[Effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy for screening imported patients with COVID-19 in Xiamen]

Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.

Enhanced Anti-Tumor Activity in Mice with Temozolomide-Resistant Human Glioblastoma Cell Line-Derived Xenograft Using SN-38-Incorporated Polymeric Microparticle

Glioblastoma multiforme (GBM) has remained one of the most lethal and challenging cancers to treat. Previous studies have shown encouraging results when irinotecan was used in combination with temozolomide (TMZ) for treating GBM. However, irinotecan has a narrow therapeutic index: a slight dose increase in irinotecan can induce toxicities that outweigh its therapeutic benefits. SN-38 is the active metabolite of irinotecan that accounts for both its anti-tumor efficacy and toxicity. In our previous paper, we showed that SN-38 embedded into 50:50 biodegradable poly[(d,l)-lactide-co-glycolide] (PLGA) microparticles (SMPs) provides an efficient delivery and sustained release of SN-38 from SMPs in the brain tissues of rats. These properties of SMPs give them potential for therapeutic application due to their high efficacy and low toxicity. In this study, we tested the anti-tumor activity of SMP-based interstitial chemotherapy combined with TMZ using TMZ-resistant human glioblastoma cell line-derived xenograft models. Our data suggest that treatment in which SMPs are combined with TMZ reduces tumor growth and extends survival in mice bearing xenograft tumors derived from both TMZ-resistant and TMZ-sensitive human glioblastoma cell lines. Our findings demonstrate that combining SMPs with TMZ may have potential as a promising strategy for the treatment of GBM.

A simple method for moving source depth estimation applied to the SWellEx96 data

Existing methods for source localization in an ocean waveguide generally require simultaneous range and depth estimation as they are intrinsically coupled in the acoustic field. Using beam intensities averaged over ranges longer than the mode cycle distances, it is shown that the range-averaged vertical beam distribution is insensitive to the source range and sensitive to the source depth. An incoherent matched beam processing method is presented and applied to the SWellEx96 moving source data to estimate source depth based on the 127 and 130 Hz signals with good results.

Beam-time delay domain deconvolved scheme for high-resolution active localization of underwater targets

Matched filter (MF) and conventional beamforming (CBF) are widely used in active sonar; the performance of the former (temporal resolution) is limited by the signal bandwidth, and that of the latter (angular resolution) is limited by the array aperture. Previous work has shown that angular resolution can be significantly improved by deconvolving the CBF outputs. In this paper, deconvolution is extended to the time domain by deconvolving the MF outputs, and a high-resolution two-dimensional deconvolution method is proposed to simultaneously improve the temporal and angular resolution. Numerical simulations and experimental tank data show that angular resolutions are improved 26 times, and temporal resolutions are improved 10 times compared with the conventional MF and CBF methods. Reverberations are much suppressed to allow target echoes to be detected from the received time series data.

Deconvolution of decomposed conventional beamforming

A recently proposed deconvolution method applied to conventional beamforming (CBF) shows a much higher array gain (AG) than CBF in theory, thereby providing the possibility for detecting a weak signal with a much lower signal-to-noise ratio (SNR). However, simulated data processing shows an effective AG that decreases with decreasing SNR. The reason for the performance loss is analyzed. A method based on deconvolution of the signal subspace of the CBF outputs is shown to recover most of the AG loss. It is used to trace a weak signal in bearing and time.

Matched beam-intensity processing for a deep vertical line array

A vertical line array can be deployed in deep water below the critical depth, the depth where the sound speed equals the sound speed at the surface, to take advantage of the lower ambient noise level (compared with above the critical depth) for target detection. To differentiate a submerged source from a surface source, a Fourier transform based method [McCargar and Zurk, J. Acoust. Soc. Am. 133, EL320-325 (2013)] was proposed for a narrowband signal that exploits the depth-related harmonic (oscillation) feature of the beam power time series associated with the target arrival. In this paper, incoherent matched beam processing is used to estimate the target depth. Where the replica (calculated) beam intensity or amplitude time series best matches that of the data is used to estimate the source depth. This method is shown, based on simulated data, to provide a better depth resolution in general and better ability to estimate the depth of a very shallow source (say at 10 m) and can be used to complement the Fourier transform based method. It can be extended to process (random) broadband signals and to environments where the Lloyd's mirror theory is not valid.

Injectable SN-38-embedded Polymeric Microparticles Promote Antitumor Efficacy against Malignant Glioma in an Animal Model

Malignant glioma (MG) is extremely aggressive and highly resistant to chemotherapeutic agents. Using electrospraying, the potent chemotherapeutic agent 7-ethyl-10-hydroxycamptothecia (SN-38) was embedded into 50:50 biodegradable poly[(d,l)-lactide-co-glycolide] (PLGA) microparticles (SMPs). The SMPs were stereotactically injected into the brain parenchyma of healthy rats and intratumorally injected into F98 glioma-bearing rats for estimating the pharmacodynamics and therapeutic efficacy. SN-38 was rapidly released after injection and its local (brain tissue) concentration remained much higher than that in the blood for more than 8 weeks. Glioma-bearing rats were divided into three groups—group A (n = 13; stereotactically injected pure PLGA microparticles), group B (n = 12; stereotactically injected Gliadel wafer and oral temozolomide), and group C (n = 13; stereotactic and intratumoral introduction of SMPs). The SMPs exhibited significant therapeutic efficacy, with prolonged survival, retarded tumor growth, and attenuated malignancy. The experimental results demonstrated that SMPs provide an effective and potential strategy for the treatment of MG.

Joint towed array shape and direction of arrivals estimation using sparse Bayesian learning during maneuvering

Large aperture towed arrays are widely used underwater to detect weak targets. During maneuvering, the beamformer performance degrades significantly if a wrong array configuration is assumed. Currently, engineering sensors and/or (augmented) acoustic sources are used to estimate the array element positions. The results are often inadequate depending on the number of measurements available. In this paper, an adaptive bow (AB) sparse Bayesian learning (SBL) algorithm is proposed, called ABSBL. Assuming the towed array follows a parabola shape during slow turns and treating the array bow as a hyperparameter in SBL, the bow and directions of arrival (DOAs) of the signals can be jointly estimated from the received acoustic data. Simulations show that ABSBL yields accurate estimates of the bow and target DOAs if the turning direction is known. ABSBL is applied to the MAPEX2000 data. The estimated array bow and DOA agrees with that estimated from relative time delays measured from acoustic pings and SBL, better than that estimated from the GPS data using the water-pulley model. The method can potentially be applied without engineering sensors.

Channel distortion on target scattering amplitude in shallow water

Bistatic acoustic scattering uses echo returns from a target to estimate the scattered intensity or amplitude as a function of angle and frequency (acoustic color) for target classification. In a shallow water waveguide, the echo return from a target at a distance, such as a mine, is modified by the waveguide and deviates significantly from that at close range or in free space. The channel effect or distortion on the echo return is studied using simulated data. A simple frequency domain signal processing method is proposed to equalize the channel effect. The frequency and angle distribution of the estimated scattering function is compared with that of the original function. It is found to be an adequate representation of the original function with a high correlation coefficient (∼0.88).

Source localization in range-dependent and time-varying shallow water: The Shallow Water 2006 experimental results

In a range-dependent and time-varying environment, such as at the Shallow Water 2006 (SW06) experimental site, matched field processing often has difficulty localizing a moving source emitting a narrowband signal when signal mismatch is difficult to mitigate given only the nominal sound speed profile and bottom properties along the source track. Based on the range-averaged mode wavenumbers and depth functions estimated from data received on a vertical line array by synthetic beamforming (without any environmental information) using Doppler shift as a reference, a method is proposed in this paper to search for the source depth first and then the source range. Source localization is demonstrated with the SW06 data for two source runs along and oblique to the shelf. Robustness is achieved by minimizing/breaking the coupling between range and depth, when one of them can be estimated using non-environment-related input.

Brain computerized tomography reading in suspected acute ischemic stroke patients: what are essentials for medical students?

BACKGROUND

Few systematic methods prioritize the image education in medical students (MS). We hope to develop a checklist of brain computerized tomography (CT) reading in patients with suspected acute ischemic stroke (AIS) for MS and primary care (PC) physicians.

METHODS

Our pilot group generated the items indicating specific structures or signs for the checklist of brain CT reading in suspected AIS patients for MS and PC physicians. These items were used in a modified web-based Delphi process using the online software "SurveyMonkey". In total 15 panelists including neurologists, neurosurgeons, neuroradiologists, and emergency department physicians participated in the modified Delphi process. Each panelist was encouraged to express feedback, agreement or disagreement on the inclusion of each item using a 9-point Likert scale. Items with median scores of 7-9 were included in our final checklist.

RESULTS

Fifty-two items were initially provided for the first round of the Delphi process. Of these, 35 achieved general agreement of being an essential item for the MS and PC physicians. The other 17 of the 52 items in this round and another two added items suggested by the panelists were further rated in the next round. Finally, 38 items were included in the essential checklist items of brain CT reading in suspected AIS patients for MS and PC physicians.

CONCLUSIONS

We established a reference regarding the essential items of brain CT reading in suspected AIS patients. We hope this helps to minimize malpractice and a delayed diagnosis, and to improve competency-based medical education for MS and PC physicians.

Array gain of coprime arrays

A coprime array of M + N - 1 elements is designed, using product processing (PP), to yield the same beam width as that of a full array of MN elements using conventional beamforming (CBF), while at the same time suppressing the grating lobes. The array gain (AG) for isotropic noise using conventional PP is slightly less than that obtained using CBF, namely, 10log(M + N - 1). It is shown that using the coherent product processing, the coprime array yields an AG equal to that of the full array of MN elements, 10log(MN). The superior gain is often referred to as supergain.

Superdirective beamforming applied to SWellEx96 horizontal arrays data for source localization

Arrays employing superdirective beamforming can provide the same directivity and directivity index (or array gain) with less aperture as a large size array using conventional beamforming (CBF). Superdirective arrays offer a practical and significant improvement in the reception of low frequency signals and is useful for many applications where the array size is limited, such as a miniature microphone array or an underwater acoustic array with a limited aperture. Deconvolving the CBF is a method of superdirective beamforming. The improvement in directivity (beam width) and array gain is studied/illustrated using the SWellEx96 horizontal array data where only sub-arrays are used.

The association between body mass index, primary healthcare use and morbidity in early childhood: findings from the Born In Bradford cohort study

OBJECTIVES

The objective of the article was to examine the association between body mass index (BMI), health and general practice (GP) healthcare use in early childhood.

STUDY DESIGN

This study is a prospective cohort study.

METHODS

Multivariate Poisson and logistic regression models were used to explore the association between BMI and health outcomes using data from the Born In Bradford cohort study, linked to routine data capturing objective measures of BMI at age 5 years, alongside GP appointment rates, GP prescriptions and specific morbidities in the subsequent 3-year period.

RESULTS

Compared with healthy weight, children who were obese at the age of 5 years had significantly higher rates of GP appointments (incident rate ratio 1.14, 95% confidence interval [CI]: 1.06-1.23), GP prescriptions (incident rate ratio 1.15, 95% CI: 1.04-1.27), asthma (odds ratio 1.46, 95% CI: 1.21-1.77), sleep apnoea (odds ratio 2.50, 95% CI: 1.36-4.58), infections (incident rate ratio 1.19, 95% CI: 1.08-1.30), antibiotic prescriptions (incident rate ratio 1.25, 95% CI: 1.10-1.42) and accidents (incident rate ratio 1.20, 95% CI: 1.01-1.42) in the subsequent 3 years. Underweight children were found to have higher rates of GP appointments (incident rate ratio 1.25, 95% CI: 1.04-1.52), but there were no differences between overweight and healthy weight children.

CONCLUSIONS

Childhood obesity was found to be associated with increased primary healthcare use and a range of poorer health outcomes at the age of 8 years, underlining the importance of reducing childhood obesity in early childhood.

Probable pathogenesis, diagnosis, and management of untreated arteriovenous malformation with cyst formation: case report and literature review

Arteriovenous malformations (AVMs) usually manifest as headaches, seizures, focal neurological signs, and spontaneous intracerebral or subarachnoid hemorrhages. An untreated AVM with associated cyst formation is extremely rare, and the probable pathogenesis is unclear. We propose and discuss the possible pathogenesis of this condition and its diagnosis and management. A 26-year-old male presented with a generalized tonic-clonic seizure. Computed tomography showed a cystic lesion in the left frontal lobe and magnetic resonance imaging revealed a complex composition within the lesion, without a flow-voiding signal. Therefore, the initial diagnosis was oligodendroglioma and surgical treatment was performed. However, intraoperatively, engorged reddish nodule-like vessels with a cystic capsule and intra-cyst brown and sticky fluid were found. The nodule-like vessels and cystic capsule were resected completely. The patient's postoperative course was uneventful, with an excellent neurological outcome and no further seizures. Pathological examination of the surgical specimen revealed the typical microscopic appearance of an AVM, with numerous thin-walled vascular channels and deposits of hemosiderin in fibrous tissue. In conclusion, an untreated AVM with associated cyst formation is extremely rare, and the mechanism of formation is unclear. We propose a probable pathogenesis. Preoperative diagnosis, intraoperative management, and postoperative follow-up are equally crucial in dealing with this extremely rare condition. Cystic tumors associated with arteriovenous malformations (AVMs) are uncommon and are usually a complication of stereotactic radiosurgery (Ilyas et al. in J Neurosurg. https://doi.org/10.3171/2016.12.JNS162478 , 2017) or form after a hemorrhage (Daniels et al. in Radiology 133:393-394, 1979). Untreated AVMs with large cysts or cystic tumors are rare, with only five cases reported in the literature (Table 1). Here, we present a case of an untreated AVM associated with cystic formation, or a cystic tumor, in the left frontal lobe.

Heterozygous FUT1 Mutations Causing a Para-Bombay Phenotype

BACKGROUND

To study a case of para-Bombay phenotype caused by compound heterozygous mutation of the FUT1 gene.

METHODS

We performed an agglutination examination to anti-H serum. Secretor status was determined in order to assess the presence of soluble blood group substances. Genotyping of ABO and FUT1 genes were also performed.

RESULTS

Our results showed the presence of A and H antigens in the saliva. Based on these results, the patient in the present case was diagnosed to have a para-Bombay A phenotype. Direct DNA sequencing of the patient's ABO gene indicated A1v/O1vgenotype. FUT1 gene sequence analysis revealed that the patient harbored the compound heterozygous mutations c.881_882delTT (p.Phe294Cysfs) and c.551_552delAG (p.Glu184Valfs).

CONCLUSIONS

In summary, our findings support that the occurrence of a heterozygous mutation in FUT1, 547delAG/880delTT, is the most common mutation in Taiwanese.

Physics-based coastal current tomographic tracking using a Kalman filter

Ocean acoustic tomography can be used based on measurements of two-way travel-time differences between the nodes deployed on the perimeter of the surveying area to invert/map the ocean current inside the area. Data at different times can be related using a Kalman filter, and given an ocean circulation model, one can in principle now cast and even forecast current distribution given an initial distribution and/or the travel-time difference data on the boundary. However, an ocean circulation model requires many inputs (many of them often not available) and is unpractical for estimation of the current field. A simplified form of the discretized Navier-Stokes equation is used to show that the future velocity state is just a weighted spatial average of the current state. These weights could be obtained from an ocean circulation model, but here in a data driven approach, auto-regressive methods are used to obtain the time and space dependent weights from the data. It is shown, based on simulated data, that the current field tracked using a Kalman filter (with an arbitrary initial condition) is more accurate than that estimated by the standard methods where data at different times are treated independently. Real data are also examined.

Biodegradable hybrid-structured nanofibrous membrane supported chemoprotective gene therapy enhances chemotherapy tolerance and efficacy in malignant glioma rats

Chemotherapy is ineffective for treating malignant glioma (MG) because of the low therapeutic levels of pharmaceuticals in tumour tissues and the well-known tumour resistance. The resistance to alkylators is modulated by the DNA repair protein O⁶-alkylguanine-DNA alkyltransferase (AGT). O⁶-benzylguanine (O⁶-BG) can irreversibly inactivate AGT by competing with O⁶-methylguanine and has been confirmed to increase the therapeutic activity of alkylators. We developed hybrid-structured poly[(d,l)-lactide-co-glycolide] nanofibrous membranes (HSNMs) that enable the sequential and sustained release of O⁶-BG and two alkylators (carmustine and temozolomide [TMZ]). HSNMs were surgically instilled into the cerebral cavity of pathogen-free rats and F98 glioma-bearing rats. The release behaviours of loaded drugs were quantified by using high-performance liquid chromatography. The treatment results were compared with the rats treated with intraperitoneal injection of O⁶-BG combined with surgical implantation of carmustine wafer and oral TMZ. The HSNMs revealed a sequential drug release behaviour with the elution of high drug concentrations of O⁶-BG in the early phase, followed by high levels of two alkylators. All drug concentrations remained high for over 14 weeks. Tumour growth was slower and the mean survival time was significantly prolonged in the HSNM-treated group. Biodegradable HSNMs can enhance therapeutic efficacy and prevent toxic systemic effects.

Estimating the delay-Doppler of target echo in a high clutter underwater environment using wideband linear chirp signals: Evaluation of performance with experimental data

A chirp signal is a signal with linearly varying instantaneous frequency over the signal bandwidth, also known as a linear frequency modulated (LFM) signal. It is widely used in communication, radar, active sonar, and other applications due to its Doppler tolerance property in signal detection using the matched filter (MF) processing. Modern sonar uses high-gain, wideband signals to improve the signal to reverberation ratio. High gain implies a high product of the signal bandwidth and duration. However, wideband and/or long duration LFM signals are no longer Doppler tolerant. The shortcoming of the standard MF processing is loss of performance, and bias in range estimation. This paper uses the wideband ambiguity function and the fractional Fourier transform method to estimate the target velocity and restore the performance. Target velocity or Doppler provides a clue for differentiating the target from the background reverberation and clutter. The methods are applied to simulated and experimental data.

Targeted concurrent and sequential delivery of chemotherapeutic and antiangiogenic agents to the brain by using drug-loaded nanofibrous membranes

Glioblastoma is the most frequent and devastating primary brain tumor. Surgery followed by radiotherapy with concomitant and adjuvant chemotherapy is the standard of care for patients with glioblastoma. Chemotherapy is ineffective, because of the low therapeutic levels of pharmaceuticals in tumor tissues and the well-known tumor-cell resistance to chemotherapy. Therefore, we developed bilayered poly(d,l)-lactide-co-glycolide nanofibrous membranes that enabled the sequential and sustained release of chemotherapeutic and antiangiogenic agents by employing an electrospinning technique. The release characteristics of embedded drugs were determined by employing an in vitro elution technique and high-performance liquid chromatography. The experimental results showed that the fabricated nanofibers showed a sequential drug-eluting behavior, with the release of high drug levels of chemotherapeutic carmustine, irinotecan, and cisplatin from day 3, followed by the release of high concentrations of the antiangiogenic combretastatin from day 21. Biodegradable multidrug-eluting nanofibrous membranes were then dispersed into the cerebral cavity of rats by craniectomy, and the in vivo release characteristics of the pharmaceuticals from the membranes were investigated. The results suggested that the nanofibrous membranes released high concentrations of pharmaceuticals for more than 8 weeks in the cerebral parenchyma of rats. The result of histological analysis demonstrated developmental atrophy of brains with no inflammation. Biodegradable nanofibrous membranes can be manufactured for long-term sequential transport of different chemotherapeutic and anti-angiogenic agents in the brain, which can potentially improve the treatment of glioblastoma multiforme and prevent toxic effects due to systemic administration.

Data-based depth estimation of an incoming autonomous underwater vehicle

The data-based method for estimating the depth of a moving source is demonstrated experimentally for an incoming autonomous underwater vehicle traveling toward a vertical line array (VLA) of receivers at constant speed/depth. The method assumes no information on the sound-speed and bottom profile. Performing a wavenumber analysis of a narrowband signal for each hydrophone, the energy of the (modal) spectral peaks as a function of the receiver depth is used to estimate the depth of the source, traveling within the depth span of the VLA. This paper reviews the theory, discusses practical implementation issues, and presents the data analysis results.

Vitamin E homologues α- and γ-tocopherol are not associated with bone turnover markers or bone mineral density in peri-menopausal and post-menopausal women

In a large cohort of older women, we investigated the relationships that different forms of vitamin E may have with bone turnover markers and bone mineral density (BMD). We found a suggestive positive association between serum alpha-tocopherol and BMD at the femoral neck, but no other clinically relevant observations.

INTRODUCTION

Vitamin E has anti-oxidant and anti-inflammatory properties hypothesized to benefit bone, but limited studies exist regarding its homologues. We examined circulating and dietary α- and γ-tocopherols with bone turnover markers (BTMs) and bone mineral density (BMD), and the role of inflammation in this relationship.

METHODS

We performed two cross-sectional analyses from two visits (V2, 1997-1999, n = 3883; V3, 2007-2011, n = 2130) of the Aberdeen Prospective Osteoporosis Screening Study. Dietary and supplement intakes by food frequency questionnaire were assessed at both visits. V2 BTMs (urinary free pyridinoline and deoxypyridinoline, serum N-terminal propeptide of type 1 collagen) and V3 serum α- and γ-tocopherols, inflammatory markers (interleukin-6 [IL-6], serum amyloid A [SAA], high-sensitivity C-reactive protein [hs-CRP], E-selectin) and dual X-ray absorptiometry BMD at the femoral neck and lumbar spine were collected. Food sources of tocopherol homologues and diet-serum correlations were determined. The relationships between dietary tocopherols and BTMs (V2), and dietary and serum tocopherols with BMD (V3) were examined by multivariable regression (adjusting for age, cholesterol, inflammatory markers, carotenoids, body mass index, physical activity level, alcohol intake, smoking status and national deprivation category).

RESULTS

Serum γ-tocopherol was associated with increasing concentrations of hs-CRP, SAA and E-selectin (P-trend all <0.0001), while α-tocopherol was associated with decreasing concentrations of IL-6 and hs-CRP (P-trend all <0.001). Controlling for covariates, serum α-tocopherol was positively associated with BMD at the femoral neck (β = 0.002, P = 0.04) among those not reporting vitamin E supplementation.

CONCLUSION

We did not find biologically meaningful results between dietary and tocopherol homologues with BTMs or BMD.

Phase-contrast magnetic resonance imaging for the evaluation of wall shear stress in the common carotid artery of a spontaneously hypertensive rat model at 7T: Location-specific change, regional distribution along the vascular circumference, and reproducibility analysis

PURPOSE

To measure wall shear stress (WSS) in the common carotid arteries (CCA) of a spontaneously hypertensive rat (SHR) model and a normotensive Wistar Kyoto rat (WKY) model by 2D phase-contrast magnetic resonance imaging (PC-MRI).

MATERIALS AND METHODS

PC-MRI was performed on 7 SHR and 7 WKY at ages of 4 and 7months at a 7T scanner. Images in the middle CCA (CCAmid) and in the bifurcation of CCA (CCAbifur) were acquired. The WSS values for differentiating characteristics between two models were calculated. Further, its location-specific change, regional distribution along the CCA circumference, and the reproducibility were evaluated.

RESULTS

In the 4-month-old rats, SHR showed lower temporal averaged WSS (WSSavg) and peak systolic WSS (WSSs) in the CCAbifur in comparison with WKY (WSSavg: 0.95±0.18 vs. 1.30±0.36N/m(2) (P<0.01); WSSs: 1.68±0.70 vs. 3.22±2.49N/m(2) (P<0.05)). We observed the same trends in the 7-month-old rats. In the SHR model, the WSSavg was lower in the CCAbifur than in the CCAmid. The regional distribution of WSSavg along the circumference of CCA showed lower values in WKY, particularly in posterior segments of CCAbifur. The intra-observer, intra-scan and inter-scan reproducibility was acceptable and the disagreements were ranged from -0.05 to 0.06N/m(2).

CONCLUSION

This study evaluated WSS in SHR and WKY models by 2D PC-MRI. High reproducibility analyses further indicated the reliability of measurements of WSS in the CCA of SHR and WKY models using PC-MRI at 7T.