Application of hyperbolic heat transfer model in atrial fibrillation microwave ablation / 生物医学工程学杂志

The effect of relaxation time in hyperbolic heat transfer model on the temperature field of microwave ablation of atrial fibrillation was investigated. And the results were compared with those calculated by Pennes model. A three-dimensional model of microwave ablation of atrial fibrillation was constructed. The relaxation time (

The application of magnetic resonance imaging-guided microwave ablation for lung cancer

Context: It is necessary to explore a minimally invasive, effective, and efficient treatment for those lung cancer patients who are poor candidates for surgery. Aim: This study aimed to investigate the application of microwave ablation (MWA) in the treatment of lung cancer. Settings and Design: A total of 43 patients with 44 pulmonary lesions were examined following identical procedures before being randomly divided into two groups. The experimental group consists of 17 patients with a total of 18 pulmonary lesions, while the control group consists of 26 patients with a total of 26 pulmonary lesions. Materials and Methods: The experimental group was treated using magnetic resonance imaging (MRI)-guided MWA while the control group was treated using computer tomography (CT)-guided MWA. A transverse relaxation time-turbo spin echo (T2-TSE) sequence was used for signal collection in the experimental group to determine puncture location and microwave needle position while T2-TSE, T1-turbo field echo, and diffusion-weighted MRI (DWI) sequences were used for timely efficacy evaluation. Whereas in the control group, CT axial scanning was performed to serve similar purposes. Statistical Analysis Used: A nonparametric Wilcoxon test, median (M [25%, 75%]). Results: All of the 44 lesions were successfully located on the first attempt. The mean time for scanning and locating lung lesions under MRI and CT guidance were 64.53 and 42.96 min, the mean times of positioning were 12 and 18 min, and the mean durations of MWA were 12.48 and 15.06 min, respectively. Conclusions: As a minimally invasive method for treating lung tumors, MRI-guided MWA requires fewer localization scans, a shorter MWA duration, no radiation, real-time observation of the curative effect, and it prevents overtreatment

Effects of association state on decocting rate of mangiferin in Pingfei Decoction by using low-field and high-field NMR / 中草药

Objective: To study the effects of association complexes on extraction and separation behavior of mangiferin in Pingfei Decoction by low-field and high-field NMR. Methods Using the T2 relaxation time and chemical shifts value of hydrogen as index, and group DNJ-citric acid as control, the relaxation characteristrics of hydrogen in association state was analyzed by low field NMR to verify the structure of association complexes combined with high-field NMR. Results DNJ and mangiferin existed in the form of association state with larger molecular weight, which inhibited the migration of components from medicinal materials to solution and caused lower transmittance. And the T2 peak shifted to the left in the spectrum, and the chemical shift in the high field nuclear magnetic field also changed. Conclusion This experiment clarified the mechanism of the effect of presence of components on extraction and separation behavior of mangiferin and provided technical support for studying the decocting method and mechanism of Chinese herbal compound.

Comparison Thigh Skeletal Muscles between Snowboarding Halfpipe Athletes and Healthy Volunteers Using Quantitative Multi-Parameter Magnetic Resonance Imaging at Rest / 中华医学杂志(英文版)

<p><b>Background</b>Magnetic resonance (MR) imaging provides a unique, noninvasive diagnostic platform to quantify the physiological and biochemical variables of skeletal muscle at rest. This study was to investigate the difference in thigh skeletal muscles between snowboarding halfpipe athletes and healthy volunteers via multiparametric MR imaging.</p><p><b>Methods</b>A comparative study was conducted between 12 healthy volunteers and 14 snowboarding halfpipe athletes. MR scanning targeted the left leg at the level of the proximal thigh on a 3.0T MR system. The measured parameters compared between the two groups included T1, T2, T2* relaxation times, fat fraction (FF), and cross-sectional area (CSA) of the quadriceps femoris and the hamstring muscles. Statistical analysis was carried out using independent sample t-test. Interrater reliability was also assessed with intraclass correlation coefficients (ICCs).</p><p><b>Results</b>It was statistically equivalent between two groups in age, body mass index, thigh circumference, calf circumference, systolic blood pressure, and resting heart rate (all P > 0.05). However, the T1 and T2 values of the hamstring muscles in the athlete group were found to be significantly shorter than those in control group (T1: 1063.3 ± 24.1 ms vs. 1112.0 ± 38.2 ms in biceps femoris, 1050.4 ± 31.2 ms vs. 1095.0 ± 39.5 ms in semitendinosus, 1053.1 ± 31.7 ms vs. 1118.4 ± 40.0 ms in semimembranosus, respectively; T2: 33.4 ± 0.7 ms vs. 36.1 ± 1.9 ms in biceps femoris, 34.6 ± 2.0 ms vs. 37.0 ± 1.9 ms in semitendinosus, 36.9 ± 1.5 ms vs. 38.9 ± 2.4 ms in semimembranosus, respectively; all P < 0.05) although T2* relaxation time was detected with no significant difference. The FF of the hamstring muscles was obviously less than the control group (5.5 ± 1.9% vs. 10.7 ± 4.7%, P < 0.001). In addition, the quadriceps' CSA in the athlete group was substantially larger than the control group (8039.0 ± 1072.3 vs. 6258.2 ± 852.0 mm, P < 0.001). Interrater reliability was excellent (ICC: 0.758-0.994).</p><p><b>Conclusion</b>Multiple MR imaging parameters indicated significant differences between snowboarding halfpipe athletes and healthy volunteers in the thigh skeletal muscles.</p>

Analysis on moisture transfer laws of Chaenomeles sinensis during drying process based on low-field NMR / 中草药

Objective To study the moisture transfer laws of Chaenomeles sinensis in different drying processes. Methods Using the non-destructive and non-invasive technique of low field-nuclear magnetic resonance (LF-NMR), the transverse relaxation time (T2) inversion spectrum of C. sinensis slice was monitored under different drying methods (hot air drying, drying after evaporation, segmental drying and drying in the shade) to analyze the changes of moisture migration. Results There were three different types water that were detected in C. sinensis (free water > bound water > immobilized water). The internal water distribution and water content changed during drying process. The moisture changes were similar in hot air drying, drying after steaming, and drying in shade, the total water gradually decreased, and the combining degree between moisture and non-water components enhanced. Steaming promoted the water loss rate of C. sinensis slice, the water loss rate was higher in drying after steaming than in hot air drying, and the difference was significant (P < 0.05). During the intermittent drying, the conversion of different states of water would occur in order to return to a relatively stable equilibrium. During the low temperature drying process, immobilized water content decreased and free water content increased. The low-temperature drying has less damage to the tissue, which is more conducive to the conversion of immobilized water into free water, and thus the water dissipated faster. During the early of drying, high temperature caused tissue structure damage, the bonding force between water and non-aqueous tissue would be strengthened because of the tissue shrinkage. Conclusion The three different types water content and peak area in T2 was positively correlated. The LF-NMR technique would provide useful guides for the investigation of water distribution and variation of C. sinensis, which will provide a theoretical basis for C. sinensis processing.

Effect of rocuronium on muscle relaxants time in patients with different types of cancer / 中国基层医药

Objective To observe the effect of rocuronium on muscle relaxation time in patients with different types of cancer.Methods Sixty-four patients with tumor were enrolled.The patients underwent tumor resection under general anesthesia.They were divided into malignant tumor group (control group) and benign tumor group (observation group) according to different tumor type,32 cases in each group.Remifentanil,propofol,rocuronium were intravenously injected to induce anesthesia.The first convulsive response (T1) in the four strangulated stimuli up to the maximum inhibition of tracheal intubation and recorded time.Intravenous infusion of propofol,plasma concentration of 3-5μg/mL and intermittent intravenously injected remifentanil maintenance anesthesia.50 mg of rocuronium bromide diluted in 0.9％ NaC1 50ml,when T1 returned to 10％,the patients were given intravenous infusion of dilute rocuronium,to maintain patients with T1 in 5％ to 10％,until the patients'consciousness recovery,removal of tracheal tube.Results There were no statistically significant differences in SBP,DBP,MAP and HR between the two groups (t =0.15,P =0.44;t =0.17,P =0.43;t =0.09,P =0.46;t =0.31,P =0.38;).The DBP,MAP,HR levels increased during intubation,SBP decreased,and the differences of SBP and DBP were statistically significant (t =2.33,P =0.01;t =2.18,P =0.02;t =3.44,P =0.00;t =3.09,P =0.00).Muscle relaxation index:The onset time [(98.28 ± 19.97) s],maximum effect duration [(19.97 ± 1.80) s],T1 recovered to 10％ [(26.45 ±0.94) min],T1 recovered from 10％ to 25％ [(13.14 ± 1.12) min],the recovery index[(11.67 ± 0.36) min] in the observation group were better than those in the control group (t =2.57,P =0.01;t =3.11,P =0.00;t =3.127,P =0.00;t =5.23,P =0.00;t =15.31,P =0.00).The tracheal intubation condition of the observation group was superior to that of the control group,but the difference was not statistically significant (P ＞ 0.05).Conclusion There is no statistically significant difference in vital signs between patients with benign and malignant tumors after rocuronium bromide,but the effect of rocuronium bromide on muscle is more sensitive in benign tumor than malignancy,and the onset time and recovery time is shortened.The overall intubation conditions have no significant differences.In the future selection of rocuronium bromide as muscle relaxants in the case of patients with benign and malignant tumors,can choose the appropriate anesthesia,in terms of dose,additional frequency should be considered.

Calculation of left ventricular relaxation time constant Tau in dogs with aortic regurgitation by continuous wave Doppler / 中华医学超声杂志（电子版）

Objective To find a new method for evaluating the left ventricular relaxation time constant Tau with aortic regurgitation by continuous wave Doppler.Methods Twelve Beagle dogs were included in the study.The dog aortic regurgitation model was produced under ultrasound guiding by carotid artery puncture.Aortic pressure was measured by pressure catheter and left ventricular pressure was measured by Millar catheter which was introduced into the left ventricular through cardiac apex.Then microspheres were injected into the left coronary artery under the guidance of ultrasound to induce acute ischemic left ventricular dysfunction,when left ventricular end-diastolic pressure increased more than 5 mmHg (1 mmHg=0.133 kPa).Dobutamine or esmolol was infused to alter left ventricular function.Aortic regurgitation velocity spectrum was recorded by the continuous-wave Doppler echocardiography in different hemodynamic status.At the same time,left ventricular pressure,dp/dt,aortic pressure and continuous ECG tracing were displayed on the multi-channel physiological recorder.Measurement was recorded of-dp/dtmax in the dp/dt tracings and the pressure at the time of-dp/dtmax in the left ventricular pressure tracings.Tau =-P/(dp/dtmax),Tau was the catheter-derived time constant (Taucatheter).Aortic regurgitation spectrum of original audio data was post-processed with MATLAB mathematical software.The spectral lines refresh time of about 300 μs was chosen to form a new Doppler spectrum.Three points:(t1,1 m/s),(t2,2 m/s) and (t3,3 m/s) were selected in aortic regurgitation velocity spectrum and tl,t2 and t3 was put into the corresponding Tau formula:Tau=(t2-t1)/ln[(ADP-C-4)/(ADP-C-16)],Tau=(t3-t1)/ln[(ADP-C-4)/(ADP-C-36)].Tau was the aortic regurgitant time constant (Tauultrasound).The difference between Taucatheter and Tauultrasound was compared by paired t test.The correlation between Taucatheter and Tauultrasound was analyzed by Pearson correlation analysis.Results Twelve dogs were successfully produced aortic regurgitation model.Two dogs died of ventricular fibrillation during the procedure of acute ischemic left ventricular diastolic dysfunction.The range of the Taucatheter was between 27.12 ms and 86.88 ms with an average of (48.973± 14.667) ms;the range of the Tauultrasound was between 28.13 ms and 90.18 ms with an average of (51.236± 15.146) ms.The difference was not statistically significant (t=1.841,P ＞ 0.05).Pearson correlation analysis showed that Taucatheter was positively correlated with Tatultrasound (r=0.89,P=0.000).Conclusion Choosing three points:(t1,1 m/s),(t2,2 m/s) and (t3,3 m/s) in aortic regurgitant velocity spectrum and putting into the corresponding formula,we can calculate Tau,which had a good correlation with the catheter-derived Tau.

Calculation of left ventricular relaxation time constant (Tau) in dogs with mitral regurgitation by continuous-wave Doppler / 中华医学超声杂志（电子版）

Objective To explore the new method for noninvasively measuring the time constant of left ventricular relaxation (Tau) in animals with mitral regurgitation by continuous-wave Doppler.Methods The acute ischaemic left diastolic heart failure with mitral regurgitation was produced in 9 dogs.Dobutamine hydrochloride or esmolol hydrochloride had been applied to change the hemodynamic states.In different hemodynamic states,left ventricular pressures,left atrial pressures,curves of dP/dt and continuous-wave mitral regurgitant spectra were synchronously recorded.Doppler spectra were laterly processed through Matlab workstation.Paired t-test was used to compare the difference between Tau-catheter (Tau-c) and Tau-doppler ultrasound (Tau-d),and the correlation between Tau-c and Tau-d was analyzed by Pearson correlation analysis.Results Thirty-nine hemodynamic status had been obtained in 9 dogs.Tau-c was 21.03-78.45 ms and the average was (48.76± 17.60) ms.Tau-d was 21.24-94.60 ms and the average was (49.33 ± 18.79) ms.There was no significant difference (t=0.353,P=0.726) between Tau-d and Tau-c.The correlation analysis between Tau-d and Tau-c suggested a strong positive relationship with the correlation coefficient (r=0.85,P ＜ 0.001).Conclusions The dog aortic regurgitation model under ultrasound guidance is less traumatic.The method of inducing left ventricular diastolic dysfunction by repeatedly injecting microspheres into the left coronary sinus is safe and reliable.Choosing three points (t1,1 m/s;t2,2 m/s;t3,3 m/s) in aortic regurgitant velocity spectrum and putting them into the corresponding formula,we can obtain Tau,which had a good correlation with the catheter-derived Tau.

Analyze moisture transformation and transport rules during processing of Paeoniae Radix Alba by using low-field NMR / 中国中药杂志

Moisture status and content during the processing of Paeoniae Radix Alba were studied by nuclear magnetic resonance (NMR) and nuclear magnetic resonance imaging (MRI) to investigate the changes of transverse relaxation time (T ₂) and MRI images during boiling and drying processes of Paeoniae Radix Alba. The results showed that water in Paeoniae Radix Alba fresh products was major of free water, and in the boiling process, the content of free water increased whereas the content of bound water declined. At the end of boiling, content of free water reached over 90%. During the drying process, T ₂ moved to the left, and moisture mobility was reduced. The MRI image directly showed that moisture transfer was outside-in process for both increase and decrease. At the end of drying, remaining moisture was mainly present in inner layer of Paeoniae Radix Alba. Quality and appearance were affected by the change of moisture during processing process of medicinal herbs. NMR and MRI could provide direct reference evidence for its moisture changes, and the results of this study could provide direct references and technical support for optimization of processing process of root medicinal materials and evaluation of Chinese herbal pieces.

Estimation of T2* Relaxation Time of Breast Cancer: Correlation with Clinical, Imaging and Pathological Features

OBJECTIVE: The purpose of this study was to estimate the T2* relaxation time in breast cancer, and to evaluate the association between the T2* value with clinical-imaging-pathological features of breast cancer. MATERIALS AND METHODS: Between January 2011 and July 2013, 107 consecutive women with 107 breast cancers underwent multi-echo T2*-weighted imaging on a 3T clinical magnetic resonance imaging system. The Student's t test and one-way analysis of variance were used to compare the T2* values of cancer for different groups, based on the clinical-imaging-pathological features. In addition, multiple linear regression analysis was performed to find independent predictive factors associated with the T2* values. RESULTS: Of the 107 breast cancers, 92 were invasive and 15 were ductal carcinoma in situ (DCIS). The mean T2* value of invasive cancers was significantly longer than that of DCIS (p = 0.029). Signal intensity on T2-weighted imaging (T2WI) and histologic grade of invasive breast cancers showed significant correlation with T2* relaxation time in univariate and multivariate analysis. Breast cancer groups with higher signal intensity on T2WI showed longer T2* relaxation time (p = 0.005). Cancer groups with higher histologic grade showed longer T2* relaxation time (p = 0.017). CONCLUSION: The T2* value is significantly longer in invasive cancer than in DCIS. In invasive cancers, T2* relaxation time is significantly longer in higher histologic grades and high signal intensity on T2WI. Based on these preliminary data, quantitative T2* mapping has the potential to be useful in the characterization of breast cancer.

Dual Component Analysis for In Vivo T₂* Decay of Hyperpolarized ¹³C Metabolites

PURPOSE: To investigate the exchange and redistribution of hyperpolarized ¹³C metabolites between different pools by temporally analyzing the relative fraction of dual T₂* components of hyperpolarized ¹³C metabolites. MATERIALS AND METHODS: A dual exponential decay analysis of T₂* is performed for [1-¹³C] pyruvate and [1-¹³C] lactate using nonspatially resolved dynamic ¹³C MR spectroscopy from mice brains with tumors (n = 3) and without (n = 4) tumors. The values of shorter and longer T₂* components are explored when fitted from averaged spectrum and temporal variations of their fractions. RESULTS: The T₂* values were not significantly different between the tumor and control groups, but the fraction of longer T₂* [1-¹³C] lactate components was more than 10% in the tumor group over that of the controls (P < 0.1). The fraction of shorter T₂* components of [1-¹³C] pyruvate showed an increasing tendency while that of the [1-¹³C] lactate was decreasing over time. The slopes of the changing fraction were steeper for the tumor group than the controls, especially for lactate (P < 0.01). In both pyruvate and lactate, the fraction of the shorter T₂* component was always greater than the longer T₂* component over time. CONCLUSIONS: The exchange and redistribution of pyruvate and lactate between different pools was investigated by dual component analysis of the free induction decay signal from hyperpolarized ¹³C experiments. Tumor and control groups showed differences in their fractions rather than the values of longer and shorter T₂* components. Fraction changing dynamics may provide an aspect for extravasation and membrane transport of pyruvate and lactate, and will be useful to determine the appropriate time window for acquisition of hyperpolarized ¹³C images.

The study of selective segmental renal artery clamping aggravating pathological injury of the solitary-kidney in a porcine model / 中华泌尿外科杂志

Objective To evaluate the effect of selective segmental renal artery clamping ( SSRAC) on the solitary-kidney, providing a foundamental basis for the using of SSRAC in partial nephrectomy. Methods A total of 18 pigs were randomized equally into 2 groups according to the method of renal artery clamping such as main renal artery clamping ( MRAC) group or SSRAC group.Each case underwent right radical nephrectomy and either MRAC or SSRAC for 60 minutes on the left kidney.Serum creatinine ( SCr) and blood urea nitrogen (BUN) were measured before surgery and at 6 time points thereafter (the 1st, 7th, 14th, 21st, 28th, 90th day).Magnetic resonance imaging was performed before surgery and at 4 time points thereafter (the 1st, 7th, 28th, 90th day) and T2 relaxation time and apparent diffusion coefficient (ADC) were determined.Inflammatory cell infiltration and interstitial fibrosis were detected using renal histology on the 1st and 90th day after operation.Results SCr and BUN of the two groups increased to peak value on the 1st day, and then decreased gradually to normal on the 90th day after the operation.On the 1st day, SCr [(266.43 ±31.12)umol/l] and BUN [(13.63 ±2.54)mmol/l)] of SSRAC group were significantly lower than that of MRAC [(386.37 ±40.40)umol/l,(26.83 ±5.96)mmol/l] (P0.05) on the 7th, 14th, 21st, 28th, 90th day.In the MRAC group, the T2 relaxation time of upper, middle and lower pole of the left kidney increased and the ADC decreased on the 1st day after operation.It arrived to the peak value on the 7th day, and decreased or increased respectively from then on to normal level on the 90th day.In the SSRAC group, there were no significant changes of T2 relaxation time and ADC in the upper and middle pole of left kidney (P>0.05), but it was similar to that in the MRAC group for lower pole.On the 1st, 7th, 28th day after operation, the T2 relaxation time of upper and middle pole of the left kidney in the MRAC group [(45.50 ±1.87),(51.82 ±2.27), and(40.37 ±1.93)ms ) ] were significantly higher than those in the SSRAC group [(36.67 ± 1.33),(35.15 ±1.27), and(37.48 ±1.37)ms](P0.05).On the 1st, 7th, 28th day after operation, the ADC of upper and middle pole of the left kidney in the MRAC group [(2.29 ±0.08) ×10 -3 mm2/s, (2.10 ±0.08) ×10 -3 mm2/s, (2.41 ±0.09) ×10 -3 mm2/s] were significantly lower than that of the SSRAC group [(2.69 ± 0.08) ×10 -3 mm2/s, ( 2.63 ±0.06 ) ×10 -3 mm2/s, ( 2.68 ±0.05 ) ×10 -3 mm2/s ] ( P <0.05 ) . However, on the 1st,7th, 28th, 90th day after operation, the ADC of lower pole of the left kidney in the SSRAC group [(1.93 ±0.08) ×10 -3mm2/s,(1.91 ±0.09) ×10-3mm2/s,(2.33 ±0.07) ×10 -3mm2/s, and (2.43 ±0.07) ×10 -3 mm2/s] were significantly lower than those of the MRAC group [ (2.37 ±0.05) ×10 -3 mm2/s, (2.06 ±0.07) ×10 -3 mm2/s, (2.46 ±0.09) ×10 -3 mm2/s, (2.61 ±0.08) ×10 -3 mm2/s](P<0.05).The whole left kidney in MRAC group experienced extensive tubular hydropic degeneration and limited inflammatory cell infiltration on the 1st day after operation.Moreover, renal tubular hydropic degeneration alleviated and no glomerular changes, fibrous tissue hyperplasia or inflammatory cell infiltration was found on the 90th day after operation.In SSRAC group, no changes were found in upper and middle pole of left kidney at the two time points, while the pathological injury of the lower pole of left kidney was more severe.Conclusions SSRAC has obvious protective effect on renal function in the early stage. However, compared with MRAC, the renal tissue injury in the ischemic area was more serious.Therefore, to protect renal function in partial nephrectomy, the ischemic renal area should be reduced as much as possible, even to zero-ischemic, when adopting SSRAC.

Effect of Number of Measurement Points on Accuracy of Muscle T2 Calculations

PURPOSE: The purpose of this study was to investigate the effect of the number of measurement points on the calculation of transverse relaxation time (T2) with a focus on muscle T2. MATERIALS AND METHODS: This study assumed that muscle T2 was comprised of a single component. Two phantom types were measured, 1 each for long (“phantom”) and short T2 (“polyvinyl alcohol gel”). Right calf muscle T2 measurements were conducted in 9 healthy male volunteers using multiple-spin-echo magnetic resonance imaging. For phantoms and muscle (medial gastrocnemius), 5 regions of interests were selected. All region of interest values were expressed as the mean ± standard deviation. The T2 effective signal-ratio characteristics were used as an index to evaluate the magnetic resonance image quality for the calculation of T2 from T2-weighted images. The T2 accuracy was evaluated to determine the T2 reproducibility and the goodness-of-fit from the probability Q. RESULTS: For the phantom and polyvinyl alcohol gel, the standard deviation of the magnetic resonance image signal at each echo time was narrow and mono-exponential, which caused large variations in the muscle T2 decay curves. The T2 effective signal-ratio change varied with T2, with the greatest decreases apparent for a short T2. There were no significant differences in T2 reproducibility when > 3 measurement points were used. There were no significant differences in goodness-of-fit when > 6 measurement points were used. Although the measurement point evaluations were stable when > 3 measurement points were used, calculation of T2 using 4 measurement points had the highest accuracy according to the goodness-of-fit. Even if the number of measurement points was increased, there was little improvement in the probability Q. CONCLUSION: Four measurement points gave excellent reproducibility and goodness-of-fit when muscle T2 was considered mono-exponential.

T2 Relaxation Time Mapping of the Cartilage Cap of Osteochondromas

OBJECTIVE: Our aim was to evaluate the cartilage cap of osteochondromas using T2 maps and to compare these values to those of normal patellar cartilage, from age and gender matched controls. MATERIALS AND METHODS: This study was approved by the Institutional Review Board and request for informed consent was waived. Eleven children (ages 5-17 years) with osteochondromas underwent MR imaging, which included T2-weighted fat suppressed and T2 relaxation time mapping (echo time = 9-99/repetition time = 1500 msec) sequences. Lesion origins were femur (n = 5), tibia (n = 3), fibula (n = 2), and scapula (n = 1). Signal intensity of the cartilage cap, thickness, mean T2 relaxation times, and T2 spatial variation (mean T2 relaxation times as a function of distance) were evaluated. Findings were compared to those of patellar cartilage from a group of age and gender matched subjects. RESULTS: The cartilage caps showed a fluid-like high T2 signal, with mean thickness of 4.8 mm. The mean value of mean T2 relaxation times of the osteochondromas was 264.0 +/- 80.4 msec (range, 151.0-366.0 msec). Mean T2 relaxation times were significantly longer than the values from patellar cartilage (39.0 msec) (p < 0.0001). These findings were observed with T2 spatial variation plots across the entire distance of the cartilage cap, with the most pronounced difference in the middle section of the cartilage. CONCLUSION: Longer T2 relaxation times of the cartilage caps of osteochondromas should be considered as normal, and likely to reflect an increased water content, different microstructure and component.

Xylanase activity and T2 (MRI) relationship during lulo la selva P32 ripening process / Relación entre la actividad de la xilanasa con medidas del T2 (IRM) durante el proceso de maduración del lulo La Selva P32 / Relação entre e atividade com as medidas xilanase T2 (IRM) durante a maturação lulo A Selva P32

The lulo La Selva P32 is a cross over different kinds of lulo. Though its sensory characteristics improvement, its life span is very short. Due to it is a new kind of lulo, there are not so many studies over the ripening process. In order to understand some softening processes, in this work it is evaluated the xylanase kinetics at the lulo peel during ripening, and the results are correlated with the MRI (Magnetic Resonance Imaging) relaxation time T2 . During ripening time, it is observed that the xylanase is one of the enzymes involved in the hydrolysis of the cell wall polymers. In addition, two T2 values regimes were distinguished by the xylanase kinetics. Although the correlation coefficient of 0.82 and p = 0.024 values, the results suggest that T2 weighted MRI can be useful as a non-invasive tool for ripening process monitoring.

El Lulo La Selva P32 es un fruto producto del entrecruzamiento de varias especies de lulo. Aunque tiene mejores características organolépticas, su vida útil es corta. Dado que se trata de una variedad relativamente nueva de lulo, no hay muchos estudios sobre su proceso de maduración. En este trabajo, con el fin de entender algunos de los procesos de ablandamiento de esta variedad de lulo, por una parte, se evalúa la cinética de la xilanasa en la corteza durante la maduración y, por otra parte, estos resultados se correlacionan con el tiempo de relajación T2 , de la Imágenes de Resonancia Magnética Nuclear (IRM). Durante la maduración se observó que la xilanasa es una de las enzimas involucradas en la hidrólisis de los polímeros de la pared celular. Además, a partir de los resultados de la cinética de la xilanasa, se pudieron distinguir dos regímenes de valores T2 . Aunque el coeficiente de correlación fue de 0.82 y p = 0.024, los resultados sugieren que la determinación de T2 por medio de IRM se puede utilizar como una herramienta no invasiva en el proceso de monitoreo de maduración.

O Lulo La Selva P32 é um produto fruto do cruzamento de várias espécies de lulo com um tempo de vida útil curto. Existem poucos estudos para entender os mecanismos que influenciam o amolecimento no lulillo. Este artigo se relaciona com a atividade da xilanase na casca do lulillo com a mobilidade das águas livres (tempo de relaxamento T2 ). O T2 se quantificou por imagens de ressonáncia magnética e a atividade da xilanase por métodos bioquímicos. Se observou uma tendencia no comportamiento dos valores do T2 na mobilidade das águas livres semelhantes á atividade da xilanase, associando-se a migração da água desde o exterior do fruto pela ação da enzima, involucrada na hidrólise de polímeros da parede celular. Apesar do coeficiente de correlação (0.82) e do p (0.024), os resultados sugerem que as imagens de ressonáncia poderiam ser uma alternativa nao destrutiva na indústria de exportação, visto que permite determinar o início da senescencia do fruto, baseado em condições fisiológicas e bioquímicas.

Detección del receptor de factor de crecimiento epidérmico en lesiones orales premalignas por relaxometría / Detection of the epidermal growth factor receptor by relaxometry of oral premalignant lesions

OBJETIVO: detectar la sobreexpresión del receptor de factor de crecimiento epidérmico en células epiteliales de lesiones premalignas de la mucosa bucal, marcadas magnéticamente por relaxometría. MÉTODOS: las células exfoliadas de mucosa oral de individuos sanos y enfermos se marcaron con el sistema: IgG anti-EGF-R biotinilada/IgG anti-biotina conjugada con partículas superparamagnéticas y se midieron los tiempos de relajación T1 y T2. RESULTADOS: disminuyeron los tiempos de relajación (T1 y T2) de las células marcadas respecto a las no marcadas, en todas las muestras analizadas. Al comparar los valores de T1 y T2 de las células marcadas de la lesión con los valores de las células sanas, se encontró una disminución estadísticamente significativas del tiempo de relajación. Al comparar los tiempos de relajación de células marcadas sanas con los de las células de las diferentes lesiones encontramos diferencias estadísticamente significativas para los casos de células de leucoplasias y liquen plano tanto en T1 como T2; no así con células de queratosis. CONCLUSIONES: los resultados muestran que es posible detectar por relaxometría células que expresen el receptor de factor de crecimiento epidérmico, utilizando el sistema conjugado empleado y que el EGF-R se sobreexpresa en células de lesiones como leucoplasia y liquen plano.

OBJECTIVE: Detect the overexpression of the epidermal growth factor receptor in epithelial cells of premalignant lesions of the oral mucosa magnetically marked by relaxometry. METHODS: Exfoliated oral mucosa cells from healthy and sick individuals were marked with the system biotinylated anti-EGF-R IgG / anti-biotin IgG conjugated with supermagnetic particles and measurements were taken of relaxation times T1 and T2. RESULTS: In all the samples analyzed there was a decrease in the relaxation times (T1 and T2) of marked cells with respect to unmarked cells. Comparison of the T1 and T2 values of marked cells from the lesion with the values of healthy cells revealed a statistically significant decrease in relaxation time. Comparison of the relaxation times of healthy marked cells with those of cells from the various lesions revealed statistically significant differences in both T1 and T2 in cells from lichen planus and leukoplakias, but not in cells from keratoses. CONCLUSIONS: Results show that relaxometry may be used to detect cells expressing the epidermal growth factor receptor, using the conjugated system described herein, and that EGF-R is overexpressed in cells from lesions such as leukoplakia and lichen planus.

Effect of pre-fatigue method by leg extension exercise on recruitment state of synergists in thigh muscles during leg press exercise / 体力科学

The purpose of this study was to examine the recruitment state of synergistic muscles in the thigh muscles in leg press exercise with and without pre-fatigue method using transverse relaxation time (T2) on muscle functional magnetic resonance imaging (MRI). Nine healthy male subjects performed the following two types of exercise trials on separate days: 1) 5 sets of a leg press exercise with pre-fatigue method, which consisted of 3 sets of knee extension exercise (LP-pre), 2) 5 sets of a leg press exercise without pre-fatigue method (LP). Both exercises were performed at a load of 80% one-repetition maximum. Before and immediately after exercise, T2-weighted MR images of right-thigh were taken to calculate T2 values of twelve-thigh muscles. The T2 values for quadriceps femoris muscle and hamstrings in LP increased significantly after the exercise, except in the adductor magnus, adductor longus, gracilis, and sartorius. In contrast, the T2 values for all of the twelve-thigh muscles in LP-pre increased significantly after the exercise. Upon comparison between the two trials, the percentage changes in T2 value for the adductor magnus, adductor longus, and sartorius in LP-pre were found to be significantly greater than those in LP. These results suggest leg press exercise with pre-fatigue method may be effective to increase activity of synergistic muscles in thigh muscles during exercise.

Characterization of water distribution and activities of enzymes during germination in magnetically-exposed maize (Zea mays L) seeds.

Magnetic seed treatment is one of the physical pre-sowing seed treatments to enhance the performance of crop plants. In our earlier experiment, we found significant increase in germination and vigour characteristics of maize (Zea mays L.) seeds subjected to magnetic fields. Among various combinations of magnetic field (MF) strength and duration, best results were obtained with MF of 100 mT for 2 h and 200 mT for 1 h exposure. The quicker germination in magnetically-exposed seeds might be due to greater activities of germination related enzymes, early hydration of membranes as well as greater molecular mobility of bulk and hydration water fractions. Thus, in the present study, changes in water uptake during imbibition and its distribution and activities of germinating enzymes during germination were investigated in maize seeds exposed to static magnetic fields of 100 and 200 mT for 2 and 1 h respectively by nuclear magnetic resonance (NMR) spectroscopy. The magnetically-exposed seed showed higher water uptake in phase II and III than unexposed seed. The longitudinal relaxation time T1 of seed water showed significantly higher values and hence greater molecular mobility of cellular water in magnetically-exposed seeds as compared to unexposed. Component analysis of T2 relaxation times revealed the early appearance of hydration water with least mobility and higher values of relaxation times of cytoplasmic bulk water and hydration water in magnetically-exposed over unexposed seeds. Activities of -amylase, dehydorgenase and protease during germination were higher in magnetically-exposed seeds as compared to unexposed. The quicker germination in magnetically-exposed seeds might be due to greater activities of germination related enzymes, early hydration of membranes as well as greater molecular mobility of bulk and hydration water fractions.

Quantitative Assessment of the T2 Relaxation Time of the Gluteus Muscles in Children with Duchenne Muscular Dystrophy: a Comparative Study Before and After Steroid Treatment

OBJECTIVE: To determine the feasibility of using T2 mapping as a quantitative method to longitudinally follow the disease activity in children with Duchenne muscular dystrophy (DMD) who are treated with steroids. MATERIALS AND METHODS: Eleven boys with DMD (age range: 5-14 years) underwent evaluation with the clinical functional score (CFS), and conventional pelvic MRI and T2 mapping before and during steroid therapy. The gluteus muscle inflammation and fatty infiltration were evaluated on conventional MRI. The histograms and mean T2 relaxation times were obtained from the T2 maps. The CFS, the conventional MRI findings and the T2 values were compared before and during steroid therapy. RESULTS: None of the patients showed interval change of their CFSs. On conventional MRI, none of the images showed muscle inflammation. During steroid treatment, two boys showed increased fatty infiltration on conventional MRI, and both had an increase of the mean T2 relaxation time (p < 0.05). The remaining nine boys had no increase in fatty infiltration. Of these, three showed an increased mean T2 relaxation time (p < 0.05), two showed no change and four showed a decreased mean T2 relaxation time (p < 0.05). CONCLUSION: T2 mapping is a feasible technique to evaluate the longitudinal muscle changes in those children who receive steroid therapy for DMD. The differences of the mean T2 relaxation time may reflect alterations in disease activity, and even when the conventional MRI and CFS remain stable.

Comparison of Proton T1 and T2 Relaxation Times of Cerebral Metabolites between 1.5T and 3.0T MRI using a Phantom

PURPOSE: To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T. MATERIALS AND METHODS: Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T. RESULTS: The T1 relaxation times of NAA were 2293 +/- 48 ms at 1.5T and 2559 +/- 124 ms at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were 2540 +/- 57 ms at 1.5T and 2644 +/- 76 ms at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were 2543 +/- 75 ms at 1.5T and 2665 +/- 94 ms at 3.0T (4.8% increase). The T2 relaxation times of NAA were 526 +/- 81 ms at 1.5T and 468 +/- 74 ms at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were 220 +/- 44ms at 1.5T and 182 +/- 35 ms at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were 289 +/- 47 ms at 1.5T and 275 +/- 57 ms at 3.0T (4.8% decrease at 3.0T). CONCLUSION: The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.