Time-signal Intensity Curve Research Articles

Application Value of Magnetic Resonance Perfusion Imaging in the Early Diagnosis of Rat Hepatic Fibrosis.

Objective To assess the application value of perfusion-weighted imaging (PWI) in early diagnosis, quantitation, and hepatic fibrosis staging by analyzing the related parameters in hepatic fibrosis. Methods A total of 60 rats were randomly divided into the hepatic fibrosis and control groups, and carbon tetrachloride (CCL4) was used to establish the liver fibrosis model. All rats underwent PWI examination, and the trend of the time-signal intensity curve (TIC, automatically generated by the software) was observed. Also, the perfusion parameters, maximum signal reduction ratio (SRRmax), time to peak (TTP), and mean transit time (MTT), were analyzed and compared with pathological staging. Results The TIC curve was characterized by slow wash-in and wash-out with a low and wide peak. The PWI perfusion parameters were statistically significant in specific groups (P < 0.05): SRRmax values (control group and F3, F4), TTP, and MTT values (control group and F2–F4, F1 and F3, F1 and F4, and F2 and F4 in addition to TTP values for F1 and F2). Pearson's correlation analysis showed a negative correlation of SRRmax with hepatic fibrosis stage (r = −0.439, P < 0.05), while TTP and MTT values were positively correlated with hepatic fibrosis stage (TTP, r = 0.798; MTT, r = 0.647; all P < 0.001). Conclusions PWI perfusion parameters reflect the degree of hepatic fibrosis, especially TTP and MTT, and PWI is recommended for the early diagnosis of liver fibrosis for timely intervention and treatment of the disease and delaying its progression.

Application value of MRI examination in classification diagnosis of rectal mucinous adenocarcinoma

Objective To investigate the application value of magnetic resonance imaging (MRI) in the classification diagnosis of rectal mucinous adenocarcinoma. Methods The retrospective and descriptive study was conducted. The clinical data of 74 patients with rectal mucinous adenocarcinoma who were admitted to Chongqing Traditional Chinese Medicine Hospital from July 2009 and February 2019 were collected. There were 40 males and 34 females, aged (46±8)years, with a range from 32 to 82 years. Among the 74 patients, 41 were simple mucinous adenocarcinoma, 26 were partial mucinous adenocarcinoma, and 7 were focal or small foci mucinous adenocarcinoma. All patients underwent MRI plain scan and dynamic enhanced scan. Observation indicators: (1) morphology of rectal mucinous adenocarcinoma; (2) the lesion margin of rectal mucinous adenocarcinoma; (3) the value of apparent diffusion coefficient (ADC) of rectal mucinous adenocarcinoma; (4) internal enhancement features of rectal mucinous adenocarcinoma; (5) timesignal intensity curve of rectal mucinous adenocarcinoma. Measurement data with normal distribution were represented as Mean±SD, and count data were described as absolute numbers. Results (1) Morphology of rectal mucinous adenocarcinoma: 74 patients had different morphological changes. Among the 41 cases of simple mucinous adenocarcinoma, 22 were oval, 8 were round, and 11 were irregular. Among the 26 patients with partial mucinous adenocarcinoma, 15 were oval, 8 were round and 3 were irregular. Among the 7 patients with focal or small foci mucinous adenocarcinoma, 2 were oval, 1 was round and 4 were irregular. (2) The lesion margin of rectal mucinous adenocarcinoma: the lesion margin of 74 patients was mainly unclear and irregular. Among the 41 cases of simple mucinous adenocarcinoma, 32 had unclear and irregular margin, 7 had clear margin, and 2 had unclear margin combined with fissure. Among the 26 cases of partial mucinous adenocarcinoma, 20 had unclear margin combined with fissure, 5 had unclear margin and irregular margin, and 1 had clear margin. Among the 7 patients with focal or small foci mucinous adenocarcinoma, 5 had unclear or irregular margin, 1 had unclear or irregular margin, and 1 had clear margin. (3) The value of ADC of rectal mucinous adenocarcinoma: diffusion weighted imaging of 74 patients showed diffused limited changes. The average ADC value was (1.24±0.23)×10-3 mm2/s of 41 patients with simple mucinous adenocarcinoma, (0.91±0.42)×10-3 mm2/s of 26 patients with partial mucinous adenocarcinoma, and (1.07±0.24)×10-3 mm2/s of 7 patients with focal or small mucinous adenocarcinoma. (4) Internal enhancement features of rectal mucinous adenocarcinoma: 74 patients showed delayed heterogeneous enhancement and marginal enhancement. Among 41 cases of simple mucinous adenocarcinoma, 24 showed delayed heterogeneous enhancement, 17 showed marginal enhancement, and none showed homogeneous enhancement. Among 26 patients with partial mucinous adenocarcinoma, 20 showed marginal enhancement, 6 showed homogeneous enhancement, and none showed heterogeneous enhancement. All the 7 cases of focal or small foci mucinous adenocarcinoma showed heterogeneous enhancement. (5) Timesignal intensity curve of rectal mucinous adenocarcinoma: 74 patients showed mainly outflow type in the timesignal intensity curve. Among the 41 cases of simple mucinous adenocarcinoma, 22 presented progressive curve, 12 presented platform type, and 7 presented outflow type. Among the 26 patients with partial mucinous adenocarcinoma, 17 presented outflow type, 8 presented platform type, and 1 presented progressive type. Among the 7 patients with focal and small forci mucinous adenocarcinoma, 4 presented outflow type, 2 presented platform type, and 1 presented progressive type. Conclusions MRI findings show different results for different types of rectal mucinous adenocarcinoma. A correct understanding of the MRI features of different types of rectal mucinous adenocarcinoma is helpful for the classification diagnosis of rectal mucinous adenocarcinoma. Key words: Rectal neoplasms; Rectal mucinous adenocarcinoma; Mucous lake; Magnetic resonance imaging

Radiomics Analysis of Dynamic Contrast-Enhanced Magnetic Resonance Imaging for the Prediction of Sentinel Lymph Node Metastasis in Breast Cancer.

Purpose: To investigate whether a combination of radiomics and automatic machine learning applied to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of primary breast cancer can non-invasively predict axillary sentinel lymph node (SLN) metastasis.Methods: 62 patients who received a DCE-MRI breast scan were enrolled. Tumor resection and sentinel lymph node (SLN) biopsy were performed within 1 week after the DCE-MRI examination. According to the time signal intensity curve, the volumes of interest (VOIs) were delineated on the whole tumor in the images with the strongest enhanced phase. Datasets were randomly divided into two sets including a training set (~80%) and a validation set (~20%). A total of 1,409 quantitative imaging features were extracted from each VOI. The select K best and least absolute shrinkage and selection operator (Lasso) were used to obtain the optimal features. Three classification models based on the logistic regression (LR), XGboost, and support vector machine (SVM) classifiers were constructed. Receiver Operating Curve (ROC) analysis was used to analyze the prediction performance of the models. Both feature selection and models construction were firstly performed in the training set, then were further tested in the validation set by the same thresholds.Results: There is no significant difference between all clinical and pathological variables in breast cancer patients with and without SLN metastasis (P > 0.05), except histological grade (P = 0.03). Six features were obtained as optimal features for models construction. In the validation set, with respect to the accuracy and MSE, the SVM demonstrated the highest performance, with an accuracy, AUC, sensitivity (for positive SLN), specificity (for positive SLN) and Mean Squared Error (MSE) of 0.85, 0.83, 0.71, 1, 0.26, respectively.Conclusions: We demonstrated the feasibility of combining artificial intelligence and radiomics from DCE-MRI of primary tumors to predict axillary SLN metastasis in breast cancer. This non-invasive approach could be very promising in application.

Cardiac Magnetic Resonance for Evaluating Nonculprit Lesions After Myocardial Infarction: Comparison With Fractional Flow Reserve

ObjectivesThis study sought to determine the agreement between cardiac magnetic resonance (CMR) imaging and invasive measurements of fractional flow reserve (FFR) in the evaluation of nonculprit lesions after ST-segment elevation myocardial infarction (STEMI). In addition, we investigated whether fully quantitative analysis of myocardial perfusion is superior to semiquantitative and visual analysis. BackgroundThe agreement between CMR and FFR in the evaluation of nonculprit lesions in patients with STEMI with multivessel disease is unknown. MethodsSeventy-seven patients with STEMI with at least 1 intermediate (diameter stenosis 50% to 90%) nonculprit lesion underwent CMR and invasive coronary angiography in conjunction with FFR measurements at 1 month after primary intervention. The imaging protocol included stress and rest perfusion, cine imaging, and late gadolinium enhancement. Fully quantitative, semiquantitative, and visual analysis of myocardial perfusion were compared against a reference of FFR. Hemodynamically obstructive was defined as FFR ≤0.80. ResultsHemodynamically obstructive nonculprit lesions were present in 31 (40%) patients. Visual analysis displayed an area under the curve (AUC) of 0.74 (95% confidence interval [CI]: 0.62 to 0.83), with a sensitivity of 73% and a specificity of 70%. For semiquantitative analysis, the relative upslope of the stress signal intensity time curve and the relative upslope derived myocardial flow reserve had respective AUCs of 0.66 (95% CI: 0.54 to 0.77) and 0.71 (95% CI: 0.59 to 0.81). Fully quantitative analysis did not augment diagnostic performance (all p > 0.05). Stress myocardial blood flow displayed an AUC of 0.76 (95% CI: 0.64 to 0.85), with a sensitivity of 69% and a specificity of 77%. Similarly, MFR displayed an AUC of 0.82 (95% CI: 0.71 to 0.90), with a sensitivity of 82% and a specificity of 71%. ConclusionsCMR and FFR have moderate-good agreement in the evaluation of nonculprit lesions in patients with STEMI with multivessel disease. Fully quantitative, semiquantitative, and visual analysis yield similar diagnostic performance.

Radiological and clinical findings in sclerosing adenosis of the breast.

To study the imaging and clinical features of breast sclerosing adenosis (SA), and to enhance the recognition of this disease, as well as to help the clinic to give a correct diagnosis.Imaging findings were retrospectively reviewed in 47 women with SA lesions confirmed by pathology (including 39 cases of mammography, 40 cases of ultrasound [US], and 34 cases magnetic resonance imaging [MRI]).Of 47 patients confirmed with SA, 18 cases were pure SA, and 29 cases coexist with other proliferative lesions and malignancies; the maximum diameter of SA lesions was 0.5 to 3.5 cm with an average of 1.6 cm. On the mammogram of 39 SA cases, the percentage of architectural distortion, calcifications, mass/nodular, asymmetric density, and mass combining with calcifications were 30.8%, 23.1%, 17.9%, 12.8%, and 7.7%, respectively; and 3 cases had no abnormal findings. On the sonogram (excluding 5 normal finding cases), the majority of lesions showed regular shaped (57.1%), well defined margined (60.0%), heterogenous low echoed (71.4%) nodulus. 85.3% lesions showed high signal on T2-weighted images, and all lesions were enhanced markedly, including 82.4% lesions appearing mass-like enhancement (17 star-shaped enhanced masses included); and the percentage of the time-signal intensity curve in type 1, type 2, and type 3 were 52.9%, 41.2%, and 5.9%, respectively. If the category breast imaging-reporting and data system ≥4b was considered to be a suspicious malignant lesion, the misdiagnostic rates of mammography, US, and MRI would be 17.9%, 17.5%, and 35.3%, respectively.The SA lesions are small and can occur with other diseases histologically. The majority of SA lesions showed distortion or calcifications on mammograms, low echo-level nodules with heterogenous echo on US and mass-like lesion with or without star shape on enhanced MRI.

Added value of histogram analysis of apparent diffusion coefficient maps for differentiating triple-negative breast cancer from other subtypes of breast cancer on standard MRI.

BackgroundTriple-negative breast cancers generally occur in young women with remarkable potential to be aggressive. It will be of great help to detect this subtype of tumor early. To retrospectively evaluate the performance of histogram analysis of apparent diffusion coefficient (ADC) maps in distinguishing triple-negative breast cancer (TNBC) from other subtypes of breast cancer (non-TNBC), when combined with magnetic resonance imaging (MRI) features.Materials and methodsFrom February 2014 to December 2018, 192 patients were included in this study taking preoperative standard MRI (s-MRI) and DWI. Seventy-six of them were pathologically confirmed with TNBC and rest 116 with other subtypes. First, their clinical-pathological features and morphological characteristics on MRI were assessed, including tumor size, foci quantity, tumor shape, margin, internal enhancement, and time-signal intensity curve types, in addition to the signal intensity on T2-weighted images. Second, whole-lesion apparent diffusion coefficient (ADC) histogram analysis was executed. Finally, both univariate and multivariate regression analyses were applied to identify the most useful variables in separating TNBCs from non-TNBCs, and then their effects were evaluated following receiver operating characteristic curve analysis.ResultMultivariate regression analysis indicated that circumscribed margin, rim enhancement, and ADC90 were important predictors for TNBC. Increased area under curve (AUC) and improved specificity can be obtained when combined s-MRI and DWI (circumscribed margin+rim enhancement+ADC90>1.47×10−3 mm2/s) is taken as the criterion, other than s-MRI (circumscribed margin+rim enhancement) alone (s-MRI+DWI vs s-MRI; AUC, 0.833 vs 0.797; specificity, 98.3% vs 89.7%; sensitivity, 68.4% vs 69.7%).ConclusionCircumscribed margin and rim enhancement on s-MRI and ADC90 are three important elements in detecting TNBC, while ADC histogram analysis can provide additional value in this detection.

The correlation between functional magnetic resonance imaging features and expression of Her-2 in breast cancer

Objective: To explore the correlation between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), magnetic resonance diffusion-weighted imaging (DWI) images of breast cancer and human epidermal growth factor receptor-2 (Her-2) expression. Methods: A retrospective analysis of 84 patients with breast cancer confirmed by biopsy from January 2012 to December 2016 in Zhejiang University Lishui Hospital was conducted. The data of DCE-MRI, DWI scanning were collected before surgery and Her-2 was detected by immunohistochemistry (IHC). Then, all the patients were divided into Her-2 positive group and Her-2 negative group according to Her-2 expression. There were 44 cases in the Her-2 positive group and 40 cases in the Her-2 negative group. The differences in the characteristics of the lesion morphology, time-signal intensity curve (TIC), early enhancement rate and apparent diffusion coefficient (ADC) were compared, and their correlation with Her-2 expression was analyzed. Results: Of the 84 lesions, 12 were orthotopic ductal carcinoma, 6 were lobular carcinoma, and 66 were invasive ductal carcinoma. There were significant differences in lesion morphology (P=0.012) and TIC curve morphology (P=0.038) between Her-2 positive group and negative group. At the same time, the early enhancement rate (P=0.012) and ADC value (P=0.038) of Her-2 positive group were significantly higher than those of negative group. Except morphology of segmental lesions and TIC curve morphology, other characteristic parameters were correlated to Her-2 (all P<0.05). The correlation coefficients between early enhancement rate, ADC value and Her-2 expression were as high as 0.758 and 0.809 (all P<0.05). Conclusions: The morphology of breast cancer lesions, time-signal intensity curve, early enhancement rate and ADC value are all correlated with Her-2 expression.The early enhancement rate and ADC value are significantly positively correlated with Her-2 expression.

Differential diagnosis of nasopharyngeal carcinoma and nasopharyngeal lymphoma based on DCE-MRI and RESOLVE-DWI

To explore the utility of dynamic contrast-enhanced MRI (DCE-MRI) and readout-segmented diffusion-weighted imaging (RESOLVE-DWI) in the differentiation of nasopharyngeal carcinoma (NPC) and nasopharyngeal lymphoma (NPL). Sixty-two patients with NPC and 39 patients with NPL who underwent DCE-MRI and RESOLVE-DWI examinations were evaluated. The time signal-intensity curve (TIC) types, time to peak (TTP), enhancement peak (EP), maximum contrast enhancement ratio (MCER), washout ratio (WR), apparent diffusion coefficient (ADC), and relative ADC (rADC) values were calculated. Statistical analysis between the two groups was performed to determine the statistical significance of each parameter. Receiver operating characteristic (ROC) curve analysis and binary logistic regression analysis were used to assess the diagnostic ability of single and combined metrics for distinguishing NPC from NPL. The most common TIC curve was type III in patients with NPC (n = 26), while the majority of the curves were types I (n = 14) and II (n = 19) in patients with NPL. TTP, EP, MCER, ADC, and rADC were statistically significantly different between NPCs and NPLs (p < 0.05). Among these factors, ADC revealed the most reliable diagnostic performance, followed by rADC, TTP, MCER, and EP. Moreover, the diagnostic efficiency of the combined DCE-MRI parameters was higher than that of TTP, MCER, and EP each alone. In addition, the combination of all DCE-MRI and DWI parameters together demonstrated the highest diagnostic efficiency (area under the curve = 0.961). However, none of the parameters was significantly different between keratinising NPC and non-keratinising NPC or between NK/T lymphoma and diffuse large B cell lymphoma (all p > 0.05). DCE-MRI and RESOLVE-DWI are effective in differentiating NPC from NPL. • RESOLVE offers high image quality in the head and neck regions. • Dynamic contrast-enhanced MRI and RESOLVE-DWI help clinicians to make the differential diagnosis between NPC and NPL. • The combination of all the DCE-MRI and DWI parameters together demonstrated the highest diagnostic efficiency compared with each parameter alone.

Breast MRI in the era of diffusion weighted imaging: do we still need signal-intensity time curves?

ObjectiveDynamic contrast-enhanced imaging of the initial (IP) and delayed phase (DP) is an integral part of any clinical breast MRI protocol. Furthermore, DWI is increasingly used as an add-on sequence by the breast-imaging community. We investigated whether DWI could be used as a substitute DP.Material and methodsOne hundred thirty-two consecutive patients with equivocal or suspicious findings at ultrasound and/or mammography received a full diagnostic breast MRI according to international recommendations. Histopathological verification served as reference standard. We evaluated three sections of the MRI protocol: IP, DP, and apparent diffusion coefficient (ADC) maps derived from DWI. Circular ROIs (regions of interest, mean size 5–10 mm2) were drawn into the enhancing parts of the lesion (first postcontrast). ROIs were transferred to the corresponding location on ADC maps and IP and DP images. Mean ROI values were investigated signal intensity (SI): (1) Initial-phase enhancement = (SI(IP) − SI(precontrast))/SI(precontrast); (2) Delayed-phase enhancement = (SI(DP) − SI(IP))/SI(IP); (3) ADC. Multiparametric combinations were computed using logistic regression analysis: (1) IP+: Initial-phase enhancement and ADC; (2) Curve: Initial-phase enhancement and delayed-phase enhancement; (3) Curve+: Curve and ADC. The diagnostic performances of these feature combinations to diagnose malignancy were compared by the area under the receiver-operating characteristics curve (AUC).ResultsOne hundred thirty-two patients (age: mean = 57.1 years, range 23–83 years) with 145 lesions were included (malignant/benign 101/44). IP+ (AUC = 0.877) outperformed Curve (AUC = 0.788, p = 0.03). Curve+ was not superior to IP+ (p = 1).ConclusionDWI could substitute DP. Because DWI is typically used as an add-on to IP and DP, our results might help to abbreviate and to simplify current practice of breast MRI.Key Points• DWI provides similar but superior diagnostic information for diagnosis of malignancy in enhancing breast lesions compared to DP.• Adding DP to DWI does not provide incremental information to distinguish benign from malignant lesions.• DWI could substitute DP. As DWI is typically used as an add-on to IP and DP, our findings might help to abbreviate and to simplify current breast MRI practice.

P068 The utility of contrast-enhanced trans-abdominal ultrasound in the assessment of ileal Crohn's disease

BACKGROUND: While ileo-colonoscopy remains the gold standard for luminal evaluation of Crohn’s ileitis, repeated colonoscopies to reassess disease activity can be inconvenient (prep, lost time from work) and put the patient at additional procedure risk and increase health care cost. MRI and CT enterography can be used to assess ileal disease, but the tests involve contrast use, radiation exposure, and are lengthy and costly. Contrast-enhanced ultrasound (CEUS) has been promoted in Europe and Asia as a promising tool for assessment of disease activity with lower cost and no radiation exposure. METHODS: This is a prospective study currently enrolling patients with active Crohn's ileitis. All patients underwent evaluation with ileo-colonoscopy and serum inflammatory marker (CRP). Subsequently, all patients underwent CEUS by an independent radiologist who was blinded to the endoscopy results. Ultrasound contrast agent sulfur hexafluoride with gas-filled microbubbles was used (4.8 mL of IV Lumason, Bracco Diagnostics Inc), with real-time visualization of bowel wall microvascularization and perienteric tissue. Bowel wall thickness was measured and a time-signal intensity curve was obtained after calculating the peak enhancement and area under the curve. Prior groups (1) used a cut off point of 18.2 dB for moderate activity and 23.0 dB for severe activity. CEUS findings were compared to the endoscopic findings to assess for correlation in assessing disease activity and severity. RESULTS: Four male patients (age 22–65, 3 AA and one Caucasian) with symptomatic Crohns ileitis were enrolled in our study thus far. Patient A had moderate inflammation on CEUS with a peak intensity of 22 dB correlating with Rutgeerts i3 ileitis (large ulcers) above the ileoclonic anastomosis. Patient B had severe inflammation on CEUS with a peak intensity of 27 dB that correlated with moderate to severe ileitis with an inflammatory stricture on endoscopy. Patient C and D both had mild enhancement of distal ileum with a peak intensity of 17 dB; correlating with the findings of aphthous and larger ulcers on endoscopy. Only the 2 patients with a peak intensity of 27 dB had elevated CRP. CONCLUSION(S): In our limited experience, CEUS correlates with endoscopic findings of active ileitis and disease severity in Crohn's patients. With further patients enrollment and follow up, we aim to confirm this finding and to assess whether CEUS imaging can also evaluate inactive ileitis in treated Crohn's patients.

Blood Oxygen Level–Dependent Response Changes in the Ipsilateral Primary Somatosensory Cortex and Thalamus of Patients With Moyamoya Disease During Median Nerve Electrical Stimulation

The objective of this study was to investigate the changes in the blood oxygen level-dependent (BOLD) response in the ipsilateral primary somatosensory cortex (SI) and thalamus of patients with moyamoya disease (MMD) during sensory stimulation. Sixty-four MMD patients, and 15 healthy volunteers were enrolled. Thirty-three MMD patients exhibited paroxysmal numbness or hypoesthesia in the unilateral limbs. Fifteen patients with acroparesthesia underwent unilateral encephaloduroarteriosynangiosis (EDAS). All volunteers underwent BOLD functional magnetic resonance imaging (BOLD-fMRI) under median nerve electrical stimulation (MNES). Blood oxygen level-dependent fMRI data were processed to obtain time-signal intensity curves in the activation areas of the bilateral SI and thalamus. Processed dynamic susceptibility contrast-enhanced magnetic resonance imaging data were used to measure the time to peak of the BOLD response in the regions of interest, including the bilateral SI, thalamus, and cerebellum. Changes in the time-signal intensity curve-related hemodynamic parameters in the ipsilateral SI and thalamus were examined between healthy controls, nonacroparesthesia patients, and asymptomatic and symptomatic sides of unilateral acroparesthesia patients during MNES. Changes in these parameters in MMD patients before and after EDAS were examined. Compared with healthy volunteers, 3 groups of MMD patients exhibited an increased peak of the positive BOLD response in the ipsilateral thalamus during MNES (0.65 ± 0.24 vs 0.79 ± 0.35, 0.94 ± 0.57, and 0.89 ± 0.50; P = 0.0335). The positive response peak in the ipsilateral SI markedly increased in MMD patients with acroparesthesia during MNES on the asymptomatic side (0.56 ± 0.37 vs 0.38 ± 0.27, P = 0.0243). The time to peak negative response in the ipsilateral SI was prolonged during MNES on the symptomatic side after EDAS (12.14 ± 8.90 seconds vs 18.86 ± 9.20 seconds, P = 0.0201). During sensory stimulation treatment, BOLD response changes occurred in the ipsilateral SI and thalamus of MMD patients. These changes enabled the contralateral hemisphere of the brain to better deal with sensory stimuli.

Comparative Study of Dynamic Susceptibility Contrast Perfusion MR Images between Warthin&amp;apos;s Tumor and Malignant Parotid Tumors

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

Prediction of IDH genotype in gliomas with dynamic susceptibility contrast perfusion MR imaging using an explainable recurrent neural network.

The aim of this study was to predict isocitrate dehydrogenase (IDH) genotypes of gliomas using an interpretable deep learning application for dynamic susceptibility contrast (DSC) perfusion MRI. Four hundred sixty-three patients with gliomas who underwent preoperative MRI were enrolled in the study. All the patients had immunohistopathologic diagnoses of either IDH-wildtype or IDH-mutant gliomas. Tumor subregions were segmented using a convolutional neural network followed by manual correction. DSC perfusion MRI was performed to obtain T2* susceptibility signal intensity-time curves from each subregion of the tumors: enhancing tumor, non-enhancing tumor, peritumoral edema, and whole tumor. These, with arterial input functions, were fed into a neural network as multidimensional inputs. A convolutional long short-term memory model with an attention mechanism was developed to predict IDH genotypes. Receiver operating characteristics analysis was performed to evaluate the model. The IDH genotype predictions had an accuracy, sensitivity, and specificity of 92.8%, 92.6%, and 93.1%, respectively, in the validation set (area under the curve [AUC], 0.98; 95% confidence interval [CI], 0.969-0.991) and 91.7%, 92.1%, and 91.5%, respectively, in the test set (AUC, 0.95; 95% CI, 0.898-0.982). In temporal feature analysis, T2* susceptibility signal intensity-time curves obtained from DSC perfusion MRI with attention weights demonstrated high attention on the combination of the end of the pre-contrast baseline, up/downslopes of signal drops, and/or post-bolus plateaus for the curves used to predict IDH genotype. We developed an explainable recurrent neural network model based on DSC perfusion MRI to predict IDH genotypes in gliomas.

Differential diagnosis of different types of tumors in the parotid gland by 3.0T magnetic resonance dynamic enhanced imaging and diffusion-weighted imaging

Objective To investigate the differential diagnosis of benign and malignant parotid tumors by 3.0T MR dynamic enhancement (DCE-MRI) and diffusion-weighted MR imaging (DWI). Methods A retrospective analysis of 56 cases of parotid tumors in our hospital in May-2017 May 2016, and the integration of all patients with MRI and DWI data. The ADC value, the time signal intensity curve (TIC) and the quantitative parameters of the lesions were statistically analyzed, and the parameters of the diagnosis of malignant tumors were calculated by the receiver operating characteristic (ROC) curve. Results 86.67% (13/15) of pleomorphic adenoma in benign tumors showed A curve (Persistent), 13.23% (2/15) showed C curve (Washout), 73.07% (19/26) in adenolymphoma was B curve (Plateau), and the other 26.93% (9/26) was C type. In malignant tumor, 90% (9/10) presented a C curve and 10% (1/10) presented a B curve. The TIC types of benign and malignant parotid tumors were significantly different (P<0.05). There was a significant difference in ADC values between malignant tumors and pleomorphic adenoma, other benign tumors. Conclusion DCE-MRI and diffusion-weighted imaging have high clinical value in the differential diagnosis of benign and malignant tumors in the parotid gland, which may be useful for the diagnosis and treatment plan of parotid gland tumors. Key words: Parotid gland tumor; Dynamic enhancement; Quantitative analysis; Magnetic resonance imaging

Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a Diagnostic Tool in the Assessment of Tumour Angiogenesis in Urinary Bladder Cancer

PurposeThe aim of study is to assess the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and correlation with tumour angiogenesis in evaluation of urinary bladder cancer. Material and MethodsThe study included 81 patients with recent presumed diagnosis of bladder tumour or who came for follow up after management of histopathologically proven bladder cancer. All had DCE-MRI with time–signal intensity curve. The radiologic results then correlated with the histopathologic results using both haematoxylin and eosin stain and immuno-histochemical staining for localization and evaluation of CD34 immunoreactivity as a detector for the microvessel density (MVD) and tumour angiogenesis. ResultsSeventy-one cases were pathologically proven to be malignant: 41 cases (58%) showed type III time–signal intensity curve (descending); 22 cases (31%) showed type II (plateau); and 8 cases (11%) showed type I (ascending) curve. The sensitivity of DCE-MRI in stage T1 bladder tumour was 80%; in stage T2, it was (90.9%); and in stage T3, it was (96.9%). Overall accuracy of DCE-MRI in tumour staging was 89.5% and P = .001 (significant). Values more than the cutoff value = 76.13 MVD are cystitis with sensitivity (90%), specificity (91%), and P value is .001, which is statistically highly significant. ConclusionThere is a strong positive association between DCE-MRI (staging and washout slope of the time–signal intensity curve) with histopathologic grade, tumour stage, and MVD in bladder cancer. So, DCE-MRI can be used as reliable technique in preoperative predictions of tumour behavior and affect the planning of antiangiogenetic therapy.

Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging for Differentiation Between Parotid Neoplasms

PurposeThis study was designed to evaluate the role of multiparametric magnetic resonance imaging (MRI) for differentiation of parotid gland neoplasms. MethodsProspective study was conducted upon 52 consecutive patients (30 men, 22 women; aged 24–78 years; mean, 51 years) with parotid tumours that underwent multiparametric MRI using combined static MRI, dynamic contrast enhanced (DCE) MRI, and diffusion-weighted imaging (DWI). The static MRI parameter, time signal intensity curves (TIC) derived from DCE-MRI, and apparent diffusion coefficient (ADC) values of parotid tumours were correlated with histopathological findings. ResultsStatic MRI revealed a significant difference between both benign and malignant lesions in regards to margin definition (P < .001) and T2 hypointensity (P < .013), with a diagnostic accuracy 95% and 78.33% respectively. Study of the TIC type on DCE-MRI revealed statistically significant difference between benign and malignant lesions (P < .001) and diagnostic accuracy 96.55%. There was no statistically significant difference (P = .181) between the ADC values of benign and malignant lesions. ROC curve analysis revealed that by using ADC cut-off value of 1 × 10−3 mm2/s had accuracy of 84.62% respectively for differentiating Warthin from malignant tumours that could be modified to higher value (94.28%) by excluding lymphoma from malignant lesions. By using cutoff value of 1.3 × 10−3 mm2/s to differentiate pleomorphic adenoma from malignancy, ROC curve analysis had high accuracy of 97.06%. ConclusionMultiparametric MRI can be used for differentiation of malignant from benign parotid tumours and characterization of some benign parotid tumours.

3 T MR perfusion of solid pancreatic lesions using dynamic contrast-enhanced DISCO sequence: Usefulness of qualitative and quantitative analyses in a pilot study

PurposeTo assess the usefulness of qualitative and quantitative analyses of pancreatic focal diseases by using the dynamic contrast-enhanced Differential Subsampling with Cartesian Ordering (DISCO) sequence at 3 T MR device. Materials and methodsTen patients without pancreatic diseases and twenty-five patients with pathologically confirmed pancreatic focal disease (ductal adenocarcinoma, n = 14; endocrine tumour, n = 8; focal chronic pancreatitis, n = 3), underwent MRI by 3 T-device. Multiphasic contrast-enhanced MR perfusion, consisting of a 3D axial navigator, based free-breathing T1-weighted DISCO sequence, was repeated for 5 min. A dose of 0.1 mL/kg of Gadobutrolo with a 20 mL saline flush was injected at a flow rate of 5 mL/s. Perfusion MRI were processed using a dedicated software package (GeniQ; GE Healthcare), obtaining both a time-signal-intensity curve (TSIC) and perfusion maps for each healthy pancreatic parenchyma and focal disease. The TSIC were grouped into four types according to their shapes and the MR perfusion parameters (Ktrans, Kep, Ve, IAUGC) were calculated.The one-way analysis of variance and the Student's t-test were used to correlate the quantitative and qualitative parameters with the tissue histology. ResultsAll 10 patients with healthy pancreas presented a TSIC-type 1; TSIC-type 2 was observed in all 14 ductal adenocarcinomas and in one neuroendocrine tumour; TSIC-type 3 was recognized in the remaining 7 neuroendocrine neoplasms; TSIC-type 4 was identified in all 3 focal chronic pancreatitis. All perfusion parameters were significantly different (p < 0.0001) for each type of lesion. Furthermore, Ve was also very useful to discriminate between normal and pathological tissues (p = 0.0005). ConclusionQualitative and quantitative analyses of contrast-enhanced 3 T MR perfusion, using the dynamic contrast-enhanced DISCO sequence, could be considered an interesting tool to improve the diagnosis of focal pancreatic diseases, of solid lesions in particular. Further investigations with prospective larger sample studies are required to confirm these preliminary results.

Treatment-related alterations of imaging findings in osteoid osteoma after percutaneous radiofrequency ablation.

We aimed to report the long-term outcomes of osteoid osteoma patients and to determine CT and dynamic contrast-enhanced MR imaging characteristics of radiofrequency ablation (RFA) treatment related changes of osteoid osteoma between follow-up periods. Thirty patients (seven female, 23 male) who underwent CT-guided RFA of osteoid osteoma were included. Follow-up imaging examinations were divided into two subgroups; first (1-3 months) and second (> 6months) periods. Nidus size, calcification, cortical thickening, maximum signal intensity (SImax), time of SImax (Tmax), slope of signal intensity-time (SIT) curves were noted. CT and dynamic MR imaging findings were compared between follow-up periods. Clinical success rate was 100%. The mean of OO nidi size was 5.85 ± 1.98mm before treatment. There was a significant difference for OO nidi sizes between pretreatment and second follow-up period examinations (p = 0.002). SImax and slope of SIT curves of all patients (100%) showed decrease on follow-up MRIs. There was a significant decrease for SImax values between pretreatment and second follow-up period. There was a significant decrease for slope of SIT curves between pretreatment and both follow-up periods. RFA is an effective and safe treatment choice for osteoid osteomas. On follow-up imaging, slope of SIT curve and Tmax have the most important positive predictive value for long-term outcomes and single dynamic contrast-enhanced MRI within first 3months after treatment may be sufficient for symptom-free patients.

Role of Magnetic Resonance Imaging in the Diagnosis of Different Pancreatic Lesions

AbstractBackground: Pancreatic cancer is one of the most lethal human cancers that requires early diagnosis. Ultrasound, CT and MRI are different imaging modalities used for diagnosis of pancreatic masses. Diffusion-Weighted Imaging (DWI) and Time-signal Intensity Curve (TIC) can add to the diagnosis of pancreatic masses.Aim of Study: The aim of this study was to evaluate the role of magnetic resonance imaging in the diagnosis of different pancreatic lesions.Patients and Methods: Twenty-three patients were divided into 4 groups, group A (Acute Pancreatitis) (AP), group B (pancreatic cysts) which subdivided into malignant and benign cysts, group C (adenocarcinoma) and group D (Focal Pancre-atitis) (FP), all patients groups were compared to the control group. MRI protocol included MRI-c (T1WI, T1 Fat Suppres-sion (FS), T2WI, T2FS and IV dynamic contrast study) and DWI which performed on (1.5 Tesla) Magnet Unit General Electric (GE). TIC was obtained from the dynamic study and the results were divided into three patterns of curves.Results: Control group demonstrated type-I TIC, group (A & D) demonstrated type-II and group C demonstrated type-III.The mean Apparent Diffusion Coefficient (ADC) values were significant lower (p<0.001) in (A & C) groups, statically different (p<0.02) between benign and malignant cysts. Stat-ically different (p<0.001) between control and patients' groups. The sensitivity, specificity, accuracy, positive and negative predictive values of DWI and MRI-c were 92.3%, 90%, 91.3%, 92.3%, 90% and 100%, 90%, 95.7%, 92.9%, 100%, respec-tively.Conclusion: DWI and TIC were useful tools in diagnosis, characterization and differentiation between pancreatic lesions.

Can whole-tumor apparent diffusion coefficient histogram analysis be helpful to evaluate breast phyllode tumor grades?

PurposeTo investigate whether whole-tumor apparent diffusion coefficient (ADC) histogram analysis could be helpful to evaluate breast phyllode tumor (PT) grades. Materials and methodsThis institutional review board-approved retrospective study included 56 PTs (23 benign lesions, 22 borderline lesions, and 11 malignant lesions) from August 2011 to November 2017. MRI was performed using a 1.5 T MR system equipped with a 4-channel SENSE breast coil. All cases were divided into two groups, benign PT (BPT) and borderline or malignant PT (BMPT). The conventional MR parameters included age, longest diameter, shape, margin, internal enhancement characteristics, cystic component of the tumor, wall of the cystic component, peritumoral edema on T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and T2WI signal intensity, time-signal intensity curve (TIC) patterns and early-stage enhancement ratio (EER). The ADC values were determined in three different types of regions of interest (ROIs), including a circular ROI (ROI-c), single-slice ROI (ROI-s), and whole-tumor ROI (ROI-w). All ADC values were measured twice by Observer A and B (with a 2-week interval). The Ki-67 index was determined, and cases were classified into a “negative group” (Ki-67<14%) and a “positive group” (Ki-67≥14%). SPSS Statistics V21.0 was used for the statistical analyses. ResultsOur study included 23 cases of BPT and 33 cases of BMPT (including 22 borderline PTs and 11 malignant PTs). Only 23 patients in BMPT group had Ki-67 results, and 17 of these were positive. Regarding conventional MR features, significant differences were observed in the margin (P = 0.011), cystic component (P<0.001), peritumoral edema on T2WI (P<0.001), and cystic wall (P = 0.011) of the PT between the BPT and BMPT groups. Regarding the ADC value, good intraobserver agreement for ROI-c, ROI-s and ROI-w measurements was obtained. For the three different ROIs, the intraclass correlation coefficient (ICC) values were 0.905 for ROI-c (P > 0.05), 0.965 (P > 0.05) for ROI-s and 0.994 (P > 0.05) for ROI-w. ADC parameter indicated that the figure of ROI-s tended to be higher than the ROI-c and ROI-w, while the ROI-c and ROI-w values were similar. However, no significant difference was found in ADC values between the BPT and BMPT groups for ROI-c, ROI-s and mean ROI-w values and the 10th, 25th, 50th and 75th ROI-w. The areas under the ROC curves for the mean ROI-w and the 10th, 25th, 50th and 75th ROI-w were 0.568, 0.613, 0.567, 0.544, and 0.540, respectively. ConclusionBased on the results obtained in our study, the whole-tumor ADC histogram could not improve differentiation of the breast PT grade, while conventional MR images could provide more meaningful information, so morphological characteristics may be valuable than ADC value, and ADC could be used as a supplemental method to differentiate PT grades.