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.

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 explore the efficacy of prophylactic bilateral internal iliac arteries balloon occlusion in treatment of women with pernicious placenta previa complicated with placenta accreta.Methods A retrospective analysis was conducted on 41 cases of pernicious placenta previa with placenta accreta admitted to Guangzhou Women and Children's Medical Centre from January 2010 to December 2012.The study group (n=13) underwent prophylactic bilateral internal iliac arteries balloon placement before cesarean section and occlusion after delivery.The control group (n =28)received conventional haemostasis during cesarean section.The amount of blood loss and blood transfusion during the operation,the perioperative hemoglobin level,operation time and duration of hospitalization of the two groups were compared with t test or Chi square test.Results The volume of intraoperative hemorrhage of the study group was lower than of the control group [(1429±875) ml vs (4600± 2090) ml,t=6.840,P=0.000],the amount of intraoperative blood transfusion in the study group was also lower [(920±438) ml vs (3600± 1225) ml,t=10.251,P=0.000].Operation time and postoperative duration of hospitalization of the study group were shorter than those of the control group [(197±45) min vs (284±44) min,t 5.850,P=0.000; (6.7±1.3) d vs (8.2± 2.2) d,t=2.272,P=0.029].There was no statistical difference on hysterectomy rate between the two groups [11/13 vs 89％(25/28),x2=0.181,P 0.670)].In addition,two cases of reoperation,one case of pulmonary edema,two cases of coagulation disorder,one case of venous thrombosis in lower limbs,one case of renal dysfunction and pulmonary edema were reported in the control group,but none in the study group.Conclusions.Prophylactic bilateral internal iliac arteries balloon occlusion is effective in reducing intraoperative blood loss,transfusion,and relative complications in patients with pernicious placenta previa complicated with placenta accreta.

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 CT and MRI features of Langerhans cell histiocytosis (LCH) with multiple spinal involvement.Methods The CT and MRI data of 13 patients with multiple LCH lesions in spine confirmed by pathology were retrospectively analyzed.All of 13 cases underwent CT examination (1 case underwent enhanced scanning) and 12 cases underwent MR examination (6 cases underwent enhanced scanning).Results In 13 cases,there were 8 cases of single central lesions invading the adjacent vertebrae and 5 cases of multiple central lesions.There were 19 core spinal lesions and 15 adjacent invading lesions in a total of 34 vertebrae lesions.Eighteen core lesions (18/19,94.74 ％) had different degrees and shape of vertebral compression.A total of 34 abnormal vertebrae were found in 13 cases by CT,which were manifested as osteolytic bone destruction.Eighteen cortical bones of 19 core vertebrae were incomplete,and a paravertebral soft-tissue masses were observed.There were 33 vertebrae lesions in 12 patients who underwent MR examination,including 18 core spinal lesions and 15 adjacent invading lesions.The lesions displayed equal,slightly lower or low signal on T1WI,slightly higher or high signal on T2WI and high signals on fat suppression sequences.A paravertebral soft-tissue masses were observed in 17 core spinal lesions (17/18,94.44％).Conclusion CT and MRI manifestations of spinal multiple LCH have certain characteristics.The level of diagnosis and differential diagnosis should be improved by deepen understanding of the disease image performance,but the diagnosis still depends on the pathology.

Objective To detect the application value of the apparent diffusion coefficient (ADC) values using diffusion weighted imaging (DWI) in detection of fetus with enlargement of cisterna magna.Methods Sixteen fetuses with enlargement of cisterna magna (group 1) and other sixteen healthy controls (group 2) were scanned by DWI.The ADC values were measured and compared between two groups at the same regions, and between left and right brain in group 1.The correlations between ADC values,the enlarged degree of cisterna magna and gestational age were calculated respectively.Results The ADC values were lower in the white matters of bilateral frontal lobes and parietal lobes, bilateral thalami and cerebellum in group 1 than those in group 2.There were no significant differences in ADC values between left areas and right areas in group 1 (P>0.05).The ADC values in bilateral basal ganglia and thalami were negatively correlated with the gestational age (P<0.05).There was no correlation between the enlarged degree of cisterna magna and gestational age (P>0.05).Conclusion The ADC values were decreased in certain regions in fetuses with enlargement of cisterna magna, which suggested that ADC value might be more sensitive for detecting potential damage of brain.Combined with conventional MRI, DWI and ADC values could be regarded as accurate protocols for the detection of fetus abnormalities.

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.

Objective To analyze the selection of puncture needles in CT-guided percutaneous biopsy in musculoskeletal system diseases.Methods Three hundred and sixty-four undiagnosed lesions of musculoskeletal system underwent CT-guided percutaneous biopsy from January 1996 to March 2005.Proper selection of different puncture needles,including biopsy gun,bone biopsy needle,or both,was made according to different locations and characteristics of the lesions.Results Among 255 lytic lesions,the biopsy gun alone was used in 47 cases and both biopsy gun and bone biopsy needle were used in 208 cases.Among 73 mixed lesions,the bone biopsy needle alone was used in 49 cases,biopsy gun alone in 14 cases,and both in 10 cases.The bone biopsy needle was used in all 36 sclerotic lesions.Enough specimens were obtained in all the cases,and no complications occurred.A correct biopsy diagnosis was made in 334 cases,the diagnostic accuracy of biopsy being 91.8%(334/364). Conclusions The puncture needles for CT-guided percutaneous biopsy of the musculoskeletal system lesions should be selected according to different locations and characteristics of lesions.For sclerotic lesions or lesions containing relatively more sclerotic contents,the bone biopsy needle should be used.For lytic lesions,the biopsy gun should be used.And the combined use of both bone needle and biopsy gun should be utilized for mixed lesions.

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 report a new designed technique of CT-guided percutaneous puncture for atlantoaxial lateral mass arthrodesis with bone graft and discuss its clinical usefulness and effect. Methods From March 1999 to March 2001, on the base of anatomical investigation of 56 adult cadaversatlas and axis bone specimens, 9 cases with instability of atlantoaxial were treated after reduction by traction, 4 of 9 cases underwent Halo-Vest immobilization, and the other 5 cases underwent transarticular screw fixation through C2 vertebral body for atlantoaxial instability. Of all nine cases, the articular cartilage and capsule of post lateral part of atlantoaxial joints were removed by using home made surgical instruments under CT guidance. Iliac cancellous bones obtained by puncture were implanted into the joint space. Results All cases were followed up from 2 to 17 months (average 12.7 months) and 8 cases more than 6 months. Generally, at the third to fourth month after operation, CT scan showed bony union of the grafted bone and the excessive extension and flexion X-ray films showed stable movement of the atlantoaxial joints, and then the Halo-Vest stock were removed. Conclusion This technique has obvious advantages of less trauma and hemorrhage, high union rate, easy, safe and efficiencies.