DWI Signal Research Articles

DWI Hyperintensity in the Fornix Fimbria on MRI in Children.

The fornix-fimbria complex is mainly involved in emotions and memory. In brain MR imaging studies of young children, we have occasionally noted DWI hyperintensity in this region. The significance of this finding remains unclear. This study evaluated the DWI signal in the fornix-fimbria complex of children 0-2 years of age, including the frequency of signal hyperintensity and clinical context. Brain MR imaging of 714 children 0-2 years of age (mean, 11 months), performed between September 2018 and May 2021, was reviewed and evaluated for DWI signal changes in the fornix-fimbria. All children with available MR imaging studies including DWI were included. Children with poor image quality, poor visualization of the fornix-fimbria region, and missing medical data were excluded. Additional imaging findings were also evaluated. Demographic data were retrieved from the medical files. We compared the ADC values of the fimbria and fornix between children with and without signal changes. The unpaired 2-tailed Student t test and χ2 test were used for statistical analysis. DWI signal hyperintensity of the Fornix-fimbria complex was noted in 53 (7.4%) children (mean age, 10 months). Their mean ADC values were significantly lower than those of the children with normal DWI findings (P < .05). About half of the children had otherwise normal MR imaging findings. When detected, the most common abnormality was parenchymal volume loss (15%). The most common indication for imaging was seizures (26.5%). DWI hyperintensity in the fornix-fimbria complex was detected in 7.4% of children 0-2 years of age. The etiology is not entirely clear, possibly reflecting a transient phenomenon.

Multiparametric bone MRI can improve CT-guided bone biopsy target selection in cancer patients and increase diagnostic yield and feasibility of next-generation tumour sequencing

ObjectivesTo evaluate whether multiparametric bone MRI (mpBMRI) utilising a combination of DWI signal, ADC and relative fat-fraction (rFF) can identify bone metastases, which provide high diagnostic biopsy yield and next-generation genomic sequencing (NGS) feasibility.MethodsA total of 150 CT-guided bone biopsies performed by interventional radiologists (3/2013 to 2/2021) at our centre were reviewed. In 43 patients, contemporaneous DWI and rFF images, calculated from 2-point T1w Dixon MRI, were available. For each biopsied lesion, a region of interest (ROI) was delineated on ADC and rFF images and the following MRI parameters were recorded: visual classification of DWI signal intensity (SI), mean, median, 10th and 90th centile ADC and rFF values. Non-parametric tests were used to compare values between tumour positive/negative biopsies and feasible/non-feasible NGS, with p-values < 0.05 deemed significant.ResultsThe mpBMRI combination high DWI signal, mean ADC < 1100 µm2/s and mean rFF < 20% identified tumour-positive biopsies with 82% sensitivity, 80% specificity, a positive predictive value (PPV) of 93% (p = 0.001) and NGS feasibility with 91% sensitivity, 78% specificity and 91% PPV (p < 0.001). The single MRI parameters DWI signal, ADC and rFF failed to distinguish between tumour-positive and tumour-negative biopsies (each p > 0.082). In NGS feasible biopsies, mean and 90th centile rFF were significantly smaller (each p < 0.041). Single ADC parameters did not show significant difference regarding NGS feasibility (each p > 0.292).ConclusionsMpBMRI utilising the combination of DWI signal, ADC and rFF can identify active bone metastases, which provide biopsy tissue with high diagnostic yield and NGS feasibility.Key Points• Multiparametric bone MRI with diffusion-weighted and relative fat-fraction images helps to identify active bone metastases suitable for CT-guided biopsy.• Target lesions for CT-guided bone biopsies in cancer patients can be chosen with greater confidence.• CT-guided bone biopsy success rates, especially yielding sufficient viable tissue for advanced molecular tissue analyses, can be improved.

Targeting visualization of malignant tumor based on the alteration of DWI signal generated by hTERT promoter–driven AQP1 overexpression

To specifically diagnose malignant tumors in DWI using the human telomerase reverse transcriptase (hTERT) promoter-driven AQP1 expression. The human telomerase reverse transcriptase (hTERT) promoter-driven AQP1 gene overexpression lentivirus system (hTERT-AQP1) and cytomegalovirus (CMV) promoter-driven AQP1 gene overexpression lentivirus system (CMV-AQP1) were prepared, and transduced into telomerase-positive and -negative cells. The AQP1 expression and DWI signal intensity (SI) change in transduced cells were analyzed. Balb/C nude mice subcutaneous xenograft models derived from lentivirus-transduced telomerase-positive and -negative cells were used to evaluate AQP1 expression and DWI SI change in vivo. We further established another group of subcutaneous xenograft model using pristine telomerase-positive and -negative cells, followed by injecting the lentiviral vectors intratumorally or intravenously, to determine the malignant tumor-targeted imaging of hTERT-AQP1. The hTERT-AQP1 and CMV-AQP1 were successfully prepared. After transduction, hTERT-AQP1 could induce the specific overexpression of AQP1 in telomerase-positive cells. Compared with untransduced cells, all CMV-AQP1-pretransduced cells and hTERT-AQP1-pretransduced telomerase-positive cells showed decreased SI and increased apparent diffusion coefficient (ADC) in DWI, while hTERT-AQP1-pretransduced telomerase-negative cells showed no obvious SI and ADC change. Correspondingly, hTERT-AQP1-transduced telomerase-positive tumors and CMV-AQP1-transduced telomerase-positive and -negative tumors showed decreased DWI SI and increased ADC, while hTERT-AQP1-transduced telomerase-negative tumor had no SI and ADC changes. After intratumoral or intravenous injection, CMV-AQP1 could upregulate AQP1 expression and induce DWI SI and ADC alteration in both telomerase-positive and -negative tumors, while hTERT-AQP1 worked in telomerase-positive tumors specifically. Cancers can be specifically visualized based on the DWI signal alteration which triggered by hTERT-AQP1 lentivirus system that combined AQP1 gene and hTERT promoter.

Abstract 1122‐000190: Persistent DWI Signal for 18 Months in Ischemic Stroke Patient with Carotid Web

Introduction : Diagnostic tools for acute ischemic infarcts include the use of DWI sequence on MRI to identify acute infarcts is especially useful since lesions can become hyperintense on this sequence very rapidly (Albers 1998). Over the next 15 days, DWI hyperintensity slowly decreases back to isointense. In some patients, however, there is persistent DWI hyperintensity past 1 month. There are theories that these persistent areas exhibit delayed onset infarct, prolonged ischemia, or perhaps different repair processes (Rivers, et al 2006). To this day, all DWI signals have been known to resolve within a few months even for persistent hyperintensities (Rivers, et al 2006). Carotid webs are a rare form of fibromuscular dysplasia that protrudes from the intimal tissues of carotid arteries. They are shelf‐like projections that grow into the lumen and disrupt normal blood flow (Zhang, et al 2018). These outgrowths are theorized to lead to ischemic strokes due to flow stasis and subsequent embolization of clots that form (Zhang, et al 2018). There is no consensus on the best management of carotid webs, and secondary prevention of recurrent strokes range from medical management to carotid stenting. Methods : This is a case report, and information for the patient was gathered through review of medical records on the EMR. Results : We present a case of ischemic stroke in the right basal ganglia/corona radiata, who presented with left sided weakness. The patient was found to have prediabetes, HTN, and HLD. However, she had recurrence of her symptoms over the next 18 months (figure 1). Repeat MRIs showed persistent DWI hyperintensity that slowly decreased in size and signal intensity over this period but in the same area as the initial infarct. The rest of the work up was only significant for a carotid web in the right internal carotid artery identified on conventional angiography. Ultimately she was managed with medical therapy including aspirin, statin, and antihypertensives. Conclusions : It is unclear whether the carotid web is associated with persistent DWI for such an extended time frame. There is very little research that explores the pathophysiology of ischemic strokes from carotid webs. In addition, there is even less information about the physiology of an evolving infarct that shows persistent DWI signals for such an extended time frame. Further studies that look into carotid webs may help us understand the best long term management in such patients. Future studies that explore the physiology of ischemic strokes that show such persistent DWI signals may elucidate and perhaps expand upon current management options and possibly identify new areas for intervention.

Clinical utility of arterial spin labeling perfusion images in the emergency department for the work-up of stroke-like symptoms.

To assess the utility of ASL in evaluating patients presenting to the ED with stroke-like symptoms. ASL and DWI images from 526 consecutive patients presenting to the ED with acute stroke symptoms were retrospectively reviewed. DWI images were evaluated for volume of restricted diffusion using ABC/2. ASL maps were evaluated for decreased, normal, or increased signal. The volume of decreased ASL signal was calculated using the same ABC/2 technique. The volume of decreased ASL signal was correlated with the volume of DWI signal abnormality to identify cases of mismatch (DWI:ASL ratio > 1.8) and to correlate this mismatch with infarct growth on imaging follow-up. NIHSS, length of hospital stay, mRS, and future admission for acute stroke-like symptoms were recorded. Correlations between ASL abnormalities and clinical parameters were evaluated using a two-tailed t-test. Of the 526 patients presenting with acute stroke symptoms, 136 patients had an abnormal ASL scan and 388 patients had a normal ASL scan. Of the 136 patients with abnormal ASL, 84 patients had low ASL signal with 79 of these being related to acute infarcts. Elevated ASL signal was seen in 52 patients, of which 30 of these patients had reperfusion hyperemia related to acute infarctions. ASL had a negative predictive value of 94% for evaluating patients with acute ischemic stroke. A subset of patients with abnormal ASL scans with a discharge diagnosis of acute infarction were found to have an ASL:DWI mismatch (ratio > 1.8) and demonstrated significant lesion growth on follow-up imaging (57%). This included some patients who exhibited low ASL signal before development of diffusion restriction (infarction). In patients presenting to the ED with acute stroke symptoms, ASL provides information not available with DWI alone. The NPV of ASL for evaluating patients with acute ischemia was 94%.

The relationship between diffusion heterogeneity and microstructural changes in high-grade gliomas using Monte Carlo simulations

PurposeDiffusion-weighted imaging (DWI) may aid accurate tumor grading. Decreased diffusivity and increased diffusion heterogeneity measures have been observed in high-grade gliomas using the non-monoexponential models for DWI. However, DWI measures concerning tissue characteristics in terms of pathophysiological and structural changes are yet to be established. Thus, this study aims to investigate the relationship between the diffusion measurements and microstructural changes in the presence of high-grade gliomas using a three-dimensional Monte Carlo simulation with systematic changes of microstructural parameters. MethodsWater diffusion was simulated in a microenvironment along with changes associated with the presence of high-grade gliomas, including increases in cell density, nuclear volume, extracellular volume (VFex), and extracellular tortuosity (λex), and changes in membrane permeability (Pmem). DWI signals were simulated using a pulsed gradient spin-echo sequence. The sequence parameters, including the maximum gradient strength and diffusion time, were set to be comparable to those of clinical scanners and advanced human MRI systems. The DWI signals were fitted using the gamma distribution and diffusional kurtosis models with b-values up to 6000 and 2500 s/mm2, respectively. ResultsThe diffusivity measures (apparent diffusion coefficients (ADC), Dgamma of the gamma distribution model and Dapp of the diffusional kurtosis model) decreased with increases in cell density and λex, and a decrease in Pmem. These diffusivity measures increased with increases in nuclear volume and VFex. The diffusion heterogeneity measures (σgamma of the gamma distribution model and Kapp of the diffusional kurtosis model) increased with increases in cell density or nuclear volume at the low Pmem, and a decrease in Pmem. Increased σgamma was also associated with an increase in VFex. ConclusionAmong simulated microstructural changes, only increases in cell density at low Pmem or decreases in Pmem corresponded to both the decreased diffusivity and increased diffusion heterogeneity measures. The results suggest that increases in cell density at low Pmem or decreases in Pmem may be associated with the diffusion changes observed in high-grade gliomas.

Construction of a novel radiomics nomogram for the prediction of aggressive intrasegmental recurrence of HCC after radiofrequency ablation

ObjectivesTo construct a precise prediction model of preoperative magnetic resonance imaging (MRI)-based nomogram for aggressive intrasegmental recurrence (AIR) of hepatocellular carcinoma (HCC) patients treated with radiofrequency ablation (RFA). MethodsAmong 891 patients with HCC treated by RFA, 22 patients with AIR and 36 patients without AIR (non-AIR) were finally enrolled in our study, and each patient was followed up for more than 6 months to determine the occurrence of AIR. The laboratory indicators and MRI features were compared and assessed. Preoperative contrast-enhanced T1-weighted images (CE-T1WI) were used for radiomics analysis. The selected clinical indicators and texture features were finally screened out to generate the novel prediction nomogram. ResultsTumor shape, ADC Value, DWI signal intensity and ΔSI were selected as the independent factors of AIR by univariate and multivariate logistic regression analysis. Meanwhile, two radiomics features were selected from 396 candidate features by LASSO (P < 0.05), which were further used to calculate the Rad-score. The selected clinical factors were further integrated with the Rad-score to construct the predictive model, and the AUCs were 0.941 (95% CI: 0.876–1.000) and 0.818 (95% CI: 0.576–1.000) in the training (15 AIR and 25 non-AIR) and validation cohorts (7 AIR and 11 non-AIR), respectively. The AIR predictive model was further converted into a novel radiomics nomogram, and decision curve analysis showed good agreement. ConclusionsThe predictive nomogram integrated with clinical factors and CE-T1WI -based radiomics signature could accurately predict the occurrence of AIR after RFA, which could greatly help individualized evaluation before treatment.

Ultrahigh-b diffusion-weighted imaging for quantitative evaluation of myelination in shiverer mouse spinal cord.

To perform a quantitative evaluation of myelination on WT and myelin-deficient (shiverer) mouse spinal cords using ultrahigh-b diffusion-weighted imaging (UHb-DWI). UHb-DWI of ex vivo on spinal cord specimens of two shiverer (C3HeB/FeJ-shiverer, homozygous genotype for MbPshi ) and six WT (Black Six, C3HeB/FeJ) mice were acquired using 3D multishot diffusion-weighted stimulated-echo EPI, a homemade RF coil, and a small-bore 7T MRI system. Imaging was performed in transaxial plane with 75 × 75 μm2 in-plane resolution, 1-mm-slice thickness, and radial DWI using bmax = 42,890 s/mm2 . Histological evaluation was performed on upper thoracic sections using optical and transmission electron microscopy. Numerical Monte Carlo simulations (MCSs) of water diffusion were performed to facilitate interpretation of UHb-DWI signal-b curves. The white matter ultrahigh-b radial DWI (UHb-rDWI) signal-b curves of WT mouse cords behaved biexponentially with high-b diffusion coefficient DH < 0.020 × 10-3 mm2 /s. However, as expected with less myelination, the signal-b of shiverer mouse cords behaved monoexponentially with significantly greater DH = 0.162 × 10-3 , 0.142 × 10-3 , and 0.164 × 10-3 mm2 /s at anterodorsal, posterodorsal, and lateral columns, respectively. The axial DWI signals of all mouse cords behaved monoexponentially with D = (0.718-1.124) × 10-3 mm2 /s. MCS suggests that these elevated DH are mainly induced by increased water exchange at the myelin sheath. Microscopic results were consistent with the UHb-rDWI findings. UHb-DWI provides quantitative differences in myelination of spinal cords from myelin-deficit shiverer and WT mice. UHb-DWI may become a powerful tool to evaluate myelination in demyelinating disease models that may translate to human diseases, including multiple sclerosis.

Apparent diffusion coefficient agreement and reliability using different region of interest methods for the evaluation of head and neck cancer post chemo-radiotherapy.

Objectives:Post chemoradiotherapy (CRT) interval changes in apparent diffusion coefficient (ADC) have prognostic value in head and neck squamous cell cancer (HNSCC). The impact of using different region of interest (ROI) methods on interobserver agreement and their ability to reliably detect the changes in the ADC values was assessed.Methods:Following ethical approval, 25 patients (mean age 59.5 years, 21 male) with stage 3–4 HNSCC undergoing CRT were recruited for this prospective cohort study. Diffusion weighted MRI (DW-MRI) was performed pre-treatment and at 6 and 12 weeks following CRT. Two radiologists independently delineated ROIs using whole volume (ROIv), largest area (ROIa) or representative area (ROIr) methods at primary tumour (n = 22) and largest nodal (n = 24) locations and recorded the ADCmean. When no clear focus of increased DWI signal was evident at follow-up, a standardised ROI was placed (non-measurable or NM). Bland-Altman plots and interclass correlation coefficient (ICC) were assessed. Paired t-tests evaluated interval changes in pre- and post-treatment ADCmean at each location, which were compared to the smallest detectable difference (SDD).Results:Excellent agreement was obtained for all ROI methods at pre-treatment (ICC 0.94–0.98) and 6-week post-treatment (ICC 0.94–0.98). At 12-week post-treatment, agreement was excellent (ICC 0.91–0.94) apart from ROIr (ICC 0.86) and the NM nodal disease (ICC 0.87). There were significant interval increases in ADCmean between pre-treatment and post-treatment studies, which were greater than the SDD for all ROIs.Conclusions:ADCmean values can be reproducibly obtained in HNSCC using the different ROI techniques on pre- and post-CRT MRI, and this reliably detects the interval changes.

Parsimonious modeling of skeletal muscle perfusion: Connecting the stretched exponential and fractional Fickian diffusion.

To develop an anomalous (non-Gaussian) diffusion model for characterizing skeletal muscle perfusion using multi-b-value DWI. Fick's first law was extended for describing tissue perfusion as anomalous superdiffusion, which is non-Gaussian diffusion exhibiting greater particle spread than that of the Gaussian case. This was accomplished using a space-fractional derivative that gives rise to a power-law relationship between mean squared displacement and time, and produces a stretched exponential signal decay as a function of b-value. Numerical simulations were used to estimate parameter errors under in vivo conditions, and examine the effect of limited SNR and residual fat signal. Stretched exponential DWI parameters, α and , were measured in thigh muscles of 4 healthy volunteers at rest and following in-magnet exercise. These parameters were related to a stable distribution of jump-length probabilities and used to estimate microvascular volume fractions. Numerical simulations showed low dispersion in parameter estimates within 1.5% and 1%, and bias errors within 3% and 10%, for α and , respectively. Superdiffusion was observed in resting muscle, and to a greater degree following exercise. Resting microvascular volume fraction was between 0.0067 and 0.0139 and increased between 2.2-fold and 4.7-fold following exercise. This model captures superdiffusive molecular motions consistent with perfusion, using a parsimonious representation of the DWI signal, providing approximations of microvascular volume fraction comparable with histological estimates. This signal model demonstrates low parameter-estimation errors, and therefore holds potential for a wide range of applications in skeletal muscle and elsewhere in the body.

MRI Posttreatment Surveillance for Head and Neck Squamous Cell Carcinoma: Proposed MR NI-RADS Criteria.

The current Neck Imaging Reporting and Data System (NI-RADS) criteria were designed for contrast-enhanced CT with or without PET. Prior studies have revealed the capability of DWI and T2 signal intensity in distinguishing locoregional tumor residual and recurrence from posttreatment benign findings in head and neck cancers. We aimed to propose MR imaging NI-RADS criteria by adding diffusion criteria and T2 signal intensity to the American College of Radiology NI-RADS template. This retrospective study included 69 patients with head and neck squamous cell carcinoma (HNSCC) who underwent posttreatment contrast-enhanced MRI imaging surveillance using a 1.5T scanner. The scans were interpreted by 2 neuroradiologists. Image analysis assessed the primary tumor site using the current American College of Radiology NI-RADS morphologic lexicon (mainly designed for contrast-enhanced CT with or without PET). NI-RADS rescoring was then performed based on our proposed criteria using T2 signal and diffusion features. The reference standard was a defined set of criteria, including clinical and imaging follow-up and pathologic assessment. Imaging assessment of treated HNSCC at the primary tumor site using T2 signal intensity and diffusion features as modifying rules to NI-RADS showed higher sensitivity, specificity, positive predictive value, negative predictive value, and accuracy (92.3%, 90.7%, 85.7%, 95.1%, and 91.3%, respectively) compared with the current NI-RADS lexicon alone (84.6%, 81.4%, 73.3%, 89.8%, and 82.6%, respectively). The addition of diffusion features and T2 signal to the American College of Radiology NI-RADS criteria for the primary tumor site enhances the specificity, sensitivity, positive predictive value, negative predictive value, and NI-RADS accuracy.

Finite element simulations of hyperpolarized gas DWI in micro-CT meshes of acinar airways: validating the cylinder and stretched exponential models of lung microstructural length scales.

This work assesses the accuracy of the stretched exponential (SEM) and cylinder models of lung microstructural length scales that can be derived from hyperpolarized gas DWI. This was achieved by simulating 3 He and 129 Xe DWI signals within two micro-CT-derived realistic acinar airspace meshes that represent healthy and idiopathic pulmonary fibrosis lungs. The healthy and idiopathic pulmonary fibrosis acinar airway meshes were derived from segmentations of 3D micro-CT images of excised human lungs and meshed for finite element simulations of the Bloch-Torrey equations. 3 He and 129 Xe multiple b value DWI experiments across a range of diffusion times (3 He Δ = 1.6 ms; 129 Xe Δ = 5 to 20 ms) were simulated in each mesh. Global SEM mean diffusive length scale and cylinder model mean chord length value was derived from each finite element simulation and compared against each mesh's mean linear intercept length, calculated from intercept length measurements within micro-CT segmentation masks. The SEM-derived mean diffusive length scale was within ±10% of the mean linear intercept length for simulations with both 3 He (Δ = 1.6 ms) and 129 Xe (Δ = 7 to 13 ms) in the healthy mesh, and with 129 Xe (Δ = 13 to 20 ms) for the idiopathic pulmonary fibrosis mesh, whereas for the cylinder model-derived mean chord length the closest agreement with mean linear intercept length (11.7% and 22.6% difference) was at 129 Xe Δ = 20 ms for both healthy and IPF meshes, respectively. This work validates the use of the SEM for accurate estimation of acinar dimensions and indicates that the SEM is relatively robust across a range of experimental conditions and acinar length scales.

Correlation between contrast enhanced plaques and plaque diffusion restriction and their signal intensities in FLAIR images in patients who admitted with acute symptoms of multiple sclerosis

IntroductionOne of the most common demyelinating disorders is Multiple Sclerosis (MS), which can lead to extensive disability in patients. Appearance of active lesions can be an important sign of disease development. The correlation between the restriction of DWI signal, contrast-enhancement, and demyelinated plaque's signals were evaluated in this study. Material and method34 MS patients with 1043 MS-plaques who had acute attacks took part in this study. Three MRI pulse-sequences, FLAIR, DWI, and post-contrast enhanced T1 weighted, were compared. Using the signal intensity of MS-lesions and normal brain tissue in FLAIR images, lesion/noise ratio (LNR) and lesion/white-matter ratio (LWR) were calculated. Sensitivity and specificity of LNR and LWR were estimated to determine a cut off value. Results7.86% of MS-plaques were enhanced in T1 contrast-enhanced MRI. 2.4% showed DWI restriction. 0.77% showed both diffusion-restriction and T1 contrast-enhancement, 1.63% indicated diffusion-restriction but no contrast-enhancement and 7.09% showed contrast-enhancement but no diffusion-restriction. Among diffusion-restricted plaques, 32% were enhanced in T1-weighted post-contrast enhanced images and it should be noted that diffusion-restriction was seen in 9.76% of enhanced plaques. The sensitivity and specificity of the DWI restriction and its effectiveness in detecting active-plaques were calculated as 12.31% and 98.26%, respectively. The accuracy of this method in detecting the active MS-plaques estimated as 92.91%. The cut-off value for LWR and LNR was between 0.9–1 and 24–28. ConclusionBy calculating LNR and LWR, the FLAIR images can be evaluated to detect new MS-plaques. LWR had higher sensitivity and specificity in comparison to LNR so it is a better index in the detection of active-plaques. Although post contrast T1 is the gold standard for evaluating active plaques, in the case of a contraindication to gadolinium, DWI can offer supplemental information on the diffusion restriction of MS plaques in a non-contrast protocol.

Effect of MRI Images Based on Semi-Automatic Volume Segmentation in Patients with Acute Ischemic Stroke

Objective: To study the MRI and CT characteristics of different periods of acute ischemic stroke and evaluate its diagnostic value by using semi-automatic mention segmentation method. Methods: CT, conventional MRI and DWI were performed in 64 patients with acute ischemic stroke. The average ADC value and average relative ADC (rADC) value of infarct lesions were measured and statistically analyzed. Results: There were no significant differences in CT, conventional MRI, and DWI signal characteristics between 1 and 7 days after the onset of acute ischemic stroke. The average ADC value and the average rADC value decreased, but the average rADC in the infarct area increased with time. The rADC value was statistically significant with the onset of 1d, 2d, 3d, and 4d (P &lt; 0.05), but not statistically significant with the onset of 5d and 6d (P &gt; 0.05). Conclusion: In the image processing method of semi-automatic segmentation method, the characteristics of CT, conventional MRI, and DWI signals combined with the evolution of rADC values over time can help to judge the pathophysiological changes of acute ischemic stroke, which is ischemic. Stroke staging and treatment guidance are provided.

Diffusion-weighted MRI and FLAIR sequence for differentiation of hydatid cysts and simple cysts in the liver

PurposeThe contribution of DWI and FLAIR to the differential diagnosis of type 1, 2, and 3 hydatid cysts and simple liver cysts was investigated according to the Gharbi classification. This study is the first report using FLAIR sequence for the differential diagnosis of liver hydatid cysts in this regard. MethodsA total of 82 hydatid cysts and 40 simple cysts were scanned with DWI (in b600-b1000 values) and FLAIR sequence. In 64 patients included in the study, a total of 122 cystic lesions were diagnosed histopathologically or during follow-up. FLAIR and DWI signal characteristics were evaluated, and ADC values were calculated. ResultsThe mean ADC value of hydatid cysts on DWI (b600) was 3.07 ± 0.41 × 10−3 s/mm2, while it was 3.91 ± 0.51 × 10−3 s/mm2 for simple cysts and the difference was statistically significant (p < 0.05). On b1000 DWI, the mean ADC values of hydatid and simple cysts were 2.99 ± 0.38 × 10−3 s/mm2 and 3.43 ± 0:29 × 10−3 s/mm2, respectively (p < 0.05). The qualitative evaluation of the signal intensity on b600−1000 DWI demonstrated the difference between the simple and hydatid cyst groups (p < 0.05). Type 2 hydatid cysts alone were distinguished from type 2–3 hydatid and simple cysts by FLAIR (p < 0.05). ConclusionsADC values can distinguish between hydatid cyst and simple cyst. FLAIR contributes to the differentiation of type 2 hydatid and simple cysts.

Validation of combined use of DWI and percentage signal recovery-optimized protocol of DSC-MRI in differentiation of high-grade glioma, metastasis, and lymphoma.

With conventional MRI, it is often difficult to effectively differentiate between contrast-enhancing brain tumors, including primary central nervous system lymphoma (PCNSL), high-grade glioma (HGG), and metastasis. This study aimed to assess the discrimination ability of the parameters obtained from DWI and the percentage signal recovery- (PSR-) optimized protocol of DSC-MRI between these three tumor types at an initial step. DSC-MRI using a PSR-optimized protocol (TR/TE = 1500/30 ms, flip angle = 90°, no preload) and DWI of 99 solitary enhancing tumors (60 HGGs, 24 metastases, 15 PCNSLs) were retrospectively assessed before treatment. rCBV, PSR, ADC in the tumor core and rCBV, and ADC in peritumoral edema were measured. The differences were evaluated using one-way ANOVA, and the diagnostic performance was evaluated using ROC curve analysis. PSR in the tumor core showed the best discriminating performance in differentiating these three tumor types with AUC values of 0.979 for PCNSL vs. others and 0.947 for HGG vs. metastasis. The ADC was only helpful in the tumor core and distinguishing PCNSLs from others (AUC = 0.897). Different from CBV-optimized protocols (preload, intermediate FA), PSR derived from the PSR-optimized protocol seems to be the most important parameter in the differentiation of HGGs, metastases, and PCNSLs at initial diagnosis. This property makes PSR remarkable and carries the need for comprehensive DSC-MRI protocols, which provides PSR sensitivity and CBV accuracy together, such as the preload use of the PSR-optimized protocol before the CBV-optimized protocol.

A probable role of copper in the comorbidity in Wilson\u2019s and Creutzfeldt-Jakob\u2019s Diseases: a case report

BackgroundTo the best of our knowledgedd, there is currently no case in the literature reporting the comorbidity of Wilson’s and Creutzfeldt-Jakob disease (CJD), linked through copper.Case presentationA 44-year-old male with a history of inherited Wilson’s disease (hepatolenticular degeneration), which manifested as mild liver injury and psychiatric symptoms, was admitted to our department due to speech and cognitive disturbances. Upon his admission, he had motor aphasia as well as psychomotor retardation with an otherwise normal neurological examination. Laboratory tests, including liver enzymes, copper and serum ammonia were all within normal range. The brain MRI showed increased T2 signal in the caudate nuclei, attributed to copper deposition in the context of Wilson’s disease. In the electroencephalogram, periodic sharp discharges were eminent, initially unilateral and then generalized. The positive 14–3-3 protein in the cerebrospinal fluid (CSF) and the new brain MRI, that demonstrated elevated DWI signal not only in the basal ganglia but also in parts of the cerebral cortex (cortical ribbon sign), all supportive of a possible CJD diagnosis. The detection of PrPSc in the patient’s CSF, using the RT-QuIC method, which has a 99.4–100% specificity for CJD, made the diagnosis of CJD highly probable.ConclusionThis is the first report of Wilson’s and Creutzfeldt-Jakob diseases co-morbidity in the literature, which could evoke a possible role of copper in the pathogenesis of CJD.

Anoxic Brain Injury Detection with the Normalized Diffusion to ASL Perfusion Ratio: Implications for Blood-Brain Barrier Injury and Permeability.

Anoxic brain injury is a result of prolonged hypoxia. We sought to describe the nonquantitative arterial spin-labeling perfusion imaging patterns of anoxic brain injury, characterize the relationship of arterial spin-labeling and DWI, and evaluate the normalized diffusion-to-perfusion ratio to differentiate patients with anoxic brain injury from healthy controls. We identified all patients diagnosed with anoxic brain injuries from 2002 to 2019. Twelve ROIs were drawn on arterial spin-labeling with coordinate-matched ROIs identified on DWI. Linear regression analysis was performed to examine the relationship between arterial spin-labeling perfusion and diffusion signal. Normalized diffusion-to-perfusion maps were generated using a custom-built algorithm. Thirty-five patients with anoxic brain injuries and 34 healthy controls were identified. Linear regression analysis demonstrated a significant positive correlation between arterial spin-labeling and DWI signal. By means of a combinatory cutoff of slope of >0 and R2 of > 0.78, linear regression using arterial spin-labeling and DWI showed a sensitivity of 0.86 (95% CI, 0.71-0.94) and specificity of 0.82 (95% CI, 0.66-0.92) for anoxic brain injuries. A normalized diffusion-to-perfusion color map demonstrated heterogeneous ratios throughout the brain in healthy controls and homogeneous ratios in patients with anoxic brain injuries. In anoxic brain injuries, a homogeneously positive correlation between qualitative perfusion and DWI signal was identified so that areas of increased diffusion signal showed increased ASL signal. By exploiting this relationship, the normalized diffusion-to-perfusion ratio color map may be a valuable imaging biomarker for diagnosing anoxic brain injury and potentially assessing BBB integrity.

Ultrasound and MRI features of malignant fibrous histiocytoma of soft tissue

To investigate ultrasound and MRI features of malignant fibrous histiocytoma (MFH) of soft tissue. Ultrasound, MRI images and pathological data of 12 patients with malignant fibrous histiocytoma in soft tissue confirmed by operation and pathology were analyzed from January 2012 to August 2018, inlcuding 7 males and 5 females, aged from 36 to 69 years old with an average age of 53 years old; the courses of disease ranged from 4 to 49 months with an average of 28 months. Clinical manifestations were soft tissue masses and pain in the affected limbs. Ultrasound, MRI and contrast-enhanced examination were performed before operation. The lesions, morphology, echo/signal characteristics, color flow signals and enhancement features were observed and compared with pathology. In 12 patients with MFH, 9 patients were primary lesions and 3 patients were recurrent lesions after operation. There were 7 cases of bilateral thighs, 2 cases of calves, 1 case of upper arm, 1 case of buttocks and 1 case of posterior peritoneum. The size ranged from 5.1 to 17.1 cm with an average of 8.7 cm. Ultrasound feature showed lobulated or agglomerate, and focused on low echo; 5 cases had capsule and with clear border; 7 cases were unclear boundary with surrounding tissues; and 6 cases with irregular echo-free. The blood flow signals were around the CDFI, and the internal blood flow signals were different. MRI feature showed lobulated, agglomerate or irregular shape, T1WI showed slightly lower signal or equal signal, T2WI showed high signal and DWI signal increased. Six patients manifested mixed signal inside, 7 patients manifested low signal separation inside, 5 patients with false envelope, and 9 patients manifested infiltration and growth with peripheral edema. T1WI showed uneven strengthening after enhancement. Immunohistochemical expression of Vim, CD68 were positive. The age, location and imaging features of soft tissue MFH are characteristic. The diagnosis of MFH should be considered when irregular mass occurred in soft tissues of limbs at middle-aged and old people. Echo and signal are homogeneous or mixed. Separation, necrosis and cystic degeneration could be seen in the mass. When the blood flow signals are abundant and solid components are obviously enhanced, the diagnosis of MFH should be considered.

Whole-body bone marrow DWI correlates with age, anemia, and hematopoietic activity

PurposeTo identify the predictors of bone-marrow DWI signals from anthropometric, complete blood count (CBC), and C-reactive protein (CRP), and to evaluate the association with fat-content in patients. MethodThis retrospective study was approved by the institutional review board. A total of 113 consecutive tumor patients underwent whole-body PET/MRI. Apparent diffusion coefficient (ADC) and proton density fat fraction (PDFF) were measured and averaged in lumbar vertebrae (L3-5) and bilateral ilia. Due to respiratory motion, ribs were evaluated by 3-point visual scoring on DWI with b = 800 (1: invisible, 2: partially visible, 3: fully visible). The relationships between ADC/visual scores and anthropometric, CBC, CRP, and PDFF were examined. In females, the age-dependency was evaluated. ResultsMulti-regression analyses identified age as the strongest predictor of lumbar ADC (standardized coefficient: β = 0.45), followed by red cell distribution width (RDW) (β = −0.24), while age was the strongest predictor of iliac ADC (β = 0.43), followed by hemoglobin (Hb) (β = 0.22). RDW was the strongest predictor (β = 0.47) for rib visual score and age was the second (β = -0.39). ADC showed significant positive correlations with PDFF at L3-5 and ilium. Lumbar ADC showed a decreasing trend during middle age in females. ConclusionsAge, anemia (lower Hb), and increased hematopoietic activity (higher RDW) are the predominant predictors of ADC and the visibility of red marrow on DWI. Fat-suppression methods and bone-marrow physiology in middle-aged females may have affected the measured correlations between ADC and PDFF inconsistent with previous studies.