The purpose of this study was to evaluate the feasibility and safety of using gadolinium-chelates for digital subtraction angiography (DSA) in patients with contraindications to iodinated contrast material, and to assess the clinically effective concentration of gadolinium (Gd). Gadopentetate dimeglumine and iopromide were used in density measurements. Using 20 mL disposable syringes, serial dilutions of Gd and iopromide with saline were performed. Computed tomography scanning was done and the attenuation of each was recorded as mean Hounsfield units using region of interest analysis. Clinical trials were done in twelve patients with the following types of angiogram or intervention: hemodialysis access, percutaneous biliary drainage, percutaneous nephrostomy, cerebral angiography and transarterial chemoembolization (TACE) in hepatocellular carcinoma. The density of 1 : 1 diluted Gd was nearly equal to that of 1 : 4 dilution of iopromide, and that of pure Gd was similar to or less than that of 1 : 1 dilution of iopromide. Serum creatinine level was not elevated in any of the patients. Gd is a safe alternative agent in patients with contraindications to iodinated contrast materials. Pure Gd without dilution is the most clinically useful concentration.
Angiography, Digital Subtraction/*methods ; *Contrast Media/adverse effects ; Feasibility Studies ; Gadolinium DTPA/adverse effects/*diagnostic use ; Human ; Safety

The purpose of this study was to compare the image quality of 3D-TOF MR angiography (MRA) using Gadomer-17 with that using Gd-DTPA in a flow phantom model, and to present preliminary data about the proper dose concentration of Gadomer-17. In the visual analysis of vessel conspicuity, we compared the quality of pre- and post-contrast MIP images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and then the relative contrast enhancement was calculated. The results of our studies were that: 1. Maximal signal intensities were obtained at 1 mmol/L of Gadomer-17 and 4 mmol/L of Gd-DTPA. 2. Flow-related signal loss was decreased by Gd-DTPA proportional to the concentration, but Gadomer-17 did not show such a dose accumulative effect. In conclusion, after comparing the results of Gd-DTPA, it was clear that improved MRA images and higher signal intensities of vessels were obtained when lower concentrations of Gadomer-17 were used.
Comparative Study ; Contrast Media*/administration & dosage ; Dose-Response Relationship, Drug ; Gadolinium DTPA/diagnostic use* ; Human ; Magnetic Resonance Angiography*

OBJECTIVE: To determine whether the size of a perfusion defect seen at myocardial perfusion MR imaging represents the extent of irreversibly damaged myocardium in acute reperfused myocardial infarction. MATERIALS AND METHODS: In nine cats, reperfused myocardial infarction was induced by occlusion of the left anterior descending coronary artery for 90 minutes and subsequent reperfusion for 90 minutes. At single-slice myocardial perfusion MR imaging at the midventricular level using a turbo-FLASH sequence, 60 short-axis images were sequentially obtained with every heart beat after bolus injection of gadomer-17. The size of the perfusion defect was measured and compared with both the corresponding unstained area seen at triphenyl tetrazolium chloride (TTC) staining and the hyperenhanced area seen at gadophrin-2-enhanced MR imaging performed in the same cat six hours after myocardial perfusion MR imaging. RESULTS: The sizes of perfusion defects seen at gadomer-17-enhanced perfusion MR imaging, unstained areas at TTC staining, and hyperenhanced areas at gadophrin-2-enhanced MR imaging were 20.4+/-4.3%, 29.0+/-9.7%, and 30.7+/-10.6% of the left ventricular myocardium, respectively. The perfusion defects seen at myocardial perfusion MR imaging were significantly smaller than the unstained areas at TTC staining and hyperenhanced areas at gadophrin-2-enhanced MR imaging (p < .01). The sizes of both the perfusion defect at myocardial perfusion MR imaging and the hyperenhanced area at gadophrin-2- enhanced MR imaging correlated well with the sizes of unstained areas at TTC staining (r = .64, p = .062 and r = .70, p = .035, respectively). CONCLUSION: In this cat model, the perfusion defect revealed by myocardial perfusion MR imaging underestimated the true size of acute reperfused myocardial infarction. The defect may represent a more severely damaged area of infarction and probably has prognostic significance.
Animal ; Cats ; Contrast Media ; Gadolinium ; Gadolinium DTPA/diagnostic use ; *Magnetic Resonance Imaging ; Mesoporphyrins/diagnostic use ; Metalloporphyrins/diagnostic use ; Myocardial Infarction/*pathology/therapy ; *Myocardial Reperfusion ; Myocardium/pathology ; Support, Non-U.S. Gov't

Prostatic stromal sarcoma (PSS) is quite rare. Herein, we describe magnetic resonance imaging (MRI) features of a PSS identified in a 26-year-old man with dysuria and hematuria. MRI clearly depicted the extent and multinodular appearance of the tumor, which was mainly located in the central zone of the prostate. The tumor appeared as a heterogeneously signal-hyperintense mass with a pseudocapsule on T2-weighted imaging. Contrast-enhanced T1-weighted MRI showed necrotic portions in the gradually enhanced solid mass, and diffusion-weighted imaging permitted the accurate assessment of the local extent of the tumor. Thus, the appearance on MRI was quite different from that of adenocarcinoma of the prostate.
Adult ; Contrast Media/diagnostic use ; Diagnosis, Differential ; Fatal Outcome ; Gadolinium DTPA/diagnostic use ; Humans ; Magnetic Resonance Imaging/*methods ; Male ; Prostatic Neoplasms/*diagnosis ; Stromal Cells/*pathology

OBJECTIVE: To evaluate the temporal evolution and diagnostic values of the diffusion tensor imaging (DTI) and the high b value diffusion weighted imaging (DWI) in the early permanent and transient cerebral ischemia. MATERIALS AND METHODS: For permanent or 30-minute transient-ischemia induced 30 rats, DTI and DWIs at both high b (b = 3000 s/mm2) and standard b value (b = 1000 s/mm2) were obtained at the following conditions: at 15, 30, 45, 60 minutes after the occlusion of what for hyperacute permanent ischemia; at 1, 3, 5, 7, 9 hours after the occlusion for acute permanent ischemia; and at 15 minutes before reperfusion, 0.5, 2.5, and 24 hours after reperfusion for transient ischemia. The diffusion parameters and their ratios were obtained and compared between different b values, and among different time points and groups, respectively. RESULTS: For both b values, the apparent diffusion coefficient (ADC) ratio decreased for first three hours, and then slightly increased until 9 hours after the occlusion during a gradual continuous increase of DWI signal intensity (SI) ratio, with excellent correlation between ADC ratios and DWI SI ratios. The DWI showed a higher contrast ratio, but the ADC map showed a lower contrast ratio for permanent ischemia at high b value than at standard b value. Fractional anisotropy (FA) increased for 1 hour, then gradually decreased until 9 hours after the occlusion in permanent ischemia and showed transient normalization and secondary decay along with change in ADC in transient ischemia. CONCLUSION: This study presents characteristic initial elevation and secondary decay of FA, higher contrast ratio of DWI, and lower contrast ratio of ADC map at high b value, in addition to the time evolutions of diffusion parameters in early permanent and transient ischemia.
Animals ; Contrast Media/diagnostic use ; Diffusion Magnetic Resonance Imaging/*methods ; Gadolinium DTPA/diagnostic use ; Ischemic Attack, Transient/*diagnosis ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the relationships between the apparent diffusion coefficients (ADCs) on diffusion-weighted imaging (DWI) and the speed of contrast-enhancement in hepatic hemangiomas. MATERIALS AND METHODS: Sixty-nine hepatic hemangiomas (> or = 1 cm) were evaluated with DWI, by using multiple b values (b = 50, 400, 800 s/mm2), followed by a gadolinium-enhanced dynamic MRI. The lesions were classified into three groups, according to the speed of contrast-enhancement on the portal phase. ADCs were measured on the ADC map automatically, and were calculated by using the two different b values (mADC50-400 with b values = 50 and 400; mADC400-800 with b values = 400 and 800 s/mm2). RESULTS: The mean ADCs (x 10-3 mm2/s) were significantly higher in the rapid group (1.9 +/- 0.44) than in the intermediate (1.7 +/- 0.35, p = 0.046) or the slow groups (1.4 +/- 0.34, p = 0.002). There were significant differences between the rapid and the slow groups in mADC50-400 (2.12 vs. 1.48; p = 0.008) and mADC400-800 (1.68 vs. 1.22, p = 0.010), and between the rapid and the intermediate groups in mADC50-400 (2.12 vs. 1.79, p = 0.049). Comparing mADC50-400 with mADC400-800, there was a significant difference only in the rapid group (p = 0.001). CONCLUSION: Higher ADCs of rapidly-enhancing hemangiomas may be related to richer intralesional vascular perfusion. Also, the restricted diffusion may be attributed to the difference of structural characteristics of hemangioma.
Adult ; Aged ; Contrast Media ; *Diffusion Magnetic Resonance Imaging ; Female ; Gadolinium DTPA/diagnostic use ; Hemangioma, Cavernous/*diagnosis ; Humans ; Image Enhancement ; Liver Neoplasms/*diagnosis ; *Magnetic Resonance Imaging ; Male ; Middle Aged

OBJECTIVE: To determine the optimal scan timing for contrast-enhanced magnetic resonance angiography and to evaluate a new timing method based on the arteriovenous circulation time. MATERIALS AND METHODS: Eighty-nine contrast-enhanced magnetic resonance angiographic examinations were performed mainly in the extremities. A 1.5T scanner with a 3-D turbo-FLASH sequence was used, and during each study, two consecutive arterial phases and one venous phase were acquired. Scan delay time was calculated from the time-intensity curve by the traditional (n = 48) and/or the new (n = 41) method. This latter was based on arteriovenous circulation time rather than peak arterial enhancement time, as used in the traditional method. The numbers of first-phase images showing a properly enhanced arterial phase were compared between the two methods. RESULTS: Mean scan delay time was 5.4 sec longer with the new method than with the traditional. Properly enhanced first-phase images were found in 65% of cases (31/48) using the traditional timing method, and 95% (39/41) using the new method. When cases in which there was mismatch between the target vessel and the time-intensity curve acquisition site are excluded, erroneous acquisition occurred in seven cases with the traditional method, but in none with the new method. CONCLUSION: The calculation of scan delay time on the basis of arteriovenous circulation time provides better timing for arterial phase acquisition than the traditional method.
*Contrast Media ; Female ; Gadolinium DTPA/*diagnostic use ; Human ; Image Processing, Computer-Assisted ; Injections, Intravenous ; Magnetic Resonance Angiography/*methods ; Male ; Middle Age ; Time Factors

OBJECTIVE: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. MATERIALS AND METHODS: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calcu-lated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. RESULTS: Mean rCBV ratios were 4.90'+/-1.01 for glioblastomas, 3.97'+/-0.56 for anaplastic gliomas and 1.75'+/-1.51 for low-grade gliomas, and were thus sig-nificantly different; p < .05 between glioblastomas and anaplastic gliomas, p <.05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblas-tomas and low-grade gliomas. The rCBV ratio cutoff value which permitted dis-crimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. CONCLUSION: Perfusion MR imaging is a useful and reliable technique for esti-mating the histologic grade of gliomas.
Adult ; Astrocytoma/*pathology ; Brain/pathology ; Brain Neoplasms/*pathology ; Cerebrovascular Circulation ; Contrast Media ; Female ; Gadolinium DTPA/diagnostic use ; Glioblastoma/*pathology ; Human ; *Magnetic Resonance Imaging ; Male ; Support, Non-U.S. Gov't

We report an uncommon case of solitary, small hepatic angiosarcoma that was initially considered as a hemangioma. We present the imaging findings, with an emphasis on the initial and follow-up CT and MR findings, as well as report on the more suggestive findings of angiosarcoma than those of a hemangioma.
Contrast Media ; Diagnosis, Differential ; Gadolinium DTPA/diagnostic use ; Hemangioma/diagnosis ; Hemangiosarcoma/*diagnosis/surgery ; Humans ; Liver Neoplasms/*diagnosis/surgery ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Tomography, X-Ray Computed

OBJECTIVE: To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. MATERIALS AND METHODS: In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose time-intensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parame-ters used were arterial and venous enhancement times, arterial peak enhance-ment time, arteriovenous circulation time, enhancement duration and enhance-ment expansion ratio. RESULTS: Between the main and test boluses, arterial and venous enhance-ment times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. CONCLUSION: Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.
Adult ; Aorta, Abdominal/anatomy & histology ; Contrast Media/*administration & dosage ; Female ; Gadolinium DTPA/*administration & dosage/diagnostic use ; Human ; Magnetic Resonance Angiography/*methods ; Male ; Time Factors