Dataset Information

USPIO-enhanced MRI of pelvic lymph nodes at 7-T: preliminary experience.

ABSTRACT: PURPOSE:To evaluate the technical feasibility of high-resolution USPIO-enhanced magnetic resonance imaging of pelvic lymph nodes (LNs) at ultrahigh magnetic field strength. MATERIALS AND METHODS:The ethics review board approved this study and written informed consent was obtained from all patients. Three patients with rectal cancer and three selected patients with (recurrent) prostate cancer were examined at 7-T 24-36 h after intravenous ferumoxtran-10 administration; rectal cancer patients also received a 3-T MRI. Pelvic LN imaging was performed using the TIAMO technique in combination with water-selective multi-GRE imaging and lipid-selective GRE imaging with a spatial resolution of 0.66?×?0.66?×?0.66mm3. T2*-weighted images of the water-selective imaging were computed from the multi-GRE images at TE?=?0, 8, and 14 ms and used for the assessment of USPIO uptake. RESULTS:High-resolution 7-T MR gradient-echo imaging was obtained robustly in all patients without suffering from RF-related signal voids. USPIO signal decay in LNs was visualized using computed TE imaging at TE?=?8 ms and an R2* map derived from water-selective imaging. Anatomically, LNs were identified on a combined reading of computed TE?=?0 ms images from water-selective scans and images from lipid-selective scans. A range of 3-48 LNs without USPIO signal decay was found per patient. These LNs showed high signal intensity on computed TE?=?8 and 14 ms imaging and low R2* (corresponding to high T2*) values on the R2* map. CONCLUSION:USPIO-enhanced MRI of the pelvis at 7-T is technically feasible and offers opportunities for detecting USPIO uptake in normal-sized LNs, due to its high intrinsic signal-to-noise ratio and spatial resolution. KEY POINTS:• USPIO-enhanced MRI at 7-T can indicate USPIO uptake in lymph nodes based on computed TE images. • Our method promises a high spatial resolution for pelvic lymph node imaging.

SUBMITTER: Philips BWJ

PROVIDER: S-EPMC6828641 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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USPIO-enhanced MRI of pelvic lymph nodes at 7-T: preliminary experience.

Philips Bart W J BWJ Stijns Rutger C H RCH Rietsch Stefan H G SHG Brunheim Sascha S Barentsz Jelle O JO Fortuin Ansje S AS Quick Harald H HH Orzada Stephan S Maas Marnix C MC Scheenen Tom W J TWJ

European radiology 20190614 12

<h4>Purpose</h4>To evaluate the technical feasibility of high-resolution USPIO-enhanced magnetic resonance imaging of pelvic lymph nodes (LNs) at ultrahigh magnetic field strength.<h4>Materials and methods</h4>The ethics review board approved this study and written informed consent was obtained from all patients. Three patients with rectal cancer and three selected patients with (recurrent) prostate cancer were examined at 7-T 24-36 h after intravenous ferumoxtran-10 administration; rectal cance ...[more]

PMID: 31201525

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Project description:The composition of lymph nodes in pediatric patients is different from that in adults. Most notably, normal lymph nodes in children contain less macrophages. Therefore, previously described biodistributions of iron oxide nanoparticles in benign and malignant lymph nodes of adult patients may not apply to children. The purpose of our study was to evaluate if the iron supplement ferumoxytol improves the differentiation of benign and malignant lymph nodes in pediatric cancer patients on 18F-FDG PET/MRI. Methods: We conducted a prospective clinical trial from May 2015 to December 2018 to investigate the value of ferumoxytol nanoparticles for staging of children with cancer with 18F-FDG PET/MRI. Ferumoxytol is an FDA-approved iron supplement for the treatment of anemia and has been used "off-label" as an MRI contrast agent in this study. Forty-two children (7-18 years, 29 male, 13 female) received a 18F-FDG PET/MRI at 2 (n=20) or 24 hours (h) (n=22) after intravenous injection of ferumoxytol (dose 5 mg Fe/kg). The morphology of benign and malignant lymph nodes on ferumoxytol-enhanced T2-FSE sequences at 2 and 24 h were compared using a linear regression analysis. In addition, ADCmean-values, SUV-ratio (SUVmax lesion/SUVmean liver) and R2*-relaxation rate of benign and malignant lymph nodes were compared with a Mann-Whitney-U test. The accuracy of different criteria was assessed with a receiver operating characteristics (ROC) curve. Follow-up imaging for at least 6 months served as the standard of reference. Results: We examined a total of 613 lymph nodes, of which 464 (75.7%) were benign and 149 (24.3%) were malignant. On ferumoxytol-enhanced T2-FSE images, benign lymph nodes showed a hypointense hilum and hyperintense parenchyma, while malignant lymph nodes showed no discernible hilum. This pattern was not significantly different at 2 h and 24 h postcontrast (p=0.82). Benign and malignant lymph nodes showed significantly different ferumoxytol enhancement patterns, ADCmean values of 1578 and 852 x10-6 mm2/s, mean SUV-ratios of 0.5 and 2.8, and mean R2*-relaxation rate of 127.8 and 84.4 Hertz (Hz), respectively (all p<0.001). The accuracy of ADCmean, SUV-ratio and pattern (area under the curve (AUC): 0.99; 0.98; 0.97, respectively) was not significantly different (p=0.07). Compared to these three parameters, the accuracy of R2* was significantly lower (AUC: 0.93; p=0.001). Conclusion: Lymph nodes in children show different ferumoxytol-enhancement patterns on MRI than previously reported for adult patients. We found high accuracy (>90%) of ADCmean, SUV-ratio, pattern, and R2* measurements for the characterization of benign and malignant lymph nodes in children. Ferumoxytol nanoparticle accumulation at the hilum can be used to diagnose a benign lymph node. In the future, the delivery of clinically applicable nanoparticles to the hilum of benign lymph nodes could be harnessed to deliver theranostic drugs for immune cell priming.

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Dataset Information

USPIO-enhanced MRI of pelvic lymph nodes at 7-T: preliminary experience.

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USPIO-enhanced MRI of pelvic lymph nodes at 7-T: preliminary experience.

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