MRI findings in injured articular cartilage of the knee correlated with surgical findings / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There is a strong need for quick noninvasive diagnostic technique that can give a valid estimate of the status of the cartilage reliably, discriminating intact cartilage from various grades of impaired cartilage. The goal of this study was to assess the incidence of knee cartilage injuries and compare the accuracy of two-dimension spin echo (2D SE) and fast spin echo (FSE) (conventional MRI), three-dimensional spoiled gradient echo (3D SPGR), three-dimensional fast imaging employing steady state acquisition (3D FIESTA) MR imaging sequences with surgical examination of the articular cartilage.</p><p><b>METHODS</b>One hundred and thirty-eight knees with history of knee trauma received conventional MRI, 3D SPGR and 3D FIESTA MRI examination before surgery, and surgical examination of articular cartilage was used as reference standard. A modified version of the Noyes classification system was applied for the evaluation of the lateral femoral condyle (LFC), medial femoral condyle (MFC), lateral tibial plateau (LTP), medial tibial plateau (MTP), trochlea and patella. The incidence and distributions of different injured grades at different articular surfaces of knee were assessed. A series of assessment indeces of 3D SPGR, 3D FIESTA, and the combination of the conventional MRI and 3D SPGR imaging were calculated.</p><p><b>RESULTS</b>The incidence of cartilage defects (grade 2 to 4) was 22% (183/828), according to surgical examination. Grade 3 and 4 lesions were absent at the medial tibial plateau. The rates of exact match between the grading results of different MRI procedures and surgical examination were 49% of 3D SPGR, 61% of 3D FIESTA, and 82% of the combination of 3D SPGR and conventional MRI. Also, the combination of 3D SPGR and conventional MR imaging provided the highest sensitivity, specificity, accuracy, positive and negative predictive values, at 71%, 97%, 90%, 90% and 90%, respectively.</p><p><b>CONCLUSIONS</b>For all the articular surfaces of the traumatic knees, about one fifth (22%) were cartilage defects. Both 3D SPGR and 3D FIESTA imaging performed similarly in detecting cartilage lesions of the knee. The increased accuracy in chondral assessment can be achieved by combining 3D SPGR and conventional MRI within a reasonable time.</p>

Magnetic resonance susceptibility weighted imaging in detecting intracranial calcification and hemorrhage / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Computed tomography (CT) is better than routine magnetic resonance imaging (MRI) in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging (SWI) in the detection and differentiation of intracranial calcification and hemorrhage.</p><p><b>METHODS</b>Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift (PS) of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically.</p><p><b>RESULTS</b>The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT (P > 0.05). There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was +0.734 +/- 0.073 and -0.112 +/- 0.032 respectively (P < 0.05). The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.</p><p><b>CONCLUSIONS</b>SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.</p>

Evaluation of whole body MRI and diffusion-weighted MRI in detecting intranodal lesions in patients with lymphoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the whole body MRI and diffusion-weighted MRI in detecting intranodal lesions in patients with lymphoma.</p><p><b>METHODS</b>Whole body MRI and diffusion-weighted MRI (DWI) were performed in 23 patients with histologically proven lymphoma. A conventional coronal MRI scan from head to inguinal groove was done for whole body scanning. In the DWI, axial MRI scans were performed after segmentation based on SENSE technique, and all images were merged into whole body image reconstruction by software.</p><p><b>RESULTS</b>417 lymph nodes were detected by MRI in the 23 patients. The overall positive rate of whole body MRI and DWI was 79.1% and 89.7%, respectively. It was 70.9% versus 85.2% and 79.4% versus 90.1% for the lymph nodes of < 2 cm and 2-3 cm in diameter, with a significant difference between the two methods (P < 0.01). However, it was 94.7% versus 97.9% for the lymph nodes of > 3 cm in diameter, not significantly different between the two methods (P > 0.05). Both methods had similar sensitivity in detecting the lymph nodes in the neck, supraclavicular and infraclavicular fossae, mediastinum and axillary fossa. However, the positive rate of whole body MRI was 51.2%, 43.8% and 52.2%, significantly less sensitive than 83.7%, 71.9% and 87.0%, respectively, by DWI in detecting the lymph nodes in the retroperitoneal space, pelvic cavity and inguinal groove (all P < 0.01).</p><p><b>CONCLUSION</b>Both whole body MRI and diffusion-weighted MRI have a relative high sensitivity in detecting intranodal lesions for patients with lymphoma, showing a certain value in clinical application.</p>

Correlation between magnetic resonance diffusion weighted imaging and cell density in astrocytoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the apparent diffusion coefficients (ADC) in magnetic resonance diffusion weighted imaging with echo-planar technique in depicting the tumor cellularity and grading of astrocytoma.</p><p><b>METHODS</b>Thirty-four astrocytoma patients including 18 male and 16 female with age from 10 to 73 years (mean 38.4 years) were examined by MRI and eventually proved by surgical resection and pathological examination. Of them, 26 had low-grade (grade I, II) astrocytoma and 8 high-grade (grade III, IV) astrocytoma. ADC value of astrocytoma was determined on magnetic resonance diffusion weighted images. Cellularity of the astrocytoma was analyzed using Adobe Photoshop 7.0.1 software.</p><p><b>RESULTS</b>The mean ADC value (in units of 10(-4) mm(2)/s) of the high-grade astrocytomas (7.34 +/- 2.95) was significantly lower than that of the low-grade astrocytomas (13.76 +/- 3.31) (t = 4.91, P < 0.001). The mean cellularity of the high-grade astrocytomas (19.81 +/- 9.73)% was significantly higher than that of the low-grade astrocytomas (4.74 +/- 2.96)% (t = 4.32, P = 0.003). ADC value of the astrocytoma was significantly and negatively correlated with its cellularity (r = -0.535, P = 0.001).</p><p><b>CONCLUSION</b>ADC value of astrocytoma is significantly and negatively correlated with its cellularity. Magnetic resonance diffusion weighted imaging may well be highly potential in predicting the degree of astrocytoma.</p>

1H-MRS of the hippocampus of psychogenic erectile dysfunction / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the changes of the hippocampus metabolites with MRS to provide some clues for exploring the possible underlying unrecognised factors and pathophysiological mechanisms of psychogenic erectile dysfunction (ED).</p><p><b>METHODS</b>Fifteen cases of psychogenic erectile dysfunction and 15 normal volunteers (the control) were studied by a clinical 1. 5T MRI/MRS system. Proton multi-voxel spectroscopy imaging (1H-MRSI) was obtained from both sides of the hippocampus region. N-acetylaspartate (NAA), creatine and phosphocreatine (Cr) and choline-containing compounds (Cho) were determined and the ratios of NAA/Cr and Cho/Cr were calculated respectively.</p><p><b>RESULTS</b>The NAA/Cr ratio was significantly lower in the ED patients than in the control (P < 0.05). There was no significant difference in the Cho/Cr ratio between the two groups (P > 0.05).</p><p><b>CONCLUSION</b>Psychogenic erectile dysfunction may not be simply a functional disease. The hippocampus may be involved in the pathophysiology of psychogenic ED. The disease may have some previously unrecognised underlying aetiological factors and pathophysiological mechanisms.</p>

Xylitol production from corn cob hemicellulosic hydrolysate by Candida sp / 生物工程学报

Xylitol, a five-carbon sugar alcohol, has many interesting applications in the food, pharmaceutical, and odontological industries, owing to its high sweetening power, its anticariogenic properties, and its insulin-independent metabolism. The bioconversion of detoxified hemicellulosic hydrolysate to xylitol by microorganisms could be a cheaper alternative to the current chemical process, since it is a simple process, with great specificity and low energy requirements. However, the success of fermentations for xylitol production depends on the productivity of the strain and its tolerance to different toxic or inhibitory compounds existing in the hydrolysates. In addition, a number of culture process parameters proved to have significant effects on xylitol production in hemicellulosic hydrolysate media. One of the most important control variables in this bioconversion is the aeration level, which affects the biochemical pathways in the xylose metabolism. The production of biomass is favored by aerobic conditions, while under anaerobic conditions xylose cannot be assimilated by yeast, whereas xylitol is formed in oxygen-limited incubation conditions. An adapted Candida sp. with enhanced resistance to the inhibitors in the hydrolysate can directly ferment the simply detoxified corn cob hemicellulosic hydrolysate to xylitol. In the present study, the combined effects of shaking speed, C/ N ratio, initial pH, and inoculum level on the fermentation of corn cob hemicellulosic hydrolysate to xylitol by an adapted Candida sp. were investigated using an orthogonal experimental design in flask. As a result, the optimum fermentation conditions were as follows: 180 r/min, a C/N ratio of 50, initial pH 5.5, and an inoculum level of 5% (volume ratio). Moreover, the optimum concentration factor of hydrolysate varied between 3.0 and 3.72 was obtained. Based on these results, in order to evaluate the effect of aeration rate on the fermentation of corn cob hemicellulosic hydrolysate to xylitol in fermentor, batch fermentations were carried out in a 3.7 L stirred fermentor using four different aeration strategies, including three kind of two-stage aeration strategies, which provided relatively high aeration rate in the early stage but reduced it in the later stage, and including a one-stage aeration strategy provided a constant aeration rate. With respect to xylitol yield, the results indicated that two-stage aeration strategy was significantly superior to one-stage aeration strategy. The highest xylitol yield (0.75 g/g) was obtained with oxygen supply strategy C (3.75 L/min for first 24 h, then lowered it to 1.25 L/min, 2.5 L fermentation medium was employed). In this process, without extensive detoxification of hydrolysate, an adapted Candida sp. can efficiently ferment the simply treated corn cob hemicellulosic hydrolysate to xylitol under the optimized fermentation conditions. This work should help the development of an efficient process for producing xylitol from corn cob hemicellulosic hydrolysate on a larger scale by bioconversion.

Studies on immobilized cellobiase / 生物工程学报

Cellulosic material is the most abundant renewable carbon source in the world. Cellulose may be hydrolyzed using cellulase to produce glucose, which can be used for production of ethanol, organic acids, and other chemicals. Cellulase is a complex enzyme containing endoglucanase (EC 3.2.1.4), exoglucanase (EC 3.2.1.91) and cellobiase (EC 3.2.1.21). The hydrolysis of natural cellulose to glucose depends on the synergism of these three components. The mostly used cellulase produced by Trichoderma reesei has high activity of endoglucanase and exoglucanase, but the activity of cellobiase is relatively low. Therefore, improving the activity of cellobiase in cellulase reaction system is the key to enhance the sacchrification yield of cellulosic resources. Aspergillus niger LORRE 012 was a high productivity strain for cellobiase production. It was found that the spores of this strain were rich in cellobiase. In this work, the cellobiase was immobilized efficiently by simply entrapping the spores into calcium alginate gels instead of immobilizing the pure cellobiase proteins. The immobilized cellobiase was quite stable, and its half-life was 38 days under pH 4.8, 50 degrees C. The thermal stability of the immobilized cellobiase was improved, and it was stable below 70 degrees C. The suitable pH range of the immobilized cellobiase was pH 3.0 - 5.0, with the optimal pH value 4.8. The Km and Vmax value of the immobilized cellobiase were 6.01 mmol/L and 7.06 mmol/min x L, respectively. In repeated batch hydrolysis processes, 50 mL of substrate (10 g/L cellobiose) and 10 mL of immobilized beads containing cellobiase were added into a 150 ml flask. After reacting at pH 4.8, 50 degrees C for several hours, the hydrolysate was harvested for assay, and the immobilized beads were used for the next batch hydrolysis with the fresh substrate. This process was repeated, and the yield of enzymatic hydrolysis kept higher than 97% during 10 batches. The continuous hydrolysis process was carried out in a column reactor (inside diameter 2.8 cm, inside height 40 cm) packed with the immobilized beads. Using 10 g/L cellobiose as substrate, the hydrolysis yield reached 98% under 0.4 h (-1) dilution rate and pH 4.8, 50 degrees C. After corncob was treated by 1% dilute acid, the cellulosic residue (100 g/L) was used as substrate, and hydrolyzed by the cellulase (15 IFPU/g substrate) from Trichoderma reesei, at pH 4.8, 50 degrees C for 48 h. The concentration of reducing sugar in the hydrolysate was only 48.50 g/L (hydrolysis yield 69.5%). When the hydrolysate was further treated by the immobilized cellobiase, the cellobiose was hydrolyzed into glucose, and the feedback inhibition caused by the cellobiose accumulation disappeared sharply. By the synergism of immobilized cellobiase and the cellulase from T. reesei left in the hydrolysate, other oligosaccharides were mostly converted to monosaccharides. At 48 h, the reducing sugar concentration was increased to 58.78 g/L, the hydrolysis yield of the corncob residue was improved to 84.2%, and the ratio of the glucose in the total reducing sugar was increased from 53.6% to 89.5%. The reducing sugars converted from corncob could be used further in the fermentation of valuable industrial products. This research results were meaningful in the conversion and utilization of renewable biomass.

Comparative study between MRI and echocardiography in noncompaction of ventricular myocardium / 中华放射学杂志

Objective To investigate the MRI and echocardiography manifestations of noncompaction of ventricular myocardium(NVM)and assess the role of MRI in the diagnosis of NVM by comparing it with echocardiography.Methods Fourteen cases of NVM diagnosed by echocardiography were examined with MRI,including scanning of black-blood sequences,double inversion recovery fast spin echo (DIRFSE)and triple inversion recovery fast spin echo(TIRFSE),and white blood sequence:fast imaging employ steady state acquisition(FIESTA).Scanning plane includes short axis view,four-chamber view and long axis view.Results Both MRI and echocardiography displayed involvement of left ventricles in thirteen cases and involvement of double ventricles in one case.Apexes of heart and the intermedius are commonly affected.MRI showed 54 segments and echocardiography showed 53 segments affected,and there is no significant difference between the capability of MRI and echocardiography(P=1.000).The affected myocardium consisted of two layers:subendoeardial noncompacted myocardium and epicardial compacted myocardium,and the ratio measurement of N/C by MRI was 3.37?0.89 and it was 3.19?0.82 by echocardiography.Noncompacted myocardium was characterized by prominent and excessive myocardial trabeculations and deep intratrabecular recesses,in which the blood flow was communicated with the ventricle.One case was complicated with ventricular aneurysm,and coronary arteriography was performed with unremarkable findings.One case underwent heart transplantation because of progressive heart failure, Gross findings demonstrated prominent muscular trabeculations with deep intratrabecular recesses,which coincided well with MRI findings.Conclusion The MRI manifestation of NVM is characteristic,and MRI with multiple series and planes is helpful in the diagnose of NVM.Compared with echoeardiography,MRI could display the pathological cardiac muscle more clearly,because of its high soft-tissue resolution and spatial resolution.

Congenital cystic adenomatoid malformation of fetus:manifestations and diagnosis of MRI / 中华放射学杂志

Objective To demonstrate the MRI manifestations of congenital cystic adenomatoid malformation(CCAM)and to evaluate the diagnostic value of MRI.Methods Thoracic axial,sagittal and coronal plane scanning were performed with SSFSE in 9 fetuses diagnosed or suspected of CCAM by ultrasound(US)within 1—2 days after US examination.The diagnosis was confirmed by postnatal autopsy or follow-up.Results In nine fetuses,seven cases of CCAM were diagnosed with MRI and confirmed by autopsy,one case was congenital pulmonary sequestration,one was normal on MRI and two weeks late US.In seven cases of CCAM(5 males and 2 females),four cases were in the right side,three in the left.Four cases of macrocystic type CCAM showed single or multiple cystic long T_2 signal in the unilateral lung,three cases of microcystic type CCAM presented long T_2 signal without cyst.Vessels with flow void phenomenon were found in 2 cases of CCAM and 1 case of pulmonary sequestration.Conclusion MRI can clearly show the location,range and contour of CCAM.The vessel originated from the aorta is suggestive of pulmonary sequestration.

Correlation study between MR spectroscopic findings and cell proliferation in astrocytoma / 中华放射学杂志

Objective To investigate the relationship between findings of proton magnetic resonance spectroscopy(~1H-MRS)and tumor proliferative potential in patents with astrocytoma.Methods Thirty four patients of astrocytomas proved by surgery and pathology were examined by MRI and ~1H-MRS,among them 26 were of grade Ⅰ or Ⅱ(low grade)and 8 of grade Ⅲ or Ⅳ(high grade).Twenty one eases of astrocytomas(17 low-grade and 4 high grade respectively)were homogeneous type.Expression of proliferating cell nuclear antigen(PCNA)was detected by immunohistochemical method of streptavidin- biotin-peroxidase(SP).Results The Cho/NAA and Cho/Cr ratios of high-grade astrocytomas(M=4.895, 4.845 respectively)were significantly higher than those of low-grade astrocytomas(M=2.920, 2.000 respectively)in the 21 homogeneous astrocytomas(Z=-2.597,P=0.009;Z=-2.687,P= 0.007 respectively),and the ratios were found to be significantly correlated to the expression of PCNA(A= 7.880)(r=0.607,P=0.003;r=0.457,P=0.038 respectively).However,the differences of Cho/NAA、 Cho/Cr ratios between the high-grade and low-grade astrocytomas were not significant when 34 cases were included,and no relationship was found between Cho/NAA(M=3.965,2.890 respectively)、Cho/Cr(M= 3.080、1.960 respectively)ratios and the expression of PCNA(A=8.100)(r=0.060,P=0.738;r= 0.125,P=0.480 respectively).Conclusion By measuring the Cho/NAA and Cho/Cr ratios,~1 H-MRS may be a valuable method for presurgical in invo prediction of the malignant degree,tumor proliferative potential and prognosis of homogeneous-type astrocytomas.

Clinical application of MR diffusion tensor imaging in lumbar disc annulus fibrosus / 中华放射学杂志

0.05).Seven cases in LDH group and 9 cases in HID group were found in FT picture.The mean DCavg value in annulus fibrosus disruption was significantly larger (1.01?0.10)?10~(-9)mm~2/s and the mean FA value(0.15?0.03)was significantly smaller than those in normal place(P

Proton MR spectroscopy study in neonates with hypoxic ischemic encephalopathy / 中华放射学杂志

Objective To investigate the metabolic alterations in the brain of neonates with HIE and correlate those alterations with clinical grading and prognosis of HIE.Methods Fourty-six eases of full-term neonates diagnosed as HIE clinically were performed MRI and 1~H-MRS,9 healthy neonates without the evidence of asphyxia were studied as controls,1~H-MRS techniques included single voxel proton MRS and two dimensional muhi-voxel chemical shift spectroscopy imaging,point resolved spectroscopy sequence was used for 1~H-MRS.Metabolic changes in the spectroscopy were analyzed in neonates with HIE,and study the relationgship between MRS findings and prognosis.Results(1)The typical 1~H-MRS manifestations of full- term neonates suffering from HIE were as follows:the peaks of Lac were elevated,GLx-? were elevated and NAA were decreased.(2)GLx-?/Cr ratio in control,mild,moderate and severe HIE group was 0.16, 0.21,0.64,and 1.31,respectively.Lac/Cr ratio in control,mild,moderate and severe HIE group was 0.12,0.14,0.19,and 0.26,respectively.There was a significant difference in the ratio of GLx-? and Lac/Cr between HIE group and control group(t=5.01,P