Purpose Placenta accreta is a rare but severe pregnancy complications, and imaging diagnosis is always difficult. This paper aims to analyze the MRI manifestations of placenta accreta, and explore its misdiagnosis reasons. Materials and Methods A retrospective study was carried out on the findings and classification of MRI plain scan and diffusion weighted imaging (DWI) scan of 18 patients with placenta accreta confirmed surgically and pathologically. Results The prenatal MRI scan reported 15 patients of placenta accreta correctly (83.33%), and missed 3 (16.67%) among which 2 were with placenta accreta and the other 1 with placenta increta. The MRI of placenta accreta presented rather thin muscular layer, discontinuous junctional zone, and some unclear boundary of placenta and uterine wall; the signal of the placenta was heterogeneous, and we could see enlarged vessels of extremely low signal on T2 HASTE and high signal on TruFISP sequences, and low signal of thick intraplacental band; moreover, hematoma with high intensity on T1WI and low intensity on T2WI could be seen. DWI demonstrated uneven intensity and dark thicker intraplacenta bands in 2 cases. Conclusion As an important clinical auxiliary tool in diagnosing placenta increta, MRI has high accuracy in the diagnosis of placenta increta and placenta percreta; however, it has rather low accuracy in placenta accreta.

Objective To investigate the pathologic bases of MRI manifestations of rabbit VX2 hepatic carcinoma.Methods 32 foci of hepatic carcinoma models in 20 rabbits VX2 were set up by implantation.Plain MR examinations in all rabbits and contrast-enhanced MR scan in 10 rabbits(15 foci) were performed 2~4 weeks after implantation.The largest transverse section specimens of all the tumors were obtained for imaging-pathology comparative study after MR scan.Results All the 32 tumors were detectable on both T1WI and T2WI.The size of the tumors ranged from 0.5 to 3.5 cm in diameter.6 foci showed homogeneous slight hyperintense on T2WI,the other 26 showed characteristic intratumoral signal intensity on T2WI,including "nodule in nodule"sign in 5 foci,"target"sign in 7 foci,and "dot and color"sign in 14 foci.The characteristic intratumoral signal showed on T2WI were pathologically testified as necrotic tumor tissue of different structures.All the 15 tumors with contrast-enhanced scan appeared annular enhancement in different degrees,slight enhancement in 6,medium enhancement in 7 and obvious enhancement in 2.The sinusoidlike vascular space between tumor cells were significantly dilated in the obvious enhancement cases,and there were many spots of necrosis in the slight enhancement tumors under microscope.Conclusion The tectology of intratumoral necrosis can be evaluated by T2WI.Enhanced degree after administration of contrast agent in the hepatic cancer in rabbit model is associated with dilating degrees of sinusoidlike vascular space and number of dotted necrosis of tumors.

Objective To evaluate the enhancing effect of MRI with Gd DTPA F(ab)′ 2 in nude mice models with LS 174T tumor, and to investigate the influence of Gd labeling on the immunocompetence of the fragments (ab)′2 of CL 3. Methods (1)Antibodies and tumor models preparation: Monoclonal antibodies (McAb) fragment F(ab)′ 2 against LS 174T colonic adenocarcinoma cell were prepared with hybridoma cell CL 3. Twenty BALB/C nude mice were used as tumor models by subcutaneous injection of LS 174T cells. (2)Gd 3+ Labelling: DTPA anhydride and F(ab)′ 2 fragments were conjugated. Two groups were classified: group A, with C/P=2∶1; group B, with C/P=5∶1. Then, Gd was added into DTPA F(ab)′ 2 solution. Gd DTPA F(ab)′ 2 was formed. Free Gd 3+ and DTPA were removed by dialysis. Purified Gd DTPA F(ab)′ 2 was available. (3) MR scanning techniques: MRI was performed with a GE Signa Horizon LX MR scanner. The nude mice were immobilized and divided into three groups: routine plain scan group, enhanced scan group A(C/P=2∶1)and group B(C/P=5∶1). Results When pH=8.0 ,[F(ab)′ 2]=4.6 mg/ml, and C/P=2∶1 or C/P=5∶1, immuno conjugated rates of group A and B were 74% and 62%, respectively. Immunocompetence of fragment F(ab)′ 2 reduced approximately 12% when C/P increased from 2∶1 to 5∶1.The enhancing effects of two groups of nude mice were both poor, and that of group B(C/P=5∶1) was better than that of group A(C/P=2∶1). Conclusion While C/P increasing, immunocompetence of fragment F(ab)′ 2 reduced, and the enhancing effects of group B was better than group A. The enhancing effect of Gd DTPA F(ab)′ 2 was tumor specific.

Objective To evaluate the possibility and scan the protocol of diffusion tensor imaging(DTI) in rabbit VX2 liver tumor models.Methods MRI and DTI images were obtained from 16 rabbit VX2 liver tumor models and 4 rabbit control liver models.Average diffusion coefficient(ADC),fractional anisotropy(FA) of tumors and control livers were estimated and compared with the changing rules(b value=100,600,1000 mm2/s).Results ADC of tumors had a descending trend and FA of tumors had an increasing trend compared with control livers.The fluctuations of ADC and FA of tumors had a descending trend(P

Objective To evaluate the curative effect and optimal indications of reformed percutaneous lumbar diskectomy (RPLD) for the treatment of lumbar disc herniation.Methods One handred and thirty-three patients with lumbar disc herniation were treated by RPLD, of them, 20 cases were lumbar disc extrusion and 113 cases were lumbar disc protrusion. After the procedure, 85 patients underwent flush of intervertebral space with antibiotic saline and 48 patients underwent 10 ml(40?g/ml) medical ozone-injection inside the disc to prevent infection. All patients were followed up over the course of 3 months. The therapeutic effect was evaluated according to the MacNab criteria. Results All 133 cases underwent RPLD were successful. The total efficacy was 81.9%, There were no serious complications after operations. Conclusion RPLD is an effective method in the treatment of lumbar disc herniation. Both intradiscal ozone-injection or intradiscal antibiotic saline flush after RPLD can reduce the opportunity of infection.

Objective To analyze the correlation between quantitative evaluation of high-resolution CT (HRCT) and pulmonary function tests (PFT) in chronic obstructive pulmonary disease (COPD), and evaluate the characteristics of PFT in different CT phenotypes of COPD. Methods 65 patients with COPD underwent CT chest scan and PFT. The dimensions of subsubsegmental apical bronchi of right upper lobes were measured , which included the following parameters:airway wall thickness (T), total airway diameter (D), and pulmonary artery (PA), ratio of airway wall thickness and pulmonary artery (T/PA), thickness diameter ratio (TDR), percentage of wall area (WA%) and percentage of airway luminal area (Ai%). The percentage of total lung area occupied by low attenuation area (LAA%) was measured by lung density software. The relationship between the measurements and PFT parameters were analyzed. Patients were classified into three phenotypes based on the presence of emphysema or bronchial wall thickening evaluated by HRCT. Phenotype A: without or with little emphysema (LAA% < 25%), with or without bronchial wall thickening; Phenotype E: emphysema without bronchial wall thickening (LAA%≥25%, T/PA < 30%); Phenotype M: emphysema with bronchial wall thickening (LAA%≥25%, T/PA≥30%). The characteristics of different CT phenotypes were analyzed. Results LAA% had a good correlation with PFT parameters. PA, T/PA, WA% and Ai% also had correlation with PFT parameters. There was 53 patients of Phenotype A, 12 patients of Phenotype M. PA, T/PA, LAA%and PFT were different in two groups. Conclusions LAA%and airway quantitative measurements in HRCT have certain correlation with PFT parameters. Patients with different CT phenotypes differs in PFT parameters , which can provide reference for clinical diagnosis and treatment.

Purpose To investigate the value of 3.0T MR T1ρquantitative analysis in early detection of disc degeneration. Materials and Methods Conventional T2WI and T1ρwere collected in 35 healthy volunteers (male 16, female 19) on 3.0T MRI, and the classification of disc nucleus was performed by Pfirrmann classification. T1ρvalue of nucleus pulposus was measured and analyzed for the relationship among Pfirrmann classification, segmental and gender. Results There was a significant negative correlation between T1ρvalue and Pfirrmann grade (r=-0.542, P<0.001). T1ρvalue in L5/S1 segment (94.80±26.60) ms was significantly lower than that in L2/L3 (117.18±25.64) ms and L3/L4 (115.52±28.53) ms (P<0.01), and there was no significant difference among other segments (P>0.05);there was no gender differences among the T1ρvalue of each segment (t=0.006, 0.042, 0.797, 1.022, 0.038, P>0.05). Conclusion T1ρ value is closely related to the degree of disc degeneration, and T1ρimaging can be used as an objective, sensitive and effective tool for early detection of disc degeneration.

ObjectiveTo evaluate the characteristics of MRI of common hepatic lesions by using measurement of T1,T2 and ADC on the MRI and DWI. MethodsMRI and DWI were obtained in 100 patients with common hepatic lesions, and T1,T2,ADCs and the ratios of the ADC of lesion/liver were estimated. (Results)Average T1,T2 and ADCs of hepatic lesions were as follows: hepatocellular carcinoma, (843.92167.75) ms , (73.9014.21) ms and(0.990.26)10~(-3)mm~2/s respectively; hepatic (metastasis), (946.89186.13) ms, (76.3919.76) ms and(1.170.32)10~(-3)mm~2/s (respectively); hepatic cavernous hemangioma, (1102.33213.12)ms, (142.3228.51) ms and (1.810.42)10~(-3)mm~2/s respectively; hepatic cyst, (1516.32617.84)ms ,(247.33112.52)ms and (3.110.38)10~(-3)mm~2/s respectively. The ratio of the ADC of lesion/liver:(hepatocellular) carcinoma was 0.890.17, and significantly lower than the ratio of hepatic metastases((1.27)0.21, P

Objective To compare the consistency and correlation of multiple breath-hold (BH) with respiratory-triggered (RT) 1H-MRS for quantification of hepatic lipid content. Methods Sixty subjects were underwent RT 1H-MRS of the liver (Couinaud segment VII) and BH 1H-MRS at 1.5 Tesla Magnetic Resonace Imaging (MRI). The peak areas of water and methylene obtained on RT and BH 1H-MRS were recorded respectively and the liver fat fraction was calculated. Pearson correlation coefficient , Bland-Altman 95% limit of agreement, and concordance correlation coefficient were calculated. Results Mean liver fat fraction measured in RT and BH 1H-MRS were (8.6 ± 8.7)% and (9.4 ± 9.3)% respectively. There was a strong correlation between RT and BH 1H-MRS(r = 0.973, P < 0.000 1, concordance correlation coefficient = 0.95). With the Bland-Altman method, 91.7% data points were within the 95% limits of agreement. Conclusion RT and BH 1H-MRS are alternative tools for intrahepatic lipid quantification. These two methods have a strong correlation and perfect consistency.

Objective To investigate the ability of T2 mapping in early detection of the change of cartilage collagen by quantitative analysis.Methods 20 porcine patellae were randomly assigned into 4 groups,3 treated groups and 1 control group.The samples of 3 treated groups were respectively immersed in PBS with 100 mg/100 mL,1 50 mg/100 mL and 200 mg/100 mL typeⅡ collagenase for 4 h,whereas control group samples in PBS for 4 h.T2 relaxation times of superficial,deep and full layers of cartilage and mean densi-ty after Van Gieson stain were measured.The correlation of T2 relaxation times and mean density were statistically analyzed.Results Gross pathology showed all articular cartilages maintained intact after treatment.T2 relaxation times of superficial and full layers and mean density increased significantly in any treated group in comparison with control group(P <0.05).Significant differences in T2 relaxation times of superficial layers and mean density were found between any two treated groups,whereas no difference of T2 re-laxation time of full layers was found between 100 mg/100 mL and 1 50 mg/100 mL treated groups(P >0.05).Pearson correlation analysis showed a close correlation(r=-0.837)between T2 relaxation times of full layers and mean density.Conclusion T2 map-ping can adequately detect the change of cartilage collagen in the early stage of osteoarthritis,and shows a good clinical application prospect.