Slow Apparent Diffusion Coefficient Research Articles

Intravoxel incoherent motion diffusion-weighted imaging and dynamic contrast-enhanced MRI for predicting parametrial invasion in cervical cancer.

This study aimed to assess the predictive efficacy of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in parametrial invasion (PMI) in cervical cancer patients. A total of 83 cervical cancer patients (32 PMI-positive and 51 PMI-negative) retrospectively underwent pretreatment IVIM-DWI and DCE-MRI scans. IVIM-DWI parameters included apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*), and perfusion fraction (f). DCE-MRI parameters included volume transfer constant (Ktrans), flux rate constant (Kep), and fractional extravascular extracellular space volume (Ve). Logistic regression analyses were conducted to identify independent variables associated with PMI. Receiver operating characteristic curves were generated to assess the predictive performance of significant parameters. Multivariable analysis revealed that the MRI parameters D (odds ratio [OR]: 7.05; 95% CI 1.78-27.88; P = 0.005), D* (OR 6.58; 95% CI 1.49-29.10; P = 0.01), f (OR 5.12; 95% CI 1.23-21.37; P = 0.03), Ktrans (OR 4.60; 95% CI 1.19-17.81; P = 0.03), and Kep (OR 4.90; 95% CI 1.25-19.18; P = 0.02) were independent predictors of PMI in cervical cancer patients. The combined parameter incorporating these parameters demonstrated the highest performance in predicting PMI, yielding an area under the curve of 0.906, sensitivity of 84.4%, and specificity of 86.3%. The proposed combined parameter exhibited favorable performance in identifying PMI in cervical cancer patients.

Ultrahigh field diffusion magnetic resonance imaging uncovers intriguing microstructural changes in the adult zebrafish brain caused by Toll-like receptor 2 genomic deletion.

Toll-like receptor 2 (TLR2) belongs to the TLR protein family that plays an important role in the immune and inflammation response system. While TLR2 is predominantly expressed in immune cells, its expression has also been detected in the brain, specifically in microglia and astrocytes. Recent studies indicate that genomic deletion of TLR2 can result in impaired neurobehavioural function. It is currently not clear if the genomic deletion of TLR2 leads to any alterations in the microstructural features of the brain. In the current study, we noninvasively assess microstructural changes in the brain of TLR2-deficient (tlr2-/-) zebrafish using state-of-the art magnetic resonance imaging (MRI) methods at ultrahigh magnetic field strength (17.6 T). A significant increase in cortical thickness and an overall trend towards increased brain volumes were observed in young tlr2-/- zebrafish. An elevated T2 relaxation time and significantly reduced apparent diffusion coefficient (ADC) unveil brain-wide microstructural alterations, potentially indicative of cytotoxic oedema and astrogliosis in the tlr2-/- zebrafish. Multicomponent analysis of the ADC diffusivity signal by the phasor approach shows an increase in the slow ADC component associated with restricted diffusion. Diffusion tensor imaging and diffusion kurtosis imaging analysis revealed diminished diffusivity and enhanced kurtosis in various white matter tracks in tlr2-/- compared with control zebrafish, identifying the microstructural underpinnings associated with compromised white matter integrity and axonal degeneration. Taken together, our findings demonstrate that the genomic deletion of TLR2 results in severe alterations to the microstructural features of the zebrafish brain. This study also highlights the potential of ultrahigh field diffusion MRI techniques in discerning exceptionally fine microstructural details within the small zebrafish brain, offering potential for investigating microstructural changes in zebrafish models of various brain diseases.

Multiparametric MRI for Staging of Bowel Inflammatory Activity in Crohn's Disease with MUSE-IVIM and DCE-MRI: A Preliminary Study

To investigate if the combination of multishot diffusion imaging-based multiplexed sensitivity encoding intravoxel incoherent motion (MUSE-IVIM) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is feasible for staging Crohn's disease (CD) activity. A total of 65 CD patients were enrolled and analyzed in this retrospective study. The simplified endoscopic score for Crohn's disease (SES-CD) and magnetic resonance index of activity (MaRIA) were used as the reference. The MUSE-IVIM and DCE-MRI data were acquired at 3.0-T MRI scanner and processed by two radiologists. Three MUSE-IVIM parameters: fast apparent diffusion coefficient (ADCfast), slow apparent diffusion coefficient (ADCslow), and the fractional perfusion (Fraction of ADCfast), as well as four DCE-MRI parameters: volume transfer constant (Ktrans), rate constant (Kep), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp) were generated. Intraclass correlation coefficient (ICC), non-parametric test (Kruskal-Wallis H and Mann-Whitney U), logistic regression, receiver operating characteristic analysis, Delong test, and Spearman's correlation test were performed. According to SES-CD, 116 ileocolonic segments with CD lesions were identified as: inactive, mild, and moderate to severe. With multivariable logistic regression analysis, ADCfast (p<0.001), Fraction of ADCfast (p=0.005), Ktrans (p<0.001) and Kep (p=0.003) were identified as significant factors for differentiating among the three groups. Binary logistic analyses identified ADCfast (p=0.001), Ktrans (p=0.014), and Kep (p=0.029) as independent predictors for the active status. The combination of ADCfast, Ktrans, and Kep performed better than MaRIA score (p=0.028), for differentiating inactive and active status. MaRIA score was positively correlated with ADCfast (p<0.001), Ktrans (p<0.001), Kep (p<0.001), and Ve (p=0.001), however, negatively correlated with Fraction of ADCfast (p<0.001). The combination of MUSE-IVIM and DCE-MRI has been demonstrated to accurately stage inflammatory activity in CD.

Early assessment of acute kidney injury in severe acute pancreatitis with multimodal DWI: an animal model.

To evaluate the feasibility of multimodal diffusion-weighted imaging (DWI) for detecting the occurrence and severity of acute kidney injury (AKI) caused by severe acute pancreatitis (SAP) in rats. SAP was induced in thirty rats by the retrograde injection of 5.0% sodium taurocholate through the biliopancreatic duct. Six rats underwent MRI of the kidneys 24h before and 2, 4, 6, and 8h after this AKI model was generated. Conventional and functional MRI sequences were used, including intravoxel incoherent motion imaging (IVIM), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DTI). The main DWI parameters and histological results were analyzed. The fast apparent diffusion coefficient (ADC) of the renal cortex was significantly reduced at 2h, as was the fractional anisotropy (FA) value of the renal cortex on DTI. The mean kurtosis (MK) values for the renal cortex and medulla gradually increased after model generation. The renal histopathological score was negatively correlated with the medullary slow ADC, fast ADC, and perfusion scores for both the renal cortex and medulla, as were the ADC and FA values of the renal medulla in DTI, whereas the MK values of the cortex and medulla were positively correlated (r = 0.733, 0.812). Thus, the cortical fast ADC, medullary MK, FADTI, and slow ADC were optimal parameters for diagnosing AKI. Of these parameters, cortical fast ADC had the highest diagnostic efficacy (AUC = 0.950). The fast ADC of the renal cortex is the core indicator of early AKI, and the medullary MK value might serve as a sensitive biomarker for grading renal injury in SAP rats. The multimodal parameters of renal IVIM, DTI, and DKI are potential beneficial for the early diagnosis and severity grading of renal injury in SAP patients. • The multimodal parameters of renal DWI, including IVIM, DTI, and DKI, may be valuable for the noninvasive detection of early AKI and the severity grading of renal injury in SAP rats. • Cortical fast ADC, medullary MK, FA, and slow ADC are optimal parameters for early diagnosis of AKI, and cortical fast ADC has the highest diagnostic efficacy. • Medullary fast ADC, MK, and FA as well as cortical MK are useful for predicting the severity grade of AKI, and the renal medullary MK value exhibits the strongest correlation with pathological scores.

Image Improved Intravoxel Incoherent Motion MRI With Optimized Trigger Delays Based on Strain Curve Analysis to Evaluate Myocardial Microvascular Dysfunction of Exertional Heat Illness.

Intravoxel incoherent motion (IVIM) MRI has not been widely used and its role in evaluating exertional heat illness (EHI)-related myocardial involvement remains unknown. 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. Prospective. A total of 42 male EHI patients (median age: 21 years) and 22 age- and sex-matched healthy controls (HC). A 3-T, diffusion-weighted spin-echo echo-planar-imaging sequence. 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. 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. 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%. 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. 2. Stage 3.

Intravoxel incoherent motion to assess brain microstructure and perfusion in patients with end-stage renal disease.

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

Assessment of Isocitrate Dehydrogenase 1 Genotype and Cell Proliferation in Gliomas Using Multiple Diffusion Magnetic Resonance Imaging.

Objectives: To compare the efficacy of parameters from multiple diffusion magnetic resonance imaging (dMRI) for prediction of isocitrate dehydrogenase 1 (IDH1) genotype and assessment of cell proliferation in gliomas.Methods: Ninety-one patients with glioma underwent diffusion weighted imaging (DWI), multi-b-value DWI, and diffusion kurtosis imaging (DKI)/neurite orientation dispersion and density imaging (NODDI) on 3.0T MRI. Each parameter was compared between IDH1-mutant and IDH1 wild-type groups by Mann–Whitney U test in lower-grade gliomas (LrGGs) and glioblastomas (GBMs), respectively. Further, performance of each parameter was compared for glioma grading under the same IDH1 genotype. Spearman correlation coefficient between Ki-67 labeling index (LI) and each parameter was calculated.Results: The diagnostic performance was better achieved with apparent diffusion coefficient (ADC), slow ADC (D), fast ADC (D∗), perfusion fraction (f), distributed diffusion coefficient (DDC), heterogeneity index (α), mean diffusivity (MD), mean kurtosis (MK), and intracellular volume fraction (ICVF) for distinguishing IDH1 genotypes in LrGGs, with statistically insignificant AUC values from 0.750 to 0.817. In GBMs, no difference between the two groups was found. For IDH1-mutant group, all parameters, except for fractional anisotropy (FA) and D∗, significantly discriminated LrGGs from GBMs (P < 0.05). However, for IDH1 wild-type group, only ADC statistically discriminated the two (P = 0.048). In addition, MK has maximal correlation coefficient (r = 0.567, P < 0.001) with Ki-67 LI.Conclusion: dMRI-derived parameters are promising biomarkers for predicting IDH1 genotype in LrGGs, and MK has shown great potential in assessing glioma cell proliferation.

Application Value of Mathematical Models of Diffusion-Weighted Magnetic Resonance Imaging in Differentiating Breast Cancer Lesions.

Objective To determine the application value of the mono-exponential model, dual-exponential model, and stretched-exponential model of MRI with diffusion-weighted imaging (DWI) in breast cancer (BC) lesions. Methods Totally 64 cases with BC admitted to our hospital between June 2019 and October 2020 were enrolled in this study. They had 71 lesions in total, including 40 benign tumor lesions (including 9 breast cyst lesions) and 31 malignant tumor lesions. After DWI examination, with normal glands as control, mono-exponential model (ADC) map, dual-exponential model (Standard-ADC) map, slow apparent diffusion coefficient (Slow-ADC) map, fast-apparent diffusion coefficient (Fast-ADC) map, and stretched-exponential model (DDC) map were processed, and corresponding values were generated. Then, the situation and significance of each parameter in breast cysts, benign breast tumor lesions, and malignant tumor lesions were analyzed. Results The values of ADC, Standard-ADC, and DDC of breast cysts were higher than those of normal glands (all P < 0.05), and the values of ADC and DDC of benign breast tumor lesions were lower than those of normal glands (P < 0.05). In addition, malignant breast tumor lesions had lower values of ADC, Standard-ADC, Slow-ADC, and DDC and a higher Fast-ADC value compared to normal glands (all P < 0.05). Compared with benign tumor lesions, malignant tumor lesions had lower values of ADC, Standard-ADC, Slow-ADC, and DDC and a higher value of Fast-ADC (all P < 0.05). Moreover, the receiver operating characteristic (ROC) curve-based analysis revealed that all the above models could be adopted to effectively evaluate the deterioration of benign breast tumor lesions (all P < 0.05), and DDC value had the most significant diagnostic effect on malignant tumor lesions (P < 0.05). Conclusion Both dual-exponential model and stretched-exponential model of DWI can help effectively evaluate the progression of benign breast tumors, and the stretched-exponential model is more effective in the diagnosis of malignant breast tumors. These models are of great help to the future clinical diagnosis of BC.

A study of the correlations between IVIM-DWI parameters and the histologic differentiation of hepatocellular carcinoma

The present study aimed to investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in the preoperative prediction of the histologic differentiation of hepatocellular carcinoma (HCC). Seventy HCC patients were scanned with a 3.0 T magnetic resonance scanner. The values of apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*), and the fraction of the fast apparent diffusion coefficient (f) were measured. Analysis of variance was used to compare the differences in parameters between groups with different degrees of histologic differentiation. p < 0.05 was considered statistically significant. Receiver operating characteristic (ROC) curves were used to analyse the efficacy of IVIM-DWI parameters for predicting the histologic differentiation of HCC. The ADC and D values for well, moderately and poorly differentiated HCC were 1.35 ± 0.17 × 10−3 mm2/s, 1.16 ± 0.17 × 10−3 mm2/s, 0.98 ± 0.21 × 10−3 mm2/s, and 1.06 ± 0.15 × 10−3 mm2/s, 0.88 ± 0.16 × 10−3 mm2/s, 0.76 ± 0.18 × 10−3 mm2/s, respectively, and all differences were significant. The D* and f values of the three groups were 32.87 ± 14.70 × 10−3 mm2/s, 41.68 ± 17.90 × 10−3 mm2/s, 34.54 ± 18.60 × 10−3 mm2/s and 0.22 ± 0.07, 0.23 ± 0.08, 0.18 ± 0.07, respectively, with no significant difference. When the cut-off values of ADC and D were 1.25 × 10−3 mm2/s and 0.97 × 10−3 mm2/s, respectively, their diagnostic sensitivities and specificities for distinguishing well differentiated HCC from moderately differentiated and poorly differentiated HCC were 73.3%, 85.5%, 86.7%, and 78.2%, and their areas under the ROC curve were 0.821 and 0.841, respectively. ADC and D values can be used preoperatively to predict the degree of histologic differentiation in HCC, and the D value has better diagnostic value.

A Correlative Study Between IVIM-DWI Parameters and the Expression Levels of Ang-2 and TKT in Hepatocellular Carcinoma.

BackgroundNoninvasive evaluation of the expression of angiopoietin-2 (Ang-2) and transketolase (TKT) in hepatocellular carcinoma (HCC) is of great significance for the clinical development of individualized treatment plans. However, the correlation between intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and the expression of Ang-2 and TKT has not been reported. We sought to investigate the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs.MethodsConventional non-enhanced magnetic resonance imaging (MRI) and IVIM-DWI and dynamic contrast MRI were performed for 61 patients with HCC before surgical treatment. Various IVIM-DWI parameters, such as apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*) and fraction of fast apparent diffusion coefficient (f), were calculated using Function-MADC software. Expression levels of Ang-2 and TKT in HCC were detected via immunohistochemical staining and classified into two grades. Independent sample t tests were used to compare differences in parameters between the two groups. The Spearman rank correlation test was used to analyze the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs.ResultsThe D* and f values were significantly higher in the high Ang-2 group than in the low Ang-2 group; there were no obvious between-group differences in ADC and D. Ang-2 expression was positively correlated with D* and f but not with ADC and D. The ADC and D values were significantly lower in the high TKT group than in the low TKT group, whereas the between-group differences for D* and f were not significant. TKT expression was negatively correlated with ADC and D but not with D* and f.ConclusionsIVIM-DWI can be used to evaluate Ang-2 and TKT expression in HCC.

Denoising and Multiple Tissue Compartment Visualization of Multi-b-Valued Breast Diffusion MRI.

Multi-b-valued/multi-shell diffusion provides potentially valuable metrics in breast MRI but suffers from low signal-to-noise ratio and has potentially long scan times. To investigate the effects of model-based denoising with no loss of spatial resolution on multi-shell breast diffusion MRI; to determine the effects of downsampling on multi-shell diffusion; and to quantify these effects in multi-b-valued (three directions per b-value) acquisitions. Prospective ("fully-sampled" multi-shell) and retrospective longitudinal (multi-b). One normal subject (multi-shell) and 10 breast cancer subjects imaging at four timepoints (multi-b). 3T multi-shell acquisition and 1.5T multi-b acquisition. The "fully-sampled" multi-shell acquisition was retrospectively downsampled to determine the bias and error from downsampling. Mean, axial/parallel, radial diffusivity, and fractional anisotropy (FA) were analyzed. Denoising was applied retrospectively to the multi-b-valued breast cancer subject dataset and assessed subjectively for image noise level and tumor conspicuity. Parametric paired t-test (P < 0.05 considered statistically significant) on mean and coefficient of variation of each metric-the apparent diffusion coefficient (ADC) from all b-values, fast ADC, slow ADC, and perfusion fraction. Paired and two-sample t-tests for each metric comparing normal and tumor tissue. In the multi-shell data, denoising effectively suppressed FA (-45% to -78%), with small biases in mean diffusivity (-5% in normal, +23% in tumor, and -4% in vascular compartments). In the multi-b data, denoising resulted in small biases to the ADC metrics in tumor and normal contralateral tissue (by -3% to +11%), but greatly reduced the coefficient of variation for every metric (by -1% to -24%). Denoising improved differentiation of tumor and normal tissue regions in most metrics and timepoints; subjectively, image noise level and tumor conspicuity were improved in the fast ADC maps. Model-based denoising effectively suppressed erroneously high FA and improved the accuracy of diffusivity metrics. 3 TECHNICAL EFFICACY STAGE: 1.

Do magnetic resonance imaging manifestations of skeletal system improve after treatment of Gaucher disease?

ObjectivesSkeletal lesions are the most serious complications of Gaucher disease (GD). The pathological changes of skeletal system are complex, which seriously affects the quality of life. The aim was to investigate whether the skeletal system improved in quantitative imaging after treatment with enzyme replacement therapy (ERT). MethodsMagnetic resonance imaging (MRI) of the vertebrae and femur was performed in 40 patients and 34 healthy volunteers. The scan sequences include iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) and intravoxel incoherent motion imaging (IVIM). Statistical data were analyzed by using t-test. ResultsAs for the fat fraction (FF) and R2*, there were significant differences in FF and R2* of vertebrae and left femur. As for the standard apparent diffusion coefficient (sADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*) and fraction of fast apparent diffusion coefficient (f) of vertebrae and femur. Only D of vertebrae, sADC and f of left femur and sADC of right femur had statistical difference. ConclusionThe quantitative imaging of skeletal system lesions have certain characteristics. The lesions in the skeletal system of patients treated with ERT has been improved to some extent, but it is still different from that in normal people.

The added value of intravoxel incoherent motion diffusion weighted imaging parameters in differentiating high-grade pancreatic neuroendocrine neoplasms from pancreatic ductal adenocarcinoma.

The aim of the present study was to investigate the potential significance of intravoxel incoherent motion (IVIM)-diffusion weighted imaging (DWI) in differentiating high-grade pancreatic neuroendocrine neoplasms (pNENs) from pancreatic ductal adenocarcinoma (PDAC). A total of 50 patients, including 37 patients with PDAC and 13 patients with high-grade pNENs, underwent pancreatic multiple b-values DWI with 15 b-values including 0, 10, 20, 40, 60, 80, 100, 150, 200, 400, 800, 1,000, 1,200, 1,500 and 2,000 sec/mm2. Standard apparent diffusion coefficient (ADCstandard) and IVIM parameter [slow apparent diffusion coefficient (Dslow), fast apparent diffusion coefficient (Dfast), fraction of fast apparent diffusion coefficient (ƒ)] values of PDAC and pNENs were compared. P<0.05 was considered to indicate a statistically significant difference. Receiver operating characteristics analysis was performed in order to evaluate the diagnostic potential of IVIM parameters for differentiating high-grade pNENs from PDAC. Dslow of pNENs was significantly lower compared with that of PDAC (0.460 vs. 0.579×10−3 mm2/sec; P=0.001). Dfast of pNENs was significantly higher compared with that of PDAC (13.361 vs. 4.985×10−3 mm2/sec; P<0.001). Area under the curve of Dslow, Dfast and combined Dslow and Dfast was 0.793, 0.863 and 0.885 respectively. The specificity and sensitivity of Dslow≤0.472×10−3 mm2/sec were 97.3 and 53.9%, respectively, for differentiating high-grade pNENs from PDAC. The specificity and sensitivity of Dfast >9.58×10−3 mm2/sec were 91.9 and 69.2%, respectively, for differentiating high-grade pNENs from PDAC. When Dslow and Dfast were combined, the specificity and sensitivity for differentiating high-grade pNENs from PDAC were 76.9 and 100%, respectively. Taken together, these results indicated that the diffusion-associated parameter Dslow and the perfusion-associated parameter Dfast of IVIM-DWI may differentiate high-grade pNENs from PDAC with high diagnostic accuracy, and that IVIM-DWI may be a valuable biomarker in differentiating pancreatic neoplasms.

Slow component apparent diffusion coefficient for prostate cancer: Comparison and correlation with pharmacokinetic evaluation from dynamic contrast-enhanced MR imaging

PurposeDynamic contrast enhancement (DCE)-MRI has high diagnostic performance of prostate cancer. However, it is preferable to avoid the use of MRI contrast media. A study reported that the diagnosability of the wash-in index of DCE-MRI was equivalent to the intravoxel incoherent motion of the diffusion weighted image.The purpose of this study was to examine the correlation between the slow component apparent diffusion coefficient (ADC) and the wash-out index of the DCE. Materials and methodsThirty-eight patients diagnosed with prostate cancer by biopsy were enrolled in this study. The fast and slow component ADCs of the DWI were calculated for 76 points of the tumor and the contralateral normal parts. Furthermore, the wash-in and wash-out indices of the DCE-MRI were calculated. The correlations for each calculated index were compared. ResultsThere was a significant difference between the tumor and the contralateral normal parts for both fast (p = 0.03) and slow component (p < 0.01) ADCs. In addition, the slow component ADC was correlated with the wash-out index (r = 0.64). ConclusionThe slow component ADC was correlated with the wash-out index, and may, therefore, be a suitable substitute for DCE-MRI.

Study on the significance of intravoxel incoherent motion quantitative index combined with time-signal intensity curve in the early diagnosis of residual lesions in non-small cell lung cancer after argon-helium cryosurgery

Objective: To study the application of intravoxel incoherent motion (IVIM) quantitative index combined with time-signal intensity curve (TIC) of dynamic contrast enhanced 3.0T magnetic resonance in the early precise diagnosis of residual lesions in non-small cell lung cancer (NSCLC) after argon-helium cryosurgery. Methods: One hundred NSCLC patients who underwent argon-helium cryosurgery were collected and divided into the residual group (21 cases) and non-residual group (79 cases) according to the result of needle biopsy and follow-up. The apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (sADC), fast apparent diffusion coefficient (fADC), fraction of fast apparent diffusion coefficient (ffADC) and TIC type of IVIM quantitative index between the two groups were compared at 7 days and 1 month after argon-helium cryosurgery, respectively. The diagnosis performance of each quantitative index was analyzed by receiver operating characteristic (ROC) curve and the best cut-off value was computed. The specificity and sensitivity of TIC types were calculated as diagnostic criteria. The diagnosis performance of IVIM quantitative index combined with TIC type was evaluated and compared with the conventional MRI and DWI. Results: The differences of ADC, sADC and ffADC at 7 days and 1 month after argon-helium cryosurgery between the residual group and non-residual group were statistically significant (all P<0.05), in which the diagnosis performance of sADC and ffADC were better. The AUC of sADC and ffADC at 7 days after argon-helium cryosurgery were 0.861 and 0.895, the sensitivity were 81.0% and 90.5%, and the specificity were 77.2% and 73.4%, respectively. The AUC of sADC and ffADC at 1 month after argon-helium cryosurgery were 0.836 and 0.883, the sensitivity were 100.0% and 76.2%, and the specificity were 58.2% and 89.9%, respectively. The diagnosis performance of TIC type Ⅱ&Ⅲ was best. The sensitivity and specificity were 80.9% and 58.2% at 7 days after treatment, 85.7% and 62.0% at 1 month after treatment, respectively. At 7 days after treatment, the sensitivity and specificity of IVIM combined with TIC were 97.5% and 85.7%, while at 1 month after treatment, the sensitivity and specificity of IVIM combined with TIC were 97.5% and 90.5%, respectively. The diagnosis performance of IVIM quantitative index combined with TIC type was better than conventional MRI and DWI. Conclusion: The combination of IVIM quantitative index and TIC type can be used in the early diagnosis of residual lesions after argon-helium cryosurgery for NSCLC, whose effect is better than conventional MRI and DWI.

Apparent diffusion coefficient changes in human brain during sleep – Does it inform on the existence of a glymphatic system?

The role of sleep in brain physiology is poorly understood. Recently rodent studies have shown that the glymphatic system clears waste products from brain more efficiently during sleep compared to wakefulness due to the expansion of the interstitial fluid space facilitating entry of cerebrospinal fluid (CSF) into the brain. Here, we studied water diffusivity in the brain during sleep and awake conditions, hypothesizing that an increase in water diffusivity during sleep would occur concomitantly with an expansion of CSF volume - an effect that we predicted based on preclinical findings would be most prominent in cerebellum. We used MRI to measure slow and fast components of the apparent diffusion coefficient (ADC) of water in the brain in 50 healthy participants, in 30 of whom we compared awake versus sleep conditions and in 20 of whom we compared rested-wakefulness versus wakefulness following one night of sleep-deprivation. Sleep compared to wakefulness was associated with increases in slow-ADC in cerebellum and left temporal pole and with decreases in fast-ADC in thalamus, insula, parahippocampus and striatal regions, and the density of sleep arousals was inversely associated with ADC changes. The CSF volume was also increased during sleep and was associated with sleep-induced changes in ADCs in cerebellum. There were no differences in ADCs with wakefulness following sleep deprivation compared to rested-wakefulness. Although we hypothesized increases in ADC with sleep, our findings uncovered both increases in slow ADC (mostly in cerebellum) as well as decreases in fast ADC, which could reflect the distinct biological significance of fast- and slow-ADC values in relation to sleep. While preliminary, our findings suggest a more complex sleep-related glymphatic function in the human brain compared to rodents. On the other hand, our findings of sleep-induced changes in CSF volume provide preliminary evidence that is consistent with a glymphatic transport process in the human brain.

Intravoxel incoherent motion magnetic resonance imaging for breast cancer: A comparison with benign lesions and evaluation of heterogeneity in different tumor regions with prognostic factors and molecular classification.

The objective of the present study was to compare the differentiation between breast cancer and benign breast lesions and study regional distribution characteristics in various subtypes of breast cancer using intravoxel incoherent motion (IVIM) parameters. This retrospective study involved 119 patients with breast cancer and 22 patients with benign breast lesions, who underwent 3.0T breast magnetic resonance imaging examinations. The apparent diffusion coefficient (ADC) and IVIM parameters (slow ADC, fast ADC and fraction of fast ADC) were obtained from patients with breast cancer and benign lesions using diffusion-weighted imaging (DWI) with b-values of 0, 50, 100, 150, 200, 400, 500, 1,000 and 1,500 sec/mm2. Compared with patients with benign breast lesions, patients with breast cancer exhibited decreased ADC (P<0.001), slow ADC (P<0.001) and fast ADC (P<0.001) values, and higher fraction of fast ADC (P<0.001) values. Tumors with metastatic axillary lymph nodes demonstrated increased fraction of fast ADC values (P<0.001) and decreased slow ADC values (P<0.001) compared with tumors without metastatic axillary lymph nodes. The Fast ADC values of tumor tissues in estrogen receptor (ER) and progesterone receptor (PR) negative groups were higher than in positive groups (P<0.001), and the slow ADC values of tumor tissues were lower in ER and PR negative groups than positive groups (P<0.001). Luminal B (HER2- negative) tumor (P<0.001) and peritumor (P<0.001) tissues exhibited decreased fraction of fast ADC values, in comparison with other subtypes. Triple-negative breast cancer (TNBC) tumor tissue exhibited increased fast ADC (P<0.001) and fraction of fast ADC values (P<0.001), and decreased slow ADC values (P<0.001), when compared with other subtypes. The TNBC tumor edge tissues had increased fraction of fast ADC values compared with other subtypes (P<0.01) and TNBC tumor tissues (P<0.05). Therefore, the IVIM parameters of tumor, tumor edge and peritumor tissues in various subtypes of breast cancer may be useful for differentiation of breast cancer subtypes and to assess the invasive extent of the tumors.

Restriction spectrum imaging of white matter and its relation to neurological disability in multiple sclerosis

Background: Restriction spectrum imaging (RSI) is a recently introduced magnetic resonance imaging diffusion technique. The utility of RSI in multiple sclerosis (MS) is unknown. Objective: To investigate the association between RSI-derived parameters and neurological disability in MS. Methods: Seventy-seven relapsing–remitting MS patients were scanned with RSI on a 3-T scanner. RSI-derived parameters: fast and slow apparent diffusion coefficient (sADC), fractional anisotropy, restricted fractional anisotropy, neurite density (ND), cellularity, extracellular water fraction, and free water fraction, were obtained in white matter lesions (WML) and normal appearing white matter (NAWM). Patients were divided into three groups according to their expanded disability status scale (EDSS): with minimal, low, and substantial disability (<2.5, 2.5–3, and >3, respectively). Group comparisons and correlation analyses were performed. Results: All tested RSI-derived parameters differed between WML and NAWM (p < 0.001 for all pairwise comparisons). The sADC in WML showed largest difference across disability subgroups (analysis of variance (ANOVA): F = 5.1, η2 = 0.12, p = 0.008). ND in NAWM showed strongest correlation with disability (ϱ = –0.39, p < 0.001). Conclusion: The strongest correlation with EDSS of ND obtained in NAWM indicates that processes outside lesions are important for disability in MS. Our study suggests that RSI-derived parameters may help understand the “clinico-radiological paradox” and improve disease monitoring in MS.

Application study of differentiating malignant benign from breast lesions using multiple b-value DWI

Objective: To explore the diagnostic value of multi b-value DWI (MB-DWI) in the identification of benign and malignant breast lesions. Methods: From October 2013 to December 2015, a total of 54 cases from Ningbo Medical Center Lihuili Hospital (22 benign cases with a total of 24 lesions, 32 malignant cases with a total of 38 lesions) were examined with conventional MR scan, single b-value DWI, and multiple b-value DWI (0, 10, 20, 30, 50, 100, 200, 400, 800, 1 200, 2 000, 3 000 s/mm(2)). GE ADW4.5 workstation was used to calculate the value of standard apparent diffusion coefficient (ADC(standard)), slow apparent diffusion coefficient(ADC(slow)), fast apparent diffusion coefficient (ADC(fast)) and fraction of ADC(fast)(f(fast)). Receiver operating characteristic (ROC)curve was performed to evaluate those MB-DWI parameters above. Results: The ADC(standard), ADC(slow) and f(fast) value of malignant group were (0.761±0.166)×10(-3) mm(2)/s, (0.593±0.144)×10(-3) mm(2)/s, 0.330±0.099 respectively, which were significantly lower than those of benign group (all P<0.01), while the ADC(fast) value of malignant group was 4.379×10(-3) mm(2)/s, significantly higher than that of benign group(P<0.01). The area under curve (AUC) of f(fast) and ADC(standard) were 0.799, 0.786 respectively and there is no statistically significant difference.The AUC of ADC(slow), ADC(fast) were 0.719, 0.727, which were statistically significant different from the value of f(fast) or ADC(standard)(all P<0.01). Conclusions: All the parameters in MB-DWI can be used to distinguish benign from malignant breast lesions.The f(fast) and ADC(standard) value have higher diagnostic value in the identification of benign and malignant breast lesions.

Predictive values of diffusion-weighted imaging and perfusion-weighted imaging in evaluating the efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma.

This study explored the predictive values of diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) in evaluating the efficacy of transcatheter arterial chemoembolization (TACE) for patients with hepatocellular carcinoma (HCC). A total of 118 HCC patients treated with TACE were selected from April 2013 to November 2015. T1-weighted imaging (T1WI)/T2-weighted imaging (T2WI), DWI, and PWI were performed on all patients before and after TACE. Efficacy was evaluated according to modified Response Evaluation Criteria in Solid Tumors 1.1. Receiver operating characteristic curve was used to evaluate the diagnostic power of quantitative DWI and PWI parameters in evaluating the efficacy of TACE for HCC patients. Among the 118 HCC patients, there were 17 cases (14.4%) with complete response, 50 cases (42.4%) with partial response, 28 cases (23.7%) with stable disease, and 23 cases (19.5%) with progressive disease. There were 67 patients in the effective group (complete response + partial response) and 51 patients in the ineffective group (stable disease + progressive disease). Before TACE, there were significant differences in maximum tumor diameter (MTD), apparent diffusion coefficient (ADC), slow ADC (Dslow), fast ADC (Dfast), transfer constant of vessel at the maximum level (Ktrans), and rate constant of backflux (Kep) between the effective and ineffective groups (all P<0.05). After TACE, the effective group exhibited lower MTD, Dfast, and Kep and higher ADC and Dslow than the ineffective group (all P<0.05). Tumor regression rate negatively correlated with MTD, Ktrans, Kep, and Dfast but positively correlated with ADC and Dslow. Receiver operating characteristic curve analysis suggested that the area under the curve of ADC, Dslow, Dfast, Ktrans, and Kep were 0.869, 0.833, 0.812, 0.802, and 0.809, respectively. In conclusion, these results suggest that quantitative DWI and PWI parameters might be useful in evaluating the efficacy of TACE in the treatment of HCC patients.