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Background: Intravoxel incoherent motion (IVIM) MRI has not been widely used and its role in evaluating exertional heat illness (EHI)‐related myocardial involvement remains unknown. Purpose: To investigate the feasibility of strain curve‐derived trigger delay (TD) IVIM‐MRI and its role in assessing myocardial diffusion and microvascular perfusion of EHI patients. Study Type: Prospective. Subjects: A total of 42 male EHI patients (median age: 21 years) and 22 age‐ and sex‐matched healthy controls (HC). Field Strength/Sequence: A 3‐T, diffusion‐weighted spin‐echo echo‐planar‐imaging sequence. Assessment: IVIM‐MRI was acquired by conventional TD method (group A) or strain curve‐based TD method (group B) in random order. IVIM image quality was evaluated on a 3‐point Likert scale (1, nondiagnostic; 2, moderate; 3, good). Technical success was defined as image quality score = 3. IVIM‐MRI‐derived parameters (pseudo diffusion in the capillaries [D*], perfusion fraction [f], and slow apparent diffusion coefficient [D]) were compared between EHI and HC. Statistical Tests: Student's t‐tests, chi‐square tests, one‐way analysis of variance, receiver operating characteristic (ROC) curve analysis, Pearson's correlation coefficient (r). The statistical significance level was set at P < 0.05. Results: IVIM‐MRI image quality score (median [interquartile range]: 3 [2, 3] vs. 2 [1–3]) and technical success rate (61.9%[13/21] vs. 28.6%[6/21]) were significantly improved in group B. EHI patients showed significantly decreased D* (118.1 ± 23.3 × 10−3 mm2/sec vs. 142.7 ± 42.6 × 10−3 mm2/sec) and f values (0.42 ± 0.12 vs. 0.51 ± 0.11) and significantly higher D values (3.0 ± 0.9 × 10−3 mm2/sec vs. 2.5 ± 0.6 × 10−3 mm2/sec) compared to HC. Relative to D and D*, f showed the most robust efficacy for detecting EHI‐related myocardial injury with the highest area under the ROC curve (0.906: 95% confidence interval, 0.799, 0.967) and sensitivity of 88.5% and specificity of 85.6%. Conclusion: The strain curve‐based TD method significantly improved image quality and technical success rate of IVIM‐MRI, and f value may be an effective biomarker to assess myocardial microcirculation abnormalities of EHI patients. Evidence Level: 2. Technical Efficacy: Stage 3. [ABSTRACT FROM AUTHOR]

Background: How the functional interactions of the basal ganglia/thalamus with the cerebral cortex and the cerebellum change over the adult lifespan in movie‐watching and resting‐state is less clear. Purpose: To investigate the functional changes in the organization of the human cortical–subcortical functional networks over the adult lifespan using movie‐watching and resting‐state fMRI data. Study Type: Cohort. Subjects: Healthy 467 adults (cross‐sectional individuals aged 18–88 years) from the Cambridge Centre for Ageing and Neuroscience (www.cam-can.com). Field Strength/Sequence: fMRI using a gradient‐echo echo‐planar imaging (EPI) sequence at 3 T. Assessment: Functional connectivities (FCs) of the subcortical subregions (i.e. the basal ganglia and thalamus) with both the cerebral cortex and cerebellum were examined in fMRI data acquired during resting state and movie‐watching. And, fluid intelligence scores were also assessed. Statistical Tests: Student's t‐tests, false discovery rate (FDR) corrected. Results: As age increased, FCs that mainly within the basal ganglia and thalamus, and between the basal ganglia/thalamus and cortical networks (including the dorsal attention, ventral attention, and limbic networks) were both increased/decreased during movie‐watching and resting states. However, FCs showed a state‐dependent component with advancing age. During the movie‐watching state, the FCs between the basal ganglia/thalamus and cerebellum/frontoparietal control networks were mainly increased with age, and the FCs in the somatomotor network were decreased with age. During the resting state, the FCs between the basal ganglia/thalamus and default mode/visual networks were mainly increased with age, and the FCs in the cerebellum were mainly decreased with age. Moreover, inverse relationships between FCs and fluid intelligence were mainly found in these network regions. Data Conclusion: Our study may suggest that changes in cortical–subcortical functional networks across the adult lifespan were both state‐dependent and stable traits, and that aging fMRI studies should consider the effects of both physiological characteristics and individual situations. Evidence Level: 2. Technical Efficacy: Stage 3. [ABSTRACT FROM AUTHOR]

Background: Renal diffusion‐weighted imaging (DWI) involves microstructure and microcirculation, quantified with diffusion tensor imaging (DTI), intravoxel incoherent motion (IVIM), and hybrid models. A better understanding of their contrast may increase specificity. Purpose: To measure modulation of DWI with cardiac phase and flow‐compensated (FC) diffusion gradient waveforms. Study Type: Prospective. Population: Six healthy volunteers (ages: 22–48 years, five females), water phantom. Field Strength/Sequence: 3‐T, prototype DWI sequence with 2D echo‐planar imaging, and bipolar (BP) or FC gradients. 2D Half‐Fourier Single‐shot Turbo‐spin‐Echo (HASTE). Multiple‐phase 2D spoiled gradient‐echo phase contrast (PC) MRI. Assessment: BP and FC water signal decays were qualitatively compared. Renal arteries and velocities were visualized on PC‐MRI. Systolic (peak velocity), diastolic (end stable velocity), and pre‐systolic (before peak velocity) phases were identified. Following mutual information‐based retrospective self‐registration of DWI within each kidney, and Marchenko‐Pastur Principal Component Analysis (MPPCA) denoising, combined IVIM‐DTI analysis estimated mean diffusivity (MD), fractional anisotropy (FA), and eigenvalues (λi) from tissue diffusivity (Dt), perfusion fraction (fp), and pseudodiffusivity (Dp, Dp,axial, Dp,radial), for each tissue (cortex/medulla, segmented on b0/FA respectively), phase, and waveform (BP, FC). Monte Carlo water diffusion simulations aided data interpretation. Statistical Tests: Mixed model regression probed differences between tissue types and pulse sequences. Univariate general linear model analysis probed variations among cardiac phases. Spearman correlations were measured between diffusion metrics and renal artery velocities. Statistical significance level was set at P < 0.05. Results: Water BP and FC signal decays showed no differences. Significant pulse sequence dependence occurred for λ1, λ3, FA, Dp, fp, Dp,axial, Dp,radial in cortex and medulla, and medullary λ2. Significant cortex/medulla differences occurred with BP for all metrics except MD (systole [P = 0.224]; diastole [P = 0.556]). Significant phase dependence occurred for Dp, Dp,axial, Dp,radial for BP and medullary λ1, λ2, λ3, MD for FC. FA correlated significantly with velocity. Monte Carlo simulations indicated medullary measurements were consistent with a 34 μm tubule diameter. Data Conclusion: Cardiac gating and flow compensation modulate of measurements of renal diffusion. Evidence Level: 2 Technical Efficacy Stage: 2 [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance elastography (MRE) is an imaging technique that can noninvasively assess the shear properties of the intervertebral disc (IVD). Unlike the standard gradient recalled echo (GRE) MRE technique, a spin‐echo echo‐planar imaging (SE‐EPI) sequence has the potential to improve imaging efficiency and patient compliance. Purpose: To validate the use of an SE‐EPI sequence for MRE of the IVD compared against the standard GRE sequence. Study Type: Cross‐over. Subjects: Twenty‐eight healthy volunteers (15 males and 13 females, age range: 19–55). Field Strength/Sequence: 3 T; GRE, SE‐EPI with breath holds (SE‐EPI‐BH) and SE‐EPI with free breathing (SE‐EPI‐FB) MRE sequences. Assessment: MRE‐derived shear stiffnesses were calculated via principal frequency analysis. SE‐EPI derived shear stiffness and octahedral shear strain signal‐to‐noise ratios (OSS‐SNR) were compared against those derived using the GRE sequence. The reproducibility and repeatability of SE‐EPI stiffness measurements were determined. Shear stiffness was evaluated in the nucleus pulposus (NP) and annulus fibrosus (AF) regions of the disc. Scan times between sequences were compared. Statistical Tests: Linear mixed models, Bland–Altman plots, and Lin's concordance correlation coefficients (CCCs) were used with P < 0.05 considered statistically significant. Results: Good correlation was observed between shear stiffnesses derived from the SE‐EPI sequences with those derived from the GRE sequence with CCC values greater than 0.73 and 0.78 for the NP and AF regions, respectively. OSS‐SNR was not significantly different between GRE and SE‐EPI sequences (P > 0.05). SE‐EPI sequences generated highly reproducible and repeatable stiffness measurements with CCC values greater than 0.97 in the NP and AF regions and reduced scan time by at least 51% compared to GRE. SE‐EPI‐BH and SE‐EPI‐FB stiffness measurements were similar with CCC values greater than 0.98 for both regions. Data Conclusion: SE‐EPI‐based MRE‐derived stiffnesses were highly reproducible and repeatable and correlated with current standard GRE MRE‐derived stiffness estimates while reducing scan times. Level of Evidence: 1 Technical Efficacy Stage: 1 [ABSTRACT FROM AUTHOR]

Background: Detecting and measuring intraluminal thrombus has prognostic and therapeutic implications for stroke patients. Purpose: To investigate the feasibility of 3D isotropic high‐resolution T1w‐CUBE imaging to detect and measure intraluminal thrombus in stroke patients. Study Type: Retrospective. Subjects: A total of 93 patients with acute (N = 39) and subacute (N = 54) stroke. Field Strength/Sequence: A 3.0 T/spin‐echo echo‐planar diffusion‐weighted imaging (DWI), high‐resolution T1w‐CUBE imaging and 3D flow compensated gradient‐echo susceptibility‐weighted imaging (SWI). Assessment: Data assessment was performed by three neuroradiologists with 11, 13, and 20 years of clinical experience. The accuracy of T1W‐CUBE and SWI in diagnosing thrombosis was compared by using digital subtraction angiography (DSA) as the reference. For thrombus length measurement, the image quality of proximal and distal thrombus of T1w‐CUBE images was first evaluated with a 4‐point rating system. Then, the proximal and distal positions to lesions were determined on T1w‐CUBE images and compared with those from DSA acquired during endovascular reperfusion therapy. If comparable both locations were found between CUBE and DSA, CUBE imaging can thus be considered for accurate measurement of thrombus length. Statistical Tests: Fleiss' Kappa; the area under the receiver operating characteristic (ROC) curve (AUC); Pearson's chi‐squared test with Yates' continuity correction. Results: Moderate‐to‐good interobserver agreements were validated with all Kappa coefficients higher than 0.40 in thrombus diagnosis and measurement. CUBE imaging showed higher clinical efficacy than SWI (AUC: 0.966 vs. 0.850) in thrombus diagnosis. Additionally, high quality of CUBE imaging was confirmed with 3 or 4 points rated by all three observers. Compared to intraoperative DSA, T1w CUBE showed consistent proximal and distal positions of thrombi in 16 of the 18 patients, validating the accuracy of T1w‐CUBE in measuring thrombus length. Data Conclusion: T1w‐CUBE imaging has potential to facilitate diagnosis and measurement of intraluminal thrombus. Evidence Level: 4 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) denoising through deep learning (DL) often faces insufficient training data from patients. One solution is to train DL models using healthy subjects' data which are more widely available and transfer them to patients' data. Purpose: To evaluate the transferability of a DL‐based ASL MRI denoising method (DLASL). Study Type: Retrospective. Subjects: Four hundred and twenty‐eight subjects (189 females) from three cohorts. Field Strength/Sequence: 3 T two‐dimensional (2D) echo‐planar imaging (EPI)‐based pseudo‐continuous ASL (PCASL) and 2D EPI‐based pulsed ASL (PASL) sequences. Assessment: DLASL was trained using young healthy adults' PCASL data (Dataset 1: 250/30 subjects as training/validation set) and was directly transferred (DTF) to PCASL data from Dataset 2 (45 subjects test set) of normal controls (NC) and Alzheimer's disease (AD) groups. DLASL was fine‐tuned (DLASLFT) and tested on PASL data from Dataset 3 (103 subjects test set) of NC and AD. An existing non‐DL method (NonDL) was used for comparison. Cerebral blood flow (CBF) images from ASL MRI were compared between NC and AD to assess characteristic hypoperfusion (lower CBF) patterns in AD. CBF image quality and CBF map sensitivity for detecting hypoperfusion using peak t‐value and suprathreshold cluster size are outcome measures. Statistical Tests: Paired t‐test, two‐sample t‐test, one‐way analysis of variance, and Tukey honestly significant difference, and linear mixed‐effects models were used. P < 0.05 was considered statistically significant. Results: Mean contrast‐to‐noise ratio (CNR) of Dataset 2 showed that DTF outperformed NonDL (AD: 3.38 vs. 2.64, NC: 3.80 vs. 3.36). On Dataset 3, DLASLFT outperformed NonDL measured by mean CNR (AD: 2.45 vs. 1.87, NC: 2.54 vs. 2.17) and mean radiologic score (2.86 vs. 2.44). Image quality improvement was significant on both test sets. DTF and DLASLFT improved sensitivity for detecting AD‐related hypoperfusion patterns compared with NonDL. Data Conclusion: We demonstrated the DLASL's transferability across different ASL sequences and different populations. Level of Evidence: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: In the medical imaging domain, deep learning-based methods have yet to see widespread clinical adoption, in part due to limited generalization performance across different imaging devices and acquisition protocols. The deviation between estimated brain age and biological age is an established biomarker of brain health and such models may benefit from increased cross-site generalizability. Purpose: To develop and evaluate a deep learning-based image harmonization method to improve cross-site generalizability of deep learning age prediction. Study Type: Retrospective. Population: Eight thousand eight hundred and seventy-six subjects from six sites. Harmonization models were trained using all subjects. Age prediction models were trained using 2739 subjects from a single site and tested using the remaining 6137 subjects from various other sites. Field Strength/Sequence: Brain imaging with magnetization prepared rapid acquisition with gradient echo or spoiled gradient echo sequences at 1.5 T and 3 T. Assessment: StarGAN v2, was used to perform a canonical mapping from diverse datasets to a reference domain to reduce site-based variation while preserving semantic information. Generalization performance of deep learning age prediction was evaluated using harmonized, histogram matched, and unharmonized data. Statistical Tests: Mean absolute error (MAE) and Pearson correlation between estimated age and biological age quantified the performance of the age prediction model. Results: Our results indicated a substantial improvement in age prediction in out-of-sample data, with the overall MAE improving from 15.81 (±0.21) years to 11.86 (±0.11) with histogram matching to 7.21 (±0.22) years with generative adversarial network (GAN)-based harmonization. In the multisite case, across the 5 out-of-sample sites, MAE improved from 9.78 (±6.69) years to 7.74 (±3.03) years with histogram normalization to 5.32 (±4.07) years with GAN-based harmonization. Data Conclusion: While further research is needed, GAN-based medical image harmonization appears to be a promising tool for improving cross-site deep learning generalization. [ABSTRACT FROM AUTHOR]

Background: We have developed hybrid nanoparticles (NPs) by co‐loading copper sulfide (CuS) NPs and glucose oxidase (GOD) (CuS@GOD NPs) to explore their antitumor properties. Purpose To investigate the feasibility of using multiparametric magnetic resonance imaging (MRI) including intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and R2* mapping to quantitatively assess the early antitumor effect of CuS@GOD NPs. Study type: Prospective. Animal model: The orthotopic BALB/c mice 4 T1 breast cancer model. The 4 T1 xenografts in group 1 mice received normal saline, group 2 received CuS@GOD NPs, group 3 received CuS NPs plus laser, and group 4 received CuS@GOD NPs plus laser (n = 28 for each group). Field Strength/Sequence: A 3.0 T/IVIM‐DWI MRI single‐shot echo‐planar imaging, R2* mapping spoiled gradient recalled echo (SPGR) sequence, T2‐weighted images (T2WI) and T1‐weighted images (T1WI) fast spin echo (FSE) sequence. Assessment The IVIM‐DWI and R2* mapping were performed before and after treatment at 0 hour, 0.5 hour, 1 hour, 2 hours, 4 hours, and 24 hours in four groups and the MRI parameters were obtained. Correlation analysis between the MRI parameters and histological analyses was conducted. Statistical Tests: One‐way ANOVA, Pearson's correlation analysis, two independent samples t test, intraclass correlation coefficient. P < 0.05 was considered to be statistically significant. Results: In group 4, the tumoral D value was significantly higher than that of group 2 at 24 hours (0.541 ± 0.065 vs. 0.492 ± 0.051). The f value of group 4 was significantly lower than that of groups 1 and 2 at 2 hours (10.83 ± 2.16 vs. 14.28 ± 1.86, 16.67 ± 3.53, respectively). The R2* value was significantly increased at 0 hour in group 4 compared to that of groups 1 and 2 (64.552 ± 4.663 vs. 42.441 ± 1.516, 43.165 ± 1.709, respectively). D, f, and R2* were correlated with the histological staining results (r = 0.695–0.970). Data Conclusion: The IVIM‐DWI‐derived D and f and R2* mapping‐derived R2* could monitor early response to CuS@GOD NPs treatment in vivo. Evidence Level 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Single‐shot diffusion‐weighted imaging (ssDWI) has been shown useful for detecting active bowel inflammation in Crohn's disease (CD) without MRI contrast. However, ssDWI suffers from geometric distortion and low spatial resolution. Purpose To compare conventional ssDWI with higher‐resolution ssDWI (HR‐ssDWI) and multi‐shot DWI based on multiplexed sensitivity encoding (MUSE‐DWI) for evaluating bowel inflammation in CD, using contrast‐enhanced MR imaging (CE‐MRI) as the reference standard. Study Type: Prospective. Subjects: Eighty nine patients with histological diagnosis of CD from previous endoscopy (55 male/34 female, age: 17–69 years). Field Strength/Sequences: ssDWI (2.7 mm × 2.7 mm), HR‐ssDWI (1.8 mm × 1.8 mm), MUSE‐DWI (1.8 mm × 1.8 mm) based on echo‐planar imaging, T2‐weighted imaging, and CE‐MRI sequences, all at 1.5 T. Assessment Five raters independently evaluated the tissue texture conspicuity, geometry accuracy, minimization of artifacts, diagnostic confidence, and overall image quality using 5‐point Likert scales. The diagnostic performance (sensitivity, specificity and accuracy) of each DWI sequences was assessed on per‐bowel‐segment basis. Statistical Tests: Inter‐rater agreement for qualitative evaluation of each parameter was measured by the intra‐class correlation coefficient (ICC). Paired Wilcoxon signed‐rank tests were performed to evaluate the statistical significance of differences in qualitative scoring between DWI sequences. A P value <0.05 was considered to be statistically significant. Results: Tissue texture conspicuity, geometric distortions, and overall image quality were significantly better for MUSE‐DWI than for ssDWI and HR‐ssDWI with good agreement among five raters (ICC: 0.70–0.89). HR‐ssDWI showed significantly poorer performance to ssDWI and MUSE‐DWI for all qualitative scores and had the worst diagnostic performance (sensitivity of 57.0% and accuracy of 87.3%, with 36 undiagnosable cases due to severe artifacts). MUSE‐DWI showed significantly higher sensitivity (97.5% vs. 86.1%) and accuracy (98.9% vs. 95.1%) than ssDWI for detecting bowel inflammation. Data Conclusion: MUSE‐DWI was advantageous in assessing bowel inflammation in CD, resulting in improved spatial resolution and image quality. Level of Evidence: 2 Technical Efficacy Stage: 2 [ABSTRACT FROM AUTHOR]

Background: The diseased‐related dynamic functional network connectivity (dFNC) disruption and its relationship with cognitive impairment in hepatitis B virus‐related cirrhosis (HBV‐RC) patients with minimal hepatic encephalopathy (MHE) and no MHE (NMHE) remain unknown. This knowledge would help identify MHE pathophysiology and monitor disease progression in HBV‐RC patients. Purpose: To investigate the dFNC in patients with NMHE and MHE and the relationship between dFNC indices with the psychometric hepatic encephalopathy score (PHES). Study type: Prospective. Population: Thirty HBV‐RC patients (including 17 NMHE and 13 MHE) and 38 healthy controls (HC). Field strength/sequence: A 1.5 T MRI and gradient‐echo echo‐planar imaging and fast field echo three‐dimensional T1‐weighted imaging. Assessment: The independent components, dFNC matrix and dFNC indices (mean dwell times [DT], number of states, number of transitions, and fraction time in each state), were obtained through GIFT package. Cognitive measurement and patients grouping were based on PHES tests. Statistical Tests: One‐way ANOVA, chi‐square test, two‐sample t‐test, Kruskal–Wallis test, spearman's correlation analysis and the false discovery rate. Significance level: P < 0.05. Results: Compared to HC (21.1 ± 4.02), the DT of state 1 decreased in NMHE (9.0 ± 3.04, P = 0.062, 95% confidence interval [CI] is −0.65 to 24.88) and significantly in MHE stage (1.2 ± 1.01) and was significantly correlated with PHES (r = 0.5) for all patients. The DT of state 2 increased gradually in NMHE (75.2 ± 13.10, P = 0.052, 95% CI, −54.23 to 0.28) and significantly in MHE stage (94.6 ± 15.61) when compared to HC (48.2 ± 6.97). Moreover, the connectivity between cognitive control network (CCN) and visual network (VIS) in state 1 (0.7 ± 0.79) and between default mode (DMN) and VIS in state 2 (−0.2 ± 0.29) decreased significantly in MHE when compared to HC (0.1 ± 0.68 for CCN‐VIS in state 1 and 0.1 ± 0.17 for DMN‐VIS for state 2). Data Conclusion: dFNC exhibited progressive impairment as the disease advances in patients with HBV‐RC. Evidence Level: 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Accurate evaluation of the invasion depth of tumors with a Vesical Imaging-Reporting and Data System (VI-RADS) score of 3 is difficult.Purpose: To evaluate the diagnostic performance of a new magnetic resonance imaging (MRI) strategy based on the integration of the VI-RADS and tumor contact length (TCL) for the diagnosis of muscle-invasive bladder cancer (MIBC).Study Type: Single center, retrospective.Subjects: A group of 179 patients with a mean age of 67 years (range, 24.0-96.0) underwent multiparametric MRI (mpMRI) before surgery, including 147 (82.1%) males and 32 (17.9%) females. Twenty-four (13.4%), 90 (50.3%), 43 (24.0%), 15 (8.4%), and 7 (3.9%) cases were Ta, T1, T2, T3, and T4, respectively.Field Strength/sequence: A 1.5 T and 3.0 T, T2-weighted turbo spin-echo (TSE), single-shot echo-planar (SS-EPI), diffusion-weighted imaging (DWI), and T1-weighted volumetric interpolated breath-hold examination (T1-VIBE).Assessment: Three radiologists independently graded the VI-RADS score and measured the TCL on index lesion images. A proposed MRI strategy called VI-RADS_TCL was introduced by modifying the VI-RADS score, which was downgraded to VI-RADS 3F (equal to a VI-RADS score of 2) if VI-RADS = 3 and TCL < 3 cm.Statistical Tests: Intraclass correlation coefficients (ICCs), Mann-Whitney U test, chi-square tests, receiver operating characteristic (ROC) curves, and 2 × 2 contingency tables were applied.Results: Inter-reader agreement values were 0.941 (95% CI, 0.924-0.955) and 0.934 (95% CI, 0.916-0.948) for the TCL and VI-RADS score. The TCL was significantly increased in the MIBC group (6.40-6.85 cm) compared with the NMIBC group (1.98-2.45 cm) (P < 0.05). The specificity and positive predictive values (PPV) of VI-RADS_TCL were 82.46%-87.72% and 90.91%-91.59%, which were significantly greater than VI-RADS score (P < 0.05). Additionally, 52.17%-55.88% NMIBC lesions with VI-RADS 3 were downgraded to 3F by using VI-RADS_TCL.Data Conclusion: The proposed MRI strategy could reduce the false-positive rate of lesions with a VI-RADS score of 3 while retaining sensitivity.Evidence Level: 4 TECHNICAL EFFICACY: 2. [ABSTRACT FROM AUTHOR]

BACKGROUND: Whole‐body diffusion‐weighted MRI (WB‐DWI) is useful for assessing disease activity in castration‐resistant prostate cancer (CRPC). MET‐RADS‐P is a subjective assessment‐based reporting system proposed to standardize the interpretation of WB‐DWI. However, a quantitative evaluation of WB‐DWI has not been fully investigated. PURPOSE: To investigate the validity, and analyze the prognostic value, of quantitative evaluation of WB‐DWI based on apparent diffusion coefficient (ADC) values for CRPC. STUDY TYPE: Retrospective. POPULATION: Sixty‐six patients with CRPC. The median age was 75 years. During the median follow‐up period of 25.2 months, 23 of 66 patients (34.8%) died of prostate cancer. FIELD STRENGTH/SEQUENCE: A 1.5 T WB‐DWI was used with two b‐values (0 s/mm2–1000 s/mm2). A single‐shot echo‐planar imaging sequence was used. ASSESSMENT: WB‐DWI were evaluated by three readers according to MET‐RADS‐P scoring system. Using imaging software, Attractive BDScore, tumor diffusion volume (mDV) and ADC value of metastatic lesion (mADC) was calculated by two readers. The mDV was calculated with ADC values (×10−3 mm2/sec) of 0.4–0.9 (mDV0.4–0.9), 0.9–1.4 (mDV0.9–1.4), and 1.4–1.8 (mDV1.4–1.8), respectively. STATISTICAL TESTS: Spearman's rank correlation coefficient was used to assess the correlation. The relationships between the variables with cancer‐specific survival (CSS) were evaluated. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: mDVs showed a strong positive correlation with MET‐RADS‐P scores (r = 0.90/0.87, P < 0.05 for both). mDV showed a statistically significant association with CSS (hazard ratio [HR]: 1.01, P < 0.05). When the mDVs calculated based on the ADC values were included, mDV0.4–0.9 (HR: 1.02, P < 0.05) and the number of therapeutic lines (HR: 1.35, P < 0.05) were significant independent indicators of CSS shortening. CONCLUSION: Assessment of metastatic tumor volume based on ADC values can be used in the prognostic evaluation of patients with CRPC. WB‐DWI might be a potential prognostic imaging biomarker for CRPC. Evidence Level: 4 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Diffusion-weighted imaging (DWI) is often included in breast MRI protocols. Although breast diffusion imaging has been part of many of our clinical protocols for years, its usability has been unfortunately limited due to artifacts, distortions, and unreliable data due to the challenging geometry of the breast. Readout-segmented Echo-planar diffusion-weighted MR imaging improves the differentiation of breast cancer receptor statuses compared with conventional diffusion-weighted imaging. [Extracted from the article]

Background: A reduction in scan time of 4D Flow MRI would facilitate clinical application. A recent study indicates that echo-planar imaging (EPI) 4D Flow MRI allows for a reduction in scan time and better data quality than the recommended k-space segmented spoiled gradient echo (SGRE) sequence. It was argued that the poor data quality of SGRE was related to the nonrecommended absence of respiratory motion compensation. However, data quality can also be affected by the background offset compensation.Purpose: To compare the data quality of respiratory motion-compensated SGRE and EPI 4D Flow MRI and their dependence on background correction (BC) order.Study Type: Retrospective.Subjects: Eighteen healthy subjects (eight female, mean age 32 ± 5 years).Field Strength and Sequence: 1.5 T. [Correction added on July 26, 2019, after first online publication: The preceding field strength was corrected.] SGRE and EPI-based 4D Flow MRI.Assessment: Data quality was investigated visually and by comparing flows through the cardiac valves and aorta. Measurements were obtained from transvalvular flow and pathline analysis.Statistical Tests: Linear regression and Bland-Altman analysis were used. Wilcoxon test was used for comparison of visual scoring. Student's t-test was used for comparison of flow volumes.Results: No significant difference was found by visual inspection (P = 0.08). Left ventricular (LV) flows were strongly and very strongly associated with SGRE and EPI, respectively (R2 = 0.86-0.94 SGRE; 0.71-0.79 EPI, BC0-4). LV and right ventricular (RV) outflows and LV pathline flows were very strongly associated (R2 = 0.93-0.95 SGRE; 0.88-0.91 EPI, R2 = 0.91-0.95 SGRE; 0.91-0.93 EPI, BC1-4). EPI LV outflow was lower than the short-axis-based stroke volume. EPI RV outflow and proximal descending aortic flow were lower than SGREs.Data Conclusion: Both sequences yielded good internal data consistency when an adequate background correction was applied. Second and first BC order were considered sufficient for transvalvular flow analysis in SGRE and EPI, respectively. Higher BC orders were preferred for particle tracing. Level of Evidence 4 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2020;51:885-896. [ABSTRACT FROM AUTHOR]