Evaluation of tumor response to antiangiogenic therapy in patients with recurrent gliomas using contrast-enhanced perfusion-weighted magnetic resonance imaging techniques:A meta-analysis

BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging(PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications.AIM To determine the diagnostic performance of PW-MRI techniques including:(A)dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI); and(B)dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas.METHODS Databases such as PubMed(MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve(AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval(CI): 0.53-0.82], and the specificity was 0.99(95%CI: 0.93-1) by a random effects model(DerSimonianeeLaird model). The likelihood ratio(LR) +, LR-, and diagnostic odds ratio(DOR)were 12.84(4.54-36.28), 0.35(0.22-0.53), and 24.44(7.19-83.06), respectively. The AUC(± SE) was 0.9921(± 0.0120), and the Q* index(± SE) was 0.9640(± 0.0323).For DSC-MRI, the sensitivity was 0.73, the specificity was 0.98, the LR+ was 7.82,the LR-was 0.32, the DOR was 31.65, the AUC(± SE) was 0.9925(± 0.0132), and the Q* index was 0.9649(± 0.0363). For DCE-MRI, the sensitivity was 0.41, the specificity was 0.97, the LR+ was 5.34, the LR-was 0.71, the DOR was 8.76, the AUC(± SE) was 0.9922(± 0.2218), and the Q* index was 0.8935(± 0.3037).CONCLUSION This meta-analysis demonstrated a beneficial value of PW-MRI(DSC-MRI and DCE-MRI) in monitoring the response of recurrent gliomas to antiangiogenic therapy, with reasonable sensitivity, specificity, +LR, and-LR.

Correlation of MR Perfusion-weighted Imaging of Prostatic Cancer with Tumor Angiogenesis

Objective： MR perfusion-weighted imaging（PWI） has been widely applied in the research of cerebral tumor, benign and malignant musculoskeletal neoplasms and so on. The aim of this study is to explore the application of MR perfusion-weighted imaging in prostatic cancer （Pca）, and evaluate the correlation of PWI features with vascular endothelial growth factor （VEGF） and microvessel density （MVD）. Methods： Twenty-eight consecutive patients who were diagnosed clinically as prostatic cancer and thirty healthy volunteers were examined by PWI. MVD and VEGF were stained with immunohistochemical methods. Some parameters of PWI, including the steepest slope of signal intensity-time curve （SSmax） and the change in relaxation rate （ΔR2^＊peak） at lesions, were analyzed. Correlation analysis was used to determine the relationship between the results of PWI and that of immunohistochemistry. Results： （1） In the healthy volunteers, the steepest slope of signal intensity-time curve （SSmax） and ΔR2^＊peak of perfusion curve were： 0.430±0.011, 2.01±0.7 respectively; however, in the prostatic cancer, they were 57.8±5.0, 3.0±0.6 respectively; with significant difference （t=-4.11, 3.28, P〈0.01）. （2）The VEGF and MVD expression of twenty-eight Pca patients were significantly higher. Conclusion： On MR perfusion- weighted imaging, SSmax and ΔR2^＊peak can reflect MVD and VEGF expression levels in prostatic cancer, suggesting information on tumor angiogenesis. Thus they are beneficial to the diagnosis and treatment of prostatic cancer.

Distinctive magnetic resonance imaging features in primary central nervous system lymphoma:A case report

BACKGROUND Primary central nervous system lymphoma(PCNSL)is a rare malignant tumor originating from the lymphatic hematopoietic system.It exhibits unique imaging manifestations due to its biological characteristics.CASE SUMMARY Magnetic resonance imaging(MRI)with diffusion-weighted imaging(DWI),perfusion-weighted imaging(PWI),and magnetic resonance spectroscopy was performed.The imaging findings showed multiple space-occupying lesions with low signal on T1-weighted imaging,uniform high signal on T2-weighted imaging,and obvious enhancement on contrast-enhanced scans.DWI revealed diffusion restriction,PWI demonstrated hypoperfusion,and spectroscopy showed elevated choline peak and decreased N-acetylaspartic acid.The patient's condition significantly improved after hormone shock therapy.CONCLUSION This case highlights the distinctive imaging features of PCNSL and their importance in accurate diagnosis and management.

Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging

Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging （PWI） and diffusion-weighted imaging （DWI） have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO （5,000 U/kg） 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling （TUNEL） were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.

Advanced imaging techniques in the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the major causes of morbidity and mortality in patients with chronic liver disease. Transarterial chemoembolization(TACE) can significantly improve the survival rate of patients with HCC and is the first treatment choice for patients who are not suitable for surgical resections. The evaluation of the response to TACE treatment affects not only the assessment of the therapy efficacy but also the development of the next step in the treatment plan. The use of imaging to examine changes in tumor volume to assess the response of solid tumors to treatment has been controversial. In recent years, the emergence of new imaging technology has made it possible to observe the response of tumors to treatment prior to any morphological changes. In this article, the advances in studies reporting the use of computed tomography perfusion imaging, diffusionweighted magnetic resonance imaging(MRI), intravoxel incoherent motion, diffusion kurtosis imaging, magnetic resonance spectroscopy, magnetic resonance perfusionweighted imaging, blood oxygen level-dependent MRI, positron emission tomography(PET)/computed tomography and PET/MRI to assess the TACE treatment response are reviewed.

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors(SGTs)make up a small portion(approximately 5%)of all head and neck tumors.Most of them are located in the parotid glands,while they are less frequently located in the submandibular glands,minor salivary glands or sublingual gland.The incidence of malignant or benign tumors(BTs)in the salivary glands varies according to the salivary gland from which they originate.While most of those detected in the parotid gland tend to be benign,the incidence of malignancy increases in other glands.The use of magnetic resonance imaging(MRI)in the diagnosis of SGTs is increasing every day.While conventional sequences provide sufficient data on the presence,localization,extent and number of the tumor,they are insufficient for tumor specification.With the widespread use of advanced techniques such as diffusion-weighted imaging,semiquantitative and quantitative perfusion MRI,studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes.With diffusion MRI,differentiation can be made by utilizing the cellularity and microstructural properties of tumors.For example,SGTs such as high cellular Warthin’s tumor(WT)or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors.Contrast agent uptake and wash-out levels of tumors can be detected with semiquantitative perfusion MRI.For example,it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out.On quantitative perfusion MRI studies using perfusion parameters such as Ktrans,Kep,and Ve,it is reported that WTs can show higher Kep and lower Ve values than other tumors.In this study,the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.

Value of magnetic resonance diffusion combined with perfusion imaging techniques for diagnosing potentially malignant breast lesions

BACKGROUND Lesions of breast imaging reporting and data system(BI-RADS)4 at mammography vary from benign to malignant,leading to difficulties for clinicians to distinguish between them.The specificity of magnetic resonance imaging(MRI)in detecting breast is relatively low,leading to many false-positive results and high rates of re-examination or biopsy.Diffusion-weighted imaging(DWI),combined with perfusion-weighted imaging(PWI),might help to distinguish between benign and malignant BI-RADS 4 breast lesions at mammography.AIM To evaluate the value of DWI and PWI in diagnosing BI-RADS 4 breast lesions.METHODS This is a retrospective study which included patients who underwent breast MRI between May 2017 and May 2019 in the hospital.The lesions were divided into benign and malignant groups according to the classification of histopathological results.The diagnostic efficacy of DWI and PWI were analyzed respectively and combinedly.The 95 lesions were divided according to histopathological diagnosis,with 46 benign and 49 malignant.The main statistical methods used included the Student t-test,the Mann-Whitney U-test,the chi-square test or Fisher’s exact test.RESULTS The mean apparent diffusion coefficient(ADC)values in the parenchyma and lesion area of the normal mammary gland were 1.82±0.22×10^(-3)mm^(2)/s and 1.24±0.16×10^(-3)mm^(2)/s,respectively(P=0.021).The mean ADC value of the malignant group was 1.09±0.23×10^(-3)mm^(2)/s,which was lower than that of the benign group(1.42±0.68×10^(-3)mm^(2)/s)(P=0.016).The volume transfer constant(Ktrans)and rate constant(Kep)values were higher in malignant lesions than in benign ones(all P<0.001),but there were no significant statistical differences regarding volume fraction(V_(e))(P=0.866).The sensitivity and specificity of PWI combined with DWI(91.7%and 89.3%,respectively)were higher than that of PWI or DWI alone.The accuracy of PWI combined with DWI in predicting pathological results was significantly higher than that predicted by PWI or DWI alone.CONCLUSION DWI,combined with PWI,might possibly distinguish between benign and malignant BI-RADS 4 breast lesions at mammography.