Objective To compare the applications of half-Fourier acquisition single-shot turbo spin-echo(HASTE)sequence and true fast imaging with steady state precession(True FISP)sequence for the delineation of structures and diseases in several twin pregnancy with comorbidities and to explore the clinical value of two series of fast imaging for MRI of fetus.Methods 27 twin preg-nancy women with comorbidities were imaged with HASTE and True FISP sequences.All images were statistically analyzed in re-spect of imaging qualities and artifacts.MR signs of fetal brain were analysized.Results There were abnormal changes in brains in 7 of 27 cases.Both sequences could demonstrate the structures and lesions of the fatus.Imaging quality scores of HASTE were higher than that of True FISP,but with more respiratory blurring.Conclusion There might be varying abnormalities in central nervous system in twin pregnancy with comorbidities.Combining the demonstration abilities of HASTE and True FISP is needed when de-tecting fetus lesions,especially the brain.

PurposeTo explore CT and MRI findings of pigmented villonodular synovitis (PVNS) of spine, and to improve the preoperative diagnosis.Materials and MethodsCT and MRI findings of 7 cases of PVNS of spine confirmed by surgery and pathology were retrospectively analyzed. Seven cases underwent CT scan and 5 of them underwent MRI scan. The location of the lesions, tumor size, shape, density (signal), bone destruction and enhanced features were analyzed.ResultsExcept one case with small lesion, the remaining 6 cases showed lobulated soft tissue masses centering at the facet joint area, with lytic, expansive bone destruction. On CT images (n=7), 3 cases showed the masses density similar to that of the surrounding muscles, and 4 cases showed the tumor density slightly lower than that of the surrounding muscles. On MRI images (n=5), 1 small lesion demonstrated low signal at the peripheral, 1 lesion was isointensity without obvious low-density in it, 3 cases showed characteristic multiple visible low signal nodules in the lesions.ConclusionThe possibility diagnosis of the PVNS should be considered when spinal lesions are characterized by osteolytic bone destruction centering at facet joints and soft tissue masses with distinctive MR signals.

Objective To explore the effective approaches in information recognition rate improving for picture archiving and communication system (PACS) centralized printing system.Methods Possible factors that impact information recognition rate wereanalyzed,and then proposed the relevant optimizing solutions respectively by configuring the modality printing parameters and adjusting the radiology information system accession number (RIS ACCESSION NUMBER) matching rules.Results Effectiveness and accuracy were enhanced significantly through testing at Central Printing System by using these approaches.Conclusion These methods improve effectively the film information recognition rate and provide important technical support for digital imaging and communications in medicine (DICOM) centralized printing system.

Objective To present the CT and MRI findings of the fibrous dysplasia(FD) of the spine.Methods CT and MRI findings were retrospectively evaluated in 19 cases of FD of spine,all of which were confirmed pathologically.Nineteen patients underwent CT plain scanning(19/19) and 5 had enhanced CT scanning(5/19).Patients were also examined by MRI plain scan(11/11) or MRI enhanced scan (6/11).The location of tumors,the type of bone destruction,the boundary of lesions,internal intensity or signal,the enhancement pattern of lesions,and presence of compression fractures,spinal deformity were observed.Result Nine cases had monostotic FD,while 10 had polyostotic FD.In all the 49 lesions of 19 cases,13 lesions were located in the cervical vertebrae,23 lesions in the thoracic vertebrae,11 lesions in lumbar vertebrae,and 2 lesions in sacral vertebrae.Thirty-three lesions involved both vertebral body and appendix.Pure osteolysis were found in 26 lesions on CT examinations.Peripheral osteosclerosis rims (41/49) and expansive lesions(32/49) were seen.Residual bone crest(28/49) and ground-glass opacity(23/49)were noted.Different degrees of vertebral compression were found in 19 lesions.Five patients had spinal deformity.On T1WI,14 lesions showed intermediate or low signal,and 10 lesions presented as heterogeneous signal.On T2WI,6 lesions had low signal intensity,4 lesions were noted as hyperintensive,and 14 lesions presented as heterogeneous signal.Multiple fluid-fluid levels were found in 1 lesion.Low signal rims were seen in 14 lesions.Twenty lesions of 11 patients had significant enhancement.Conclusion Expansive pattern,ground-glass opacity,peripheral osteosclerosis rims and significant enhancement were helpful findings for the diagnosis of spinal FD.

Objective To discuss the CT and MR imaging appearances and diagnostic value of spinal lymphoma. Methods Sixteen patients with pathologically proved spinal lymphoma (aged 8 to 63 years) were retrospectively reviewed. CT were performed in all 16 patients, and MRwere performed in 12 patients. Results Totally 65 vertebrae (cervical 15, thoracic 22, lumbar and sacrum 28) were involved. Multiple lesions were found in 11 patients. The characters of these lesions were osteolytic, osteogenic or mixed on CT. The signal intensity was hypo or iso on T1WI and iso or slightly hyper on T2WI. The extradural involvements were more extensive than that of the vertebrae both on CT and MR images. Conclusion Lesions of spinal lymphoma usually demonstrate various bone destructions on CT, and hypo or iso intensity on T1WI as well as iso or slightly hyper intensity on T2WI, tending to involve paraspinal or extradural space, and longitudinal involvements are often seen along the vertebral canal. MRI is more sensitive than CT in detecting spinal lymphoma lesions.

Objective To evaluate the effect of reference mAs on radiation dose and image quality characteristics of chest CT scanned with CARE kV technique compared with CARE Dose4D.Methods According to the date of examination,158 consecutive patients were selected in our department and randomly divided into 5 groups:CARE Dose4D group (30 cases,group 1); using CARE kV technology,reference mAs were 110 (32 cases),90 (31 cases),70 (33 cases),50 (32 cases),which were recorded asthe group from 2 to 5,respectively.Volume CT dose index (CTDIvol),dose length product (DLP) and the effective dose (ED) were analyzed.CT value and objective image noise were measured in the lungparenchyma and descending aorta.Two radiologists assessed the images for subjective noise,artefacts and diagnostic acceptability.The radiation dose,CT value and objective noise were compared with the analysis of variance,and the difference between two groups was compared with SNK test; the rank sum tests (Kruskal-Wallis) were used in subjective image quality score,and difference between two groups was compared with K-W test.Results The CTDIvol,DLP,ED values in five groups were (7.7±1.7),(7.7±2.0),(5.5±1.4),(4.2±1.5),(2.8±1.2)mGy,(290.7±67.4),(290.1±85.2),(194.2±52.1),(150.7±63.8),(96.5±38.9) mGy· cm,(4.1±0.9),(4.1±1.2),(2.7±0.7),(2.1 ± 0.9),(1.3±0.5) mSv,respectively.There were significant difference among the 5 groups(F=59.305,57.76,57.76,P＜0.01).With the decrease of the reference mAs,the radiation dose decreased significantly.There were no significant difference among the 5 groups on the average CT values of lung parenchyma and descending aorta(F=0.353,0.102,P＞0.05).The objective noise of 5 groups in pulmonary parenchyma and the descending aorta were (48.7 ± 9.1),(49.2 ± 10.0),(55.5± 11.2),(56.5± 8.3),(63.7 ± 13.2) HU; (9.2± 1.6),(9.5 ± 2.1),(10.7 ± 2.6),(11.6 ± 2.7),(13.6 ± 2.6) HU respectively,and the difference was significant(F=10.774,17.157,P＜0.01).Level assessment onsubjective noise of five groups by radiological expertsalso showed the significant difference (U=33.967,P＜0.01),butthe evaluation on motion,streak,blotchy pixellatedartefacts and diagnostic acceptability had no statistical difference (U=8.847,2.054,6.186,5.296,P＞0.05).Conclusion Comparedwith CARE Dose4D,the use of CARE kV technique of suitable reference mAs for unenhanced chest CT can reduce radiation dose significantly with diagnostically acceptable image quality.

Objective To summarize MRI features of anterior cruciate ligament graft tear and to explore the differences of MRI findings between acute tear and chronic tear, and compare the diagnostic ability of MRI and clinical examinations for graft tear. Methods MR images of 43 patients (44 knees) with anterior cruciate ligament graft tear(40 complete tear, 4 partial tear)confirmed by secondary arthroscopy were retrospectively analyzed. There were 18 acute tear and 26 chronic tear. Primary and secondary signs reported with conventional anterior cruciate ligament tear were adopted to evaluate graft tear. The exact probability method was used to compare the prevalence difference between various direct and indirect signs and the χ2 test was used to compare the accuracy between MRI and physical examination. Results The primary signs in MR images of anterior cruciate ligament graft tear included graft discontinuity in 13 kness, graft thickening with edematous high signal intensity in 12 knees, decreased slope of graft fibers in 6 kness, graft disappearing in 5 knees, and distinct graft atrophy in 3 knees. The secondary signs included kissing bone contusion in 4 knees, posteriorcruciate ligament buckling in 3 knees, increased anterior tibial displacement in 2 knees, bone contusion of the lateral condyle of femur, and bone contusion of thetibia condyle in 1 knee, respectively. There were no significant differences regarding the proportion of each sign between acute and chronic graft tear. Accuracy of MRI, Lachman test, and anterior drawer test were 87.5%(35/40), 95.0%(38/40)and 95.0%(38/40), respectively, which were all significantly higher than that of pivot shift test(42.5%,17/40) with significant differences(χ2=17.80, P<0.0083). Conclusions MRI is sensitive for diagnosing anterior cruciate ligament graft tear, the primary signs is the main evidence for the diagnosis of ACL graft tear, but it is hard to distinguish acute and chronic graft tear based on MR findings. The diagnostic accuracy has no statistically significant differences among MRI, Lachman test, and anterior drawer test, but they are all higher than pivot shift test.

Objective To study the CT and MRI features of the chordoma in the mobile spine.Methods The CT and MRI fea-tures were retrospectively analyzed in twenty-four cases of chordoma in the mobile spine.Results In all the twenty-four cases,bone lesions were solitary in eight cases and multiple in sixteen cases,mostly occurred in cervical,occasionally occurred in thoracic or lum-bar vertebra.Both vertebral body and part appendix were involved in all cases.CT imaging showed that all the lesions mainly mani-fested as osteolytic bone destruction,peripheral osteosclerosis and the cortical bone were incomplete.Soft-tissue mass involved para-vertebral and intraspinal.Five lesions appeared vertebrae compression.Eight lesions appeared intervertebral foramen expansion.Le-sions appeared honeycomb or annular enhancement after contrast media injection.Lesions were presented as heterogeneous slightly hypo-isointensity on T1 WI,hyperintensity on T2 WI.Low signal fibrous septa within the tumors were seen.Lesions appeared hon-eycomb enhancement after Gd-DTPA injection.Conclusion CT and MRI findings of chordoma in the mobile spine can be regarded as characteristic,which are helpful for clinical diagnosis.

Objective To investigate the feasibility, short-term efficacy and adverse effects of 125 I seed implantation guided by ultrasonography or CT in the treatment of recurrent rectal cancers. Methods A total of 15 patients (4 women and 11 men) with recurrent rectal cancer entered the study. Uneer epidural anesthesia, the patients were treated with 125 I seed implantation under the guidance of either transvaginal ultrasonography or CT scans. The prescribed matched peripheral dose (MPD) was 90~110 Gy, with an activity per seed of 0.50~0.70 mCi and the total number of sources implanted of 33~70. Chest and pelvic X-ray examinations were performed within 24~48 hours after implantation to determine whether or not seed misplacement or migration existed. An additional three-dimensional conformal radiation therapy with a 4~6 fields technique was required in 6 patients 4 weeks postoperatively, with 200~300 cGy/fx, 5 fx/week, up to a total dose of 4500~5 000 cGy. Additional chemotherapy with oxaliplatin, 5-fluorouracil and tetrahydrofolic acid for one treatment course was given in 2 patients. The patients were followed for 3~15 months and the tumors were evaluated by CT findings. Results Relief from pain was achieved at a mean of 7 days after procedure, offering a complete relief in 12 patients, a partial relief in 2, and no change in 1, the effective rate being 93%(14/15). Nine patients showed a complete remission, 2 showed a partial remission, 4 showed a progressive disease, the local control rate being 73%(11/15). Two patients died of the dissemination to lungs. In 1 patient 1 seed had migrated to the pelvic side-wall and did not cause any clinical morbidity in a follow-up of 12 months. Conclusion 125 I implantation in recurrence of rectum cancer guided by ultrasonography or CT was safety, minimally invasion, low morbidity and high efficacy, it was worth of development and promotion.

Objective To discuss the selection of approaches for CT-guided percutaneous biopsy of thoracic and lumbar spine. Methods One hundred and forty-one cases of thoracic (70 cases) or lumbar (71 cases) vertebral undiagnosed lesions underwent CT-guided percutaneous biopsy. Appropriate needle approaches were designed according to different locations of lesions in the vertebra, including 63 cases of paravertebral path, 45 cases of transpedicular path, 11 cases of transcostovertebral path, and 22 cases of other paths. Results Out of the 141 cases, a definite diagnosis was obtained in 128 cases. The diagnostic accuracy of biopsy was 90.8%. No complications occurred. Conclusions The needle approach for CT-guided percutaneous biopsy of the thoracic and lumbar spine should be selected according to different locations of lesions, which should be based on principles of safety, enough specimen, and minimally invasive to patients.