It is important to predict response of esophageal squamous cell carcinoma (ESCC) to neoadjuvant immunochemotherapy for treatment decision-making. This study aimed to explore whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) derived parameters and MR signal intensity can predict the response. About 82 consecutive ESCC patients undergoing pretherapeutic DCE-MRI, T2WI, and T1WI followed by neoadjuvant immunochemotherapy were prospectively enrolled, among which patients from Institution 1 were randomly stratified into training (n = 52) and internal validation (n = 15) cohorts, and those from Institution 2 were assigned to external validation cohort (n = 15). Ktrans, Kep, and Ve of ESCC and their standard deviation (SD) were generated based on DCE-MRI, mean, and SD of MR signal intensity on T1WI and T2WI were also obtained, and coefficient of variation of these parameters were calculated. In training cohort, all parameters were statistically compared between responders and non-responders. Predictive effectiveness of individual parameters with statistical difference, and the parameters based logistic regression models were evaluated using area under the receiver operating characteristic curve (AUC) in three cohorts. Mean and SD of Kep (Kep_Mean and Kep_SD, respectively) and T2WI signal intensity (T2WI_Mean and T2WI_SD, respectively) in responders were higher than in non-responders (all P-values <0.05), among which, Kep_Mean could best predict the responsiveness with AUCs of 0.858, 0.768, and 0.870; and the model (T2WI_Mean + T2WI_SD + Kep_Mean + Kep_SD) demonstrated superior predictive performance (AUCs: 0.928, 0.911, and 0.907) in training, internal and external validation cohorts, respectively. Combination of mean and SD of Kep, and T2WI signal intensity could well predict immunochemotherapy responsiveness of ESCC.

The infrapatellar fat pad mediates environmental exposure for clinical outcomes in knee osteoarthritis.

Reduced harmonic complexity of brain parenchymal cardiovascular pulse waveforms in Alzheimer's disease.

Astrocytic hamartoma is a quite rare disease secondary to tuberous sclerosis and is challenging to identify at the initial ophthalmological examination. The article presents a case report of retinal astrocytic hamartoma secondary to tuberous sclerosis in a 42-year-old male patient. OD ophthalmoscopy revealed a space-occupying, oblong, subretinal, slightly elevated, light yellow lesion of 1.5 disc diameters, with a bumpy surface (resembling a mulberry) at 4–5 o’clock along the inferior nasal vascular arcade. In the left eye, a space-occupying, subretinal, light yellow lesion of 1.5 disc diameters resembling a mulberry was visualized along the superior vascular arcade. A subretinal, flat, gray lesion of about 1.5 disc diameters was observed along the inferior nasal arcade. Magnetic resonance imaging showed multiple lesions (tubers) of altered magnetic resonance signal intensity in the middle cranial fossa, which were typical for tuberous sclerosis. Age of onset, clinical manifestations, and location of tubers in the presented case report are quite consistent with the published data. The presented case report demonstrated challenges of determining etiology of astrocytic hamartoma diagnosed at initial ophthalmological examination.

Studies on gadolinium deposition have recently been reported. The objective of this study was to investigate whether there is an increased magnetic resonance signal intensity (SI) of the dentate nucleus (DCN) and quantification of gadolinium (Gd) brain concentrations by inductively coupled plasma-mass spectrometry (ICP-MS) test in rats who had undergone multiple administrations of gadoxetic acid and gadobutrol. Sprague-Dawley rats (24) were equally divided into three groups. Eight animals per group received 20 intravenous injections of gadoxetic acid (0.15 mmol/kg) and gadobutrol (0.6 mmol/kg) per injection. MRI was performed at 0, 5, and 20 weeks. Subsequently, all animals were euthanized and their brains were dissected for Gd quantification by ICP-MS. ICP-MS revealed higher Gd content in cerebellum tissue after administration of gadoxetic acid compared to gadobutrol (P < 0.05). The mean Gd concentrations in the cerebellum were 0.48 nmol/g gadoxetic acid and 0.26 nmol/g gadobutrol after intravenous administration. No visually evident enhancement was found after administration of gadoxetic acid, gadobutrol, or saline at any time point. The DCN-to-pons SI ratios for gadoxetic acid and gadobutrol were not different from the saline control group (P > 0.05, saline vs. gadoxetic acid and saline vs. gadobutrol, respectively). Our results demonstrated that gadolinium concentrations in the cerebellum after intravenous gadoxetic acid administration were higher than for gadobutrol. Multiple administrations of gadoxetic acid disodium are not associated with increased SI in DCN.

Perilymphatic Signal Changes in Vestibular Schwannoma: A Potential Biomarker of Progressive Hearing Loss?

During the first decades of geologic CO2 storage in saline formations and depleted reservoirs, structural trapping is the most important storage mechanism. The effectiveness of CO2 containment hinges on the assumption that the sealing formation remains water wet in the presence of dense CO2. In this work, multiple 13C and 1H magnetic resonance (MR) methodologies were employed for the first time to evaluate the interactions between supercritical CO2, brine, and the pore surface of a Berea sandstone core plug under reservoir conditions. These studies employed a novel variable field superconducting MR and magnetic resonance imaging (MRI) instrument which permitted sequential 1H and 13C measurements of core plugs at high-pressure and high-temperature. To systematically study the wettability of rock core exposed to supercritical CO2, four experiments were designed including bulk CO2 in a high-pressure vessel, bulk CO2-brine, 13CO2 in dried rock core, and a 13CO2-brine-rock experiment.The measured 13C and 1H MR relaxation times in this work indicate that the Berea sandstone remained strongly water-wet when the brine saturated core plug was exposed to supercritical CO2 under reservoir conditions. For both 13C and 1H, T1 relaxation times provide more reliable wettability evaluation as compared to T2 due to the impact of molecular diffusion through internal magnetic field gradients. One-dimensional (1D) MRI was employed to spatially resolve 13CO2 and brine in the core plug. Two-dimensional (2D) MRI was able to image 13CO2 and brine in a PEEK vessel. The quantities of CO2 and brine in the core plug were determined from the MR signal intensities of 13CO2 and brine.

BACKGROUND: During pathological and forensic autopsies, the bodies of the deceased are examined to identify nonspecific cadaveric changes. These changes include internal hypostases, which are characterized by the redistribution of blood in tissues and organs under the influence of gravity [1, 2]. Such postmortem hypostases reflect the age of death, but they also complicate the differential diagnosis of lifetime pathological processes and lesions with nonspecific cadaveric changes [3, 4]. Postmortem magnetic resonance imaging represents an objective and noninvasive method of investigation, particularly in cases of neonatal death characterized by relative immaturity of organs and tissues. It may therefore prove to be a promising approach to visualize and evaluate cadaveric hypostases [5, 6]. AIM: The aim of this study was to investigate the manifestations of cadaveric hypostases in the liver of deceased neonates, with a focus on the impact of postmortem period duration. This was achieved through the use of postmortem magnetic resonance imaging and morphologic examination. MATERIALS AND METHODS: The study was based on a comprehensive postmortem radiology and pathological anatomical examination of the bodies of 62 newborns and infants who died at the age of 1.5 hours to 49 days. The subjects were selected to exclude those with developmental anomalies and liver diseases. A postmortem magnetic resonance imaging examination was conducted on a 3T Siemens Magnetom Verio apparatus, followed by a subsequent pathological and anatomic autopsy. The T1- and T2-weighted images were evaluated to determine the presence and severity of the magnetic resonance signal intensity gradient line in the ventral (superior) and dorsal (inferior) regions of the liver tissue. Following the autopsy, tissue samples were obtained from the ventral and dorsal regions of the liver, and subsequently subjected to microscopic analysis of hematoxylin and eosin-stained preparations. RESULTS: The results of postmortem magnetic resonance imaging have enabled the establishment of the radiation characteristics and histological changes in liver tissue caused by cadaveric hypostases. The most notable manifestation of cadaveric hypostases in the liver at postmortem magnetic resonance imaging is the change in magnetic resonance signal intensities in the above and below-located regions of the organ, accompanied by the emergence of a signal intensity gradient. This gradient reflects the location of the body after death and varies depending on the duration of the postmortem period. The signal intensity gradient was more frequently observed on T1-weighted images compared to T2-weighted images. Histological examination of liver tissue preparations revealed an increase in the size of sinusoids and a decrease in the area of hepatic beams, which was observed to progress with increasing age at death and was expressed to a greater extent in the lower liver region. These changes are undoubtedly a morphologic substrate of radiation characteristics. CONCLUSIONS: The specific characteristics of cadaveric liver hypostases, as revealed by postmortem magnetic resonance imaging and morphological study, should be taken into account when analyzing the results and determining the links of thanatogenesis of dead newborns.

BackgroundWith increasing studies being published on regenerative endodontic procedures (REPs) as a treatment modality for mature necrotic teeth, the assessment of outcomes following regenerative endodontic procedures has become more challenging and the demand for a better understanding of the regenerated tissues following this treatment is rising. The study aimed to correlate cold, electric pulp testing (EPT), and magnetic resonance imaging (MRI) signal intensity (SI) in mature necrotic teeth treated with regenerative endodontic procedures.MethodologyThis retrospective cohort study included eighteen adult patients who experienced tooth necrosis in mature maxillary anterior teeth recruited from the outpatient clinic, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt from July 2017 until December 2018 with 12 months of follow-up. regenerative endodontic procedures via blood clot were performed. The canals were instrumented by ProTaper Next (PTN) files until final sizes X3 or X5. Biodentine was used as cervical plug material. Pre and post-operative clinical follow-up was done where the patients’ responses to cold and electric pulp testing were given a scoring system and were compared to the normal contralateral tooth. Pre and post-operative magnetic resonance imaging signal intensity of both the involved tooth and its contralateral at the middle and the apical thirds of the root canals were assessed after 3, 6, and 12 months. Data was analyzed using the ANOVA, Friedman and Bonferroni tests. Significance was set at a p-value < 0.05.ResultsAll 18 teeth scored a baseline score of “2” for cold and electric pulp testing. There was a significant difference between scores of the cold test at baseline and 12-month follow-up (p < 0.001). There was a significant difference between scores of the electric pulp testing of baseline and 12-month follow-up (p < 0.001). There was a moderately significant indirect (inverse) correlation between magnetic resonance imaging signal intensity and cold test in both the middle and apical thirds at 12 months. No significant correlations were detected between magnetic resonance imaging signal intensity and electric pulp testingat any of the time intervals (p > 0.05).ConclusionMagnetic resonance imaging is a successful non-invasive method to assess outcomes of regenerative endodontic procedures and correlating it with another reliable method of assessing pulpal responses, cold test, could validate these outcomes.Clinical trial registrationThe study was registered with ClinicalTrials.gov (ID: NCT03804450).

Adipose tissue-derived stem cells (ADSCs) have been shown to improve erectile function in animal models of erectile dysfunction. However, few studies have been carried out using a reliable in vivo imaging method to trace transplanted cells in real time, which is necessary for systematic investigation of cell therapy. The study aims to explore the feasibility of non-invasively monitoring intracavernous injection of ADSCs in rat and miniature pig corpus cavernosum using in vivo magnetic resonance (MR) imaging. Thirty-six male Sprague Dawley rats (10 weeks old) and six healthy, sexually mature male miniature pigs (20 kg weight) were obtained. ADSCs were isolated from paratesticular fat of donor rats and cultured. Then ADSCs were labeled with superparamagnetic iron oxide nanoparticles (SPIONs), a type of MR imaging contrast agent, before transplantation into rats and pigs. After intracavernous injection, all rats and pigs underwent and were analyzed by MR imaging at the day of ADSC transplantation and follow-up at 1, 2 and 4 weeks after transplantation. In addition, penile histological examination was performed on all rats and pigs before (n = 6) and at 1 day (n = 6), 1 week (n = 6), 2 weeks (n = 6) or 4 weeks (n = 12) after ADSC transplantation. SPION-labeled ADSCs demonstrated a strong decreased signal intensity compared with distilled water, unlabeled ADSCs or agarose gel. SPION-labeled ADSCs showed a hypointense signal at all concentrations, and the greatest hypointense signal was observed at the concentration of 1 × 106. MR images of the corpus cavernosum showed a hypointense signal located at the injection site. T2*-weighted signal intensity increased over the course of 1 week after ADSCs transplantation, and demonstrated a similar MR signal with that before ADSCs transplantation. After SPION-labeled ADSC injection, T2*-weighted MR imaging clearly demonstrated a marked hypointense signal in pig corpus cavernosum. The T2*-weighted signal faded over time, similar to the MR imaging results in rats. Obvious acute inflammatory exudation was induced by intracavernous injection, and the T2*-weighted signal intensity of these exudation was higher than that of the injection site. The presence of iron was detected by Prussian blue staining, which demonstrated ADSC retention in rat corpus cavernosum. Lack of cellular infiltrations were demonstrated by H&E staining before and 4 weeks after transplantation, which indicated no negative immune response by rats. Prussian blue staining was positive for iron oxide nanoparticles at 2 weeks after transplantation. SPION-labeled ADSCs showed a clear hypointense signal on T2-weight MRI in vitro and in vivo. The MR signal intensity in the corpus cavernosum of the rats and miniature pigs faded and disappeared over time after ADSC transplantation. These findings suggested that MR imaging could trace transplanted ADSCs in the short term in the corpus cavernosum of animals.

The neutral catalysts [IrCl(H)2(NHC)(substrate)2] or [IrCl(H)2(NHC)(substrate)(sulfoxide)] are used to transfer polarization from para hydrogen (pH2) to 3,5-dichloropyridine and 3,5-dibromopyridine substrates. This is achieved in a rapid, reversible, and low-cost process that relies on ligand exchange within the active catalyst. Notably, the sulfoxide-containing catalyst systems produced NMR signal enhancements between 1 and 2 orders of magnitude larger than its unmodified counterpart. Consequently, this signal amplification by reversible exchange hyperpolarization method can boost the 1H, 13C, and 15N nuclear magnetic resonance (NMR) signal intensities by factors up to 4350, 1550, and 46,600, respectively (14.0, 1.3, and 15.4% polarization). In this paper, NMR and X-ray crystallography are used to map the evolution of catalytically important species and provide mechanistic rational for catalytic efficiency. Furthermore, applications in spontaneous radiofrequency amplification by stimulated emission and NMR reaction monitoring are also shown.

In adamantinomatous craniopharyngiomas, tumor topographical categories, cystic component volume, and magnetic resonance signal intensity may impact prognosis. To identify magnetic resonance imaging (MRI) variables associated with pituitary-hypothalamic axis dysfunction and predictive of outcome in children with cystic adamantinomatous craniopharyngiomas. We evaluated 40 preoperative MRIs of adamantinomatous craniopharyngiomas to classify tumor topography, volume, and signal intensity of the cystic components and peritumoral edema. Volumes and normalized signal intensity minimum values were extracted from coronal T2-weighted images (nT2min). Radiological variables were compared to pituitary-hypothalamic axis dysfunction-related clinical data and surgical outcomes. Adamantinomatous craniopharyngiomas were categorized into five topographic classes (12 patients, sellar-suprasellar; seven patients, pseudo-intraventricular; six patients, strict intraventricular; 14 patients, secondary intraventricular; one patient, not strict intraventricular). All cases exhibited a predominant (30 patients, 80%) or total (10 patients, 20%) cystic tumor component and displayed low nT2min percentage values compared to cerebrospinal fluid (42.3% [interquartile range 28.4-54.6%]). Significant associations between tumor topographic classes and pituitary dysfunction (P<0.001), andbetween peritumoral edema and hypothalamic dysfunction (P<0.001) were found. Considering extent of surgical removal and tumor relapse, volume of the cystic tumor component displayed a positive correlation (P=0.002; r=0.48; P=0.02; r=0.36), while nT2min intensity values exhibited a negative correlation (P=0.01; r= - 0.40; P=0.028; r= - 0.34). Severe hypothalamic-pituitary axis dysfunction is associated with tumors along the pituitary stalk and peritumoral edema. Tumor invasion of the third ventricle, tight adherence to the hypothalamus, larger volumes, and lower nT2min intensity of the tumor cystic component are independent predictors of extent ofadamantinomatous craniopharyngioma excision and recurrence.

Retrospective review. Our goal was to investigate the incidence of cervical degenerative disk disease (DDD) in patients with adolescent idiopathic scoliosis (AIS), before surgical intervention. AIS is often associated with thoracic hypokyphosis and compensatory cervical kyphosis. In adults, cervical kyphosis is associated with DDD. Although cervical kyphosis has been reported in up to 60% AIS patients, the association with cervical DDD has not been reported. A retrospective review was conducted from January 2014 to December 2019 of all consecutive AIS patients. Inclusion criteria were AIS patients over 10 years of age with cervical magnetic resonance imaging and anterior-posterior and lateral spine radiographs within 1 year of each other. Magnetic resonance imaging were reviewed for evidence of cervical DDD. Severity of cervical changes were graded using the Pfirrmann classification and by a quantitative measure of disk degeneration, the magnetic resonance signal intensity ratio. Eighty consecutive patients were included (mean age: 14.1 years, SD=2.5 years). Increasing cervical kyphosis was significantly correlated to decreasing thoracic kyphosis ( r =0.49, P <0.01) and increasing major curve magnitude ( r =0.22, P =0.04). Forty-five patients (56%) had the presence of DDD (grades 2-4) with a mean cervical kyphosis of 11.1° (SD=9.5°, P <0.01). More cervical kyphosis was associated with more severe cervical DDD as graded by Pfirrmann classification level ( P <0.01). Increasing cervical kyphosis was also positively associated with increasing magnetic resonance signal intensity ratio ( P <0.01). Nine patients had ventral cord effacement secondary to DDD with a mean cervical kyphosis of 22.8° (SD=8.6°) compared with 2.6° (SD=11.2°) in those who did not ( P <0.01). Cervical kyphosis was significantly associated with increasing severity of cervical DDD in patients with AIS. Patients with evidence of ventral cord effacement had the largest degree of cervical kyphosis with a mean of 22.8±8.6°. This is the first study to evaluate the association between cervical kyphosis in AIS with cervical DDD.

Early in vivo Radiation Damage Quantification for Pediatric Craniospinal Irradiation Using Longitudinal MRI for Intensity Modulated Proton Therapy

Introduction/Objectives. Osteosarcoma is the most common primary malignant bone tumor in adolescents and young adults, with a tendency to produce variable amounts of osteoid, cartilage, and fibrous matrices. The objective of this study is to differentiate between osteosarcoma subtypes: osteoblastic and chondroblastic according to their magnetic resonance imaging (MRI) signal intensities and X-ray findings. Methods. We performed a retrospective analysis for 21 pathologically proven osteosarcoma subtypes: osteoblastic (n = 14) and chondroblastic (n = 7). Conventional images of the bone of origin, periosteal reactions, lytic and sclerotic features, the presence of calcification, and pathological fractures were investigated with X-rays. We measured the mean region of interest values for each lesion with MRI sequences. Results. Among the osteosarcoma lesions, 57% were localized at the knee. X-ray evaluations of the osteoblastic osteosarcomas revealed pure lytic lesions in 35.7%, and pure sclerotic lesions in 42.9% cases. Chondroblastic osteosarcomas revealed pure lytic lesions in 14.3% and pure sclerotic lesions in 42.9% cases. Due to variable osteoblastic, chondroblastic, and fibroblastic areas and proportions of the ossified matrix, osteosarcoma lesions have a heterogeneous MRI signal. However, no statistically significant value was detected. Conclusion. According to our results, MRI signal characteristics and X-ray findings may not be able to distinguish osteosarcoma subtypes, so prospective studies with larger patient cohorts are needed.

PurposeWith advances in anti-diabetes drugs, increasing numbers of patients have high urinary glucose concentrations, which may alter magnetic resonance (MR) signal intensity. We sought to elucidate the effect of urinary glucose concentration and pH on transverse relaxation and MR signal intensity.Materials and methodsThe transverse relaxation rate (R2) was measured in samples with different glucose concentrations (in vitro) and in the urinary bladder of seven patients with diabetes and nine healthy volunteers (in vivo). The glucose concentration and pH in the in vitro samples and urine were measured. The signal intensity ratio of the bladder to adjacent tissues was obtained on T2-weighted imaging (WI), T1WI, and MR urography (in vivo). To clarify the effect of pH further, the urine of two healthy subjects was adjusted with acid and/or base to obtain various pH values (ex vivo).ResultsR2 increased significantly with high glucose concentrations in the in vitro study. In the in vivo study, high glucose concentration (p < 0.001) and low pH (p = 0.005) were significantly associated with high R2. R2 was higher (p = 0.002) and the signal in maximum-intensity projection images of MR urography was lower (p = 0.005) in patients with diabetes than in healthy subjects. Ex vivo study revealed that a decrease in pH in acid portion resulted in increased R2.ConclusionHigh concentrations of urinary glucose and low pH both enhance transverse relaxation, which, in turn, causes low signal intensity in urinary bladder on long echo time (TE) images, such as MR urography. Radiologists should be aware of this phenomenon when interpreting abnormally low-intensity bladders on long TE images.

The effect of time delay for magnetic resonance contrast-enhanced scan on imaging for small-volume brain metastases

The reported changes in self-diffusion of small molecules during reactions have been attributed to "boosted mobility". We demonstrate the critical role of changing concentrations of paramagnetic ions on nuclear magnetic resonance (NMR) signal intensities, which led to erroneous measurements of diffusion coefficients. We present simple methods to overcome this problem. The use of shuffled gradient amplitudes allows accurate diffusion NMR measurements, even with time-dependent relaxation rates caused by changing concentrations of paramagnetic ions. The addition of a paramagnetic relaxation agent allows accurate determination of both diffusion coefficients and reaction kinetics during a single experiment. We analyze a copper-catalyzed azide-alkyne cycloaddition "click" reaction, for which boosted mobility has been claimed. With our methods, we accurately measure the diffusive behavior of the solvent, starting materials, and product and find no global increase in diffusion coefficients during the reaction. We overcome NMR signal overlap using an alternative reducing agent to improve the accuracy of the diffusion measurements. The alkyne reactant diffuses slower as the reaction proceeds due to binding to the copper catalyst during the catalytic cycle. The formation of this intermediate was confirmed by complementary NMR techniques and density functional theory calculations. Our work calls into question recent claims that molecules actively propel or swim during reactions and establishes that time-resolved diffusion NMR measurements can provide valuable insight into reaction mechanisms.

Effect of Dihydropyridine Enrichment in the Microstructure of the Palisade Layer on the Stability of Fat Nano-emulsions.

Precise correlation between three-dimensional (3D) imaging and histology can aid biomechanical modeling of the breast. We develop a framework to register ex vivo images to histology using a novel cryo-fluorescence tomography (CFT) device. A formalin-fixed cadaveric breast specimen, including chest wall, was subjected to high-resolution magnetic resonance (MR) imaging. The specimen was then frozen and embedded in an optimal cutting temperature (OCT) compound. The OCT block was placed in a CFT device with an overhead camera and 50μm thick slices were successively shaved off the block. After each shaving, the block-face was photographed. At select locations including connective/adipose tissue, muscle, skin, and fibroglandular tissue, 20μm sections were transferred onto cryogenic tape for manual hematoxylin and eosin staining, histological assessment, and image capture. A 3D white-light image was automatically reconstructed from the photographs by aligning fiducial markers embedded in the OCT block. The 3D MR image, 3D white-light image, and photomicrographs were rigidly registered. Target registration errors (TREs) were computed based on 10 pairs of points marked at fibroglandular intersections. The overall MR-histology registration was used to compare the MR intensities at tissue extraction sites with a one-way analysis of variance. The MR image to CFT-captured white-light image registration achieved a mean TRE of 0.73 ± 0.25mm (less than the 1 mm MR slice resolution). The block-face white-light image and block-face photomicrograph registration showed visually indistinguishable alignment of anatomical structures and tissue boundaries. The MR intensities at the four tissue sites identified from histology differed significantly (p<0.01). Each tissue pair, except the skin-connective/adipose tissue pair, also had significantly different MR intensities (p<0.01). Fine sectioning in a highly controlled imaging/sectioning environment enables accurate registration between the MR image and histology. Statistically significant differences in MR signal intensities between histological tissues are indicators for the specificity of correlation between MRI and histology.