Objective To study the application of magnetic resonance T2 -mapping and diffusion weighted imaging(DWI)in diagnosis of early cartilage degeneration of the knee joint.Methods 56 patients with clinical intends to diagnosis of early osteoarthritis of the knee were set as observation group,another 56 healthy volunteers were selected as healthy control group.The subjects of the two groups were given knee MRI T2 mapping and DWI,the T2 acquisition value and ADC value of the two groups were analyzed and compared.Results In the observation group, the side of the femoral (37.18 ±4.09),lateral tibial (32.16 ±2.75)and hip (34.56 ±4.21)were significantly lower than those in the healthy control group[femoral side (49.87 ±5.02),tibial side (47.34 ±5.01),hip surface (51.23 ±5.19)](t =20.16,18.36,23.65,all P <0.05).Conclusion Magnetic resonance T2 -mapping and DWI imaging can be found in the early knee cartilage degeneration,can lead to the rise of T2 and ADC value,so there is no cartilage damage to the cartilage damage.

Objective To establish the normal parameters of psychometric measures such as the number connection tests A(NCT-A)and digit symbol tests(DST)in assessment of minimal hepatic en- cephalopathy(MHE).Methods One hundred and sixty healthy volunteers(aged 25 to 64 years;educa- tional level＞9 years)were divided into＜35 ys,35～44 ys,45～54 ys and 55～64 ys groups.All of the healthy volunteers were assessed with NCT-A and DST to establish the normal value of age-related parameters,which can be used for diagnosis of MHE in patients with liver cirrhosis.Two standard devi- ation of the normal mean was used as a diagnostic criterion for MHE.One hundred and six cirrhotic patients were assessed with these parameters.Results The parameters of NCT-A were(25.1?4.6) sec in＜35 ys group,(32.1?6.8) sec in 35～44 ys group,(38.6?7.1)sec in 45～54 ys group or (49.3?6.3)sec in 55～64 ys group.The scores of DST were 49.9?4.7 in＜35 ys group,44.6?4.8 in 35～44 ys group,38.5?5.0 in 45～54 ys group or 35.4?4.7 in 55～64 ys group.Thirty one out of 106 cirrhotic patients were diagnosed as MHE based on these parameters.Conclusion The NCT- A and DST are psychometric assessments for diagnosis of MHE.Age-based normal paramerters of NCT- A and DST are needed to be established.

OBJECTIVETo compare the accuracy of CT and MR including diffusion-weighted imaging(DWI) in preoperative diagnosis and T staging of gastric cancer.

METHODSForty-one patients with gastric cancers proved by gastroscopy biopsy from November 2011 to August 2012 were prospectively enrolled. They underwent contrast enhanced CT and MR imaging (including DWI, T2 weighted and dynamic enhanced imaging) preoperatively. Two radiologists interpreted CT and MR images for detecting and staging each patient independently. With the reference of post-operative histopathological findings, T staging accuracy of CT and MR imaging was calculated and compared. Inter-observer agreement was also evaluated.

RESULTSOverall T staging accuracy in MR including DWI was significantly higher than that in CT imaging(87.8% vs. 65.9%, P=0.004). MR had a better inter-observer agreement than CT(Kappa=0.813, 0.603, respectively).

CONCLUSIONMR including DWI can improve preoperative T staging accuracy of gastric cancer significantly, which deserves recommendation for clinical application.

Biopsy ; Contrast Media ; Diffusion Magnetic Resonance Imaging ; Gastroscopy ; Humans ; Magnetic Resonance Imaging ; Neoplasm Staging ; Stomach Neoplasms ; pathology

OBJECTIVETo explore the preoperative diagnostic value of MR diffusion weighted imaging (DWI) for metastatic lymph nodes in patients with gastric cancer.

METHODSBetween December 2011 and December 2012, 52 gastric cancer patients(34 men, 18 women) underwent preoperative MR DWI. The apparent diffusion coefficient(ADC) and short diameter of lymph nodes were measured and compared with the postoperative histopathological findings. Diagnostic value of ADC and short diameter for metastatic lymph nodes in patients with gastric cancer was investigated by receiver characteristic curve(ROC) analysis.

RESULTSA total of 180 metastatic and 57 non-metastatic lymph nodes were detected as hyperintense on DWI obtained from 52 patients. The ADC of metastatic lymph nodes [(1.059±0.196)×10(-3) mm(2)/s] was significantly lower than that of non-metastatic nodes [(1.402±0.285)×10(-3) mm(2)/s, P<0.001]. With ADC threshold of 1.189×10(-3) mm(2)/s, the sensitivity, specificity and area under the curve(AUC) were 78.9%, 72.8% and 0.840, respectively. The overall diagnostic accuracy of preoperative N staging of ADC was 75%(39/52). The short diameter of metastatic lymph nodes [(8.08±3.99) mm] was significantly longer than that of non-metastatic lymph nodes [(6.75±2.70) mm, P=0.005]. With short diameter threshold of 5.05 mm, the sensitivity, specificity and AUC were 88.3%, 29.8% and 0.602, respectively. The overall diagnostic accuracy of short diameter in preoperative N staging was 67.3%(35/52).

CONCLUSIONSMR DWI is a useful technique in diagnosing metastatic lymph nodes in patients with gastric cancer. ADC value and short diameter can be used as diagnostic criterion for the diagnosis of preoperative N staging.

Diffusion Magnetic Resonance Imaging ; Female ; Humans ; Lymphatic Metastasis ; Magnetic Resonance Imaging ; Male ; ROC Curve ; Stomach Neoplasms ; pathology

Objective To explore the clinical characteristics and etiology of intractable postpartum hemorrhage requiring hysterectomy. Methods We retrospectively collected 152 patients with intractable postpartum hemorrhage between January 2005 and March 2016 in Department of Obstetrics and Gynecology of Peking University First Hospital. Analysis was conducted to identify the general status, etiology, high risk factors, complications and outcome of patients with or without hysterectomy (hysterectomy group and conservative group). T-test, Rank sum test, and Logistic regression analysis were applied in the statistical analysis. Results (1) Totally 152 patients were identified, accounting for 0.3% of total deliveries during the study period (152/48 694). Among them, 111 cases (73.0%) received routine prenatal care in our hospital; and 41 cases (27.0%) were transferred from other hospitals for high-risk pregnancy. The median blood loss within 24 h after delivery was 1 807(1 027-10 000) ml and 6 (2-42) U of red blood cells was transfused. Totally, uterus was removed in 29 cases (19.1%), with a hysterectomy rate of 0.060% (29/48 694) among all deliveries. (2) The proportion of women with previous cesarean sections [62.1%(18/29) vs 9.8%(12/123), χ2=40.541], the total amount of blood loss within 24 h postpartum [5 145(2 061-10 000) vs 1 586 (1 027-7 350) ml, Z= － 7.671] and of transfused red blood cells [24(6-42) vs 6(2-40) U, Z= － 7.485] were all significantly higher in the hysterectomy group than those of the conservative group. (3) The main causes for intractable postpartum hemorrhage were uterine atony (66/152, 43.4%), placental factors (58/152, 38.2%), soft birth canal injury (21/152, 13.8%) and coagulation dysfunction (7/152, 4.6%). The proportions of placenta factors and coagulation dysfunction in hysterectomy group were higher than those of the conservative group [69.0%(20/29) vs 30.9%(38/123), OR(95% CI): 4.971(2.071-11.912); 20.7%(6/29) vs 0.8%(1/123), OR (95% CI): 31.826(3.654-276.132)], while the proportion of uterine atony was lower [3.4%(1/29) and 52.8%(65/123), OR(95%CI):0.032(0.001-0.241)] (all P<0.01). No statistical difference was shown in the proportion of soft birth canal injury between the two groups. (4) Among the 152 cases, 17.8%(27/152) were admitted into the intensive care unit (ICU) and 15.8%(24/152) experienced severe complications. More postpartum women developed severe complications or being transferred to the ICU in the hysterectomy group than in the conservative group [65.5%(19/29) vs 4.1% (5/123), χ2=72.423; 72.4%(21/29) vs 4.9%(6/123), χ2=73.273; all P<0.001]. Conclusions For women with intractable postpartum hemorrhage cases requiring hysterectomy, previous cesarean section complicating with placenta accreta, is the major reason, while those complicated with coagulation dysfunction carries the highest risk. Meanwhile, those caused by uterine rupture should not be ignored. Although uterine atony remains the leading cause, uterus may be preserved through conservative surgery in most cases in hospitals with adequate medical resources and techniques.