Objective To study the relationship between the enhancement of renal cortex and medulla during the conventional CT scans with and without contrast enhancement and the renal glornerular filtration rate (GFR). Methods Thirty five cases with unilateral posternal obstructive hydronephrosis According to GFR, the 70 kidneys were divided into 4 groups: normal, slightly impaired, moderately impaired and severely impaired. In the cortical phase of enhanced CT scan, the enhancing intensity of the renal cortex and medullar was measured and following measures were calculated: CTce - CTcp, CTmc -CTmp,ratio of enhancement of affected and unaffected renal cortex and medullar, and the ratio of those of each case: CTac/CTnc, CTam/CTum, CTac/CTam, CTnc/CTnm, (CTac/CTam) / (CTuc/CTum). The differences of these measures in different groups were analyzed with one-way ANOVA and their correlation with GFR was studied with Pearson test. The best indicator to reflect enhancement of renal cortex was selected from these measures, and all the kidneys were divided into 4 groups accordingly: strong, less strong, medium and weak. Then its consistency with GFR groups were calculated. Result (1) The differences of CTce - CTcp ( 154. 98 ± 28. 70 ), ( 122.67 ± 39. 32 ), ( 81.30 ± 32.94 ) and ( 57.60 ±23.49) HU respectively, CTac/CTuc 0. 97 ±0. 09, 0. 79 ±0. 18, 0. 64 ±0. 24 and 0. 51 ±0. 13 respectively,CTam/CTum 0. 98 ±0. 26, 0. 89 ±0. 18, 0. 86 ±0. 31 and 0. 75 ±0. 28 respectively, CTam/CTum 2. 76 ±0. 35,2. 35 ± 0. 79, 1. 83 ± 0. 68 and 1.73 ± 0. 28 respectively, CTac/CTam and ( CTac/CTam)/( CTuc/CTum) 1.00 ±0. 28,0. 89 ±0. 34, 0. 75 ±0. 17 and 0. 69 ±0. 14 respectively of different GFR groups were evident( P < 0. 05 ) . ( 2 ) Positive correlation was found between GFR and CTce-CTcp ( r = 0. 887, P <0. 01 ), CTac/CTuc ( r = 0. 872, P < 0. 01 ), CTam/CTum ( r = 0. 504, P < 0. 01 ), CTac/CTam ( r =0. 772, P < 0. 01 ), (CTac/CTam) / (CTuc/CTum) ( r = 0. 663, P < 0. 01 ). ( 3 ) Selecting CTac/CTam to reflect enhancement of renal cortex, the diseased kidneys can be divided into groups of strong ( CTac/CTam ≥2. 60); less strong (2. 20 ≤CTac/CTam <2. 60); medium ( 1.80 ≤CTac/CTam <2. 20); and weak ( CTac/CTam < 1. 80). The consistency with GFR grouping was 80. 0%. Conclusions There is significant correlation between renal cortex-related indicators and GFR, especially CTac/CTam, which can be used as the indicator of renal function in patients with unilateral or bilateral postrenal obstructive hydronephrosis. The conventional contrast enhanced CT scan can be taken as a semi-quantitative method of GFR measuring with relative low X-ray dosage compared with CT perfusion.

Objective To determine and evaluate the method of localization of anal verge by mutislice spiral CT. To provide an imaging reference for operative guidance of low-rectal cancer. Methods Forty eight consecutive adult patients suspected of abnormalities other than rectal disease were evaluated with abdominal and pelvic CT scans since August, 2009. They were divided into two groups based on sex and age. There were 23 men and 25 women. The ages of young group were 28 to 50 years and the average age was 41 years. The ages of elderly group were 52 to 81 years and the average age was 64 years. A small cotton ball dipped with contrast media was put at the anal verge as a marker and CT scans were performed with 64-slice spiral CT scanner. The distances between the cotton balls and the lower margin of the pubis combination (La), the lower margin of the 5th sacral vertebra (Lb), the inferior aperture of minor pelvis(Lc) and the lower margin of the basement of external anal sphincter (Ld) were measured on the midsagittal images obtained by MPR. The averages, the standard deviations(s), the 95% and 80% confidence intervals of La, Lb, Lc and Ld were calculated. We took the intervals of ± 1.96 s or ± 1.28 s ＜ 5 mm as the standard of meeting the clinical requirement. The distances meeting the clinical requirement between different sex groups or age groups were compared with t test. Results The Ld was (9.8 ± 1.2) mm, ofwhich intervals of ± 1.96 s and ± 1.28 s were 4. 8 mm and 3.0 mm respectively, meeting the clinical need.This distance was also measured conveniently. There were no significant differences ( P ＞ 0.05 ) between two different sex groups [ male group, ( 10.0 ± 1.2) mm], female group, (9.6 ± 1.2) mm and between two age groups [ young group, (9.6 ± 1.2) mm, elderly group, ( 9.9 ± 1.3 ) mm ]. Conclusions The lower margin of the basement of external anal sphincter was a useful anatomic lanmark for localizing the anal verge,and could be definitely identified on the middle sagittal pelvic CT image. The distance between the structure and anal verge is constant enough and can be used in measuring distance from low rectal lesion to the anal verge.

Objective To study the relationship between polyps of middle meatus and the position of the inferior border of the middle concha related to the semilunar hiatus, and to evaluate the diagnostic value of coronal CT scan of the nasal cavity after ephedrine spray by means of comparison of CT images and clinical findings Methods The coronal CT studys of 102 cases clinically suspected as sinusitis and/or nasal polyps were included in this study 1% ephedrine was sprayed in nasal cavity of the patients before CT study and the patient were asked to take supine position with head over extended over 5 minutes Axial and coronal CT scan was taken with supine position, 2 mm slice thickness and high resolution reconstruction Observation was focused on contraction of the nasal mucosa and soft tissue mass of the middle meatus (polyps) The middle concha was divided into 3 types according the position of its inferior border related to the semilunar hiatus: superior hiatus type (the inferior border of the middle concha superior to the semilunar hiatus), hiatus type (the inferior edge of the middle concha at the level of the semilunar hiatus), inferior hiatus type (the inferior edge of the middle concha inferior to the semilunar hiatus) Statistic comparing the occurrence of the middle meatus polyps with different middle conchas type and measuring the length of the middle conchas of inferior hiatus type from the level of the semilunar hiatus to the inferior border were performad Results Good and better contraction of the nasal mucosa with clear manifestation of the lesion was seen in 98 of 102 cases Nasal polyps of middle meatus were diagnosed in 71 sides of nasal cavities of 47 cases and confirmed surgically and/or clinically 39 superior hiatus and hiatus middle conchas were found ipsilateral to the polyps (54 9%) Of 204 sides of 102 cases, superior hiatus type middle conchas was found in 18 sides of nasal cavity with middle meatus polyps in 11 sides (61 1%); hiatus type in 38 sides with middle meatus polys in 28 sides (73 7%); and inferior hiatus type in 148 sides with middle meatus polys in 32 sides (21 6%) The difference was markedly significant statistically Conclusion Coronal CT scan after ephedrine spray into the nasal cavity can depict the mass in the nasal cavity better, especially nasal polyps with swollen mucosa The method is simple and easy to perform The poorly developed middle concha and the exposed middle meatus may be one of the causes of polyps of middle meatus It clues on that the middle concha should be preserved as much as possible during the endoscopic sinus surgery, opening the ethmoidal infundibulum and bullas, to decrease post operative recurrence of middle meatus polyps

Objective To study the relationship between the renal cortical thickness and age,and to establish the range of the normal renal cortex thickness by using CT measurement in different age groups so as to obtain a best age-related and practicable method for clinical measurement. Methods (1) the accuracy of measuring renal cortical thickness by CT was evaluated; 18 kidneys resected due to renal neoplasm were studied and the cortical thickness of the normal part of these specimens was assessed. The difference between the renal cortical thickness of specimens and preoperative measurements of renal cortex of the same patient by contrast enhanced CT was analyzed statistically. (2) 120 patients without history of renal disease or long term usage of potentially renal toxic drugs or history of hypertention were examined by CT with indication(s) other than renal disease. All the patients were divided into 20-40, 41-60, and 61-80 year-old groups. The renal cortical and parenchymal thickness and renal size were measured in three CT sections. The difference of the measurements among the three groups and their relationship to age was analyzed statistically. Results There was no significant difference between the renal cortical thickness measured by enhanced spiral CT and measured in renal specimens(t =0. 80,P =0. 43). The renal cortical thickness in three groups was 0. 73 cm, 0. 65 cm, and 0. 53 cm, respectively, and the differences among the three groups were significant ( F = 93.430, P 0. 05). Conclusion The measurement of the renal cortical thickness with enhanced spiral CT was reliable and was a sensitive method in investigating the morphologic changes of the kidney. The renal cortical thickness of normal kidney diminishes with age, but the change of the ratio of thickness of renal cortex to renal parenchyma with age was not significant.

0.5). Conclusion To some extent, the cup sign and split sign on CT reflect the biologic character of AMLs, and the signs are helpful in making the specific diagnosis of AML combined with other imaging manifestations.

Objective To investigate enhanced CT scanning in differentiation of solitary pulmonary nodule and relationship between the degree and pattern of enhancement and vascularity. Methods 11 patients with surgically confirmed pulmonary carcinoma and 13 patients with inflammatory nodules and 6 patients with tuberculoma were studied with plain chest CT sean and enhanced scanning after injection of 100 ml iodinated contrast medium to observe the enhancement degree and pattern of the lesion before the surgery. Vaseularity of specimens of 11 carcinoma and 13 inflammatory nodules and 6 tuberculoma were examined pathologically and correlated with degree of enhancement. Results The pulmonary carcinoma and inflammatory nodules showed a significantly higher degree of enhancement than tuberculoma. But the carcinoma and the inflammation showed no differences in degree and pattern of enhancement. The degree of enhancement was positively correlated with the number of blood vessles. The vascularity of carcinoma and inflammation was far richer than that of tuberculoma. Conclusion The results suggested that the enhanced CT scanning are distinctively different between carcinoma and tuberculoma,whereas little different between carcinoma and inflammation. Vascularity of the lesion plays an important role in the manifestation of enhancement.

ObjectiveTo derive and evaluate the formula of exactly calculating the contrast dosage used during pulmonary CT angiography ( CTPA ). Methods Time density curves in 27 patients who underwent CTPA were collected and analyzed,the formula for calculating contrast dosage during CTPA was derived.68 patients suspected of pulmonary embolism ( PE ) clinically but no PE on CTPA were divided randomly into group A,with bolus tracing technique ( n =26 ),and group B,with small dose injection contrast test (SDCT) (n =42).The CT values of the right main pulmonary artery (RMPA),right upper pulmonary vein ( RUPV),right posterior basal PA,right lower PV (RLPV) and the aorta were calculated.The total contrast dosage and the hard beam artifact in the SVC were compared between the two groups.Student's t test,Chi-square test and Mann-Whitney U test were used.ResultsThe ratio of the time from starting injection to enhancement peak of caudal end of SVC and the time to enhancement peak of the main pulmonary trunk was 0.65 ±0.09 (about 2/3),the formula for contrast dosage calculation was derived as (DTs/3 + STs/2) FR ml/s.The CT values of RMPA and RLPA between the two groups[ (301 ±117),(329 ± 122) and (283 ±95),(277 ±98) HU respectively] were not significantly different (t =1.060,P =0.292 ;t =2.056,P =0.044),but the differences of CT values in the paired PA and PV between the two groups (median were 22.5,58.0 and 170.5,166.5 HU respectively ) were significant (U =292,P =0.001 and U =325,P =0.005),contrast artifact of the SVC (grade 1-3) in group B ( n =34,7,1 respectively) was significantly less than in group A (n =11,10,5 respectively,x2 =10.714,P =0.002),the contrast dosage injected in group A was ( 87.6 ± 7.3 ) ml,and in group B was ( 40.0 ±5.4) ml (P ＜0.01 ).ConclusionCTPA with SDCT technique is superior to that with conventional bolus tracing technique regarding contrast dosage and contrast artifact in the SVC.

Objective To investigate the dynamic enhanced CT scanning in differentiation of small lung cancer.Methods 20 patients with pathologically confirmed small lung cancer,and 6 patients with inflammatory nodules,5 patients with tuberculoma were studied with plain chest CT scan and dynamic enhanced (the delay time of scans was 30 s,1,3,5,7 min after injection)before surgery.Then the enhancement degree of the lesions was recorded in different time lag.The time-attenuation curves of different diseases were drawn.Results Tuberculoma showed a significantly lower degree of enhancement than the pulmonary carcinoma and inflammatory nodules,it showed a lower and flat line.The carcinoma and the inflammation showed no differences in degree of enhancement.But the peaks of the tow curves appeared to be different in various time of delay,tumor reached its peak in 1～3 minute after injection of contrast medium which dropped behind the inflammatory.Conclusion The results suggested that from the time-attenuation curve we could make the different diagnosis between small lung lesions.

0.70). The detection rate of 5 mm nodules declined when large pitch was used. Conclusion The detection rates of 10 mm and 5 mm nodules had no difference between low-dose CT and conventional-dose CT. As the pitch augmented, the detection rate for the nodules declined.

Objective To evaluate the usefulness of extrapleural locating method in CT-guidod transthoracic pulmonary biopsy to prevent or reduce the size of peumothorax.Methods One hundred and fifteen cases of CT-gnided transthoracic pulmonary biopsy with the pulmonary lesions not in direct contact with the pleura were selected.Of 115 cases,46 were performed with extrapleural locating method (EPL) and 69 cases with lesion edge locating method (LEL).Taking the maximum distance between the partial and visceral pleura (MPVD) measured on the CT image after the procedure as the index of the volume of pneumothorax.The incidence and volume of pneumothorax of both groups were compared and statistically analysed with R ×C Chi-Square test.The retention time of the biopsy needle in the lung parenchyma of the two group was documented and the average time was calculated in each group.Results The incidence of pneumothorax was 45.7% (21/46),median 0.4 cm with EPL group,and 66.7% (46/69) and median 0.3cm with LEL group.When the distance between the lesion and pleura was equal or smaller than 2 cm (≤2cm),the incidence of pneumothorax was 39.4% (13/33) with EPL group and 73.2% (30/41) with LEL group,and the difference of incidence and volume of the pneumothorax between two groups was statistically signifieant(X2 =9.981,P =0.019).When the distance was larger than 2 cm( >2 cm),the incidence and volume of pneumothorax between two groups were not significant statistically.The average retention time of the biopsy needle in the lung parenchyma was (7.2±1.8)s with EPL group and (58.3±11.6) s with LEL group.Conclusion The extrapleural locating method can reduce effectively the retention time of the biopsy needle in the lung parenchyma and the incidence and volume of pneumothorax in CT-gnided transthoracic pulmonary biopsy.