Objective To investigate the effect of gravity and lung volume on MR perfusion imaging of human lung using an arterial spin labeling sequence called flow sensitive alternating inversion recovery(FAIR).Methods Magnetic resonance imaging of lung perfusion was performed in supine position in ten healthy volunteers on a 1.5 T whole body scanner(GE medical system).Five sequentially coronal slices with the gap of 3cm from dorsal to ventral(labeled as P3,P6,P9,P12,P15,respeectivly)were obtained on end respiration and the relative pulmonary blood flow(rPBF)was measured.Another coronal perfusion-weighted image of P3 slice was obtained on end inspiration.Tagging efficiency of pulmonary parenchyma with IR(⊿SI%),the rPBF and area of the P3 slice were analyzed.respectively.Paired Student's t test was used for statistical analysis.Results (1)In the direction of gravity,an increase in rPBF of the gravity-dependent lung was found.rPBF of right lung from dorsal to ventral were 100.57±18.22,79.57±12.36,61.65±11.15,48.92±9.96,41.20±9.88,respectively；and that of left lung were 106.61±26.99,78.89±11.98,64.00±13.64,51.27±8.95,43.04±12.18.No statistical differences between P12 and P15,there were significant statistic differences of any other two coronal planes.But along an isogravitational plane,no statistical difference was observed.Regression coefficients of right and left lung were -4.98 and -5.16,respectively.This means the rPBF of right lung falls by 4.98 for each centimeter above the dorsal and that of left lung falls by 5.16.(2)For(⊿)SI%,rPBF and area,there were significant statistic differences at different respiratory phases(P＜0.05).(⊿)SI%,rPBF,area at expiration phase vs.inspiration phase were 1.12±0.31 vs 0.71±0.18,90.78±17.35 vs 52.85±8.75,(12.59±3.23)×103mm2 vs (17.77±4.24)×103mm2 for right lung;and 1.01±0.24 vs 0.70±0.11,91.08±18.68 vs 54.58±10.70,(12.34±3.08)×103mm2 vs(17.34±4.98)×103mm2 for left lung.Greater (⊿)SI%and increased perfusion were observed on end expiration than on end inspiration.The area was larger on end inspiration than on end expiration.Conclusions The FAIR is sensitive to perfusion changes in the gravity-dependent lung.Pulmonary blood flow is less in a state of high lung inflation than in a low state(inspiration vs.expiration).Positioning the patient so that the area of interest is down-gravity and breath-hold on end expiration may improve visibility of perfusion defects.
Key words:
Pulmonary circulation; Vascular capacitance; Magnetic resonance imaging; Perfusion
Aortic valve replacement (AVR) is generally accepted as the standard operation to treat symptomatic aortic valvular diseases now.AVR can apparently improve the clinical symptoms and hemodynamics of patients with aortic valve stenosis or regurgitation.AVR has good effect and a higher long-term survival rate. Although transcatheter aortic valve implantation (TAVI) has also been accepted as an effective means to treat aortic valvular diseases, AVR is still the most reliable surgical procedure.Echocardiography is the most important method to diagnose aortic valve stenosis or regurgitation.Echocardiography is also a safe and reliable non-invasive detecting technique, which has important value on having preoperative evaluation, determining operation indication, choosing operation procedure and judging prognosis.The early complications of AVR affect the prognosis of patients after the surgery.Echocardiography is the most widely used clinical methodology for detecting the early complications that occurred within 30 days after the surgical procedure of AVR.Conventional echocardiography is most widely used, but new echocardiographic techniques such as tissue Doppler imaging(TDI), two-dimensional or three-dimensional speckle tracking imaging (2D or 3D-STI) and stress echocardiography are getting more and more attentive in recent years.However, there isn′t enough sufficient evidence to prove the predictive value of echocardiography on early complications after AVR.This article reviewed echocardiographic detective methods of main early complications after AVR, which may provide evidence to study the predictive value of preoperative echocardiographic index on early postoperative complications.
Key words:
Aortic valve replacement; Echocardiography; Early complications
ABSTRACT The geological structure of coal mines and the precise prediction of coal seam gas content are key factors in creating the transparent working face, and they also represent an important aspect of intelligent coal mining. The traditional technology of coal seam geological construction and gas content prediction is not advanced. This paper presents a methodology for 3D implicit geological modeling and visualization using Gempy and PyVista libraries, as well as gas prediction and distribution based on the Scikit‐learn library, all of which are underpinned by machine learning techniques. Under this method, the geological modeling of coal seam was converted to the kriging interpolation algorithm based on machine learning of coal seam thickness data. The problem of coal seam gas content is converted into a regression prediction problem of coal seam characteristic values and gas content target values based on machine learning. The pykrige package under Python is used to interpolate the obtained coal seam thickness. Based on the linear regression prediction model, loss function and other prediction methods and algorithms, the accurate prediction of coal seam gas content based on borehole data is realized. Under the above various operations, a 3D geological model of the mine and the gas content distribution map of the coal seam are finally obtained. Compared to actual borehole data and gas geological maps, this method offers high precision and enhanced efficiency.
Introduction: To evaluate the different multi-detector computed tomography (MDCT) features between pulmonary malignant focal ground-glass opacity (fGGO) nodules and solid nodules of 3 cm or less in diameter. Methods: One hundred and five malignant solid nodules and 48 malignant fGGOs confirmed by pathology were retrospectively analysed with regard to the patient's demographic data, nodule size and MDCT features (shape, margin, interface, internal characteristics and adjacent structure). Differences were analysed using the Fisher exact test or Mann–Whitney U-test. Results: The male to female ratio of patients with malignant solid nodules (60:45) was higher than that with malignant fGGOs (18:30) (P < 0.05). There was no significant difference in either patient's age (P > 0.05) or nodule size (P > 0.05). The frequency of irregular shape (4% vs. 21%), spiculation (57% vs. 40%), vacuole sign (11% vs. 52%) and natural air bronchograms (0% vs. 24%) was significantly different between malignant solid nodules and fGGOs. No differences were found in the frequency of lobulation, cusp angle, spine-like process, interface and adjacent structure between the two groups (P > 0.05). Conclusion: Malignant fGGOs and solid nodules showed mostly similar MDCT features. For malignant fGGOs, the frequency of irregular shape, vacuole sign and natural air bronchograms was higher than that in solid nodules, but the frequency of spiculation was lower than that in solid nodules.
Abstract Background: To investigate left atrial(LA) function in essential hypertension(EHT) patients by using volume-derived values, two-dimensional strain. Methods: 51 normal subjects and 95 EHT patients(without LVH: 50, and with LVH: 45) were enrolled for this research. LA Volume-derived index was measured in apical 4-, 2-chamber views by Simpson′s method. LA strain(S-reservoir, S-conduit, S-booster pump) and strain rate (SR-reservoir, SR-conduit, SR-booster pump), representing the reservoir, conduit and booster pump functions, respectively, were measured by two-dimensional speckle tracking echocardiography(STE). Results: Volume-derived values(contain Total LAEF, passive LAEF and active LAEF) and strain-derived values(S-reservoir, S-conduit, Sr-reservoir, Sr-conduit and Sr-booster pump) in EHT patients were significantly lower than normal subjects. Correlation test showed LA stiffness had a strong correlation with LA conduit function in EHT patients. The AUC values were higher for detection LA conduit function than LA reservoir and booster pump function in EHT patients. LA expansion index and LA stiffness also have the higher AUC with higher sensitivity and specificity values for detection the LA dysfunctions in EHT patients. Conclusions: In this study, we concluded that LA functions were damaged in EHT patients, which could be detect by LA volume-derived values and two-dimensional strain sensitively and reproductively. LA stiffness maybe a predictor for LV remodelling in EHT patients.
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