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Objective . The acquisition of diffusion-weighted images for intravoxel incoherent motion (IVIM) imaging is time consuming. This work aims to accelerate the scan through a highly under-sampling diffusion-weighted turbo spin echo PROPELLER (DW-TSE-PROPELLER) scheme and to develop a reconstruction method for accurate IVIM parameter mapping from the under-sampled data. Approach . The proposed under-sampling DW-TSE-PROPELLER scheme for IVIM imaging is that a few blades per b -value are acquired and rotated along the b -value dimension to cover high-frequency information. A physics-informed residual feedback unrolled network (PIRFU-Net) is proposed to directly estimate distortion-free and artifact-free IVIM parametric maps (i.e., the perfusion-free diffusion coefficient D and the perfusion fraction f ) from highly under-sampled DW-TSE-PROPELLER data. PIRFU-Net used an unrolled convolution network to explore data redundancy in the k-q space to remove under-sampling artifacts. An empirical IVIM physical constraint was incorporated into the network to ensure that the signal evolution curves along the b -value follow a bi-exponential decay. The residual between the realistic and estimated measurements was fed into the network to refine the parametric maps. Meanwhile, the use of synthetic training data eliminated the need for genuine DW-TSE-PROPELLER data. Main results . The experimental results show that the DW-TSE-PROPELLER acquisition was six times faster than full k-space coverage PROPELLER acquisition and within a clinically acceptable time. Compared with the state-of-the-art methods, the distortion-free D and f maps estimated by PIRFU-Net were more accurate and had better-preserved tissue boundaries on a simulated human brain and realistic phantom/rat brain/human brain data. Significance . Our proposed method greatly accelerates IVIM imaging. It is capable of directly and simultaneously reconstructing distortion-free, artifact-free, and accurate D and f maps from six-fold under-sampled DW-TSE-PROPELLER data., (© 2023 Institute of Physics and Engineering in Medicine.)

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/mm 2 . 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 (ADC slow ) were found in the left frontal lobe, hippocampus, bilateral temporal lobe, and the right occipital lobe (p < .05), and increased fast ADC values (ADC fast ) were found in all regions of interest (all p < .001) in ESRD patients. In ESRD patients, ADC fast in right frontal lobe (p = .041) and insular lobe (p = .045) was negatively correlated with the Montreal Cognitive Assessment score (MoCA), and ADC fast in the right parietal lobe (p = .009) and hippocampus (p = .041) had positive correlation with hemoglobin levels. Using receiver operating characteristics (ROC) analysis, ADC fast 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. ADC fast of the right frontal lobe, insular lobe, hippocampus, and parietal lobe could be effective biomarker for evaluating cognitive impairment in ESRD patients., (© 2022 American Society of Neuroimaging.)

Background: Central nervous system inflammation is associated with neurodegenerative diseases and is thought to play a part in the pathophysiological cascade leading to cognitive impairment. Madecassoside (MA) has shown potential for the treatment of neuroinflammation. Lipopolysaccharide (LPS) can be used to establish an animal model of cognitive dysfunction induced by neuroinflammation. Intravoxel incoherent motion (IVIM) may potentially provide diffusion and perfusion data., Purpose: To investigate the effect of MA on neurocognitive impairment induced by LPS in rats, and to explore the changes of brain microstructure and microcirculatory perfusion by IVIM imaging., Study Type: Prospective., Population: Thirty-six male Sprague-Dawley rats were randomly divided into six groups (control group, sham operation group, LPS group, low-dose MA group, middle-dose MA group, and high-dose MA group) in a model of neurocognitive impairment induced by LPS (150 μg / 5 μL, 5 μL)., Field Strength/sequence: IVIM-DWI sequence at 3.0T MRI; the scan time was 2 minutes and 17 seconds., Assessment: The escape latency times of a Morris water maze test was used to evaluate the cognitive impairment rat model and the changes of learning ability of rats treated with different doses of MA (30 mg/kg, 60 mg/kg, 120 mg/kg). A GE postprocessing workstation (adw 4.5) was used to analyze the changes of each parameter (f value, D value, and D* value) in the IVIM data of each group., Statistical Tests: All the data were analyzed by one-way and two-way analysis of variance (ANOVA)., Results: The escape latency of the LPS group was significantly longer than the sham group (P = 0.05, 0.001, 0.006, and 0.042, respectively), and the high-dose group was significantly shorter than the LPS group on the sixth day (P = 0.034). Compared with the control group, the D values and f values of cerebral cortex and hippocampus were decreased significantly in the LPS group (P = 0.043 and 0.003; P = 0.029 and 0.016, respectively). With the increasing dose of MA, the D and f values of hippocampus and cortex increased, and there was a significant difference between the high-dose MA group and LPS group (D values: P = 0.038, 0.036; f values: P = 0.048, 0.039, respectively) DATA CONCLUSION: MA can improve the cognitive impairment induced by LPS by reducing neuroinflammation, and the changes of microcirculation and microperfusion in the brain tissue of these rats can be detected by IVIM imaging., Level of Evidence: 1 Technical Efficacy Stage: 4 J. Magn. Reson. Imaging 2020;51:1836-1843., (© 2019 International Society for Magnetic Resonance in Medicine.)

Purpose: 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., Methods: 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., Results: 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., Conclusion: APT imaging may be a useful technique in the diagnosis and predicting the differentiation of SCCC., (Copyright © 2019 Elsevier Inc. All rights reserved.)

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., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: To investigate the hypothesis that the intravoxel incoherent motion (IVIM) diffusion-weighted imaging may depict microcirculation of meniscus and the perfusion changes in meniscal disorder., Materials and Methods: Fifty patients received diffusion-weighted MRI with multiple b-values ranging from 0 to 400 s/mm 2 . The four horns of the menisci were divided into normal, degenerated, and torn groups. IVIM parameters including perfusion fraction (f), pseudo-diffusion coefficient (D*), true diffusion coefficient (D), and the product of f and D* (f D*) of normal meniscal red zone and white zone were derived and compared for microcirculation changes of normal, degenerated, and torn posterior horn of the medial meniscus (PMM). The parameters between red and white zones among the groups were compared. Significant differences were considered when P < 0.05., Results: Mean f and fD* were significantly higher in the red zone than those in the white zone for the normal four meniscal horns (P < 0.05), whereas D* (P = 0.882, 0.011, 0.593, and 0.33) and D (P = 0.186, 0.099, 0.767, and 0.041) did not significantly differ between the two zones. Among the normal, degenerated, and torn PMM, f was observed to be lower in the red zone of torn horns as compared to the normal horns (P = 0.013). D*, fD*, and D did not exhibit statistically significant difference among different groups (P = 0.353, 0.661, and 0.327, respectively)., Conclusion: This hypothesis driven work shows that IVIM imaging is able to depict microcirculation of meniscus and the perfusion changes in meniscal disorder., Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:1090-1096., (© 2016 International Society for Magnetic Resonance in Medicine.)

Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5 s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p = 0.004 and p = 0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p = 0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI., (Copyright © 2015 John Wiley & Sons, Ltd.)

The objectives of this study were to assess the diffusion parameters derived from intravoxel incoherent motion (IVIM) MRI in head and neck squamous cell carcinoma (HNSCC) and to investigate the agreement between different methods of tumor delineation and two numerical methods to extract the perfusion fraction f. Thirty-seven untreated patients with histopathologically confirmed primary HNSCC were included retrospectively in the study. The entire volume of the primary tumor was outlined on diffusion-weighted images using co-registered morphological images as a guide to the tumor location. Apparent diffusion coefficient (ADC) and IVIM diffusion parameters were estimated considering the largest tumor section as well as the entire tumor volume. A bi-exponential fit was implemented to extract f, D (pure diffusion coefficient) and D* (pseudo-diffusion coefficient). A second simplified method, based on an asymptotic extrapolation, was used to determine f. The agreement between ADC and IVIM diffusion parameters derived from the delineation of single and multiple slices, and between the two f estimations, was assessed by Bland-Altman plots. The inter-slice variability of ADC and IVIM diffusion parameters was evaluated. The Kruskal-Wallis test was used to investigate whether the tumor location had a statistically significant influence on the values of the parameters. Comparing the tumor delineation methods, a better accordance was found for ADC and D, with a mean percentage difference of less than 2%. Larger discrepancies were found for f and D*, with mean differences of 4.5% and 5.5%, respectively. When comparing the two f estimation methods, small mean differences were found (<3.5%), suggesting that the two methods may be considered as equivalent for the assessment of f in our patient population. The observed ADC and IVIM diffusion parameters were dependent on the anatomic site of the lesion, carcinoma of the nasopharynx showing more homogeneous and dissimilar estimations than other HNSCCs., (Copyright © 2013 John Wiley & Sons, Ltd.)

BackgroundPrediction 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.Methods38 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 (ADCT1C, ADCT2-FLAIR) and perfusion fraction (fT1C, fT2-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.ResultsHigher ADCT2-FLAIR at baseline [Odds Ratio (OR) = 1.06, 95% CI 1.01-1.15, p = 0.025], lower fT2-FLAIR at fraction 10 (OR = 2.11, 95% CI 1.04-4.27, p = 0.018), and lack of increase in ADCT2-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 ADCT2-FLAIR at baseline, fT2-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 fT2-FLAIR at fraction 10 (HR = 0.72, 95% CI 0.56-0.95, p = 0.018) was associated with longer PFS.ConclusionADCT2-FLAIR at baseline, its lack of increase from baseline to fraction 20, or fT2-FLAIR at fraction 10 significantly predicted early progression. fT2-FLAIR at fraction 10 was associated with PFS.

Purpose: To determine whether intravoxel incoherent motion (IVIM) parameters correlate with liver regeneration and function recovery after partial hepatectomy (PH) in rats with carbon tetrachloride (CCl4)-induced liver fibrosis. Methods: Sixty-two adult Sprague-Dawley rats were divided into the control group and the fibrosis group with CCl4 injection for 8 weeks. At the end of the 8th week, all rats received left lateral lobe liver resection. Within each group, IVIM imaging (n = 10/group) and histologic and biochemical analyses (n = 3/group/time point) were performed pre- and post-PH (on days 1, 2, 3, 5, 7, 14, and 21). Differences in liver IVIM parameters and correlation between IVIM parameters and Ki-67 indices, hepatocyte diameter, alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBil) values were analyzed. Results: Post-PH, liver true diffusion coefficient (D) values decreased and pseudodiffusion coefficient (D*) and perfusion fraction (PF) values increased, then recovered to pre-PH levels gradually in both fibrosis and control rats. PF in fibrosis group were significantly higher than in controls from 3 to 21 days (P < 0.05). In fibrosis rats, both Ki-67 indices and hepatocyte diameters increased, and a strong correlation was found between PF and Ki-67 indices (r = −0.756; P = 0.03), D* and PF values and ALT, AST, and TBil values (r = −0.762 to −0.905; P < 0.05). In control rats, only hepatocyte diameters increased, and all IVIM parameters correlated well with hepatocyte diameters, ALT, AST and TBil values (r = 0.810 to −1.000; P < 0.05). Conclusion: The regeneration pattern in fibrotic liver tissue was different compared with control livers. IVIM parameters can monitor liver regeneration and functional recovery non-invasively after PH. [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: Amide proton transfer-weighted imaging (APTWI) and intravoxel incoherent motion imaging (IVIM) are valuable MRI techniques applied to cancer.Purpose: To compare APTWI and IVIM in the diagnosis of benign and malignant breast lesions and to evaluate the correlations between different parameters (MTRasym [3.5 ppm], D, D*, and f) and prognostic factors for breast cancer.Study Type: Retrospective.Population: In all, 123 breast lesions were studied before treatment, including 58 benign lesions and 65 malignant lesions.Field Strength/sequence: Conventional MRI (T1 WI, T2 WI, and diffusion-weighted imaging [DWI]), APTWI, and IVIM MRI at 3T.Assessment: The magnetization transfer ratio asymmetry at 3.5 ppm (MTRasym [3.5 ppm]), diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) values were compared between the benign and malignant groups and between groups with different expression levels of prognostic factors.Statistical Tests: Individual sample t-test, χ2 test, Spearman correlation, logistic regression, and the Delong test.Results: The D and MTRasym (3.5 ppm) values of the malignant group were lower than those of the benign group; however, D* and f values were higher than those of the benign group (all P < 0.05). The areas under the curve (AUCs) of D, MTRasym (3.5 ppm), D*, and f were 0.809, 0.778, 0.670, and 0.766, respectively; however, only the difference between AUC (D) and AUC (D*) was significant (Z = 2.374, P < 0.05). The D value showed a low correlation with the pathological grade and Ki-67 expression (| r | = 0.294, 0.367); the f value showed a low correlation with estrogen receptor (ER) expression (| r | = 0.382); and the MTRasym (3.5 ppm) value showed a low correlation with pathological grade (| r | = 0.371).Data Conclusion: This analysis revealed that both IVIM and APTWI could be used for the differential diagnosis of benign and malignant breast lesions, and APTWI-derived MTRasym (3.5 ppm), IVIM-derived D, D*, and f values showed correlations with some prognostic factors for breast cancer.Level Of Evidence: 2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:1175-1186. [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]

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]

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]