[en] Objective: To quantify the values of fractional anisotropy (FA) and eigenvalues (k) using diffusion tensor imaging in the putamen and globus pallidus respectively, and to investigate their relationship with aging. Methods: Sixty nine normal volunteers (38 men and 31 women; age range, 20- 80 years; mean age, 42 years) were studied. All the participants were divided into three groups (group I: ≤30 years, group II: 31-50 years, group III: >50 years). The values of ADC, FA, λ₁, λ₂ and λ₃ in putamen and globus pallidus were calculated after diffusion tensor scanning, and then analyzed the differences between the two tissues. The differences of ADC, FA, λ₁, λ₂ and λ₃ values among age groups were analyzed by using analysis of variance (ANOVA), and their relationship with age were accessed by using Pearson correlation. Results: Between the correspondent age groups, the ADC value was higher in the putamen [(6.68 ± 0.40) x 10^-4, (6.47 ± 0.36) x 10^-4, (6.44 ± 0.34) x 10^-4 mm²/s] than that in the golbus pallidus [(6.13 ± 0.50) x 10^-4, (6.05 ± 0.33) x 10^-4, (6.05 ± 0.52) x 10^-4 mm²/s], and the value of FA in the putamcn (0.20 ± 0.03, 0.23 ± 0.03, 0.25 ± 0.03) was lower than that in the globus pallidus (0.35 ± 0.03, 0.36 ± 0.03, 0.37 ± 0.04). ANOVA analysis of the FA value among age groups revealed there were significant differences in the putamen (F=10.082, P=0.000), and the same analysis of eigenvalue k₃ in the putamen also showed significant differences (F=5.675, P=0.005). The FA value in the putamen was significantly elevated with aging (r=0.555, P<0.01), and eigenvalue k3 in the putamen showed age-related decline (r=-0.440, P<0.01). ANOVA and Pearson correlation analysis of all parameters in the globus pallidus showed no significant differences. Conclusion: The phenomenon of age-related elevation of the FA value lied in the putamen, not in the whole lenticular nuclei, and λ₃ in the putamen showed age-related decline. (authors)

[en] Objective: The purpose of this study was to investigate the effect of age on the iron concentration of the human brain. Methods: The brain iron level was evaluated in vivo in 78 healthy adult volunteers using a noninvasive magnetic resonance method termed susceptibility weighted imaging. The subjects were divided intothree groups due to different ages: young (22-35 years old, n=27), middle- aged (36-55 years old, n=35), and aged (56-78 years old, n=16). The phase values were measured on the corrected phase images in the globus pallidus, putamen, caudate, substantia nigra, red nucleus, thalamus and frontal white matter. The phase values of those regions measured from the subjects over than 30 years old were correlated with published values of brain iron concentration in normal adults to check the validity of the data. Then, the phase values of the three groups were tested for significant age-related differences using one-way ANOVA, followed by post hoc testing using least significant difference (LSD) procedure. Regression analysis was used to further examine age-related effects revealed by group comparisons, and to estimate the rates of age-related changes. Results: A strong negative correlation was found between the phase values and the published values of the brain iron concentration (r=-0.796, P= 0.032), which indicated that the higher the iron deposition level, the greater the negative phase values. In the putamen (F=20.115, P<0.01) and frontal white matter (F=3.536, P=0.034), significant differences were detected in the phase values of the three age groups. Linear regression analysis showed that phase values of the putamen, frontal white matter, and red nucleus decreased with age (The regression coefficients were -0.001, -0.001, and < -0.001 respectively, and the P value were all < 0.05), which indicated that the iron concentration of those brain structures increased with age. No significant age- related changes of the iron concentration were found in the globus pallidus, caudate, substantia nigra, and thalamus. Conclusions: These findings extended our knowledge of the patterns of the brain iron accumulation in normal aging. Such information is necessary to understand disease-related changes that involve the brain iron deposition. (authors)

[en] Objective: To investigate the relationship between dynamic contrast-enhanced MRI-derived patterns and histological microvessel density (MVD) counts in pulmonary carcinoma. Methods: Forty-eight patients with pathologic analysis-proved pulmonary carcinoma underwent dynamic contrast-enhanced MR imaging before operation. Dynamic contrast-enhanced MRI-derived parameters [steepest slope, SS; peak height, PH; and the change in signal intensity in percent at 1(E₁), 2(E₂), and 4(E₄) minutes] were calculated based on time-signal intensity curves. The statistical correlation tests were used to determine the strength of the relationship between enhancement parameters and microvessel density counts. Results: For 48 tumors, the mean value of microvessel density was 56.07±22.61. Squamous cell carcinoma had a mean count of 44.41±16.28 vessels (n=26), whereas adenocarcinoma had significantly higher counts (69.86±21.47 vessels, n=22) than squamous cell carcinoma (t=4.666, P<0.01). There were statistically significant correlations between SS, PH, E₁, E₂, E₄, and MVD, respectively. The highest correlation, however, was between the SS and MVD (r=0.874, P<0.01). Conclusion: Tumor microvessel density is the pathophysiological basis of the enhancement patterns of dynamic contrast-enhanced MRI in pulmonary carcinoma. Enhancement patterns of dynamic contrast-enhanced MRI have strong positive correlations with angiogenesis in pulmonary carcinoma

[en] Objective: To evaluate solitary pulmonary nodules (SPNs) using quantitative dynamic contrast enhanced functional computed tomography (CT), and to illustrate its clinical efficacy in differential diagnosis between benign and malignant pulmonary nodules. Methods: Eighty patients with non-calcified SPNs (diameter, 5-30 mm) were studied with dynamic contrast enhanced CT. Patterns of time-density curve (T-DC) were assessed. The precontrast density, peak height in density (PH: the maximum value of the T-DC), and S/A ratio (the ratio of the PH of SPN over aorta) were recorded. Enhancement patterns of SPNs were also recorded. The perfusion of SPNs was calculated. Results: Malignant, benign, and inflammatory nodules showed quite different patterns in T-DC. PH and S/A ratio of the malignant and inflammatory nodules were significantly higher than those of the benign nodules (P<0.0001; P<0.0001; χ²=32.62, P<0.0001; χ²=15.46, P<0.0001), while no statistical difference of the PH or S/A ratio was found between the malignant and inflammatory nodules (P=0.96; χ²=0.35, P=0.55). Precontrast density of the inflammatory nodules was lower than that of the malignant nodules (P<0.05). Both the malignant and inflammatory nodules showed significantly higher perfusions than that the benign nodules (P<0.001; P<0.01). However, the difference of the perfusion between the malignant nodules and inflammatory nodules was not significant (P=0.63). Conclusion: Dynamic contrast enhanced functional CT can provide quantitative information about blood flow patterns of SPNs and proved to be an alternate non-invasive option in the evaluation and management of solitary pulmonary nodules

[en] Objective: To investigate the correlations of lymphatic involvement and perfusion patterns of pulmonary carcinoma derived by dynamic contrast-enhanced MRI as well as the histological microvessel density (MVD)of the tumor's. Methods: Fifty-eight patients with pulmonary carcinoma were classified into two group according to the pathologic reports:tumors with mediastinum lymphatic involvement and tumors without mediastinum lymphatic involvement. All cases were underwent dynamic contrast- enhanced MR scanning. The parameters of dynamic contrast-enhanced MRI were calculated based on time-signal intensity curves. The correlations of lymphatic involvement and MRI parameters as well as tumor's MVD were analyzed. Results: Tumors with mediastinum lymphatic involvement (n=35) had significantly higher values of both MVD and SS than those without mediastinum lymphatic involvement (n=23) (MVD72.37±13.74 vs 42.61±16.18;SS=5.05±1.16 vs 2.57±l.09)(t=7.521;t=8.157,P<0.01). With the ROC curve analysis, if the SS 3.8 or MVD 63 was taken as s a threshold to predict lymphatic involvement, high sensitivity of SS(85.7% ,30 of 35), MVD (74.3%, 26 of 35) and high overall accuracy of SS (87.9, 51 of 58), MVD (82.8%, 48 of 58) could be reached, respectively. The area zone under the ROC curve of SS (AZ_SS) tended to have higher value than that of MVD (AZ_MVD) (0.958 versus 0.920), however, the difference between the values of AZ_SS and AZ_MVD was not significant (P=0.09). Conclusion: SS and MVD had good correlation with lymphatic involvement of pulmonary carcinoma, and could be used to predict lymphatic involvement. (authors)

[en] Objective: To investigate the role of dynamic contrast-enhanced computed tomography (DCE-CT) in the evaluation of tumor angiogenesis in patients with lung carcinoma. Methods: 34 patients with pathology-proved pulmonary, carcinoma underwent DCE-CT scan before operation. The functional imaging parameters: peak height(PH), the time of peak height (Tp), the ratio of PH of the mass to aorta (M/A), perfusion, the relative blood volume (rBV) and permeability (Pm) were calculated and correlated with the microvessel density (MVD) of the carcinoma. The functional imaging parameters MVD and the lymph node involvement between VEGF positive group and VEGF negative group were analyzed. Results: The Perfusion, PH, M/A and rBV correlated positively with MVD (r=0.76, 0.67, 0.70, 0.65 respectively; P<0.0001), and no significant correlation was found between Pm and MVD (r=0.30, P> 0.05). The functional imaging parameters and MVD of VEGF positive group were higher than those of VEGF negative group (P<0.05) and the difference of lymph node involvement between two groups was significant (χ²=9.409, P<0.05). Conclusion: DCE-CT functional imaging technique provides general information of lung carcinoma angiogenesis and alternates non-invasive option for evaluation of tumor angiogenesis in patients with lung carcinoma. (authors)

[en] Objective: To evaluate the diagnostic efficacy of contrast enhanced dynamic MRI in differentiating benign from malignant solitary pulmonary nodules (SPNs). Methods: A prospective study was undertaken in forty-four patients with SPNs using contrast enhanced dynamic MRI. Patterns of Time-Signal Intensity Curve (T-SI Curve) were assessed. Steepest Slope (SS), Peak Height (PH) and the change rates in signal intensity at the first (E₁), second (E₂), and fourth (E₄) minute of T-SI curve were calculated. Results: Malignant nodules and inflammatory nodules showed higher SS [(4.44 +- 1.40)%/s, (3.99 +- 0.71)%/s, (0.86 +- 0.37)%/s, P<0.001] values than that of the tuberculomas and bronchogenic cysts, respectively. Inflammatory nodules showed higher E₄ values and later enhancement than what malignant nodules showed [(120.02 +- 6.95)%, (67.03 +- 18.04)%, P<0.001]. Conclusion: Contrast enhanced dynamic MR imaging provides quantitative information of SPNs' blood flow and is proved to be an applicable diagnostic methods for differentiating SPNs

[en] Objective: To investigate the optimal R-R phase of retrospectively electrocardiographically (ECG)-gated image reconstruction for multi-slice spiral CT (MSCT) coronary reconstruction and it's clinical application. Methods: A total of 20 patients with known or suspected coronary artery disease (CAD) were detected with retrospectively ECG-gated MSCT (4 x 1.3 mm cross-section, 500-ms rotation, pitch 0.375) during a single breath hold. Tomographic source images were reconstructed at the starting points of 37.5%, 50.0%, 62.5%, and 75.0% R-R intervals, followed by volume rendering (VR) and virtual vascular endoscopy (VVE) for reconstruction of coronary artery. The quality of images reconstructed with different R-R phases was analyzed in terms of artifacts and visibility. Selective coronary angiography (SCA) was used for reference. Results: The left anterior descending artery, the left circumflex artery, and the right coronary artery were all best visualized at 50.0% and 62.5% R-R phases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the detection of ≥50% stenosis with the optimal R-R phase imagines of MSCT were 91.7%, 83.3%, 28.2%, 99.3%, and 83.9%, respectively. Conclusion: The optimal R-R phase of retrospectively ECG-gated reconstruction images can decrease the artifacts of cardiac motion and improve the reconstructive image quality of coronary arteries. With high sensitivity and negative predictive value, MSCT coronary reconstruction is considered as a good screening test before SCA

[en] Objective: To optimize the scheme and process of chest CT scanning and control the dose level to the examined individuals by establishing the diagnostic reference level (DRL) and warning dose value from chest CT examinations in our hospital. Methods: The medical records for 205511 examined individuals, who had undergone chest CT scans in the Second Affiliated Hospital of Zhejiang University Medical College from January 1, 2018 to December 31, 2019, were reviewed consecutively. For the two-year examination periods, these examined individuals were divided into two groups, one for 2018 totalling 90 507 and another for 2019 with a total of 115004. The mean value of doses from chest CT scans in 2018 was set as the DRL for the hospital, with the 75 th and 25 th percentiles as the upper and lower limits of diagnostic reference range (DRR) and the 97.5 th percentiles as the warning dose values. The doses above the upper limit of DRR were considered to be relatively-high whereas the ones exceeding the warning dose value to be over-high. Based on the analysis of the over high dose in 2018, the scanning scheme and inspection process of the chest CT scans were improved in 2019. The number of examinations were estimated for the 2018 period for chest plain CT scans, chest enhancement CT scans, lung cancer screening low-dose CT scans, and relatively-high and over-high dose CT scans, as well as the single scanning doses to the examined in the two groups. The number of examinations resulting in high dose to the examined due to different reasons before and after the improvement were studied. The various parameters on the examined in the two groups were compared statistically. Results: After the improvement, the average dose from chest plain CT scans decreased by 8.67 %, with the statistically significant difference as compared with before improvement (t = 55.71, P < 0.05). The average dose from low-dose chest CT scans fell by 20.13% with statistically significant difference (t = 81.99, P < 0.05). The fraction of the examinations with slightly-high doses arising from chest plain CT scans and low dose chest CT scans dropped by 3.66% and 17.15%, respectively. The fraction of the examinations with slightly-high dose from chest enhanced CT increased by 1.7%. The fraction of the examinations with over-high dose from chest plain CT scans, enhanced CT scans and low-dose CT scans decreased by 0.55%, 1.06% and 1.74%, respectively. After improvement, the optimized fraction of the examinations with over-high dose, dropped by 4.72%, 31.49% and 19.18% respectively. Conclusions: The establishment of the DRL and the warming dose value of for chest CT examinations in our hospital is helpful to find out the cause of high dose scanning, promote the optimization of dose, reduce the average dose to the examinees, and avoid using excessive dose during scanning. (authors)

[en] Objective: To investigate the differences of the underlying neural basis of language processing between normal subjects and aphasics, and to study the feasibility for functional magnetic resonance imaging (fMRI) in examining the cortical language activation in clinical aphasics. Methods: fMRI was used to map language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed word generation task during fMRI scanning, which measured the signal changes associated with regional neural activity induced by the task. These signal changes were processed to statistically generate the activation map that represented the language area. Results: In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions in normal group. In the patient group, however, no activation was showed in the left inferior frontal gyrus whether or not the patient had lesion in the left frontal lobe. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusion: The remote effect of focal lesion and functional redistribution or reorganization was found in aphasic patients. fMRI was useful in evaluating the language function in aphasic patients. (authors)