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.

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.

Application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)combined with magnetic resonance spectroscopy(MRS)in prostate cancer diagnosis

Objective The aim of the study was to investigate the application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)combined with magnetic resonance spectroscopy(MRS)in prostate cancer diagnosis.Methods In the outpatient department of our hospital(Sichuan Cancer Hospital,Chengdu,China),60 patients diagnosed with prostate disease were selected randomly and included in a prostate cancer group,60 patients with benign prostatic hyperplasia were included in a proliferation group,and 60 healthy subjects were included in a control group,from January 2013 to January 2017.Using Siemens Avanto 1.5 T high-field superconducting MRI for DCE-MRI and MRS scans,after the MRS scan was completed,we used the workstation spectroscopy tab spectral analysis,and eventually obtained the crest lines of the prostate metabolites choline(Cho),creatine(Cr),citrate(Cit),and the values of Cho/Cit,and(Cho+Cr)/Cit.Results Participants who had undergone 21-s,1-min,and 2-min dynamic contrast-enhanced MR revealed significant variations among the three groups.The spectral analysis of the three groups revealed a significant variation as well.DCE-MRI and MRS combined had a sensitivity of 89.67%,specificity of 95.78%,and accuracy of 94.34%.Conclusion DCE-MRI combined with MRS is of great value in the diagnosis of prostate cancer.

Evaluating pediatric ureteropelvic junction obstruction:Dynamic magnetic resonance urography vs renal scintigraphy 99mtechnetium mercaptoacetyltriglycine

BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to symptomatic occurrence.AIM To evaluate the discrepancy between dynamic contrast-enhanced magnetic resonance urography(dMRU)and scintigraphy 99m-technetium mercaptoacetyltriglycine(MAG-3)for the functional evaluation of UPJO.METHODS Between 2016 and 2020,126 patients with UPJO underwent surgery at Robert DebréHospital.Of these,83 received a prenatal diagnosis,and 43 were diagnosed during childhood.Four of the 126 patients underwent surgery based on the clinical situation and postnatal ultrasound findings without undergoing functional imaging evaluation.Split renal function was evaluated preoperatively using scintigraphy MAG-3(n=28),dMRU(n=53),or both(n=40).In this study,we included patients who underwent surgery for UPJO and scintigraphy MAG-3+dMRU but excluded those who underwent only scintigraphy MAG-3 or dMRU.The patients were divided into groups A(<10%discrepancy)and B(>10%discrepancy).We examined the discrepancy in split renal function between the two modalities and investigated the possible risk factors.RESULTS The split renal function between the two kidneys was compared in 40 patients(28 boys and 12 girls)using scintigraphy MAG-3 and dMRU.Differential renal function,as determined using both modalities,showed a difference of<10%in 31 children and>10%in 9 children.Calculation of the relative renal function using dMRU revealed an excellent correlation coefficient with renal scintigraphy MAG-3 for both kidneys.CONCLUSION Our findings demonstrated that dMRU is equivalent to scintigraphy MAG-3 for evaluating split renal function in patients with UPJO.

Quantitative parameters of dynamic contrast-enhanced magnetic resonance imaging of hepatic benign and malignant lesions and their clinical value

Objective:To determine the quantitative parameter levels of dynamic contrast-enhanced magnetic resonance imaging (MRI) of hepatic benign and malignant lesions and to explore their value for the evaluation of the disease.Methods: A total of 67 patients with primary liver cancer and 78 patients with hepatic benign lesion were selected as the liver cancer group and hepatic benign lesion group respectively. The preoperative quantitative parameter levels of dynamic contrast-enhanced MRI of the two groups were measured, and the correlation of the specific parameter levels with liver cancer-related proliferation and invasion gene expression was evaluated.Results: The mean time to enhance (MET) and maximum slope of increase (MSI) levels of the liver cancer group were lower than those of the hepatic benign lesion group while the maximum slope of decrease (MSD) level was higher than that of the hepatic benign lesion group. Proliferation genes PRMT5, CDCA5, SIRT2, XIAP and Cep55 mRNA expression in the lesion tissues of the liver cancer group were all higher than those of the hepatic benign lesion group;invasion genes Cripto-1 and IFITM3 mRNA expression were higher than those of the hepatic benign lesion group while KLF4 and HOXA9 mRNA expression were lower than those of the hepatic benign lesion group. Pearson test showed that the quantitative parameters MET, MSI and MSD levels of dynamic contrast-enhanced MRI in liver cancer tissues were directly correlated with the proliferation and invasion activity of cancer cells.Conclusion: The quantitative parameters MET, MSI and MSD levels of dynamic contrast-enhanced MRI of liver cancer are significantly abnormal, and the specific levels could objectively reflect the tumor malignancy.

Optimization of hepatobiliary phase delay time of Gd-EOB-DTPA-enhanced magnetic resonance imaging for identification of hepatocellular carcinoma in patients with cirrhosis of different degrees of severity

AIM To optimize the hepatobiliary phase delay time(HBPDT) of Gd-EOB-DTPA-enhanced magnetic resonance imaging(GED-MRI) for more efficient identification of hepatocellular carcinoma(HCC) occurring in different degrees of cirrhosis assessed by Child-Pugh(CP) score.METHODS The liver parenchyma signal intensity(LPSI), the liver parenchyma(LP)/HCC signal ratios, and the visibility of HCC at HBP-DT of 5, 10, 15, 20, and 25 min(i.e., DT-5, DT-10, DT-15, DT-20, and DT-25) after injection of GdEOB-DTPA were collected and analyzed in 73 patients with cirrhosis of different degrees of severity(including 42 patients suffering from HCC) and 18 healthy adult controls.RESULTS The LPSI increased with HBP-DT more significantly in the healthy group than in the cirrhosis group(F = 17.361, P < 0.001). The LP/HCC signal ratios had a significant difference(F = 12.453, P < 0.001) among various HBP-DT points, as well as between CP-A and CP-B/C subgroups(F = 9.761, P < 0.001). The constituent ratios of HCC foci identified as obvious hypointensity(+++), moderate hypointensity(++), and mild hypointensity or isointensity(+/-) kept stable from DT-10 to DT-25: 90.6%, 9.4%, and 0.0% in the CP-A subgroup; 50.0%, 50.0%, and 0.0% in the CP-B subgroup; and 0.0%, 0.0%, and 100.0% in the CP-C subgroup, respectively.CONCLUSION The severity of liver cirrhosis has significant negative influence on the HCC visualization by GED-MRI. DT-10 is more efficient and practical than other HBP-DT points to identify most of HCC foci emerging in CP-A cirrhosis, as well as in CP-B cirrhosis; but an HBP-DT of 15 min or longer seems more appropriate than DT-10 for visualization of HCC in patients with CP-C cirrhosis.

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.

Magnetic resonance imaging of the liver:New imaging strategies for evaluating focal liver lesions

The early detection of focal liver lesions,particularly those which are malignant,is of utmost importance.The resection of liver metastases of some malignancies(including colorectal cancer)has been shown to improve the survival of patients.Exact knowledge of the number,size,and regional distribution of liver metastases is essential to determine their resectability.Almost all focal liver lesions larger than 10 mm are demonstrated with current imaging techniques but the detection of smaller focal liver lesions is still relatively poor.One of the advantages of magnetic resonance imaging(MRI)of the liver is better soft tissue contrast(compared to other radiologic modalities),which allows better detection and characterization of the focal liver lesions in question.Developments in MRI hardware and software and the availability of novel MRI contrast agents have further improved the diagnostic yield of MRI in lesion detection and characterization.Although the primary modalities for liver imaging are ultrasound and computed tomography,recent studies have suggested that MRI is the most sensitive method for detecting small liver metastatic lesions,and MRI is now considered the pre-operative standard method for diagnosis.Two recent developments in MRI sequences for the upper abdomen comprise unenhanced diffusion-weighted imaging(DWI),and keyhole-based dynamic contrast-enhanced(DCE)MRI(4D THRIVE).DWI allows improved detection(b=10 s/mm2)of small(<10 mm)focal liver lesions in particular,and is useful as a road map sequence.Also,using higher b-values,the calculation of the apparent diffusion coefficient value,true diffusion coefficient,D,and the perfusion fraction,f,has been used for the characterization of focal liver lesions.DCE 4D THRIVE enables MRI of the liver with high temporal and spatial resolution and full liver coverage.4D THRIVE improves evaluation of focal liver lesions,providing multiple arterial and venous phases,and allows the calculation of perfusion parameters using pharmacokinetic models.4D THRIVE has potential benefits in terms of detection,characterization and staging of focal liver lesions and in monitoring therapy.

Diagnostic performance of contrast-enhanced ultrasound and enhanced magnetic resonance for breast nodules

In the current study, we sought to evaluate the diagnostic efficacies of conventional ultrasound（US）, contrastenhanced US（CEUS）, combined US and CEUS and magnetic resonance imaging（MRI） in detecting focal solid breast lesions. Totally 117 patients with 120 BI-RADS category 4A-5 breast lesions were evaluated by conventional US and CEUS, and MRI, respectively. SonoVue was used as contrast agent in CEUS and injected as an intravenous bolus; nodule scan was performed 4 minutes after bolus injection. A specific sonographic quantification software was used to obtain color-coded maps of perfusion parameters for the investigated lesion, namely the time-intensity curve.The pattern of contrast enhancement and related indexes regarding the time-intensity curve were used to describe the lesions, comparatively with pathological results. Histopathologic examination revealed 46 benign and 74 malignant lesions. Sensitivity, specificity, and accuracy of US in detecting malignant breast lesions were 90.14%, 95.92%, and 92.52%, respectively. Meanwhile, CE-MRI showed sensitivity, specificity, and accuracy of 88.73%, 95.92%, and91.67%, respectively. The area under the ROC curve for combined US and CEUS in discriminating benign from malignant breast lesions was 0.936, while that of MRI was 0.923, with no significant difference between them, as well as among groups. The time-intensity curve of malignant hypervascular fibroadenoma and papillary lesions mostly showed a fast-in/fast-out pattern, with no good correlation between them（kappa 〈0.20）. In conclusion, the combined use of conventional US and CEUS displays good agreement with MRI in differentiating benign from malignant breast lesions.

Reversible lesions in the brain parenchyma in Wilson's disease confirmed by magnetic resonance imaging:earlier administration of chelating therapy can reduce the damage to the brain

The aim of this study was to evaluate the resolution of brain lesions in patients with Wilson’s disease during the long-term chelating therapy using magnetic resonance imaging and a possible signiifcance of the time latency between the initial symptoms of the disease and the introduction of this therapy. Initial magnetic resonance examination was performed in 37 patients with proven neurological form of Wilson’s disease with cerebellar, parkinsonian and dystonic presentation. Magnetic resonance reexamination was done 5.7 ± 1.3 years later in 14 patients. Patients were divided into： group A, where chelating therapy was initiated 〈 24 months from the ifrst symp-toms and group B, where the therapy started≥ 24 months after the initial symptoms. Symmetry of the lesions was seen in 100% of patients. There was a signiifcant difference between groups A and B regarding complete resolution of brain stem and putaminal lesions （P= 0.005 andP=0.024, respectively）. If the correct diagnosis and adequate treatment are not established less than 24 months after onset of the symptoms, irreversible lesions in the brain parenchyma could be ex-pected. Signal abnormalities on magnetic resonance imaging might therefore, at least in the early stages, represent reversible myelinolisis or cytotoxic edema associated with copper toxicity.

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.

Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability

Spinal cord injury（SCI） affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound（MRg FUS） as a non-invasive approach to increase permeability in the blood-spinal cord barrier（BSCB）. We hypothesize that localized, controlled sonoporation of the BSCB by MRg FUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRg FUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRg FUS blood spinal cord barrier opening. Then, in normal rats, MRg FUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

Diagnostic performance of abbreviated gadoxetic acid-enhanced magnetic resonance protocols with contrast-enhanced computed tomography for detection of colorectal liver metastases

BACKGROUND Although contrast-enhanced magnetic resonance imaging(MRI)using gadoxetic acid has been shown to have higher accuracy,sensitivity,and specificity for the detection and characterization of hepatic metastases compared with other modalities,the long examination time would limit the broad indication.Several abbreviated enhanced MRI(Ab-MRI)protocols without dynamic phases have been proposed to achieve equivalent diagnostic performance for the detection of colorectal liver metastases.However,an optimal protocol has not been established,and no studies have assessed the diagnostic performance of Ab-MRI combined with contrast-enhanced computed tomography(CE-CT),which is the preoperative imaging of colorectal cancer staging in clinical settings,to determine the best therapeutic strategy.AIM To compare the diagnostic performance of two kinds of Ab-MRI protocol with the standard MRI protocol and a combination of the Ab-MRI protocol and CE-CT for the detection of colorectal liver metastases.METHODS Study participants comprised 87 patients(51 males,36 females;mean age,67.2±10.8 years)who had undergone gadoxetic acid-enhanced MRI and CE-CT during the initial work-up for colorectal cancer from 2010 to 2021.Each exam was independently reviewed by two readers in three reading sessions:(1)Only single-shot fast spin echo(FSE)T2-weighted or fat-suppressed-FSE-T2-weighted,diffusion-weighted,and hepatobiliary-phase images(Ab-MRI protocol 1 or 2);(2)all acquired MRI sequences(standard protocol);and(3)a combination of an Ab-MRI protocol(1 or 2)and CE-CT.Diagnostic performance was then statistically analyzed.RESULTS A total of 380 Lesions were analyzed,including 195 metastases(51.4%).Results from the two Ab-MRI protocols were similar.The sensitivity,specificity,and positive and negative predictive values from Ab-MRI were non-inferior to those from standard MRI(P>0.05),while those from the combination of Ab-MRI protocol and CE-CT tended to be higher than those from Ab-MRI alone,although the difference was not significant(P>0.05),and were quite similar to those from standard MRI(P>0.05).CONCLUSION The diagnostic performances of two Ab-MRI protocols were non-inferior to that of the standard protocol.Combining Ab-MRI with CE-CT provided better diagnostic performance than Ab-MRI alone.

Spectrum of intracranial incidental findings on pediatric brain magnetic resonance imaging:What clinician should know?

Intracranial incidental findings on magnetic resonance imaging(MRI) of the brain continue to generate interest in healthy control,research,and clinical subjects.However,in clinical practice,the discovery of incidental findings acts as a "distractor".This review is based on existing heterogeneous reports,their clinical implications,and how the results of incidental findings influence clinical management.This draws attention to the followings:(1) the prevalence of clinically significant incidental findings is low;(2) there is a lack of a systematic approach to classification;and discusses(3) how to deal with the detected incidental findings based a proposed common clinical profile.Individualized neurological care requires an active discussion regarding the need for neuroimaging.Clinical significance of incidental findings should be decided based on lesion's neuroradiologic characteristics in the given clinical context.Available evidence suggests that the outcome of an incidentally found "serious lesion in children" is excellent.Future studies of intracranial incidental findings on pediatric brain MRI should be focused on a homogeneous population.The study should address this clinical knowledge based review powered by the statistical analyses.

Preliminary clinical application using 3D time-resolved imaging of contrast-enhanced MR angiography of contrast kinetics （3D-TRICKS）i

Objective：To introduce a new better contrast-enhanced MR angiographic metnod, named 3D time-resolved imaging of contrast kinetics （3D-TRICKS）. Methods： TRICKS is a high temporal resolution （2-6 s） MR angiographic technique using a short TR（4 ms） and TE（1.5 ms）, partial echo sampling, in which central part of k-space is updated more frequently than the peripheral part. TRICKS pre-contrast mask 3D images are firstly scanned, and then the bolus injecting of Gd-DTPA, 15-20 sequential 3D images are acquired. The reconstructed 3D images, subtraction of contrast 3D images with mask images, are conceptually similar to a catheter-based intra-arterial digital subtraction angiographic series （DSA）. Thirty patients underwent contrast-enhanced MR angiography using 3D-TRICKS. Results： Totally 12 vertebral arteries were well displayed on TRICKS, in which 7 were normal, 1 demonstrated bilateral vertebral artery stenosis, 4 had unilateral vertebral artery stenosis and 1 was accompanied with the same lateral carotid artery bifurcation stenosis. Four cases of bilateral renal arteries were normal, 1 transplanted kidney artery showed as normal and 1 transplanted kidney artery showed stenosis. 2 cerebral arteries were normal, 1 had sagittal sinus thrombosis and 1 displayed intracranial arteriovenous malformation. 3 pulmonary arteries were normal, 1 showed pulmonary artery thrombosis and 1 revealed pulmonary sequestration＇s abnormal feeding artery and draining vein. One left lower limb fibrolipoma showed feeding artery. One displayed radial-ulnar artery artificial fistula stenosis. One revealed left antebrachium hemangioma. Conclusion： TRICKS can clearly delineate most body vascular system and reveal most vascular abnormality. It possesses convenience and high successful rate, which make it the first choice of displaying most vascular abnormality.

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.

Diagnostic accuracy of dynamic contrast-enhanced magnetic resonance imaging for distinguishing pseudoprogression from glioma recurrence:a meta-analysis

Background:It is crucial to differentiate accurately glioma recurrence and pseudoprogression which have entirely different prognosis and require different treatment strategies.This study aimed to assess the diagnostic accuracy of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)as a tool for distinguishing glioma recurrence and pseudoprogression.Methods:According to particular criteria of inclusion and exclusion,related studies up to May 1,2019,were thoroughly searched from several databases including PubMed,Embase,Cochrane Library,and Chinese biomedical databases.The quality assessment of diagnostic accuracy studies was applied to evaluate the quality of the included studies.By using the"mada"package in R,the heterogeneity,overall sensitivity,specificity,and diagnostic odds ratio were calculated.Moreover,funnel plots were used to visualize and estimate the publication bias in this study.The area under the summary receiver operating characteristic(SROC)curve was computed to display the diagnostic efficiency of DCE-MRI.Results:In the present meta-analysis,a total of 11 studies covering 616 patients were included.The results showed that the pooled sensitivity,specificity,and diagnostic odds ratio were 0.792(95%confidence interval[CI]0.707-0.857),0.779(95%CI 0.715-0.832),and 16.219(97.5%CI 9.123-28.833),respectively.The value of the area under the SROC curve was 0.846.In addition,the SROC curve showed high sensitivities(>0.6)and low false positive rates(<0.5)from most of the included studies,which suggest that the results of our study were reliable.Furthermore,the funnel plot suggested the existence of publication bias.Conclusions:While the DCE-MRI is not the perfect diagnostic tool for distinguishing glioma recurrence and pseudoprogression,it was capable of improving diagnostic accuracy.Hence,further investigations combining DCE-MRI with other imaging modalities are required to establish an efficient diagnostic method for glioma patients.

Application of contrast-enhanced intraoperative ultrasonography in the decision-making about hepatocellular carcinoma operation

AIM:To evaluate the detection and differentiation ability of contrast-enhanced intraoperative ultrasonography(CE-IOUS) in hepatocellular carcinoma(HCC) operations.METHODS:Clinical data of 50 HCC patients were retrospective analyzed.The sensitivity,specificity,false negative and false positive rates of contrast enhanced magnetic resonance imaging(CE-MRI),IOUS and CEIOUS were calculated and compared.Surgical strategy changes due to CE-IOUS were analyzed.RESULTS:Lesions detected by CE-MRI,IOUS and CEIOUS were 60,97 and 85 respectively.The sensitivity,specificity,false negative rate,false positive rate of CEMRI were 98.2%,98.6%,98.6%,60.0%,respectively;for IOUS were 50.0%,90.9%,1.8%,1.4%,respectively;and for CE-IOUS were 1.4%,40.0%,50.0%,9.1%,respectively.The operation strategy of 9(9/50,18.0%) cases was changed according to the results of CE-IOUS.CONCLUSION:Compared with CE-MRI,CE-IOUS performs better in detection and differentiation of small metastasis and regenerative nodules.It plays an important role in the decision-making of HCC operation.