a gadolinium bolus gives information about perfusion and blood volume. We carried out dynamic MRI in seven patients with vascular abnormalities (5 dural AVFs, 1 intramedullary AVM, 1 cryptic angioma) and in two patients without an AVM. High resolution T1- and T2-weighted sagittal images of the whole spinal cord were first obtained using a multiarray receiver coil. Sagittal radiofrequency spoilt gradient echo images (GE34/25, flip angle 10⁰) were then obtained during bolus injection of gadolinium-DTPA. Abnormalities were seen in all seven patients with AVFs or AVMs. In the patient with an intramedullary AVM and four of the five with dural AVFs transient signal reduction was seen within the perimedullary venous plexus during passage of the bolus. The findings correlated well with those from selective spinal angiography. We conclude that dynamic MRI offers a useful adjunct to angiography and may localise an arteriovenous shunt when conventional MRI fails to do so. In combination with high-resolution imaging of the entire spinal cord the technique may make myelography redundant; it is simple, well tolerated and can be carried out without significant time penalty.     

Vessel enhancement filtering in three-dimensional MR angiograms using long-range signal correlation

Small vessels in three-dimensional MR angiograms have low visibility in maximum-intensity projection images because of their low contrast. In a previous study, we had two nonlinear filters that appeared to give significant improvement in small vessel detail. In this paper, we report on a generalization of this filter that allows a more general modeling of the vessels and a more complete suppression of background. One implementation of the general filter gave a vessel mean contrast-to-noise ratio that is 2.52 and 3.51 times higher than the vessel mean contrast-to-noise ratio obtained using our previously reported maximum-minimum (max-min) filter and cross- section filter, respectively.     

Effect on fetal mouse development of exposure to MR imaging and gadopentetate dimeglumine

Pregnant mice were exposed to one of five regimens at 9.5 days of gestation: no treatment (group 1), intraperitoneal injection of normal saline (group 2), intraperitoneal injection of gadopentetate dimeglumine (group 3), intraperitoneal injection of gadopentetate dimeglumine and magnetic resonance (MR) exposure (group 4), and MR exposure alone (group 5). At 18 days of gestation, the mice were sacrifice and fetuses were removed and examined for the following end points: litter size, number alive or dead, fetal weight, extremity morphology, eye and ear development, and appearance of the head. A total of 739 fetuses were analyzed: group 1 (n = 161), group 2 (n = 149), group 3 (n = 142), group 4 (n = 136), and group 5 (n = 151). The only statistically significant difference was a lower mean fetal weight in the saline-injection group compared with the control group. The results show that MR exposure with and without gadopentetate dimeglumine had no adverse effect on the end points analyzed.     

Closed-Chest Cardiopulmonary Bypass and Cardioplegia: Basis for Less Invasive Cardiac Surgery

Background. We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed.

Methods. Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter.

Results. Cardiopulmonary bypass time was 111 ± 27 minutes (mean ± standard deviation) and cardiac arrest time was 66 ± 21 minutes. Preoperative cardiac outputs were 2.9 ± 0.70 L/min and postoperative outputs were 2.9 ± 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially.

Conclusions. Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.     

Synthesis and cytotoxic activity of new alkyl[3-(2-chloroethyl)ureido]benzene derivatives

Several alkyl[3-(2-chloroethyl)ureido] (CEU) benzene derivatives were prepared as potential anticancer agents. These new compounds were readily prepared in good yields by addition of anilines to 2-chloroethylisocyanate. Their cytotoxic activity was evaluated on human breast cancer (MDA-MB-231), human colon adenocarcinoma (LoVo) and mouse lymphocytic leukemia (P388D₁) tumor cell lines. Several new CEUs were significantly more cytotoxic than the nitrogen mustard chlorambucil. The biological activity of these aromatic urea derivatives seems to be related to the nature and position of the alkyl substituents on the aromatic ring. Substitution by branched alkyl groups on position 4 of the aromatic ring led to cytotoxic molecules which are up to 5 times more potent than the standard chlorambucil.     

Gd-DTPA-cascade-polymer: Potential blood pool contrast agent for MR imaging

Gadolinium-DTPA (diethylenetriaminepentaacetic acid)-cascade-polymer, a potential new blood pool contrast agent for magnetic resonance (MR) imaging, was compared with a known blood pool agent, Gd-DTPA-polylysine, in an animal model. The relative signal intensities of liver, renal cortex, pancreas, and trunk muscle were assessed in 12 pigs between 4 seconds and 120 minutes after injection of a 20 μmol/kg dose of each contrast agent, by using a FLASH (fast low-angle shot) sequence. Except for muscle, all tissues showed visible enhancement after injection of either contrast agent. After injection of Gd-DTPA-polymer, enhancement patterns in the liver, renal cortex, and pancreas were similar to those seen after injection of Gd-DTPA-polylysine. No statistically significant differences in enhancement between the two contrast agents were found at any time point. The authors conclude that the contrast kinetics of Gd-DTPA-cascade-polymer are similar to those of Gd-DTPA-polylysine and that this agent may also be used as a blood pool contrast agent for MR imaging.