I n the 30 years since gadolinium-based contrast agents (GBCAs) were first introduced to enhance MRI (1), their adoption into routine clinical practice has been prolific. Worldwide, more than 450 million doses of GBCAs have been administered and have yielded indispensable diagnostic information in virtually every organ system (2). The safety profile of GBCAs was relatively unblemished until their association with nephrogenic systemic fibrosis in 2006 (3). Clinical practice patterns were altered rapidly, and judicious use or avoidance of GBCAs in patients with
PurposeTo summarize our single‐center safety experience with the off‐label use of ferumoxytol for magnetic resonance imaging (MRI) and to compare the effects of ferumoxytol on monitored physiologic indices in patients under anesthesia with those of gadofosveset trisodium.Materials and MethodsConsecutive patients who underwent ferumoxytol‐enhanced (FE) MRI exams were included. Adverse events (AEs) were classified according to the Common Terminology Criteria for Adverse Events v4.0. In a subgroup of patients examined under general anesthesia, recording of blood pressure, heart rate, oxygen saturation, and end‐tidal CO2 was performed. A comparable group of 23 patients who underwent gadofosveset‐enhanced (GE) MRI under anesthesia with similar monitoring was also analyzed.ResultsIn all, 217 unique patients, ages 3 days to 94 years, underwent FE‐MRI. No ferumoxytol‐related severe, life‐threatening, or fatal AEs occurred acutely or at follow‐up. Two patients developed ferumoxytol‐related nausea. Between‐group (FE‐ vs. GE‐MRI) comparisons showed no statistical difference in heart rate (P = 0.69, 95% confidence interval [CI] 96–113 bpm), mean arterial blood pressure (MAP) (P = 0.74, 95% CI 44–52 mmHg), oxygen saturation (P = 0.76, 95% CI 94–98%), and end‐tidal CO2 (P = 0.73, 95% CI 31–37 mmHg). No significant change in MAP (P = 0.12, 95% CI 50–58 mmHg) or heart rate (P = 0.25, 95% CI 91–105 bpm) was noted between slow infusion of ferumoxytol (n = 113) vs. bolus injection (n = 104).ConclusionIn our single‐center experience, no serious AEs occurred with the diagnostic use of ferumoxytol across a wide spectrum of age, renal function, and indications. Because of the limited sample size, firm conclusions cannot be drawn about the generalizability of our results. Thus, vigilance and monitoring are recommended to mitigate potential rare adverse reactions. Level of Evidence: 2J. Magn. Reson. Imaging 2017;45:804–812.
Purpose To assess the technical feasibility of the use of ferumoxytol-enhanced (FE) magnetic resonance (MR) angiography for vascular mapping before transcatheter aortic valve replacement in patients with renal impairment. Materials and Methods This was an institutional review board-approved and HIPAA-compliant study. FE MR angiography was performed at 3.0 T or 1.5 T. Unenhanced computed tomographic (CT) images were used to overlay vascular calcification on FE MR angiographic images as composite fused three-dimensional data. Image quality of the subclavian and aortoiliofemoral arterial tree and confidence in the assessment of calcification were evaluated by using a four-point scale (4 = excellent vascular definition or strong confidence). Signal intensity nonuniformity as reflected by the heterogeneity index (ratio between the mean standard deviation of luminal signal intensity and the mean luminal signal intensity), signal-to-noise ratio, and consistency of luminal diameter measurements were quantified. Findings at FE MR angiography were compared with pelvic angiograms. Results Twenty-six patients underwent FE MR angiography without adverse events. A total of 286 named vascular segments were scored. The image quality score was 4 for 99% (283 of 286) of the segments (κ = 0.9). There was moderate to strong confidence in the ability to assess vascular calcific morphology in all studies with complementary unenhanced CT. The steady-state luminal heterogeneity index was low, and signal-to-noise ratio was high. Interobserver luminal measurements were reliable (intraclass correlation coefficient, 0.98; 95% confidence interval: 0.98, 0.99). FE MR angiographic findings were consistent with correlative pelvic angiograms in all 16 patients for whom the latter were available. Conclusion In patients with renal impairment undergoing transcatheter aortic valve replacement, FE MR angiography is technically feasible and offers reliable vascular mapping without exposure to iodine- or gadolinium-based contrast agents. Thus, the total cumulative dose of iodine-based contrast material is minimized and the risk of acute nephropathy is reduced. RSNA, 2017 Online supplemental material is available for this article.
BackgroundBright-blood and black-blood cardiovascular magnetic resonance (CMR) techniques are frequently employed together during a clinical exam because of their complementary features. While valuable, existing black-blood CMR approaches are flow dependent and prone to failure. We aim to assess the effectiveness and reliability of ferumoxytol enhanced (FE) Half-Fourier Single-shot Turbo Spin-echo (HASTE) imaging without magnetization preparation pulses to yield uniform intra-luminal blood signal suppression by comparing FE-HASTE with pre-ferumoxytol HASTE imaging.MethodsThis study was IRB-approved and HIPAA compliant. Consecutive patients who were referred for FE-CMR between June 2013 and February 2017 were enrolled. Qualitative image scores reflecting the degree and reliability of blood signal suppression were based on a 3-point Likert scale, with 3 reflecting perfect suppression. For quantitative evaluation, homogeneity indices (defined as standard deviation of the left atrial signal intensity) and signal-to-noise ratios (SNR) for vascular lumens and cardiac chambers were measured.ResultsOf the 340 unique patients who underwent FE-CMR, HASTE was performed in 257. Ninety-three patients had both pre-ferumoxytol HASTE and FE-HASTE, and were included in this analysis. Qualitative image scores reflecting the degree and reliability of blood signal suppression were significantly higher for FE-HASTE images (2.9 [IQR 2.8–3.0] vs 1.8 [IQR 1.6–2.1], p < 0.001). Inter-reader agreement was moderate (k = 0.50, 95% CI 0.45–0.55). Blood signal suppression was more complete on FE-HASTE images than on pre-ferumoxytol HASTE, as indicated by lower mean homogeneity indices (24.5 [IQR 18.0–32.8] vs 108.0 [IQR 65.0–170.4], p < 0.001) and lower blood pool SNR for all regions (5.6 [IQR 3.2–10.0] vs 21.5 [IQR 12.5–39.4], p < 0.001).ConclusionFE-HASTE black-blood imaging offers an effective, reliable, and simple approach for flow independent blood signal suppression. The technique holds promise as a fast and routine complement to bright-blood cardiovascular imaging with ferumoxytol.Electronic supplementary materialThe online version of this article (10.1186/s12968-017-0422-y) contains supplementary material, which is available to authorized users.
BackgroundAlthough cardiovascular magnetic resonance venography (CMRV) is generally regarded as the technique of choice for imaging the central veins, conventional CMRV is not ideal. Gadolinium-based contrast agents (GBCA) are less suited to steady state venous imaging than to first pass arterial imaging and they may be contraindicated in patients with renal impairment where evaluation of venous anatomy is frequently required. We aim to evaluate the diagnostic performance of 3-dimensional (3D) ferumoxytol-enhanced CMRV (FE-CMRV) for suspected central venous occlusion in patients with renal failure and to assess its clinical impact on patient management.MethodsIn this IRB-approved and HIPAA-compliant study, 52 consecutive adult patients (47 years, IQR 32–61; 29 male) with renal impairment and suspected venous occlusion underwent FE-CMRV, following infusion of ferumoxytol. Breath-held, high resolution, 3D steady state FE-CMRV was performed through the chest, abdomen and pelvis. Two blinded reviewers independently scored twenty-one named venous segments for quality and patency. Correlative catheter venography in 14 patients was used as the reference standard for diagnostic accuracy. Retrospective chart review was conducted to determine clinical impact of FE-CMRV. Interobserver agreement was determined using Gwet’s AC1 statistic.ResultsAll patients underwent technically successful FE-CMRV without any adverse events. 99.5% (1033/1038) of venous segments were of diagnostic quality (score ≥ 2/4) with very good interobserver agreement (AC1 = 0.91). Interobserver agreement for venous occlusion was also very good (AC1 = 0.93). The overall accuracy of FE-CMRV compared to catheter venography was perfect (100.0%). No additional imaging was required prior to a clinical management decision in any of the 52 patients. Twenty-four successful and uncomplicated venous interventions were carried out following pre-procedural vascular mapping with FE-CMRV.Conclusions3D FE-CMRV is a practical, accurate and robust technique for high-resolution mapping of central thoracic, abdominal and pelvic veins and can be used to inform image-guided therapy. It may play a pivotal role in the care of patients in whom conventional contrast agents may be contraindicated or ineffective.Electronic supplementary materialThe online version of this article (10.1186/s12968-019-0528-5) contains supplementary material, which is available to authorized users.
Purpose Develop a novel three‐dimensional (3D) generative adversarial network (GAN)‐based technique for simultaneous image reconstruction and respiratory motion compensation of 4D MRI. Our goal was to enable high‐acceleration factors 10.7X‐15.8X, while maintaining robust and diagnostic image quality superior to state‐of‐the‐art self‐gating (SG) compressed sensing wavelet (CS‐WV) reconstruction at lower acceleration factors 3.5X‐7.9X. Methods Our GAN was trained based on pixel‐wise content loss functions, adversarial loss function, and a novel data‐driven temporal aware loss function to maintain anatomical accuracy and temporal coherence. Besides image reconstruction, our network also performs respiratory motion compensation for free‐breathing scans. A novel progressive growing‐based strategy was adapted to make the training process possible for the proposed GAN‐based structure. The proposed method was developed and thoroughly evaluated qualitatively and quantitatively based on 3D cardiac cine data from 42 patients. Results Our proposed method achieved significantly better scores in general image quality and image artifacts at 10.7X‐15.8X acceleration than the SG CS‐WV approach at 3.5X‐7.9X acceleration (4.53 ± 0.540 vs. 3.13 ± 0.681 for general image quality, 4.12 ± 0.429 vs. 2.97 ± 0.434 for image artifacts, P < .05 for both). No spurious anatomical structures were observed in our images. The proposed method enabled similar cardiac‐function quantification as conventional SG CS‐WV. The proposed method achieved faster central processing unit‐based image reconstruction (6 s/cardiac phase) than the SG CS‐WV (312 s/cardiac phase). Conclusion The proposed method showed promising potential for high‐resolution (1 mm3) free‐breathing 4D MR data acquisition with simultaneous respiratory motion compensation and fast reconstruction time.
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