Relative Signal Intensity Research Articles

Novel Characteristic Skull Magnetic Resonance Imaging Features Associated With Meningioma

Meningioma-related skull magnetic resonance imaging findings other than hyperostosis are not widely recognized. We evaluated the novel findings of the skull adjacent to meningiomas. Records from patients with meningiomas located adjacent to the skull on magnetic resonance imaging (n = 32) were included. Three skull findings (intramedullary prominent vessel, intramedullary enhancement, intramedullary T2-hyperintensity) and the widely known hyperostosis were retrospectively visually assessed. The frequency of these 3 findings and the relevance to each other, and their relationships with hyperostosis, size, length adjacent to the skull, and relative signal intensity of the meningioma were examined. The incidence of the three findings was 46.88%, 53.13%, and 62.5%, respectively, and that of hyperostosis was 46.88%. Each association involving the findings was strong, and they were significantly related to the size and length. Intramedullary prominent vessel, intramedullary enhancement, and intramedullary T2-hyperintensity may be novel characteristic skull findings associated with meningioma.

Developing a prediction model based on MRI for pathological complete response after neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

The aim of this study was to build an appropriate diagnostic model for predicting pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC), by combining magnetic resonance imaging (MRI) parameters with clinical factors. Eighty-four patients with LARC who underwent MR examination before and after nCRT were enrolled in this study. MRI parameters including cylindrical approximated tumor volume (CATV) and relative signal intensity of tumor (rT2wSI) were measured; corresponding reduction rates (RR) were calculated; and MR tumor regression grade (mrTRG) and other conventional MRI parameters were assessed. Logistic regression with lasso regularization was performed and the appropriate prediction model for pCR was built up. An external cohort of thirty-six patients was used as the validation group for testing the model. Receiver-operating characteristic (ROC) analysis was used to assess the diagnostic performance. In the development and the validation group, 17 patients (20.2%) and 11 patients (30.6%), respectively, achieved pCR. Two CATV-related parameters (CATVpost, which is the CATV measured after nCRT and CATVRR), one rT2wSI-related parameter (rT2wSIRR), and mrTRG were the most important parameters for predicting pCR and were retained in the diagnostic model. In the development group, the area under the receiver-operating characteristic curve (AUC) for predicting pCR is 0.88 [95% confidence interval (CI) 0.78-0.97, p < 0.001], with a sensitivity of 82.4% and a specificity of 83.6%. In the validation group, the AUC is 0.84 (95% CI 0.70-0.98, p = 0.001), with a sensitivity of 81.8% and a specificity of 76.0%. A diagnostic model including CATVpost, CATVRR, rT2wSIRR, and mrTRG was useful for predicting pCR after nCRT in patients with LARC and may be used as an effective organ-preservation strategy.

Temporomandibular joint morphology does not influence the presence of arthralgia in patients with disk displacement with reduction: a magnetic resonance imaging-based study.

The aim of this study was to compare, by using magnetic resonance imaging (MRI), temporomandibular joint (TMJ) morphology between patients with disk displacement with reduction (DDWR) with or without arthralgia and a control group and to identify which factors are associated with the concomitant presence of arthralgia in DDWR patients. In this investigation, 36 TMJ MRIs were divided into 3 groups. Group 1 (n = 12) comprised patients with DDWR and arthralgia; group 2 (n = 12) comprised patients with DDWR without arthralgia; and group 3 (n = 12) was the control group. Disk and mandibular condyle morphologies; articular eminence morphology and inclination; size of the mandibular fossa; joint space size; joint effusion; bone marrow of the mandibular condyle; and the relative signal intensity of retrodiscal tissue were evaluated. Fisher's exact test and 1-way analysis of variance (ANOVA) revealed no significant differences (P > .05) between groups for any variable. Logistic regression analysis showed that no anatomic variables were related to the concomitant presence of arthralgia in patients with DDWR (P > .05). As evaluated on MRI scans, no significant differences in the anatomic characteristics of the TMJ were detected between DDWR patients with or without concomitant arthralgia and the control group. There were no factors associated with the concomitant presence of arthralgia in patients with DDWR.

Pressure enabled drug delivery of anti-CEA CAR-T cells increases intra-hepatic CAR-T tumor penetration and therapeutic index in a murine model of liver metastasis

Abstract Introduction We have demonstrated safety and clinical activity with anti-CEA CAR-T (Sorrento/TNK Therapeutics, Inc.) regional infusions for treatment of liver metastases (LM) using a pressure-enabled drug delivery device (PEDD™, TriSalus™ Life Sciences, Inc.) to increase CAR-T penetration. To further explore the potential benefit of PEDD, we developed a pre-clinical murine LM model that enables correlation of infusion pressure with response. Methodology Mice with CEA+ LM were infused with anti-CEA CAR-T into the portal vein with specified rate and pressure levels. Flow cytometry (FC), bioluminescence imaging (BLI), and serum liver function tests (LFTs) were conducted at multiple time points. Results Flow-pressure relationship was established with ΔP of 7.23 mmHg vs 2.33 mmHg (p=0.01) in high-pressure (10 mL/min, HP) and low-pressure (1 mL/min, LP) cohorts. FC assessment of hepatic non-parenchymal cells 1d after infusion demonstrated 15.9% CD3+CAR+ in HP, compared to 5.1% in LP (p=0.0004). Tumor BLI at day 3 (geometric mean relative to baseline) showed significantly enhanced therapeutic effect in HP, −18% relative signal intensity (RSI), compared to +148% RSI in LP (p=0.05) or +178% RSI in controls (p=0.04). LFTs were similar in LP and HP groups with AST 302 vs 437 U/L (p=0.60) and total bilirubin 0.25 vs 0.7 mg/dL (p=0.33), respectively. Conclusions HP delivery correlated with enhanced CAR-T delivery and control of tumor growth, without an increase in liver toxicity. Follow up to this proof of concept study will investigate multiple infusions with combinatorial approaches with the goal of durable tumor eradication. An ongoing clinical study will further explore CAR-T PEDD in patients.

Effect of ultrasound-assisted osmotic dehydration pretreatment on the infrared drying of Pakchoi Stems

The effect of ultrasound-assisted osmotic dehydration (UOD) prior to infrared drying (IR) on the drying time and quality properties of dried Pakchoi stems was studied. Results suggested that the ultrasound application could significantly increase the mass transfer during the osmotic process. The UOD pretreated samples showed higher relaxation times of T23 and lower relative signal intensities of A23 using low-field nuclear magnetic resonance (LF-NMR) analysis. Moreover, the cell structural damage and mircrochannel formation caused by the UOD pretreatment resulted in a 25 ∼ 42% reduction in drying time. Although, the chlorophyl and ascorbic acid contents of IR dried Pakchoi stems with UOD pretreatment were relatively lower in comparison with those of untreated samples, the color was better retained and the rehydration ratio was significantly improved by UOD pretreatments.

A Complete Survey of Glycoalkaloids Using LC-FTICR-MS and IRMPD in a Commercial Variety and a Local Landrace of Eggplant (Solanum melongena L.) and their Anticholinesterase and Antioxidant Activities.

Eggplant contains glycoalkaloids (GAs), a class of nitrogen-containing secondary metabolites of great structural variety that may have both adverse and beneficial biological effects. In this study, we performed a complete survey of GAs and their malonylated form, in two genotypes of eggplants: A commercial cultivated type, Mirabella (Mir), with purple peel and bitter taste and a local landrace, named Melanzana Bianca di Senise (Sen), characterized by white peel with purple strip and a typical sweet aroma. Besides the analysis of their morphological traits, nineteen glycoalkaloids were tentatively identified in eggplant berry extracts based upon LC-ESI-FTICR-MS analysis using retention times, elution orders, high-resolution mass spectra, as well as high-resolution fragmentation by IRMPD. The relative signal intensities (i.e., ion counts) of the GAs identified in Mir and Sen pulp extracts showed as solamargine, and its isomers are the most abundant. In addition, anticholinesterase and antioxidant activities of the extracts were evaluated. Pulp tissue was found to be more active in inhibiting acetylcholinesterase enzyme than peel showing an inhibitory effect higher than 20% for Mir pulp. The identification of new malonylated GAs in eggplant is proposed.

Comparison of Magnetic Resonance Imaging and Ultrasonography in Diagnosing and Grading Carpal Tunnel Syndrome: A Prospective Study

ObjectiveTo use anatomic measurements on magnetic resonance imaging (MRI) and ultrasonography (USG) in diagnosing and grading carpal tunnel syndrome (CTS) using nerve conduction studies (NCS) as the gold standard. Material and methodsIn this prospective study, 26 patients with CTS (45 wrists; 22 female and 4 male patients; mean ± SD age of 49.42 + 14.47 years) and 19 age and sex matched healthy volunteers (32 wrists; 15 female and 4 male volunteers, mean ± SD age of 42.52 + 10.85 years) underwent MRI and USG. Cross-sectional area (CA) of median nerve was measured using free hand ROI at four levels: hamate hook (H0), pisiform bone (PI0), 1 cm proximal (PI1) and 2 cm proximal to PI0 (PI2). Relative median nerve signal intensity (MNSI) was calculated as ratio of median nerve signal intensity with hypothenar muscle signal intensity. Flexor retinacular bowing was calculated at hamate hook level. Echogenicity and Power Doppler vascularity of median nerve were assessed on USG. Independent t-test, chi square test and receiver operating characteristic curve analysis were used as appropriate. ResultsOn USG, CA measured at PI0 (95% confidence interval of 0.872-0.987) and retinacular bowing (0.816-0.912), while, on MRI, CA at PI1 (0.874-0.997) were most useful in diagnosing CTS based on the ROC and Zombie plot analysis. Area under curves for CA measurements on USG and MRI were not significantly different. CA at PI1 on MRI (0.752-0.965) was significantly different between minimal to moderate CTS and severe to extreme CTS groups (on NCS). ConclusionCA of median nerve is the most useful parameter to diagnose and grade CTS and USG and MRI are comparable for measurements. Increased retinacular bowing on USG and hypoechogenicity of median nerve increase the diagnostic confidence while MRI helps in picking up important associated conditions.

Differentiation of Benign from Malignant Adnexal Masses by Dynamic Contrast-Enhanced MRI (DCE-MRI): Quantitative and Semi-quantitative analysis at 3-Tesla MRI

Background:To evaluate the utility of the pharmacokinetic modeling derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating benign from malignant adnexal masses. Methods:A total of 43 patients with 49 complex adnexal masses (27 benign, 3 borderline, and 19 malignant lesions) underwent preoperative DCE-MRI examinations on a 3 Tesla MRI. Using extended Tofts’ model, quantitative analysis was performed in the solid components of all tumors. Three pharmacokinetic parameters were defined as volume transfer coefficient (Ktrans), the rate constant (Kep), and the plasma volume (Vp). Semi-quantitative analysis was also performed and the values of relative signal intensity (SI rel) wash-in-rate (WIR), the initial area under the curve (iAUC60), time-to-peak (TTP) and wash-out-rate (WOR) were calculated. Receiver operating characteristic (ROC) curve analysis was performed to evaluate diagnostic characteristics of each DCE-MRI parameter in differentiating borderline/malignant tumors from benign lesions and to provide the optimal cutoff values for these variables.Results:SI rel had the highest diagnostic value (AUC=0.872; p<0.001; cut-off=121.4 associated with an overall accuracy=79.6%, sensitivity=95.5%, specificity=66.7%, NPV=94.8% and PPV=70.0%). Ktrans had the second highest AUC=0.836 (p<0.001; cut-off=0.034 associated with an overall accuracy=79.6%, sensitivity=86.4%, specificity=74.1%, NPV=87.0% and PPV=73.1%). The other factors found to be acceptable diagnostic parameters for borderline/malignant lesions included WIR (AUC=0.816; p<0.001), iAUC60 (AUC=0.808; p<0.001), Vp (AUC=0.795; p<0.001), SI max (AUC=0.737, p=0.005), SI peak (AUC=0.737; p=0.005) and Kep (AUC=0.681; p=0.031). Conclusion:Quantitative DCE-MRI is a relevant tool for differentiating benign from malignant adnexal masses. Among all the DCE parameters, SI rel and Ktrans are the most accurate discriminators.

Pitfall in the detection of acute lesions of transient ischemic attack with fluid-inversion prepared diffusion weighted imaging

Objective To explore the limits of fluid-inversion prepared diffusion weighted imaging (FLIPD) in detection of acute cerebral ischemic lesions. Methods From January 2012 to March 2014, forty-nine patients (33 males, 16 females, age (55.6±12.3) years) clinically diagnosed as transient ischemic attack (TIA) were included. Patients underwent brain MRI (conventional diffusion weighted imaging (DWI) and FLIPD) within 3 d after the onset of TIA. The detection ability of MRI with the two sequences was compared, and the relative signal intensity (rSI) and apparent diffusion coefficient (ADC) of acute ischemic lesions based on two sequences were compared. Kappa test and two-sample t test were used to analyze the data. Results A total of 87 acute ischemic lesions were detected in 21 patients by conventional DWI, and 54 were detected in 19 patients by FLIPD (Kappa=0.916, P<0.05). The rSI of ischemic lesions on FLIPD was significantly lower than that on conventional DWI (1.37±0.22 vs 1.57±0.26; t=6.647, P<0.001). The ADC value of ischemic lesions on FLIPD was slightly lower than that on conventional DWI: (0.54 ±0.10) ×10-3 mm2/s vs (0.57±0.13)×10-3 mm2/s (t=2.120, P<0.05). The missed lesions on FLIPD were located in the white matter (n=18), cerebellum and brainstem (n=8), and the cortex (n=7). Conclusions A slight diffuse abnormality may be missed on FLIPD, so this method is not suitable for the detection of acute ischemic lesions. FLIPD technology still needs improvement. Key words: Ischemic attack, transient; Diffusion magnetic resonance imaging; Fluid attenuated inversion recovery sequence

Effect of bilateral carotid occlusion on cerebral hemodynamics and perivascular innervation: An experimental rat model.

We aimed to investigate the effect of chronic cerebral hypoperfusion on cerebral hemodynamics and perivascular nerve density in a rat model. Bilateral common carotid artery (CCA) ligation (n = 24) or sham‐operation (n = 24) was performed with a 1‐week interval. A subgroup (ligated n = 6; sham‐operated n = 3) underwent magnetic resonance imaging (MRI) before the procedures and 2 and 4 weeks after the second procedure. After termination, carotids were harvested for assessment of complete ligation and nerve density in cerebral arteries that were stained for the general neural marker PGP 9.5 and sympathetic marker TH by computerized image analysis. Five rats were excluded because of incomplete ligation. MRI‐based tortuosity of the posterior communicating artery (Pcom), first part of the posterior cerebral artery (P1) and basilar artery was observed in the ligated group, as well as an increased volume (p = 0.05) and relative signal intensity in the basilar artery (p = 0.04; sham‐group unchanged). Immunohistochemical analysis revealed that compared to sham‐operated rats, ligated rats had increased diameters of all intracircular segments and the extracircular part of the internal carotid artery (p < 0.05). Ligated rats showed a higher general nerve density compared to controls in P1 (10%, IQR:8.7–10.5 vs. 6.6%, IQR:5.5–7.4, p = 0.003) and Pcom segments (6.4%, IQR:5.8–6.5 vs. 3.2%, IQR:2.4–4.3, p = 0.003) and higher sympathetic nerve density in Pcom segments (3.7%, IQR:2.8–4.8 vs. 1.7%, IQR:1.3–2.2, p = 0.02). Bilateral CCA occlusion resulted in redistribution of blood flow to posteriorly located cerebral arteries with remarkable changes in morphology and perivascular nerve density, suggesting a functional role for perivascular nerves in cerebral autoregulation.

Nondestructive Early Detection of Bruising in Pear Fruit Using Optical Coherence Tomography

Pear fruit is susceptible to mechanical injury during harvesting, packaging, and transportation. Optical coherence tomography (OCT) can provide information concerning chemical and microstructural changes of fruit tissues. Therefore, using OCT to evaluate fruit quality is of great significance. In this study, OCT was used for early detection of subtle bruise symptoms underneath the pear peel. First, the signal intensity versus depth in relation to the OCT images of fruit tissue was determined, which was derived from the values of the OCT signal slope (OCTSS) and 1/e light penetration depth (D1/e). Furthermore, shaping (α) and scaling (β) indices were estimated by fitting a gamma distribution function to the signal intensity profile. After mechanical injury, OCTSS, α, and β decreased and the D1/e value increased. Distribution analysis of the relationship between α versus β served as an effective method to identify tissue bruising at an early stage. In conclusion, the results suggest that OCTSS, D1/e, and the α versus β distribution are closely correlated with bruise injury in pear fruit tissues. Thus, OCT is a promising technology for early and nondestructive bruise detection.

Differentiation of malignant liver tumors by software-based perfusion quantification with dynamic contrast-enhanced ultrasound (DCEUS).

Assessing the diagnostic value of dynamic contrast-enhanced ultrasound (DCEUS) for the discrimination of different malignant liver lesions. 148 malignant focal liver lesions were assessed prospectively with DCEUS (hepatocellular carcinoma = HCC; cholangiocellular carcinoma = CCC; pancreatic adenocarcinoma = PCA; breast cancer = BC; colorectal cancer = CRC; melanoma = MM). Focal-nodular-hyperplasias (FNH) served as a reference for benign lesions. DCEUS-clips were recorded continuously over three minutes. DCEUS-values were compared between the tumor entities. For better inter-individual comparability, perfusion kinetics were analyzed considering the perfusion characteristics of the surrounding liver parenchyma (Relative Signal Intensity = RSI: lesion-liver tissue/liver tissue) at different points in time. Absolute signal intensity in FNH showed a tendency towards higher values compared with malignant liver lesions [Peak Enhancement(a.u.): FNH 7111.4; HCC 549.9; CCC -6654.3; PCA -7307.9; BC -4562.4; CRC -10672.9; MM -3034.1]. Washout was significantly less in FNH versus PCA and CRC, and more pronounced and earlier in PCA and CRC versus HCC [RSI 30 seconds after PE-lesion(%): FNH +52; PCA -65; CRC -76; HCC -26]. Rise Time, Fall Time and mean-Transit-Time did not differ significantly. DCEUS-values reflect significant differences between malignant liver lesions, especially at peak enhancement and during the washout phases.

First Clinicopathologic Evidence of a Non-PSMA-Related Uptake Mechanism for 68Ga-PSMA-11 in Salivary Glands.

The intense accumulation of prostate-specific membrane antigen (PSMA) radioligands in salivary glands is still not well understood. It is of concern for therapeutic applications of PSMA radioligands, because therapeutic radiation will damage these glands. A better understanding of the uptake mechanism is, therefore, crucial to find solutions to reduce toxicity. The aim of this study was to investigate whether the accumulation of PSMA-targeting radioligands in submandibular glands (SMGs) can be explained with PSMA expression levels using autoradiography (ARG) and immunohistochemistry (IHC). Methods: All patients gave written informed consent for further utility of the biologic material. The SMG of 9 patients, pancreatic tissue of 4 patients, and prostate cancer (PCA) lesions of 9 patients were analyzed. Tissue specimens were analyzed by means of PSMA-IHC (using an anti-PSMA-antibody and an immunoreactivity score system [IRS]) and ARG using 177Lu-PSMA-617 (with quantification of the relative signal intensity compared with a PSMA-positive standard). The SUVmax in salivary glands, pancreas, and PCA tissues were quantified in 60 clinical 68Ga-PSMA-11 PET scans for recurrent disease as well as the 9 primary tumors selected for ARG and IHC. Results: PCA tissue samples revealed a wide range of PSMA staining intensity on IHC (IRS = 70-300) as well as in ARG (1.3%-22% of standard). This variability on PCA tissue could also be observed in 68Ga-PSMA-11 PET (SUVmax, 4.4-16) with a significant correlation between ARG and SUVmax (P < 0.001, R2 = 0.897). On IHC, ARG, and 68Ga-PSMA-11 PET, the pancreatic tissue was negative (IRS = 0, ARG = 0.1% ± 0.05%, SUVmax of 3.1 ± 1.1). The SMG tissue displayed only focal expression of PSMA limited to the intercalated ducts on IHC (IRS = 10-15) and a minimal signal on ARG (1.3% ± 0.9%). In contrast, all SMG showed a high 68Ga-PSMA-11 accumulation on PET scans (SUVmax 23.5 ± 5.2). Conclusion: Our results indicate that the high accumulation of PSMA radioligands in salivary glands does not correspond to high PSMA expression levels determined using ARG and IHC. These findings provide evidence, that the significant accumulation of PSMA radioligands in SMG is not primarily a result of PSMA-mediated uptake.

ГЕОФИЗИЧЕСКИЙ МОНИТОРИНГ ОПАСНЫХ ТЕХНОГЕННЫХ ПРОЯВЛЕНИЙ НА ПОДРАБАТЫВАЕМЫХ ТЕРРИТОРИЯХ

Rock stability estimation tasks on anthropogenic soils require both preliminary survey and on-going real-time monitoring providing alerts on possible cave-in threats. Using VLF monitoring data incorporated into software-hardware geodynamical processes automated surveillance system allows to accomplish that task. Authors describe a unique method, based on Earth’s natural pulsed electro-magnetic field (ENPEMF) recording and make conclusions on the efficiency of the solutions ap-plied for hazardous geodynamic processes monitoring on anthropogenic soils. The principle of the method is to distinguish spatial variations of ENPEMF signal against diurnal oscillations and tech-nogenic signals. Correlation between relative signal intensity and stress-strained state of the rocks is experimentally demonstrated.

Added Value of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Predicting Response to Somatostatin Analogs in Acromegaly Patients.

To investigate the added value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) sequences in predicting somatostatin analog (SSA) responses in patients with acromegaly. This study included 55 active acromegaly patients with macroadenoma. Mean and maximum signal intensities were measured using region of interests in T2-weighted (T2W) and DCE-MRI sequences. Semi-quantitative values indicating relative signal intensity ratios and contrast-enhanced kinetics were obtained. Bivariate and multivariate analyses were used to determine whether the pathological granulation pattern of adenomas (dense versus others) was associated with patients' demographic variables and semi-quantitative MRI parameters. Three parameters formed the logistic model, x2(3)=23.278, p < 0.0001: age (odds ratio [OR]=1.08), hypointensity of adenomas in T2W images (OR=15.45), and high maximum enhancement ratio in the second interval (ER2max) values (OR=2195.74). The overall accuracy of this model was 85.45% with an area under the curve of 0.880. Sensitivity, specificity, positive predictive, and negative predictive values of the model were 68.75%, 92.31%, 78.58%, and 87.8%, respectively. In patients with newly diagnosed acromegaly, the model created based on the relative T2W signal intensity, patient's age, and ER2 < submax parameter from DCE-MRI sequences might be used to more accurately predict SSA responses.

Diffusion weighted cardiovascular magnetic resonance imaging for discriminating acute from non-acute deep venous Thrombus

BackgroundThe importance of discriminating acute from non-acute thrombus is highlighted. The study aims to investigate the feasibility of readout-segmented diffusion weighted (DW) cardiovascular magnetic resonance (CMR) for discrimination of acute from non-acute deep venous thrombus (DVT).MethodsFor this prospective study from December 2015 to December 2017, 85 participants (mean age = 53 years, age range = 34~74) with DVT of lower extremities underwent readout-segmented DW CMR. DVT of ≤14 days were defined as acute (n = 55) and > 14 days as non-acute (n = 30). DVT visualization on b = 0, b = 800, and apparent diffusion coefficient (ADC) images were assessed using a 4-point scale (0~3, poor~excellent). DW CMR parameters were measured using region of interest (ROI). Relative signal intensity (rSI) and ADC were compared between acute and non-acute DVT using a Mann Whitney test. Sensitivity and specificity for ADC and rSI were calculated.ResultsADC maps had higher visualization scores than b = 0 and b = 800 images (2.7 ± 0.5, 2.5 ± 0.6, and 2.4 ± 0.6 respectively, P<0.05). The mean ADC was higher in acute DVT than non-acute DVT (0.56 ± 0.17 × 10− 3 vs. 0.22 ± 0.12 × 10− 3 mm2/s, P<0.001). Using 0.32 × 10− 3 mm2/s as the cutoff, sensitivity and specificity for ADC to discriminate acute from non-acute DVT were 93 and 90% respectively. Sensitivity and specificity were 73 and 60% for rSI on b = 0, and 75 and 63% for rSI on b = 800.ConclusionsReadout segmented diffusion-weighted CMR derived ADC distinguishes acute from non-acute DVT.Trial registrationThis study is retrospectively registered. Trial registration number: HUST-TJH-2015-146.

Predicting response to somatostatin analogues in acromegaly: machine learning-based high-dimensional quantitative texture analysis on T2-weighted MRI.

To investigate the value of machine learning (ML)-based high-dimensional quantitative texture analysis (qTA) on T2-weighted magnetic resonance imaging (MRI) in predicting response to somatostatin analogues (SA) in acromegaly patients with growth hormone (GH)-secreting pituitary macroadenoma, and to compare the qTA with quantitative and qualitative T2-weighted relative signal intensity (rSI) and immunohistochemical evaluation. Forty-seven patients (24 responsive; 23 resistant patients to SA) were eligible for this retrospective study. Coronal T2-weighted images were used for qTA and rSI evaluation. The immunohistochemical evaluation was based on the granulation pattern of the adenomas. Dimension reduction was carried out by reproducibility analysis and wrapper-based algorithm. ML classifiers were k-nearest neighbours (k-NN) and C4.5 algorithm. The reference standard was the biochemical response status. Predictive performance of qTA was compared with those of the quantitative and qualitative rSI and immunohistochemical evaluation. Five hundred thirty-five out of 828 texture features had excellent reproducibility. For the qTA, k-NN correctly classified 85.1% of the macroadenomas regarding response to SAs with an area under the receiver operating characteristic curve (AUC-ROC) of 0.847. The accuracy and AUC-ROC ranges of the other methods were 57.4-70.2% and 0.575-0.704, respectively. Differences in predictive performance between qTA-based classification and the other methods were significant (p < 0.05). The ML-based qTA of T2-weighted MRI is a potential non-invasive tool in predicting response to SAs in patients with acromegaly and GH-secreting pituitary macroadenoma. The method performed better than the qualitative and quantitative rSI and immunohistochemical evaluation. • Machine learning-based texture analysis of T2-weighted MRI can correctly classify response to somatostatin analogues in more than four fifths of the patients. • Machine learning-based texture analysis performs better than qualitative and quantitative evaluation of relative T2 signal intensity and immunohistochemical evaluation. • About one third of the texture features may not be excellently reproducible, indicating that a reliability analysis is necessary before model development.

A highly sensitive method for detecting Cryptosporidium parvum oocysts recovered from source and finished water using RT-PCR directed to Cryspovirus RNA

Sensitive detection of Cryptosporidium oocysts is important because the protozoan can cause clinical infection in humans at extremely low numbers. In the present study, 1.5 × 102, 1.0 × 103, or 1.0 × 104C. parvum oocysts were spiked into 10 l of source or finished water in triplicate followed by recovery using Envirochek HV sampling capsules. One subsample of the recovered oocysts was analyzed by commercial immunofluorescence assay (IFA), while a second subsample was subjected to DNA-RNA extraction, followed by RT-PCR using primers directed to the gene encoding Cryspovirus capsid. IFA analysis of Envirochek filter eluates of finished water detected oocysts at all 3 C. parvum oocyst doses, but only at the 1.0 × 103 and 1.0 × 104 doses in source water. Cryspovirus RT-PCR appeared to offer greater sensitivity than IFA because C. parvum oocysts were detected using this molecular technique in both source and finished water concentrates at all 3 spiking levels. A linear relationship was observed between log oocysts spiking dose and the relative intensity of the Cryspovirus RT-PCR signal for finished water, but not for source water. These data indicate that Cryspovirus RT-PCR is a sensitive method for detecting C. parvum oocysts in source and finished water.

Double-inversion recovery with synthetic magnetic resonance: a pilot study for assessing synovitis of the knee joint compared to contrast-enhanced magnetic resonance imaging.

To investigate the agreement between double-inversion recovery (DIR) with synthetic magnetic resonance imaging (MRI) and T1-weighted contrast-enhanced (CE)-MRI for the assessment of knee synovitis. T1-weighted CE-MRI and synthetic MRI of 30 patients were compared. Synthetic DIR image reconstruction was performed with two inversion times (280-330ms and 2800-2900ms). Subjective image quality, visibility of synovium, detection of synovitis, and total synovitis score in the knee joint were evaluated on both MR images. The relative signal intensity (SI) and relative contrast of synovium, joint effusion, and bone marrow for two imaging were assessed. Differences in data between two imaging were assessed by using Wilcoxon's signed-rank test and chi-square test/Fisher's exact test. Interobserver agreement was expressed as weighted kappa value. Accuracy of synthetic DIR image was calculated by using CE-MRI as reference standard. T1-weighted CE-MRI yielded better image quality than synthetic DIR imaging (p < 0.001). Interobserver agreements for detecting synovitis diagnosis/sum of the synovitis score were moderate to almost perfect (κ = 0.58/0.44, synthetic DIR; κ = 0.83/0.65, T1-weighted CE-MRI). There were no statistical differences in visibility of synovium (p = 0.058-0.190), detection of synovitis (p < 0.001), and relative SI of structures between two imaging (p = 0.086-0.360). Synovium-to-effusion contrast was higher in synthetic DIR (p = 0.003) and synovium-to-bone marrow contrast was higher in CE-MRI (p < 0.001). Synthetic DIR imaging showed a moderate degree of interobserver agreement and good accuracy for detecting synovitis. Though it has limitations, it may play a role in imaging of degenerative joint disease or larger cohort scientific studies where gadolinium application is not feasible. • Synthetic double-inversion recovery (DIR) imaging avoids the use of contrast agent. • There was no significant difference between T1-weighted CE-MRI and synthetic DIR imaging in evaluating presence of synovitis in knee joint. • Synthetic DIR imaging showed moderate degree of interobserver agreement and good accuracy for detecting synovitis compared to CE-MRI, and it may facilitate evaluation of some regions of peripatellar synovitis.

T1 and T2 quantification from standard turbo spin echo images.

To extract longitudinal and transverse (T1 and T2 ) relaxation maps from standard MRI methods. Bloch simulations were used to model relative signal amplitudes from standard turbo spin-echo sequences: proton density weighted, T2 -weighted, and either T2 -weighted fluid attenuated inversion recovery or T1 -weighted images. Simulations over a range of expected parameter values yielded a look-up table of relative signal intensities of these sequences. Weighted images and flip angle maps were acquired in 8 subjects at 3 T using both single and multislice acquisitions. The T1 and T2 maps were fit by comparing the weighted images to the look-up table, given the measured flip angles. Results were compared with inversion recovery and multi-echo spin-echo experiments. A region analysis showed that relaxation maps computed from single-slice proton density, T2 and T1 weighting provided a mean T1 error of 4% in gray matter and 11% in white matter, and a mean T2 error of 3% and 4%, respectively, in comparison to reference measurements. In multislice acquisitions that are optimized to reduce cross-talk and incidental magnetization transfer, the mean T1 error was 7% in gray matter and 1% in white matter, and the mean T2 errors were 3% and 4%, respectively. The best T1 results were achieved using proton density, T2 and T1 weighting rather than the fluid attenuated inversion recovery, although T2 maps were largely unaffected by this choice. Incidental magnetization transfer reduced T1 accuracy in standard interleaved multislice acquisitions. Through exact sequence modeling and separate flip angle measurement, T2 and T1 may be quantified from a turbo spin-echo brain protocol with proton density, T2 , and T1 weighting.