[Evaluation of Detectability in Clinical Practice of Metal Detectors, etc. for Magnetic Resonance Imaging].

PURPOSE: In order to prevent magnetic materials from being brought into the magnetic resonance imaging (MRI) examination room, many facilities have metal detectors, etc., but there are various types of equipment with different performance and characteristics. The purpose of this study was to evaluate each detector in actual clinical practice. METHODS: At multiple facilities, gate-type magnetic detectors, pole-type magnetic detectors, handy-type magnetic detectors, and handy-type metal detectors were used to identify 9 types of objects that may be brought into the MRI examination room. We performed evaluation of detection distance measurement assuming actual operation. RESULTS: The gate type was only able to detect objects with strong magnetism. With the pole type, the closer the measurement distance was to the pole, the more objects could be detected, and the lower the pole, the shorter the detection distance. With the handy type, there were many objects that could be detected when the device and the object were brought into close contact. CONCLUSION: The detectability of the instruments varied depending on the size and type of the object. It is important to understand the characteristics of each device and use it according to the purpose in carrying-in confirmation before the examination.

Predictivity of acute kidney injury risk scores for late kidney injury in patients with chronic coronary syndrome.

Late rather than acute kidney injury after percutaneous coronary intervention (PCI) has been recently recognized as a predictor of future adverse events in patient with coronary artery disease. The risk-predicting models for acute kidney injury reported by Mehran et al., Bartholomew et al., and Tsai et al. were derived from a large cohort and externally validated, although the applicability of these models for predicting late kidney injury is unknown. A total of 327 patients undergoing elective PCI procedures were included. We calculated the three scores and tested their diagnostic ability for predicting late kidney injury (> 6 months after PCI), defined as an increase in creatinine levels ≥ 0.3 mg/dl or ≥ 50% from baseline. During the median follow-up period of 28 months, 27 (8.3%) patients had late kidney injury. All three scores significantly predicted late kidney injury, among which the score by Tsai et al. had a better diagnostic ability (area under the curve 0.83, best cut-off value 14, p < 0.001). With the best cut-off value, patients with Tsai score ≥ 14 had a significantly higher rate of late kidney injury than their counterpart (27.4% vs. 2.8%, p < 0.001). In conclusion, established risk scores for acute kidney injury may be useful for predicting late kidney injury after PCI in patients with chronic coronary syndrome.

Combination of compressed sensing and parallel imaging for T2-weighted imaging of the oral cavity in healthy volunteers: comparison with parallel imaging.

OBJECTIVE: Compressed sensing (CS) and parallel imaging (PI) are magnetic resonance (MR) imaging acceleration techniques. Image quality of two-dimensional fast spin echo imaging of the oral cavity using CS or combined CS and PI has not been evaluated. The aim of this study was to compare the acquisition time and image quality between T2-weighted imaging (T2WI) with CS and PI (CSPI-T2WI) and T2WI with PI (PI-T2WI) of the oral cavity. MATERIALS AND METHODS: Twenty healthy volunteers who underwent CSPI-T2WI and PI-T2WI of the oral cavity on a 3 T MR scanner were enrolled in the study. Contrast ratios of fat/muscle and bone/muscle on CSPI-T2WI and PI-T2WI were measured. Overall image quality, 4 kinds of artifacts, and visualization of 18 anatomical structures were independently evaluated by two radiologists with grading scales. The quantitative and qualitative measurements were compared between CSPI-T2WI and PI-T2WI by using the Wilcoxon signed-rank test. RESULTS: Mean acquisition time of CSPI-T2WI and PI-T2WI was 72 s and 136 s, respectively (p < .001). CSPI-T2WI showed a significantly higher contrast ratio of fat/muscle than PI-T2WI (p < .01). There were no significant differences in the overall image quality, artifacts, and visualization of anatomical structures between CSPI-T2WI and PI-T2WI. CONCLUSIONS: CSPI-T2WI of the oral cavity in healthy volunteers can provide a reduction in acquisition time without impaired image quality compared to PI-T2WI. KEY POINTS: • The acquisition time of T2WI with the combined CS and PI provided a 47% reduction in acquisition time compared with T2WI with PI. • T2WI with the combined CS and PI did not show impaired image quality compared with T2WI with PI. • Combined CS and PI can be a useful technology to evaluate the oral cavity with high-speed acquisition.

Trajectory of renal function change and kidney injury after percutaneous coronary intervention in patients with stable coronary artery disease.

Acute kidney injury usually assessed within 48 h after percutaneous coronary intervention (PCI) is associated with poor clinical outcomes, and persistent kidney damage is also strongly related to long-term mortality. However, little is known about longitudinal renal function change from a very early period to long-term follow-up after PCI. A total of 327 patients with stable coronary artery disease underwent elective PCI. Renal function was assessed with serum creatinine levels and estimated glomerular filtration rate (eGFR) at baseline, 1 day after PCI, at 1 year and at the latest follow-up. Kidney injury was defined as an increase in creatinine levels ≥ 0.3 mg/dl or ≥ 50% from baseline at each timepoint. Major adverse cardiovascular events (MACE) was defined as a composite of death, myocardial infarction, and stroke. eGFR was significantly increased 1 day after PCI, while it was progressively decreased at 1-year and long-term follow-up (median 28 months). Overall, eGFR was declined by - 2.3 ml/min/1.73 m2 per year. Only one (0.3%) patient developed kidney injury 1 day after PCI, whereas kidney injury at 1-year and long-term follow-up was observed in 15 (4.6%) and 27 (8.3%). During the follow-up period, 23 (7.0%) patients had MACE. The incidence of subsequent MACE was significantly higher in patients with kidney injury at 1 year than those without. In conclusion, kidney injury within 24 h after elective PCI was rarely observed. eGFR was progressively decreased over time, and mid-term kidney injury at 1 year was associated with future MACE.

Reversible water uptake/release by thermoresponsive polyelectrolyte hydrogels derived from ionic liquids.

Thermoresponsive polyelectrolyte hydrogels, derived from tetra-n-alkylphosphonium 3-sulfopropyl methacrylate-type ionic liquid monomers, show reversible water uptake/release, in which the gels absorb/desorb water for at least ten cycles via a lower critical solution temperature-type phase transition.

Ionic liquid-derived charged polymers to show highly thermoresponsive LCST-type transition with water at desired temperatures.

A polymerised ionic liquid (poly(IL)) having suitable hydrophobicity undergoes a strongly temperature-sensitive LCST-type phase transition with pure water and also with aqueous salt solution, and the resulting hydrated poly(IL) further undergoes a sharp and reversible liquid-to-gel transition at ambient temperatures.