摘要:

AbstractTo better understand the use of magnetic resonance angiography (MRA) in evaluating peripheral vascular disease, the authors studied arteries in the foot and ankle. Twenty patients with arterial occlusive disease of the lower extremity were studied with two‐dimensional time‐of‐flight MRA, and the results were compared with those of 10 conventional x‐ray arteriograms, four digital subtraction arteriograms, and three intraoperative arteriograms. The studies were reviewed and rated by three radiologists blinded to the patients' clinical history. Also, the first 16 patients were examined with MRA before and after intravenous injection of gadopentetate dimeglumine. The mean confidence levels for the reviewers' interpretations of the MRA studies were significantly higher than those for the conventional arteriograms for the medial plantar, lateral plantar, and plantar arch arteries of the feet (P≦ 0.005).Postcontrast MRA images were inferior to precontrast images because of overlapping of veins and arteries. Time‐of‐flight MRA without gadolinium can serve as a useful complementary study for evaluating patients with peripheral vascular disease in the f

ISSN:1053-1807    

DOI:10.1002/jmri.1880050102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880050103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe purpose of the study was to determine if derivatization of cholesterol with a paramagnetic label could result in an organ‐specific contrast agent for magnetic resonance imaging of the adrenal glands. Gadolinium‐DO3A‐labeled cholesterol was synthesized and the relaxivities in water and blood plasma determined at 0.47 T and 40°C. Organ distribution was measured at 2 (n= 2) and 24 (n= 2) hours after intravenous injection of a 50 μmol/kg dose of Gd‐DO3A‐cholesterol in rats weighing 220–240 g. T1‐weighted spin‐echo images were acquired at 2 T before and after injection of 50 μmol/kg Gd‐DO3A‐cholesterol (n= 2) and Gd‐DTPA (diethylenetriaminepentaacetic acid)‐albumin (n= 2). More than 99% of the Gd‐DO3A‐cholesterol was found to be protein bound in bovine serum. High T1 and T2 relaxivities were found in water and plasma. High tissue concentrations of Gd‐DO3A‐cholesterol were found only in adrenal glands and liver. At 24 hours, adrenal gadolinium concentrations were about 10 times higher than in blood. At 2 hours after injection of Gd‐DO3A‐cholesterol. enhancement was 162% in adrenal glands and 146% in liver. With Gd‐DTPA‐albumin, enhance

ISSN:1053-1807    

DOI:10.1002/jmri.1880050104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractManganese (II)N,N'‐dipyridoxylethylenediamine‐N,N'‐diacetate 5,5′‐bis(phosphate) (DPDP) is a paramagnetic magnetic resonance (MR) contrast agent that enhances the liver and is predominantly excreted through the biliary tree. The authors evaluated its utility in diffuse liver disease by assessing liver and gallbladder enhancement in 24 rabbits. Total (n= 6) or segmental (n= 6) biliary occlusion or galactosamine‐induced hepatitis (n= 6) was induced 3 days before imaging. Six rabbits served as normal controls. T1‐ and T2‐weighted axial MR images were acquired at baseline, followed by T1‐weighted images every 10 minutes for 1 hour after the intravenous administration of 20 μmol/kg Mn‐DPDP. Except for the segmental occlusion group, the baseline study did not allow distinction between normal and abnormal livers. The temporal hepatic enhancement pattern was statistically different for each group. The normal, segmental occlusion, and hepatitis groups showed patterns similar to one another but markedly higher signal intensity than the total‐occlusion group throughout the observation period. In contrast, the gallbladder showed a greater difference in both degree of enhancement and time to peak enhancement among the four groups. Mn‐DPDP produces a temporal hepatic enhancement pattern that allows recognition of markedly impaired livers, and gallbladder enhancement patterns that allow distinction of mor

ISSN:1053-1807    

DOI:10.1002/jmri.1880050105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAs part of the clinical evaluation of gadoteridol injection, intravenous doses ranging from 0.05 to 0.3 mmol/kg were administered to 1,709 patients and volunteers. Safety monitoring included pre‐ and postdose physical examinations, vital signs, and clinical laboratory values. Adverse event recording included occurrence, duration, severity, relationship to injection, and clinical importance. No clinically important changes in physical examination results, electrocardiograms, or vital signs were attributed to gadoteridol injection except for one case of hypotension. Four clinically important changes in laboratory values possibly or definitely related to the contrast agent were noted in two patients (0.1%). Adverse events were recorded in 118 subjects (6.9%), including nausea in 24 subjects (1.4%) and taste perversion in 22 subjects (1.3%). All other adverse events occurred with a frequency of less than 1%. Adverse events related to contrast agent administration occurred in 79 subjects (4.6%). Gadoteridol injection demonstrated excellent clinical safety and patient tolerance at various doses and injection rate

ISSN:1053-1807    

DOI:10.1002/jmri.1880050106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880050107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractTo identify changes induced by chemotherapy in hepatic metastases, 34 patients with metastases underwent magnetic resonance (MR) imaging before the start of systemic chemotherapy and monthly thereafter. The number, size, and morphologic patterns of the lesions and changes in quantitative parameters (signal‐to‐noise ratio [S/N], contrast‐to‐noise ratio, and signal intensity ratio) were evaluated and correlated with response to treatment and prognosis. After treatment, seven patients showed a partial response, 18 had stable disease, and nine had progressive disease. No relevant changes in the patterns of the lesions were observed. Quantitative data showed that patients with a good prognosis had an increase in S/N on T1‐weighted images and a relative decrease on T2‐weighted images; patients with a poor prognosis showed a decrease in S/N on T1‐weighted images and an increase on T2‐weighted images. The differences between patient groups were significant for both T1‐ and T2‐ weighted images. This study demonstrates the value of MR imaging in follow‐up of liver metastases and suggests the usefulness of quantit

ISSN:1053-1807    

DOI:10.1002/jmri.1880050108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAlmost all methods of measuring residual volume of urine in the bladder of patients undergoing urologic assessment are biased to an unknown extent. The authors describe the application of an unbiased stereologic technique for estimating the volume of bladder urine known as the Cavalieri method. The method requires imaging of a series of systematic (ie, equally spaced) parallel sections through the bladder. Such data can be conveniently obtained with magnetic resonance (MR) imaging. If sampling begins at a position randomly chosen within the distance corresponding to the section interval. bladder volume is estimated without bias as the sum of the areas of the bladder sections on the images multiplied by the section interval. Computer‐aided point‐counting techniques represent an efficient means of obtaining the required section area estimates. Optimum sectioning and point counting densities for estimating bladder volume were established by analyzing detailed data sets obtained in five volunteers. It was shown that if an average of only 20 points were counted in each of only five systematic sections through the bladder, the volume of bladder urine was estimated with a coefficient of error of about 5%. By studying these five volunteers and an additional 13 with MR imaging and the Cavalieri method, the authors showed that the difference between the volume of urine in the bladder before and after micturition is unbiased (ie, shows no systematic difference) with respect to the volume of urine voided by the subje

ISSN:1053-1807    

DOI:10.1002/jmri.1880050109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880050110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractTo determine whether there were age‐related changes In the brain tissue of 55 healthy adult volunteers (29 men, 26 women; 18‐72 years old) without known brain abnormalities, a standard inversion‐recovery technique was optimized for precise and accurate T1 measurement within the constraints of a 15‐minute examination. Measurements of water proton T1 were obtained in eight brain regions. T1 increased with age in the genu (P<0.001) (analysis of variance), frontal white matter (P<0.05), occipital white matter (P<0.05), putamen (P<0.001), and thalamus (P<<0.001). A significant decrease in T1 with age was found in cortical gray matter (P<0.05). Thus, age‐related changes in T1 are present in a healthy population, even if extremes of age are excluded, suggesting that T1 values generally increase with age. However, increases in T1 were also observed in the genu, putamen, and thalamus of a substantial fraction of volunteers less than 35 years old. Aging healthy persons can show subtle, nonsymp‐ tomatic brain changes, suggesting that brain aging is associated with occult processes that can begin at a relativel

ISSN:1053-1807    

DOI:10.1002/jmri.1880050111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY