Objective To study the feasibility of cerebral perfusion weighted imaging(PWI)using superparamagnetic iron oxide particles(SPIO)Resovist in normal rabbits,and investigate the methodology and the proper contrast agent dose of SPIO in PWI.Methods All 30 rabbits were randomly divide into 5 groups(n=6 for each),group A,B,C,D were divided according to the different dose of Resovist(4,8,16 and 32 μmol Fe/kg)and group E was operated as control study with 0.2 mmol/kg Gd-DTPA.The dynamic MR perfusion imaging series were acquired in each group.The signal intensity time curves were analyzed in gray matter and white matter,and the parameters(rCBV,SRRmax,QrCBV,QSRR max)were calculated and compared in all groups and correlated with control one.Results a bolus injection was succeed for all studies.and a dose-dependent strong reduction in signal intensity of gray and white matter in all groups was demonstrated.The rCBV values of gray and white matter for group A,B,C,D and E were(50.48±3.84),(25.57±2.10);(94.69±2.60),(45.33±3.14);(141.13±6.26),(67.67±4.65);(243.75±5.90),(162.06±5.14);and(84.60±3.60),(41.36±2.18)ml/100 g,respectively.The SRRmax values of gray and white matter for group A,B,C,D and E were(13.70±1.50)%,(7.38±0.41)%;(31.01±4.06)%,(16.49±2.35)%;(43.81±3.42)%,(21.64±4.14)%;(64.49±5.35)%,(43.61±5.78)%;and(27.78±2.98)%,(14.42±2.25)%;respectively.The QrCBV values for group A,B,C,D and E were 1.98±0.07,2.09±0.11,2.09±0.07,1.50±0.01,and 2.05±0.03,respectively,and the QSRR max values for group A,B,C,D and E were 1.85±0.11,1.88±0.06,2.06±0.25,1.49±0.09,and 1.94±0.12,respectively.All above values among group were significantly different(P＜0.01).For the QrCBV and QSRR max values between group,there were no significant difference between group A and B,B and C,A and C;while the values of group A was significantly larger than those of group D(P＜0.01).Condusion Resovist(SPIO)can be used in the study of MR perfusion weighted imaging in the brain,and the proper contrast agent dose is 4-16 μmol Fe/kg.

Objective To analyze the characteristic findings of chest high-resolution CT (HRCT) in the patients with syetemic lupus erythematosus (SLE).Methods A retrospective analysis of HRCT manifestations was performed in 17 patients with clinically proven SLE.Results The HRCT finding included thickened interiobular septa(n=9), “irregular interface” sign(n=7), subpleural bands(n=7), increase lung attenuation(n=7), bronchiectasis(n=3), “honeycomb” sign(n=4), pulmonary emphysema(n=6), SLE pneumonia(n=4), nodular parenchymal opacities(n=4), patchy airspace consolidation(n=4), pleuritis(n=13), pericarditis(n=3) and mediastinal or axillary lymphadenopathy(n=8).Conclusion The correct identifying of the HRCT manifestations plays an important role in the early diagnosis and treament of pulmonary involvement due to SLE.

Objective To analyze CT findings of solitary fibrous tumors of the pleura (SFTP) for differentiating benign and malignant lesions.Methods CT findings of 20 benign and 11 malignant SFTPs proved by pathology were retrospectively reviewed. The size,margin,internal structures,blood supplies,invasion to adjacent structures or metastasis and pleural effusion were analyzed and compared between malignant and benign groups.Results The mean diameter of malignant lesions( median diameter:13.5 cm) was larger than that of the benign ( median diameter:7.6 cm,F =6.411,P =0.017 ).Malignant lesions tended to be more heterogeneous (9/11,P =0.002),more invasive to adjacent structures ( 6/11,P =0.001 ) than benign lesions ( 4/20,0/20 ).Serpiginous vessels ( 10/11,P =0.008 ) and pleural effusion (6/11,P =0.038 )were more common in malignant lesions than those in benign lesions (8/20,3/20).Calcification could be found in both benign (2/20) and malignant lesions ( 2/11,P =0.6 ).Furthermore,3D CT angiography could show blood supplies into tumor in 12 lesions (4 benign and 8 malignant SFTPs).Conclusion CT and 3D CTA are helpful in differentiating benign from malignant SFTPs and evaluating the excision of SFTPs.

Objective To evaluate the clinical application value of susceptibility weighted imaging (SWI) in neonatal hy-poxic ischemic encephalopathy (HIE). Methods Thirty-six neonates with HIE were collected and scanned by GE 3.0 T supercon-ducting MR scanner. Routine axial T1WI, T2WI, FLAIR scan and axial SWI scan were conducted. SWI sequence was compared with conventional head MRI sequences in detection rate of distribution and quantity of intracranial hemorrhage. Meanwhile, the display condition of the dilated cerebral deep veins and cortical veins was observed on SWI image and the performance of HIE in different clinical classification on SWI was compared. Results A total of 97 intracranial hemorrhages were detected by SWI in 27 cases. Only 41, 27 and 51 hemorrhages were found by TIWI, T2WI and FLAIR sequences, respectively. SWI were significantly superior to T1WI, T2WI and FLAIR in displaying the size, scope and boundary definition of hemorrhage. A total of 50 dilated ce-rebral deep veins and cortical veins were detected by SWI in 22 cases which were not found by conventional head sequences. The detection rates of intracranial hemorrhage and intracranial hemorrhage in addition of dilated cerebral veins on SWI sequence were the lowest in mild HIE group, and highest in severe group. There was significant difference among the mild, medium and severe groups (P<0.05). Conclusions SWI sequence has higher sensitivity than conventional MRI sequence in detecting intracranial hemorrhage and dilated vein in HIE, and is useful for early diagnosis of HIE.

Objective To evaluate blood oxygen level-dependent (BOLD) MRI on assessing renal damage after injection of iodine contrast medium with a 3.0 T system. Methods Routine MRI examination,including T1WI and T2WI, and BOLD MRI were performed in 29 SD rats with a 3.0 T system before the injection of iodine contrast agent and 20 min, 24 h, 48 h, 72 h after the injection, respectively. T2 * and R2 * ( = 1/T2 * ) measurements were obtained in the cortex, inner and outer medulla of kidney,respectively. The results obtained before contrast agent administration were considered as the self-controls.AVONA test were used for the comparison of R2 * values in different parts of both kidneys before contrast agent administration. Two-sample t test was used to compare R2 * values before and at each time point after contrast agent administration, and R2 * values in different parts of the kidneys. Results Before contrast agentadministration, R2 * values in outer medulla in both sides of kidney [R2 *left oM = (31.76 ± 2.73 ) / s,R2 * right OM = (32.77±3.07) /s] were higher than those in cortex [R2 * left c=(30.20±3.48) /s,R2 * right c = (28.84 ±3.11 )/s] and in inner medulla [ R2 * letf IM = (29.54 ± 2.42) /s, R2 * right IM =(28.37±2.80) /s ] ( F = 3.357 and 14.961, P＜ 0.05 ). There was no statistical significance in R2 *values in the three parts between left and right kidney, including cortex, outer and inner medulla (P＞0.05). After contrast agent administration, R2* values in outer medulla changed obviously, which reached to the peak values at 20 minutes after contrast agent administration [R2* left OM = ( 43.57 ± 3.84 )/s,R2*right OM= (44.58±3.13) /s] and dropped from 24 hours [R2*left OM = (42.07 ±4.82) /s,R2* right OM = (42.89±3.40) /s]. R2* values in inner medulla and cortex only presented slight changes.Conclusion R2* values reflected the changes of oxygen content in renal cortex and medulla quantitatively,which helped for detecting medullar ischemia and hypoxia. BOLD MR imaging could offer a feasible method for evaluating oxygen metabolism and renal injury in cortex and medulla.

Objective To observe the multi-slice spiral CT manifestations of cavernous transformation of the portal vein (CTPV) secondary to tumor emboli from hepatocellular carcinoma (HCC). Methods MSCT manifestations of 31 patients of HCC with tumor emboli-induced CTPV proved by operation and pathology were collected and the data were retrospectively analyzed. Results Tumor embolus was detected in both the trunk, left and right branches of PV in 23 patients, accompanied with superior mesenteric vein and/or splenic vein and inferior vena cava's tumor embolus in 4 and infiltration of gallbladder in 1 of 23 patients, as well as in the trunk and left branch in 1, and in the trunk and right branch of PV in 5 patients, accompanied with right hepatic vein and/or inferior vena cava's tumor embolus in 2 and in the portal trunk and superior mesenteric vein in 1, only in the right branch in 1 patient, respectively. Tumor emboli were isodense in plain CT scan, but enhanced with obvious degrees in arterial phase and filling defects in portal venous phase. There were collateral vessels around portal vein. Lateral branches around hilar bile duct, the open of venous plexus around fossa of gallbladder, lateral veins around gastric fundus and lesser curvature, lateral veins of lower part of esophagus and expansion of splenic vein were found in 31 (100%), 19 (61.29%), 21 (67.74%), 7 (22.58%) and 15 patients (48.38%), respectively. Conclusion Tumor emboli-induced CTPV from HCC has specific MSCT findings being helpful to the diagnosis.

Objective To observe the multi-detector spiral CT manifestations of primary gastric lymphoma. Methods Multi-detector spiral CT findings of 21 patients with pathologically confirmed primary gastric lymphoma were retrospectively analyzed, the lesions' site, extent, thickness of gastric wall, the enhancement pattern, the situation of gastral cavity and gastric mucosa, and the encroachment of perigastric lymph nodes and other organs were observed. Results Tumors in all 21 patients were non-Hodgkin lymphoma. Multiple lesions were found in 19 patients, while single lesion was detected in 2 patients. CT demonstrated irregular thickening of the gastric wall (8-62 mm) in all 21 patients, including diffuse thickening (n=10), segmental thickening (n=9) and local thickening (n=2). Homogeneous enhancements were found in 19 patients, and lamellar inhomogeneous necrosis were found in 2 patients. Intact mucosal lines were found in 12, and destructed mucosal line in 9 patients, while obscure serous membranes were found in 2, and distinct serous membrane in 19 patients. The stomach showed distensible without significant narrow in 12 patients. The enlargement of perigastric lymph nodes were found in 6 patients. No hepatic encroachment was found. Conclusion Multi-detector spiral CT manifestations of primary gastric lymphoma are relatively specific, and multi-detector spiral CT shows high value for the diagnosis of the disease.

Objective The CT features of hepatic abscess (HA) were studied to differentiate form hepatocellular carcinoma(HCC).Methods The CT and operative-pathological findings of 78 cases with HA were analyied and compared with the CT appearances of a series proven cases of HCC.Results None of 25 cases had the so-called typical findings such as the marginal"double-target sign"and the even liquidizing necrotic area and containing gas zone within the lesion,53 cases had the central even liquidizing necrotic area,the marginal "Double-target sign",and containing gas zone within the lesion.Most of a typical hepatic abscess were early HA,and the precontrast CT showed nonspecific features.There were characteristic features on contrast CT.They were peripheral multicyst sign,sharp-edged sign spider-like sign,continued enhancement sign.Conclusion The CT features of HA are very valuable for the diagnosis of HA and the differential diagnosis from HCC.

Objective To investigate the feasibility of diffusion-weighted(DWI) MRI on basis of the intravoxel incoherent motion (IVIM) in nasopharyngeal carcinoma (NPC),and the diagnostic value of pure molecular diffusion coefficient (D),perfusion-related diffusion coefficient (D *) and perfusion fraction (f) in first onset NPC.Methods From December 2011 to January 2013,40 consecutive patients (26 men,14 women; median age,52 years) with suspected NPC were examined on a 3.0 T MR scanner.DW imaging was performed by using a single-shot echo-planar sequence with 13 b-values (0,10,20,30,50,80,100,150,200,300,400,600,800 s/mm2).MR imaging was compared with endoscopy and biopsy for the detection of NPC.Mean interval time between MR imaging examination and subsequent nasopharyngeal biopsy was 3 days (range,0-11 days).The subjects were divided into 2 groups according to the pathological results,group A was subjects with NPC (17 men,9 women; median age,35) and group B was ones with nasopharyngeal chronic hyperplastic inflammation(NPH) (9 men,5 women; median age,35).The D,D * and f were measured and compared in patients with first onset NPC and nasopharyngeal hyperplasia (Mann-Whitney test).Results IVIM DWI was successful in 24/26 with NPC and 12/14 with NPH.D value was significantly lower in A group compared with B group [mean,(0.70 ± 0.13) ×10-3 mm2/s vs (0.78 ± 0.05) × 10-3 mm2/s ; U =2.05,P ＜ 0.05],as was f value [mean,(16.25 ±1.46) ％ vs (26.20 ± 3.90) ％ ; U =11.16,P ＜ 0.01].However,D* value was significantly higher in Agroupas compared with B group[mean,(161.8 ±23.56) × 10-3 mm2/s vs (55.28 ± 17.05) × 10-3 mm2/s; U =13.90,P ＜0.01].Conclusions IVIM DWI is a feasible technique for investigating first onset NPC and D value has a certain value in differentiating NPC and NPH.D* value has an important potential value in distinguishing benign and malignant NPC.

Objective To explore the reproducibility of normal hepatic MRS at 3.0T. Methods The hepatic proton MRS was performed with GE Signa Excite HD 3.0T system and eight-channel torso phased-array coils using PRESS sequence. Thirty-one healthy individuals were enrolled in this study. Liver spectra were collected with TR of 1500 ms, TE of 30 ms, ROI of 2 cm×2 cm×2 cm, NSA of 64 times. The outcomes were statistically analyzed with Wilcoxon signed ranks test and Spearman correlation test.Results There was no significant difference of signal to noise ratio (Z=-0.535,P=0.593), baseline stability (Z=-0.333, P=0.739), linewidth of automatic shimming (Z=-0.305, P=0.761), water suppression (Z=-1.232, P=0.218), height of lipid peak (Z=-0.558,P=0.557), area under the lipid peak (Z=-1.195,P=0.232), height of water peak (Z=-0.647,P=0.518) and area under the warter peak (Z=-0.118, P=0.906) between first examination and second examination. Correlation coefficient of the former and the later measurements of lipid area and water area were 0.784 (P<0.001) and 0.799 (P<0.001), respectively.Conclusion The reproducibility is good for in vivo liver proton MRS at 3.0T.