3D Texture Analysis of MRI Relaxation Time Maps for Assessment of Repair Cartilage with Treatment of Allogeneic Human Adipose-Derived Mesenchymal Progenitor Cells

Background: We used textural analysis matrix to examine the spatial distribution of pixel values and detect the compositional variation of repair cartilage with treatment of allogeneic human adipose-derived mesenchymal progenitor cells (haMPCs). Methods: Eighteen patients were divided randomly into three groups with intra-articular injections of haMPCs: the low-dose (1.0×107 cells), mid-dose (2.0×107), and high-dose (5.0×107) group with six patients each. 3D texture analyses based on gray level run-length matrix (GLRLM) of the segmented ROIs on MRI relaxation time maps including T1rho, T2, T2* and R2*. Five GLRLM parameters were analyzed, including run length non-uniformity (RLNonUni), grey level non-uniformity (GLevNonU), long run emphasis (LngREmph), short run emphasis (ShrtREmp) and fraction of image in runs (Fraction). We used the difference before and after treatment (D values) as the object to avoid errors caused by individual differences. Two-tailed Pearson linear correlation analysis was used to investigate correlations between texture parameters and the WOMAC scores. Results: The heterogeneity of spatial distribution of MRI relaxation time mapping pixels from three groups was decreased to varying degrees at 48 weeks after intra-articular injection of haMPCs. Spatial distribution of cartilage relaxation time maps pixels were uneven and layered, especially in T2 maps. Compared with base time, there were significant differences among three dose groups in GLRLM features for T1rho map including RLNonUni, GLevNonU, LngREmph, for T2 map including LngREmph, GLevNonU, ShrtREmp, for T2* map including RLNonUni, GLevNonU, and for R2* map including RLNonUni, GLevNonU. WOMAC pain scores were associated with RLNonUni of T1rho map, GLevNonU of T2 map, LngREmph of T2* map, LngREmph of R2* map and Fraction of T1rho map, whereas no significant correlations in other measurements.Conclusions: MRI texture analysis of cartilage may allow detection of the compositional variation of repair cartilage with treatment of allogeneic haMPCs. This has potential applications in understanding mechanism of stem cells repairing cartilage and assessing response to treatment.Trial registration: Clinicaltrials, NCT02641860. Registered 3 December 2015.https://www.clinicaltrials.gov/ct2/show/NCT02641860

LNMR Study on Microstructure Characteristics and Pore Size Distribution of High-Rank Coals with Different Bedding

In order to study the pore structure characteristics of high-rank coals with different bedding, NMR experiments were carried out for high-rank coals with different bedding angles (0°, 30°, 45°, 60°, and 90°). The results show that the distribution of T2 map of high-rank coal with different bedding is similar to some extent, showing a double peak or triple peak distribution, and the first peak accounts for more than 97% of the total, indicating that small holes are developed in high-rank coal with different bedding, while macropores are not developed. The influence of bedding angle on the fracture proportion is less than 0.3%. Compared with the fracture proportion, the effect of bedding angle on the proportion of microhole, medium hole, and large hole is greater and presents a certain rule. There are certain differences in T2 cutoff value (T2C) of high-rank coal with different bedding. The relationship between bedding angle and T2C conforms to exponential function, and the correlation degree R2 is 0.839. The research results provide a theoretical basis for gas extraction and utilization and prevention of gas disaster in coal mines in China.

The Value of Combined Application of Oxycodone Hydrochloride Injection and Dexmedetomidine in Anesthesia for LC for Patients with Gallbladder Lesions

Objective. To analyze the effect of combined application of oxycodone hydrochloride injection and dexmedetomidine in anesthesia for laparoscopic cholecystectomy (LC) for patients with gallbladder lesions. Method. 93 patients with gallbladder lesions in our hospital were divided into 2 groups by the random number table method. 46 patients in the control group applied oxycodone hydrochloride injection in anesthesia, and 47 patients in the observation group applied oxycodone hydrochloride injection combined with dexmedetomidine in anesthesia. Result. The T1 and T2 MAP levels in the observation group were lower than those in the control group ( P < 0.05 ), and the difference between T3 and the control group was not significantly significant ( P > 0.05 ). The T1 to T3 HR level in the observation group were lower than those in the control group ( P < 0.05 ). The rate of excessive sedation (10.64%) and sedation inefficiency (12.77%) in the observation group was lower than that in the control group (28.26% and 30.43%), and the rate of satisfactory sedation (76.60%) was higher than that in the control group (41.30%) ( P < 0.05 ). The postoperative awakening, tracheal tube removal, and first anal venting time were shorter in the observation group than in the control group ( P < 0.05 ). The WHO scores of incisional pain at 6, 12, 24, and 48 hours after the operation were lower in the observation group than in the control group ( P < 0.05 ). The T2 SOD level in the observation group was higher than that in the control group, and the ROS and MDA levels were lower than those in the control group ( P < 0.05 ). The incidence of side effects of anesthetic in the observation group was 17.02%, which was not statistically different from the control group of 13.04% ( P > 0.05 ). Conclusion. The combined application of oxycodone hydrochloride injection and dexmedetomidine in anesthesia for LC for patients with gallbladder lesions can achieve better sedation and analgesia effect, accelerate postoperative awakening and recovery, and control oxidative stress and fluctuations in signs, without increasing anesthesia-related side effects.

Fat-suppressed T2 mapping of human knee femoral articular cartilage: comparison with conventional T2 mapping

Background There is paucity of studies applying fat suppressed (FS) technique to T2 mapping to overcome chemical shift artifacts. The purpose of the study is to difference between FS T2 and conventional T2 mapping and reproducibility of FS T2 mapping in the femoral articular cartilage. Methods Eighteen patients who had normal-looking femoral cartilage and underwent knee MRI with conventional T2 and FS T2 mapping were included. T2 values of each mapping were measured by two readers independently from nine regions in the medial femoral condyle (MFC) and lateral femoral condyle (LFC). Each anatomical region was divided by lines at ± 10°, 30°, 50°, 70°, 90°, and 110°. Comparisons of T2 values between conventional and FS T2 mapping were statistically analyzed. The T2 values between FS and conventional T2 mapping in the anterior, central and posterior femoral condyles were compared. Results The overall femoral condyle T2 values from the FS T2 map were significantly lower than those from the conventional T2 map (48.5ms vs. 51.0ms, p < 0.001). The differences in the T2 values between the two maps were significantly different among the three divisions of the LFC (p = 0.009) and MFC (p = 0.031). The intra-class correlation coefficients indicated higher agreement in the FS T2 map than in the conventional T2 map (0.943 vs. 0.872). Conclusions The T2 values of knee femoral cartilage are significantly lower on FS T2 mapping than on conventional T2 mapping. FS T2 mapping is a more reproducible method for evaluating knee femoral cartilage.

Impact of rescanning and repositioning on radiomic features employing a multi-object phantom in magnetic resonance imaging

Our purpose was to analyze the robustness and reproducibility of magnetic resonance imaging (MRI) radiomic features. We constructed a multi-object fruit phantom to perform MRI acquisition as scan-rescan using a 3 Tesla MRI scanner. We applied T2-weighted (T2w) half-Fourier acquisition single-shot turbo spin-echo (HASTE), T2w turbo spin-echo (TSE), T2w fluid-attenuated inversion recovery (FLAIR), T2 map and T1-weighted (T1w) TSE. Images were resampled to isotropic voxels. Fruits were segmented. The workflow was repeated by a second reader and the first reader after a pause of one month. We applied PyRadiomics to extract 107 radiomic features per fruit and sequence from seven feature classes. We calculated concordance correlation coefficients (CCC) and dynamic range (DR) to obtain measurements of feature robustness. Intraclass correlation coefficient (ICC) was calculated to assess intra- and inter-observer reproducibility. We calculated Gini scores to test the pairwise discriminative power specific for the features and MRI sequences. We depict Bland Altmann plots of features with top discriminative power (Mann–Whitney U test). Shape features were the most robust feature class. T2 map was the most robust imaging technique (robust features (rf), n = 84). HASTE sequence led to the least amount of rf (n = 20). Intra-observer ICC was excellent (≥ 0.75) for nearly all features (max–min; 99.1–97.2%). Deterioration of ICC values was seen in the inter-observer analyses (max–min; 88.7–81.1%). Complete robustness across all sequences was found for 8 features. Shape features and T2 map yielded the highest pairwise discriminative performance. Radiomics validity depends on the MRI sequence and feature class. T2 map seems to be the most promising imaging technique with the highest feature robustness, high intra-/inter-observer reproducibility and most promising discriminative power.

Quantitative MRI Reveals Grey Matter Abnormalities in Children With Drug-Naïve Attention-Deficit/Hyperactivity Disorder

Purpose To investigate the quantitative profiles of brain GM in pediatric drug-naïve ADHD patients using Synthetic magnetic resonance imaging (SyMRI). Method and Materials: A total of 37 drug-naïve pediatric ADHD and 27 age- and gender-matched healthy controls (HC) were enrolled in this study. Each subject underwent both SyMRI and conventional 3D T1-FSPGR scans. Quantitative parameters, T1 and T2 maps, were extracted from the SyMRI data. Between-group quantitative maps were compared using a general linear model analysis. Pearson correlation analysis was conducted to assess the association between significantly altered MR indices and clinical measurements in ADHD. Results Compared with the HC group, altered T1 and T2 relaxometry times in the ADHD group were mainly distributed in GM regions of the cerebellum, attention and execution control network, default mode network, and limbic areas. Moreover, the T1 value of the right cerebellum 8 was negatively correlated with the attention concentration level in ADHD (R = 0.1401, P = 0.0225). With regards to T2 map, the associations were observed between the attention level of ADHD patients and left fusiform gyrus (R = 0.2509, P = 0.0016), and right cerebellum crus2 (R = 0.1422, P = 0.0214). Conclusion Altered T1, T2 values found in specific regions of GM may reveal widespread micromorphology changes, i.e., brain iron deficiency, low myelin content, and enlarged vascular interstitial space in ADHD patients. Thus, T1, T2 values might be promising imaging markers for future ADHD studies.

Quantitative Multicomponent T2 Relaxation Showed Greater Sensitivity Than Flair Imaging to Detect Subtle Alterations at the Periphery of Lower Grade Gliomas

PurposeTo demonstrate that quantitative multicomponent T2 relaxation can be more sensitive than conventional FLAIR imaging for detecting cerebral tissue abnormalities.MethodsSix patients affected by lower-grade non-enhancing gliomas underwent T2 relaxation and FLAIR imaging before a radiation treatment by proton therapy (PT) and were examined at follow-up. The T2 decay signal obtained by a thirty-two-echo sequence was decomposed into three main components, attributing to each component a different T2 range: water trapped in the lipid bilayer membrane of myelin, intra/extracellular water and cerebrospinal fluid. The T2 quantitative map of the intra/extracellular water was compared with FLAIR images.ResultsBefore PT, in five patients a mismatch was observed between the intra/extracellular water T2 map and FLAIR images, with peri-tumoral areas of high T2 that typically extended outside the area of abnormal FLAIR hyper-intensity. Such mismatch regions evolved into two different types of patterns. The first type, observed in three patients, was a reduced extension of the abnormal regions on T2 map with respect to FLAIR images (T2 decrease pattern). The second type, observed in two patients, was the appearance of new areas of abnormal hyper-intensity on FLAIR images matching the anomalous T2 map extension (FLAIR increase pattern), that was considered as asymptomatic radiation induced damage.ConclusionOur preliminarily results suggest that quantitative T2 mapping of the intra/extracellular water component was more sensitive than conventional FLAIR imaging to subtle cerebral tissue abnormalities, deserving to be further investigated in future clinical studies.

The diagnostic value of T2 map, diffusion tensor imaging, and diffusion kurtosis imaging in differentiating dermatomyositis from muscular dystrophy

Background Dermatomyositis (DM) and muscular dystrophy are clinically difficult to differentiate. Purpose To confirm the feasibility and assess the accuracy of conventional magnetic resonance imaging (MRI), T2 map, diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI) in the differentiation of DM from muscular dystrophy. Material and Methods Forty-two patients with DM proven by diagnostic criteria were enrolled in the study along with 23 patients with muscular dystrophy. Conventional MR, T2 map, DTI, and DKI images were obtained in the thigh musculature for all patients. Intramuscular T2 value, apparent diffusion coefficient (ADC), fractional anisotropy (FA), mean diffusivity (MD), and mean kurtosis (MK) values were compared between the patients with DM and muscular dystrophy. Student’s t-tests and receiver operating characteristic (ROC) curve analyses were performed for all parameters. P values < 0.05 were considered statistically significant. Results The intramuscular T2, ADC, FA, MD, and MK values within muscles were statistically significantly different between the DM and muscular dystrophy groups ( P<0.01). The MK value was statistically significantly different between the groups in comparison with T2 and FA value. As a supplement to conventional MRI, the parameters of MD and MK differentiated DM and muscular dystrophy may be valuable. The optimal cut-off value of ADC and MD values (with respective AUC, sensitivity, and specificity) between DM and muscular dystrophy were 1.698 ×10−3mm2/s (0.723, 54.1%, and 78.1%) and 1.80 ×10−3mm2/s (61.9% and 70.2%), respectively. Conclusion Thigh muscle ADC and MD parameters may be useful in differentiating patients with DM from those with muscular dystrophy.

MR relaxometry-based analysis of brain hemorrhages: an experimental study on a rabbit model

Magnetic Resonance Relaxometry is a quantitative MRI-based technique able to estimate tissue relaxation times T1 and T2. This approach allows increasing the MRI diagnostic accuracy mostly in case of brain neoplasia or neurodegenerative disorders in human medicine. However, few reports are available on the application of this technique in the clinical field of veterinary medicine. For this reason, in this work, we developed a relaxometry based approach on experimentally induced brain hemorrhages on rabbits. Specifically, the methodology is based on a hierarchical clustering procedure driven by the T1 relaxometry signals from a set of regions of interest selected on the T2 map. The approach is multivariate since it combines both T1 and T2 information and allows the diagnosis at the subject level by comparing “suspected” pathological regions with healthy homologous ones within the same brain.To validate the proposed technique, the scanned brains underwent histopathological analyses to estimate the performance of the proposed classifier in terms of Receiver Operator Curve analyses. The results showed that, in terms of identification of the lesion and its contours, the proposed approach resulted accurate and outperformed the standard techniques based on T1w and T2w images. Finally, since the proposed protocol in terms of the adopted scanner, sequences, and analysis tools, is suitable for the clinical practice, it can be potentially validated through large-scale multi-center clinical studies.