Objective To study the effect of iterative algorithm (iDose algorithm) on image quality and radiation dose in paranasal sinus MSCT.Methods A proper cadaveric head based on the average CNR (contrast noise ratio) of paranasal sinus images in 53 patients was applied.The cadaveric head was scanned with different parameters of kV and effective mAs.The images were reconstructed with filtered back projection and iterative algorithm (iDose 1-7) respectively.The subjective and objective evaluations were performed for all the images and the optimal parameter combination was found out.Results The CNR of coronal images was slightly higher than that of axial images (t =-6.86,P ＜0.05).The image CNR of protocol (120 kV,100 mAs/slice and iDose5) was close to that of conventional protocol.The protocol of 100 kV,60 mAs/slice and iDose4 offered the images adaptable for diagnosis of inflammation.The protocol of 100 kV,80 mAs/slice and iDose4 offered the images adaptable for diagnosis of inflammation and fracture,and the radiation dose were reduced by 82％ and 75％,respectively.Conclusions Using the iDose algorithm could help to offer diagnostic images for inflammation and fracture and reduce the radiation dose in the paranasal sinus MSCT.

Objective To evaluate the effect of neuromuscular electrical stimulation (NMES) on swallowing function in brain injury patients with dysphagia.Methods Sixty-four patients with dysphagia were divided into A group (n=21,stimulated with T =700 ms,R =2 s,frequency =0.19 Hz),B group (n =22,T =700 ms,R =1 s,frequency =0.29 Hz),and C group (n =21,T =340 ms,R =400 ms,frequency =0.68 Hz).One pair of electrodes was placed at the midline under the chin over the submental muscle group.The intensity of stimulation ranged from 5 to 11 mA.The treatments were once a day,5 times a week,with 20 times as one course.The results were assessed with Kubota's water swallowing test before and 4 weeks after treatment.Results The water swallowing test scores were significantly reduced after treatment in all 3 groups,with significantly greater reductions in A group compared with B and C group.The effectiveness rate was 81％ in A group,73％ in B group and 67％ in C group,all statistically significant differences.Conclusion NMES can be an effective and safe treatment for dysphagia after brain injury.NMES appears to be most effective with T =700 ms,R =2 s,and a frequency of 0.19 Hz.

Acupuncture Points ; Adolescent ; Adult ; Electroacupuncture ; Female ; Humans ; Male ; Middle Aged ; Spinal Cord Injuries ; complications ; Urinary Bladder, Neurogenic ; etiology ; physiopathology ; therapy ; Urination ; Young Adult

BACKGROUND:Extradural cortical stimulation combines the advantages of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, subdural cortical stimulation and deep brain stimulation, which can significantly improve motor and language function after stroke. OBJECTIVE:To review the theoretical research and clinical application of extradural cortical stimulation for stroke recovery. METHODS:An online retrieval of PubMed database and CNKI database between January 1995 and April 2014 was performed for articles on theoretical research and clinical application of extradural cortical stimulation for stroke recovery, with the key words of“cortical stimulation, extradural motor cortex stimulation, extradural cortical implants, extradural cortical stimulation, stroke, rehabilitation”in English and Chinese. RESULTS AND CONCLUSION:Because of implantable cortical stimulation, the advantage of extradural cortical stimulation is its minimal invasiveness, high accuracy and transdural contact with the brain. For lack of effective treatment for the chronic phase of stroke patients with motor and language dysfunction, extradural cortical stimulation may be a new therapeutic method. Motor and language functional improvement must derive from reactivation of plasticity, local enhancement of perilesional areas, enhancement of network function and inter-hemispheric balance function, and amplification of sensory input.

Objective To study the impact on the radiation dose,organ doses of eye lens and thyroid and image quality with different scanning modes in head and neck CT scan.Methods The simulation phantom of head and neck was scanned by using fixed scanning condition (120 kV and 200 mAs),as well as the combinations of automatic tube current modulation (CARE Dose 4D),automatic tube voltage modulation technique (CARE kV) and partial angle scanning mode (X-CARE) respectively.Six kinds of scanning modes were adopted,including 120 kV +200 mAs,120 kV + 200 mAs + X-CARE,CARE Dose 4D + 120 kV,CARE Dose 4D + 120 kV + X-CARE,CARE Dose 4D + CARE kV,CARE Dose 4D + CARE kV + X-CARE.Two thermolumineseece dosimeters (TLDs) were exposed at the skin surface positions of eye lens and thyroid,and the values measured with two TLDs were averaged.The CT dose index volume (CTDIvol) and dose length product (DLP) for every scan were recorded,and the contrast to noise ratio (CNR) in eye lens section and thyroid section were measured.Results The crgan doses of lens and thyroid were 19.8 and 26 mGy at 120 kV and 200 mAs,as well as 13.3 and 22.2 mGv at X-CARE mode.Compared with the manual selection of 120 kV,the combination of CARE kV and CARE Dose 4D made the values of CTDIvol drop from 13.1 to 10.1 mGy,the doses of eye lens and thyroid from 16.6 and 20.8 mGy to 23.7 and 19.9 mGy respectively,while the image quality reducedsignificantly.Compared with CARE Dose 4D + 120 kV,the organ doses of eye lens and thyroid were reduced from 20.8 and 23.7 mGy to 9.6 and 15.1 mGy for with additional X-CARE,while CTDIvol dropped from 13.1 to 9.3 mGy.When the combination of CARE Dose 4D + CARE kV + X-CARE was used,CTDIvol and organ doses were reduced to a minimum,when the CNRs of head and neck were also minimized.Conclusions The scanning mode CARE Dose 4D + 120 kV + X-CARE for head and CARE Dose 4D + CARE kV for neck can effectively reduce the radiation dose while keeping good image quality.When requirements for image quality are not high,CARE Dose 4D + CARE kV + X-CARE mode can be selected to reduce the radiation dose significantly.

Objective To explore the effects on image quality and dose reduction to the lens when using bismuth shielding in head and neck MSCT.Methods The standard phantom and the cadaveric head with none,1,2 and 3 layers of bismuth shielding were scanned with protocols of brain,temporal bone and paranasal sinuses using a 16-MDCT scanner.The organ dose to the lens in each scanning was measured with thermoluminescence dosimeters(TLD).The above scanning with sinus protocol was repeated with a sponge with thickness of 5,10,15 and 20 mm placed between the shielding and phantom/head.The CT attenuation of phantom with the distance of 2,4,6 and 8 cm to shielding were measured.The image quality was subjectively evaluated by 2 physicians.Results The organ doses of the lens with protocols of brain,temporal bone and sinuses were 24.31,27.60 and 20.01 mGy,respectively.The doses were decreased significantly when using bismuth shielding.With the increase of the shield gap,the degree of dose reduction was reduced,but the increasing degree of CT attenuation significantly reduced.Using 2-layer and 3-layer bismuth shield in brain and temporal bone CT scan,the radiation doses were reduced by 47.1％ and 59.1％,respectively while maintaining the diagnostic image quality.Using 1-layer shield without gap and 2-layer shield with 1.5 cm gap in sinus CT,the radiation doses were reduced by 31.5％ and 34.5％,respectively.Conclusions Reasonable usage of bismuth shielding can effectively reduce the radiation dose to the lens of eye in head and neck MSCT.

Objective To explore the influence on image quality and the reduction of radiation dose to eye lens when using bismuth shielding in sinus MDCT.Methods The standard water phantom was scanned using clinical scanning protocols of sinus in 16-MDCT,and the images were acquired with none,1 layer,2 layers and 3 layers of bismuth shielding severally.Using the above protocol,the cadaveric head was scanned with no shield,1,2 and 3 layers of bismuth shielding material covered on both eyes,and the organ dose to eye lens in each scanning was measured with thermoluminescence dosimeter (TLD).The sponge with the thick of 0.5,1.0,1.5,2.0 cm was placed between the shielding material and the surface of subjects separately and the radiation doses to eye lens was measured with sinus scanning conditions in the same way.The CT values of phantom with the distances of 2.0,4.0,6.0 and 8.0 cm to shield material were measured.The influence of bismuth artifacts on anatomic structures was evaluated as well.Results The organ doses to the eye lens in the sinus clinical CT were 20.0 mGy.Doses decreased significantly to 13.7,10.9 and 9.4 mGy separately when using 3 types of bismuth shielding thickness.With different thicknesses of shielding material,the greater the shield gap,the smaller the degree of reduction of organ dose,but the increasment of CT value was significantly reduced.Using 1-layer shield no gap and 2-layer shield with 1.5 cm gap in sinus MDCT,the radiation doses were reduced to 13.7 and 13.1 mGy with the reduction rates of 31.5％ and 34.5％ respectively.Conclusion The reasonable bismuth shielding can effectively reduce the radiation dose to eye lens in sinus CT on the premise of ensuring image-diagnostic quality.

Objective To explore the distribution characteristics on z-axis of scattered radiation from a wide-detector CT with different scan modes and detector widths.Methods The CT standard-dose phantom was scanned using a 16 cm wide detector Revolution CT.Thermoluminescent dosimeters (TLDs)were placed on the central axis (z-axis) of the scan hole at given intervals.As scan modes,both axial scan mode (using detector with width in 4,8 or 16 cm) and the helical scan mode (using detector with width in 4 and 8 cm) are used.The scan parameters were as follows:tube voltage 120 kV;effective tube current 200 mAs;scan length 16 cm;pitch (for helical scan):0.984 ∶ 1 and 0.516 ∶ 1,and all scans were repeated for 4 times.All TLDs were measured,after exposure,and divided by four for further analysis.Results The scattered radiation on z-axis was higher at the direction of human head than at the direction of human foot (Z=-2.366,-2.197,-2.366,-2.371,-2.028,-2.236,-2.028,P＜0.05).Under the axial scan,the difference in distribution of scattered radiation with different detector widths was statistically significant.The maximum increase for detector width of 4 cm and 16 cm was 67.5 μ Gy(x2=28.000,P＜0.05).Under the helical scan,the difference in distribution of scattered radiation with different detector widths was statistically significant (Z =-3.233,-2.982,P＜0.05).The largest distribution of scattered radiation was found when the detector width was 8 cm and the smallest at the detector width is 4 cm.The maximum increase for detector width of 8 and 4 cm was 97.67 μGy at a pitch of 0.516 ∶ 1.Furthermore,when the detector width and effective mAs were the same,the scattered radiation at a pitch of 0.516∶1 was greater than that at a pitch of 0.984 ∶ 1,with the statistically significant difference(Z =-3.296,-3.296,P＜0.05).The maximum increase was 49.95 μGy when the detector width was 8 cm.Conclusions In a 16 cm wide-detector CT,the selection of different detector widths can significantly influence the distribution of radiation field and related radiation values.Suitable detector width and relevant parameters shall be chosen according to the specific clinical requirements so as to reduce the radiation doses to workers,patients and carers.

Objective:To investigate the effect of organ dose modulation (ODM) technique on reducing the breast radiation dose in chest CT scanning.Methods:In the phantom test, the PBU-2 adult chest module was used. The clinical chest scan protocol was used and three sets of scans performed on the chest module： (1) ODM off group, ODM was not used; (2) ODM part group, ODM was applied only in the breast region； (3) ODM all group, ODM was applied in the whole scan scope. Other scan parameters were same for the three groups, with smart mA applied. The volume CT dose index (CTDI vol) was recorded for all three groups. A long rod ionization chamber was placed in a fixed position in front of the right breast area to measure the breast skin dose (D). The contrast noise ratio (CNR) and the figure of merit (FOM) were measured respectively. In clinical research, 72 female patients who underwent chest CT scanning in Beijing Tongren Hospital Capital Medical University from August to November 2018 were retrospectively recruited. According to the application of ODM, the patients were divided into ODM off group (without ODM, 36 cases) and ODM part group (ODM applied in the breast region, 36 cases). The CTDI vol and the dose length product (DLP) were recorded. CNR, noise of images were measured and calculated, respectively. The image quality was evaluated by subjective evaluation scores. The one way ANOVA analysis was used in comparing the difference of CNR among the 3 groups in module test. As for clinical cases, the independent samples t test was used to compare the difference in CTDI vol, DLP, CNR and the noise between two groups; and the rank-sum test was used for comparison in image quality subjective evaluation. Results:In module test, the radiation dose was highest in ODM off group, and lowest in ODM all group. The CTDI vol were (6.90±0.02), (6.26±0.02) and (5.99±0.02) mGy, and the D values were (9.17±1.01), (8.01±0.92) and (7.58±0.87) mGy for ODM off group, ODM part group and ODM all group respectively. The CNR values of images with soft tissue algorithm reconstruction were highest in ODM off group and lowest in ODM all group, while no statistically significant difference was displayed ( P>0.05). The CNR values of the images with lung algorithm reconstruction showed the same trend, with statistically significant difference among the three groups ( F=154.732, P=0.006). The FOM of the lung and soft tissue algorithm images was maximized when the ODM was partially applied. As for clinical cases, compared with ODM off group, the dose of ODM part group showed significantly decreased, with CTDI vol decreased by 16.12% ( t=2.604, P=0.011), and the DLP decreased by 16.85% ( t=3.293, P=0.002). No significant difference was found in CNR, noise and subjective score by two doctors between two groups ( P>0.05). Conclusion:The application of ODM in chest CT imaging can reduce the radiation dose of breast with simultaneously maintaining the image quality.

Objective:To investigate the effect of different scanning modes, detector width and location in detector on high and low contrast resolution of wide-detector CT image.Methods:The Catphan600 phantom with high and low contrast resolution modules was scanned with GE Revolution CT at the same CTDI vol. The scans were performed with the detector widths of 40, 80 and 160 mm for sequential scanning mode and with the detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 for spiral scanning mode. The resolution modules were placed at the adjacent region between two sequential scans, central and foot side edge in the longitudinal scanning range seperately. The subjective evaluation of the high and low contrast resolution was performed by two radiologists. Results:The high contrast resolution was 8 LP/cm at adjacent region between two sequential scans with the detector width of 80 mm or 160 mm in sequential scanning mode, and at the pitch of 0.5 in spiral scanning mode, while it was 7 LP/cm for the rest of detector combinations. The distinguishable diameter was 3 mm at 1% low contrast resolution at foot side edge with the detector widths of 80 mm or 160 mm in the sequential scanning mode, and it was 2 mm for all the other conditions. The distinguishable diameter was 2 mm at 1% low contrast resolution with the detector width of 40 mm and pitch 0.516 in the spiral scanning mode and it was worse with the wider detector and larger pitch.Conclusions:For the wide-detector CT, scanning mode, detector width, location in detector and pitches will affect the high and low contrast resolution to some degree. Appropriate selection should be done according to actual needs in clinical practice.