Objective To study the half quantitative diagnostic method of the high-risk gastrointestinal stromal tumors (GISTs) with analyzing the characteristic of high-risk and lower risk GISTs with multi-slice spiral CT (MSCT). Methods CT findings of 46 patients with 51 GIST lesions were retrospectively analyzed. The location, size, shape, boundary, growth pattern and other specialties of the tumors in high-risk and lower risk GISTs were studied, moreover statistical analysis was conducted, logistic regression equation was obtained. Results Significant difference was found in tumors' location, size, shape, boundary and distant metastasis between the two types of GISTs. There were obvious correlation between the risk level and tumors' size and boundary which could be used to build the diagnostic equation of high-risk GISTs. Conclusion The equation ln [P/(1-P)]=-2.612X_3+0.371X_5 (X_3:tumors' boundary, X_5:tumors' size) is valuable in the diagnosis of high-risk GISTs.

Objective To examine the epidemiological and clinical features of the adults with Henoch Schonlein Purpura (HSP),and improve the diagnosis and therapeutic efficacy of HSP.Methods Thirty five adults with HSP from the hematological department of Tianjin Medical University General Hospital between 1993.9 to 2005.12 were enrolled in this study.Epidemiological,clinical and laboratory data,therapeutic methods and efficacy were investigated.Results Most patients with HSP in our department were male and adolescent.HSP occurred more commonly in the winter.The important predisposing factors were infection and having specific food.Purpuric lesions were the most common presenting signs.Multiple organ involvement was more common.Purpura was present in all case,lower extremities were more commonly involved.Joint involvement was observed in 15 cases(42.9%),abdominal involvement in 20 cases(57.1%),renal involvement in 20 cases(57.1%).Conclusion The adult patients with HSP had more tendenecy to have severe renal damage and multiple organ involvement.

Objective To probe the cause,clinical and imaging findings of children's congenital pyriform sinus fistula (CPSF). Methods Clinical and radiographic data in 23 patients with children’s CPSF were analyzed retrospectively which were confirmed by pathology.Results 1 6 patients represented repeated swelling and pain in left anterior neck,6 of whom were misdiagnosed as thyroid abscess and suffered surgery.7 patients represented masses in left anterior neck.Ultrasound showed all patients with diffuse en-larged thyroid gland with uneven mass and separated liquid dark space or infection in deep neck soft tissue,and no CPSF was identi-fied.The subsequent esophageal barium meal confirmed the fistula in 8 patients,and other patients underwent further CT scan with image post-processing.CT showed clear fistula in 4,suspicious fistula in 7 and no fistula in 4,All fistulas were confirmed by the pa-thology.Conclusion The combination of ultrasound,esophagogram and CT with image post-processing can improve the diagnostic sensitivity and accuracy of CPSF.

Objective To establish and clinically evaluate a method to adjust tube current(mA)individually for obtaining images with consistent noise and optimized radiation dose in 64-slice spiral helical CT coronary angiography.Methods (1)80 patients,as a control group,were underwent CT coronary angiography(CTCA)using 64-muhislice spiral helical CT with fixed mA(650 mA).Two radiologists first assessed image quality of the fixed mA group by scoring from 1 to 5.A minimal dose requirement for meeting clinical diagnosis with the desired noise level(standard deviation SD0)were decided.By analyzing the images of the control group,we also established correlation between the image noises of timing bolus(TB)scans and cardiac(CA)scans and set up a formula to predict the required mA value for obtaining the desired cardiac image noise for individual patient.(2)Subsequently,another group of 80 patients(study group)wero scanned with individually adjusted mA using the established formula and the practicability of this method was then evaluated.The independent sample t test was used to compare the values of the two groups.Results (1)The noise of TB and CTCA scans was linearly correlated with r2=0.994. (2)A cardiac image noise level of 28 HU was found to be adequate for clinical diagnostic purpose based on the image quality analysis.(3)The average noise for the acquired cardiac images was found to be 28.97 HU for the study group with individually adapted mA using the established formula.The standard deviation of the image noisein study group was 1.93,which was much smaller than 5.14 in the fixed mA group,but the average image scores for the study group(4.27±0.68)and fixed group mA(4.03 4-0.93)were not statistically different.(4)In the study group,63 out of 80 patients required tube currents below the standard 650 mA,yielding an average CTDIvol of58.32 mGy,which was about 32.1%dose reduction than that of fixed mA(85.94 mGy).The lowest CTDIvol was 19.27 mGy with 160 mA which was 22.4%of the average CTDIvol in control group.Conclusion Adjusting mA individually based on timing bolus scan noise analysis is an accurate and practical method to obtain consistent image quality for different cardiac pailents and to minimize the radiation dose for individuals compared to the fixed mA.

Objective To analyze the application value of digital radiography (DR) on healthy population.Methods 1449 cases of health examination on chest by DR were retrospectively studied,the physical examination results were analyzed.Results The medical examination of positive rate was 4.9％.The positive rate of women was higher than men ( x2 =11.493,P =0.001 ).the top 5 detection rate of diseases were lung old lesions,pneumonia,suspicious tumor,thickening and adhesion of pleural,senile pulmonary.Conclusion The DR examination was selected according to symptoms,medical history of participate in the examination,the check frequency was selected according to age.

25 is also an important impact factor among various components.

Objective To control the image quality and to optimize the scan protocols of 64 multi-slice CT coronary imaging by analyzing factors that influence the image quality.Methods Seventy-eight patients with known or suspected CAD underwent CT coronary angiography using 64 multi-slice CT.The image quality in those cases was analyzed retrospectively to derive the optimized scan protocols.The application value of the override function was discussed.The dependency of cardiac reconstruction algorithms and corresponding image quality on patient heart rates was analyzed.In addition,the relationship between heart rate and the contrast-enhancement effect was studied.Results(1)Correct use of override function could improve the quality of cardiac images.(2)For patients with heart rates below 70 beats per minute,the image quality of single-segment reconstruction was satisfactory.For patients with heart rates between 70 and 79 beats per minute,the scores of images reconstructed with two-segments were better than that of single-segment reconstruction.(3)In the group with averaged heart rate of 60.7 beats per minute,the forecast contrast quantity of 70 ml was judged insufficient in 65.7%(23/35)cases;while for the group with averaged heart of 71.1 beats per minute,52.9%(18/34)cases were enhanced well.Conclusion The use of override function,correct segment mode and appropriate contrast quantity could be selected according to the heart rate,which could improve the image quality and reliability.

The clinical manifestations and CT findings of 26 patients,who were full-time cooks working in small restaurants,were analyzed retrospectively.The main clinical manifestations were chest congestion,shortness of breath,chest pain,cough and hemoptysis.Lung CT scanning revealed lung carcinoma in 1 case,pulmonary nodules in 16 cases including 2 cancerous nodules confirmed in the followup review,puhnonary bulla in 6 cases,emphysema in 4 cases,fibro-proliferative lesions in 8 cases,interstitial pneumonia in 4 cases and fungal ball in 1 case.Among 26 patients,12 had two or more concurrent intrapulmonary lesions.The results suggest that long-term exposure to cooking oil fume may lead to a series of pulmonary pathological changes,and attention should be paid to the occupational hazards of cooks.

Purpose To analyze the image quality of brain CT with 256-slice wide detector axial scanning mode,routine axial scanning mode and spiral scanning mode,and to provide a more effective brain CT examination method for patients.Materials and Methods The prospective study was conducted on 90 patients accepting routine brain CT examination,and they were randomly divided into three groups.CT examination with 160 mm axial scanning mode,40 mm axial scanning mode and 40 mm spiral scanning mode were respectively conducted using GE Revolution CT.The scanning condition was adjusted to remain constant radiation dose,and then the image quality was analyzed.CT attenuation of gray and white matter,contrast-to-noise ratio (CNR) of white-gray matter and image noise of the three scanning modes were compared.Subjective scoring on image quality of the three scanning modes was also performed.Results On body lateral cerebral ventricle level,there were no significant difference in CT attenuation of gray and white matter and CNR (P＞0.05).On centrum semiovale level,the CT attenuation of gray matter [(31.71 ± 1.82) HU],white matter [(22.97± 1.50) HU] and CNR 2.05±0.42 of 160 mm axial scanning mode was significantly different from the other two scanning modes (F=26.74,47.16 and 3.85,P＜0.05).On centmm semiovale level,image noise of 160 mm axial scanning mode was lower than the other two kinds of scanning methods (F=6.31,P＜0.05),in the basal ganglia and posterior fossa there were no statistically significant differences in the image noise between the three scanning modes (P＞0.05).The subjective score of the three scanning modes all met the diagnostic requirements,and there was no significant difference (P＞0.05).The effective dose and scanning time of 160 mm axial scanning mode was lower than those of the other two scanning modes,and the X-ray utilization was higher.Conclusion 160 mm wide detector axial scanning mode is more suitable for brain CT scan,and it can be used as the preferred scanning mode in the emergency and among non-cooperative patients.

To study the dynamic changes of CT perfusion parameters during the first 12 h in the embolic cerebral ischemia models. Local cerebral ischemia model were established in 7 New Zealand white rabbits. All CT scans were performed with a GE Lightspeed 16 multislice CT. Following the baseline scan, further CT perfusion scans were performed at the same locations 20 min, 1-6 h and 8, 10 and 12 h after the embolus delivery. Maps of all parameters were obtained by CT perfusion software at each time point. The brains, taken 12 h after the scan, were sliced corresponding to the positions of the CT slices and stained by 2,3,5-triphenyltetrazolium chloride (TTC). On the basis of the TTC results, the ischemic sides were divided into 3 regions: core, penumbra and the relatively normal region. The changes of all parameters were then divided into 3 stages. In the first two hours (the first stage), the CBV dropped more remarkably in the core than in the penumbra but rose slightly in the relatively normal region while the CBF decreased and MTT, TTP extended in all regions to varying degrees. In the 2nd-5th h (the second stage), all the parameters fluctuated slightly around a certain level. In the 5th-12th h (the third stage), the CBV and CBF dropped, and MTT and TTP were prolonged or shortened slightly in the core and penumbra though much notably in the former while the CBV, CBF rose and MTT, TTP were shortened remarkably in the relatively normal region. We experimentally demonstrated that the location and extent of cerebral ischemia could be accurately assessed by CT perfusion imaging. The pathophysiology of the ischemia could be reflected by the CT perfusion to varying degrees.
Blood Flow Velocity ; Brain Ischemia/physiopathology ; Brain Ischemia/*radiography ; Cerebrovascular Circulation ; Stroke/physiopathology ; Tomography, X-Ray Computed