Discrimination of Metastatic from Non-metastatic Mesorectal Lymph Nodes in Rectal Cancer Using Quantitative Dynamic Contrast-Enhanced Magnetic Resonance Imaging

Preoperative detection of lymph nodes（LNs） metastasis is always highly challenging for radiologists nowadays. The utility of quantitative dynamic contrast-enhanced magnetic resonance imaging（QDCE-MRI） in identifying LNs metastasis is not well understood. In the present study, 59 patients with histologically proven rectal carcinoma underwent preoperative QDCE-MRI. The short axis diameter ratio, long axis diameter ratio, short-to-long axis diameter ratio and QDEC-MRI parameters（Ktrans, Kep, fPV and Ve） values were compared between the non-metastatic（n=44） and metastatic（n=35） LNs groups based on pathological examination. Compared with the non-metastatic group, the metastatic group exhibited significantly higher short axis diameter（7.558±0.668 mm vs. 5.427±0.285 mm）, Ktrans（0.483±0.198 min-1 vs. 0.218±0.116 min^-1） and Ve（0.399±0.118 vs. 0.203±0.096） values（all P〈0.05）. The short-to-long axis diameter ratio, long axis diameter ratio, Kep and fPV values did not show significant differences between the two groups. In conclusion, our results showed that for LNs larger than 5 mm in rectal cancer, there are distinctive differences in the Ktrans and Ve values between the metastatic and non-metastatic LNs, suggesting that QDCE-MRI may be potentially helpful in identifying LNs status.

Dual-input two-compartment pharmacokinetic model of dynamic contrast-enhanced magnetic resonance imaging in hepatocellular carcinoma

AIM: To investigate the feasibility of a dual-input two-compartment tracer kinetic model for evaluating tumorous microvascular properties in advanced hepatocellular carcinoma(HCC). METHODS: From January 2014 to April 2015, we prospectively measured and analyzed pharmacokinetic parameters [transfer constant(K_(trans)), plasma flow(F_p), permeability surface area product(PS), efflux rate constant(k_(ep)), extravascular extracellular space volume ratio(V_e), blood plasma volume ratio(V_p), and hepatic perfusion index(HPI)] using dual-input two-compartment tracer kinetic models [a dual-input extended Tofts model and a dual-input 2-compartment exchange model(2CXM)] in 28 consecutive HCC patients. A well-known consensus that HCC is a hypervascular tumor supplied by the hepatic artery and the portal vein was used as a reference standard. A paired Student's t-test and a nonparametric paired Wilcoxon rank sum test were used to compare the equivalent pharmacokinetic parameters derived from the two models, and Pearson correlation analysis was also applied to observe the correlations among all equivalent parameters. The tumor size and pharmacokinetic parameters were tested by Pearson correlation analysis, while correlations among stage, tumor size and all pharmacokinetic parameters were assessed by Spearman correlation analysis. RESULTS: The F_p value was greater than the PS value(F_P = 1.07 m L/m L per minute, PS = 0.19 m L/m L per minute) in the dual-input 2CXM; HPI was 0.66 and 0.63 in the dual-input extended Tofts model and the dualinput 2CXM, respectively. There were no significant differences in the K_(ep), V_p, or HPI between the dual-input extended Tofts model and the dual-input 2CXM(P = 0.524, 0.569, and 0.622, respectively). All equivalent pharmacokinetic parameters, except for V_e, were correlated in the two dual-input two-compartment pharmacokinetic models; both Fp and PS in the dualinput 2CXM were correlated with K_(trans) derived from the dual-input extended Tofts model(P = 0.002, r = 0.566; P = 0.002, r = 0.570); K_(ep), V_p, and HPI between the two kinetic models were positively correlated(P = 0.001, r = 0.594; P = 0.0001, r = 0.686; P = 0.04, r = 0.391, respectively). In the dual input extended Tofts model, V_e was significantly less than that in the dual input 2CXM(P = 0.004), and no significant correlation was seen between the two tracer kinetic models(P = 0.156, r = 0.276). Neither tumor size nor tumor stage was significantly correlated with any of the pharmacokinetic parameters obtained from the two models(P > 0.05).CONCLUSION: A dual-input two-compartment pharmacokinetic model(a dual-input extended Tofts model and a dual-input 2CXM) can be used in assessing the microvascular physiopathological properties before the treatment of advanced HCC. The dual-input extended Tofts model may be more stable in measuring the V_e; however, the dual-input 2CXM may be more detailed and accurate in measuring microvascular permeability.

Texture analysis on parametric maps derived from dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer

AIM: To investigate the merits of texture analysis on parametric maps derived from pharmacokinetic modeling with dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) as imaging biomarkers for the prediction of treatment response in patients with head and neck squamous cell carcinoma(HNSCC). METHODS: In this retrospective study,19 HNSCC patients underwent pre- and intra-treatment DCEMRI scans at a 1.5T MRI scanner. All patients had chemo-radiation treatment. Pharmacokinetic modeling was performed on the acquired DCE-MRI images,generating maps of volume transfer rate(Ktrans) and volume fraction of the extravascular extracellular space(ve). Image texture analysis was then employed on maps of Ktrans and ve,generating two texture measures: Energy(E) and homogeneity.RESULTS: No significant changes were found for the mean and standard deviation for Ktrans and ve between pre- and intra-treatment(P > 0.09). Texture analysis revealed that the imaging biomarker E of ve was significantly higher in intra-treatment scans,relative to pretreatment scans(P < 0.04). CONCLUSION: Chemo-radiation treatment in HNSCC significantly reduces the heterogeneity of tumors.

Dynamic contrast-enhanced magnetic resonance imaging of prostate cancer: A review of current methods and applications

In many areas of oncology, dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) has proven to be a clinically useful, non-invasive functional imaging technique to quantify tumor vasculature and tumor perfusion characteristics. Tumor angiogenesis is an essential process for tumor growth, proliferation, and metastasis. Malignant lesions demonstrate rapid extravasation of contrast from the intravascular space to the capillary bed due to leaky capillaries associated with tumor neovascularity. DCE-MRI has the potential to provide information regarding blood flow, areas of hypoperfusion, and variations in endothelial permeability and microvessel density to aid treatment selection, enable frequent monitoring during treatment and assess response to targeted therapy following treatment. This review will discuss the current status of DCE-MRI in cancer imaging, with a focus on its use in imaging prostate malignancies as well as weaknesses that limit its widespread clinical use. The latest techniques for quantification of DCE-MRI parameters will be reviewed and compared.

Prediction of radiosensitivity in primary central nervous system germ cell tumors using dynamic contrast-enhanced magnetic resonance imaging

Objective： To evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging（DCEMRI） for predicting tumor response to radiotherapy in patients with suspected primary central nervous system（CNS） germ cell tumors（GCTs）.Methods： DCE-MRI parameters of 35 patients with suspected primary CNS GCTs were obtained prior to diagnostic radiation, using the Tofts and Kermode model. Radiosensitivity was determined in tumors diagnosed 2 weeks after radiation by observing changes in tumor size and markers as a response to MRI. Taking radiosensitivity as the gold standard, the cut-off value of DCE-MRI parameters was measured by receiver operating characteristic（ROC） curve. Diagnostic accuracy of DCE-MRI parameters for predicting radiosensitivity was evaluated by ROC curve.Results： A significant elevation in transfer constant（K^trans） and extravascular extracellular space（Ve）（P=0.000）, as well as a significant reduction in rate constant（Kep）（P=0.000） was observed in tumors. K^trans, relative K^trans, and relative Kep of the responsive group were significantly higher than non-responsive groups. No significant difference was found in Kep, Ve, and relative Ve between the two groups. Relative K^trans showed the best diagnostic value in predicting radiosensitivity with a sensitivity of 100%, specificity of 91.7%, positive predictive value（PPV） of 95.8%, and negative predictive value（NPV） of 100%.Conclusions： Relative K^trans appeared promising in predicting tumor response to radiation therapy（RT）. It is implied that DCE-MRI pre-treatment is a requisite step in diagnostic procedures and a novel and reliable approach to guide clinical choice of RT.

Magnetic resonance imaging of the cirrhotic liver: An update

Noninvasive imaging has become the standard for hepatocellular carcinoma(HCC) diagnosis in cirrhotic livers. In this review paper, we go over the basics of MR imaging in cirrhotic livers and describe the imaging appearance of a spectrum of hepatic nodules marking the progression from regenerative nodules to low- and high-grade dysplastic nodules, and ultimately to HCCs. We detail and illustrate the typical imaging appearancesof different types of HCC including focal, multifocal, massive, diffuse/infiltrative, and intra-hepatic metastases; with emphasis on the diagnostic value of MR in imaging these lesions. We also shed some light on liver imaging reporting and data system, and the role of different magnetic resonance imaging(MRI) contrast agents and future MRI techniques including the use of advanced MR pulse sequences and utilization of hepatocyte-specific MRI contrast agents, and how they might contribute to improving the diagnostic performance of MRI in early stage HCC diagnosis.

Intraoperative perfusion magnetic resonance imaging: Cutting-edge improvement in neurosurgical procedures

The goal in brain tumor surgery is to remove the maxi-mum achievable amount of the tumor, preventing damage to "eloquent" brain regions as the amount of brain tumor resection is one of the prognostic factors for time to tumor progression and median survival. To achieve this goal, a variety of technical advances have been in-troduced, including an operating microscope in the late 1950 s, computer-assisted devices for surgical navigation and more recently, intraoperative imaging to incorporate and correct for brain shift during the resection of the lesion. However, surgically induced contrast enhancement along the rim of the resection cavity hampers interpretation of these intraoperatively acquired magnetic resonance images. To overcome this uncertainty, perfusion techniques [dynamic contrast enhanced magnetic resonance imaging(DCE-MRI), dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI)] have been introduced that can differentiate residual tumor from surgically induced changes at the rim of the resec-tion cavity and thus overcome this remaining uncer-tainty of intraoperative MRI in high grade brain tumor resection.

Clinical applications of advanced magnetic resonance imaging techniques for arthritis evaluation

Magnetic resonance imaging(MRI) has allowed a comprehensive evaluation of articular disease, increasing the detection of early cartilage involvement, bone erosions, and edema in soft tissue and bone marrow compared to other imaging techniques. In the era of functional imaging, new advanced MRI sequences are being successfully applied for articular evaluation in cases of inflammatory, infectious, and degenerative arthropathies. Diffusion weighted imaging, new fat suppression techniques such as DIXON, dynamic contrast enhanced-MRI, and specific T2 mapping cartilage sequences allow a better understanding of the physiopathological processes that underlie these different arthropathies. They provide valuable quantitative information that aids in their differentiation and can be used as potential biomarkers of articular disease course and treatment response.

Perfusion magnetic resonance imaging of the liver

Perfusion magnetic resonance imaging (MRI) studies quantify the microcirculatory status of liver parenchyma and liver lesions, and can be used for the detection of liver metastases, assessing the effectiveness of antiangiogenic therapy, evaluating tumor viability after anticancer therapy or ablation, and diagnosis of liver cirrhosis and its severity. In this review, we discuss the basic concepts of perfusion MRI using tracer kinetic modeling, the common kinetic models applied for analyses, the MR scanning techniques, methods of data processing, and evidence that supports its use from published clinical and research studies. Technical standardization and further studies will help to establish and validate perfusion MRI as a clinical imaging modality.

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.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension:A review

Among five types of pulmonary hypertension,chronic thromboembolic pulmonary hypertension(CTEPH)is the only curable form,but prompt and accurate diagnosis can be challenging.Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH,however these are limited by radiation exposure,subjective qualitative bias,and lack of cardiac functional assessment.This review aims to assess the methodology,diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages,limitations and future research scope.

Differentiation between dysplastic nodule and early-stage hepatocellular carcinoma: The utility of conventional MR imaging

AIM:To elucidate the variety of ways early-stage hepatocellular carcinoma(HCC)can appear on magnetic resonance(MR)imaging by analyzing T1-weighted,T2-weighted,and gadolinium-enhanced dynamic studies.METHODS:Seventy-three patients with well-differentiated HCC(wHCC)or dysplastic nodules were retrospectively identified from medical records,and new histological sections were prepared and reviewed.The tumor nodules were categorized into three groups:dysplastic nodule(DN),wHCC compatible with Edmondson-Steiner grade I HCC(w1-HCC),and wHCC compatible with Edmondson-Steiner gradeⅡHCC(w2-HCC).The signal intensity on pre-contrast MR imaging and the enhancing pattern for each tumor were recorded and compared between the three tumor groups.RESULTS:Among the 73 patients,14 were diagnosed as having DN,40 were diagnosed as having w1-HCC,and 19 were diagnosed as having w2-HCC.Hyperintensity measurements on T2-weighted axial images(T2WI)were statistically significant between DNs and wHCC(P=0.006)and between DN and w1-HCC(P=0.02).The other imaging features revealed no significant differences between DN and wHCC or between DN and w1-HCC.Hyperintensity on both T1W out-phase imaging(P=0.007)and arterial enhancement on dynamic study(P=0.005)showed statistically significant differences between w1-HCC and w2-HCC.The other imaging features revealed no significant differences between w1-HCC and w2-HCC.CONCLUSION:In the follow-up for a cirrhotic nodule,increased signal intensity on T2WI may be a sign of malignant transformation.Furthermore,a noted loss of hyperintensity on T1WI and the detection of arterial enhancement might indicate further progression of the histological grade.

Dynamic contrast-enhanced MRI versus ^(18)F-FDG PET/CT: Which is better in differentiation between malignant and benign solitary pulmonary nodules?

Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed tomography（PET/CT） in the differentiation of malignant and benign solitary pulmonary nodules（SPNs）.Methods： Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs. All these patients underwent DCE-MRI and ^18F-FDG PET/CT examinations. The quantitative MRI pharmacokinetic parameters, including the trans-endothelial transfer constant（K^trans）, redistribution rate constant（Kep）, and fractional volume（Ve）, were calculated using the Extended-Tofts Linear two-compartment model. The ^18F-FDG PET/CT parameter, maximum standardized uptake value（SUV（max））, was also measured. Spearman＇s correlations were calculated between the MRI pharmacokinetic parameters and the SUV（max） of each SPN. These parameters were statistically compared between the malignant and benign nodules. Receiver operating characteristic（ROC） analyses were used to compare the diagnostic capability between the DCE-MRI and ^18F-FDG PET/CT indexes.Results： Positive correlations were found between K^trans and SUV（max）, and between K（ep） and SUV（max）（P〈0.05）.There were significant differences between the malignant and benign nodules in terms of the K^trans, K（ep） and SUV（max） values（P〈0.05）. The areas under the ROC curve（AUC） of K^trans） K（ep） and SUV（max） between the malignant and benign nodules were 0.909, 0.838 and 0.759, respectively. The sensitivity and specificity in differentiating malignant from benign SPNs were 90.6% and 82.4% for K^trans; 87.5% and 76.5% for K（ep）; and 75.0% and 70.6%for SUV（max）, respectively. The sensitivity and specificity of K^trans and K（ep） were higher than those of SUV（max）, but there was no significant difference between them（P〉0.05）.Conclusions： DCE-MRI can be used to differentiate between benign and malignant SPNs and has the advantage of being radiation free.

Enhancement patterns of small hepatocellular carcinoma shown by dynamic MRI and CT

Objectives: To study prospectively the enhancement features of small hepatocellular carcinoma (SHCC) with multi-phase scanning of dynamic MRI and spi- ral CT, and discuss the superiority of dynamic MRI to spiral CT. Methods: Multi-phase dynamic contrast scanning of high field MRI and spiral CT were performed in 53 patients with SHCC. The arterial phase, portal ve- nous phase and delayed phase scanning of spiral CT was done after the pre-contrast scanning of the entire liver. MRI was performed with SE sequence and fast multiplanar spoiled gradient-recalled sequence dy- namic multi-phase contrast scanning. Results: Seventy-six lesions were found in all 53 pa- tients. Sixty-nine and 54 of the 76 lesions enhanced obviously in MRI and spiral CT arterial phase scan- ning respectively. The typical enhancement patterns of SHCC in the arterial phase, portal venous phase and delayed phase scanning of MRI and spiral CT were hyper-hypo-hypointense (dense) and hyper-iso- hypointense (dense). Atypical enhancement patterns were hyper-hyper-hyperintense (dense), hyper-iso- isointense (dense) and hypo-hypo-hypointense (dense). Conclusions: Both MRI and spiral CT multi-phase dynamic contrast-enhanced scanning could demon- strate the enhancement features of SHCC, and arte- rial phase scan of MRI was superior to spiral CT in reflecting the hypervascular characterization of SHCC. In addition, MRI was better than spiral CT in characterization of hepatic lesions combined with SE sequence.

Diagnosis value of diffusion-weighted MR imaging with dynamic enhanced scanning toward pancreatic endocrine tumors

Objective： The aim of our study was to analysis the pictures of conventional magnetic resonance imaging （MR）, diffusion-weighted imaging （DWl） and dynamic enhanced magnetic resonance imaging （DEMRI） of pancreatic endocrine tumors （PETs）, and evaluate diagnostic value of MR, DWl and DEMRI for diagnosing PETs. Methods： DWl and DEMRI scanning toward 13 patients with PETs being confirmed by surgical pathology before surgery on the basis of conventional MR scanning were carried out, and MR findings was analyzed retrospectively. Results： Of 13 patients with PETs there was 11 cases with single lesion, 2 with multiple, and had 15 lesions altogether, of which there were 3 lesions in pancreatic head, 1 in its neck, 2 in its body, 4 in its body and tail, 5 in its tail. MR findings： （1） T1WI signal was low or slightly lower （9/15）, and equal ones （5/15）; （2） T2WI showed high or slightly higher signal （10/15）, and equal ones （5/15）; （3） T1WI with fat suppression： the signal was low （11/15）, mixed signal （2/15）, and equal ones （2/15）; （4） DWI： normal pancreatic tissue exhibited homogeneous intermediate signal, all 15 lesions were high or slightly higher signal, the measured ADC values of tissue of PETs was （1.124 ± 0.252） × 104 mm2/s, and the ADC value of normal pancreatic tissue （1.873 ± 0.157） × 10^3 mm2/s; （5） Enhanced （M3D/LAVA） scanning： among 13 patients with PETs there were 12 pancreatic lesions with significantly enhanced signals in the arterial phase in all 15, and significantly higher than normal pancreatic tissue, and two slight enhancement was slightly higher signal; and 1 no enhancement. Enhanced pattern： homogeneous enhancement were 6 lesions, and the heterogeneous 4, and the edge ring 5. Conclusion： MR and DWl combining with DEMRI help qualitative diagnosis of pancreatic endocrine tumors.

BLOOD FLOW PATTERN AND QUANTITATIVE STUDY IN SOLITARY PULMONARY NODULES WITH DYNAMIC CONTRAST-ENHANCED MRI

Objective To evaluate the efficacy of contrast enhanced dynamic MRI in differentiating solitary pulmonary nodules（SPNs）. Methods Eighty-three patients with SPNs undertaken contrast enhanced dynamic MRI. Time-signal intensity curve （T-SI Curve） was made. Peak height （PH） , steepest slope （SS）, maximum enhancement （ Emax ） and the enhancement rates of signal intensity were recorded at the frst （ E1 ）, second （ E2 ）, third （ E3 ） , fourth （ E4 ） , fifth （E5）, and sixth （ E6 ） minute after injection. Results Malignant nodules and inflammatory nodules enhanced significantly higher than benign nodules, and malignant nodules and inflammatory nodules showed obviously higher PH, SS, Emax, El-E6 values than benign nodules （ P 〈 0. 01 ）. There were no sig- nificant differences in PH, SS, Emax, E1-E6 values between malignant nodules and inflammatory nodules （P 〉 0. 05）. Conclusion Contrast enhanced dynamic MR imaging can provide SPNs＇ hemodynamic information and is helpful in differentiating SPNs.

Diagnostic value of DWI combined with dynamic contrast-enhanced scan of cervical cancer staging弥散加权成像结合动态增强扫描在宫颈癌分期中的诊断价值

目的探讨磁共振弥散加权成像（DWI）结合动态增强扫描在子宫颈癌分期中的诊断价值。方法回顾性分析2013年11月-2014年8月广州医科大学附属第四医院56例经病理证实的宫颈癌患者的DWI及动态增强扫描结果。测量病灶表观扩散系数（ADC）值判断浸润范围，并与手术病理结果进行比较。结果宫颈癌在DWI图像上表现为高信号，ADC值降低，平均ADC值为（0．92±0．16）×10^-3mm^2／s。动态增强扫描早期病灶明显快速强化，延迟期病灶中心呈低信号，病灶边缘呈稍高信号，与邻近正常宫颈组织信号明显不同，形成对比。DWI结合动态增强扫描对宫颈癌FIGO分期（2009）总准确性为93．75％，高于常规MRI分期总准确性（81．25％），对宫旁浸润评估的准确性为100．00％。结论，DWI结合动态增强扫描磁共振检查能提高宫颈癌侵犯程度评价的准确性，对宫颈癌的诊断、临床分期及制订正确的治疗方案具有重要意义。

Classification of breast lesions based on a dual S-shaped logistic model in dynamic contrast enhanced magnetic resonance imaging

This study proposes a novel dual S-shaped logistic model for automatically quantifying the characteristic kinetic curves of breast lesions and for distinguishing malignant from benign breast tumors on dynamic contrast enhanced (DCE) magnetic resonance (MR) images.D(,) is the diagnostic parameter derived from the logistic model.Significant differences were found in D(,) between the malignant benign groups.Fisher's Linear Discriminant analysis correctly classified more than 90% of the benign and malignant kinetic breast data using the derived diagnostic parameter (D(,)).Receiver operating characteristic curve analysis of the derived diagnostic parameter (D(,)) indicated high sensitivity and specificity to differentiate malignancy from benignancy.The dual S-shaped logistic model was effectively used to fit the kinetic curves of breast lesions in DCE-MR.Separation between benign and malignant breast lesions was achieved with sufficient accuracy by using the derived diagnostic parameter D(,) as the lesion's feature.The proposed method therefore has the potential for computer-aided diagnosis in breast tumors.

Value of magnetic resonance imaging including dynamic contrast-enhanced magnetic resonance imaging in differentiation between inverted papilloma and malignant tumors in the nasal cavity

Background Distinguishing inverted papilloma （IP） from malignant tumors in the nasal cavity is difficult in a substantial number of cases,thus hindering the administration of appropriate therapeutic strategies.This study aimed to evaluate whether magnetic resonance imaging （MRI）,including dynamic contrast enhanced MRI （DCE-MRI）,could improve differentiation between IP and malignant tumors,and to identify which MRI features were the best in discriminating IP from malignant tumors in the nasal cavity.Methods Non-enhanced,static,and dynamic contrast enhanced MRI was performed in 88 patients with an IP or a malignant tumor in the nasal cavity that had been confirmed by histological results.MRI features of IP and malignant tumors including side,margin,T1 signal intensity,T1 homogeneity,T2 signal intensity,T2 homogeneity,lobulation signs,convoluted cerebriform pattern,extra-sinonasal involvement,pattern of enhancement,Tpeak,Tmax,Clmax,and TIC type were evaluated and correlated with histological findings.Results There were significant differences between IP and malignant tumors in T2 homogeneity,Iobulation signs,convoluted cerebriform pattern,extra-sinonasal involvement,Tpeak,Tmax and TIC types.A convoluted cerebriform pattern had a higher sensitivity and specificity in diagnosis of IP while washout-type TIC had a higher sensitivity and specificity in diagnosis of malignant tumors in the nasal cavity.Non-enhanced combined with static and dynamic enhancement MRI was significantly superior to non-enhanced combined with static enhancement MRI in the differentiation of IP and malignant tumors in the nasal cavity.Multivariate logistic regression analysis identified that the best MRI features were a convoluted cerebriform pattern,extra-sinonasal involvement,and washout-type TIC for both observers （Wang XY and Zhang ZY）.Conclusion Non-enhanced and static combined with dynamic contrast-enhanced MRI improves differentiation of IP and malignant tumors in the nasal cavity.

Improved Performance in Differentiating Benign from Malignant Sinonasal Tumors Using Diffusion-weighted Combined with Dynamic Contrast-enhanced Magnetic Resonance Imaging

Background：Differentiating benign from malignant sinonsal lesions is essential for treatment planning as well as determining the patient＇s prognosis,but the differentiation is often difficult in clinical practice.The study aimed to determine whether the combination of diffusion-weighted （DW） and dynamic contrast-enhanced magnetic resonance imaging （DCE-MRI） can improve the performance in differentiating benign from malignant sinonasal tumors.Methods：This retrospective study included 197 consecutive patients with sinonasal tumors （116 malignant tumors and 81 benign tumors）.All patients underwent both DW and DCE-MRI in a 3-T magnetic resonance scanner.Two different settings ofb values （0,700 and 0,1000 s/mm^2） and two different strategies of region of interest （ROI） including whole slice （WS） and partial slice （PS） were used to calculate apparent diffusion coefficients （ADCs）.A DW parameter with WS ADCsb0.1000 and two DCE-MRI parameters （time intensity curve [TIC] and time to peak enhancement [Tpeak]） were finally combined to use in differentiating the benign from the malignant tumors in this study.Results：The mean ADCs of malignant sinonasal tumors （WS ADCsb0,1000=1.084 × 10^-3 mm^2/s） were significantly lower than those of benign tumors （WS ADCsb0,1000=1.617 × 10^-3 mm^2/s,P 〈 0.001）.The accuracy using WS ADCsb0,1000 alone was 83.7% in differentiating the benign from the malignant tumors （85.3% sensitivity,81.2% specificity,86.4% positive predictive value [PPV],and 79.5% negative predictive value [NPV]）.The accuracy using DCE with Tpeak and TIC alone was 72.1% （69.1% sensitivity,74.1% specificity,77.5% PPV,and 65.1% NPV）.Using DW-MRI parameter was superior than using DCE parameters in differentiation between benign and malignant sinonasal tumors （P 〈 0.001）.The accuracy was 87.3% （90.5% sensitivity,82.7% specificity,88.2% PPV,and 85.9% NPV） using DW-MRI combined with DCE-MRI,which was superior than that using DCE-MRI alone or using DW-MRI alone （both P 〈 0.001） in differentiating the benign from the malignant tumors.Conclusions：Diffusion-weighted combined with DCE-MRI can improve imaging performance in differentiating benign from malignant sinonasal tumors,which has the potential to improve diagnostic accuracy and to provide added value in the management for these tumors.