1.
Low-Dose Scanning Technology Combined with Low-Concentration Contrast Material in Renal Computed Tomography Angiography (CTA): A Preliminary Study.
Liu, S, Li, W, Shi, H, Sheng, H, Fan, J, He, J, Sun, H
Medical science monitor : international medical journal of experimental and clinical research. 2017;:4351-4359
Abstract
BACKGROUND This study is to investigate the feasibility of low iodine concentration contrast material (CM) combined with low tube voltage and adaptive statistical iterative reconstruction (ASIR) in renal computed tomography angiography (CTA). MATERIAL AND METHODS A total of 136 patients were enrolled in this prospective trial, and randomly divided into two groups: group A (n=68) and group B (n=68). Group A received 120-kVp and iopromide (370 mg/mL) with filtered back projection (FBP) reconstruction, and group B received 100-kVp and iodixanol (270 mg/mL) with ASIR 40% (ASIR40). An equal iodine dose (300 mg/kg body weight) and the same iodine delivery rate (1,500 mg I/s) were given to all patients. Density, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured, and the image quality and visualization of renal arteries were scored. Dose-length product (DLP) and CT dose index volume (CTDIvol) were recorded, and effective doses (ED) were calculated. RESULTS There was no significant difference in image noise between groups A and B (p>0.05). The vessel attenuation, SNR, and CNR were significantly higher in group B than group A (all p<0.05). The subjective image quality and visualization of renal artery branches were similar in these two groups (p>0.05). Compared with group A, the CTDIvol, DLP, and ED in group B were decreased by 38.58%, 37.24%, and 37.24%, respectively (p=0.000). CONCLUSIONS Compared with 120-kVp with FBP reconstruction, the protocol of 100-kVp with ASIRP40 reconstruction provided high-quality renal CTA results, which allowed for reduced iodine concentration and decreased radiation dose.
2.
Labeling human embryonic stem-cell-derived cardiomyocytes for tracking with MR imaging.
Castaneda, RT, Boddington, S, Henning, TD, Wendland, M, Mandrussow, L, Liu, S, Daldrup-Link, H
Pediatric radiology. 2011;(11):1384-92
Abstract
BACKGROUND Human embryonic stem cells (hESC) can generate cardiomyocytes (CM), which offer promising treatments for cardiomyopathies in children. However, challenges for clinical translation result from loss of transplanted cell from target sites and high cell death. An imaging technique that noninvasively and repetitively monitors transplanted hESC-CM could guide improvements in transplantation techniques and advance therapies. OBJECTIVE To develop a clinically applicable labeling technique for hESC-CM with FDA-approved superparamagnetic iron oxide nanoparticles (SPIO) by examining labeling before and after CM differentiation. MATERIALS AND METHODS Triplicates of hESC were labeled by simple incubation with 50 μg/ml of ferumoxides before or after differentiation into CM, then imaged on a 7T MR scanner using a T2-weighted multi-echo spin-echo sequence. Viability, iron uptake and T2-relaxation times were compared between groups using t-tests. RESULTS hESC-CM labeled before differentiation demonstrated significant MR effects, iron uptake and preserved function. hESC-CM labeled after differentiation showed no significant iron uptake or change in MR signal (P < 0.05). Morphology, differentiation and viability were consistent between experimental groups. CONCLUSION hESC-CM should be labeled prior to CM differentiation to achieve a significant MR signal. This technique permits monitoring delivery and engraftment of hESC-CM for potential advancements of stem cell-based therapies in the reconstitution of damaged myocardium.