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

OBJECTIVE: To compare P792 (gadomelitol, a rapid clearance blood pool MR contrast agent) with gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA), a standard extracellular agent, for their suitability to diagnose a pulmonary embolism (PE) during a first-pass perfusion MRI and 3D contrast-enhanced (CE) MR angiography (MRA). MATERIALS AND METHODS: A perfusion MRI or CE-MRA was performed in a rabbit PE model following the intravenous injection of a single dose of contrast agent. The time course of the pulmonary vascular and parenchymal enhancement was assessed by measuring the signal in the aorta, pulmonary artery, and lung parenchyma as a function of time to determine whether there is a significant difference between the techniques. CE-MRA studies were evaluated by their ability to depict the pulmonary vasculature and following defects between 3 seconds and 15 minutes after a triple dose intravenous injection of the contrast agents. RESULTS: The P792 and Gd-DOTA were equivalent in their ability to demonstrate PE as perfusion defects on first pass imaging. The signal from P792 was significantly higher in vasculature than that from Gd-DOTA between the first and the tenth minutes after injection. The results suggest that a CE-MRA PE could be reliably diagnosed up to 15 minutes after injection. CONCLUSION: P792 is superior to Gd-DOTA for the MR diagnosis of PE.
Animals ; Contrast Media/administration & dosage ; Heterocyclic Compounds/administration & dosage/*diagnostic use ; Imaging, Three-Dimensional ; Injections, Intravenous ; Magnetic Resonance Angiography/*methods ; Magnetic Resonance Imaging/*methods ; Organometallic Compounds/administration & dosage/*diagnostic use ; Pulmonary Embolism/*diagnosis ; Rabbits

BACKGROUND: Cystatin C (cysC) is said to be an ideal marker for glomerular filtration rate (GFR), independent of external factors such as age, nutrition and inflammation. The authors compared the accuracy and precision of cysC-based and creatinine (Cr)-based GFR estimates using Cr51-EDTA GFR method as a reference. METHODS: Serum concentrations of cysC and Cr were measured in adults over 17 yr (n=170) and children below 17 yr (n=79) who had had GFR estimated by Cr51-EDTA method. CysC-based GFR was estimated by the formula of Thierry [CysC-based GFR estimates (mL/min/1.73 m2)=78 x (1/cysC, in mg/L)+4] and Cr-based GFR by the formula of modified Modification of Diet in Renal Disease [MDRD II, Cr-based GFR estimates (mL/min/1.73 m2)=186 x (Scr)(-1.154) x (Age)(-0.203) x 0.742 (for a female patient) x 1.212 (for a black patient). RESULTS: In comparison with Cr51-EDTA GFR, in children below 17 yr, the bias +/- standard deviation (SD) of cysC-based and Cr-based GFR estimates were 7.5 +/- 6.1 and 106.5 +/- 98.2, respectively, in the range of below 90 of Cr51-EDTA GFR (mL/min/1.73 m2), and 33.7 +/- 33.0 and 174.4 +/- 18.8 in the range of over 90. In adults over 17 yr, the respective figures were 13.1 +/- 11.0 and 17.4 +/- 29.8 in below 90, and 21.2 +/- 20.1 and 83.6 +/- 108.8 in over 90 of Cr51-EDTA GFR. CONCLUSIONS: CysC-based GFR estimates show acceptable ranges of biases over the whole age and GFR ranges. CysC-based GFR estimates is considered to be the marker for GFR, which could be used without limitation of age and GFR ranges.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biological Markers/urine ; Child ; Chromium Radioisotopes/diagnostic use ; Creatinine/*urine ; Cystatin C ; Cystatins/*urine ; Edetic Acid/diagnostic use ; Female ; Glomerular Filtration Rate/*physiology ; Humans ; Male ; Middle Aged ; Organometallic Compounds/diagnostic use

Hepatocyte specific contrast agents including gadoxetic acid and gadobenate dimeglumine are very useful to diagnose various benign and malignant focal hepatic lesions and even helpful to estimate hepatic functional reservoir. The far delayed phase image referred to as the hepatobiliary phase makes the sensitivity of detection for malignant focal hepatic lesions increased, but specificity of malignant diseases, including hepatocellular carcinoma, metastasis and cholangiocarcinoma, characterization remained to be undetermined.
Carcinoma, Hepatocellular/radiography ; Cholangiocarcinoma/radiography ; Contrast Media/chemistry/*diagnostic use ; Hemangioma/radiography ; Humans ; Liver Diseases/*radiography ; Liver Neoplasms/radiography ; Magnetic Resonance Imaging ; Meglumine/*analogs & derivatives/chemistry/diagnostic use ; Organometallic Compounds/chemistry/*diagnostic use

Gadobenate dimeglumine-enhanced magnetic resonance (MR) imaging simultaneously provides both morphological and functional information by the acquisition of dynamic and hepatobiliary-phase imaging. Focal lesions with no functioning hepatocytes, where hepatobiliary metabolism is blocked or inhibited, are generally unable to uptake and excrete gadobenate dimeglumine into the bile. Such lesions are typically malignant and usually appear hypointense as compared to the normal liver parenchyma as seen on hepatobiliary-phase imaging. However, various benign hepatic lesions may also be hypointense due to (a) the presence of no functioning hepatocytes, (b) damage to the functioning hepatocytes or (c) impairment of biliary function as depicted on hepatobiliary-phase imaging. All of these imaging features may result in recognition of the benign hepatic lesions as hepatic malignancies. As depicted on three-hour delayed hepatobiliary-phase imaging, peripheral iso/hyperintensity due to fibrotic tissue compared to the hypointense center with a fuzzy margin may be a clue for the presence of a benign hepatic lesion. In contrast, peripheral hypointensity due to rich tumoral cellularity compared to the center with a clear margin may favor an indication of the presence of a malignant hepatic lesion.
Adult ; Aged ; Contrast Media/*diagnostic use ; Diagnosis, Differential ; Female ; Humans ; Image Enhancement/methods ; Liver/pathology ; Liver Diseases/diagnosis/pathology ; Liver Neoplasms/*diagnosis/*pathology ; Magnetic Resonance Imaging/*methods ; Male ; Meglumine/*analogs & derivatives/diagnostic use ; Middle Aged ; Organometallic Compounds/*diagnostic use ; Time

OBJECTIVE: To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). MATERIALS AND METHODS: A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. RESULTS: Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. CONCLUSION: UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.
Adult ; Case-Control Studies ; Contrast Media/diagnostic use ; Female ; Humans ; Leiomyoma/*therapy ; Magnetic Resonance Imaging, Interventional/*methods ; Meglumine/diagnostic use ; Middle Aged ; Organometallic Compounds/diagnostic use ; Questionnaires ; Retrospective Studies ; Treatment Outcome ; Uterine Artery Embolization/*methods ; Uterine Neoplasms/*therapy

OBJECTIVE: To investigate the efficacy of gadobenate dimeglumine (Gd-BOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. MATERIALS AND METHODS: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of Gd-BOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. RESULTS: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. CONCLUSION: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.
Adenoma, Liver Cell/*diagnosis ; Adult ; Aged ; *Contrast Media ; Female ; Human ; Image Enhancement ; Liver Neoplasms/*diagnosis ; Magnetic Resonance Imaging/*methods ; Male ; Meglumine/*analogs & derivatives/*diagnostic use ; Middle Age ; Organometallic Compounds/*diagnostic use

OBJECTIVE: To compare the effect of imaging time delay on the MR detection of intracerebral metastases using single dose gadobutrol. MATERIALS AND METHODS: Twenty-one patients with intracerebral metastases underwent contrast-enhanced MR with three-dimensional T1-weighted sequence at 1 minute, 5 minutes and 10 minutes after a single dose injection of gadobutrol. One hundred index metastatic lesions (1 to 30 mm; median, 7 mm) were chosen for the analysis. For the qualitative analysis, lesion conspicuity were assessed on a 1 (worst) to 5 (best) scale of the index lesions by an expert reader. For the quantitative analysis, signal intensity (SI) of enhancing lesions and normal parenchyma was measured to determine the contrast rate (CR, %) ([postcontrast SI lesion - postcontrast SI white matter] x 100 / postcontrast SI white matter) and the enhancement rate (ER, %) ([postcontrast SI lesion - baseline SI gray matter] x 100 / baseline SI gray matter). Statistical comparisons were made between three different time delays. RESULTS: Lesion conspicuity did not differ significantly among the three time delays (p = 0.097). Although the SI, CR and ER of lesions did not reveal any significant difference between 1 minute and 5 minutes delayed images, both the 1 minute and 5 minutes delayed images showed significantly higher CRs of lesions compared with the 10 minutes delayed images (p = 0.004 and p = 0.001, respectively). CONCLUSION: With single dose gadobutrol, imaging time delay did not have an effect on lesion conspicuity. Both 1-minute and 5-minute-delayed imaging after gadobutrol injection appears to be effective for the detection of intracerebral metastases.
Adult ; Aged ; Aged, 80 and over ; Brain Neoplasms/*diagnosis/*secondary ; Contrast Media/administration & dosage/*diagnostic use ; Female ; Humans ; Image Enhancement/methods ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Observer Variation ; Organometallic Compounds/administration & dosage/*diagnostic use ; Time Factors

OBJECTIVE: To determine the prevalence of thyroid incidentalomas detected by time-resolved magnetic resonance angiography (TRMRA) and to evaluate their clinical significance by using an ultrasonographic (US) and cytologic correlation. MATERIALS AND METHODS: We retrospectively reviewed 2010 consecutive TRMRA examinations performed at our institution between August 2006 and April 2010. The TRMRA findings of thyroid incidentalomas were analyzed according to location, size, as well as vascularity, and were correlated with the US findings and cytologic results. Each nodule was classified as suspiciously malignant, indeterminate or probably benign according to the US criteria recommended by the Korean Society of Thyroid Radiology. RESULTS: A total of 102 incidentalomas were detected in 90 of 2010 patients (5%). TRMRA showed homogenous hypervascularity in 48 (47%), inhomogeneous hypervascularity in 46 (45%), and hypovascularity in 8 (8%) thyroid nodules. At follow-up study, out of 26 patients with 30 incidentalomas on TRMRA, 27 nodules were identified on US. Of the 27 nodules, 24 (89%) nodule were classified as indeterminate, two (7%) as probably benign, and one (4%) as suspiciously malignant. Among the 16 nodules with available cytopathologic results, 14 (82%) were benign, one (6%) was indeterminate, and one (6%) was malignant. CONCLUSION: Thyroid incidentalomas are found in 5% of TRMRA examinations. Although their presence does not necessarily indicate malignancy, nonspecific findings of detected incidentalomas on TRMRA require further evaluation by US.
Adult ; Aged ; Aged, 80 and over ; Contrast Media/diagnostic use ; Female ; Humans ; Incidental Findings ; Magnetic Resonance Angiography/*methods ; Male ; Middle Aged ; Organometallic Compounds/diagnostic use ; Prevalence ; Retrospective Studies ; Thyroid Neoplasms/*diagnosis/epidemiology/ultrasonography ; Thyroid Nodule/*diagnosis/epidemiology/ultrasonography

OBJECTIVE: To validate the optimal cardiac phase and appropriate acquisition window for three-dimensional (3D) whole-heart coronary magnetic resonance angiography (MRA) with a steady-state free precession (SSFP) sequence, and to compare image quality between SSFP and Gd-enhanced fast low-angle shot (FLASH) MR techniques at 1.5 Tesla (T). MATERIALS AND METHODS: Thirty healthy volunteers (M:F = 25:5; mean age, 35 years; range, 24-54 years) underwent a coronary MRA at 1.5T. 3D whole-heart coronary MRA with an SSFP was performed at three different times: 1) at end-systole with a narrow (120-msec) acquisition window (ESN), 2) mid-diastole with narrow acquisition (MDN); and 3) mid-diastole with wide (170-msec) acquisition (MDW). All volunteers underwent a contrast enhanced coronary MRA after undergoing an unenhanced 3D true fast imaging with steady-state precession (FISP) MRA three times. A contrast enhanced coronary MRA with FLASH was performed during MDN. Visibility of the coronary artery and image quality were evaluated for 11 segments, as suggested by the American Heart Association. Image quality was scored by a five-point scale (1 = not visible to 5 = excellent). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated at the proximal coronary arteries. RESULTS: The SSFP sequence rendered higher visibility coronary segments, higher image quality, as well as higher SNR and CNR than the Gd-enhanced FLASH technique at 1.5T (p < 0.05). The visibility of coronary segments, image quality, SNR and CNR in the ESN, MDN and MDW with SSFP sequence did not differ significantly. CONCLUSION: An SSFP sequence provides an excellent method for the 3D whole-heart coronary MRA at 1.5T. Contrast enhanced coronary MRA using the FLASH sequence does not help improve the visibility of coronary segments, image quality, SNR or CNR on the 3D whole-heart coronary MRA.
Adult ; *Contrast Media ; Coronary Vessels/*anatomy & histology ; Female ; Gadolinium/diagnostic use ; Humans ; Image Processing, Computer-Assisted ; *Imaging, Three-Dimensional ; Magnetic Resonance Angiography/*methods ; Male ; Middle Aged ; Organometallic Compounds/*diagnostic use ; Reference Values ; Young Adult