Objective To explore the diagnostic value of MR diffusion weighted imaging (DWI) in the differential diagnosis between encephalitis and acute cerebral infarction.Methods The MR DWI appearances of 23 cases of encephalitis including 14 cases with viral encephalitis, 9 cases with demyelinative encephalitis and 30 cases with acute cerebral infarction were retrospectively analyzed.Results The 30 cases of acute cerebral infarction appeared bright signal in DWI with a ADC values of (0.46?0.13)?10 -3mm2/s. 7 cases with viral encephalitis and 9 cases with demyelinative encephalitis appeared slightly high or high signal intensity in DWI with a ADC values of (0. 98?0.18)?10 -3mm2/s and(0. 89?0.07)?10 -3mm2/s respectively. The ADC values of viral encephalitis and demyelinative encephalitis were higher comparing to acute cerebral infarction(?0.05). However, the ADC values showed higher or lower in different areas in 4 cases, and lower ADC values appearing in 3 cases with viral encephalitis comparing normal parenchyma.Conclusion MR DWI is useful in the differential diagnosis between encephalitis and acute cerebral infarction.

Objective To elucidate the spectrum of lipid peaks in 1H-MRS of skeletal muscle and it's interpretation,to investigate the utility of 1H-MRS in evaluating intramyecellular lipid (IMCL).Methods 1H-MRS was acquired in vivo on tibialis anterior muscle (TA) and soleus muscle (S) on 5 healthy volunteers.The spectrum of the lipid peak between 0.80 and 1.80 ppm was observed with different angle between the long axis of the calf and B0.Ex vivo phantom was an cluster of capillary tubers filled with soybean oil and fat emulsion,simulating the extramyecellular lipid (EMCL) and IMCL,respectively.The spectra of the lipid peaks were compared using different angles between the phantom and Bo field.Results The lipid spectrum split to 3 to 4 peaks between 0.80 and 1.80 ppm on calf muscles,with 0.20 to 0.30 ppm interval between each neighbouring peak.The methylene peak of EMCL shifted to the right when the angle between long axis of the calf and B0 increased.The phantom could simulate the spectrum of 1H-MRS of the muscle,presenting two peaks with 0.20 to 0.30 ppm chemical shift difference between 0.80 and 1.80 ppm.They are methyl triglyceride and methylene,representing IMCL and EMCL,respectively.The peak splitting could be attributed to the high ordered muscle fibers and their chemical shift difference between inta-and extra-cellular distribution.The interval of IMCL and EMCL peaks attenuated when the angle between the muscle fiber and B0 increased from 0 to the magic angle(54.7°).Conclusion On 1H- MRS spectrum,the peak of the EMCL and IMCL splits.This indicated that 1H-MRS is an applicable method to detect IMCL noninvasively.TA is an optimizing muscle for 1H-MRS study.

Objective To investigate the application of 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging. Methods Eight volunteers and a porcine fibula in vitro with intact muscle were involved in this study. Among the volunteers, one was suspected with meniscus tear, the others were asypmtomatic. MR imaging of 3D ultrashort TE double echo pulse sequence were performed on the tibial diaphysis, knee joint, ankle and wrist of each volunteer and the porcine fibula in vitro. Using the first echo images subtract with the second echo images, we observed the subtracted images from the primary double echo images and MPR images respectively. We then compared the difference of SNR. Four different echo times of the first echo (TE1) in the images were set as 0. 08 ms, 0. 16 ms, 0. 24 ms, 0. 35 ms. The quality of the subtracted images from the primary double echo images of the four different TE1 was compared.The MIP images from the primary double echo images with TE1 of 0. 08ms were performed to display the 3D structure of the ankle tendons. The data were analysed with One-Way ANOVA and Paired-Samples t test statistically. Results The 3D images of the tendons were displayed through MIP of the subtracted images from the primary double echo images. The cortical bones, periosteums, tendons and menisci of the 8 volunteers appeared as high signal intensity in UTE pulse sequence. The SNR of the subtracted images from MPR images (SNR, 3.76 ± 0. 88) was significantly higher than those from the primary double echo images(SNR,2. 82±0. 75) (t = - 4. 851, P < 0. 01). There were significant differences among the subtracted images from each of the four different TE1. The highest quality were obtained from the TE1 of 0.08ms. The CNR were as follows: CNR<,0.08ms>1.74±0. 54, CNR<,0.16ms> 1.35 + 0. 60, CNR0.24ms>1.20±0. 48,CNR<0.35ms> 0.89±0. 24 (F = 3. 681, P < 0. 05). The artifacts appeared markedly with prolonging of the TE1.Conclusion The MRI of ultrashort TE double pulse sequence may display the short T2 components that appeared as low signal with conventional clinical MR imaging, which made it pessible to quantify the tissues containing a majority of short T2 components.

Objective To describe MR findings in inflammatory myofibroblastic tumor(IMT)of the soft tissue.Methods MR manifestations of 11 cases of IMT of the soft tissue were retrospectively analyzed,and the MR findings were correlated with surgical and histological results.Results The pathological classification of the tumors was type Ⅰ in 1 case,type Ⅱ in 4 cases.mainly type Ⅱ admixed with type Ⅰ in 3 cases,and mainly type Ⅱ admixed with type Ⅲ in 3 cases.In 4 cases with primary tumor,the tumors were spheroid in shape,with well-defined margin and pseudocapsule.In 2 cases with primary axillary tumor and 5 cases with recurrent tumor,the tumors were irregular in shape,with ill-defined margin and invasion of adjacent structures.The tumors were mainly isointensive in T1-weighted images.Tumors of different pathological classifications had different signal intensities in T2-weighted images:1 case of type Ⅰ tumor was bright:4 cases of type Ⅱ tumor and 3 cases of type Ⅱ tumor admixed with type Ⅰ tumor were slig}ltly bright;3 cases of type Ⅱ tumor admixed with type Ⅲ were isointense or slightly hypointense in signal.All of the 11 eases in the study exhibited"pitaya cross-section sign"in T2-weighted sequence,which referred to discrete punctuate foci of relatively hypointensity in the background of hyperintensity,slightly hypointensity or isointensity.All of the 11 cases exhibited inhomogeneously significant enhancement after gadolinium administration.In the follow-up of the 6 cases of primary tumor,4 cases had recurrence,1 case had no recurrence,and 1 ease was lost in the follow-up process.In the follow-up of the 5 cases of recurrent tumor,4 cases showed recurrence again,and 3 cases were lost in the follow-up process.Conclusions The IMT of the soft tissue has characteristic MR features.The signal intensity of the tumor on T2-weighted sequence could reflect the pathological type of the tumor to some extent."pitaya cross-section sign"could be a pathogenomic sign of the IMT of the soft tissue.

Objective To analyses the magnetic resonance imaging(MRI)findings of different clinical patterns of neurosyphilis(NS).Methods Clinical records and MRI of 26 patients with NS were retrospectively studied.Results Abnormal MRI was found in 17 patients of 26 patients with NS.In 7 patients were with meningo-vascular syphilis,the MRI commonly showed multiple cerebral ischemia focus and cerebral infarction focus,very few similar to those of encephalitis;Six patients had general paresis,who presented cerebral MRI abnormalities of frontal and temporal atrophy,and few simultaneously with cerebral ischemia focus,granular apendymitis and hippocampus sclerosis;Three patients had syphilitic myelitis,their MRI showed mild tumefaction with multiple ischemic focus all the way through lower cervical spinal cord to lower thoracic spinal cord:One patient was with tabes dorsalis,whose cerebral MRI showed ischemic locus.Another 9 patients had normal MRI,of whom 4 patients with meningitis NS and 5 with tabes dorsalis.Conclusion The MRI of neurosyphilis has diverse presentations,and clinicians should pay much attention to it.

Objective To study the imaging performance and mechanism of acute patellofemoral joint impingent syndrome.Meth-ods The MR images and clinical data of acute patellofemoral joint impingent syndrome were analysed retrospectively in 10 patients, which were confirmed by clinic .MRI and DR examination were performed in all patients,in which 6 patients had complete knee ar-throscopy material.The imaging performance and mechanism of acute patellofemoral joint impingent syndrome were summarized re-spectively.Results All cases had clear history of buckling ectropion trauma;Patellar dislocation or subluxation were detected in 9 cases on DR examination,10 cases on MRI;Patellar medial fracture or osteochondral fracture caused by acute slipped patella was de-tected in 1 case on DR examination,2 cases (3 places)on MRI;Medial patellar retinaculum injury were detected in 10 cases on MRI,which were corresponding to that on surgery.Articular injury and subchondral marrow edema in particular parts of joint (an-terolateral of lateral femoral and medial patellar)were detected in 9 cases on MRI.MRI features of articular cartilage injury were confirmed by arthroscopy.MRI showed ACL or PCL injury in 3 cases,meniscus tear in 4 cases,which were quite consistent with the arthroscopy findings.Conclusion MRI can effective display joint cartilage damage,subchondral marrow edema in particular parts of the joint,which is useful to clinical prediction and treatment at early stage.

Objective To investigate the application significance of 3.0T MR three dimensional double-echo steady state(3D-DESS) and three dimensional-true fast imaging with steady-state procession(3D-True FISP) sequences in diagnosis of wrist cartilage of rheumatoid arthritis (RA).Methods 26 patients who were clinically diagnosed with RA underwent wrist MR scans with 3D-DESS and 3D-True FISP sequences, while both sequences' scanning were achieved on 20 of them.340 articular-surface morphological conditions' were observed,which were divided into level 0, level 1 and level 2 damages according to morphological performance,and recorded on 3D-DESS and 3D-True FISP sequence respectively.The diagnostic differences in the number of lesions were compared for two sequences.Results The numbers were 79 and 50 for level 1 damage and 23 and 33 for level 2 damage on 3D-DESS and 3D-True FISP sequence respectively (P<0.05).The artifacts were showed in 14 patients on 3D-True FISP,and only two patients on 3D-DESS.Conclusion 3D-DESS sequence does better than 3D-True FISP in displaying RA wrist cartilage,which is able to provide certain help for treatment and prognosis evaluation of RA.

Objective To explore the relationship between MRI and VEGF&CerbB-2 expression in atypical breast cancer.Methods 82 cases of atypical breast cancer confirmed by pathology were analyzed retrospectively.The relationship between MRI and VEGF &CerbB-2 expression were compared and analyzed.Results In total patients,57 cases were VEGF positive expression(69.5%,57/82),50 cases were CerbB-2 positive expression(61.0%,50/82).The VEGF positive expression rate was 78.8% in maximum diameter ≥2.0 cm group,which was obviously higher than < 2.0 cm group(P<0.05).Internal necrosis,ADC value and VEGF positive expression were positively correlated (P<0.05).There were not positively correlated relationships between internal reinforcement method,TIC and VEGF positive expression(P>0.05).There were positively correlated relationships between internal necrosis,ADC value and CerbB-2 positive expression (P<0.05).There were not positively correlated relationships between maximum diameter,internal reinforcement method, TIC and CerbB-2 positive expression(P>0.05).Conclusion There are relationships between the maximum diameter,internal necrosis,ADC value and molecular biology (VEGF,CerbB-2)of the atypical breast cancer.

Objective To demonstrate the feasibility of DTI in human calf with body phased-array coil and surface coil of spine as receiving coil on 3 T system, and to optimize the parameters of sequence, including slice thickness and b-value. Methods Fifteen healthy volunteers were recruited in this study and randomly divided into three groups. The DTI sequence for head was performed on calf in the first group (5 cases), and the sequence parameters were optimized based on the deficits of the raw and the post-processed DTI images. Then, different slice thickness were applied in the senond group (5 eases) to optimize the slice thickness, and this optimized parameter with the highest score based on quality of the post-processed DTI images was applied in the next step. Finally, different b values were applied in the last group to optimize this parameters. The b value with the highest score based on the quality of the pest-processed was the proper one. Results Three problems existed in the raw and the pest-processed images, when the DTI sequence for brain was used for the calf. First, the SNR of raw images is extremely low. Second, the muscle were unclear on the image with parts of signal lose, especially in the anterior tibialis muscle. Finally, the artifacts due to chemical shift and ghost are quite serious. The scores for muscle display quality with slice thickness of 4 mm , 5 mm and 6 mm were (7.0±0. 0), (8.6±0. 9) and (9.0±0. 0) score respectively, the signal less scores were (5.0±0. 0) and ( 12. 8±2. 6) and ( 13. 8±2. 2) score respectively, and the general score were (22. 0±0. 0) and (30. 1±3.8) and (31.0±4. 1 ) score respectively. The differences of above scores were significant among different slice thickness (F-value were 21. 000 and 30. 544 and 12. 390 respectively, P <0. 05 ). The muscle displaying quality, signal loss and general scores were lowest in group with 4 mm slice thickness (q-value were 4. 896.6. 120,6. 327,7. 138,3. 863 and 4. 043, P < 0. 05 ) o The scores of muscle display quality, signal loss and general for b =400 s/mm2 were (9. 0±0. 0), ( 14. 0± 2. 2 ) and ( 33.0±2. 2 ) score respectively, which were lower than those with b = 800 s/ram2 [(7.0±0.0), (6.2±2.2), (21.8±3.4) score] and b=1000 s/mm2[(7.0±0.0), (5.0±0.0), (20.6±2.2) score] (q-value were 3.873,3.873,6.650,7.672,7. 101 and 5.917, P <0.05)o The scores of muscle displaying quality, signal loss and general for b =600 s/mm2 were (8.2±1.1 ), ( 13.0± 2. 3) and ( 30. 8±3. 8 ) score respectively, which were higher than those with b = 800 s/mm2 and b= 1000 s/nun2 (q-value were 3.873, 3.873, 5.797, 6.820, 5.326 and 5.917, P <0.05).There is no significant difference between b = 600 s/ram2 and 400 s/ram2 ( q-value were 2. 582 and 0. 852 and 1. 775, P > 0. 05 ). Conclusion Our preliminary findings indicate that it is feasible to perform DTI on human calf with 3 T MR. With body phased-array coil and surface coil of spine as receiving coil, the DTI sequence were optimized to acquire enough SNB with slice thickness of 5 mm and b-value of 400 s/mm2.

Objective To evaluate the value of DTI in mild articular cartilage injury in patellofemoral joint.Methods The DTI and arthroscopy data of 82 patients wih routine MRI diagnosed as mild articular cartilage injury were analyzed retrospectively.According to the results of arthroscopy,40 cases of mild articular cartilage injury with Outerbridge classification Ⅰ or Ⅱ were divided into experimental group,and 33 cases with normal patellofemoral articular cartilage were divided into control group.There were 8 articular cartilage injury patients with Outerbridge classification Ⅲ or Ⅳ in patello-femoral join were excluded.The DTI data were analyzed compared with arthroscopy.Results Arthroscopy detected 62 lesions of cartilage injury in experimental group.Totally 49 lesions (49/62,79.03 ％) were detected by ADC pseudocolor image and 51 lesions (51/62,82.25 ％) were detected by FA pseudocolor image.The DTI pseudocolor images of articular cartilage injury showed uneven levels.The red or pink levels can been observed.Compared with the control group,ADC value increased and FA value decreased significantly in experimental group (both P＜0.05).Conclusion DTI can clearly display and detect mild articular cartilage injury in patellofemoral joint,which provide valuable information for early cartilaginous injury.