Objective To prospectively evaluate the value of diffusion-weighted imaging with background signal suppression (DWIBS) in the detection and diagnoses of metastatic cervical lymph nodes. Methods Twenty patients with head and neck squamous cell carcinomas underwent conventional MRI and DWIBS. The ADC values were measured and compared between metastatic and benign lymph nodes. The abilities of DWIBS and conventional MRI in the evaluation of metastatic cervical lymph nodes were compared. Results Conventional MRI demonstrated 101 lymph nodes, in which 58 were diagnosed as metastatic nodes. When MRI criteria were used for discrimination between metastatic and benign nodes, the obtained sensitivity, specificity, accuracy, positive and negative predictive value were 78% (47/60), 81%(44/54), 80% (91/114), 82% (47/57) and 77% (44/57), respectively. The mean ADC values of metastatic nodes (n =60) and benign nodes (n =54) were (0.945 ±0.122) × 10-3 mm2/s and (1. 210 ±0. 151 ) × 10-3 mm2/s ( t = - 10. 354 ,P ＜0. 01 ). When an ADC value of 1. 090 × 10 -3 mm2/s was used as the threshold for discrimination between metastatic and benign nodes, the obtained sensitivity, specificity,accuracy, positive and negative predictive value were 88% (53/60), 80% (43/54), 84% (96/114), 83%(53/64) and 86% (43/50), respectively. Conclusion DWIBS is helpful in diagnosing metastatic cervical lymph nodes of head and neck squamous cell carcinoma, and is superior to conventional MRI in their detection.

Objective To evaluate the correlation between MRI and X-Ray discography findings and pain response at provocative discography in patients with discogenic back pain. Methods Two hundred and fifty-six lumbar intervertebral discs in 93 patients who underwent MRI and X-Ray discography were included in this study. MR images were retrospectively evaluated regarding disc degeneration, endplate abnormalities and high intensity zone. Disc degeneration was graded according to the modified criteria of Pearce, et el. Evaluation of disc morphology was performed with X-Ray discography by using the classification of Adams, et al. Endplates and adjacent bone marrow abnormalities were classified according to Modic,et al. During discography concordant pain was regarded as positive, whereas discordant pain and no pain were regarded as negative. The data were analyzed using the Chi-squnre test. Results There were 116 discs with concordant pain and 140 discs with discordant pain or no pain. Of 256 discs on discography, 17 discs were type Ⅰ17(6.6%),type Ⅱ were 25(9.8%),type Ⅲ were 91(35.5%), type Ⅳ were 77(30.1%) and type Ⅴ were 46(18.0% ). On MR images, discs of grade Ⅰ were 23 (9.0%) ,grade Ⅱ were 34(13.3%), grade Ⅲ were 84(32.8%), grade Ⅳ were 85 (33.2%) and grade Ⅴ were 30(11.7%). There was positive correlation between Pearce graded of MRI and classification of Adams of discography (r=0.62, X2 =160.87,P <0.01).In 123 discs of type Ⅳ to type Ⅴ on discography, 104 discs were with concordant pain. There was positive correlation between type Ⅳ-Ⅴ and concordant pain( r=0.60, X2 = 144.08, P < 0.01). In 115 discs of Ⅳ-Ⅴ grade degeneration, 99 discs presented with concordant pain. There was positive correlation between Ⅳ-Ⅴ grade disc degeneration and concordant作者单位:510120 广州,中山大学附属第二医院放射科 pain(r = 0.59, X2 = 137.11, P <0.01 ). In 60 discs with high intensity zone(HIZ), 52 discs presented with concordant pain. There was positive correlation between HIZ and concordant pain ( r=0.41, X2= 51.93, P <0.01 ). In 58 discs with endplate degeneration, 51 presented with concordant pain. There was positive correlation between Modic degeneration and concordant pain ( r = 0.41, X2= 52.76, P < 0.01 ). Conclusion In patients with chronic low back pain, MR imaging may present moderate to severe disc degeneration, high intensity zone, endplates and adjacent bone marrow abnormalities. MR findings with concordant pain can raise the diagnostic possibility of discogenic lumbar pain. Typical discography findings, fissured or ruptured disc, with concordant pain are important diagnostic evidence for discogenic lumbar pain.

AIM: Tyrosinase gene was transfected into HEK293 cell as a reporter gene, it's property of synthesizing melanin, which can be examined by magnetic resonance imaging(MRI), is used to evaluate the tyrosinase gene's expression. The aim of this study was to search a way to evaluate the results of gene expression by MRI in vitro .METHODS: The plasmid of pcDNA3tyr which carried the full-length cDNA of tyrosinase gene was transfected into HEK293 cell by lipofectin. To observe the MRI signals of expressed melanin,the transfected cells were scanned by MRI sequences of T 1WI, T 1WI/SPIR and T 2WI. On the other hand, fontana stain was used to search for melanin granules in transfected cells, RT-PCR method was used to search for cDNA of tyrosinase gene. RESULTS: (1) Plasmids of pcDNA3tyr could be transfected into HEK293 cells and could synthesize a large amount of melanin. The synthetic melanins of 10 6 cells, which had been transfected 5?g, 10?g, 20?g plasmids of pcDNA3tyr separately, were all sufficient to be detected by MRI and appeared high signal in MRI T 1WI、T 1WI/SPIR、T 2WI sequences. The signal intensities of MRI imaging were related to the amounts of transfected plasmids positively. (2) The melanin granules could be found in HEK293 cells by Fontana stain. (3) The cDNA fragment of tyrosinase gene could be detected in transfected HEK293 cells by RT-PCR. CONCLUSION: The fact that MRI could detect the synthetic melanin of HEK293 cells, which controlled by expression of exogenous gene, demonstrates that medical imaging connecting with molecular biology technology can evaluate the result of gene expression in vitro .

Objective To observe the effect of puerarin on the ICAM-1 gene expression in streptozotocin-Induced diabetic nephropathy rats. Methods Diabetic nephropathy rats were induced by intraperitoneal injection of STZ.Rats were allocated into normal control group,model group,and puerarin group.The puerarin treatment lasted for 16 weeks.During and after the treatment,the general health conditions,blood glucose levels,blood urea nitrogen,serum creatinine,urinary albumin excretion rate of 24-hours,and clearance rate of creatinine of the rats were observed.The ICAM-1mRNA expressions were also determined by in situ hybridization analysis in the kidney tissue of the rats.Results Diabetes mellitus and renal function lesion occurred in the model group and puerarin group.Puerarin could improve the general health of the rats,decrease blood urea nitrogen,serum creatinine,and urinary albumin excretion rate of 24-hours;and increase the clearance rate of creatinine.The ICAM-1mRNA expressions in the kidney were significantly inhibited by puerarin treatment.Conclusion Puerarin has a function of renal protection.

Objective To investigate the variation law of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values in patients with cerebral infarction, and to explore the relationship between the changes and the prognosis of cerebral infarct patients. Methods Sixteen patients with cerebral infarction were recruited and divided into 2 groups:good recovery and poor rehabilitation. ADC and FA values were calculated in infarct areas and control areas which were the regions with symmetrical position and the same area as infarct areas. The difference of ADC and FA values in patients at acute and earlier chronic stage between the two areas were analyzed. Results ①At acute stage, ADC values in infarct areas were lower than those in control areas (P<0.05). At early chronic stage, there was no significant difference of ADC values between infarct areas and control areas (P>0.05), moreover ADC values were higher than that at acute phase (P<0.05). ②FA values in infarct areas were lower than those in control areas at both acute and early chronic stage (P<0.05). At early chronic stage, FA values were lower than those at acute stage (P<0.05). ③There was no significant difference of ADC and FA values at both acute and early chronic stage between good recovery group compared with poor rehabilitation group (P>0.05). Conclusion There are certainly rules in changes of ADC and FA values in patients with cerebral infarction at acute and earlier chronic stage.

ObjectiveTo investigate the postoperative 3D MRI appearances and their evolvement patterns of ACL grafts and bone tunnels at follow-up.Methods There were 26 double bundles ACL reconstructions and 16 single bundle ACL reconstructions,and a total of 56 follow-up 3D MR Imaging.MR images were reconstructed with MPR technique to evaluate grafts,bone tunnels,fixers and associated.complications.Proportions of grafts with hypointensity or hyperintensity and occurrence rates of marrow edema around bone tunnels were calculated respectively among groups of different periods after operation.ResultsThere were 24 grafts of hypointensity and 32 grafts of hyperintensity.Grafts of 2 cases were suspended with cross pins within femoral tunnels,graft of 1 case was suspended with an endobutton within the femoral tunnel,and grafts of other sites were fixed with interference screws.In the three periods as 3 months,6 to 9 months and over 12 months after cruciate ligament reconstruction,proportions of hypointensive grafts were 20/25,0/14 and 4/10 respectively,while proportions of hyperintensive grafts were 5/25,14/14 and 6/10 respectively,occurrence proportions of marrow edema around bone tunnels were 54/54,10/32 and 4/26 respectively.There was 1 tear graft,4 tibial tunnels placed anteriorly with ACL graft impingement on the intercondylar roof,3 femoral tunnels placed anteriorly,and 2 bone tunnels with mismatching interference screws.Conclusion3D MRI can accurately demonstrate the state of ACL grafts,bone tunnels,fixers and associated complications.Intensity of grafts presented a rise and reduce pattern after operation.

Objective To evaluate the apparent diffusion coefficient (ADC) of parenehyma and necrosis in distinguishing among metastatic lymph nodes, lymphoma and tuberculous lymph nodes. Methods Thirty-six patients with cervical lymph nodes metastasis from the head and neck squamous cell carcinomas,19 patients with lymphoma and 23 patients with lymph nodes tuberculosis underwent diffusion-weighted imaging. The ADC values were measured and compared in parenchyma and necrosis of 177 lymph nodes confirmed by histopathology (n = 114) and clinical follow-up (n = 63). The means between two groups were compared by t-test, and one-way analysis of variance (one-way ANOVA) was used to analyze the data among three or more groups. Results The mean ADC values of parenchyma in metastatic nodes, lymphoma and tuberculous nodes were (0.93±0.16) × 10-3mm2/s, (0.64±0.13) × 10-3mm2/s and (1.01±0.11) ×10 -3 mm2/s respectively (F = 82.928, P < 0.01) ; the ADC values of necrosis in metastatic and tuberculous nodes were (2.02 ± 0. 36) × 10-3 mm2/s and (1.25 ± 0.15) × 10-3 mm2/s respectively (t = 12.045, P <0.01). An ADC value of parenchyma lower than or equal to 0.77 × 10 -3mm2/s was used as the threshold for lymphoma, with a sensitivity 83% and specificity of 89%. An ADC value of necrotic area greater than or equal to 1.60 × 103mm2/s was used as the threshold for metastatic nodes, with a sensitivity of 88% and specificity of 100%. Conclusion The ADC value of lymph nodes, especially for their internal necrotic areas, can help judge the nature of the cervical lymph nodes.

Objective To investigate the clinical value of three dimensional dynamic contrast enhanced MRA(3D DCE MRA)on esophageal and gastric varices compared with endoscopy.Methods From April 2003 to June 2008,153 patients with portal hypertension who underwent both 3D DCE MRA and endoscopy were reviewed retrospectively.All the patients were divided into bleeding group and non-bleeding group according to the clinical symptoms.The location and degree of the esophagogastric varices on 3D DCE MRA were assessed with postprocessing images,including subtraction,MIP and thin-slab maximum intensity projection(thin-MIP),and were compared with the results of endoscopy.The maximum,minimum and mean diameters of esophagogastric varices inside and outside of the wall were measured on the reformed images.The correlation between the findings of 3D DCE MRA and endoscopy were analyzed with Spearman rank correlation coefficient test The rates of esophagogastric varices outside of the wall in bleeding and non-bleeding group were compared by means of Chi-square test Results In bleeding group,severe esophageal varices were documented in 59 patients,moderate in 6 patients,mild in 5 patients;in non-bleeding group,severe esophageal varices were documented in 32 patients,moderate in 4 patients,mild in 5 patients.Severe,moderate,and mild gastric varices were documented in 28,34 and 16 in bleeding group,while they were 7,12 and 9 in non-bleeding group.Esophageal and gastric varices can be wholly presented on MIP images after subtraction,while the esophagogastric varices inside and outside of the wall can be differentiated on thin-MIP images.The location and degree of esophagogastric varices on 3D DCE MRA were correlated with the findings of the endoscopy.The range of r was from 0.544 to 0.878(P＜0.01).In 91 patients with severe esophageal varices,27 patients presented outside esophageal varices in bleeding group(n=59)and 24 patients presented outside esophageal varices in non-bleeding group(n=32).There was a significant difference in ratio of outside esophageal varices between bleeding group and nonbleeding group(X~2=7.199,P＜0.01).In 35 patients with severe gastric varices,22 patients showed adventitial gastric varices in bleeding group(n=28)and 4 patients showed adventitial gastric varices in non-bleeding group(n=7).The ratio of adventitial gastric varices in bleeding group was not significantly different from that of non-bleeding group(P=0.340).Conclusions 3D DCE MRA can display and differentiate the esophagogastric varices both inside and outside of the wall by three dimensional reconstruction.The results of 3D DCE MRA and endoscopy have good correlation.It is of importance in evaluating the esophageal varices outside of the wall,because they may indicate decreased risk of haemorrhage in patients with severe degree of esophageal varices.

Objective The purpose of our study was to investigate three dimensional dynamic contrast enhanced MR angiography(3D DCE M RA) in the detection of portosystemic collateral circulation in the falciform ligament in patients with portal hypertension. Methods From April 2003 to July 2008, 53 portal hypertension patients with varices in the falciform ligament were evaluated with 3D DCE MRA.Two radiologists independently assessed the number, diameter, location and drainages of the portosystemic collateral circulation in the falciform ligament according to the information on the 3D DCE MRA.Results The veins in the falciform ligament were classified into the superior and inferior groups, and both groups arise from the left trunk of the portal vein.In our study, the number of varices detected on 3D DCE MRA images varied from 1 to 3, and the diameters of these vessels varied from 0.4 to 2.6 cm.The inferior group consisted of paraumbilical/umbilical veins (47 cases), which flowed toward umbilicus and then drained upwards (n = 16) including deep superior epigastric veins (n = 7), superficial superior epigastric veins (n = 9), downwards (n = 40) including deep inferior epigastric veins (n = 7), superficial inferior epigastric veins (n = 33), or upwards and downwards at the same time (n = 9).The superior group of vessels in the falciform ligament were directly anastomosed with the internal thoracic vessels (n = 6).Conclusion In patients with portal hypertension, 3D DCE MRA can optimally demonstrate the portosystemic collateral circulation in the falciform ligament, which includes the superior and inferior drainage groups.

Objective To discuss the value of MR T2 mapping in the research of the biomechanics and function of cartilage of knee joint.Methods Knees of 20 healthy adults before and after jogging and 19 osteoarthritis patients were examined with sagittal 8-echo SE sequence.The T2 value of cartilage was selected and calculated.The T2 values in the superficial and deep cartilage of femoral and tibial joint before and after jogging were compared,so did between the osteoarthritis patients and healthy adults.The source images were sent to the workstation to get T2 mappings.The T2 value of cartilage between before and after jogging was compared with paired-samples t test.The T2 value between superficial and deep cartilage before jogging was compared with independent-samples t test,so did between the osteoarthritis patients and healthy adults.Results The T2 values in the superficial and the deep tibial cartilage were(48.8±6.3)ms,(44.3±5.7)ms before jogging and(43.4±5.0)ms,(40.3±6.1)ms after jogging.The T2 values were significantly different between before and after jogging(t=6.004 and t=5.037,P＜0.05).There was a significant difference between superficial and deep tibial cartilage before jogging(t=3.148,P＜0.01).The T2 Values in the superficial and deep femoral cartilage were(52.1±5.7)ms,(47.7±5.3)ms before jogging and(47.2±4.5)ms,(43.6±4.1)ms after jogging.The T2 values were significantly different between before and after jogging(t=6.169 and t=5.957,P＜0.05).There was a significant difference between superficial and deep femoral cartilage before jogging(t=3.384,P＜0.01).The T2 mapping showed those changes.The mean T2 value in the tibial cartilage of osteoarthritis patients was(56.0±9.1)ms and was higher than that of healthy adults.There was a significent difference between osteoarthritis patients and healthy adults(t=-3.446,P＜0.01).Conclusion T2 mapping can be used in the research of biomechanics and function of cartilage and has a prelimilary value in the diagnosis of cartilage degeneration.