The clinical value of combining shear wave elastography, VOCAL technique, and T2* MRI of early gestation placenta to predict pre-eclampsia.

OBJECTIVE: To investigate the clinical value of combining shear wave elastography (SWE) with the Volumetric Organ Computer-Aided AnaLysis (VOCAL) technique and T2* magnetic resonance imaging (MRI) to predict pre-eclampsia (PE). METHODS: From December 2022 to March 2023, we recruited 31 pregnant women diagnosed with PE at our hospital as the observation group and 85 normal pregnant women as the control group. Differences in placental elasticity, vascularization index (VI), flow index (FI), vascularization flow index (VFI), and T2* MRI perfusion fraction (f) were compared between the two groups. Received operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of placental elasticity, VI, FI, VFI, f, and their combination for predicting PE. RESULTS: Placental elasticity was higher in the observation group than in the control group, while VI, FI, VFI, and f were lower in the observation group (all p < 0.05). The area under the curve (AUC) for placental elasticity, VI, FI, VFI, f, and their combination for predicting PE were 0.85, 0.77, 0.78, 0.84, 0.65, and 0.94, respectively. The sensitivity was 71%, 55%, 94%, 65%, 55%, and 81%. The specificity was 92%, 91%, 60%, 92%, 79%, and 98%. The combined prediction model had a higher AUC than the individual predictors (p < 0.05). CONCLUSION: SWE combined with VOCAL technique and T2* MRI has high value for predicting PE and can provide reference information for clinical diagnosis.

Towards detection of early response in neoadjuvant chemotherapy of breast cancer using Bayesian intravoxel incoherent motion.

Introduction: The early identification of good responders to neoadjuvant chemotherapy (NACT) holds a significant potential in the optimal treatment of breast cancer. A recent Bayesian approach has been postulated to improve the accuracy of the intravoxel incoherent motion (IVIM) model for clinical translation. This study examined the prediction and early sensitivity of Bayesian IVIM to NACT response. Materials and methods: Seventeen female patients with breast cancer were scanned at baseline and 16 patients were scanned after Cycle 1. Tissue diffusion and perfusion from Bayesian IVIM were calculated at baseline with percentage change at Cycle 1 computed with reference to baseline. Cellular proliferative activity marker Ki-67 was obtained semi-quantitatively with percentage change at excision computed with reference to core biopsy. Results: The perfusion fraction showed a significant difference (p = 0.042) in percentage change between responder groups at Cycle 1, with a decrease in good responders [-7.98% (-19.47-1.73), n = 7] and an increase in poor responders [10.04% (5.09-28.93), n = 9]. There was a significant correlation between percentage change in perfusion fraction and percentage change in Ki-67 (p = 0.042). Tissue diffusion and pseudodiffusion showed no significant difference in percentage change between groups at Cycle 1, nor was there a significant correlation against percentage change in Ki-67. Perfusion fraction, tissue diffusion, and pseudodiffusion showed no significant difference between groups at baseline, nor was there a significant correlation against Ki-67 from core biopsy. Conclusion: The alteration in tumour perfusion fraction from the Bayesian IVIM model, in association with cellular proliferation, showed early sensitivity to good responders in NACT. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT03501394, identifier NCT03501394.

Clinical implications of Peri-hematomal edema microperfusion fraction in intracerebral hemorrhage intravoxel incoherent motion imaging - A pilot study.

BACKGROUND AND PURPOSE: Perihematomal edema (PHE) represents the secondary brain injury after intracerebral hemorrhage (ICH). However, neurobiological characteristics of post-ICH parenchymal injury other than PHE volume have not been fully characterized. Using intravoxel incoherent motion imaging (IVIM), we explored the clinical correlates of PHE diffusion and (micro)perfusion metrics in subacute ICH. MATERIALS AND METHODS: In 41 consecutive patients scanned 1-to-7 days after supratentorial ICH, we determined the mean diffusion (D), pseudo-diffusion (D*), and perfusion fraction (F) within manually segmented PHE. Using univariable and multivariable statistics, we evaluated the relationship of these IVIM metrics with 3-month outcome based on the modified Rankin Scale (mRS). RESULTS: In our cohort, the average (± standard deviation) age of patients was 68.6±15.6 years, median (interquartile) baseline National Institute of Health Stroke Scale (NIHSS) was 7 (3-13), 11 (27 %) patients had poor outcomes (mRS>3), and 4 (10 %) deceased during the follow-up period. In univariable analyses, admission NIHSS (p < 0.001), ICH volume (p = 0.019), ICH+PHE volume (p = 0.016), and average F of the PHE (p = 0.005) had significant correlation with 3-month mRS. In multivariable model, the admission NIHSS (p = 0.006) and average F perfusion fraction of the PHE (p = 0.003) were predictors of 3-month mRS. CONCLUSION: The IVIM perfusion fraction (F) maps represent the blood flow within microvasculature. Our pilot study shows that higher PHE microperfusion in subacute ICH is associated with worse outcomes. Once validated in larger cohorts, IVIM metrics may provide insight into neurobiology of post-ICH secondary brain injury and identify at-risk patients who may benefit from neuroprotective therapy.

Prediction of short-term treatment outcome of nasopharyngeal carcinoma based on voxel incoherent motion imaging and arterial spin labeling quantitative parameters.

Purpose: To evaluate the early response of chemoradiotherapy (CRT) in nasopharyngeal carcinoma (NPC) based on intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and three-dimensional pseudo-continuous arterial spin labeling (3D pCASL). Materials and methods: Forty patients diagnosed with NPC were recruited and divided into complete remission (CR) and partial remission (PR) group after CRT. All patients underwent IVIM and ASL and the related parameters was obtained. These parameters include pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), average blood flow ( BFavg), minimum blood flow (BFmin), and maximum blood flow (BFmax). Student's t test was used to compare the difference in ASL and IVIM derived parameters between CR and PR. The Areas under curve (AUC) of the receiver operating characteristic (ROC) was used to analyze the diagnostic performance of each parameter of ASL and IVIM to the treatment outcome. Results: the D value of IVIM in CR group was lower than that of the PR group ( P = 0.014),. Among the parameters of ASL, the BFavg and BFmax of the CR group were higher than those of the PR group(p = 0.004,0.013), but the BFmin had no statistical significance in the two groups（P = 0.54）. AUC of D, BFavg, and BFmax is about 0.731, 0.753, and 0.724, respectively, all of their combined AUC diagnosis was 0.812. Conclusion: The early response of NPC after CRT can predict by IVIM's diffusion parameters and ASL-related blood flow parameters.

Perfusion fraction derived from IVIM analysis of diffusion-weighted MRI in the assessment of placental vascular malperfusion antenatally.

INTRODUCTION: Specific placental pathologies that may impact fetal development, such as vascular malperfusion, are diagnosed postpartum. We aimed to evaluate if placental perfusion fraction (f) derived from intravoxel incoherent motion (IVIM) analysis of diffusion-weighted magnetic resonance imaging (DWI) can be used to identify specific types of placental vascular malperfusion antenatally. METHOD: 93 women who underwent placental DWI with multiple b-values at 23.9-41.3 week's gestation and postpartum histological examination were identified in the local placental MRI research database. Based on the placental examination, 44 were defined as normal controls and 49 cases had placental vascular malperfusion. Vascular malperfusion was subdivided into fetal vascular malperfusion (n = 13), maternal vascular malperfusion (n = 30) or both (n = 6). For each placenta, regions of interest were drawn on three placental slices and their mean f was estimated using intravoxel incoherence motion analysis. RESULTS: In normal placentas mean f was 26.0 ± 4.6% (mean ± SD) and no linear correlation between f and gestational age was found, r = -0.05, p = 0.72. Placentas with fetal vascular malperfusion showed a significantly lower f (22.7 ± 4.4%) compared to normal controls, p = 0.03. In cases of maternal vascular malperfusion (25.2 ± 6.4%), no significant difference in f was revealed, p = 0.55. CONCLUSIONS: These results indicate that placental DWI-derived f may identify fetal vascular malperfusion in vivo. This study confirms a previous pilot study and provides initial evidence that fetal and maternal vascular malperfusion have different MRI signatures. Future studies are needed to further explore the clinical significance of this interesting finding.

Assessment of Impaired Cerebrovascular Reactivity in Chronic Cerebral Ischemia using Intravoxel Incoherent Motion Magnetic Resonance Imaging.

BACKGROUND: The severity of chronic cerebral ischemia can be assessed using cerebrovascular reactivity (CVR) to acetazolamide (ACZ) challenge, which is measured by single-photon emission computed tomography (SPECT); however, this is an invasive method. We investigated whether intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) can assess impaired CVR in preoperative patients with chronic cerebral ischemia and compared it to SPECT-CVR. METHODS: Forty-seven patients with unilateral cervical carotid artery stenosis underwent diffusion-weighted MRI with 11 b-values in the range of 0-800 s/mm2 and cerebral perfusion SPECT with the ACZ challenge. The perfusion fraction (f) and diffusion coefficient (D) of the IVIM parameters were calculated using a bi-exponential model. The f and D values and these ratios of the ipsilateral middle cerebral artery territory against the contralateral side were compared with the CVR values of the affected side calculated from the SPECT data. RESULTS: The IVIM-f and D values in the affected side were significantly higher than those in the unaffected side (median: 7.74% vs. 7.45%, p = 0.027; 0.816 vs. 0.801 10-3mm2/s, p < 0.001; respectively). However, there were no significant correlations between the f or D values and SPECT-CVR values in the affected side. In contrast, the f ratio showed a moderate negative correlation with the SPECT-CVR values (r = -0.40, p = 0.006) and detected impaired CVR (< 18.4%) with a sensitivity/specificity of 0.71/0.90. CONCLUSION: The IVIM perfusion parameter, f, can noninvasively assess impaired CVR with high sensitivity and specificity in patients with unilateral cervical carotid artery stenosis.

IVIM Parameters on MRI Could Predict ISUP Risk Groups of Prostate Cancers on Radical Prostatectomy.

PURPOSE: To elucidate the usefulness of intravoxel incoherent motion (IVIM)/apparent diffusion coefficient (ADC) parameters in preoperative risk stratification using International Society of Urological Pathology (ISUP) grades. MATERIALS AND METHODS: Forty-five prostate cancer (PCa) patients undergoing radical prostatectomy (RP) after prostate multiparametric magnetic resonance imaging (mpMRI) were included. The ISUP grades were categorized into low-risk (I-II) and high-risk (III-V) groups, and the concordance between the preoperative and postoperative grades was analyzed. The largest region of interest (ROI) of the dominant tumor on each IVIM/ADC image was delineated to obtain its histogram values (i.e., minimum, mean, and kurtosis) of diffusivity (D), pseudodiffusivity (D*), perfusion fraction (PF), and ADC. Multivariable logistic regression analysis of the IVIM/ADC parameters without and with preoperative ISUP grades were performed to identify predictors for the postoperative high-risk group. RESULTS: Thirty-two (71.1%) of 45 patients had concordant preoperative and postoperative ISUP grades. Dmean, D*kurtosis, PFkurtosis, ADCmin, and ADCmean were significantly associated with the postoperative ISUP risk group (all p < 0.05). Dmean and D*kurtosis (model I, both p < 0.05) could predict the postoperative ISUP high-risk group with an area under the curve (AUC) of 0.842 and a 95% confidence interval (CI) of 0.726-0.958. The addition of D*kurtosis to the preoperative ISUP grade (model II) may enhance prediction performance, with an AUC of 0.907 (95% CI 0.822-0.992). CONCLUSIONS: The postoperative ISUP risk group could be predicted by Dmean and D*kurtosis from mpMRI, especially D*kurtosis. Obtaining the biexponential IVIM parameters is important for better risk stratification for PCa.

ADC, D, f dataset calculated through the simplified IVIM model, with MGMT promoter methylation, age, and ECOG, in 38 patients with wildtype IDH glioblastoma.

Patients undergoing standard chemoradiation post-resection had MRIs at radiation planning and fractions 10 and 20 of chemoradiation. MRIs were 1.5T and 3D T2-FLAIR, pre- and post-contrast 3D T1-weighted (T1) and echo planar DWI with three b-values (0, 500, and 1000s/mm2) were acquired. T2-FLAIR was coregistered to T1C images. Non-overlapping T1 contrast-enhancing (T1C) and nonenhancing T2-FLAIR hyperintense regions were segmented, with necrotic/cystic regions, the surgical cavity, and large vessels excluded. The simplified IVIM model was used to calculate voxelwise diffusion coefficient (D) and perfusion fraction (f) maps; ADC was calculated using the natural logarithm of b = 1000 over b = 0 images. T1C and T2-FLAIR segmentations were brought into this space, and medians calculated. MGMT promoter methylation status (MGMTPMS), age at diagnosis, and Eastern Cooperative Oncology Group (ECOG) performance status were extracted from electronic medical records. The data were presented, analyzed, and described in the article, "Intravoxel incoherent motion (IVIM) modeling of diffusion MRI during chemoradiation predicts therapeutic response in IDH wildtype Glioblastoma", published in Radiotherapy and Oncology [1].

Magnet-targeted delivery of bone marrow-derived mesenchymal stem cells improves therapeutic efficacy following hypoxic-ischemic brain injury.

Stem cell transplantation may represent a feasible therapeutic option for the recovery of neurological function in children with hypoxic-ischemic brain injury; however, the therapeutic efficacy of bone marrow-derived mesenchymal stem cells largely depends on the number of cells that are successfully transferred to the target. Magnet-targeted drug delivery systems can use a specific magnetic field to attract the drug to the target site, increasing the drug concentration. In this study, we found that the double-labeling using superparamagnetic iron oxide nanoparticle and poly-L-lysine (SPIO-PLL) of bone marrow-derived mesenchymal stem cells had no effect on cell survival but decreased cell proliferation 48 hours after labeling. Rat models of hypoxic-ischemic brain injury were established by ligating the left common carotid artery. One day after modeling, intraventricular and caudal vein injections of 1 × 105 SPIO-PLL-labeled bone marrow-derived mesenchymal stem cells were performed. Twenty-four hours after the intraventricular injection, magnets were fixed to the left side of the rats' heads for 2 hours. Intravoxel incoherent motion magnetic resonance imaging revealed that the perfusion fraction and the diffusion coefficient of rat brain tissue were significantly increased in rats treated with SPIO-PLL-labeled cells through intraventricular injection combined with magnetic guidance, compared with those treated with SPIO-PLL-labeled cells through intraventricular or tail vein injections without magnetic guidance. Hematoxylin-eosin and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining revealed that in rats treated with SPIO-PLL-labeled cells through intraventricular injection under magnetic guidance, cerebral edema was alleviated, and apoptosis was decreased. These findings suggest that targeted magnetic guidance can be used to improve the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for hypoxic-ischemic brain injury. This study was approved by the Animal Care and Use Committee of The Second Hospital of Dalian Medical University, China (approval No. 2016-060) on March 2, 2016.

Diagnostic Utility of the Simplified Perfusion Fraction for Identifying Myocardial Injury in Patients With Reperfused ST-segment Elevation Myocardial Infarction.

BACKGROUND: Acute myocardial infarction (AMI) is a disease with high morbidity and mortality worldwide and the evaluation of myocardial injury and perfusion status following myocardial ischemia and reperfusion is of clinical value. PURPOSE: To assess the diagnostic utility of simplified perfusion fraction (SPF) in differentiating salvage and infarcted myocardium and its predictive value for left ventricular remodeling in patients with reperfusion ST-segment elevation myocardial infarction (STEMI). STUDY TYPE: Prospective. POPULATION: Forty-one reperfused STEMI patients and 20 healthy volunteers. FIELD STRENGTH/SEQUENCE: 3.0T MRI. The MR examination included cine, T2 -short tau inversion recovery (T2 -STIR), first pass perfusiong (FPP)，phase sensitive inversion recovery (PSIR), and diffusion-weighted imaging (DWI). ASSESSMENT: SPF values among different myocardium regions (infarcted, salvaged, remote, and MVO) and stages of reperfused STEMI patients as well as normal controls were measured. The diagnostic utility of SPF values in differentiating salvaged and infarcted myocardium was assessed. STATISTICAL ANALYSIS: Independent t-test and the Mann-Whitney U-test. Logistic regression. RESULTS: SPF values in healthy controls were not significantly different than SPF values in the remote myocardium of patients (40.09 ± 1.47% vs. 40.28 ± 1.93%, P = 0.698). In reperfusion STEMI patients, SPF values were lower in infarcted myocardium compared to remote and salvaged myocardium (32.15 ± 2.36% vs. 40.28 ± 1.93%, P < 0.001; 32.15 ± 2.36% vs. 36.68 ± 2.71%, P < 0.001). SPF values of infarcted myocardium showed a rebound increase from acute to convalescent stages (32.15 ± 2.36% vs. 34.69 ± 3.69%, P < 0.001). When differentiating infarcted and salvaged myocardium, SPF values demonstrated an area under the curve (AUC) of 0.89 (sensitivity 85.4%, specificity 80.5%, cutoff 34.42%). Lower SPF values were associated with lower odds ratio (OR = 0.304) of left ventricular remodeling after adjusting for potential confounders with a confidence interval (CI) of 0.129-0.717, P = 0.007. DATA CONCLUSION: SPF might be able to differentiate salvaged and infarcted myocardium and is a strong predictor of left ventricular remodeling in reperfused STEMI patients. Level of Evidence 2 Technical Efficacy Stage 2.

Placental diffusion-weighted MRI in normal pregnancies and those complicated by placental dysfunction due to vascular malperfusion.

INTRODUCTION: Our aim was to assess placental function by diffusion-weighted magnetic resonance imaging (MRI) using intravoxel incoherent motion (IVIM) analysis in uncomplicated pregnancies and pregnancies complicated by placental dysfunction. METHODS: 31 normal pregnancies and 9 pregnancies complicated by placental dysfunction (birthweight ≤ -2SD and histological signs of placental vascular malperfusion) were retrieved from our placental MRI research database. MRI was performed at gestational weeks 20.1-40.6 in a 1.5 T system using 10 b-values (0-1000 s/mm2). Regions of interest were drawn covering the entire placenta in five transverse slices. Diffusion coefficient (D), pseudodiffusion coefficient (D*) and perfusion fraction (f) were estimated by IVIM analysis. RESULTS: In normal pregnancies, placental f decreased linearly with gestational age (r = -0.522, p = 0.002) being 26.2% at week 20 and 18.8% at week 40. D and D* were 1.57 ± 0.03 and 31.7 ± 3.1 mm2/s (mean ± SD), respectively, and they were not correlated with gestational age. In complicated pregnancies, f was significantly reduced (mean Z-score = -1.16; p = 0.02) when compared to the group of normal pregnancies, whereas D and D* did not differ significantly between groups. Subgroup analysis demonstrated that f was predominantly reduced in dysfunctional placentas characterized by fetal vascular malperfusion (mean Z-score = -2.11, p < 0.001) rather than maternal vascular malperfusion (mean Z-score = -0.40, p = 0.42). In addition, f was negatively correlated with uterine artery pulsatility index (r = -0.396, p = 0.01). DISCUSSION: Among parameters obtained by the IVIM analysis, only f revealed significant differences between the normal and the dysfunctional placentas. Subgroup analysis suggests that placental f may be able to discriminate non-invasively between different histological types of vascular malperfusion.

Intravoxel incoherent motion parameters in the evaluation of chronic hepatitis B virus-induced hepatic injury: fibrosis and capillarity changes.

OBJECTIVE: To evaluate the diagnostic efficacy of intravoxel incoherent motion (IVIM) parameters in hepatitis B virus (HBV)-induced hepatic fibrosis using different calculation methods and to investigate histopathologic origins. MATERIALS AND METHODS: Liver biopsies from 37 prospectively recruited chronic hepatitis B patients were obtained. Twelve b-value (0-1000 s/mm2) diffusion-weighted imaging (DWI) was performed with a 1.5 T scanner and was followed by blinded percutaneous liver biopsy. All biopsy specimens were evaluated with Ishak staging, and the microvascular density (MVD) was calculated. Patients were classified as having no/mild (F0-1), moderate (F2-3), or marked (F4-5) fibrosis. Pseudodiffusion (D*), the perfusion fraction (f), and the apparent diffusion coefficient (ADC) were calculated using all b-values, while true diffusion (D) was calculated using all b-values [D0-1000] and b-values greater than 200 s/mm2 [D200-1000]. Three concentric regions of interest (ROIs) (5, 10, and 20 mm) centered on the biopsy site were used. RESULTS: D* was correlated with the MVD (p = 0.015, Pearson's r = 0.415), but f was not (p = 0.119). D0-1000 was inversely correlated with Ishak stage (p = 0.000, Spearman's rs = - 0.685) and was significantly decreased in all the fibrosis groups; however, only the no/mild and marked fibrosis groups had significantly different D200-1000 values. A pairwise comparison of receiver operating characteristic (ROC) curves of D0-1000 and D200-1000 showed significant differences (p = 0.039). D* was the best at discriminating early fibrosis (AUC = 0.861), while the ADC best discriminated advanced fibrosis (AUC = 0.964). CONCLUSION: D* was correlated with the MVD and is a powerful parameter to discriminate early hepatic fibrosis. D significantly decreased with advanced fibrosis stage when using b-values less than 200 s/mm2 in calculations.

Estimation of diffusion, perfusion and fractional volumes using a multi-compartment relaxation-compensated intravoxel incoherent motion (IVIM) signal model.

Compartmental diffusion MRI models that account for intravoxel incoherent motion (IVIM) of blood perfusion allow for estimation of the fractional volume of the microvascular compartment. Conventional IVIM models are known to be biased by not accounting for partial volume effects caused by free water and cerebrospinal fluid (CSF), or for tissue-dependent relaxation effects. In this work, a three-compartment model (tissue, free water and blood) that includes relaxation terms is introduced. To estimate the model parameters, in vivo human data were collected with multiple echo times (TE), inversion times (TI) and b-values, which allowed a direct relaxation estimate alongside estimation of perfusion, diffusion and fractional volume parameters. Compared to conventional two-compartment models (with and without relaxation compensation), the three-compartment model showed less effects of CSF contamination. The proposed model yielded significantly different volume fractions of blood and tissue compared to the non-relaxation-compensated model, as well as to the conventional two-compartment model, suggesting that previously reported parameter ranges, using models that do not account for relaxation, should be reconsidered.

Diagnostic value of hepatic artery perfusion fraction combined with TGF-ß in patients with hepatocellular carcinoma.

Diagnostic value of hepatic artery perfusion fraction (HAF) combined with transforming growth factor-ß (TGF-ß) in the diagnosis of primary liver carcinoma (PLC) was evaluated. The clinical data of 128 PLC patients undergoing radical hepatectomy in Affiliated Hospital of Jining Medical University were regarded as the study group. Seventy-four healthy volunteers examined in Affiliated Hospital of Jining Medical University were collected as the control group. Double-antibody sandwich enzyme-linked immunosorbent assay was used to detect the expression level of serum TGF-ß. The upper abdomen of the subjects was scanned by a 64-slice spiral CT, and the perfusion parameters were analyzed and calculated. According to the HAF and the expression level of TGF-ß in the two groups, single and combined detection of TGF-ß and HAF parameters were detected, respectively, by ROC curve. The expression of TGF-ß in serum of the study group was higher than that of the control group (P<0.05). The expression level of serum TGF-ß was closely related to total bilirubin, ascites, TNM stage, prothrombin time and tumor diameter. Blood flow (BF), blood volume (BV), permeability surface (PS), HAF and other perfusion parameters in the study group were higher than those in the control group (P<0.05). The specificity and sensitivity of TGF-ß expression level in diagnosing PLC were 73 and 93%, respectively; the specificity and sensitivity of HAF parameter in diagnosing PLC were 73 and 100%, respectively; the specificity and sensitivity of HAF parameter combined with TGF-ß expression level were 84 and 100%, respectively. TGF-ß is highly expressed in serum of PLC patients; HAF parameter combined with TGF-ß expression level can improve the specificity and has an important value in the diagnosis of PLC, which is worthy of clinical promotion.

Evaluation of Placental Perfusion Based on Intravoxel Incoherent Motion Diffusion Weighted Imaging (IVIM-DWI) and Its Predictive Value for Late-Onset Fetal Growth Restriction.

Objective The aim of this study was to investigate placental blood perfusion in middle and late pregnancy and explore its predictive value for fetal growth restriction (FGR). Methods All pregnant women included in the study were examined using placental intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI). Three IVIM parameters (D, f, D*) were obtained for each pregnant woman and analyzed using Image J software. Perfusion fraction f is a radiological marker of placental perfusion. The pulsatility index (PI) of the uterine artery is used to indirectly evaluate placental function. Results f-values were significantly lower in the late-onset FGR group compared to the normal late pregnancy group (19.07 vs. 27.78%). In addition, uterine artery PI values were markedly increased in the late-onset FGR group compared to the normal late pregnancy group (1.96 vs. 1.03), and neonatal weight was significantly lower in the late-onset FGR group (2.75 vs. 3.18 kg). There was a significant positive correlation between f-value, uterine artery PI and neonatal weight (r = 0.968, p < 0.01; r = 0.959, p < 0.01). There was a significant negative correlation between f-value and age of gestation (r = - 0.534, p < 0.01). Conclusion Perfusion fraction f was strongly correlated with uterine artery blood flow resistance as measured by color Doppler and had a certain predictive value for late-onset FGR.

Quantitative parameters of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI): potential application in predicting pathological grades of pancreatic ductal adenocarcinoma.

BACKGROUND: The aim of this study was to compare intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) parameters such as standard apparent diffusion coefficient (ADCstandard), pure diffusion coefficient (Dslow), pseudodiffusion coefficient (Dfast) and perfusion fraction (ƒ) for differentiating pancreatic ductal adenocarcinoma (PDAC) with different pathological grades. METHODS: Institutional Review Board of our hospital approved this study protocol. Subjects comprised 38 PDACs confirmed by pathology. Pancreatic multiple b values DWI with 15 b values of 0, 10, 20, 40, 60, 80, 100, 150, 200, 400, 800, 1,000, 1200, 1,500, and 2,000 s/mm2 was performed using GE Discovery MR750 3.0T scanner. ADCstandard, Dslow, Dfast and ƒ values of all PDACs were calculated using mono- and bi-exponential models. Parameters of well/moderately differentiated and poorly differentiated PDAC were compared using Independent Sample t-test. P values <0.05 were considered significant. RESULTS: Mean Dslow value of well/moderately differentiated PDAC was significantly lower than that of poorly differentiated PDAC (0.540×10-3vs. 0.676×10-3 mm2/s, P<0.001). Mean ƒ value of well/moderately differentiated PDAC was significantly higher than that of poorly differentiated PDAC (60.3% vs. 38.4%, P<0.001). The area under curve value of ƒ in differentiating well/moderately differentiated PDAC from poorly differentiated PDAC was slightly higher than that of Dslow (0.894>0.865). When the Dslow value was less than or equal to 0.599×10-3 mm2/s, the sensitivity and specificity were 100% and 84.6% respectively. When ƒ value was greater than 49.6%, the sensitivity and specificity were 92.0% and 84.6% respectively. CONCLUSIONS: Dslow and ƒ derived from IVIM-DWI model can be used to distinguish well/moderately differentiated PDAC from poorly differentiated PDAC. And to serve this purpose, Dslow and ƒ have high diagnostic performance. IVIM-DWI is a promising and non-invasive tool for predicting pathological grade of PDAC.

Study of brain perfusion with IVIM-DWI in early hypertension / 医疗卫生装备

Objective To explore the value of intra-voxel incoherent motion diffusion weighted imaging(IVIM-DWI)in brain perfusion of early hypertensive patients. Methods Totally 36 hypertensive patients and 14 volunteers were recruited and scanned using routine MRI sequences including axial T2WI, T1WI, T2FLAIR, TOF-MRA and IVIM-DWI sequence. Perfusion-related diffusion coefficient (D*) values and perfusion fraction (f) values in various regions were measured separately.The independent sample t test was used to analyze the data.Results Compared with the volunteers,both D*values and f values in lenticular nucleus,thalamus,superior frontal gyrus,occipital lobe,genu of corpus callosum(CC)and posterior horns of periventricular WM, were found to be lower (P<0.05) in hypertensive patients. For other regions, there were no significant difference(P>0.05).Conclusion IVIM-DWI has the ability to detect subtle brain perfusion abnormalities at early stages of hypertension.It has an important value to the prevention and treatment of hypertensive encephalopathy.

Intravoxel incoherent motion MRI in the brain: Impact of the fitting model on perfusion fraction and lesion differentiability.

PURPOSE: To investigate the effect of the choice of the curve-fitting model on the perfusion fraction (fIVIM ) with regard to tissue type characterization, correlation with microvascular anatomy, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters. Several curve-fitting models coexist in intravoxel incoherent motion (IVIM) MRI to derive the (fIVIM ). MATERIALS AND METHODS: In all, 29 patients with brain lesions (12 gliomas, 11 meningiomas, three metastases, two gliotic scars, one multiple sclerosis) underwent IVIM-MRI (32 b-values, 0 to 2000 s/mm2 ) at 3T. fIVIM was determined by classic monoexponential, biexponential, and a novel nonnegative least squares (NNLS) fitting in 352 regions of interest (lesion-containing and normal-appearing tissue) and tested their correlation with DCE-MRI kinetic parameters and microvascular anatomy derived from 57 region of interest (ROI)-based biopsies and their capacities to differentiate histologically different lesions. RESULTS: fIVIM differed significantly between all three models and all tissue types (monoexponential confidence interval in percent [CI 3.4-3.8]; biexponential [CI 11.21-12.45]; NNLS [CI 2.06-2.60]; all P < 0.001). For all models an increase in fIVIM was associated with a shift to larger vessels and higher vessel area / tissue area ratio (regression coefficient 0.07-0.52; P = 0.04-0.001). Correlation with kinetic parameters derived from DCE-MRI was usually not significant. Only biexponential fitting allowed differentiation of both gliosis from edema and high- from low-grade glioma (both P < 0.001). CONCLUSION: The curve-fitting model has an important impact on fIVIM and its capacity to differentiate tissues. fIVIM may possibly be used to assess microvascular anatomy and is weakly correlated with DCE-MRI kinetic parameters. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1187-1199.

Intravoxel Incoherent Motion (IVIM) Diffusion Weighted Imaging (DWI) in the Periferic Prostate Cancer Detection and Stratification.

The aim of this study was to compare the Intravoxel Incoherent Motion (IVIM) parameters between healthy Peripheral Zone (PZ), Benign Prostatic Hyperplasia (BPH) and Prostate Cancer (PCa) and compare them to assess whether there was correlation with Gleason Score (GS) grading system. Thirty-one patients with suspect of PCa underwent 1.5T Multi-Parametric Magnetic Resonance Imaging (MP-MRI) with endorectal coil with a protocol including T2WI, DWI using 10 b values (0, 10, 20, 30, 50, 80, 100, 200, 400, 1000 s/mm2) and DCE. Monoexponential and IVIM model fits were used to calculate both apparent diffusion coefficient (ADC) and the following IVIM parameters: molecular diffusion coefficient (D), perfusion-related diffusion coefficient (D*) and perfusion fraction (f). The ADC and D values were significantly lower in the PCa (0.70 ± 0.16 × 10-3 mm2/s and 0.88 ± 0.31 × 10-3 mm2/s) compared to those found in the PZ (1.22 ± 0.20 × 10-3 mm2/s and 1.78 ± 0.34 × 10-3 mm2/s) and in the BPH (1.53 ± 0.23 × 10-3 mm2/s and 1.11 ± 0.28 × 10-3 mm2/s). The D* parameter was significantly increased in the PCa (5.35 ± 5.12 × 10-3 mm2/s) compare to the healthy PZ (3.02 ± 2.86 × 10-3 mm2/s), instead there was not significantly difference in the PCa compare to the BPH (5.61 ± 6.77 × 10-3 mm2/s). The f was statistically lower in the PCa (9.01 ± 5.20%) compared to PZ (10.57 ± 9.30%), but not significantly different between PCa and BPH (9.29 ± 7.29%). The specificity, sensitivity and accuracy of T2WI associated with DWI and IVIM were higher (100, 98 and 99%, respectively) than for T2WI/DWI and IVIM alone (89, 92 and 90%, respectively). Only for ADC was found a statistical difference between low- and intermediate-/high-grade tumors. Adding IVIM to the MP-MRI could increase the diagnostic performance to detect clinically relevant PCa. ADC values have been found to have a rule to discriminate PCa reliably from normal areas and differed significantly in low- and intermediate-/high-grade PCa. In contrast, IVIM parameters were unable to distinguish between the different GS.

Hepatocellular carcinoma: IVIM diffusion quantification for prediction of tumor necrosis compared to enhancement ratios.

PURPOSE: To correlate intra voxel incoherent motion (IVIM) diffusion parameters of liver parenchyma and hepatocellular carcinoma (HCC) with degree of liver/tumor enhancement and necrosis; and to assess the diagnostic performance of diffusion parameters vs. enhancement ratios (ER) for prediction of complete tumor necrosis. PATIENTS AND METHODS: In this IRB approved HIPAA compliant study, we included 46 patients with HCC who underwent IVIM diffusion-weighted (DW) MRI in addition to routine sequences at 3.0 T. True diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (PF) and apparent diffusion coefficient (ADC) were quantified in tumors and liver parenchyma. Tumor ER were calculated using contrast-enhanced imaging, and degree of tumor necrosis was assessed using post-contrast image subtraction. IVIM parameters and ER were compared between HCC and background liver and between necrotic and viable tumor components. ROC analysis for prediction of complete tumor necrosis was performed. RESULTS: 79 HCCs were assessed (mean size 2.5 cm). D, PF and ADC were significantly higher in HCC vs. liver (p < 0.0001). There were weak significant negative/positive correlations between D/PF and ER, and significant correlations between D/PF/ADC and tumor necrosis (for D, r 0.452, p < 0.001). Among diffusion parameters, D had the highest area under the curve (AUC 0.811) for predicting complete tumor necrosis. ER outperformed diffusion parameters for prediction of complete tumor necrosis (AUC > 0.95, p < 0.002). CONCLUSION: D has a reasonable diagnostic performance for predicting complete tumor necrosis, however lower than that of contrast-enhanced imaging.