UNASSIGNED: Non-contrast T1-weighted imaging (T1WI) with cardiac magnetic resonance enables to evaluate the intensity of coronary plaque. Plaque-to-myocardial signal intensity ratio (PMR) has been shown to associate with an elevated risk of future coronary events. Of note, PMR >1.4 is a best cut-off value to identify high-risk plaque causing future coronary events. One recent study has reported intraluminal thrombus as a contributor to PMR. However, whether plaque material itself is associated with PMR has not been fully characterized yet. We present three cases with coronary artery stenosis evaluated by non-contrast T1WI-magnetic resonance imaging, optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS)-intravascular ultrasound (IVUS) imaging.
UNASSIGNED: Case 1 exhibited one lesion with high PMR (2.79) at the proximal segment of left anterior descending (LAD) artery. OCT imaging did not identify any obvious intra-luminal thrombus but the presence of lipid-rich plaque harboring cholesterol crystal at the corresponding lesion. In addition, an elevated maximum 4-mm lipid-core burden index (maxLCBI4mm) (=873) was observed at this lesion by NIRS/IVUS imaging. In case 2, PMR of coronary stenosis at the middle segment of LAD artery was 1.88. This lesion harboured lipidic materials without any thrombus on OCT imaging. NIRS-derived maxLCBI4mm was 725. Case 3 had a severe stenosis at the middle segment of LAD artery. This lesion exhibited a low PMR (0.90). On OCT and NIRS/IVUS imaging, this lesion was characterized as the presence of small lipid arc with a low maxLCBI4mm (=386).
UNASSIGNED: These cases showed the possible relationship of T1WI-derived PMR with the degree of lipidic plaque components.

Near-infrared spectroscopy (NIRS) is a non-invasive clinical tool allowing for real-time, continuous measurement of regional tissue oxygenation (rSO2); though predominantly used for neuromonitoring, it also has the potential for early detection of hemodynamic compromise in the patients on extracorporeal life support (ECLS). The authors present two cases of neonates for whom continuous monitoring of multisite rSO2 with NIRS provided the first indication of a significant compromise in hemodynamic status from catastrophic hemorrhagic complications while on ECLS ahead of conventional ECLS monitoring parameters. Routine NIRS monitoring of neonates on ECLS has utility for ongoing assessment of hemodynamic status and can be used for early detection of complications leading to impaired tissue perfusion.

UNASSIGNED: Tissue oedema affects tissue perfusion and interferes with the monitoring of tissue oxygenation in patients with severe sepsis. However, the underlying mechanisms remain unclear. We used a wireless near-infrared spectroscopy (NIRS) device that transmits tri-wavelength light to quantify tissue haemoglobin (Hb) and water (H2O) content. We estimated tissue H2O in severe sepsis patients and healthy controls, compared their difference, and investigated the correlation of tissue H2O with systemic haemodynamics and its impact on tissue oxygenation.
UNASSIGNED: Seventy-seven adult patients with new-onset severe sepsis admitted to the intensive care unit within 72 h and 30 healthy volunteers (controls) were enrolled. The NIRS device was placed on the participant\'s leg to estimate the relative tissue concentrations of oxy-Hb ([HbO2]), deoxy-Hb ([HbR]), total Hb ([HbT]), and H2O ([H2O]) at rest for three consecutive days. Two-sample t-test or Mann-Whitney U test, chi-square test, and generalised estimating equations (GEEs) were used for comparisons.
UNASSIGNED: In severe sepsis patients, the [H2O] in the anterior tibia was higher [mean (standard deviation, 95% confidence interval), 10.57 (3.37, 9.81-11.34) vs. 7.40 (1.89, 6.70-8.11)] and the [HbO2], [HbT], and tissue Hb oxygen saturation (StO2) were lower [0.20 (0.01, 0.20-0.20) vs. 0.22 (0.01, 0.22-0.23), 0.42 (0.02, 0.42-0.43) vs. 0.44 (0.02, 0.44-0.45), and 47.25% (1.97%, 46.80-47.70%) vs. 49.88% (1.26%, 49.41-50.35%), respectively] than in healthy controls in first-day measurements. GEE analysis revealed significant differences in [H2O], [HbO2], [HbT], and StO2 between groups over three consecutive days (all P≤0.001). In addition, [HbO2] and StO2 levels gradually decreased over time in the patient group. A negative correlation was observed between [H2O] and [HbO2] and StO2, which became more obvious over time (day 1: r=-0.51 and r=-0.42, respectively; both P<0.01; day 3: r=-0.67 and r=-0.63, respectively, both P<0.01). Systolic arterial pressure was positively related to [H2O] (r=0.51, P<0.05, on day 1) but was not associated with tissue oxygenation parameters.
UNASSIGNED: NIRS can be used to quantify tissue H2O. Severe sepsis patients have increased tissue H2O, which responds to changes in arterial blood pressure and affects tissue oxygenation.