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Background: Lymphovascular invasion (LVI) status plays an important role in treatment decision‐making in rectal cancer (RC). Intravoxel incoherent motion (IVIM) imaging has been shown to detect LVI; however, making better use of IVIM data remains an important issue that needs to be discussed. Purpose: We proposed to explore the best way to use IVIM quantitative parameters and images to construct radiomics models for the noninvasive detection of LVI in RC. Methods: A total of 83 patients (LVI negative (LVI‐): LVI positive (LVI+) = 51:32) with postoperative pathology‐confirmed LVI status in RC were divided into a training group (n = 58) and a validation group (n = 25). Images were acquired from a 3.0 Tesla machine, including oblique axial T2 weighted imaging (T2WI) and IVIM with 11 b values. The ADC, D, D* and f values were measured on IVIM maps. The ROIs of tumors were delineated on T2WI, DWI, ADCmap, and Dmap images, and three mapping methods were used: ROIs_mapping from DWI, ROIs_mapping from ADCmap, and ROIs_mapping from Dmap. Three‐dimensional radiomics features were extracted from the delineated ROIs. Multivariate logistic regression was used for radiomics feature selection. Radiomics models based on different mapping methods were developed. Receiver operating characteristic (ROC) curves, calibration, and decision curve analyses (DCA) were used to evaluate the performance of the models. Results: Model B, which was constructed with radiomics features from ADCmap, Dmap and fmap by "ROIs_mapping from DWI" and T2WI (AUC 0.894), performed better than other models based on single sequence (AUC 0.600‐0.806) and even better than Model A, which was based on "ROIs_mapping from ADC" and T2WI (AUC 0.838). Furthermore, an integrated model was constructed with Model B and the IVIM parameter (f value) with an AUC of 0.920 (95% CI: 0.820‐1.000), which was higher than that of Model B, in the validation group. Conclusions: The integrated model incorporating the radiomics features and IVIM parameters accurately detected LVI of RC. The "ROIs_mapping from DWI" method provided the best results. [ABSTRACT FROM AUTHOR]

Background and Purpose: This study aimed to investigate the clinical value of intravoxel incoherent motion (IVIM) diffusion-weighted imaging in evaluating the brain microstructure and perfusion changes in end-stage renal disease (ESRD) patients.Methods: The routine head MRI sequences and IVIM were performed on 40 ESRD patients and 30 healthy subjects. The IVIM was executed with 10 b-values varying from 0 to 1000 seconds/mm2 . All subjects were evaluated on neuropsychological test. Laboratory tests were conducted for ESRD patients.Results: Compared with the control group, increased slow apparent diffusion coefficient values (ADCslow ) were found in the left frontal lobe, hippocampus, bilateral temporal lobe, and the right occipital lobe (p < .05), and increased fast ADC values (ADCfast ) were found in all regions of interest (all p < .001) in ESRD patients. In ESRD patients, ADCfast in right frontal lobe (p = .041) and insular lobe (p = .045) was negatively correlated with the Montreal Cognitive Assessment score (MoCA), and ADCfast in the right parietal lobe (p = .009) and hippocampus (p = .041) had positive correlation with hemoglobin levels. Using receiver operating characteristics (ROC) analysis, ADCfast in the right frontal lobe, insular lobe, hippocampus, and parietal lobe separately showed fair to good efficacy in differentiating ESRD patients from healthy subjects, with the area under the ROC ranging from .853 to .903.Conclusions: The microstructure and perfusion of the brain were impaired in ESRD patients. ADCfast of the right frontal lobe, insular lobe, hippocampus, and parietal lobe could be effective biomarker for evaluating cognitive impairment in ESRD patients. [ABSTRACT FROM AUTHOR]

Background: Liver disease can develop in repaired tetralogy of Fallot (TOF) from hepatic congestion caused by volume and pressure overload of the right ventricle. Noninvasive assessment of the liver is important for diagnosing and managing children with TOF. Objective: To evaluate subclinical hepatic changes without liver function test abnormality in adolescents with repaired TOF using intravoxel incoherent motion (IVIM) MRI and cardiac MRI findings. Materials and methods: We included 106 young adults (75 with repaired TOF and 31 healthy individuals) in the study. Liver IVIM MRI examinations were performed with 10 b values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800 s/mm2). Two observers measured IVIM MRI parameters D true, D* and f, as well as apparent diffusion coefficient (ADC) values in liver segments 5–8. Results: D* and f values were significantly lower in adolescents with TOF (P = 0.003 vs. P = 0.05, respectively). ADC values were higher in adolescents with TOF (P = 0.005). However, we found no significant difference between adolescents with and without TOF in terms of Dtrue (P = 0.53). There was a significant correlation between f value and right ventricular ejection fraction. The intraclass correlation coefficient (ICC) analysis of the two observers showed substantial-to-excellent agreement for D, f, D true and ADC (0.7, 0.8, 0.9 and 0.8, respectively). Conclusion: The results of our study suggest that impaired microperfusion with increased ADC values in adolescents with repaired TOF reflect hepatic congestion rather than fibrosis. Hepatic congestion characterized by decreased ADC values can be easily differentiated before fibrotic changes occur by using IVIM MRI to assess diffusion and microcapillary perfusion separately. [ABSTRACT FROM AUTHOR]

• Simplified IVIM metrics from MRIs taken during chemoradiation have prognostic value. • Nonenhancing T2-FLAIR regions have important prognostic value. Prediction of early progression in glioblastoma may provide an opportunity to personalize treatment. Simplified intravoxel incoherent motion (IVIM) MRI offers quantitative estimates of diffusion and perfusion metrics. We investigated whether these metrics, during chemoradiation, could predict treatment outcome. 38 patients with newly diagnosed IDH-wildtype glioblastoma undergoing 6-week/30-fraction chemoradiation had standardized post-operative MRIs at baseline (radiation planning), and at the 10th and 20th fractions. Non-overlapping T1-enhancing (T1C) and non-enhancing T2-FLAIR hyperintense regions were independently segmented. Apparent diffusion coefficient (ADC T1C , ADC T2-FLAIR) and perfusion fraction (f T1C , f T2-FLAIR) maps were generated with simplified IVIM modelling. Parameters associated with progression before or after 6.9 months (early vs late progression, respectively), overall survival (OS) and progression-free survival (PFS) were investigated. Higher ADC T2-FLAIR at baseline [Odds Ratio (OR) = 1.06, 95% CI 1.01–1.15, p = 0.025], lower f T2-FLAIR at fraction 10 (OR = 2.11, 95% CI 1.04–4.27, p = 0.018), and lack of increase in ADC T2-FLAIR at fraction 20 compared to baseline (OR = 1.12, 95% CI 1.02–1.22, p = 0.02) were associated with early progression. Combining ADC T2-FLAIR at baseline, f T2-FLAIR at fraction 10, ECOG and MGMT promoter methylation status significantly improved AUC to 90.3% compared to a model with only ECOG and MGMT promoter methylation status (p = 0.001). Using multivariable analysis, neither IVIM metrics were associated with OS but higher f T2-FLAIR at fraction 10 (HR = 0.72, 95% CI 0.56–0.95, p = 0.018) was associated with longer PFS. ADC T2-FLAIR at baseline, its lack of increase from baseline to fraction 20, or f T2-FLAIR at fraction 10 significantly predicted early progression. f T2-FLAIR at fraction 10 was associated with PFS. [ABSTRACT FROM AUTHOR]

Background: The evaluation of the prognosis of gliomas may have great value in individualized treatment. Purpose: To evaluate the value of intravoxel incoherent motion (IVIM) in predicting the survival of patients with astrocytoma and comparing it to apparent diffusion coefficients (ADC). Material and Methods: Sixty patients with pathologically confirmed cerebral astrocytomas underwent IVIM scans before any treatment was performed. Patients were divided into death group and survival group according to a two-year follow-up. ADC and quantitative parameters of IVIM including D, D*, and f were measured. Independent sample t test was used to compare the two groups of parameters. The accuracy of each parameter for two-year survival rate was analyzed by receiver operating characteristic (ROC) curve and Kaplan-Meier survival curves. The correlation between quantitative parameters and survival days was analyzed by Pearson correlation analysis. Results: The ADC, D*, and f values were statistically significant different between the death and the survival groups (P < 0.05). The AUC of the ADC, D*, and f were 0.811, 0.858, and 0.892, respectively. The ADC cut-off value of 0.668 x 10-3 mm²/s corresponded to 82.6% sensitivity and 73% specificity. The D* cut-off value of 3.913 x 10-3 mm²/s corresponded to 78.4% sensitivity and 87% specificity. The f cut-off value of 0.487 corresponded to 83.8% sensitivity and 87% specificity. Significant log rank test was performed for each parameter to predict overall survival (P < 0.05). There was a correlation between ADC (r = 0.625, P = 0.023), D* (r =-0.655, P = 0.012), f (r =-0.725, P = 0.000) and survival days. Conclusion: The D* and f values demonstrated great potential in predicting the two-year survival rate for patients with astrocytoma. [ABSTRACT FROM AUTHOR]

This study aimed to investigate whether amide proton transfer (APT) imaging, compared with intravoxel incoherent motion (IVIM) imaging-derived parameters, can differentiate squamous cell carcinoma of the cervix (SCCC) from the normal cervical stroma and distinguish poorly differentiated SCCC from well-moderately differentiated SCCC. This prospective study enrolled 32 patients, comprising 20 patients with well-moderately differentiated SCCC and 12 patients with poorly differentiated SCCC. 20 healthy volunteers were enrolled as a control group. A bi-exponential model (BEM) analysis was performed to derive ADC, pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D *) and perfusion fraction (f). The APT signal intensity (APT SI), ADC, D , D * and f were measured. The parameters between the groups were compared with independent t -tests. Diagnostic performance was evaluated with a ROC analysis. The APT SI of SCCC (2.92 ± 0.24%) was higher than that of normal cervical stroma (2.72 ± 0.36%) with P = 0.020. The comparison of the AUCs for the diagnosis of SCCC was ADC > f > APT SI > D* > D. A significant difference was found in the APT SI between the well-moderately differentiated SCCC group (2.82 ± 0.15%) and the poorly differentiated SCCC group (3.09 ± 0.27%) with P = 0.006. Except for D (P = 0.012), the ADC, D * and f values were not significantly different between the groups (P > 0.05). The comparison of the AUCs for distinguishing poorly differentiated SCCC was APT SI > D > ADC > D * = f. APT imaging may be a useful technique in the diagnosis and predicting the differentiation of SCCC. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the predictive role of Intravoxel Incoherent Motion Diffusion-Weighted Imaging (IVIM-DWI) parameters on cervical nodal response to chemo-radiotherapy (CRT) of head and neck squamous cell carcinoma (HNSCC).Materials and Methods: Patients with pathologically confirmed HNSCC were included in the present prospective study, having at least one positive cervical lymph node (LN). They received concomitant CRT and underwent three serial IVIM-DWI investigations: before, at mid-treatment and after treatment completion. Tissue diffusion coefficient D, perfusion-related diffusion coefficient D* and perfusion fraction f were calculated by a bi-exponential fit. The two-sided Mann-Whitney rank test was used to compare the imaging parameters of patients with regional failure (RF) and regional control (RC). A p value lower than 0.05 was considered to be statistically significant.Results: Thirty-four patients were accrued. Twenty-four out of 34 LN (70.6%) showed persistent RC after a median follow-up time of 27.6 months (range: 12.0-50.2 months), while ten cases of RF (29.4%) were confirmed with a median time of 6.8 months (range: 1.5-19.5 months). Patients with RC showed significantly lower pre-treatment D values compared to the RF patients (p=0.038). At mid-treatment, the patients with RF showed significantly higher D values (p=0.025), and exhibited larger percent reductions in f and the product D*×f from the baseline (p=0.008 and <0.001, respectively). No additional information was provided by the examination at the end of treatment.Conclusion: Pre-treatment and mid-treatment IVIM-DWI showed potential for prediction of treatment response of cervical LN in HNSCC patients. [ABSTRACT FROM AUTHOR]

Objective To correlate intravoxel incoherent motion (IVIM) imaging and dynamic contrast-enhanced (DCE) MRI in head and neck squamous cell carcinoma (HNSCC). Methods Forty untreated patients with HNSCC were included retrospectively in the study. Perfusion fraction f , diffusion coefficient D and perfusion-related diffusion coefficient D * were extracted by bi-exponential fitting of IVIM data. Semi-quantitative DCE-MRI parameters, including positive enhancement integral (PEI) and maximum slope of increase (MSI), were calculated. The relationships between all variables were assessed by Spearman's test for correlation. Results 27 primary tumors (PTs) and 23 lymph nodes (LNs) were analyzed. The residual sum of squares (RSS), used to assess the fit quality, was significantly different between PTs and LNs, with the last showing lower values. In LNs, D * and the product D * × f were positively related to both nPEI and nMSI, while no significant correlation was found in PTs. Conclusion Evident relationships between D * and D * × f and DCE-MRI perfusion measurements were found in LNs, while no significant association emerged in PTs. This presumably is due to the poorer agreement between the experimental data and curve fitting for PTs, as compared to LNs. Additional work is warranted to improve the reliability of the IVIM parameter estimations in primary HNSCCs. [ABSTRACT FROM AUTHOR]

Abstract: The intravoxel incoherent motion (IVIM) theory provides a framework for the separation of perfusion and diffusion effects in diffusion-weighted imaging (DWI). To measure the three free IVIM parameters, DWIs with several diffusion weightings b must be acquired. To date, the used b value distributions are chosen heuristically and vary greatly among researchers. In this work, optimal b value distributions for the three parameter fit are determined using Monte-Carlo simulations for the measurement of a low, medium and high IVIM perfusion regime. The first 16 b values of a b value distribution, which was optimized to be appropriate for all three regimes, are {0, 40, 1000, 240, 10, 750, 90, 390, 170, 10, 620, 210, 100, 0, 530 and 970} in units of seconds per square meter. This distribution performed well for all organs and outperformed a distribution frequently used in the literature. In case of limited acquisition time, the b values should be chosen in the given order, but at least 10 b values should be used for current clinical settings. The overall parameter estimation quality depends strongly and nonlinearly on the signal-to-noise ratio (SNR): it is essential that the SNR is considerably higher than a critical SNR. This critical SNR is about 8 for medium and high IVIM perfusion and 50 for the low IVIM perfusion regime. Initial in vivo IVIM measurements were performed in the abdomen and were in keeping with the numerically simulated results. [Copyright &y& Elsevier]

• Bayesian inference for intravoxel incoherent motion magnetic resonance imaging parameters combining a segmented likelihood with hierarchical and spatial priors. • Performance assessment in realistic numerical brain phantom simulations. • In-vivo mapping of perfusion and diffusion in brains of cancer and acute stroke patients with improved contrast-to-noise ratio. [Display omitted] The intravoxel incoherent motion (IVIM) model allows to map diffusion (D) and perfusion-related parameters (F and D*). Parameter estimation is, however, error-prone due to the non-linearity of the signal model, the limited signal-to-noise ratio (SNR) and the small volume fraction of perfusion in the in-vivo brain. In the present work, the performance of Bayesian inference was examined in the presence of brain pathologies characterized by hypo- and hyperperfusion. In particular, a hierarchical and a spatial prior were combined. Performance was compared relative to conventional segmented least squares regression, hierarchical prior only (non-segmented and segmented data likelihoods) and a deep learning approach. Realistic numerical brain IVIM simulations were conducted to assess errors relative to ground truth. In-vivo , data of 11 central nervous system cancer patients and 9 patients with acute stroke were acquired. The proposed method yielded reduced error in simulations for both the cancer and acute stroke scenarios compared to other methods across the whole investigated SNR range. The contrast-to-noise ratio of the proposed method was better or on par compared to the other techniques in-vivo. The proposed Bayesian approach hence improves IVIM parameter estimation in brain cancer and acute stroke. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the relationships between imaging parameters derived from intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and HPV status in oropharyngeal squamous cell carcinoma (OPSCC).Materials and Methods: 73 patients with a new diagnosis of OPSCC were enrolled in the present study. MRI including IVIM-DWI with nine b value (range 0-800 s/mm2) was acquired in all patients. Primary tumor (PT) and the largest metastatic lymph node (LN), if present, were volumetrically contoured and the tissue diffusion coefficient Dt, perfusion fraction f and perfusion-related diffusion coefficient D* were estimated by a bi-exponential fit. The apparent diffusion coefficient (ADC) was also estimated by a mono-exponential fit. The predictive power of the most relevant patient/tumor characteristics and image-based features in determining the HPV status was assessed.Results: 67 PTs and 67 metastatic LNs were analyzed. Significant differences in ADC and Dt values among HPV-positive and HPV-negative patients were found for PTs (p = 0.003 and p < 0.001, respectively), while a trend toward significance in Dt was reported for LNs (p = 0.066). The perfusion-related parameters, f, D* and D*× f, were not related to HPV status. The best predictive model for HPV positivity was obtained combining alcohol intake and smoke habits with Dt values of PTs (accuracy = 80.8%, sensitivity = 85.7%, specificity = 64.7%).Conclusion: Significant correlations were found between IVIM-DWI and HPV status in OPSCCs. The perfusion-free diffusion coefficient, Dt, may better reflect the HPV-related tumor differences compared to ADC, whereas the perfusion-related parameters were not able to reliably discriminate HPV-positive from HPV-negative OPSCC. [ABSTRACT FROM AUTHOR]

Background: Intravoxel incoherent motion magnetic resonance imaging (IVIM) enables non-invasive measurement of brain perfusion. Purpose: To investigate whether IVIM could be used to evaluate the hemodynamic disturbance of Moyamoya disease (MMD) by comparison with the gold-standard 15O-gas positron emission tomography (PET) method. Material and Methods: Ten consecutive patients with MMD (six women; mean age = 42.8 years) and 10 age-matched healthy controls were evaluated by diffusion-weighted images with 12 different b values in the range of 0–900 s/mm2 and 15O-gas PET. Tomographic maps of IVIM parameters, perfusion fraction (f), pseudo-diffusion coefficient (D*), and f・D*, as well as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps obtained with PET, were normalized and hemispheric gray and white matter values were calculated. IVIM parametric values were compared with PET parameters and with clinically assessed disease severity. Results: There was significant correlation between D* and MTT (r = –0.74, P < 0.001) and between f・D* and CBF (r = 0.52, P = 0.02) in the cortical areas. The f values in the white matter were significantly higher in symptomatic MMD patients than in healthy controls (P = 0.01). Conclusion: IVIM may be used to non-invasively investigate cerebral hemodynamic impairment in patients with MMD. Further evaluation is needed to establish IVIM usage in clinical settings. [ABSTRACT FROM AUTHOR]