Correlation between quantitative perfusion histogram parameters of Dynamic Contrast-Enhanced MRI and tumor tis-sue microvessel density in patients with lung cancer / 中华胸心血管外科杂志

Objective To investigate the correlation between quantitative perfusion histogram parameters of DCE-MRI and tumor tissue microvessel density(MVD) in patients with lung cancer.Methods 30 patients with lung cancer confirmed by pathology who underwent preoperative DCE-MRI were enrolled in this retrospective study .Quantitative perfusion histogram pa-rameters( including median, mean, skewness, kurtosis, energy, entropy) were measured for each patient using Exchange mo-dle.Using the Immunohistochemical method to detect the expression of CD34 in tumor tissue, and counting the number of mi-crovessels under microscope.SPSS 19.0 was used to carry out statistical analysis.The correlation between MVD and quantita-tive perfusion histogram parameters of DCE-MRI measured by exchange model was evaluated by Pearson linear correlation anal-ysis.Results There was no significant difference in MVD and each quantitative perfusion histogram parameters between the three different pathological groups of lung cancer(P >0.05).Ktrans perfusion histogram parameters(mean, 25％, 50％, 50％, 75％, 90％, 95％), Kep perfusion histogram parameters(entropy, 10％, 25％, 50％, 75％, 90％), Fp perfusion histogram parameters( mean, 25％, 50％, 75％, 90％, 95％) and Vp perfusion histograms parameters ( entropy, 75％, 90％, 95％ ) were positively correlated with MVD(P<0.05).Ktrans perfusion histogram parameters(energy) and Vp perfu-sion histogram parameters(skewness, kurtosis, energy) were negatively correlated with MVD(P<0.05).There was no signifi-cant correlation between Ve perfusion histogram parameters and MVD(P>0.05).Conclusion There was a certain correla-tion between the perfusion histogram parameters of DCE-MRI and MVD,suggesting that the quantitative perfusion histogram of DCE-MRI in lung cancer can reflect the MVD value of cancer tissue .

Cerebral lesions of DWI hyperintensity in patients with subacute stroke assessed by intravoxel incoherent motion technique / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the cerebral lesions of diffusion weighted imaging (DWI) hyperintensity in patients with subacute stroke with intravoxel incoherent motion (IVIM) technique.</p><p><b>METHODS</b>The clinical data of 20 patients with ischemic stroke (3 to 7 d after onset) who underwent DWI and IVIM scanning between June 2014 and July 2015, were retrospectively analyzed. The parameters from IVIM including slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) were processed. DWI hyperintensity was segmented by its signal intensity greater than the mean+2 standard deviations of the value in the homologous contralateral region. Then, DWI hyperintensity was classified into two regions of interest (ROIs): infarction core and peri-core with the ADC threshold of 0.55 × 10⁻³ mm²/s. The mirrored ROIs of infarction core and peri-core were also obtained. Then, we measured the values of ADC and D, D(*) and f in these ROIs. The ratios of ADC (rADC), D (rD), D(*) (rD(*)) and f (rf) were also calculated (e.g., rADC=ADCinfarction core/ADCmirrored region).</p><p><b>RESULTS</b>Compared with mirrored region, ADC, D and f in the infarction core region decreased by 45% (P<0.001), 42% (P<0.001) and 32% (P<0.001), respectively; while ADC, D and f in the peri-core region decreased by 22% (P<0.001), 32% (P<0.001) and 8% (P=0.009), respectively. The values of rADC, rD, rD(*) and rf in the infarction core region were significantly lower than those in the peri-core region (all P<0.001). Pearson analysis showed that rADC was positively correlated with rf in the peri-core region (r=0.467, P=0.038).</p><p><b>CONCLUSION</b>During subacute stage of stroke, compared to the infarction core region within DWI hyperintensity, D and f increase in the peri-core region of DWI hyperintensity, reflecting the increased water diffusion in microstructure and perfusion volume in microvasculature. This result shows that the potential reason for the heterogeneous ADC signal is associated with the disappearance of cellular edema and microvascular compensatory with increased blood volume.</p>

Hepatic Sinusoidal Obstruction Syndrome Caused by Herbal Medicine: CT and MRI Features

OBJECTIVE: To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. MATERIALS AND METHODS: The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. RESULTS: Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). CONCLUSION: Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

Magnetic resonance signal detection of superparamagnetic iron oxide nanoparticles and its biological effects on endothelial cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the magnetic resonance (MR) signal changes of superparamagnetic iron oxide (SPIO) and its biological effects on endothelial cells.</p><p><b>METHODS</b>The citric-acid coated SPIO was synthesized by co-precipitation method. The human umbilical vein endothelial cells (HUVECs) were incubated with SPIO for 24 h in culture medium at iron concentration of 0.01, 0.05, 0.10, 0.15 mg/ml (experimental groups), and the cells incubated without SPIO served as control groups. The uptake efficiency of intracellular iron was measured by Prussian blue staining, and the cell viability was monitored by Calcein-AM method. The cell cytoskeleton (F-actin and tubulin), adherence and migration capacity were measured by immunofluorescence staining. The iron oxide nanoparticles distribution and the cellular organelle change were monitored by transmission electron microscopy (TEM). Quantification of particle uptake was measured by atomic absorption spectrometry. The MR signal of endothelial cells after labeling was monitored by Philips 3.0 T MR scanner.</p><p><b>RESULTS</b>SPIO was uptaken by HUVECs in a concentration-dependence manner. Compared with the control group, cell viability was decreased along with the increase of iron concentration. Compared with the control group, the cell cytoskeleton was markedly disorganized and the FAK spot was bigger and sparser.The nanoparticles were mainly existed in lysosomes, and the higher concentration of SPIO, the more lysosomes and vacuoles presented in the cells. The iron content per cell was (55.86 +/-9.935) pg when the SPIO concentration was 0.15 mg/ml. The MR image showed that the cells labeled with SPIO resulted in the decrease of MR signal.</p><p><b>CONCLUSION</b>The cells labeled with SPIO can be detected by MR. The cell viability, cytoskeleton, adherence and migration capacity of HUVECs are affected by citric-acid coated SPIO in a concentration-dependent manner.</p>

Magnetic resonance signal features of superparamagnetic iron oxide with different particle size and concentration / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the magnetic resonance (MR) signal features of superparamagnetic iron oxide (SPIO) with different particle size and concentration.</p><p><b>METHODS</b>The superparamagnetic iron oxide with different concentration and particle size was scanned by magnetic resonance; T1, T2 and T2(*) values of each group were recorded to evaluate the features of MR signals.</p><p><b>RESULTS</b>The T1 value of SPIO with different particle size had negative linear relationship with concentration. In low concentration the T2 and T2(*) values were elevated markedly with the particle size decreased; while in high concentration the T2 and T2(*)values were elevated gently with particle size decreased. lg(T2), particle size and concentration of SPIO had linear relationship.</p><p><b>CONCLUSIONS</b>SPIO affects magnetic resonance signal mainly with effect on T1 and T2. T2 value can be regarded as the major detection index in the magnetic resonance scan of SPIO. There is a linear relationship among particle size, SPIO concentration and lg(T2) value.</p>

MRI scan of striatum volume in healthy adults / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To examine the age, sex, and hemispheric differences in volume of the striatum by MRI in healthy adults.</p><p><b>METHODS</b>The volumes of the bilateral caudate nucleus and putamen were measured on MR images in 100 healthy right-handed adults (18-70 y).</p><p><b>RESULTS</b>The volume of bilateral caudate nucleus and putamen in healthy adults was (8.42 +/-0.88) cm(3) and (8.90 +/-0.89) cm(3), which were decreased with aging (for caudate nucleus r=-0.727, P<0.001; for putamen r=-0.709, P<0.001). The average annual shrinkage rate was 0.52 % in the caudate nucleus and 0.50 % in the putamen. There were no gender differences in the volume of the striatum, however, the age-related shrinkage of the striatum was more evident in men than that in women. The volume of the left caudate nucleus (t=4.43, P<0.001) and the putamen (t=4.88, P<0.001) was greater than that of its right counterpart.</p><p><b>CONCLUSION</b>Bilateral age-related shrinkage of the striatum is found in healthy adults, which is more evident in men than that in women. In both sexes, significant leftward asymmetry in volume of the caudate nucleus and the putamen is found.</p>

Role of activated brain regions during tactile stimulation in early Parkinson's disease: a preliminary fMRI study / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the role of activated brain regions in Parkinson's disease (PD) during tactile stimulation.</p><p><b>METHODS</b>Twenty-one patients with early PD[mean age (60.43 +/-9.65)y] and twenty-two age-matched healthy controls [mean age (59.23 +/-11.12)y] were enrolled in the study. All the patients were tested by the United Parkinson Disease Rating Scale (UPDRS) as the evaluation of the disease severity. A block design was used when the finger tactile stimulation was given to the subjects. The hypoactive and hyperactive regions of PD patients were confirmed first, which were identified as regions of interest (ROI). ROI analysis was performed to quantify BOLD signal changes when subjects were under tactile stimulation. The correlations of signal changes with disease severity, and correlations of hyperactive with hypoactive regions were analyzed.</p><p><b>RESULTS</b>Right primary sensory and motor cortex, right supplementary motor area (SMA), bilateral caudates, bilateral precuneus, bilateral occipital visual cortex and left middle temporal gyrus were hypoactivated in PD, while right prefrontal cortex (PFC) and right caudate were hyperactivated. The hypoactivation of right SMA was negatively correlated with disease severity. All the hypoactive and hyperactive regions were positively correlated with activation of caudates. There was a positive correlation between hyperactive PFC and hypoactive regions.</p><p><b>CONCLUSIONS</b>The signal change of SMA is directly related to disease severity in early PD, and caudates may play a significant role in PD tactile processing. The hyperactivation of PFC may be not a compensation but a pathophysiological change related to PD neural dysfunction.</p>

Biochemical metabolic changes detected by phosphorus-31 MR spectroscopy in liver of fasting rabbits / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the biochemical metabolic changes detected by phosphorus-31 MR spectroscopy ((31)P MRS) with pathologic changes in the liver of fasting rabbits.</p><p><b>METHODS</b>A total of 22 rabbits were under the starvation up to death to establish animal models. Hepatic (31)P MRS was performed in different period of 10 rabbits including normal condition, over-starvation, agonal condition and death after 30 min. Other 9 rabbits were divided into three type including over-starvation, agonal condition and death group with 3 rabbits in each group, and 3 healthy rabbits served as controls. All the 12 rabbits were sacrificed for the hepatic pathological examination. The MR examination was performed on a 1.5 T imager using a 1H/31P surface coil by the 2D chemical shift imaging technique. The relative quantities of phosphomonoesters (PME), phosphodiesters (PDE), inorganic phosphate (Pi) and adenosine triphosphate (ATP) were measured.</p><p><b>RESULTS</b>All the relative quantification of phosphorus metabolites were changed significantly from starvation to death (X(2)=23.13-35.41, P<0.01). The relative quantifications of ATP of normal condition, over-starvation, agonal condition and death were 2.54 +/-0.53, 1.73 +/-0.14, 0.88 +/-0.23 and 0.05 +/-0.08, respectively (rs=1.0, P<0.01). The relative quantifications of PDE from normal to death were 1.25 +/-0.54, 2.76 +/-0.23, 3.33 +/-0.49 and 3.87 +/-0.43, respectively, and those of Pi were 0.42 +/-0.02, 0.65 +/-0.05, 0.89 +/-0.15 and 0.99 +/-0.08, respectively (rs=1.0, P <0.01). The relative quantifications of PME were also significantly changed (rs=0.4, P=0.6). The pathologic changes of normal condition, over-starvation, agonal condition and death: decreased size of hepatocytes, loss of cell number, cellular swelling, degeneration and cell necrosis or hepatic hemorrhage became more and more pronounced.</p><p><b>CONCLUSION</b>(31)P MRS can monitor dynamic changes of relative quantification of phosphorus metabolites, which are correlated with the pathological severity of acute hepatic injury by fasting.</p>

Evaluation of biochemical metabolites by 31P MR spectroscopy in leukemic infiltration of liver / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the changes of phosphorus metabolites in leukemic infiltration of liver (LIL) with two-dimensional chemical shift imaging(2D CSI)(31)phosphorus MR spectroscopy ((31)P MRS).</p><p><b>METHODS</b>Fifteen patients with LIL and 12 healthy subjects (control group) were scanned with liver 2D CSI(31)P MRS by a 1.5T MR Scanner(Sonata, Siemens Corporation). Relative quantification of phosphorus metabolites including phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE) and beta-adenosine- triphosphate (beta-ATP) were detected and after calibrated with model factor, the ratios of PME/PDE, PME/(PME+PDE), PME/ATP, PDE/ATP and Pi/ATP were analyzed.</p><p><b>RESULTS</b>Compared with control group, the PME value, PME/PDE ratio, PME/(PME+PDE) ratio and PME/ATP ratio were increased in LIL group (1.992 +/-0.876 Compared with 1.167 +/-0.427, P <0.05), (0.551 +/-0.339 Compared with 0.254 +/-0.059,P <0.01), (0.326 +/-0.13 Compared with 0.199 +/-0.049, P <0.01)and (1.402 +/-0.654 Compared with 0.792 +/-0.232, P <0.01) respectively.</p><p><b>CONCLUSION</b>(31)P MRS examination can be used as a non-invasive procedure to evaluate the changes of phosphorus metabolites of leukemic infiltration of liver. The increase of PME value and its ratios to PDE, ATP and PME+PDE may indicate leukemic infiltration of liver.</p>

Evaluation of kidney oxygen bioavailability in acute renal failure by blood oxygen level dependent magnetic resonance imaging / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the kidney oxygen bioavailability in acute renal failure using blood oxygen level dependent (BOLD) magnetic resonance (MR) imaging.</p><p><b>METHODS</b>Twenty-one patients with acute renal failure, including 18 patients with oliguric renal failure, 1 nonoliguric acute renal failure and 2 functional renal failure were enrolled in the study; 20 healthy subjects served as controls. All subjects received renal functional MR examination. BOLD MR imaging with 16 gradient-recalled-echoes on a 1.5-T scanner were performed. R2(*)(1/sec) values of the cortex and medulla and R2(*) ratio of the medulla to cortex (R2(*) ratio of M/C) of the renal were recorded respectively.</p><p><b>RESULTS</b>The R2(*) values of the medulla was higher than those of the cortex in controls (17.64 +/-1.86/sec vs 13.73 +/-0.49/sec, P<0.00). The R2(*) ratio of M/C in controls was 1.28 +/-0.06. The R2(*) values of the medulla (13.31 +/-4.28/sec) and cortex (12.25 +/-2.41/sec) and the R2(* ) ratio of M/C (1.01 +/-0.25) in oliguric renal failure were lower than those in controls (P <0.05). Patients with functional renal failure and nonoliguric acute renal failure had higher R2(*) values in cortex and medulla and higher R2(*) ratio of M/C than those of controls.</p><p><b>CONCLUSION</b>BOLD MRI demonstrates that decreased R2(*) values of cortex and medulla suggest lower oxygen bioavailability in acute renal failure and decreased R2(*)ratio of M/C suggests the disappearance of a steep cortico-medullary gradient of oxygen.</p>

Value of diffusion-weighted MR imaging in diagnosis of acute rejection after renal transplantation / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the feasibility of MR diffusion-weighted imaging (DWI) in diagnosis of acute rejection after renal transplantation.</p><p><b>METHODS</b>Sixty-nine patients who underwent renal transplantation were enrolled in the study. According to the clinical features and renal biopsy, 26 patients were designated in rejection group and 43 in non-rejection group. Patients in non-rejection group underwent MR DWI scan at 2 to 3 weeks after operation, and those in rejection group underwent scan at 5 d before or after renal biopsy. Then the apparent diffusion coefficient (ADC) values of transplanted kidneys were measured with high diffusion sensitivity gradient factors (b values).</p><p><b>RESULTS</b>Patients with acute rejection had significantly lower ADC (P <0.04) than non-rejection patients with all the different b values (b=200, 400, 600, 800, 1,000 s/mm(2)). The ROC curves showed that sensitivity and specificity were best when b value was 800 s/mm(2).</p><p><b>CONCLUSION</b>DWI is a potential and reliable non-invasive method for the diagnosis of the acute rejection after renal transplantation.</p>

Functional MR study of hepatic fibrosis / 浙江大学学报·医学版

The accurate diagnosis and staging of hepatic fibrosis is crucial for treatment and prognosis of liver disease. The current gold standard is liver biopsy, but it cannot be used in population-based screening, and has well known drawbacks if used for monitoring of disease progression or treatment results. Functional MR, as a non-invasive method, is increasingly used in hepatic fibrosis and became the current hot spot. Most recently available functional MR imaging techniques including diffusion weighted imaging, perfusion weighted imaging and MR spectroscopy can detect cirrhosis or fibrosis reasonably accurately. However, to date only MR elastography has been able to stage fibrosis or diagnose mild disease. MR diffusion weighted appears next most promising.

Asymmetry in internal capsule detected with magnetic diffusion tensor imaging / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the asymmetry of fibers in the posterior limb of the internal capsule with diffusion tensor imaging.</p><p><b>METHODS</b>Twenty-nine volunteers (right-handers: 20, left-handers: 9) were enrolled in this study. All the data were obtained using a 1.5 tesla scanner (Signa EXCITE II. GE Medical Systems). The parameters including apparent diffusion coefficient (ADC), fractional anisotropy (FA) and eigenvalue lambda1, lambda2, lambda3 were acquired from the posterior limb of the internal capsule in both hemisphere of brain, and paired t-test was used for statistical differences between the hemisphere.</p><p><b>RESULTS</b>No differences of ADC and lambda1 were found among the right-handers, but FA in the internal capsule of left hemisphere was larger than that in the right (0.72+/-0.03 compared with 0.70 +/-0.04, P=0.001), and lambda2, lambda3 in the left was lower than that in the right [(4.39+/-0.32 compared with 4.50+/-0.33)x10(-3) mm(2)/s, P=0.016 and (2.19 +/-0.34 compared with 2.29 +/-0.40)x10(-3) mm(2)/s, P=0.024, respectively]. In contrast to the results among the right-handers, all parameters in the left-handers showed no statistical differences.</p><p><b>CONCLUSION</b>The fibers in the posterior limb of the internal capsule of left hemisphere might be well sheathed with myelin among right-handers.</p>

Are there gender differences in iron contents of adult brain: an in vivo susceptibility weighted imaging study / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the gender-related difference in the iron contents of the human brain.</p><p><b>METHODS</b>The brain iron levels were evaluated in vivo in 78 healthy adult volunteers using a noninvasive magnetic resonance method termed susceptibility weighted phase imaging. The subjects consisted of 40 males and 38 females, with the mean age of 41.5+/-11.9 and 45.2+/-15.9, respectively. 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. Phase values of these regions measured from the subjects aged over 30 were correlated with published values of brain iron contents in normal adults to check the validity of the data. Covariance models were used to evaluate the gender effect on the brain iron concentration, with age as the covariate, controlling for the linear effects of age.</p><p><b>RESULTS</b>A strongly negative correlation was showed between the phase values of this study and the reference values (r=-0.796, P=0.032). No significant gender-related difference in the brain iron concentration was found in any regions of interest (P>0.05).</p><p><b>CONCLUSION</b>Gender differences in the iron contents of the adult human brain are not found in this study.</p>

Different patterns of aversive emotion regulation in homosexual and heterosexual men / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To compare the differences between homosexual and heterosexual men in the pattern of induced aversive emotion regulation.</p><p><b>METHODS</b>Ten healthy homosexual men and 10 heterosexual men were investigated by functional magnetic resonance imaging under three types of visual sexual stimuli designed by Block. SPM2 software was used for data analysis.</p><p><b>RESULTS</b>Same levels of negative emotions of homosexual men and heterosexual were induced by female-female and male-male erotic stimuli respectively. Activations of same brain regions including prefrontal gyrus, temporal gyrus, occipital gyrus and cerebellum were observed in two groups. However, there were significant differences in the side of hippocampus and precuneus. Activations of right cingulate cortex were observed in homosexual men, but not in heterosexual men.</p><p><b>CONCLUSION</b>There are some differences in the patterns of aversive emotion regulation between homosexual and heterosexual men.</p>

Experimental study of hippocampal neuronic lesion in ischemic rat by magnetic resonance spectroscopy / 中国应用生理学杂志

<p><b>AIM</b>To evaluate N-acetylaspartate reflecting the neuronal lesion in middle cerebral artery occlusion and reperfusion rat by magnetic resonance spectroscopy (MRS).</p><p><b>METHODS</b>Sixteen adult Wistar rats with MCAO reperfusion and ten pseudooperation rats were performed MRS in vivo at the sixth weeks, then pathologic examination of HE staining and immunohistochemical staining were made. We compared hippocampus modality, cell density and immunohistochemical results with N-acetylaspartate, creatine changes and ration of NAA/Cr.</p><p><b>RESULTS</b>The values of NAA, Cr and NAA/Cr of ipsilateral hippocampus lesion in MCAO reperfusion rats (2.05 +/- 0.33, 2.42 +/- 0.41 and 0.86 +/- 0.10) were visiblly decreased than contralateral hippocampus (3.45 +/- 0.58, 3.10 +/- 0.93, 1.18 +/- 0.32) and control group (3.42 +/- 0.43, 3.57 +/- 0.47, 0.98 +/- 0.14). But the level of decreased NAA is not corresponding to the degree of neuronal death in ipsilateral region of hippocampus in histochemistry.</p><p><b>CONCLUSION</b>MRS has perfect explanation of cell metabolic changes in CA1 region. Decrease of NAA represented neuron delayed injury. But the decreased level of NAA is not perfectly corresponded to the degree of neuron lost. This change has closed correlation with reactive astrocytes proliferation.</p>

Low-dose spiral CT versus standard dose CT in detection of pulmonary metastasis from gestational trophoblastic tumor / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The purpose of this study is to investigate whether low-dose spiral chest CT scan can replace standard-dose CT scan in detecting pulmonary metastases for patients with gestational trophoblastic tumor (GTT).</p><p><b>METHODS</b>Totally, 34 GTT patients underwent 56 chest CT scans for the assessment of pulmonary metastasis. All patients received CT examination both at standard-dose (120 KV, 150 mAs, pitch 1, and a standard reconstruction algorithm) and low-dose CT (120 KV, 40 mAs, pitch 2, and a bone reconstruction algorithm) simultaneously each time. The images were interpreted by two radiologists independently. A metastasis by CT image was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of lesions detected at each dose protocol was recorded. The size of each lesion was measured and categorized as < 5 mm, 5 - 10 mm or > or = 10 mm. The differences in detection of the lesions between the standard- and low-dose CT protocols were compared using Wilconxon signed rank test.</p><p><b>RESULTS</b>1417 lesions were detected at the standard-dose, whereas 1214 lesions were found by low-dose CT. Lesions < 5 mm detected by low-dose CT were fewer than that detected by standard-dose CT (Z = -3.368, P = 0.000), though there was no statistically significant difference between the standard- and low-dose CT in detecting lesion > or = 5 mm (Z = -0.055, P = 0.957). Moreover, the risk score of the patients was not affected either. The sensitivity of low-dose CT was 69.16% for all size of lesions, 58.50% for < 5 mm, 87.07% for 5 - 10 mm, and 97.01% for > or = 10 mm. The positive predictive value for different sizes of lesion was 80.71% (all sizes), 73.82% (5 mm), 88.86% (5 - 10 mm), and 98.48% (> or = 10 mm), respectively.</p><p><b>CONCLUSION</b>Low-dose chest CT can replace the standard-dose chest CT as a screening and follow-up examination to assess the change in pulmonary metastasis for patients with gestational trophoblastic tumor.</p>

Sensitivity encoding technology in MRI / 中国医疗器械杂志

This article introduces the principle and image reconstruction algorithm and SNR of sensitivity encoding technology in magnetic resonance imaging.

Cortical language activation in aphasia: a functional MRI study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Functional neuroimaging has been used in neurolinguistic research on normal subjects and on patients with brain damage. This study was designed to investigate the differences of the neural basis underlying language processing between normal subjects and aphasics.</p><p><b>METHODS</b>Functional magnetic resonance imaging (fMRI) was used to map the language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed a word generation task during multi-slice functional scanning for the measurement of signal change associated with regional neural activity induced by the task.</p><p><b>RESULTS</b>In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions. In the patient group, however, no activation was detected in the left inferior frontal gyrus whether the patient had a lesion in the left frontal lobe or not. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects.</p><p><b>CONCLUSIONS</b>fMRI with word generation task is feasible for evaluating language function in aphasic patients. Remote effect of focal lesion and functional redistribution or reorganisation can be found in aphasic patients.</p>

Effects of age on the lenticular nuclei detected by MR diffusion tensor imaging / 中华放射学杂志

50 years).The values of ADC,FA,?_1,?_2 and ?_3 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,?_1,?_2 and ?_3 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)?10~(-4),(6.47?0.36)?10~(-4),(6.44?0.34)?10~(-4)mm~2/s]than that in the golbus pallidus[(6.13?0.50)?10~(-4),(6.05?0.33?10~(-4),(6.05?0.52)?10~(-4)mm~2/s],and the value of FA in the putamen(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 ?_3 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