Comparative Study of Dynamic Susceptibility Contrast Perfusion MR Images between Warthin's Tumor and Malignant Parotid Tumors / 고신대학교의과대학학술지

OBJECTIVES: To identify diagnostically meaningful differences between Warthin's tumor and malignant masses in the parotid gland by dynamic susceptibility contrast (DSC) MR imaging. METHODS: Eleven malignant parotid tumors and 9 Warthin's tumors were included. MR imaging was performed on all patients. Signal intensity time curves of tumors were obtained by DSC MR imaging and dynamic susceptibility contrast percentages (DSC%) were calculated. RESULTS: No significant difference was observed between malignant tumors and Warthin's tumors (P = 0.437), although DSC% values tended to be higher for Warthin's tumors. CONCLUSIONS: Warthin's tumor tended to have higher DSC% values than malignant parotid tumors, but this difference was not significantly different.

Evaluation of Tumor Blood Flow Using Alternate Ascending/Descending Directional Navigation in Primary Brain Tumors: A Comparison Study with Dynamic Susceptibility Contrast Magnetic Resonance Imaging

OBJECTIVE: Alternate ascending/descending directional navigation (ALADDIN) is a novel arterial spin labeling technique that does not require a separate spin preparation pulse. We sought to compare the normalized cerebral blood flow (nCBF) values obtained by ALADDIN and dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI) in patients with primary brain tumors. MATERIALS AND METHODS: Sixteen patients with primary brain tumors underwent MRI scans including contrast-enhanced T1-weighted imaging, DSC perfusion MRI, and ALADDIN. The nCBF values of normal gray matter (GM) and tumor areas were measured by both DSC perfusion MRI and ALADDIN, which were compared by the Wilcoxon signed rank test. Subgroup analyses according to pathology were performed with the Wilcoxon signed rank test. RESULTS: Higher mean nCBF values of GM regions in the bilateral frontal lobe, temporal lobe, and caudate were detected by ALADDIN than by DSC perfusion MRI (p <0.05). In terms of the mean or median nCBF values and the mean of the top 10% nCBF values from tumors, DSC perfusion MRI and ALADDIN did not statistically significantly differ either overall or in each tumor group. CONCLUSION: ALADDIN tended to detect higher nCBF values in normal GM, as well as higher perfusion portions of primary brain tumors, than did DSC perfusion MRI. We believe that the high perfusion signal on ALADDIN can be beneficial in lesion detection and characterization.

Application of MR perfusion weighted imaging in clinical diagnosis and treatment of acute cerebral infarction / 中国脑血管病杂志

Magnetic resonance (MR) perfusion weighted imaging (PWI) is a functional MR imaging technique that reflects the distribution of tissue microvessels and blood perfusion. In recent years,with the development of MR technology, PWI has been widely used in the clinical diagnosis and treatment of cerebral infarction. Dynamic susceptibility contrast-enhanced imaging can delineate the ischemic penumbra and evaluate the compensation of collateral circulation. Dynamic contrast-enhanced imaging can reflect the integrity of blood-brain barrier, evaluate risk of the hemorrhagic transformation and the compensation of collateral circulation. The technique of arterial spin labeling can also be used to delineate ischemic penumbra, confirm the perfusion around the infarct core,and to evaluate the collateral circulation. The relevant studise on MR PWI in acute cerebral infarction will be reviewed.

Multimodal MRI manifestations of diffuse midline glioma, H3 K27M mutant / 中国医学影像技术

Objective: To investigate multimodal MRI features of diffuse midline glioma, H3 K27M mutant. Methods Multimodal MRI features, including plain and enhanced MRI, DWI and dynamic susceptibility contrast (DSC)-PWI of 10 patients with pathologically proved diffuse midline glioma, H3 K27M mutant were retrospectively analyzed. The location, size, edema, signal characteristics, diffusion, enhancement characteristics, etc. of the tumors were observed. Results Among 10 patients, 8 lesions located at thalamus, 1 at medulla and cervical cord, 1 at hypothalamus. The mean maximum tumor diameter was (5.56±0.42)cm, and the mean peritumoral edema distance was (1.33±0.34)cm. The tumors appeared as low signal intensity on T1WI and high signal intensity on T2WI, with small patchy short T1 and short T2 signal within lesions. Cystic lesions were observed in 3 lesions, and necrosis and hemorrhage were found in both 7 lesions. Nine lesions demonstrated marked enhancement, with ringlike pattern in 5 lesions, nodular pattern in 3 lesions and patchy pattern in 1 lesion. There was no enhancement in 1 lesion. Hydrocephalus were found in 9 patients. DWI showed restricted diffusion in 8 patients, with mean relative ADC of 1.26±0.12 and minimum relative ADC of 1.12±0.12. In 5 patients who underwent DSC-PWI, markedly high perfusion was demonstrated in 3 patients, moderate perfusion in 1 patient and low perfusion 1 patient demonstrated. The maximum relative cerebral blood volumewas 2.92±0.49. Conclusion: Multimodal MRI manifestations of diffuse midline glioma, H3 K27M mutant are various, but similar to those of high-grade gliomas. Molecular pathology may be considered for deferential diagnosis.

Dynamic Susceptibility Contrast (DSC) Perfusion MR in the Prediction of Long-Term Survival of Glioblastomas (GBM): Correlation with MGMT Promoter Methylation and 1p/19q Deletions

PURPOSE: To investigate the surgical, perfusion, and molecular characteristics of glioblastomas which influence long-term survival after treatment, and to explore the association between MR perfusion parameters and the presence of MGMT methylation and 1p/19q deletions. MATERIALS AND METHODS: This retrospective study was approved by our institutional review board. A total 43 patients were included, all with pathologic diagnosis of glioblastoma with known MGMT methylation and 1p/19q deletion statuses. We divided these patients into long-term (≥ 60 months, n = 7) and short-term (< 60 months, n = 36) survivors, then compared surgical extent, molecular status, and rCBV parameters between the two groups using Fisher's exact test or Mann-Whitney test. The rCBV parameters were analyzed according to the presence of MGMT methylation and 1p/19q deletions. We investigated the relationship between the mean rCBV and overall survival using linear correlation. Multivariable linear regression was performed in order to find the variables related to overall survival. RESULTS: Long-term survivors (100% [7 of 7]) demonstrated a greater percentage of gross total or near total resection than short-term survivors (54.5% [18 of 33]). A higher prevalence of 1p/19q deletions was also noted among the long-term survivors (42.9% [3 of 7]) than the short-term survivors (0.0% [0 of 36]). The rCBV parameters did not differ between the long-term and short-term survivors. The rCBV values were marginally lower in patients with MGMT methylation and 1p/19q deletions. Despite no correlation found between overall survival and rCBV in the whole group, the short-term survivor group showed negative correlation (R2 = 0.181, P = 0.025). Multivariable linear regression revealed that surgical extent and 1p/19q deletions, but not rCBV values, were associated with prolonged overall survival. CONCLUSION: While preoperative rCBV and 1p/19q deletion status are related to each other, only surgical extent and the presence of 1p/19q deletion in GBM patients may predict long-term survival.

Comparative study of arterial spin labeling and dynamic susceptibility contrast of solitary brain metastasis at 3.0T MR / 实用放射学杂志

Objective To evaluate the perfusion findings of solitary brain metastasis using MR arterial spin labeling (ASL)imaging,and make a comparison with dynamic susceptibility contrast (DSC)imaging.Methods Twenty-three patients with pathologically proven solitary brain metastasis from lung cancer underwent ASL and DSC imaging.The ASL cerebral blood flow (CBF),DSC regional CBF (rCBF)and DSC regional cerebral blood volume (rCBV)were measured and compared between the tumor and the contralateral brain parenchyma.Pearson correlation test was performed to assess the relations between ASL and DSC measurements.Results Brain metastasis showed ring-like hyper-perfusion on ASL and DSC mappings.ASL CBF values of the tumor and the contralateral brain parenchyma were(54.872±21.131)mL·min-1·100 g-1and (21.109±4.788)mL·min-1·100 g-1,respectively (P<0.01).DSC rCBF values of the tumor and the contralateral brain parenchyma were (1.094 8±0.309 3)mL·min-1·100 g-1and (0.495 7±0.154 1)mL· min-1·100 g-1,respectively (P<0.01).DSC rCBV values of the tumor and the contralateral brain parenchyma were (1.753 1±0.545 5)mL/100 g and (0.729 9±0.215 8)mL/100 g,respectively (P<0.01).There was a strong correlation between ASL CBF and DSC rCBF (r=0.898,P<0.01),and there was no correlation between ASL CBF and DSC rCBV.Conclusion ASL can evaluate the CBF of brain metastasis as DSC dose. It requires no contrast agent administration and can be used in daily clinical practice.

Differentiation between Glioblastoma and Primary Central Nervous System Lymphoma Using Dynamic Susceptibility Contrast-Enhanced Perfusion MR Imaging: Comparison Study of the Manual versus Semiautomatic Segmentation Method

BACKGROUND: Normalized cerebral blood volume (nCBV) can be measured using manual or semiautomatic segmentation method. However, the difference in diagnostic performance on brain tumor differentiation between differently measured nCBV has not been evaluated. PURPOSE: To compare the diagnostic performance of manually obtained nCBV to that of semiautomatically obtained nCBV on glioblastoma (GBM) and primary central nervous system lymphoma (PCNSL) differentiation. MATERIALS AND METHODS: Histopathologically confirmed forty GBM and eleven PCNSL patients underwent 3T MR imaging with dynamic susceptibility contrast-enhanced perfusion MR imaging before any treatment or biopsy. Based on the contrast-enhanced T1-weighted imaging, the mean nCBV (mCBV) was measured using the manual method (manual mCBV), random regions of interest (ROIs) placement by the observer, or the semiautomatic segmentation method (semiautomatic mCBV). The volume of enhancing portion of the tumor was also measured during semiautomatic segmentation process. T-test, ROC curve analysis, Fisher's exact test and multivariate regression analysis were performed to compare the value and evaluate the diagnostic performance of each parameter. RESULTS: GBM showed a higher enhancing volume (P = 0.0307), a higher manual mCBV (P = 0.018) and a higher semiautomatic mCBV (P = 0.0111) than that of the PCNSL. Semiautomatic mCBV had the highest value (0.815) for the area under the curve (AUC), however, the AUCs of the three parameters were not significantly different from each other. The semiautomatic mCBV was the best independent predictor for the GBM and PCNSL differential diagnosis according to the stepwise multiple regression analysis. CONCLUSION: We found that the semiautomatic mCBV could be a better predictor than the manual mCBV for the GBM and PCNSL differentiation. We believe that the semiautomatic segmentation method can contribute to the advancement of perfusion based brain tumor evaluation.

The value of IVIM imaging and DSC perfusion imaging in cerebral astrocytoma grading / 实用放射学杂志

Objective To investigate the value of MR intravoxel incoherent motion (IVIM)imaging and dynamic susceptibility contrast-enhanced(DSC)perfusion imaging in astrocytoma grading.Methods 22 patients with high grade astrocytoma and 28 patients with low grade astrocytoma underwent conventional MRI and IVIM,DSC scanning before operation.Parameters of IVIM included standard diffusion coefficient(ADCstandard ),slow diffusion coefficient(D),fast diffusion coefficient(D? ),fractional perfusion-related volume (f)values,and parameters of DSC included relative blood volume(rCBV),relative blood flow(rCBF)values of tumor solid part were measured quantitatively.The values between the two groups were compared by two samples t-test.By using ROC curve to evaluate the diagnostic efficacy of using IVIM and DSC alone or jointly.Results The ADCstandard ,D,rCBV,rCBF values of tumor solid part had significant differences between the groups(P<0.01).The D? and f values were no significant differences (P=0.130,P=0.379).The area under the ROC curve of the values showed that ADCstandard (0.823),D(0.854),rCBV(0.858),rCBF(0.871),D+rCBV(0.952),D+rCBF(0.953).Conclusion The D,rCBV,rCBF values are helpful to determine the grade of astrocytomas.The use of IVIM in combination with DSC may improve the diagnostic accuracy of astrocytoma grading.

Comparative study of DSC-PWI and 3D-ASL in ischemic stroke patients / 华中科技大学学报（医学）（英德文版）

The purpose of this study was to quantitatively analyze the relationship between three dimensional arterial spin labeling (3D-ASL) and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI) in ischemic stroke patients. Thirty patients with ischemic stroke were included in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging (DWI), magnetic resonance angiography (MRA), 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest (ROIs) were drawn on the cerebral blood flow (CBF) maps (derived from ASL) and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time (MTT) were calculated. The relationships between ASL and DSC parameters were analyzed using Pearson's correlation analysis. Receiver operative characteristic (ROC) curves were performed to define the thresholds of relative value of ASL-CBF (rASL) that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients (R) values being 0.611 (P<0.001) and-0.610 (P<0.001) respectively. ROC curves demonstrated that when rASL ≤0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF<0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL ≤0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT>1.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters (DSC-CBF and MTT) in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. If rASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.

Perfusion Magnetic Resonance Imaging: A Comprehensive Update on Principles and Techniques

Perfusion is a fundamental biological function that refers to the delivery of oxygen and nutrients to tissue by means of blood flow. Perfusion MRI is sensitive to microvasculature and has been applied in a wide variety of clinical applications, including the classification of tumors, identification of stroke regions, and characterization of other diseases. Perfusion MRI techniques are classified with or without using an exogenous contrast agent. Bolus methods, with injections of a contrast agent, provide better sensitivity with higher spatial resolution, and are therefore more widely used in clinical applications. However, arterial spin-labeling methods provide a unique opportunity to measure cerebral blood flow without requiring an exogenous contrast agent and have better accuracy for quantification. Importantly, MRI-based perfusion measurements are minimally invasive overall, and do not use any radiation and radioisotopes. In this review, we describe the principles and techniques of perfusion MRI. This review summarizes comprehensive updated knowledge on the physical principles and techniques of perfusion MRI.

Preliminary study of 3D arterial spin labeling in diagnosis of ischemic cerebrovascular disease / 国际生物医学工程杂志

Objective To investigate the feasibility and clinical application value of 3D arterial spin labeling (3DASL) technique in diagnosis of ischemic cerebrovascular disease.Methods Experiment 1:Controlgroup (n=30) and brain infarction group (n=20) were established.All patients were routinely examined including 3DASL and dynamic susceptibility contrast (DSC) enhanced series.The analysis of the control group was performed using signal intensity measurement in three paired regions of interest (ROI) which were selected in left hemisphere centrum semiovale and the opposite hemisphere mirror regions respectively.The ROIs of brain infarction group were selected in the lesion areas and their mirror region.The cerebral blood flow (CBF) of each ROI was measured with 3DASL and DSC respectively.The CBF ratio to each ROI and its mirror ROI were calculated.Data were compared using paired-t test.Experiment 2:Acute cerebral infarction (n=30) and transient ischemic attack (TIA) group (n=30) were established.All patients were routinely examined including 3DASL and diffusion weighted imaging (DWI).The positive rate and the area of the lesions were calculated respectively with 3DASL and DWI and compared.Results Experiment 1:Both the control and brain infarction group demonstrated agreement between 3DASL and DSC.The CBF ratios of the control group were 1.02±0.18 and 1.06±0.24 respectively and revealed no statistically significant between that of 3DASL and DSC (P＞0.05).The CBF ratios of brain infarction group were 0.50±0.12 and 0.48±0.18 respectively,and also revealed no statistically significant between two methods (P＞0.05).Experiment 2:The positive rate of acute cerebral infarction were 100％ with both DWI and 3DASL.The areas of the lesion detected by both methods were:SDwI＜S3DASL,n=22; SDWI ≈-S3DASL,n=8; SDWI＞S3DASL,n=0.The positive rate of TIA by DWI was 0％,and 70％ by 3DASL.Conclusion The noninvasive,safe and repeatable 3DASL technique is almost as sensitive as DSC in the measurement of CBF.However,and it is more sensitive than DWI in diagnosis of TIA.Combining 3DASL and DWI will be helpful in early diagnosis of TIA,finding ischemic penumbra and estimating the blood perfusion of ischemic cerebrovascular disease.

Application of Dynamic Susceptibility Contrast-Enhanced MR Imaging in Evaluation of Brain Tumor after Operation / 实用放射学杂志

Objective To evaluate the value of dynamic susceptibility contrast-enhanced MR imaging (DSC)in evaluation of brain tumor after operation.Methods 41 cases with brain tumors verified histologically,including 8 cases of high-grade gliomas,16 of low-grade gliomas,7 of metastases and 10 of meningiomas underwent DSC examination.All the cases at 3.0T MR unit.All primitive data were sent to ADW4.3 workstation for post-processing.The mean maximal rCBV and rCBF ratios of tumors,1 cm and 2 cm regions of peri-tumor were obtained respectively.The relativity of MR perfusion parameters(rCBV and rCBF)between diferent tumors were statistically evaluated by using Pearson correlative analysis.Results In the　solid region of tumors,rCBV and rCBF were statistically significant differences (P<0.05)between low-grade gliomas and the other three groups of tumors; in 1 cm region of peri-tumor between high-grade gliomas and the other three groups,and between low-grade gliomas and metastases,between the solid region and both regions of 1 cm and 2 cm peri-tumors at the same tumor were all of statistically significant differences(P<0.05),between 1 cm and 2 cm region of peri-tumors at high-grade gliomas and metastases,the rCBV and rCBF were also of statistically significant differences.Pearson correlative analysis showed that there were significant positive correlations between the mean maximal rCBV and rCBF　ratios at the same region in the same tumor's group.Conclusion DSC is very valuable in evaluation of the histopathological grade and the differentiation of brain tumor.