MRI: Evaluating the Application of FOCUS-MUSE Diffusion-Weighted Imaging in the Pancreas in Comparison With FOCUS, MUSE, and Single-Shot DWIs.

BACKGROUND: Diffusion-weighted imaging (DWI) is a useful technique to detect pancreatic lesion. In DWIs, field-of-view optimized and constrained undistorted single-shot (FOCUS) can improve the spatial resolution and multiplexed sensitivity-encoding (MUSE) can gain a high signal-to-noise ratio (SNR). Based on the advantage of FOCUS and MUSE, a new DWI sequence-named FOCUS-MUSE DWI (FOCUS combined with MUSE)-was developed to delineate the pancreas. PURPOSE: To investigate the reliability of FOCUS-MUSE DWI compared to FOCUS, MUSE and single-shot (SS) DWI via the systematical evaluation of the apparent diffusion coefficient (ADC) measurements, SNR and image quality. STUDY TYPE: Prospective. SUBJECTS: A total of 33 healthy volunteers and 9 patients with pancreatic lesion. FIELD STRENGTH/SEQUENCE: A 3.0 T scanner. FOCUS-MUSE DWI, FOCUS DWI, MUSE DWI, SS DWI. ASSESSMENT: For volunteers, ADC and SNR were measured by two readers in the pancreatic head, body, and tail. For all subjects, the diagnostic image quality score was assessed by three other readers on above four DWIs. STATISTICAL TESTS: Paired-sample T-test, intraclass correlation (ICC), Bland-Altman method, Friedman test, Dunn-Bonferroni post hoc test and kappa coefficient. A significance level of 0.05 was used. RESULTS: FOCUS-MUSE DWI had the best intersession repeatability of ADC measurements (head: 59.53, body: 101.64, tail: 42.30) among the four DWIs, and also maintained the significantly highest SNR (reader 1 [head: 19.68 ± 3.23, body: 23.42 ± 5.00, tail: 28.85 ± 4.96], reader 2 [head: 19.93 ± 3.52, body: 23.02 ± 5.69, tail: 29.77 ± 6.33]) except for MUSE DWI. Furthermore, it significantly achieved better image quality in volunteers (median value: 4 score) and 9 patients (most in 4 score). DATA CONCLUSION: FOCUS-MUSE DWI improved the reliability of pancreatic images with the most stable ADC measurement, best image quality score and sufficient SNR among four DWIs. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Differentiating the clinical and computed tomography imaging features of mixed epithelial and stromal tumors of the kidney to establish a treatment plan.

OBJECTIVE: To differentiate the clinical features and computed tomography imaging features in the two types of mixed epithelial and stromal tumor of the kidney (MESTK) and to establish a treatment plan for the MESTK types. METHODS: Seventeen patients who underwent multidetector computed tomography (MDCT) before surgery and had a pathological diagnosis of MESTK were enrolled. Their clinical information (R.E.N.A.L. nephrometry score (R.E.N.A.L.-NS), radical nephrectomy (RN), partial nephrectomy (PN), etc.) were collected. The radiological features included renal sinus fat invagination (SFI), maximal diameter (MD), capsule and septa of the tumor, etc., were also analyzed. They were divided into two types according to the MDsolid /MDtumor ratio (solid type with >60%; cystic type with ≤60%). An independent-sample t-test and Fisher exact test were used to assess the differences between the two groups. RESULTS: MESTKs demonstrated a variable multi-septate cystic and solid components with a delayed enhancement. There were nine patients for solid type and eight patients for cystic type. Compared with solid type, the lesions in cystic type have larger MD (81.00 ± 37.91 vs. 41.22 ± 24.19, p = 0.020), higher R.E.N.A.L.-NS (10.03 ± 0.50 vs. 8.95 ± 1.26, p < 0.001), higher RN (75.00% vs. 22.22%, p = 0.015), larger SFI (87.5% vs. 33.3%, p = 0.05), more septa (100% vs. 0%, p < 0.001), and more capsule (100% vs. 11.1%, p < 0.001). CONCLUSION: Cystic type MESTK has more hazardous features (such as larger MD, higher R.E.N.A.L.-NS, more RN, greater SFI, multiple septa) compared with solid type, suggesting that RN is more suitable for cystic type and PN for solid type.

Non-contrast-enhanced abdominal MRA at 3 T using velocity-selective pulse trains.

PURPOSE: Most existing non-contrast-enhanced methods for abdominal MR arteriography rely on a spatially selective inversion (SSI) pulse with a delay to null both static tissue and venous blood, and are limited to small spatial coverage due to the sensitivity to slow arterial inflow. Velocity-selective inversion (VSI) based approach has been shown to preserve the arterial blood inside the imaging volume at 1.5 T. Recently, velocity-selective saturation (VSS) pulse trains were applied to suppress the static tissue and have been combined with SSI pulses for cerebral MR arteriography at 3 T. The aim of this study is to construct an abdominal MRA protocol with large spatial coverage at 3 T using advanced velocity-selective pulse trains. METHODS: Multiple velocity-selective MRA protocols with different sequence modules and 3D acquisition methods were evaluated. Sequences using VSS only as well as SSI+VSS and VSI+VSS preparations were then compared among a group of healthy young and middle-aged volunteers. Using MRA without any preparations as reference, relative signal ratios and relative contrast ratios of different vascular segments were quantitatively analyzed. RESULTS: Both SSI+VSS and VSI+VSS arteriograms achieved high artery-to-tissue and artery-to-vein relative contrast ratios above aortic bifurcation. The SSI+VSS sequence yielded lower signal at the bilateral iliac arteries than VSI+VSS, reflecting the benefit of the VSI preparation for imaging the distal branches. CONCLUSION: The feasibility of noncontrast 3D MR abdominal arteriography was demonstrated on healthy volunteers using a combination of VSS pulse trains and SSI or VSI pulse.

[Diagnosis and differential diagnosis for solitary fibrous tumor in the abdomen and pelvis by CT].

OBJECTIVE: To study the CT features for solitary fibrous tumor (SFT) in the abdomen and pelvis and to improve the diagnostic accuracy.
 Methods: Fourteen patients with SFT were collected in our hospital from January, 2011 to December, 2015. Characteristic of images were analyzed and compared for 10 SFT, which located outside the abdominal organs with extragastrointestinal stromal tumors (EGIST), leiomyosarcoma, and schwannoma.
 Results: Necrosis and cystic formation were frequently present in SFT in the abdomen and pelvis. CE-CT showed serpentine vessels along the periphery, while pattern of enhancement was map-like inhomogeneous progressive. Comparing with the EGIST or schwannoma, the difference of CT value in non-contrast and the arterial phase were statistically significant (P<0.05). The numbers of peritumoral circuity vessel were significantly different between SFT and EGIST (χ²=18.27, P<0.008) or between SFT and schwannoma (χ²=19.25, P<0.008). Comparing with the leiomyosarcoma or schwannoma, SFT located outside the abdominal organs. We found that tumor necrosis rate was significantly different between SFT and leiomyoscarcoma (χ²=8.00, P<0.008).
 Conclusion: SFT in the abdomen and pelvis show certain CT characteristics. The CT value in non-contrast and at the arterial phase, tumor necrosis rate, and serpentine vessels along the periphery were pivotal in differentiating SFT from leiomyosarcoma, EGIST and schwannoma.

[Diagnostic value of liver imaging reporting and data system MRI on primary hepatocellular carcinoma].

OBJECTIVE: To evaluate the diagnostic value of liver imaging reporting and classification criteria of data system (LI-RADS) MRI on primary hepatic carcinoma (HCC).
 METHODS: The MRI images of 100 patients (72 patients with HCC, 4 with regenerative nodules, 13 with hemangioma, 4 with liver cyst, 3 with Liver abscess, 2 with inflammatory pseudotumor, 1 with hepatic arteriovenous fistula, 1 with Limitations of steatosis) with liver disease were collected in Xiangya Hospital from January, 2014 to January, 2015. All patients were at the risk of HCC. The images were reviewed according to the LI-RADS categorization by American College of Radiology (ACR) under a condition of blindness to the pathological data. The sensitivity, specificity and the area under the ROC curve in the diagnosis of HCC with the LI-RADS categorization were calculated by three associate professors from the Department of Radiology, Xiangya Hospital.
 RESULTS: The area under the ROC curve was 0.925 in the 100 patients with HCC. Of the 100 pathologically confirmed patients, 20 cases were LR1 and LR2. However, the post-operation pathological examination showed benign tumor (negative predictive value was 100%). There were 25 HCC in 31 cases of LR3, 27 HCC in 29 cases of LR4 (positive predictive value was 93.1%). All of 20 cases of LR5 were HCC (positive predictive value was 100%). If LR1 and LR2 were considered negative, and LR3, 4, 5 were positive, then the sensitivity, the specificity and the area under the ROC curve was 100%, 71.4% and 0.925, respectively. If LR1, 2 and 3 were considered negative and LR4 and LR5 were positive, the sensitivity, the specificity and the area under the ROC curve was 100%, 90.9% and 0.974, respectively.
 CONCLUSION: The MRI LI-RADS categorization is highly sensitive and specific in the diagnosis of HCC, which can improve the diagnostic accuracy.

MiR-335 acts as a potential tumor suppressor miRNA via downregulating ROCK1 expression in hepatocellular carcinoma.

Increasing evidence has suggested that dysregulation of microRNAs (miRNAs) could contribute to tumor progression. Previous miRNA microarray analysis illustrated that miR-335 is downregulated in various cancers; however, the role of miR-335 on hepatocellular carcinoma (HCC) has not been well elucidated. In this study, we investigated the biological functions and molecular mechanisms of miR-335 in human HCC in vitro, discussing whether it could be a therapeutic biomarker of HCC in the future. Four HCC cell lines and samples from 62 patients with HCC were analyzed for the expression of miR-335 by quantitative RT-PCR. Overexpression of miR-335 was established by transfecting mimics into HepG2 and HuH7 cells. Cell proliferation and cell migration were assessed by cell viability assay and transwell assay. Luciferase reporter assay and Western blot were to verify ROCK1 as a novel target gene of miR-335. We observed that miR-335 was downregulated in human HCC tissues and in all four HCC cell lines. The MTT assay revealed that overexpression of miR-335 subsequently inhibited cell growth. Furthermore, the transwell assay also showed significant cell migration inhibition in miR-335 transfectant. The expression of ROCK1 was decreased evidently after overexpression of miR-335, indicating that ROCK1 is a target gene for miR-335. Our data revealed that miR-335 could inhibit the proliferation and migration invasion of HCC cells via regulating ROCK1, suggesting that miR-335 could be a therapeutic biomarker of HCC in the future.

A Rare Case of Extrauterine Endometrial Stromal Sarcoma Arising from Deep Pelvic Endometriosis: Role of Multidisciplinary Team Meeting.

INTRODUCTION: Extrauterine endometrial stromal sarcoma (EESS) arising from Deep pelvic endometriosis (DPE) has a poor life quality and is difficult to diagnose pre-operatively. However, the patient's quality of life can be improved when it is diagnosed precisely and managed successfully. CASE REPORT: A 35-year-old woman presented to our hospital with a 3-month history of hematochezia and anal pain. Initially, she was misdiagnosed as a rectal stromal tumor and then precisely diagnosed as having EESS from DPE following several multidisciplinary team (MDT) meetings. The lesion was shrunk by gonadotrophin-releasing hormone agonist (GnRH-α) treatment and then resected with minimal trauma. CONCLUSION: MDT is crucial in the treatment of the patient. It can promote individualized treatment and improve patient's quality of life.

Development of a radiomics nomogram to predict the treatment resistance of Chinese MPO-AAV patients with lung involvement: a two-center study.

Background: Previous studies from our group and other investigators have shown that lung involvement is one of the independent predictors for treatment resistance in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (MPO-AAV). However, it is unclear which image features of lung involvement can predict the therapeutic response in MPO-AAV patients, which is vital in decision-making for these patients. Our aim was to develop and validate a radiomics nomogram to predict treatment resistance of Chinese MPO-AAV patients based on low-dose multiple slices computed tomography (MSCT) of the involved lung with cohorts from two centers. Methods: A total of 151 MPO-AAV patients with lung involvement (MPO-AAV-LI) from two centers were enrolled. Two different models (Model 1: radiomics signature; Model 2: radiomics nomogram) were built based on the clinical and MSCT data to predict the treatment resistance of MPO-AAV with lung involvement in training and test cohorts. The performance of the models was assessed using the area under the curve (AUC). The better model was further validated. A nomogram was constructed and evaluated by DCA and calibration curves, which further tested in all enrolled data and compared with the other model. Results: Model 2 had a higher predicting ability than Model 1 both in training (AUC: 0.948 vs. 0.824; p = 0.039) and test cohorts (AUC: 0.913 vs. 0.898; p = 0.043). As a better model, Model 2 obtained an excellent predictive performance (AUC: 0.929; 95% CI: 0.827-1.000) in the validation cohort. The DCA curve demonstrated that Model 2 was clinically feasible. The calibration curves of Model 2 closely aligned with the true treatment resistance rate in the training (p = 0.28) and test sets (p = 0.70). In addition, the predictive performance of Model 2 (AUC: 0.929; 95% CI: 0.875-0.964) was superior to Model 1 (AUC: 0.862; 95% CI: 0.796-0.913) and serum creatinine (AUC: 0.867; 95% CI: 0.802-0.917) in all patients (all p< 0.05). Conclusion: The radiomics nomogram (Model 2) is a useful, non-invasive tool for predicting the treatment resistance of MPO-AAV patients with lung involvement, which might aid in individualizing treatment decisions.

Amide proton transfer (APT) and magnetization transfer (MT) in predicting short-term therapeutic outcome in nasopharyngeal carcinoma after chemoradiotherapy: a feasibility study of three-dimensional chemical exchange saturation transfer (CEST) MRI.

BACKGROUND: The three-dimensional chemical exchange saturation transfer (3D CEST) technique is a novel and promising magnetic resonance sequence; however, its application in nasopharyngeal carcinoma (NPC) lacks sufficient evaluation. This study aimed to assess the feasibility of the 3D CEST technique in predicting the short-term treatment outcomes for chemoradiotherapy (CRT) in NPC patients. METHODS: Forty NPC patients and fourteen healthy volunteers were enrolled and underwent the pre-treatment 3D CEST magnetic resonance imaging and diffusion-weighted imaging (DWI). The reliability of 3D CEST was assessed in healthy volunteers by calculating the intra- and inter-observer correlation coefficient (ICC) for amide proton transfer weighted-signal intensity (APTw-SI) and magnetization transfer ratio (MTR) values. NPC patients were divided into residual and non-residual groups based on short-term treatment outcomes after CRT. Whole-tumor regions of interest (ROIs) were manually drawn to measure APTw-SI, MTR and apparent diffusion coefficient (ADC) values. Multivariate analysis and the receiver operating characteristic curve (ROC) were used to evaluate the prediction performance of clinical characteristics, APTw-SI, MTR, ADC values, and combined models in predicting short-term treatment outcomes in NPC patients. RESULTS: For the healthy volunteer group, all APTw-SI and MTR values exhibited good to excellent intra- and inter-observer agreements (0.736-0.910, 0.895-0.981, all P > 0.05). For NPC patients, MTR values showed a significant difference between the non-residual and residual groups (31.24 ± 5.21% vs. 34.74 ± 1.54%, P = 0.003) while no significant differences were observed for APTw-SI and ADC values (P > 0.05). Moreover, the diagnostic power of MTR value was superior to APTw-SI (AUC: 0.818 vs. 0.521, P = 0.017) and comparable to ADC values (AUC: 0.818 vs. 0.649, P > 0.05) in predicting short-term treatment outcomes for NPC patients. The prediction performance did not improve even when combining MTR values with APTw-SI and/or ADC values (P > 0.05). CONCLUSIONS: The pre-treatment MTR value acquired through 3D CEST demonstrated superior predictive performance for short-term treatment outcomes compared to APTw-SI and ADC values in NPC patients after CRT.

Evaluation of renal artery in hypertensive patients by unenhanced MR angiography using spatial labeling with multiple inversion pulses sequence and by CT angiography.

OBJECTIVE: The purposes of this study were to determine the performance of a new unenhanced MR angiography (MRA) sequence, spatial labeling with multiple inversion pulses (SLEEK), with regard to its ability to present the renal arteries and to reveal renal artery disease in patients with secondary hypertension. SUBJECTS AND METHODS: Unenhanced MRA using SLEEK was performed on a 1.5-T MRI system for assessing renal arteries in 50 patients with hypertension. Then all patients underwent CT angiography (CTA) within 1-7 days. The ability to present the renal arteries and to reveal renal artery disease with SLEEK was evaluated by two experienced radiologists and was compared with CTA results using a joint reading performed in consensus. RESULTS: Forty-six patients with hypertension successfully underwent SLEEK MRA. A total of 119 renal arteries were assessed, including 86 normal arteries, 26 with stenoses, and seven with fibromuscular dysplasia on CTA. There was excellent correlation between SLEEK and CTA in presenting the degree of renal artery stenosis (r(s) = 0.851; p < 0.05). SLEEK was superior to CTA in revealing the third- and fourth-order segmental branches in the renal parenchyma (p < 0.05). SLEEK has the advantage of avoiding interference from vertebra, atherosclerotic plaques, and early venous system enhancement. CONCLUSION: Unenhanced MRA using SLEEK is a reliable diagnostic method for evaluating renal artery disease and revealing segmental branches in the renal parenchyma. It is relatively inexpensive and is not associated with renal complications. It can be used as an alternative to CTA for screening for renal artery disease, especially in patients with hypertension and renal insufficiency.

Accelerated loss of trunk muscle density and size at L1 vertebral level in male patients with COPD.

Background and purpose: Weight loss and muscle mass loss are common in patients with chronic obstructive pulmonary disease (COPD). Muscle density and fat infiltration based on CT images may be more sensitive than muscle mass by DXA in the assessment of sarcopenia for COPD patients. However, the age-related changes of cross-sectional trunk muscle compositions based on lung CT scans are still unknown. Thus, we aimed to investigate over time the change in muscle density, size, and fat deposition of L1-level trunk muscles in patients with COPD. Materials and methods: 129 male COPD patients with a second chest CT scan (from 2013-2019 to 2014-2020) were enrolled. The CT images at first and second CT scans are analyzed by OsiriX software. Trunk muscles at the level of the 1st lumbar vertebrae were selected for analysis. Attenuation of lumbar vertebrae 1 was also measured from chest CT images. The pulmonary function values were calculated based on forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Results: The mean age of the 129 patients with COPD was 69.7 years. The durations of COPD of this cohort were from 8-17 years. The mean area and density of L1 trunk muscles were 85.5 cm2 and 36.4 HU. At baseline, muscle area and density and vertebral density were negatively associated with age (p<0.0001), while the intermuscular fat area and the fat infiltration ratio were not significantly associated with age (p>0.05). The per-year loss of trunk muscle area was 2.83 cm2 (p<0.0001) which accounts for 3.3% decrease per year, and the per-year decrease of trunk muscle density was 2.41 HU (p<0.0001) which accounts for 6.6% decrease per year. The per-year increase of intermuscular fat in trunk muscles was 0.57 cm2 (p=0.006) which accounts for 11.1% increase per year. The bone density loss was 5.63 HU/per year (p<0.0001). Conclusion: Men with COPD had accelerated muscle loss as well as increased fat infiltration. Compared to muscle quantity loss, the decline in muscle quality is much larger, indicating the importance of relevant interventions focusing on improving muscle quality.

Development and validation of MRI-based model for the preoperative prediction of macrotrabecular hepatocellular carcinoma subtype.

BACKGROUND: Macrotrabecular hepatocellular carcinoma (MTHCC) has a poor prognosis and is difficult to diagnose preoperatively. The purpose is to build and validate MRI-based models to predict the MTHCC subtype. METHODS: Two hundred eight patients with confirmed HCC were enrolled. Three models (model 1: clinicoradiologic model; model 2: fusion radiomics signature; model 3: combined model 1 and model 2) were built based on their clinical data and MR images to predict MTHCC in training and validation cohorts. The performance of the models was assessed using the area under the curve (AUC). The clinical utility of the models was estimated by decision curve analysis (DCA). A nomogram was constructed, and its calibration was evaluated. RESULTS: Model 1 is easier to build than models 2 and 3, with a good AUC of 0.773 (95% CI 0.696-0.838) and 0.801 (95% CI 0.681-0.891) in predicting MTHCC in training and validation cohorts, respectively. It performed slightly superior to model 2 in both training (AUC 0.747; 95% CI 0.689-0.806; p = 0.548) and validation (AUC 0.718; 95% CI 0.618-0.810; p = 0.089) cohorts and was similar to model 3 in the validation (AUC 0.866; 95% CI 0.801-0.928; p = 0.321) but inferior in the training (AUC 0.889; 95% CI 0.851-0.926; p = 0.001) cohorts. The DCA of model 1 had a higher net benefit than the treat-all and treat-none strategy at a threshold probability of 10%. The calibration curves of model 1 closely aligned with the true MTHCC rates in the training (p = 0.355) and validation sets (p = 0.364). CONCLUSION: The clinicoradiologic model has a good performance in diagnosing MTHCC, and it is simpler and easier to implement, making it a valuable tool for pretherapeutic decision-making in patients.

Comparing the clinical utility of single-shot, readout-segmented and zoomit echo-planar imaging in diffusion-weighted imaging of the kidney at 3 T.

We compared the clinical utility of single-shot echo-planar imaging (SS-EPI) using different breathing schemes, readout-segmented EPI and zoomit EPI in the repeatability of apparent diffusion coefficient (ADC) measurements, cortico-medullary contrast to noise ratio (c-mCNR) and image quality. In this institutional review board-approved prospective study, some common clinically applicable diffusion-weighted imaging (b = 50, 400, 800 s/mm2) of kidney on 3.0 T MRI were performed on 22 volunteers using SS-EPI with breath-hold diffusion-weighted imaging (BH-DWI), free-breathing (FB-DWI), navigator-triggered (NT-DWI) and respiratory-triggered (RT-DWI), readout-segmented DWI (RS-DWI), and Zoomit DWI (Z-DWI). ADC and c-mCNR were measured in 12 anatomic locations (the upper, middle, and lower pole of the renal cortex and medulla), and image quality was assessed on these DWI sequences. A DWI with the optimal clinical utility was decided by systematically assessing the ADC repeatability, c-mCNR and image quality among the DWIs. For ADC measurements, Z-DWI had an excellent intra-observer agreement (intra-class correlation coefficients (ICCs): 0.876-0.944) and good inter-observer agreement (inter-class ICCs: 0.798-0.856) in six DWI sequences. Z-DWI had the highest ADC repeatability in most of the 12 anatomic locations of the kidneys (mean ADC absolute difference: 0.070-0.111 × 10-3 mm2/s, limit of agreement: 0.031-0.056 × 10-3 mm2/s). In all DWIs, Z-DWI yielded a slightly higher c-mCNR than other DWIs in most representative locations (P > 0.05), which was significantly higher than BH-DWI and FB-DWI in the middle pole of both kidneys and the upper pole of the left kidney (P < 0.05). In addition, Z-DWI yielded image quality that was similar to RT-DWI and NT-DWI (P > 0.05) and superior to BH-DWI, FB-DWI and RS-DWI (P < 0.05). Our results suggest that Z-DWI provides the highest ADC reproducibility, better c-mCNR and good image quality on 3.0 T MRI, making it the recommended sequence for clinical DWI of the kidney.

Predicting the prognosis of hepatocellular carcinoma with the treatment of transcatheter arterial chemoembolization combined with microwave ablation using pretreatment MR imaging texture features.

OBJECTIVE: To investigate the prognostic value of baseline magnetic resonance imaging (MRI) texture analysis of hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE) and microwave ablation (MWA). METHODS: MRI was performed on 102 patients with HCC before receiving TACE combined with MWA in this retrospective study. The best 10 texture features were screened as a feature group for each MRI sequence by MaZda software using mutual information coefficient (MI), nonlinear discriminant analysis (NDA) and other methods. The optimal feature group with the lowest misdiagnosis rate was achieved on one MRI sequence between two groups dichotomized by 3-year survival, which was used to optimize the significant texture features with the optimal cutoff values. The Cox proportional hazards model was generated for the significant texture features and clinical variables to determine the independent predictors of overall survival (OS). The predictive performance of the model was further evaluated by the area under the ROC curve (AUC). Kaplan-Meier and log-rank tests were performed for disease-free survival (DFS) and Local recurrence-free survival (LRFS). RESULTS: The optimal feature group with the lowest misdiagnosis rate of 8.82% was obtained on T2WI using MI combined with NDA feature analysis. For Cox proportional hazards regression models, the independent prognostic factors associated with OS were albumin (P = 0.047), BCLC stage (P = 0.001), Correlat(1,- 1)T2 (P = 0.01) and SumEntrp(3,0)T2 (P = 0.015), and the prediction efficiency of multivariate model is AUC = 0.876, 95%CI = 0.803-0.949. Kaplan-Meier analyses further demonstrated that BCLC (P < 0.001), Correlat(1,- 1)T2 (P = 0.023) and SumEntrp(3,0)T2 (P < 0.001) were associated with DFS, and BCLC (P = 0.007) related to LRFS. CONCLUSIONS: MR imaging texture features may be used to predict the prognosis of HCC treated with TACE combined with MWA.

Comparing the clinical utility of single-shot echo-planar imaging and readout-segmented echo-planar imaging in diffusion-weighted imaging of the liver at 3 tesla.

PURPOSE: To compare the clinical utility of single-shot echo-planar imaging (SS-EPI) using different breathing schemes and readout-segmented EPI (RS-EPI) in the repeatability of apparent diffusion coefficient (ADC) measurements, signal-to-noise ratio (SNR) and image quality. METHODS: In this institutional review board-approved prospective study, hepatic DWIs (b = 50, 300, 600 s/mm2) were performed in 22 volunteers on 3.0 T MRI using SS-EPI with free-breathing diffusion-weighted imaging (FB-DWI), breath-hold (BH-DWI), respiratory-triggered (RT-DWI) and navigator-triggered (NT-DWI), and readout-segmented EPI (RS-DWI). ADC and surrogate SNR (sSNR) were measured in nine anatomic locations in the right lobe, and image quality was assessed on all FB-DWI, BH-DWI, RT-DWI, NT-DWI, and RS-DWI sequences. The sequence with the optimal clinical utility was decided by systematically comparing the ADC repeatability, sSNR and image quality of the above DWIs. RESULTS: In all the five sequences, NT-DWI had the most reliable intra-observer agreement (intraclass correlation coefficient (ICC): 0.900-0.922; all P > 0.05), and a better interobserver agreement (ICC: 0.853-0.960; all p > 0.05) than RS-DWI (ICC:0.881-0.916; some P < 0.05). NT-DWI had the best ADC repeatability in the nine locations (mean ADC absolute differences: 38.47-56.38 × 10-6 mm2/s, limits of agreement (LOA): 17.33-22.52 × 10-6 mm2/s). Also, NT-DWI had the highest sSNR (Reader 1: 50.58 ±â€¯20.11 (Superior), 74.06 ±â€¯28.37 (Central), 80.99 ±â€¯38.11(Inferior)); Reader 2: 48.07 ±â€¯23.92 (Superior), 68.23 ±â€¯32.91 (Central), 76.78 ±â€¯33.07 (Inferior)) in three representative sections except for RS-DWI. Furthermore, NT-DWI had a better image quality than RS-DWI (P < 0.05) and was superior to FB-DWI and BH-DWI in sharpness of the liver (at b = 300 s/mm2) (P < 0.05) CONCLUSION: RS-DWI has the best SNR. However, NT-DWI can provide sufficient SNR, excellent image quality, and the best ADC repeatability on 3.0 T MRI. It is thus the recommended sequence for the clinical application of hepatic DWI.

Rectal Tumor Stiffness Quantified by In Vivo Tomoelastography and Collagen Content Estimated by Histopathology Predict Tumor Aggressiveness.

PURPOSE: To investigate the significance of collagen in predicting the aggressiveness of rectal tumors in patients, examined in vivo based on tomoelastography quantified stiffness and ex vivo by histologically measured collagen volume fraction (CVF). EXPERIMENTAL DESIGN: 170 patients with suspected rectal cancer were prospectively enrolled and underwent preoperative magnetic resonance imaging (MRI) and rectal tomoelastography, a technique based on multifrequency magnetic resonance elastography. Histopathologic analysis identified eighty patients with rectal cancer who were divided into subgroups by tumor-node (TN) stage, prognostic stage, and risk level. Rectal tumor stiffness was correlated with histopathologic CVF. Area-under-the-curve (AUC) and contingency analysis were used to evaluate the performance of rectal stiffness in distinguishing tumor stages which was compared to standard clinical MRI. RESULTS: In vivo tomoelastography revealed that rectal tumor stiffened significantly with increased TN stage (p<0.05). Tumors with poorly differentiated status, perineural and lymphovascular invasion also displayed higher stiffness than well-to-moderately differentiated, noninvasive tumors (all p<0.05). Similar to in vivo stiffness, CVF indicated an abnormally high collagen content in tumors with perineural invasion and poor differentiation status. CVF was also positively correlated with stiffness (p<0.05). Most importantly, both stiffness (AUROC: 0.82) and CVF (AUROC: 0.89) demonstrated very good diagnostic accuracy in detecting rectal tumors that have high risk for progressing to an aggressive state with poorer prognosis. CONCLUSION: In human rectal carcinomas, overexpression of collagen is correlated with increased tissue stiffness and high risk for tumor advancing more aggressively. In vivo tomoelastography quantifies rectal tumor stiffness which improves the diagnostic performance of standard MRI in the assessment of lymph nodes metastasis. Therefore, in vivo stiffness mapping by tomoelastography can predict rectal tumor aggressiveness and add diagnostic value to MRI.

Highly efficient magnetic labelling allows MRI tracking of the homing of stem cell-derived extracellular vesicles following systemic delivery.

Human stem-cell-derived extracellular vesicles (EVs) are currently being investigated for cell-free therapy in regenerative medicine applications, but the lack of noninvasive imaging methods to track EV homing and uptake in injured tissues has limited the refinement and optimization of the approach. Here, we developed a new labelling strategy to prepare magnetic EVs (magneto-EVs) allowing sensitive yet specific MRI tracking of systemically injected therapeutic EVs. This new labelling strategy relies on the use of 'sticky' magnetic particles, namely superparamagnetic iron oxide (SPIO) nanoparticles coated with polyhistidine tags, to efficiently separate magneto-EVs from unencapsulated SPIO particles. Using this method, we prepared pluripotent stem cell (iPSC)-derived magneto-EVs and subsequently used MRI to track their homing in different animal models of kidney injury and myocardial ischemia. Our results showed that iPSC-derived EVs preferentially accumulated in the injury sites and conferred substantial protection. Our study paves a new pathway for preparing highly purified magnetic EVs and tracking them using MRI towards optimized, systemically administered EV-based cell-free therapies.

Time-dependent changes in CT of radiation-induced liver injury: a preliminary study in gastric cancer patients.

In this study, the time-dependent changes on dynamic computed tomograph (CT) of radiation-induced liver injury in gastric cancer patients was examined. The CT images of 52 gastric cancer patients who had received chemoradiotherapies were reviewed on the PACS system. Dynamic CT scan was performed in all the subjects. Our results showed that 18 patients were found to have radiation-induced liver injury. The CT findings of radiation-induced liver injury in gastric cancer patients tend to show up one month after radiation treatment. The damaged area was of low density on all three phases, and then it was enhanced on portal vein phase or delay phase. The focal radiation reaction of liver without basic disease vanished 9-11 months later after treatment. We are led to conclude that dynamic CT is of help in the diagnosis of CRT-induced liver injury, and it may be the method of choice for following up the whole course of the CRT-induced liver injury, i.e., form hepatic damage to healing. The classification of CT findings we recommend can avoid the influence of technological factors, and thereby serve as a better guide for treatment of CRT-induced liver injury.

Comparing Chinese children and adults with RT-PCR positive COVID-19: A systematic review.

BACKGROUND: The various clinical manifestations of COVID-19 with RT-PCR positive patients have been reported. However, the differences in the clinical presentation between children and adults were unclear. Thus, we aimed to investigate the differences in the clinical manifestations and imaging characteristics between Chinese children and adults with COVID-19 by systematically analyzing the data derived from some latest literatures. METHODS: An extensive search of COVID-19 papers was conducted in PubMed and Chinese medical journal network, and relevant articles were selected based on some standard requirements. The included papers were analyzed for differences in clinical manifestation between children and adults with COVID-19 after the quality evaluation with the QUADAS-2 tool. The differences in the clinical features and CT findings were analyzed using a Pearson χ2 test or Fisher's exact test. Patients who underwent CT examination were divided into the initial examination (0-4days) and follow-up examination groups (5-14 days). RESULTS: A total of 345patients (70 children and 275 adults) with RT- PCR (+) were included in our study (5 papers for children and 5 papers for adult groups). Significant differences between children and adults were found in exposure history (p < 0.001, χ2 = 166.890), fever (p = 0.016, χ2 = 5.757), white cell count (p < 0.001, χ2 = 14.043), and CT features in the initial (p < 0.001, χ2 = 60.653) and follow-up stages (p < 0.001, χ2 = 52.924); and the involved lung in the follow-up stage (p ＜ 0.001, χ2 = 16.776). CONCLUSIONS: Some differences have been presented between children and adults with RT-PCR positive COVID-19, which are helpful in the management and protection of children with COVID-19.

The application of texture quantification in hepatocellular carcinoma using CT and MRI: a review of perspectives and challenges.

Recently, radiomic texture quantification of tumors has received much attention from radiologists, scientists, and stakeholders because several results have shown the feasibility of using the technique to diagnose and manage oncological conditions. In patients with hepatocellular carcinoma, radiomics has been applied in all stages of tumor evaluation, including diagnosis and characterization of the genotypic behavior of the tumor, monitoring of treatment responses and prediction of various clinical endpoints. It is also useful in selecting suitable candidates for specific treatment strategies. However, the clinical validation of hepatocellular carcinoma radiomics is limited by challenges in imaging protocol and data acquisition parameters, challenges in segmentation techniques, dimensionality reduction, and modeling methods. Identification of the best segmentation and optimal modeling methods, as well as texture features most stable to imaging protocol variability would go a long way in harmonizing HCC radiomics for personalized patient care. This article reviews the process of HCC radiomics, its clinical applications, associated challenges, and current optimization strategies.