Intratumoral Susceptibility Signal Intensity Research Articles

Improvement grading brain glioma using T2 relaxation times and susceptibility-weighted images in MRI

Developing a new non-invasive, and accurate method for glioma grading for glioma treatment and management is very important. Magnetic resonance imaging (MRI) has many applications in the field of neuroimaging. The study aims to create a precise way to improve glioma grading using different MRI image weights. There were 47 participants in this study. A 1.5 T MRI scanner acquired T2 multi-echoes (T2 ME) with eight echoes for T2 maps reconstruction, Susceptibility-Weighted Imaging (SWI), and T1 post-contrast. T2 maps were reconstructed from T2 ME data using homemade MATLAB code. To compare T2 relaxation times and intratumoral susceptibility signal intensity (ITSS) between the high-grade gliomas (HGGs) and low-grade gliomas (LGGs) and other analyses, we used SPSS software. There was a significant difference in T2 relaxation times and ITSS between the HGGs and LGGs. The average T2 relaxation times in HGGs and LGGs were 0.12 and 0.16 s, respectively. Further analysis showed that the ITSS in HGGs is significantly greater than in LGGs. There was a significant negative correlation between T2 relaxation times and ITSS in gliomas. It is interesting to note that combining T2 relaxation times, ITSS, and tumor enhancement status data with a multivariate binary logistic regression model can increase the area under the curve (AUC) to 0.94 for glioma-grade classification. We recommended the clinical use of combined T2 maps, SWI, and T1 post-contrast image-weights data with a multivariate binary logistic regression model for improving glioma grading.

Grading of IDH-mutant astrocytoma using diffusion, susceptibility and perfusion-weighted imaging

BackgroundThe accurate grading of IDH-mutant astrocytoma is essential to make therapeutic strategies and assess the prognosis of patients. The purpose of this study was to investigate the usefulness of DWI, SWI and DSC-PWI in grading IDH-mutant astrocytoma.MethodsOne hundred and seven patients with IDH-mutant astrocytoma who underwent DWI, SWI and DSC-PWI were retrospectively reviewed. Minimum apparent diffusion coefficient (ADCmin), intratumoral susceptibility signal intensity(ITSS) and maximum relative cerebral blood volume (rCBVmax) values were assessed. ADCmin, ITSS and rCBVmax values were compared between grade 2 vs. grade 3, grade 3 vs. grade 4 and grade 2 + 3 vs. grade 4 tumors. Logistic regression, tenfold cross-validation,and receiver operating characteristic (ROC) curve analyses were used to assess their diagnostic performances.ResultsGrade 4 IDH-mutant astrocytomas showed significantly lower ADCmin and higher rCBVmax as compared to grade 3 tumors (adjusted P < 0.001). IDH-mutant grade 3 astrocytomas showed significantly lower ITSS levels as compared with grade 4 tumors (adjusted P < 0.001). ITSS levels between IDH-mutant grade 2 and grade 3 astrocytomas were significantly different (adjusted P = 0.002). Combined the ADCmin, ITSS and rCBVmax resulted in the highest AUC for differentiation grade 2 and grade 3 tumors from grade 4 tumors.ConclusionADCmin, rCBVmax and ITSS can be used for grading the IDH-mutant astrocytomas. The combination of ADCmin, ITSS and rCBVmax could improve the diagnostic performance in grading of IDH-mutant astrocytoma.

A comparative study of multimodal magnetic resonance in the differential diagnosis of acquired immune deficiency syndrome related primary central nervous system lymphoma and infection

BackgroundPatients with acquired immune deficiency syndrome (AIDS) often suffer from opportunistic infections and related primary central nervous system lymphoma (AR-PCNSL). Both diseases showed multiple ring enhancement lesions in conventional magnetic resonance (MR). It is very difficult to make the differential diagnosis. We aimed to investigate whether multimodal MR (diffusion weighted imaging (DWI)/ apparent diffusion coefficient (ADC), 3D pseudo-continuous arterial spin labeling (3D-pCASL) and susceptibility-weighted imaging (SWI)) combined with conventional MR can differentiate AR-PCNSL from infections.MethodsThis was a prospective study. We recruited 19 AIDS patients who were divided into AR-PCNSL group (9 cases) and infection group (10 cases) by pathological results. We analyzed whether there was statistical (Fisher’s method) difference in multimodal MR between the two groups. We analyzed whether multimodal MR combined with conventional MR could improve the diagnosis of AR-PCNSL.ResultsThe lesions were more likely involved the paraventricular (0.020) and corpus callosum (0.033) in AR-PCNSL group in conventional MR. In multimodal MR, AR-PCNSL group showed low ADC value, with p values of 0.001. Infection group more inclined to high ADC value, with p was 0.003. In multimodal MR, AR-PCNSL group had more low signal intensity (grade 2–3) in the degree of intratumoral susceptibility signal intensity in SWI (SWI-ITSS), with p values of 0.001. The sensitivity, specificity of conventional MR in the diagnosis of AR-PCNSL was 88.9 and 70.0%. The conventional MR sequence combined with DWI/ADC sequence in the diagnosis of AR-PCNSL had a sensitivity of 100.0%, and a specificity of 60.0%. The sensitivity and specificity of the conventional MR sequence combined with the SWI-ITSS sequence in the diagnosis of AR-PCNSL were 100 and 70.0%. The conventional MR combined with ADC or SWI-ITSS improved the diagnosis of AR-PCNSL.ConclusionMultimodal MR could distinguish AR-PCNSL from infectious lesions. The multimodal MR (DWI/ADC or SWI-ITSS) combined with conventional MR could improve the diagnosis of AR-PCNSL. The ADC value should be attached importance in clinical work. When distinguishing AR-PCNSL from toxoplasmosis or tuberculoma, SWI should be used to obtain a correct diagnosis.

Added value of susceptibility-weighted imaging to diffusion-weighted imaging in the characterization of parotid gland tumors.

To assess the added value of susceptibility-weighted imaging (SWI) to diffusion-weighted imaging (DWI) in the characterization of parotid gland tumors. Seventy-eight patients with pathologically confirmed parotid gland tumors, who underwent DWI and SWI for pre-surgery evaluation, were enrolled. Apparent diffusion coefficient (ADC) and degree of intratumoral susceptibility signal intensity (ITSS) were measured and compared between benign and malignant groups, and among pleomorphic adenoma (PA), Warthin tumor (WT) and malignant tumor (MT). Independent sample t test, one-way analysis of variance and receiver operating characteristic curve analysis were used for statistical analyses. Benign parotid gland tumor showed a significantly higher mean ADC value than malignant tumors (0.836 ± 0.350 vs 0.592 ± 0.163, p = 0.001). Setting an average ADC value of 0.679 as the cut-off value, optimal differentiating performance could be obtained (AUC, 0.700; sensitivity, 62.69%; specificity, 81.82%) for differentiating malignant from benign tumors. PA showed significantly higher mean ADC and less ITSS than WT (ADC, p < 0.001; ITSS, p = 0.033) and MT (ADC, p < 0.001; ITSS, p = 0.024), while the difference between WT and MT was not significant (ADC, p = 0.826; ITSS, p = 0.539). After integration with ITSS, the diagnostic performance of ADC was improved for differentiating PA from WT (AUC 0.921 vs 0.873) and from MT (AUC 0.906 vs 0.882). SWI could provide added information to DWI and serve as a supplementary imaging marker for the characterization of parotid gland tumors.

Role of susceptibility-weighted imaging and intratumoral susceptibility signals in grading and differentiating pediatric brain tumors at 1.5 T: a preliminary study.

Susceptibility-weighted imaging (SWI) is useful for glioma grading and discriminating between brain tumor categories in adults, but its diagnostic value for pediatric brain tumors is unclear. Here we evaluated the usefulness of SWI for pediatric tumor grading and differentiation by assessing intratumoral susceptibility signal intensity (ITSS). We retrospectively enrolled 96 children with histopathologically diagnosed brain tumors, who underwent routine brain MRI exam with SWI (1.5T scanner). Each tumor was assigned an ITSS score by a radiology resident and an experienced neuroradiologist, and subsequently by consensus. Statistical analyses were performed to differentiate between low-grade (LG) and high-grade (HG) tumors, histological categories, and tumor locations. Inter-reader agreement was assessed using Cohen's kappa (κ). The interobserver agreement was 0.844 (0.953 between first reader and consensus, and 0.890 between second reader and consensus). Among all tumors, we found a statistically significant difference between LG and HG for ITSS scores of 0 and 2 (p = 0.002). This correlation was weaker among astrocytomas alone, and became significant when considering only off-midline astrocytomas (p = 0.05). Scores of 0 and 2 were a strong discriminating factor (p = 0.001) for astrocytomas (score 0) and for embryonal, choroid plexus, germ-cell, pineal, and ependymoma tumors (score 2). No medulloblastoma showed a score of 0. Our preliminary ITTS results in pediatric brain tumors somewhat differed from those obtained in adult populations. These findings highlight the potential valuable role of ITSS for tumor grading and discriminating between some tumor categories in the pediatric population.

Differentiating intracranial solitary fibrous tumor/hemangiopericytoma from meningioma using diffusion-weighted imaging and susceptibility-weighted imaging.

Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) and meningioma are difficult to distinguish owing to their overlapping imaging manifestation on routine magnetic resonance imaging. The purpose of this study was to assess whether SFT/HPC can be differentiated from meningioma with diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI). We retrospectively reviewed DWI, SWI, conventreional MR, and CT imaging features of 16 patients with SFT/HPC and 96 patients with meningioma. The apparent diffusion coefficient (ADC) value, normalized ADC (nADC) value, and degree of intratumoral susceptibility signal intensity (ITSS) were compared between SFT/HPCs and meningiomas using two-sample t tests, and among SFT/HPCs, low-grade and high-grade meningioma were tested using one-way analysis of variance (ANOVA). Receiver operating characteristic (ROC) curve and logistic regression analyses were performed to determine the differentiation capacity. The ADC value, nADC value, and the degree of ITSS in SFT/HPC were significantly higher than those in low-grade and high-grade meningiomas (all p < 0.05). The threshold value of > 1.15 for nADC provided 75.00% sensitivity and 60.42% specificity for differentiating SFT/HPC from meningioma. Compared with nADC, the degree of ITSS had a moderate sensitivity (62.50%) and a higher specificity (85.42%) using the threshold value of > 1.00. Furthermore, combining DWI and SWI can achieve a relatively high differentiation capacity with a sensitivity of 81.25% and specificity of 78.12%. The nADC ratios and ITSS are useful for differentiating SFT/HPC from meningioma. Combining ITSS and nADC value appears to be a promising option for differential diagnosis.

Contribution of susceptibility- and diffusion-weighted magnetic resonance imaging for grading gliomas.

The aim of the present study was to assess the value of susceptibility-weighted imaging (SWI) and diffusion-weighted imaging (DWI) in the grading of gliomas and to evaluate the correlation between these quantitative parameters derived from SWI and DWI. A total of 49 patients with glioma were assessed by DWI and SWI. The evaluation included the ratio of apparent diffuse coefficient values between the solid portion of tumors and contralateral normal white matter (rADC) and the degree of intratumoral susceptibility signal intensity (ITSS) within tumors. Receiver operating characteristic curve (ROC) analyses were performed and the area under the ROC curve was calculated to compare the diagnostic performance, determine optimum thresholds for tumor grading, and calculate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for identifying high-grade gliomas. The correlation between DWI- and SWI-derived parameters was also evaluated. The rADC and the degrees of ITSS within tumors were significantly higher in high-grade gliomas than those in low-grade gliomas. ROC curve analysis indicated that the rADC was a better index for grading gliomas than the ITSS degree. Statistical analysis demonstrated a threshold value of 1.497 for rADC to provide a sensitivity, specificity, PPV and NPV of 86.2, 85.0, 89.3 and 81.0%, respectively, for determining high-grade gliomas. A degree of ITSS of 1.5 was defined as the threshold to identify high-grade gliomas and sensitivity, specificity, PPV and NPV of 82.8, 75.0, 82.8 and 75.0% were obtained, respectively. Furthermore, a moderate inverse correlation between rADC and the ITSS degree was revealed. Combination of SWI with DWI may provide valuable information for glioma grading.

Differentiation of grade II/III and grade IV glioma by combining "T1 contrast-enhanced brain perfusion imaging" and susceptibility-weighted quantitative imaging.

MRI is a useful method for discriminating low- and high-grade glioma using perfusion MRI and susceptibility-weighted imaging (SWI). The purpose of this study is to evaluate the usefulness of T1-perfusion MRI and SWI in discriminating among grade II, III, and IV gliomas. T1-perfusion MRI was used to measure relative cerebral blood volume (rCBV) in 129 patients with glioma (70 grade IV, 33 grade III, and 26 grade II tumors). SWI was also used to measure the intratumoral susceptibility signal intensity (ITSS) scores for each tumor in these patients. rCBV and ITSS values were compared to seek differences between grade II vs. grade III, grade III vs. grade IV, and grade III+II vs. grade IV tumors. Significant differences in rCBV values of the three grades of the tumors were noted and pairwise comparisons showed significantly higher rCBV values in grade IV tumors as compared to grade III tumors, and similarly increased rCBV was seen in the grade III tumors as compared to grade II tumors (p<0.001). Grade IV gliomas showed significantly higher ITSS scores on SWI as compared to grade III tumors (p<0.001) whereas insignificant difference was seen on comparing ITSS scores of grade III with grade II tumors. Combining the rCBV and ITSS resulted in significant improvement in the discrimination of grade III from grade IV tumors. The combination of rCBV values derived from T1-perfusion MRI and SWI derived ITSS scores improves the diagnostic accuracy for discrimination of grade III from grade IV gliomas.

Diffusion-weighted MRI combined with susceptibility-weighted MRI: added diagnostic value for four common lateral ventricular tumors

Background Diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) are reliable imaging modalities for brain tumors. However, the role of DWI and SWI in the diagnosis of common lateral ventricular tumors has not been systematically evaluated. Purpose To evaluate the diagnostic performance of DWI and SWI in common lateral ventricular tumors. Material and Methods Fifty-two patients with histopathologically confirmed lateral ventricular tumors were included in this study (18 with central neurocytomas, nine with ependymomas, seven with high-grade gliomas, and 18 with meningiomas). The relative minimum apparent diffusion coefficient (rADCmin) and relative average apparent diffusion coefficient (rADCave) measured by DWI and the intratumoral susceptibility signal intensity (ITSS) of hemorrhage acquired by SWI were calculated. These quantitative parameters were evaluated using the Mann-Whitney U test, receiver operating characteristic curve, and logistic regression analyses. Results The rADCmin and rADCave ratios of central neurocytomas were significantly lower than those of the other neoplasms. The rADCmin and rADCave ratios of ependymomas and the rADCave ratio of high-grade gliomas were significantly higher than those of meningiomas. The ITSS score of meningiomas was significantly lower than those of the other tumors, while the score of central neurocytomas was obviously lower than those of ependymomas and high-grade gliomas. The combination of the rADC ratio with the ITSS showed no significant difference, except in discriminating between meningiomas and high-grade glioma-ependymomas. Conclusion The rADC ratios and ITSS may be useful for differentiating common lateral ventricular tumors. The diagnostic performance may be improved with the use of the rADC ratios and ITSS scores.

Study of susceptibility weighted imaging on MR and pathologic findings to distinguish benign or malignant soft tissue tumor

Objective: To explore the diagnostic performance of susceptibility weighted imaging (SWI)in distinguishing benign or malignant soft tissue tumor, and to study pathological observation. Methods: Sixty-eight patients with soft tissue tumor, who received no previous treatment or invasive examination, received routine preoperative MRI examination and SWI scanning. The graduation and distribution of intratumoral susceptibility signal intensity(ITSS) and proportion of tumor volume were observed.The pathological results were also included for comparative analysis. Results: Fourty of 68 patients were benign and 28 were malignant. 72.5% (29/40) patients with benign soft tissue tumors were ITSS grade 1 and ITSS grade 3 (hemangioma). 89.3%(25/28) patients with malignant soft tissue tumors were ITSS grade 2 and ITSS grade 3. The difference was statistically significant (P<0.01). The distribution of ITSS in patients with benign soft tissue tumors was dominated by peripheral distribution and diffuse distribution (hemangioma), accounting for 90.0% (36/40). The distribution of ITSS in patients with malignant soft tissue tumors mainly distributed in the central region, accounting for 78.6% (22 /28). The difference was statistically significant (P<0.01). The proportion of tumor volume occupied by ITSS in benign soft tissue tumors was <1/3 and> 2/3 (hemangioma), accounting for 90.0% (36/40). The volume of malignant soft tissue tumors were predominantly <1/3 , accounting for 82.1% (23/28). The difference was statistically significant (P<0.01). Conclusion: SWI is sensitive in displaying the vein and blood metabolites in soft tissue lesions, which is helpful for the differential diagnosis of benign and malignant tumors in soft tissue.

Use of Ultrasmall Superparamagnetic Iron Oxide Enhanced Susceptibility Weighted Imaging and Mean Vessel Density Imaging to Monitor Antiangiogenic Effects of Sorafenib on Experimental Hepatocellular Carcinoma.

We investigated effectiveness of ultrasmall superparamagnetic iron oxide enhanced susceptibility weighted imaging (USPIO-enhanced SWI) and mean vessel density imaging (Q) in monitoring antiangiogenic effects of Sorafenib on orthotopic hepatocellular carcinoma (HCC). Thirty-five HCC xenografts were established. USPIO-enhanced SWI and Q were performed on a 1.5 T MR scanner at baseline, 7, 14, and 21 days after Sorafenib treatment. Intratumoral susceptibility signal intensity (ITSS) and Q were serially measured and compared between the treated (n = 15) and control groups (n = 15). Both ITSS and Q were significantly lower in the treated group at each time point (P < 0.05). Measurements in the treated group showed that ITSS persisted at 7 days (P = 0.669) and increased at 14 and 21 days (P < 0.05), while Q significantly declined at 7 days (P = 0.028) and gradually increased at 14 and 21 days. In the treated group, significant correlation was found between Q and histologic microvessel density (MVD) (r = 0.753, P < 0.001), and ITSS correlated well with MVD (r = 0.742, P = 0.002) after excluding the data from baseline. This study demonstrated that USPIO-enhanced SWI and Q could provide novel biomarkers for evaluating antiangiogenic effects of Sorafenib on HCC.

Contrast-enhanced susceptibility weighted imaging with ultrasmall superparamagnetic iron oxide improves the detection of tumor vascularity in a hepatocellular carcinoma nude mouse model.

To evaluate the effectiveness of contrast-enhanced susceptibility-weighted imaging with ultrasmall superparamagnetic iron oxide (USPIO-enhanced SWI) in the assessment of intratumoral vascularity in hepatocellular carcinoma (HCC). Orthotopic xenograft HCC nude mouse models were established first and magnetic resonance imaging (MRI) examinations were performed on a 1.5T MR scanner 28 days later. Three groups of mice, 10 in each, were imaged using unenhanced and USPIO-enhanced SWI at doses of 4, 8, and 12 mg Fe/kg. Intratumoral susceptibility signal intensity (ITSS) was scored. ITSS-to-tumor contrast-to-noise ratio (ITSST-CNR) was measured. These measurements were compared between unenhanced and USPIO-enhanced SWI at each dose and differences in the measurements between different dose groups were estimated. Correlation between ITSS and tumor microvessel density (MVD) was analyzed. Compared with unenhanced SWI, significantly higher ITSS was identified on USPIO-enhanced SWI at doses of 8 mg Fe/kg (Z = -2.000, P = 0.046) and 12 mg Fe/kg (Z = -2.333, P = 0.020). Significantly higher ITSST-CNR was found on USPIO-enhanced SWI than that on unenhanced SWI (P < 0.05). Significantly higher ITSST-CNR at a dose of 8 mg Fe/kg was observed than that at 4 mg Fe/kg (Z = -3.326, P = 0.001). Positive correlation between ITSS on USPIO-enhanced SWI at a dose of 8 mg Fe/kg and tumor MVD was demonstrated (r = 0.817, P = 0.004). USPIO-enhanced SWI at a dose of 8 mg Fe/kg greatly improves the detection of intratumoral vascularity in a xenograft HCC model. J. Magn. Reson. Imaging 2016;44:288-295.

Prediction of nuclear grade of clear cell renal cell carcinoma with MRI: intratumoral susceptibility signal intensity versus necrosis

End-stage renal disease and dialysis patients have a higher incidence of renal cell carcinoma (RCC) than the general population. Preoperatively evaluating the biological behavior of RCC plays an important role in treatment decision-making. Susceptibility-weighted imaging (SWI) can visualize the distribution of microvenous structures and hemorrhage without contrast materials. To evaluate the feasibility of SWI in grading clear cell RCCs (CRCC) and compare the ability of SWI and necrosis for grading CRCCs. Retrospective reviews of 35 patients with pathologically-proven CRCCs were performed. All patients underwent both conventional magnetic resonance imaging (MRI) and SWI examinations. The morphology of the intratumoral susceptibility signal intensities (ITSS) was classified into hemorrhage and microvessels. The differences of ITSSs on SWI and necrosis between low- and high-grade CRCCs were assessed. The diagnostic values of ITSSs and necrosis in differentiating low- from high-grade CRCCs were compared by receiver-operating characteristics. ITSSs were seen in 31 of 35 patients. No ITSSs were seen in four patients with low-grade CRCCs. Mean scores of ITSSs on SWI were significantly lower for low-grade CRCCs (1.24 ± 0.72) than that for the high-grade CRCCs (2.70 ± 0.48). No significant necrosis was seen in 10 patients with low-grade CRCCs. There was a significant difference of the presence of intratumoral necrosis between low- and high-grade CRCCs. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were for ITSSs: 70%, 100%, 100%, and 89.3%, respectively; for necrosis: 100%, 40%, 40%, and 100%. SWI can evaluate ITSSs without contrast materials and can be an alternative to grading CRCCs preoperatively for some special patients.

Combined value of susceptibility-weighted and perfusion-weighted imaging in assessing who grade for brain astrocytomas.

To assess the value of combining susceptibility-weighted imaging (SWI) and dynamic susceptibility weighted contrast-enhanced (DSC) perfusion-weighted MRI (PWI) in assessing World Health Organization (WHO)grade for brain astrocytoma . A total of 94 patients with pathologically confirmed astrocytomas underwent SWI and DSC scans. The evaluation included intratumoral susceptibility signal intensity (ITSS) and relative cerebral blood volume (rCBV) max. The receiver operating characteristic curve (ROC) was used to assess the efficacy of combining two sequences in astrocytoma grading. ITSS within astrocytomas showed significant correlations with rCBV max (r ¼ 0.72; P < 0.01) and with tumor grades (r ¼ 0.92; P < 0.01), and there was also a significant correlation between rCBV and tumor grade (r= 0.77; P < 0.001). The area under the ROC, SWI, PWI,SWI, and PWI, in differentiation of the grades II and III astrocytomas were 0.995, 0.942, and 1.000, respectively;identifying grades III and IV were 0.773, 0.919, and 0.978, respectively; and identifying high and low-grade astrocytomas were 0.999, 0.992, 1.000, respectively. ITSS was useful for assessing the WHO tumor grade in this cohort of patients with astrocytoma.The combination of SWI and PWI may improve the diagnostic accuracy of astrocytoma grading.

Assessment of Intratumoral Micromorphology for Patients with Clear Cell Renal Cell Carcinoma Using Susceptibility-Weighted Imaging

BackgroundMultiple treatment options exist for the management of renal cell carcinomas. Preoperative evaluation of clear cell renal cell carcinoma (CRCC) grades is important for deciding upon the appropriate method of therapy. We hypothesize that susceptibility weighted imaging (SWI) is sensitive enough to detect intratumoral microvessles and microbleeding in renal cell carcinoma, which can be used to grade CRCC.Material and MethodsRetrospective reviews of 37 patients with pathologically proven CRCCs were evaluated. All patients underwent SWI examinations. The characteristics of intratumoral susceptibility signal intensity (ITSS) includes the likelihood of the presence of ITSS, morphology of ITSS, dominant structure of ITSS and ratio of ITSS area to tumor area, which were all assessed on SWI. The results were compared using the nonparametric Mann-Whitney test.ResultsITSS was seen in all patients except 4 patients with low-grade CRCCs. There was no significant difference between low and high-grade CRCCs when looking at the likelihood of the presence of ITSS. There was a significant difference in the mean score of dominant structures between low and high-grade CRCCs. Specifically, more dominant vascular structures and less hemorrhage were seen in low-grade tumors (2.15±1.05) compared to high-grade tumors (1.27±0.47) (P<0.005). The ratio of ITSS area to tumor area was also significantly higher for the high-grade group (1.55±0.52) than that for the low-grade group (0.88±0.43) on SWI (P<0.005).ConclusionSWI is useful for grading CRCCs.

Combined value of susceptibility weighted imaging and dynamic susceptibility-weighted contrast-enhanced MR perfusion-weighted imaging in brain astrocytoma grading

Objective To assess the value of combination of susceptibility weighted imaging (SWI)and dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion-weighted magnetic resonance imaging in astrocytoma grading.Methods SWI and DSC scans were performed in 82 patients with pathologically confirmed astrocytoma.The patient group consisted of grade Ⅱ (15),grade Ⅲ (10),and grade Ⅳ (57).The intratumoral susceptibility signal intensity (ITSS) and relative cerebral blood volume (rCBV) max were used to determine the grade of astrocytomas by Kruskal Wallis test,Welch test,Spearman correlation coefficients,Pearson correlation coefficients,and receiver operating characteristic curve (ROC)statistic methods.Results There were no ITSS in 14 cases of low-grade astrocytomas,the degree of ITSS were grade 1 to 3 in anaplastic astrocytomas,the degree of ITSS were grade 3 in all of the glioblastomas,the degree of ITSS were significant difference in all grades (H =71.96,P ＜ 0.01).rCBV max in grade Ⅱ,grade Ⅲ and grade Ⅳ astrocytomas were 1.26 ± 0.42,3.59 ± 2.09 and 8.34 ± 1.16 respectively,rCBV max were significant difference in all grades (F' =681.72,P ＜ 0.01).ITSS showed significant correlation with rCBV max (r =0.72,P ＜0.01) and tumor grades (r =0.89,P ＜0.01),and rCBV and tumor grades showed significant correlation (r =0.78,P ＜ 0.01).Area under the ROC curve application SWI,DSC,SWI and DSC in differentiation of the grade Ⅱ and grade Ⅲ astrocytomas were 0.99,0.93,1.00,differentiate grade Ⅲ from grade Ⅳ were 0.70,0.94,0.94,and differentiate high-grade from low-grade astrocytomas were 1.00,0.99,1.00.Conclusions ITSS is helpful to determine the grade of astrocytomas.The use of SWI in combination with DSC may improve the diagnostic accuracy of astrocytoma grading. Key words: Astrocytoma; Magnetic resonance imaging; Perfusion ; Diagnosis, differential

Precontrast and postcontrast susceptibility-weighted imaging in the assessment of intracranial brain neoplasms at 1.5 T

The goal of this study was to estimate pre- and post-gadolinium-enhanced high-spatial resolution susceptibility-weighted imaging (SWI) in patients with brain neoplasms. A total of 17 patients (8 women, 9 men) with brain neoplasms participated in this study. In addition to conventional magnetic resonance imaging, pre- and post-gadolinium-enhanced SWI was performed. The contrast-to-noise ratio (CNR) and major diameters of the brain tumor were measured for quantitative analyses, and intratumoral susceptibility signal intensity (ITSS) was graded for semiquantitative analysis. Both bright and dark enhancement were observed at the pathological lesion on postcontrast SWI. Some postcontrast SWI results suggested leakage of contrast material due to breakdown of the blood-brain barrier. There were no statistical differences (Student's t-test) between postcontrast SWI and three-dimensional (3D) T1-weighted images regarding the major diameters of the brain tumors. CNR of postcontrast 3D T1-weighted images was statistically superior to that of postcontrast SW images (P < 0.01, Wilcoxon signed-rank test). Malignant tumors tended to have a higher ITSS score. SWI clearly visualized the architecture of brain neoplasms. This imaging technique may be useful for evaluating tumor characterization in clinical use.