Reduced Field of View APT Imaging of Rectum (RAPTOR) at 3T MRI Scanner / 生物化学与生物物理进展

ObjectiveThe chemical exchange saturation transfer (CEST) technique has become a valuable tool in diagnosing metabolic changes associated with cerebral and systemic diseases, leveraging the calculation of compounds with exchangeable protons in proximity to water molecules. Specifically, the amide proton transfer (APT) CEST technique has shown promise in diagnosing cerebral strokes and tumors by comparing altered endogenous proteins or peptides with normal tissues. Reduced field of view (rFOV) imaging technology has been widely used in the diagnosis of small organ lesions in the body. In this study, we aim to apply the rFOV imaging to identify CEST signals in the rectum, investigating the potential utility of rFOV technique in clinical diagnosis of rectal diseases and providing metabolic insights for chemoradiotherapy. MethodsMRI images of eleven healthy volunteers were acquired using transverse Full_FOV and rFOV CEST imaging on a 3T scanner. The resolution was set at 2.5×2.5×6 mm³ and 1.5×1.5×6 mm³ for Full_FOV or the rFOV method. Saturation powers of 0.7 μT and 2 μT were applied. For the 2 μT saturation, MTRasym at ±3.5 ppm was employed, while for 0.7 μT saturation, Lorentzian difference was used for CEST quantification of the contrast maps and curves. ResultsThe rFOV method has the advantage of halving the scan time while maintaining the same contrast as the Full_FOV method. When compared to Full_FOV methods, rFOV methods exhibited nearly identical Z_spec and very similar MTRasym curves. Additionally, rFOV with a 1.5 mm×1.5 mm in-plane resolution could be achieved in approximately 3 min. rFOV method displayed better structural details for the entire rectum, including CEST contrast maps and quantitative curves. ConclusionCEST MRI proves valuable in diagnosing rectal diseases, and employing the rFOV technique could provide higher spatial and temporal resolution. CEST MRI should be the preferred choice for offering improved diagnostic capabilities with its potential for rectal disease diagnosis.

A long-term ischemic stroke risk score model in patients aged 60 years and older with obstructive sleep apnea: a multicenter prospective cohort study / 南方医科大学学报

OBJECTIVE@#To analyze the independent risk factors of long-term ischemic stroke and establish a nomogram for predicting the long-term risks in elderly patients with obstructive sleep apnea (OSA).@*METHODS@#This multicenter prospective cohort study was conducted from January, 2015 to October, 2017 among consecutive elderly patients (≥60 years) with newly diagnosed OSA without a history of cardio-cerebrovascular diseases and loss of important clinical indicators. The follow-up outcome was the occurrence of ischemic stroke. The baseline demographic and clinical data, sleep parameters, laboratory and ultrasound results were collected from all the patients, who were randomized into the modeling group (n=856) and validation group (n=258) at a 3∶1 ratio. LASSO regression was used for variable reduction and dimension screening, and the risk score prediction model of ischemic stroke was established based on Cox proportional hazard regression.@*RESULTS@#In the total of 1141 patients enrolled in this study, 58 (5.08%) patients experienced ischemic stroke during the median follow-up of 42 months (range 41-54 months). The cumulative incidence of ischemic stroke was 5.14% in the model group and 4.91% in the verification group (P < 0.05). Age (HR=3.44, 95% CI: 2.38- 7.77), fasting blood glucose (FPG) (HR=2.13, 95% CI: 1.22-3.72), internal diameter of the ascending aorta (HR=2.60, 95% CI: 1.0- 4.47), left atrial anteroposterior diameter (HR=1.98, 95% CI: 1.75-2.25) and minimum oxygen saturation (LSpO2) (HR=1.57, 95% CI: 1.20-1.93) were identified as independent risk factors for ischemic stroke (P < 0.05 or 0.01). A long-term ischemic stroke risk score model was constructed based the regression coefficient ratios of these 5 risk variables. Before and after the application of the Bootstrap method, the AUC of the cohort risk score model was 0.84 (95% CI: 0.78- 0.90) and 0.85 (95% CI: 0.78- 0.89) in the model group and was 0.83 (95% CI: 0.73-0.93) and 0.82 (95%CI: 0.72-0.90) in the verification group, respectively, suggesting a good prediction efficiency and high robustness of the model. At the best clinical cutoff point, the cumulative incidence of ischemic stroke was significantly higher in the high-risk group than in the low-risk group (P=0.021).@*CONCLUSION@#This model can help to identify high-risk OSA patients for early interventions of the risks of ischemic stroke associated with OSA.

Design and Verification of Human Metabolic Measurement System Based on STM32 / 中国医疗器械杂志

A high-precision human metabolic measurement system is designed. The system uses STM32F103 as the main control chip to acquire oxygen, carbon dioxide and flow signals to calculate four quantitative indicators: oxygen consumption(VO2), carbon dioxide production(VCO2), respiratory entropy(RQ) and resting energy metabolism(REE), and finally uses an upper computer to display the calculation results.In this paper, the signal acquisition circuit design was carried out for the oxygen sensor, carbon dioxide sensor and flow sensor, and the validity of the device was verified with the American machine MGCDiagnositcs using Bland-Altman analysis method, and the results showed that the four parameters of VO2,VCO2, RQ and REE of both devices fell in the agreement interval of more than 95%. The device thus provides accurate metabolic measurements and offers an effective tool for the field of general health and clinical nutrition support in China.

Transcranial Doppler-assisted intra-arterial thrombolysis for patients with acute ischemic stroke / 中华神经医学杂志

Objective To investigate the clinical efficacy of transcranial Doppler(TCD)-assisted interventional intra-arterial thrombosis in patients with acute ischemic stroke.Methods This clinical trial enrolled 22 patients with acute ischemic stroke(13 with occlusion of the middle cerebral artery within 6 h of symptom onset; 9 with occlusion of the base artery within 12 h of symptom onset); occlusive arterial cannula was performed and recombinant tissue plasminogen activator(rt-PA,20 mg)was injected to perform interventional intra-arterial thrombosis; and TCD ultrasonography of low frequency(2 MHz)and low intensity(0.25 W/cm2)was performed to assist the thrombosis.Cranial CT was performed again right after the operation and 24 h after the operation to observe the recanalization rate and intracranial hemorrhage; NIHSS scores and Barthel index scores were compared before and after the operation.Results The percentage ofrecanalization was 77.27％(17/22),including 22.73％(5/22)complete recanalization and 54.55％(12/22)partial recanalization; non-symptomatic intracerebral hemorrhage occurred in 3 patients and no symptomatic intracerebral hemorrhage was noted.NIHSS and Barthel index scores after the operation were obviously higher than those before the operation,indicating that favorable outcomes were achieved after thrombosis.Conclusion TCD-assited interventional intra-arterial thrombosis with rt-PA,significantly improving the recanalization rate of occlusive artery and remarkably reducing the happening ofintracerebral hemorrhage,can improve the prognosis and enjoy good clinical efficacy and safety in treatment of acute ischemic stroke.