It has been reported that cavernous hemangiomas in the spine are generally located in vertebral bodies. Wereport a case of epidural cavernous hemangioma, a very rare condition, at the C7-T2 level. MR images showed adumbbell-shaped mass, with iso and high signal intensity on T1- and T2-weighted images, respectively. The mass wasintensely enhanced following Gd-DTPA injection.
Gadolinium DTPA ; Hemangioma, Cavernous* ; Spine

PURPOSE: To evaluate the NMR relaxation properties and imaging characteristics of tissue-specificity for a newly developed macromolecular MR agent. MATERIALS AND METHODS: Phthalocyanine (PC) was chelated with paramagnetic ion, Mn. 2.01g(5.2 mmol) of Phthalocyanine was mixed with 0.37g (1.4 mmol) of Mn chloride at 310 degrees C for 36 hours and then purified by chromatography (CHC13/CH3OH 98/2 v/v, Rf, 0.76) to obtain 1.04g (46%) of MnPC (molecular weight = 2000d), The T1/T2 relaxivity of MnPC was measured in 1.5T(64 MHz) MR using 0.1 mM MnPC. The MR image characteristics of MnPC was evaluated using spin-echo (TR/TE = 500/14 msec) and gradient-echo (FLASH) (TR/TE = 80/4 msec, flip angle = 60) techniques in 1.5T MR scanner. The images of rabbit liver were obtained every 10 minutes up to 4 hours. To study the effect of concentration on image, 20 mM, 50 mM, 100 mM of MnPC were tested. RESULTS: The relaxivities of MnPC at 1.5T (64MHz) were R1 = 7.28 mM-1S-1, R2 = 55.56 mM-1S-1. Compared to the values of Gd-DTPA (R1[= 4.8 mM-1S-1), R2[= 5.2 mM-1S-1]), both T1/T2 relaxivities of MnPC were higher than those of Gd-DTPA. For both of SE and FLASH techniques, the contrast enhancement reached maximum at 10 minutes after bolus injection and the enhancement continued for more than 2 hours. When compared with small molecular weight liver agents such as Gd-EOB-DTPA, Gd-BOPTA and MnDPDP, MnPC was characterized by more prolonged enhancement time. The time course of MR images also revealed biliary excretion of MnPC. CONCLUSION: We developed a new macromolecular MR agent, MnPC. The relaxivities of MnPC were higher than those of small molecular weight Gd-chelate. Hepatic uptake and biliary excretion of MnPC suggests that this agent is a new liver-specific MR agent.
Chromatography ; Gadolinium DTPA ; Liver ; Molecular Weight ; Relaxation

PURPOSE: To describe the MR findings of fibrous dysplasia. SUBJECTS AND METHODS: MR images of fibrousdysplasia in 13 pathologically proved cases were retrospectively analyzed regarding the signal intensity, hypointense rind, internal septations, cortical disruption, soft tissue extension, and the pattern of contrast enhancement. RESULTS: All cases showed low signal intensity on T1-weighted images. On T2-weighted images, 8cases(62%) were hyperintense and 5 cases(38%) hypointense. Hypointense rind was seen in 10 cases(77%), internal septations in 3 cases(23%), and cystic change in 2 cases(15%). Soft tissue extension was observed in fourcases(31%) including one case with pathologic fracture. After Gd-DTPA infusion, central contrast enhancement wasnoted in 8 cases(73%) and peripheral rim enhancement in 3 cases(23%). Pathologically, hypointensity on T2-weighted images was due to numerous bony trabeculae. CONCLUSION: Hypointensity on T1W1 and hyperintensity(62%) or hypointensity(38%) on T2W1 as well as contrast enhancement in fibrous dysplasia depend on degree of cellularity, collagen, cystic and hemorrhagic changes, and bony trabeculae.
Fractures, Spontaneous ; Gadolinium DTPA ; Radiography ; Retrospective Studies

PURPOSE: To assess the value of the bolus-tagging method for improving the image quality of contrast-enhanced MR abdominal angiography, and to evaluate the relationship between peak arterial enhancement time and patients' age, weight and heart rate. MATERIALS AND METHODS: Contrast-enhanced 3D FISP abdominal MR angiography was performed in 81 patients during a four-month period. The bolus-tagging method was used in a study group comprising 33 patients, and to this end, 1 ml of Gd-DTPA (gadolinium-diethylenetriamine penta-acetic acid) was administered. thirty sequential images (1 image/sec) were then obtained using turbo-FLASH sequencing. After determining peak arterial enhancement time from the time-to-signal intensity curve, optimal scan delay time can be calculated according to the formula used in our patient series. The 48 patients in whom the bolus-tagging method was not used comprised the control group ; in the study group scanning commenced at the optimal scan delay time (and at 10 seconds in the control group) after the administration of 0.2 mM/kg Gd-DTPA using an automatic power injector. Using a three-point scale we evaluated and compared between the two groups the success with which arterial images were obtained. In addition, vascular visibility -an indication of the quality of arteries and veins-was determined using a four-point scale. In the study group, the relationship between peak arterial enhancement time and patients' age, weight heart rate was also assessed. RESULTS: Pure arterial images were successfully obtained in 32 patients (97%) in the study group and in 40 (83%) in the control group. This difference was not statistically significant (p>.05). With regard to vascular visibility, diagnostic arterial images were seen in 30 patients (91%) in the study group and in 33 patients (69%) in the control group; arterial visibility was significantly better in the study group (p=.0197). On the other hand, the diagnostic venous images were seen in 31 patients (94%) in the study group and in 36 (75%) in the control group; there was no significant difference between the two groups (p=.2367). Peak arterial enhancement time increased significantly with age (r=.443, p=.0098); no correlation,however was seen between peak arterial enhancement time and weight (p>.05) or heart rate (p>.05). CONCLUSION: Used with contrast-enhanced 3-D FISP MR abdominal angiography, the bolus-tagging method provides better arterial visibility. Peak arterial enhancement time increased significantly with age.
Angiography* ; Arteries ; Gadolinium ; Gadolinium DTPA ; Hand ; Heart Rate ; Humans

PURPOSE: To assess the value of the bolus-tagging method for improving the image quality of contrast-enhanced MR abdominal angiography, and to evaluate the relationship between peak arterial enhancement time and patients' age, weight and heart rate. MATERIALS AND METHODS: Contrast-enhanced 3D FISP abdominal MR angiography was performed in 81 patients during a four-month period. The bolus-tagging method was used in a study group comprising 33 patients, and to this end, 1 ml of Gd-DTPA (gadolinium-diethylenetriamine penta-acetic acid) was administered. thirty sequential images (1 image/sec) were then obtained using turbo-FLASH sequencing. After determining peak arterial enhancement time from the time-to-signal intensity curve, optimal scan delay time can be calculated according to the formula used in our patient series. The 48 patients in whom the bolus-tagging method was not used comprised the control group ; in the study group scanning commenced at the optimal scan delay time (and at 10 seconds in the control group) after the administration of 0.2 mM/kg Gd-DTPA using an automatic power injector. Using a three-point scale we evaluated and compared between the two groups the success with which arterial images were obtained. In addition, vascular visibility -an indication of the quality of arteries and veins-was determined using a four-point scale. In the study group, the relationship between peak arterial enhancement time and patients' age, weight heart rate was also assessed. RESULTS: Pure arterial images were successfully obtained in 32 patients (97%) in the study group and in 40 (83%) in the control group. This difference was not statistically significant (p>.05). With regard to vascular visibility, diagnostic arterial images were seen in 30 patients (91%) in the study group and in 33 patients (69%) in the control group; arterial visibility was significantly better in the study group (p=.0197). On the other hand, the diagnostic venous images were seen in 31 patients (94%) in the study group and in 36 (75%) in the control group; there was no significant difference between the two groups (p=.2367). Peak arterial enhancement time increased significantly with age (r=.443, p=.0098); no correlation,however was seen between peak arterial enhancement time and weight (p>.05) or heart rate (p>.05). CONCLUSION: Used with contrast-enhanced 3-D FISP MR abdominal angiography, the bolus-tagging method provides better arterial visibility. Peak arterial enhancement time increased significantly with age.
Angiography* ; Arteries ; Gadolinium ; Gadolinium DTPA ; Hand ; Heart Rate ; Humans

PURPOSE: We wanted to investigate the use of gadolinium based contrast agent (Gd-DTPA) for computed tomography (CT), and we also wanted to assess the effects of valuable injection parameters on enhancement in an experimental rabbit brain model. MATERIALS AND METHODS: In vitro, attenuation measurements of serial dilutions of Gd-DTPA and iopromide were compared. In five rabbits, single level dynamic gadolinium-enhanced brain CT studies were obtained using different injection parameters. A comparison CT scan after iopromide administration was performed. The time-attenuation curves of the brain vessel and parenchyma were obtained and the magnitude of enhancement (Hmax) and the time to peak enhancement (Tmax) were analyzed. RESULTS: In vitro, the attenuation coefficient of undiluted Gd-DTPA (2,578 HU) was higher than that of iopromide (1,761 HU) at equimolar concentrations. In 5 rabbits, the time-attenuation curve demonstrated a distinct pattern with peak enhancement only in the brain vessel, but not in the brain parenchyma. There was increasing linear relationship between the injection rate of Gd-DTPA and Hmax, and a declining linear relationship with Tmax. The higher the concentration of Gd-DTPA, the higher Hmax was, but no significant difference was found for the Tmax. Higher volumes of Gd-DTPA revealed a higher Hmax and a delayed Tmax. CONCLUSION: Enhancement of the brain parenchyma on gadolinium-enhanced CT is minimal, while enhancement of the brain vessels is distinctive. The most important factor affecting Hmax of the vessel is the concentration of the contrast medium and the most important factor affecting Tmax of the vessel is volume of the contrast medium. The gadolinium-based contrast agent may be an reasonable alternative contrast agent for brain CT, and especially in cerebral vessels, and it may also be advantageous for brain parenchyma of those patients with BBB dysfunction.
Brain* ; Gadolinium DTPA ; Gadolinium* ; Humans ; Rabbits ; Tomography, X-Ray Computed

PURPOSE: The water exchange rate between bulk water and bound water is an important parameter in deciding the efficiency of paramagnetic contrast agents. In this study, we evaluated the water exchange rates of various Gd-chelates using oxygen-17 NMR technique. MATERIAL AND MEHTODS: The samples (Gd-DTPA, Gd-DTPA-BMA, Gd-DOTA, Gd-EOB-DTPA) were prepared by mixing 5% (17)O-enriched water (Isotech, USA). The pH of the samples was adjusted to physiological value (pH=7.0) by buffer solution. The variable temperature (17)O-NMR measurements were performed using Bruker-600 (14.1 T, 81.3 MHz) spectrometer. Bruker VT-1000 temperature control units were used to stabilize the temperature. The (17)O spin-spin relaxation times (T2) were measured using Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence with 24 echo trains. The variable temperature T2 relaxation data were then fitted into Solomon-Bloembergen equations using least square fit algorithm to estimate the water exchange times. RESULTS: From the measured (17)O-NMR relaxation rates, the determined water exchange rates at 300K are : 0.42 microsecond for Gd-DTPA, 1.99 microsecond for Gd-DTPA-BMA, 0.27 microsecond for Gd-DOTA, and 0.11 microsecond for Gd-EOB-DTPA. The Gd-DTPA-BMA showed slowest exchange whereas Gd-EOB-DTPA had fastest water exchange rate. In addition, it was found that the water exchange rates of all samples had exponential temperature dependence with different decay constant. CONCLUSION: (17)O-NMR relaxation rate measurements, when combined with variable temperature technique, provide a solid tool for studying water exchange rate, which is very important in investigating the detailed mechanism of relaxation enhancement effect of the paramagnetic contrast agents.
Contrast Media* ; Gadolinium DTPA ; Hydrogen-Ion Concentration ; Relaxation

We report CT and MR findings in tow cases of primary malignant melanoma of the vagina, one arising from cervicovaginal junction mimicking squamous cell carcinoma of the cervix and the other one recurring at vagina after resection. Two cases of malignant melanoma had high-attenuation on CT and high signal intensity on T1-weighted MR images and enhanced well after gadopentetate dimeglumine administration.
Carcinoma, Squamous Cell ; Cervix Uteri ; Female ; Gadolinium DTPA ; Melanoma* ; Vagina*

We report CT and MR findings in tow cases of primary malignant melanoma of the vagina, one arising from cervicovaginal junction mimicking squamous cell carcinoma of the cervix and the other one recurring at vagina after resection. Two cases of malignant melanoma had high-attenuation on CT and high signal intensity on T1-weighted MR images and enhanced well after gadopentetate dimeglumine administration.
Carcinoma, Squamous Cell ; Cervix Uteri ; Female ; Gadolinium DTPA ; Melanoma* ; Vagina*

PURPOSE: To optimize MR imaging pulse sequences in the imaging of hepatic hemangioma and to evaluate on dynamic MR imaging the enhancing characteristics of the lesions. MATERIALS AND METHODS: Twenty patients with 35 hemangiomas were studied by using Turbo-spin-echo (TSE) sequence (T2-weighted, T2- and heavily T2-weighted breath-hold) and T1-weighted FLASH imaging acquired before, immediately on, and 1, 3 and 5 minutes after injection of a bolus of Gd-DTPA (0.1 mmol/kg). Phased-array multicoil was employed. Images were quantitatively analyzed for lesion-to-liver signal difference to noise ratios (SD/Ns), and lesion-to-liver signal ratios (H/Ls), and qualitatively analyzed for lesion conspicuity. The enhancing characteristics of the hemangiomas were described by measuring the change of signal intensity as a curve in T1-weighted FLASH dynamic imaging. RESULTS: ForT2-weighted images, breath-hold T2-weighted TSE had a slightly higher SD/N than other pulse sequences, but there was no statistical difference in three fast pulse sequences (p=0.211). For lesion conspicuity, heavily T2-weighted breath-hold TSE images was superior to T2-weighted breath-hold or non-breath-hold TSE (H/L, 5.75, 3.81, 2.87, respectively, p<0.05). T2-weighted breath-hold TSE imaging was more effective than T2-weighted TSE imaging in removing lesion blurring or lack of sharpness, and there was a 12-fold decrease in acquisition time (20 sec versus 245 sec). T1-weighted FLASH dynamic images of normal liver showed peak enhancement at less than 1 minute, and of hemangioma at more than 3 minutes; the degree of enhancement for hemangioma decreased after a 3 minute delay. CONCLUSION: T2-weighted breath-hold TSE imaging and Gd-DTPA enhanced FLASH dynamic imaging with 5 minutes delay are sufficient for imaging hepatic hemangiomas.
Gadolinium DTPA ; Hemangioma* ; Humans ; Liver ; Magnetic Resonance Imaging ; Noise