Segmentation of the geometric morphology of abdominal aortic aneurysm is important for interventional planning. However, the segmentation of both the lumen and the outer wall of aneurysm in magnetic resonance (MR) image remains challenging. This study proposes a registration based segmentation methodology for efficiently segmenting MR images of abdominal aortic aneurysms. The proposed methodology first registers the contrast enhanced MR angiography (CE-MRA) and black-blood MR images, and then uses the Hough transform and geometric active contours to extract the vessel lumen by delineating the inner vessel wall directly from the CE-MRA. The proposed registration based geometric active contour is applied to black-blood MR images to generate the outer wall contour. The inner and outer vessel wall are then fused presenting the complete vessel lumen and wall segmentation. The results obtained from 19 cases showed that the proposed registration based geometric active contour model was efficient and comparable to manual segmentation and provided a high segmentation accuracy with an average Dice value reaching 89.79%.

Object To evaluate an accelerated 4D flow MRI method that provides a high temporal resolution in a clinically feasible acquisition time for intracranial velocity imaging. Materials and Methods Accelerated 4D flow MRI was developed by using a pseudo-random variable-density Cartesian undersampling strategy (CIRCUS) with the combination of k-t, parallel imaging and compressed sensing image reconstruction techniques (k-t SPARSE-SENSE). 4D flow data were acquired on five healthy volunteers and eight patients with intracranial aneurysms using CIRCUS (acceleration factor of R=4, termed CIRCUS4) and GRAPPA (R=2, termed GRAPPA2) as the reference method. Images with three times higher temporal resolution (R=12, CIRCUS12) were also reconstructed from the same acquisition as CIRCUS4. Qualitative and quantitative image assessment was performed on the images acquired with different methods, and complex flow patterns in the aneurysms were identified and compared. Results 4D flow MRI with CIRCUS was achieved in 5 minutes and allowed further improved temporal resolution of <30 ms. Volunteer studies showed similar qualitative and quantitative evaluation obtained with the proposed approach compared to the reference (overall image scores: GRAPPA2 3.2±0.6, CIRCUS4 3.1±0.7, and CIRCUS12 3.3±0.4; difference of the peak-velocities: −3.83±7.72 cm/s between CIRCUS4 and GRAPPA2, −1.72±8.41 cm/s between CIRCUS12 and GRAPPA2). In patients with intracranial aneurysms, the higher temporal resolution improved capturing of the flow features in intracranial aneurysms (pathline visualization scores: GRAPPA2 2.2±0.2, CIRCUS4 2.5±0.5, and CIRCUS12 2.7±0.6). Conclusion The proposed rapid 4D flow MRI with a high temporal resolution is a promising tool for evaluating intracranial aneurysms in a clinically feasible acquisition time.

Object This work presents a highly-accelerated, self-gated, free-breathing 3D cardiac cine MRI method for cardiac function assessment. Materials and Methods A golden-ratio profile based variable-density, pseudo-random, Cartesian undersampling scheme was implemented for continuous 3D data acquisition. Respiratory self-gating was achieved by deriving motion signal from the acquired MRI data. A multi-coil compressed sensing technique was employed to reconstruct 4D images (3D+time). 3D cardiac cine imaging with self-gating was compared to bellows gating and the clinical standard breath-held 2D cine imaging for evaluation of self-gating accuracy, image quality, and cardiac function in eight volunteers. Reproducibility of 3D imaging was assessed. Results Self-gated 3D imaging provided an image quality score of 3.4 ± 0.7 v.s. 4.0±0 with the 2D method (p=0.06). It determined left ventricular end-systolic volume as 42.4±11.5mL, end-diastolic volume as 111.1±24.7 mL, and ejection fraction as 62.0±3.1%, which were comparable to the 2D method, with bias±1.96×std of −0.8±7.5 mL (p=0.90), 2.6±3.3mL (p=0.84) and 1.4±6.4% (p=0.45) respectively. Conclusion The proposed 3D cardiac cine imaging method enables reliable respiratory self-gating performance with good reproducibility, and provides comparable image quality and functional measurements to 2D imaging, suggesting that self-gated, free-breathing 3D cardiac cine MRI framework is promising for improved patient comfort and cardiac MRI scan efficiency.

Spatial distribution of soil salinity can be estimated based on its environmental factors because soil salinity is strongly affected and indicated by environmental factors. Different with other properties such as soil texture, soil salinity varies with short-term time. Thus, how to choose powerful environmental predictors is especially important for soil salinity. This paper presents a similarity-based prediction approach to map soil salinity and detects powerful environmental predictors for the Huanghe (Yellow) River Delta area in China. The similarity-based approach predicts the soil salinities of unsampled locations based on the environmental similarity between unsampled and sampled locations. A dataset of 92 points with salt data at depth of 30-40 cm was divided into two subsets for prediction and validation. Topographical parameters, soil textures, distances to irrigation channels and to the coastline, land surface temperature from Moderate Resolution Imaging Spectroradiometer (MODIS), Normalized Difference Vegetation Indices (NDVIs) and land surface reflectance data from Landsat Thematic Mapper (TM) imagery were generated. The similarity-based prediction approach was applied on several combinations of different environmental factors. Based on three evaluation indices including the correlation coefficient (CC) between observed and predicted values, the mean absolute error and the root mean squared error we found that elevation, distance to irrigation channels, soil texture, night land surface temperature, NDVI, and land surface reflectance Band 5 are the optimal combination for mapping soil salinity at the 30-40 cm depth in the study area (with a CC value of 0.69 and a root mean squared error value of 0.38). Our results indicated that the similarity-based prediction approach could be a vital alternative to other methods for mapping soil salinity, especially for area with limited observation data and could be used to monitor soil salinity distributions in the future.

Purpose: To achieve single breathhold whole heart cardiac CINE imaging with improved spatial resolution and temporal resolution by using a multi-echo three-dimensional (3D) hybrid radial SSFP acquisition. Materials and Methods:Multi-echo 3D hybrid radial SSFP acquisitions were used to acquire cardiac CINE imaging within a single breathhold. An optimized interleaving scheme was developed for view ordering throughout the cardiac cycle.Results: Whole heart short axis views were acquired with a spatial resolution of 1.3 Â 1.3 Â 8.0 mm 3 and temporal resolution of 45 ms, within a single 17 s breathhold. The technique was validated on eight healthy volunteers by measuring the left ventricular volume throughout the cardiac cycle and comparing with the conventional 2D multiple breathhold technique. The left ventricle functional measurement bias of our proposed 3D technique from the conventional 2D technique: end diastolic volume À3.3 mL 6 13.7 mL, end systolic volume 1.4 mL 6 6.1 mL, and ejection fraction À1.7% 6 4.3%, with high correlations 0.94, 0.97, and 0.91, accordingly. Conclusion:A multi-echo 3D hybrid radial SSFP acquisition was developed to allow for a whole heart cardiac CINE exam in a single breathhold. Cardiac function measurements in volunteers compared favorably with the standard multiple breathhold exams.

BL showed significant effectiveness for the treatment of neonatal PA under ultrasound monitoring. This treatment is easy to operate, and no adverse side effects were observed. Thus, BL should be considered for clinical application.

Lung ultrasound has been extensively used to diagnose many types of lung disease. This study aimed to evaluate the pulmonary reasons for long-term oxygen dependence (LTOD) in premature infants using lung ultrasound.Lung ultrasound was routinely performed in 50 premature infants clinically diagnosed with bronchopulmonary dysplasia (BPD).Among the 50 patients studied, there were 9 cases of atelectasis, 4 cases of pneumonia, 2 cases of severe pulmonary edema, and 3 cases of pulmonary edema and consolidation that coexisted with BPD. The oxygen dependence of the babies either completely resolved or significantly decreased following appropriate treatments.More than one-third of the cases of LTOD in premature babies were caused by either BPD alone or diseases other than BPD. Lung ultrasound plays an important role in differentiating pulmonary causes of LTOD in patients with BPD, and the results of our study suggest that modifying the diagnostic criteria for BPD may be necessary.

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