Value of susceptibility weighted imaging in glioma classification / 国际肿瘤学杂志

Objective To study the characteristics of susceptibility weighted imaging (SWI) and it's role in glioma classfication. Methods 45 glioma patients with pathologically confirmion, underwent preopera-tive plain MRI, enhanced MRI and SWI examination. By using double blind method, the score of T1 WI, T2WI, enhanced T1 WI, SWI and enhanced SWI were acquired to display enhancing tumor, peritumoral edema, tumor hemorrhage and tumor vein. The tumor volume of low signal areas was measured by using measurement software to acquire the bleeding of tumor. Results In 26 cases of high grade gliomas,18 patients with intratu-moral, multiple patchy low signal cords in varying degrees, which were proved by pathology as tumor hemorrhage and tumor blood vessels; in 19 case of low grade gliomas, 10 cases occured a few spots, linear low signal in tumor, which were proved by pathology as tumor hemorrhage; the bleeding of high grade gliomas was higher than that of the low level group ( P < 0.05 ). SWI was superior to T, WI, T2 WI on displaying tumor hemorrhage and tumor vein(P<0. 05). Conclusion Different grades of glioma show obvious different display on SWI, and SWI probably be helpful for evaluation of glioma grading preoperatively.

Diffusion-weighted magnetic resonance imaging in glioma classification / 国际肿瘤学杂志

Objective To evaluate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficients (ADC) in differentiating tumor, edema, and normal brain tissue, and in classification of cerebral gliomas. Methods Using Philips Achieva 1.5T super conduct MR scanner, 46 patients with gliomas underwent conventional MR imaging and DWI. The ADC of regions of interest ( ROI ) were measured with two different b values, 0s/mm2 and 1000s/mm2. ROIs were manually placed over areas of tumor,edema, and normal brain tissue. Results The signals of DWI and ADC map in tumor tissue were respectively higher and lower than those in normal brain tissue. The ADC values in tumor were 1.68 ± 0.18,1.65 ± 0.20,1.29 ±0.16,1.21 ±0.21 for grade Ⅰ、Ⅱ、Ⅲ、Ⅳ gliomas, respectively; the corresponding figures in edema were 1.74 ±0.22,1.72 ±0.19,1.35 ±0.20,1.28 ±0.19, respective. The ADC values in tumor were not significantly different from the values in edema (P ＞0.05); however, both values were significantly different from those in normal brain ( P ＜0.05 ). The ADC value of low grade ( grade1-2 ) gliomas was significantly higher than that of high grade (grade3-4) glioma (P＜0.05). Conclusion ADC values can aid in distinguishing tumors from normal tissues, but can not distinguish tumors from adjacent edema. Individually, ADC values overlapped considerahly. ADC value is associated with cellularity of gliomas. DWI can help characterizing the malignancy of gliomas.

Application of diffusion tensor imaging in brain tumors / 国际肿瘤学杂志

Objective To study the characteristics of diffusion tensor imaging (DTI) in brain tumor and it's diagnosis and differential diagnosis value.Methods Thirty-nine patients with brain tumors proven by pathologically (10 meningioma,17 glioma,12 metastatic tumors) were enrolled,by using Philips Achieva 1.5 T MRI,conventional MRI and DTI were underwent on them,fractional anisotropy (FA) maps,apparent diffusion coefficient (ADC) maps and three dimensional white matter fiber bundle map were reconstructed in the workstation.The core substance of the tumor area and the contralateral mirror area were selected as the region of interest,and FA and ADC values of them were measured,and t test was performed.Results The FA values of meningioma,metastases tumors and gliomas were 0.36 ± 0.08,0.28 ± 0.03,0.18 ± 0.06,respectively,and the differences among them were significant( P ＜ 0.05).The ADC values of meningioma,metastases tumors and gliomas were 1.72 ± 0.10,1.52 ± 0.22,1.34 ± 0.14,respectively,and the differences among them were significant( P ＜ 0.05).Conclusion DTI has high clinical value in identification of meningiomas,metastatic tumors and glioma.

Application research of magnetic resonance diffusion tensor imaging combined with diffusion tensor tractography in cerebral infarction / 国际生物医学工程杂志

ObjectiveTo analyze the characteristics of magnetic resonance diffusion tensor imaging(DTI)and diffusion tensor tractography (DTIT) in patients with cerebral infarction, and explore the diagnosis values and prognosis of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) in patients with cerebral infarction in different stages. Methods58 patients with cerebral infarction in different stages and 25 healthy volunteers were examined by magnetic resonance imaging(MRI), including conventional T1 and T2 weighted imaging, DWI and DTI. Fractional anisotropy (FA) images were reconstructed. The values of FA and apparent diffusion coefficient (ADC) were measured in the infarcted regions, corresponding contralateral normal regions and corresponding normal regions in normal control group. Results①DWI and DTI showed size of infarction focus was more accurate and clearer than that of conventional MRI; ②The FA and ADC values of the infarcted regions during superacute stage, acute stage, subacute stage and chronic stage were (0.24±0.02, 0.31 ±0.11), (0.20±0.02, 0.32±0.12), (0.18±0.02, 0.34±0.11) and (0.16±0.02, 0.37±0.13), respectively, lower than those in the contralateral corresponding regions which were (0.40±0.03, 0.70±0.21), (0.37±0.03, 0.71±0.21), (0.39±0.03, 0.72±0.22) and (0.40:±0.03, 0.72±0.23), respectively. The differences were statistically significant (P＜0.05). The FA and ADC values had no significant differences between the uninjured sides in patients with cerebral infarction and the corresponding regions in the normal control group (P＞0.05); ③The FA and ADC values in brain tissues changed regularly with the time of infarction after cerebral infarction. The FA values in the affected sides had no consistent changes as compared with the contralateral sides in the superacute stage. They increased or decreased slightly, then (during acute stage, subacute stage and chronic stage) decreased irreversibly. The ADC values in the affected sides changed with time regularly, they decreased significantly, gradually returned to normal, and then increased again. Conclusion DTI and DTT examination contribute to the diagnosis of cerebral infarction. The combination of the FA and ADC values may more accurately conduct clinical staging and evaluate the time of the occurrence of cerebral infarction.

The value of MR diffusion weighted imaging in differentiating benign and malignant lesions of prostate / 中国医师进修杂志

Objective To study the value of MR diffusion weighted imaging(DWI)and apparent diffusion coefficient(ADC)in differentiating benign and malignant lesions of prostate.Methods Twenty-two patients with prostate cancer and 17 patients with benign prostatic hyperplasia confirmed by pathology or biopsy,and 20 healthy volunteers were underwent prostate plain MRI,DWI and enhanced MRI,and measuring the value of ADC in the regions of interest in the workstation,and the ADC values of prostate cancer,benign prostatic hyperplasia,normal prostate were analyzed statistically.Results The ADC of prostate cancer,benign prostatic hyperplasia,normal prostate in central gland and peripheral zone were 1.08 ±0.23,1.43 ±0.27,1.51 ±0.26 and 1.26 ±0.47,1.72 ±0.40,1.75 ± 0.28,respectively,the ADC of prostate cancer was significantly lower than that of benign prostatic hyperplasia and normal prostate,and there was significant difference(P＜ 0.05),but there was no significant difference between benign prostatic hyperplasia and normal prostate(P ＞0.05).Looking the ADC was 1.30 and 1.60 in central gland and peripheral zone as the threshold to distinguish benign and malignant lesions of prostate,had high sensitivity and specificity.Conclusion The application of DWI combined with ADC,has improved the capability of diagnosis and differential diagnosis in benign and malignant lesions of prostate greatly.