Does quantification of USPIO uptake‐related signal loss allow differentiation of benign and malignant normal‐sized pelvic lymph nodes?

Abstract

Ultrasmall superparamagnetic iron oxide (USPIO) particles are promising contrast media, especially for molecular and cellular imaging besides lymph node staging owing to their superior NMR efficacy, macrophage uptake and lymphotropic properties. The goal of the present prospective clinical work was to validate quantification of signal decrease on high-resolution T(2)-weighted MR sequences before and 24-36 h after USPIO administration for accurate differentiation between benign and malignant normal-sized pelvic lymph nodes. Fifty-eight patients with bladder or prostate cancer were examined on a 3 T MR unit and their respective lymph node signal intensities (SI), signal-to-noise (SNR) and contrast-to-noise (CNR) were determined on pre- and post-contrast 3D T(2)-weighted turbo spin echo (TSE) images. Based on histology and/or localization, USPIO-uptake-related SI/SNR decrease of benign vs malignant and pelvic vs inguinal lymph nodes was compared. Out of 2182 resected lymph nodes 366 were selected for MRI post-processing. Benign pelvic lymph nodes showed a significantly higher SI/SNR decrease compared with malignant nodes (p < 0.0001). Inguinal lymph nodes in comparison to pelvic lymph nodes presented a reduced SI/SNR decrease (p < 0.0001). CNR did not differ significantly between benign and malignant lymph nodes. The receiver operating curve analysis yielded an area under the curve of 0.96, and the point with optimal accuracy was found at a threshold value of 13.5% SNR decrease. Overlap of SI and SNR changes between benign and malignant lymph nodes were attributed to partial voluming, lipomatosis, histiocytosis or focal lymphoreticular hyperplasia. USPIO-enhanced MRI improves the diagnostic ability of lymph node staging in normal-sized lymph nodes, although some overlap of SI/SNR-changes remained. Quantification of USPIO-dependent SNR decrease will enable the validation of this promising technique with the final goal of improving and individualizing patient care.

Dual-modular molecular imaging to trace transplanted bone mesenchymal stromal cells in an acute myocardial infarction model

“…At day 3, a distinct hypointense region was observed in the anterior wall of the heart, which was in agreement with the results of BLI tracing and histological localization. Clinically, MRI tracking of USPIO-labeled cells is yet to be carried out in a cardiovascular setting but has been used successfully in stroke [17] and cancer [18].…”

Non-invasive In-Vivo Imaging of Stem Cells after Transplantation in Cardiovascular Tissue

“…Treatment was safe and the labeled cells were tracked for 3 weeks. USPIO particles have been used with success in clinical settings as an MRI contrast in patients with stroke 43 and for sentinel node identification in cancer patients 44,45.…”

A comprehensive literatures update of clinical researches of superparamagnetic resonance iron oxide nanoparticles for magnetic resonance imaging

“…Fortuin et al (87) pointed that the diagnostic performance of that study can be improved by using T2* based sequence, and also interpreter's experience is of crucial importance, which may also impact the impact of these agents on daily practice (and their market access), since the learning curve may be long. It is expected experienced readers and standardized evaluation protocol would have led to a better outcome (88). Ferumoxytol, like other SPIO agents, is not cleared by glomerular filtration but by macrophages in the RES, and this feature could also serve to help detect pathology in the RES where normal uptake is not observed, such as in the diagnosis of metastatic lymphadenopathy.…”