Signifiance of brush sign on susceptibility-weighted imaging predicts hemorrhagic transformation after intravenous thrombolysis in patients with acute ischemic stroke / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess brush sign (BS) on susceptibility-weighted imaging (SWI) in prediction of hemorrhagic transformation (HT) in patients with acute ischemic stroke (AIS) after intravenous thrombolysis(IVT).</p><p><b>METHODS</b>Patients with acute cerebral ischemic stroke, who had major cerebral artery occlusion (internal carotid artery, middle cerebral artery M1 and M2), treated with intravenous recombinant tissue plasminogen activator (rt-PA) from August 2009 to October 2014 in the Second Affiliated Hospital, Zhejiang University School of Medicine, were enrolled in the study. All patients underwent SWI scanning. The asymmetry index (AI) was defined as the difference of intensity between ischemic and normal hemispheres on the SWI phase map; according to AI values patients were divided into 3 groups: BS=0(n=9), BS=1 (n=39) and BS=2 (n=18). The relationships between BS and HT and the clinical outcome among the 3 groups were analyzed.</p><p><b>RESULTS</b>Sixty-six patients aged 68 ± 13 years were included in the study, including 44 males (67%) and 22 females (33%), and 44 (67%) with acute ischemic stroke. The mean pre-treatment National Institutes of Health Stroke Scale (NIHSS) score was 13 (6-17), and the onset to needle time was (252 ± 88) min. Twenty-six (39.4%) patients had HT, including 18 cases (27.3%) with HI and 8 cases (12.1%) with PH; BS was observed more frequently in HT group than non-HT group. Binary logistic regression analysis showed that BS was independently associated with HT of patients with acute ischemic stroke following IVT (OR=2.589, 95% CI: 1.080-6.210, P=0.033). In those without reperfusion after IVT, patients with higher BS grade had higher HT rate (P=0.023).</p><p><b>CONCLUSION</b>Brush sign on SWI can be used for predicting hemorrhagic transformation after intravenous thrombolysis in patients with acute ischemic stroke.</p>

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>

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>

Three-dimensional reconstruction of brain surface anatomy:technique comparison between flash and diffusion-weighted imaging / 中华放射学杂志

Objective To compare two methods 3D flash and diffusion-weighted images(DWI)in reconstructing the brain surface anatomy,and to evaluate their displaying ability,advantages,limitations and clinical application.Methods Thrity normal cases were prospectively examined with 3 D flash sequence and echo-planar DWI.Three-dimensional images were acquired with volume-rendering on workstation.Brain surface structures were evaluated and scored by a group of doctors.Results Main structures of brain surface were clearly displayed on three-dimensional images based on 3D flash sequence.Average scores were all above 2.50.For images based on DWI,precentral gyrus,postcentral gyrus,superior parietal lobule, superior frontal gyrus,precentral sulcus,central sulcus,postcentral sulcus,intraparietal sulcus and superior frontal sulcus were best shown with average scores between 2.60-2.75,However,supramarginal gyrus, angular gyurs,middle frontal gyrus,inferior frontal gyrus,superior temporal gyrus,lateral sulcus,inferior frontal sulcus could not be well shown,with average scores between 1.67-2.48.Middle temporal gyrus, inferior temporal gyrus,superior temporal sulcus and inferior temporal sulcus can only get scores from 0.88 to 1.27.Scores of images based on 3D flash were much higher than that based on DWI with distinct differentiations,P values were all below 0.01.Conclusion Three-dimensional images based on 3D flash can really display brain surface structures.It is very useful for anatomic researches.Three-dimensional reconstruction of brain surface based on DWI is a worthy technique to display brain surface anatomy, especially for frontal and parietal structures.