Injection Of Gadopentetate Dimeglumine Research Articles

Can gadolinium contrast agents be replaced with saline for direct MR arthrography of the hip? A pilot study with arthroscopic comparison.

To compare image quality and diagnostic performance of preoperative direct hip magnetic resonance arthrography (MRA) performed with gadolinium contrast agent and saline solution. IRB-approved retrospective study of 140 age and sex-matched symptomatic patients with femoroacetabular impingement, who either underwent intra-articular injection of 15-20mL gadopentetate dimeglumine (GBCA), 2.0mmol/L ("GBCA-MRA" group, n = 70), or 0.9% saline solution ("Saline-MRA" group, n = 70) for preoperative hip MRA and subsequent hip arthroscopy. 1.5 T hip MRA was performed including leg traction. Two readers assessed image quality using a 5-point Likert scale (1-5, excellent-poor), labrum and femoroacetabular cartilage lesions. Arthroscopic diagnosis was used to calculate diagnostic accuracy which was compared between groups with Fisher's exact tests. Image quality was compared with the Mann-Whitney U tests. Mean age was 33years ± 9, 21% female patients. Image quality was excellent (GBCA-MRA mean range, 1.1-1.3 vs 1.1-1.2 points for Saline-MRA) and not different between groups (all p > 0.05) except for image contrast which was lower for Saline-MRA group (GBCA-MRA 1.1 ± 0.4 vs Saline-MRA 1.8 ± 0.5; p < 0.001). Accuracy was high for both groups for reader 1/reader 2 for labrum (GBCA-MRA 94%/ 96% versus Saline-MRA 96%/93%; p > 0.999/p = 0.904) and acetabular (GBCA-MRA 86%/ 83% versus Saline-MRA 89%/87%; p = 0.902/p = 0.901) and femoral cartilage lesions (GBCA-MRA 97%/ 99% versus Saline-MRA 97%/97%; both p > 0.999). Diagnostic accuracy and image quality of Saline-MRA and GBCA-MRA is high in assessing chondrolabral lesions underlining the potential role of non-gadolinium-based hip MRA. • Image quality of Saline-MRA and GBCA-MRA was excellent for labrum, acetabular and femoral cartilage, ligamentum teres, and the capsule (all p > 0.18). • The overall image contrast was lower for Saline-MRA (Saline-MRA 1.8 ± 0.5 vs. GBCA-MRA 1.1 ± 0.4; p < 0.001). • Diagnostic accuracy was high for Saline-MRA and GBCA-MRA for labrum (96% vs. 94%; p > 0.999), acetabular cartilage damage (89% vs. 86%; p = 0.902), femoral cartilage damage (97% vs. 97%; p > 0.999), and extensive cartilage damage (97% vs. 93%; p = 0.904).

Impacts of Gadolinium-Based MRI contrast Agent on Hematological and Biochemical Tests for the Human Volunteers.

Magnetic resonance imaging (MRI) Gadolinium-Containing contrast agents are used in combination with MRI in some situations. The effects of gadolinium-based MRI contrast agent (MAGNEVIST® Gadopentetate Dimeglumine Injection Bayer Standard 469 mg/ml (0.5 mmol/ml) on some hematological and biochemical tests for human male volunteers have been investigated. The study consisted of nine healthy individuals of human male volunteers; they were injected with intravenous (IV) contrast without being exposed to MRI. The cases are divided into four subgroups based on how long and how many times of blood samples were withdrawn after the intravenous (IV) contrast injection (9, 25, and 40 minutes). Blood samples were examined for twenty-seven hematological and biochemical parameters. The results proved that; after 9 min of injection with IV contrast, the WBCs count, LYM, MID%, and ALT decreased by 6%,6%, 4%, and 5%, respectively, and the concentration of GRA% and ESR increased by 5%. 25min after injection, concentrations of PLT increased significantly (P &lt; 0.05) by 4%, PCT %, LPCR %, MID, and ESR are increased non-significantly (P &gt; 0.05) by 4%, 5%, 7%, and 26%, respectively. After 40min of injections; MID, and MID% increased by 11% and 12%, respectively, and AST decreased by 4%. The maximum rise in ESR was increased by 31%. There was no substantial variation with time can be seen in electrolytes; Sodium (Na+), Potassium (K+), and Chloride (Cl-) under the effect of the intravenous contrast injection.

Fat-suppressed magnetic resonance volume interpolated examination for deep venous thrombosis compared with duplex sonography.

The aim of the present study was to evaluate magnetic resonance venography (MRV) scanned by breath-hold volume interpolated body examination with spectral fat saturation (VIBE-fs), combined with Dixon fat-suppressed VIBE (VIBE-Dixon) by using a 1.5T MR scanner for detecting deep venous thrombosis (DVT) compared with duplex sonography. A total of 31 patients with DVT were identified using duplex sonography and were enrolled in the present study for MRV examination, from the inferior vena cava to the ankle level after injection of gadopentetate dimeglumine. Venous segment-to-segment comparison was assessed for DVT detection between MRV and duplex sonography. A total of two radiologists separately performed subjective image quality assessment using a 5-point scale. Cohen's κ coefficient, Wilcoxon rank sum test and intraclass correlation coefficient values were used for statistical analysis. Of the 303 evaluated vein segments, duplex sonography identified 119 (39.3%; 119/303) venous segments with thrombus, while MRV detected 170 (56.1%; 170/303) venous segments with thrombus. The diagnostic agreement rate of DVT between duplex sonography and MRV was poor in the deep femoral vein and anterior tibial veins, while it was excellent in the inferior vena cava (IVC), common iliac vein, external iliac vein, femoral vein, popliteal vein, posterior tibial veins and peroneal veins. In addition, poor reliability was detected in the deep femoral vein, anterior tibial veins and peroneal veins, but good to excellent reliability was observed in IVC, common iliac vein, external iliac vein, femoral vein, popliteal vein and posterior tibial veins. Furthermore, image quality scores of each venous segment between the two radiologists indicated no statistical difference. Therefore, MRV scanned using VIBE-fs for the suprainguinal and VIBE-Dixon for the infrainguinal region may be a useful method for detecting DVT compared with duplex sonography. The results of present study proved this MR protocol to be a beneficial alternative imaging modality for the detection of DVT when duplex sonography is inadequate or not able to be performed.

Significance of Endolymphatic Hydrops Herniation Into the Semicircular Canals Detected on MRI.

The objective of this study was to investigate the relationship between endolymphatic hydrops (EH) and hearing level or vestibular symptoms by focusing on EH herniation into the semicircular canal (SCC). Retrospective study. University hospital. The study included 1,548 ears of 775 patients who underwent magnetic resonance imaging (MRI) examination in our university hospital to investigate possible EH. MRI was performed 4 hours after intravenous injection of a standard dose of gadodiamide hydrate and/or 24 hours after intratympanic injection of gadopentetate dimeglumine diluted eightfold. The hearing threshold and vestibular symptoms were compared between ears with unilateral and bilateral EH herniation into the SCC and between ears having vestibular EH adjacent to the stapes footplate with or without EH herniation. Forty-four ears (19 men and 25 women, mean age 53.6 yr) showed EH herniation into the SCC. The average hearing thresholds at 500 to 4000 Hz and presence of vestibular EH adjacent to the stapes footplate were significantly higher in ears with unilateral herniation than in those with bilateral herniation. The average hearing thresholds at 500 and 1000 Hz were significantly higher in the group of ears having adjacency with herniation than in those without herniation. Vestibular symptoms did not differ significantly between groups. Unilateral herniation occurs with EH progression. Bilateral herniation may occur regardless of EH progression and might be influenced by other factors that alter the membranous labyrinth.

Stable gadolinium based nanoscale lyophilized injection for enhanced MR angiography with efficient renal clearance

There is a great demand to develop high-relaxivity nanoscale contrast agents for magnetic resonance (MR) angiography with high resolution. However, there should be more focus on stability, ion leakage and excretion pathway of the intravenously injected nanoparticles, which are closely related to their clinic potentials. Herein, uniform ultrasmall-sized NaGdF4 nanocrystal (sub-10 nm) was synthesized using a facile high temperature organic solution method, and the nanocrystals were modified by a ligand-exchange approach using PEG-PAA di-block copolymer. The PEG-PAA modified NaGdF4 nanocrystal (denoted as ppNaGdF4 nanocrystal) exhibited a high r1 relaxivity which was twice of commercially used gadopentetate dimeglumine (Gd-DTPA) injection. MR angiography on rabbit using ppNaGdF4 nanocrystal at a low dose showed enhanced vascular details and long circulation time. Lyophilized powder of ppNaGdF4 nanocrystals have been successfully prepared without aggregation or reduction of MR performance, indicating the stability and an effective way to store this nanoscale contrast agent. No haemolysis was induced by ppNaGdF4 nanocrystal, and an extremely low leakage of gadolinium ions was confirmed. Furthermore, efficient renal excretion was one of the clearance pathways of ppNaGdF4 nanocrystal according to both the time dependent distribution data in blood and tissues and MR images. The in vivo toxicity evaluation further validated the great potential as a clinical agent for blood pool imaging.

The relationship between endolymphatic hydrops in the vestibule and low-frequency air-bone gaps.

To investigate the relationship between endolymphatic hydrops and hearing level, focusing on significant vestibular endolymphatic hydrops adjacent to the stapes footplate and low-frequency air-bone gaps. Retrospective study. The study included 1,548 ears from 775 patients who underwent magnetic resonance imaging examination in our university hospital to investigate possible endolymphatic hydrops between January 2012 and December 2015. Ears were evaluated by magnetic resonance imaging performed 4 hours after intravenous injection of a standard dose of gadodiamide hydrate and/or 24 hours after intratympanic injection of gadopentetate dimeglumine diluted eightfold. Comparison of hearing thresholds on pure-tone audiometry was performed between ears having endolymphatic hydrops adjacent to the stapes footplate and those having nonadjacent endolymphatic hydrops. Forty-one ears (22 men and 19 women, mean age 48.4 years) showed significant cochlear and vestibular endolymphatic hydrops adjacent to the stapes footplate, and 79 ears (30 men and 49 women, mean age 45.0 years) showed significant nonadjacent cochlear and vestibular endolymphatic hydrops. The average air-bone gap at 250 Hz was significantly higher in the group of ears with adjacent hydrops than in those with nonadjacent hydrops. The appearance of low-frequency air-bone gaps suggests deterioration of endolymphatic hydrops, particularly in ears with Ménière's disease, and could be a useful indicator for evaluating and treating patients with endolymphatic hydrops. 4. Laryngoscope, 128:1658-1662, 2018.

Imaging of endolymphatic spaces of internal ear in aged patients suffering from Meniere’s disease

Objective The research aimed at evaluating whether non-invasive endolymphatic MR imaging could be used in aged patients(≥60 years)suffering from Meniere’s disease. Methods Under guidance of nasal endoscopy, a diluted gadopentetate dimeglumine injection was administrated through eustachian tube into mid-ear cavity in four patients (≥60 years old) suffered from Meniere’s disease. 3D-FLAIR MRI scan was performed one day after the administration. Results The administration succeeded through eustachian tube into mid-ear cavity in those four patients. A rise of fluid level on tympanic membrane while administrating a diluted gadopentetated meglumine injection was observed. Imaging of inner ear endolymphatic spaces were visible in vestibule and cochlea in imaging of patient 1. As to patient 2, in cochlea the scala tympani of the first and second turns were enhanced while scala vestibule weren’t; Vestibules couldn’t be recognized. In images of patient 3, the scala tympani of the three turns in cochlea were enhanced while scala vestibule weren’t; Vestibules couldn’t be recognized. For Patient 4, in cochlea the scala tympani of the first turn were enhanced while scala vestibule weren’t, and the second turn was partially enhanced; and endolymphatic space of vestibule could be distinguished from perilymphatic space. Conclusions This technique could be adopted in investigation of Meniere’s disease in elderly patients. MR imaging of endolymphatic spaces in vestibule and cochlea can be visualized, which may partially provide data for diagnosis of Meniere’s disease. Key words: Endolymphatic imaging; Meniere’s disease; Magnetic resonance imaging

Global and Regional Brain Assessment with Quantitative MR Imaging in Patients with Prior Exposure to Linear Gadolinium-based Contrast Agents.

Purpose To assess the association of global and regional brain relaxation times in patients with prior exposure to linear gadolinium-based contrast agents (GBCAs). Materials and Methods The institutional review board approved this cross-sectional study. Thirty-five patients (nine who had received GBCA gadopentetate dimeglumine injections previously [one to eight times] and 26 patients who did not) who underwent brain magnetic resonance (MR) imaging with a mixed fast spin-echo pulse sequence were assessed. The whole brain was segmented according to white and gray matter by using a dual-clustering algorithm. In addition, regions of interest were measured in the globus pallidus, dentate nucleus, thalamus, and pons. The Mann-Whitney U test was used to assess the difference between groups. Multiple regression analysis was performed to assess the association of T1 and T2 with prior GBCA exposure. Results T1 values of gray matter were significantly shorter for patients with than for patients without prior GBCA exposure (P = .022). T1 of the gray matter of the whole brain (P < .001), globus pallidus (P = .002), dentate nucleus (P = .046), and thalamus (P = .026) and T2 of the whole brain (P = .004), dentate nucleus (P = .023), and thalamus (P = .002) showed a significant correlation with the accumulated dose of previous GBCA administration. There was no significant correlation between T1 and the accumulated dose of previous GBCA injections in the white matter (P = .187). Conclusion Global and regional quantitative assessments of T1 and T2 demonstrated an association with prior GBCA exposure, especially for gray matter structures. The results of this study confirm previous research findings that there is gadolinium deposition in wider distribution throughout the brain. © RSNA, 2016 Online supplemental material is available for this article.

Signal Increase on Unenhanced T1-Weighted Images in the Rat Brain After Repeated, Extended Doses of Gadolinium-Based Contrast Agents: Comparison of Linear and Macrocyclic Agents.

ObjectivesIn this prospective preclinical study, we evaluated T1-weighted signal intensity in the deep cerebellar nuclei (CN) and globus pallidus (GP) up to 24 days after repeated administration of linear and macrocyclic gadolinium-based contrast agents (GBCAs) using homologous imaging and evaluation methods as in the recently published retrospective clinical studies. In a second part of the study, cerebrospinal fluid (CSF) spaces were evaluated for contrast enhancement by fluid-attenuated magnetic resonance imaging (MRI).Materials and MethodsSixty adult male Wistar-Han rats were randomly divided into a control and 5 GBCA groups (n = 10 per group). The administered GBCAs were gadodiamide, gadopentetate dimeglumine, and gadobenate dimeglumine (linear GBCAs) as well as gadobutrol and gadoterate meglumine (macrocyclic GBCAs) and saline (control). Over a period of 2 weeks, the animals received 10 intravenous injections at a dose of 2.5 mmol Gd/kg body weight, each on 5 consecutive days per week. Before GBCA administration, as well as 3 and 24 days after the last injection, a whole-brain MRI was performed using a standard T1-weighted 3-dimensional turbo spin echo sequence on a clinical 1.5 T scanner. The ratios of signal intensities in deep CN to pons (CN/Po) and GP to thalamus (GP/Th) were determined. For the evaluation of the CSF spaces, 18 additional rats were randomly divided into 6 groups (n = 3 per group) that received the same GBCAs as in the first part of the study. After MR cisternography for anatomical reference, a fluid-attenuated inversion recovery sequence was performed before and 1 minute after intravenous injection of a dose of 1 mmol Gd/kg body weight GBCA or saline.ResultsA significantly increased signal intensity ratio of CN/Po was observed 3 and 24 days after the last injection of gadodiamide and gadobenate dimeglumine. No significant changes were observed between the 2 time points. Gadopentetate dimeglumine injection led to a moderately elevated but statistically not significant CN/Po signal intensity ratio. No increased CN/Po signal intensity ratios were determined in the MRI scans of rats that received macrocyclic GBCAs gadobutrol and gadoterate meglumine or saline. The ratio of signal intensity in GP/Th was not elevated in any group injected with GBCAs or saline. Enhanced signal intensities of CSF spaces were observed in the postcontrast fluid-attenuated inversion recovery images of all animals receiving GBCAs but not for saline.ConclusionsIn this animal study in rats, increased signal intensity in the CN was found up to 24 days after multiple, extended doses of linear GBCAs. However, in contrast to clinical reports, the signal enhancement in the GP was not reproduced, demonstrating the limitations of this animal experiment. The elevated signal intensities remained persistent over the entire observation period. In contrast, no changes of signal intensities in either the CN or the GP were observed for macrocyclic GBCAs. However, all GBCAs investigated were able to pass the blood-CSF barrier in rats to a certain, not yet quantified extent.

Parallel Comparative Studies on Mouse Toxicity of Oxide Nanoparticle- and Gadolinium-Based T1 MRI Contrast Agents.

Magnetic resonance imaging (MRI) contrast agents with high relaxivity are highly desirable because they can significantly increase the accuracy of diagnosis. However, they can be potentially toxic to the patients. In this study, using a mouse model, we investigate the toxic effects and subsequent tissue damage induced by three T1 MRI contrast agents: gadopentetate dimeglumine injection (GDI), a clinically used gadolinium (Gd)-based contrast agent (GBCAs), and oxide nanoparticle (NP)-based contrast agents, extremely small-sized iron oxide NPs (ESIONs) and manganese oxide (MnO) NPs. Biodistribution, hematological and histopathological changes, inflammation, and the endoplasmic reticulum (ER) stress responses are evaluated for 24 h after intravenous injection. These thorough assessments of the toxic and stress responses of these agents provide a panoramic description of safety concerns and underlying mechanisms of the toxicity of contrast agents in the body. We demonstrate that ESIONs exhibit fewer adverse effects than the MnO NPs and the clinically used GDI GBCAs, providing useful information on future applications of ESIONs as potentially safe MRI contrast agents.

Dynamic Contrast-enhanced MR Lymphangiography: Feasibility Study in Swine

To demonstrate the feasibility of dynamic four-dimensional ( 4D four-dimensional ) intranodal contrast material-enhanced magnetic resonance (MR) lymphangiography with inguinal lymph node injection of gadopentetate dimeglumine. All procedures were performed in accordance with the guidelines on the use of animals in research and were approved by the animal care and use committee. Five swine underwent nonenhanced MR lymphangiography with a heavily T2-weighted MR sequence, bilateral inguinal lymph node injection of 2 mL of undiluted gadopentetate at a rate of 1 mL/min, and 60 minutes of MR imaging with T1-weighted high-spatial- and high-temporal-resolution MR angiography. Images were reviewed by a radiologist with expertise in lymphatic imaging and a pediatric cardiac MR imaging specialist for visualization of the thoracic duct ( TD thoracic duct ). Categorical variables were compared by using the exact conditional McNemar test. A difference with a P value less than .05 was considered significant. The TD thoracic duct was visualized in three of the five animals (60%) on T2-weighted images. In contrast, the TD thoracic duct was visualized in all five of the animals (100%) after contrast agent injection (P = .25). The median time for flow of the contrast agent through the lymphatic system to the TD thoracic duct outlet was 244 seconds (range, 201-387 seconds). Enhancement was seen in the TD thoracic duct up to 1 hour after injection. All animals survived without any complications. Dynamic 4D four-dimensional contrast-enhanced MR lymphangiography with intranodal injection of gadopentetate dimeglumine is feasible, produces good images of the central lymphatic system, and demonstrates the time course of flow of contrast agent up the central lymphatic ducts. On the basis of the results of this initial animal experiment, it appears that dynamic 4D four-dimensional contrast-enhanced MR lymphangiography is potentially feasible and safe with commercially available contrast agents.

Absolute values of late enhancement volume is superior to percentage of late enhancement volume per total LV myocardium volume to predict MACE in hypertrophic cardiomyopathy: a CMR Study

Purpose: To determine a useful predictor of major adverse cardiac events (MACE) in patients with hypertrophic cardiomyopathy (HCM), we compared focal late enhancement (LE) volume (LEV) in the left ventricular myocardium (LVM) to the percentage of LEV per total LVM volume (TLVMV) (%LEV/TLVMV) by cardiac magnetic resonance (CMR), and followed subjects for a median of 16 months. Methods: Fifty-five consecutive HCM subjects (33 males, mean age 62.5±13.6 years) undergoing CMR (1.5T Intra achieva, Philips) were recruited. CMR was acquired at 15 min after injection of Gadopentetate dimeglumine for detecting LEV in LVM quantitatively. Areas with signal-intensity ≥ mean+2SD of signal-intensity of remote normal LVM were regarded as LE. LEV was measured by the threshold method (Ziostation 2, Zio). Result: LE in LVM was detected in 46 subjects, and LEV and %LEV/TLVMV were 35.4±27.1cm3 and 25.0±19.2%, respectively. Ten subjects (18%) had MACE. According to Receiver Operating Characteristic (ROC) curves, at a cutoff of 45.6cm3 (LEV) and 23.8% (%LEV/TLVMV), the sensitivity and specificity of LEV for MACE detection were 80% and 75%, respectively (Area under curve (AUC) 0.766) and those of %LEV/TLVMV were 100% and 59% (AUC 0.811), respectively. HCM subjects were divided into groups on the basis of 1) LEV ≥ and <45.6cm3 and (2) %LEV/TLVMV ≥ and <23.8%. Significant differences between Group 1 and Group 2 subjects were observed on Kaplan Meier analysis and log rank test (both P<0.01). On Cox proportional hazard models, the hazard ratios for the occurrence of MACE were 8.08 (LEV, P=0.008) and 60.8 (%LEV/TLVMV, P=0.118), and only the former was significant. ![Figure][1] ROC curves Conclusion: Both LEV and %LEV/TLVMV by CMR may be useful to predict the risk of MACE in HCM subjects, and LEV is superior to %LEV/TLVMV. [1]: pending:yes

Comparison of look-locker and MOLLI sequences for T1 mapping in hypertrophic and ischemic cardiomyopathy

Methods 5 control patients (4M/1F, age 44±21 y) with normal left ventricular (LV) function and no history of heart disease, 5 patients with ICM (3M/2F, 63±2 y), and 16 patients with HCM (10M/6F, age 51±15y) were recruited into an IRB approved protocol. All subjects were imaged at 1.5T (Achieva XR, Philips). T1 mapping was performed using MOLLI and LL at 2 LV short axis levels (basaland midcavity) before and after contrast agent injection (Magnevist; 0.2 mmol/kg). Post gadopentetate dimeglumine (Magnevist; 0.2 mmol/kg) injection time was about 15 min for HCM and ICM patients and was shorter (about 5 min) for the controls due to organizational reasons. For each subject, TI measurements were made in 6 ROIs per level.

Detection of post operative residual cholesteatoma using PROPELLER DWI combined with conventional MRI

Objective: The aim of this study is to determine the role of PROPELLER diffusion-weighted MR imaging combined with conventional MR imaging for the detection of residual cholesteatoma in patients who have undergone middle ear surgery.Subjects and methods: Twenty patients who had undergone resection of cholesteatoma were referred for MR imaging. MR imaging (1.5T) was performed using a PROPELLER DWI, T2WI, FLAIR and T1WI before and after IV injection of gadopentetate dimeglumine. An experienced reviewer evaluated the diffusion-weighted MR images for the presence of a high-signal-intensity and calculated corresponding ADC values. Imaging findings were correlated with findings from surgery in 14 patients and with findings from clinical follow-up examination in six patients.Results: Diffusion-weighted MR imaging combined with conventional MR imaging depicted eight cholesteatomas. Two lesions were missed that were <3mm. One patient was misdiagnosed as cholesteatoma, biopsy revealed acute inflammation. Sensitivity was 80%, specificity was 90%, positive predictive value was 89% and negative predictive value was 82%.Conclusion: Diffusion-weighted MR imaging combined with conventional MRI and calculation of ADC values is useful in the detection of secondary cholesteatoma and would decrease the need for un-necessary second canal wall-up operation.

MR Lymphangiography at 3.0 T: Correlation with Lymphoscintigraphy

To prospectively compare findings of magnetic resonance (MR) lymphangiography with those of lymphoscintigraphy, evaluate the pattern and delay of lymphatic drainage, compare typical findings, and investigate discrepancies between the techniques. This prospective study was performed according to the Declaration of Helsinki and was approved by the local ethics committee. Thirty consecutive patients with uni- or bilateral lymphedema and lymph vessel transplants of the lower extremities were examined with 3.0-T fat-saturated three-dimensional gradient-echo MR after gadopentetate dimeglumine injection. Results of all examinations were correlated with corresponding results of lymphoscintigraphy examinations. Results of both techniques were separately reviewed in consensus by a radiologist and a nuclear physician, who rated delay and pattern of drainage, number of enhancing levels, and quality of conspicuity of the depiction of lymph nodes and lymph vessels. Sensitivity and specificity were calculated by using combined results of both techniques and clinical presentation findings as reference standard. Correlation was calculated with weighted k coefficients. Weak lymphatic drainage at lymphoscintigraphy correlated with lymphangiectasia at MR lymphangiography (13 of 33 affected extremities). Lymph vessels were clearly visualized with MR lymphangiography (five of 24 affected extremities), while they were not detectable with lymphoscintigraphy. Depiction of inguinal lymph nodes was clearer with lymphoscintigraphy (five of 60 extremities). Correlation of both techniques was excellent for delay (κ=0.93) and pattern (κ=0.84) of drainage, good for depiction of lymph nodes (κ=0.67) and number of enhancing levels (κ=0.77), and moderate for depiction of lymph vessels (κ=0.50). Sensitivity and specificity for delay and pattern of drainage were concordant, whereas MR lymphangiography showed a higher sensitivity for lymph vessel abnormalities (100% vs 79%) and lower specificity for lymph node abnormalities (78% vs 100%). Imaging findings of MR lymphangiography and lymphoscintigraphy show a clear concordance. With lymphoscintigraphy, better visualization of inguinal lymph nodes was achieved, whereas with MR lymphangiography, better depiction of lymph vessels and morphologic features of lymph vessel abnormalities were achieved.

Peripheral Arterial Wall Imaging Using Contrast-Enhanced, Susceptibility-Weighted Phase Imaging

To demonstrate improved delineation of peripheral arterial wall in susceptibility-weighted imaging (SWI) phase images by using gadolinium contrast agent. Superficial femoral arteries were imaged using high-resolution SWI in 11 healthy volunteers before and after injection of gadopentetate dimeglumine. Two postcontrast scans started 1 minute and 11 minutes after injection, respectively. Eight of the 11 volunteers also underwent double-inversion recovery turbo-spin-echo (TSE) scans. The same resolution and matrix size were used between SWI and TSE studies, and TSE locations were matched to SWI images. Arterial lumen-wall phase difference and phase contrast-to-noise ratio were measured and compared between precontrast and postcontrast SWI measurements. The lumen and wall areas measured on both TSE and matching SWI images were analyzed for agreement. Two other volunteers participated in a double-echo gradient-echo study. Results were compared to SWI. By injecting gadolinium contrast agent, phase difference changed by 54.5% and -1.6%, and phase contrast-to-noise ratio changed by 85.7% and 27.0% for the first and second postcontrast scans, respectively. Morphological measurements showed insignificant difference between TSE and SWIs based on paired t tests; good agreements in Bland-Altman plots were achieved. The double-echo gradient-echo study had similar phase measurements as SWI. Contrast-enhanced phase imaging improves arterial wall delineation in SWI of peripheral arterial wall. Contrast-enhanced SWI is a promising vessel wall imaging technique.

Shoulder MR Arthrography: Intraarticular Anesthetic Reduces Periprocedural Pain and Major Motion Artifacts but Does Not Decrease Imaging Time

To prospectively determine whether the addition of an intraarticular anesthetic to the magnetic resonance (MR) arthrography solution has an effect on periprocedural pain, motion artifacts, and imaging time. This study was approved by the institutional review board, and written informed consent was obtained from all patients. From September 2009 to March 2010, 127 patients, most imaged for shoulder pain, were randomized into two groups. The first group (group A, 63 patients) received intraarticular injection of gadopentetate dimeglumine, ropivacaine 0.5%, and normal saline in a ratio of 1:100:100. The second group (group B, 64 patients) received intraarticular injection of gadopentetate dimeglumine and normal saline in a ratio of 1:200. Pain was assessed before and after injection and immediately after 1.5-T MR imaging and rated on a scale of 0 to 10. Motion artifact was assessed by two musculoskeletal radiologists and two fellows by using a scale of 0 to 3 (0=no artifact, 1=artifact present but not affecting diagnostic image quality, 2=artifact present and diminishing diagnostic image quality, and 3=artifact present and rendering image nondiagnostic). MR imaging time and examinations with repeated sequences were recorded. Wilcoxon rank sum, analysis of covariance, and permutation data analyses were performed. The mean pain levels before injection, after injection, and after MR imaging were 3.5, 2.3, and 2.5, respectively, for group A and 3.6, 3.1, and 3.2 for group B. After adjusting for age, sex, and preinjection pain level, the mean differences in pre- and postinjection pain and preinjection pain and post-MR imaging pain between the two groups were -0.9 (P=.017) and -0.8 (P=.056), respectively. No significant difference in mean total MR imaging time or number of patients with repeat sequences was noted. Radiologists 1 and 2 recorded grade 2 or 3 motion in six and five patients, respectively, in group A and 15 and 14 patients, respectively, in group B (P=.047 and .048, respectively). Radiologists 3 and 4 recorded grade 2 or 3 motion in 13 and 23 patients, respectively, in group A and 23 and 33 patients, respectively, in group B (P=.093 and .110, respectively). The use of an intraarticular anesthetic significantly reduces periprocedural pain and major motion artifacts associated with MR shoulder arthrography; however, total MR imaging time is not reduced.

Small Animal Look-Locker Inversion Recovery (SALLI) for Simultaneous Generation of Cardiac T1 Maps and Cine and Inversion Recovery–prepared Images at High Heart Rates: Initial Experience

To develop a single magnetic resonance (MR) imaging approach for comprehensive assessment of cardiac function and tissue properties in small animals with high heart rates. All animal studies were approved by the local animal care committee. Small animal Look-Locker inversion recovery (SALLI) was implemented on a clinical 3.0-T MR unit equipped with a 70-mm solenoid coil. SALLI combines a segmented, electrocardiographically gated, inversion recovery-prepared Look-Locker-type pulse sequence with a multimodal reconstruction framework. Temporal undersampling and radial nonbalanced steady-state free precession enabled acceleration of data acquisition and reduction of motion artifacts, respectively. Nine agarose gel phantoms were used to investigate different sequence settings. For in vivo studies, 10 Sprague-Dawley rats were evaluated to establish normal T1 values before and after injection of gadopentetate dimeglumine. Seven rats with surgically induced acute myocardial infarction were examined to test the feasibility of detecting myocardial injury. In vitro T1 behavior was studied with linear regression analysis, and in vivo T1 differences between infarcted and remote areas were tested by using the Wilcoxon signed rank test. Phantom studies demonstrated systematic behavior of the T1 measurements, and T1 error could be reduced to 1.3% ± 7.4 by using a simple linear correction algorithm. The pre- and postcontrast T1 of myocardium and blood showed narrow normal ranges. In the area of infarction, SALLI demonstrated hypokinesia (on cine images), myocardial edema (on precontrast T1 maps), and myocardial necrosis (on postcontrast T1 maps and late gadolinium enhancement images). An MR imaging method enabling simultaneous generation of cardiac T1 maps and cine and inversion recovery-prepared images at high heart rates is presented. SALLI allows for simultaneous and time-efficient assessment of cardiac T1 behavior, function, and late gadolinium enhancement at high heart rates.

Solitary necrotic nodule of the liver: MR findings in 33 pathologically proved lesions

To determine characteristic magnetic resonance (MR) imaging features of solitary necrotic nodule of the liver. MR images features of thirty-two patients (17 men, 15 women; mean age, 43 years; range, 24-76 years) with pathologically proved solitary necrotic nodule of the liver were retrospectively analyzed for number, size, signal intensity features and enhancement patterns. A total of 33 lesions were identified. The mean diameter was 2.3cm (range 1.0-4.5cm). Thirty lesions (90.9%) were 1.0-3.0cm in diameter and only 3 lesions (9.1%) were larger than 3.0cm. On T1-weighted images, solitary necrotic nodule of the liver appeared hypointense in 31 lesions (93.9%) and isointense in 2 lesions (6.1%). On T2-weighted images, 12 (36.4%) lesions were hyperintense, 15 (45.4%) were isointense or invisible and 6 (18.2%) were hypointense. After injection of gadopentetate dimeglumine, all lesions were hypointense and none of them showed enhancement. Solitary necrotic nodule of the liver is usually small with the size not exceed 3.0cm in diameter. Absence of enhancement on all dynamic phase after gadopentetate dimeglumine administration may be most characteristic feature of solitary necrotic nodule of the liver on MR images, which may help discriminate this entity from metastatic liver tumors and intrahepatic cholangiocarcinoma.

Detection of Coronary Artery Anomalies in Infants and Young Children with Congenital Heart Disease by Using MR Imaging

To evaluate the feasibility and accuracy of magnetic resonance (MR) coronary angiography for the detection of coronary artery anomalies in infants and children by using surgical findings as a reference. The data analysis was approved by the institutional review board. One hundred children with congenital heart disease underwent MR coronary angiography while under general anesthesia (mean age ± standard deviation, 3.9 years ± 3; age range, 0.2-11 years). A navigator-gated, T2-prepared, three-dimensional steady-state free precession whole-heart protocol (isotropic voxel size, 1.0-1.3 mm(3); mean imaging time, 4.6 minutes ± 1.2; mean navigator efficiency, 70%; 3-mm gating window) was used after injection of gadopentetate dimeglumine. The cardiac rest period (end systole or middiastole) and acquisition window were prospectively assessed for each patient. Coronary artery image quality (score of 0 [nondiagnostic] to 4 [excellent]), vessel sharpness, and coronary artery anomalies were assessed by two observers. Surgery was performed in 58 patients, and those findings were used to define accuracy. Variables were assessed between age groups by using either analysis of variance or Kruskal-Wallis tests. Diagnostic image quality (score, ≥1 for all coronary artery segments) was obtained in 46 of the 58 patients (79%) who underwent surgery. The origin and course of the coronary artery anatomy depicted with MR imaging was confirmed at surgery in all 46 patients-including the four (9%) with substantial coronary artery anomalies. Diagnostic-quality images were obtained in 84 of the 100 patients. The rate of success improved significantly when patients were older than 4 months (88% for patients >4 months vs 17% for patients ≤4 months, P < .001). Improved whole-heart MR coronary angiography enables accurate detection of abnormal origin and course of the coronary artery system even in very young patients with congenital heart disease.