Estimation and Analysis of Wave Spectrum Parameter using HeMOSU-2 Observation Data

In this study, wave spectrum data were calculated using the water surface elevation data observed at 5Hz intervals from the HeMOSU-2 meteorological tower installed on the west coast of Korea, and wave parameters were estimated using wave spectrum data. For all significant wave height ranges, the peak enhancement parameter (γ opt ) of the JONSWAP spectrum and the scale parameter (α) and shape parameter (β) of the modify BM spectrum were estimated based on the observed spectrum, and the distribution of each parameter was confirmed. As a result of the analysis, the peak enhancement parameter (γ opt ) of the JONSWAP spectrum was calculated to be 1.27, which is very low compared to the previously proposed 3.3. And in the range of all significant wave heights, the distribution of the peak enhancement parameter (γ opt ) was shown as a combined distribution of probability mass function (PMF) and probability density function (PDF). In addition, the scale parameter (α) and shape parameter (β) of the modify BM spectrum were estimated to be [0.245, β1.278], which are lower than the existing [0.300, -1.098], and the result of the linear correlation analysis between the two parameters was β = =3.86α.

Effect of decreased contrast injection flow rate on aortic enhancement in 80-KV peak CT with contrast dose reduction

Background Effect of decreased injection flow rate of contrast agent at the same iodine dose and delivery rate on aortic enhancement has not been clearly elucidated. Purpose To evaluate the effect of decreased injection flow rate of contrast agent on aortic peak enhancement in a dynamic flow phantom and on aortic enhancement in clinical dynamic 80-kVp computed tomography (CT) with contrast dose reduction. Material and Methods In the dynamic flow phantom experiment, the effect of a decreased injection flow rate at the same total iodine dose and delivery rate on simulated aortic peak enhancement was evaluated. In the clinical retrospective study, we searched 312 patients with renal dysfunction who underwent an 80-kVp abdominal dynamic CT with 40% reduction of contrast agent from a standard 120-kVp protocol and measured the aortic enhancement at the level of the hepatic hilum. Independent predictors for aortic enhancement were determined by multiple linear regression analysis, and after adjustment of significant predictors, independent variables for acquiring optimal aortic enhancement, ≥300 HU, were determined by multiple logistic regression analysis. Results In the phantom experiment, decreased flow rate showed a significant but small descent effect (6%–9%) on simulated aortic peak enhancement. In the multiple linear regression analysis, only age was an independent predictor of aortic enhancement; there was no independent predictor for optimal age-adjusted aortic enhancement of ≥300 HU. Conclusions Decreased injection flow rate had a small influence on aortic enhancement in vitro but had no significant effect on the aortic enhancement in clinical dynamic 80-kVp CT.

Application of Multislice Spiral CT Imaging Technology in the Diagnosis of Patients with Chest Sarcoidosis

Objective. To study the qualitative value of multislice spiral CT (MSCT) dynamic enhancement scanning for solitary nodules (SPN) of the chest. Methods. In this paper, 40 cases of chest nodules (including 25 cases of malignant nodules, 8 cases of inflammatory nodules, and 7 cases of benign nodules) were first scanned to determine the scope of nodules. At the two rates of 5 ml/s and 3 ml/s, CT dynamic enhancement scans were performed at the center of the nodule, and the CT values, peak enhancement (PH) and peak time (PT) before and after SPN enhancement, were recorded. It is mainly strengthened, with 80% (20/25) of net added value between 20 and 60 Hu, and 20% (5/25) >60 Hu or <20 Hu. The enhancement peak and peak time are (31.31 ± 10.62) Hu and 45 s, respectively. The time-density curve (T-DC) showed a slowly rising type; the inflammatory nodules were mainly severely strengthened, with a net increase of >40 Hu. The enhancement peak value is (49.25 ± 12.44) Hu, and the peak time is 80 s and 140 s. There is a characteristic of rising and falling and then rising in the curve. Conclusion. Multislice spiral CT dynamic enhancement scan reflects the dynamic characteristics of chest nodular blood flow, which can be used to noninvasively evaluate and diagnose SPN.

Exploring the parameter space of modified supergravity for double inflation and primordial black hole formation

We study the parameter space of the effective (with two scalars) models of cosmological inflation and primordial black hole (PBH) formation in the modified (R+ R 2) supergravity. Our models describe double inflation, whose first stage is driven by Starobinsky’s scalaron coming from the R 2 gravity, and whose second stage is driven by another scalar belonging to the supergravity multiplet. The ultra-slow-roll regime between the two stages leads a large peak (enhancement) in the power spectrum of scalar perturbations, which results in efficient PBH formation. Both inflation and PBH formation are generic in our models, while those PBH can account for a significant part or the whole of dark matter. Some of the earlier proposed models in the same class are in tension (over 3σ) with the observed value of the scalar tilt ns , so that we study more general models with more parameters, and investigate the dependence of the cosmological tilts (ns,r) and the scalar power spectrum enhancement upon the parameters. The PBH masses and their density fraction (as part of dark matter) are also calculated. A good agreement (between 2σ and 3σ) with the observed value of ns requires fine tuning of the parameters, and it is only realized in the so-called δ-models. Our models offer the (super)gravitational origin of inflation, PBH and dark matter together, and may be confirmed or falsified by future precision measurements of the cosmic microwave background radiation and PBH-induced gravitational waves.

Dynamic contrast-enhanced magnetic resonance imaging of the lung reveals important pathobiology in idiopathic pulmonary fibrosis

IntroductionEvidence suggest that abnormalities occur in the lung microvasculature in idiopathic pulmonary fibrosis (IPF). We hypothesized that dynamic contrast-enhanced (DCE)-MRI could detect alterations in permeability, perfusion, and extracellular extravascular volume in idiopathic pulmonary fibrosis thus providing in vivo regional functional information not otherwise available.MethodsHealthy controls and IPF subjects underwent DCE-MRI of the thorax using a dynamic volumetric radial sampling sequence and administration of gadoterate meglumine at a dose of 0.1 mmol·kg−1 at 2 mL·s−1. Model-free analysis of signal intensity versus time curves in regions of interest from a lower, middle, and upper axial plane and a posterior coronal plane yielded parameters reflective of perfusion and permeability (peak enhancement and rate of contrast arrival, kwashin) and the extracellular extravascular space (rate of contrast clearance, kwashout). These imaging parameters were compared between IPF and healthy control subjects, and between fast/slow IPF progressors.ResultsIPF subjects (n=16, M=56%, age=67.5 (range 60–79)) had significantly reduced peak enhancement and slower kwashin in all measured lung regions compared to the healthy volunteers (n=17, M=65%, age=58 (range 51–63)) on unadjusted analyses consistent with microvascular alterations. kwashout, as a measure of the extravascular extracellular space, was significantly slower in the lower lung and posterior coronal regions in the IPF subjects consistent with an increased extravascular extracellular space. All estimates were attenuated after adjusting for age. Similar trends were observed, but only the associations with kwashin remained statistically significant. Among IPF subjects, kwashout rates nearly perfectly discriminated between those with rapidly progressive disease versus those with stable/slowly progressive disease.ConclusionsDCE-MRI detects changes in the microvasculature and extravascular extracellular space in IPF thus providing in vivo regional functional information.

Hydralazine augmented ultrasound hyperthermia for the treatment of hepatocellular carcinoma

This study investigates the use of hydralazine to enhance ultrasound hyperthermia for the treatment of hepatocellular carcinoma (HCC) by minimizing flow-mediated heat loss from the tumor. Murine HCC tumors were treated with a continuous mode ultrasound with or without an intravenous administration of hydralazine (5 mg/kg). Tumor blood flow and blood vessels were evaluated by contrast-enhanced ultrasound (CEUS) imaging and histology, respectively. Hydralazine markedly enhanced ultrasound hyperthermia through the disruption of tumor blood flow in HCC. Ultrasound treatment with hydralazine significantly reduced peak enhancement (PE), perfusion index (PI), and area under the curve (AUC) of the CEUS time-intensity curves by 91.9 ± 0.9%, 95.7 ± 0.7%, and 96.6 ± 0.5%, compared to 71.4 ± 1.9%, 84.7 ± 1.1%, and 85.6 ± 0.7% respectively without hydralazine. Tumor temperature measurements showed that the cumulative thermal dose delivered by ultrasound treatment with hydralazine (170.8 ± 11.8 min) was significantly higher than that without hydralazine (137.7 ± 10.7 min). Histological assessment of the ultrasound-treated tumors showed that hydralazine injection formed larger hemorrhagic pools and increased tumor vessel dilation consistent with CEUS observations illustrating the augmentation of hyperthermic effects by hydralazine. In conclusion, we demonstrated that ultrasound hyperthermia can be enhanced significantly by hydralazine in murine HCC tumors by modulating tumor blood flow. Future studies demonstrating the safety of the combined use of ultrasound and hydralazine would enable the clinical translation of the proposed technique.

Renal Artery Pseudo-aneurysms: Do All of Them Require Endovascular Management?

Purpose: Our study examines the etiological profile, clinical and imaging features of renal artery pseudo aneurysms (RAPs), as well as the efficacy and need for the angioembolization of RAPs in a resource-constrained setting. Materials and Methods: A total of 36 patients with RAPs were included in our study. Initial diagnosis was made by Doppler Ultrasonography (USG) followed by CT renal angiography in all cases. DSA was performed in 28 patients, as eight patients showed spontaneous resolution by thrombosis on immediate pre-procedure Doppler study. Angioembolization with a microcoil was performed for 30 aneurysms in 28 patients. Technical success was confirmed at the end of the procedure by a renal angiogram. To assess clinical success, we followed up with patients (with clinical and Doppler USG) for a period of six months. Results: The most common cause of RAPs in our study was percutaneous nephrolithotomy (PCNL), seen in 21 patients (58.3%), followed by trauma (25%), and partial nephrectomy (11%). All patients presented to us were within 21 days of the etiological event of hematuria or flank pain. USG was able to detect the RAP in 22 cases (61%). CT renal angiography was diagnostic in all patients but failed to demonstrate two additional aneurysms in one patient. RAP size ≤ 4 mm and absence of brisk filling on CT renal angiography was associated with spontaneous resolution in eight patients, probably an indication of the beginning of spontaneous thrombosis. Angioembolization was done using microcoils and showed 100% technical and clinical success. Conclusion: PCNL is the most common etiological factor for RAPs in our setting. Such patients should have a Doppler USG done prior to discharge from the hospital. CT angiographic flow dynamics (delayed peak enhancement) may be helpful in the identification of RAPs with a high probability of subsequent spontaneous resolution. Angiography followed by embolization using microcoils is the most effective and safe treatment for RAPs with no significant loss of renal parenchyma, although cost remains a limiting factor in our setting.

Applicability of B-mode ultrasonography, ARFI elastography and contrast-enhanced ultrasound in the evaluation of chronic kidney disease in dogs

ABSTRACT: The objective of this study was to verify the applicability of B-mode ultrasonography, ARFI elastography and CEUS in the diagnosis of chronic kidney disease and its Stages in dogs. 24 healthy dogs and 28 with CKD were included. In B-mode, the echogenicity, echotexture and cortico-medullary ratio of the kidneys were verified. By elastography, the shear-wave velocity of the cortical (SWVcort) and medullary (SWVmed) regions were determined and tissue deformity was evaluated. Wash-in, wash-out and peak enhancement (TPic) of the contrast in the renal parenchyma were calculated and homogeneity, presence of filling gaps and distinction of filling phases were evaluated by CEUS. Changes in echogenicity, echotexture and cortico-medullary ratio were observed only in sick patients. There was an increase in SWVcort in CKD, with a cutoff point >2.91m/s. Healthy kidneys were non-deformable and 25% had changes in gray scales. There was an increase in wash-in and TPic, changes in filling characteristics, filling failures and difficulty in distinguishing between the Stages in CEUS in CKD. It was found that dogs with CKD 2, 3 and 4 had greater SWVcort and wash-in values than CKD 1. Elastographic and CEUS changes were observed in dogs with CKD, demonstrating the applicability of ultrasonographic techniques in their diagnosis.

Can Enhancement Pattern and Enhancement Level on Biphasic Enhanced CT Distinguish Homogeneous Pheochromocytomas From Adenomas Without Lipid

Objective The purpose of our study was to evaluate whether enhancement pattern and enhancement level on biphasic enhanced CT can distinguish homogeneous pheochromocytomas from adenomas without lipid and explore the value of percentage of peak enhancement (PPE) in differentiating the two entities.Methods We retrospectively analysed pathologically proven 17 pheochromocytomas and 34 adenomas. Both tumors were homogeneous without necro-cystic changes and hemorrhage. The inclusion criteria for adenomas without lipid in our study was that the mean attenuation values were greater than 10 HU and the minimum values were greater than 0 HU on unenhanced CT. Biphasic CT scan protocol consisted of unenhanced phase, arterial phase (25-35 seconds) and venous phase (60-80 seconds). The enhancement pattern, attenuation values on unenhanced and enhanced phases and PPE were compared between the two groups.Results Enhancement pattern was similar between the two groups (p>0.99), persistent enhancement pattern on venous phase was the most common in both tumors. The precontrast CT values of pheochromocytomas were significantly higher than that of adenomas without lipid (41 HU vs 37 HU, p=0.006). The enhancement level on arterial and venous phase of pheochromocytomas was greater than that of adenomas without lipid, but no significant differences were found (100 HU vs 85 HU, p=0.223; 103 HU vs 96 HU, p=0.905, respectively). The distribution of PPE of two entities was different. A range of 100%-240% of PPE can discriminate adenomas without lipid from pheochromocytomas, with sensitivity of 88.2%, specificity of 47.1%. Conclusion The enhancement pattern and enhancement level on biphasic enhanced CT could not distinguish homogeneous pheochromocytomas from adenomas without lipid. Further studies are needed to prove the potential value of PPE due to its low specificity.