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

OBJECTIVE: This study was designed to determine the optimal mixture ratio of gadolinium and iodinated contrast agent for simultaneous direct MR arthrography and CT arthrography. MATERIALS AND METHODS: An in vitro study was performed utilizing mixtures of gadolinium at six different concentrations (0.625, 1.25, 2.5, 5.0, 10 and 20 mmol/L) and iodinated contrast agent at seven different concentrations (0, 12.5, 25, 37.5, 50, 75 and 92-99.9%). These mixtures were placed in tissue culture plates, and were then imaged with CT and MR (with T1-weighted sequences, proton-density sequences and T2-weighted sequences). CT numbers and signal intensities were measured. Pearson's correlation coefficients were used to assess the correlations between the gadolinium/iodinated contrast agent mixtures and the CT numbers/MR signal intensities. Scatter diagrams were plotted for all gadolinium/iodinated contrast agent combinations and two radiologists in consensus identified the mixtures that yielded the optimal CT numbers and MR signal intensities. RESULTS: The CT numbers showed significant correlation with iodinated contrast concentrations (r = 0.976, p < 0.001), whereas the signal intensities as measured on MR images showed a significant correlation with both gadolinium and iodinated contrast agent concentrations (r = -484 to -0.719, p < 0.001). A review of the CT and MR images, graphs, and scatter diagram of 42 combinations of the contrast agent showed that a concentration of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was the best combination for simultaneous CT and MR imaging. CONCLUSION: A mixture of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was found to be optimal for simultaneous direct MR arthrography and CT arthrography.
*Arthrography ; Contrast Media/*administration & dosage ; Gadolinium/administration & dosage/*diagnostic use ; Iohexol/administration & dosage/*analogs & derivatives/diagnostic use ; *Magnetic Resonance Imaging ; Meglumine/administration & dosage/*diagnostic use ; Organometallic Compounds/administration & dosage/*diagnostic use ; Phantoms, Imaging ; *Tomography, X-Ray Computed

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 identify and evaluate the lateral border zone by comparing the size and distribution of the abnormal signal area demonstrated by MR imaging with the infarct area revealed by pathological examination in a reperfused myocardial infarction cat model. MATERIALS AND METHODS: In eight cats, the left anterior descending coronary artery was occluded for 90 minutes, and this was followed by 90 minutes of reper-fusion. ECG-triggered breath-hold turbo spin-echo T2-weighted MR images were initially obtained along the short axis of the heart before the administration of contrast media. After the injection of Gadomer-17 and Gadophrin-2, contrast-enhanced T1-weighted MR images were obtained for three hours. The size of the abnormal signal area seen on each image was compared with that of the infarct area after TTC staining. To assess ultrastructural changes in the myocardium at the infarct area, lateral border zone and normal myocardium, electron microscopic examination was performed. RESULTS: The high signal area seen on T2-weighted images and the enhanced area seen on Gadomer-17-enhanced T1WI were larger than the enhanced area on Gadophrin-2-enhanced T1WI and the infarct area revealed by TTC staining; the difference was expressed as a percentage of the size of the total left ventricle mass (T2= 39.2 %; Gadomer-17 =37.25 % vs Gadophrin-2 = 29.6 %; TTC staining = 28.2 %; p < 0.05). The ultrastructural changes seen at the lateral border zone were compatible with reversible myocardial damage. CONCLUSION: In a reperfused myocardial infarction cat model, the presence and size of the lateral border zone can be determined by means of Gadomer-17- and Gadophrin-2-enhanced MR imaging.
Animal ; Cats ; Contrast Media ; Gadolinium ; Magnetic Resonance Imaging/*methods ; Mesoporphyrins/diagnostic use ; Metalloporphyrins/diagnostic use ; Myocardial Infarction/*pathology ; Myocardial Reperfusion ; Myocardium/pathology ; Support, Non-U.S. Gov't

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 if a combination of ferucarbotran-enhanced T2*weighted-gradient echo (T2*W-GRE) and T2-weighted turbo spin echo (T2W-TSE) images in gadolinium- and ferucarbotran-enhanced MRI has additive efficacy compared to each image alone for detecting small (< or = 2.0 cm) hepatocellular carcinoma (HCC) lesions in a group of cirrhotic patients and metastases in a group of non-cirrhotic patients. MATERIALS AND METHODS: Two readers retrospectively analyzed gadolinium- and ferucarbotran-enhanced T2*W-GRE, T2W-TSE, and combined T2*W-GRE/T2W-TSE images of 119 patients with 157 HCCs and 32 patients with 98 metastases. The diagnostic accuracy and sensitivity for each image set and the combined set were evaluated using the alternative-free response receiver operating characteristic method. RESULTS: The mean area under the curve value of the combined set (0.966) tended to be better than that for each individual image set (T2W-TSE [0.910], T2*W-GRE [0.892]). Sensitivities in the combined set were higher than those in each individual image set for detecting HCC (mean, 93.0% versus 81.6% and 86.7%, respectively, p < 0.01). Sensitivities in the combined set and the T2W-TSE set were the same for detecting metastases, and both were higher than the sensitivity seen in the T2*W-GRE set (mean, 97.5% versus 85.2 %, p < 0.01). CONCLUSION: Combining ferucarbotran-enhanced T2*W-GRE and T2W-TSE has additive efficacy for detecting HCC in cirrhotic patients, but T2W-TSE is preferred for detecting metastases in non-cirrhotic patients.
Adult ; Aged ; Carcinoma, Hepatocellular/*diagnosis ; Contrast Media/*administration & dosage ; Female ; Gadolinium DTPA/*diagnostic use ; Humans ; Iron/*diagnostic use ; Liver Neoplasms/*diagnosis/secondary ; *Magnetic Resonance Imaging/methods ; Male ; Middle Aged ; Observer Variation ; Oxides/*diagnostic use ; Predictive Value of Tests ; Sensitivity and Specificity

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

We report a case of early non-invasive diagnosis of acute eosinophilic myopericarditis (AEM) by cardiovascular magnetic resonance (CMR) before cardiac biopsy. A 35-yr-old woman presented with a flu-like illness, followed by pleuritic chest pain and shortness of breath. Transthoracic echocardiography revealed mild left ventricular (LV) systolic dysfunction with borderline LV wall thickness and moderate pericardial effusion. The patient had peripheral eosinophilia and CMR was performed immediately at first day of visit before cardiac biopsy. CMR showed diffuse subepicardial high T2 signals and diffuse late gadolinium enhancement in LV. Steroid therapy was immediately initiated and patient's symptom was rapidly improved. Endomyocardial biopsy at hospital day 3 reported multifocal mild infiltration of eosinophils and lymphocytes. The patient was finally confirmed as acute eosinophilic myopericarditis. This presentation emphasizes on the role of CMR which enables early non-invasive diagnosis of AEM and visualize the extent of the myocarditis.
Adult ; Early Diagnosis ; Echocardiography ; Eosinophilia/*diagnosis ; Female ; Gadolinium/diagnostic use ; Humans ; Magnetic Resonance Imaging ; Pericarditis/*diagnosis/*drug therapy/pathology ; Ventricular Dysfunction, Left/diagnosis/drug therapy/pathology