Administration Of Contrast Agent Research Articles

Loss of aquaporin-4 impairs cerebrospinal fluid solute clearance through cerebrospinal fluid drainage pathways.

The aquaporin-4 (AQP4) water channel is essential in neurofluid dynamics. AQP4 loss impairs solute exchange between the cerebrospinal fluid (CSF) and interstitial fluid (ISF). However, whether AQP4 expression affects solute clearance from the CSF space to the extracranial space remains unclear. This study aimed to investigate this using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) following the intrathecal administration of gadolinium-based contrast agents (GBCAs) to AQP4 knockout (KO) rats. AQP4 KO rats showed reduced efflux of intrathecal GBCAs to the extracranial spaces through CSF drainage pathways and increased retention of intrathecal GBCAs in the CSF space compared with the controls. These results suggest that AQP4 loss impairs solute clearance from the CSF space to the extracranial spaces via the CSF drainage pathways. This study revealed a close relationship between AQP4 expression and CSF solute clearance, contributing to a better understanding of the function of AQP4 in neurofluid dynamics.

NCMP-01. EARLY RECURRENCE OF GLIOBLASTOMA MULTIFORM INVOLVING MULTIPLE BRAIN REGIONS ASSOCIATED WITH MUTATIONS IN EXON 4 OF ISOCITRATE DEHYDROGENASE 1 COMPLICATED BY GADOLINIUM-INDUCED ACUTE KIDNEY FAILURE: A CASE REPORT

Abstract BACKGROUND Glioblastoma multiform (GBM) remains one of the most aggressive primary brain tumors with high recurrence rates. Case presentation We present a case of a 43-year-old female, Yira, diagnosed with early recurrence of GBM involving multiple brain regions, accompanied by mutations in exon 4 of isocitrate dehydrogenase 1 (IDH1), a marker associated with poor prognosis. Additionally, this case was complicated by gadolinium-induced acute kidney failure on postoperative day 3. The patient initially presented with progressive neurological symptoms, including headache and cognitive decline. Multiplanar multiecho MRI of the brain was performed with IV contrast in orthogonal plane and revealed a moderate sized multilobulated heterogeneously and predominantly peripherally enhancing mass lesion with irregular margins and central non enhancing areas of necrosis arising from the right corona radiata, insular cortex, external capsule, lentiform nucleus, temporal, and frontal white matter with blood products. Perilesional edema was seen. Effacement of sulcal spaces. Right sylvian fissure, compression over right ventricle and midline shift of 8mm toward left side. There was dilatation of the left lateral ventricle with periventricular cerebrospinal fluid ooze. Uncal herniation was right side. On MR spectroscopy large choline, creatinine levels were seen in the lesion with reduced N-acetyl aspartate levels as compared to the normal parenchyma. Findings were suggestive of neoplastic lesion mostly high-grade glioma. Polymerase chain reaction sequencing confirmed missense mutation R132H in exon 4 of isocitrate dehydrogenase 1 gene. Despite maximal safe surgical resection, the patient developed recurrent GBM within three months, with gadolinium-based contrast agent exposure leading to acute kidney injury. CONCLUSION The combination of aggressive tumor behavior and complications from contrast agent administration highlights the challenges in managing recurrent GBM. This case underscores the importance of vigilant monitoring for complications in GBM patients, particularly those with IDH1 mutations, and the need for further research into novel therapeutic strategies.

NIMG-19. DEUTERIUM METABOLIC IMAGING INTERROGATES THE HISTONE H3K27M MUTATION AND PROVIDES AN EARLY READOUT OF RESPONSE TO THERAPY IN DIFFUSE MIDLINE GLIOMAS

Abstract Diffuse midline gliomas (DMGs) are lethal primary brain tumors in children that are driven by recurrent lysine 27 to methionine mutations in histone H3 (H3K27M). Radiation is standard of care and the imipridones ONC201 and ONC206 have emerged as promising therapies for DMG patients. Although magnetic resonance imaging (MRI) is the mainstay for patient management, it does not reliably assess response to therapy. Therefore, the goal of this study was to identify metabolic alterations induced by H3K27M that can be leveraged for non-invasive metabolic imaging of DMGs. Using patient-derived (BT245, SF8628, SF7761, SU-DIPG-6, DIPG7, SU-DIPG-13) and syngeneic (26-B7, 26-C2) models, we show that the H3K27M mutation upregulates glucose metabolism via glycolysis to lactate. Silencing the H3K27M mutation reduces glycolytic capacity and depletes lactate, an effect that is associated with downregulation of rate-limiting glycolytic enzymes and transporters (SLC2A1, HK2, PFKFB3, PGK1, SLC16A3). Deuterium metabolic imaging (DMI) is a novel, clinical stage method of tracing glucose metabolism in vivo. Our studies show that lactate production from [6,6-2H]-glucose is spatially localized to tumor vs. normal brain in mice bearing intracranial BT245, SF8628 or 26-B7 xenografts at clinical magnetic field strength (3T). Lactate production from [6,6’-2H]-glucose is reduced in patient-derived (BT245, SF8628, SF7761) or syngeneic (26-B7) cells treated with radiation, ONC201 or ONC206. Importantly, lactate production is reduced at an early timepoint (5 days) following treatment with ONC206, when changes cannot be detected by MRI, in mice bearing intracranial BT245 or SF8628 xenografts. Collectively, our studies link the H3K27M mutation with elevated glycolysis and identify [6,6’-2H]-glucose as a safe, orally administered contrast agent for visualizing the metabolically active lesion and for imaging early response to therapy in DMGs in vivo. Clinical translation of our studies will provide physicians with a much-needed tool to determine whether DMG patients are responding to standard and experimental therapies under development.

Bioinformatics Analysis and Experimental Validation of Epigallocatechin-3-gallate Against Iopromide-induced Injury in HEK-293 Cells via Anti-oxidative and Anti-inflammation Pathways.

The administration of contrast agents can adversely affect kidney function. Nevertheless, the nephrotoxicity of iopromide in human renal cells, potential therapeutic agents, and the underlying molecular mechanisms have not been thoroughly investigated. The proliferation of HEK-293 kidney cells was assessed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide (MTT) assay. Apoptotic cell death was examined using the TUNEL assay and caspase-3 activity measurements. The impacts and potential pathways of epigallocatechin-3-gallate (EGCG) on iopromide-induced renal damage were analyzed through whole transcriptome sequencing. The redox state was assessed by measuring reactive oxygen species (ROS) production and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Iopromide-induced inhibition of cell proliferation and apoptosis in HEK-293 cells was counteracted by EGCG co-treatment. Pathway analysis revealed that molecules related to antioxidant and anti-inflammatory responses, such as ERK1/2, STAT1, and NF-[Formula: see text]B, were pivotal in the action of EGCG. Iopromide-induced ROS production, decreased DPPH scavenging ability, DNA strand breaks, elevated caspase-3 activity, and reduced cell proliferation were all reversed by EGCG co-treatment in HEK-293 cells. The mechanisms likely involve the attenuation of oxidative stress, inflammatory responses, and apoptosis, with regulation through the ERK1/2, STAT1, and NF-[Formula: see text]B pathways. Further research is necessary to confirm the protective effects of EGCG on renal function, particularly against damage induced by contrast agents like iopromide.

A Rare Case of Pulmonary Vascular Anomaly: MDCT Pulmonary Angiography in Diagnosis of Arteriovenous Malformation and Post-operative Imaging

Objective. To demonstrate the diagnostic algorithm and tactics of a surgical management of patients with pulmonary arteriovenous malformations.Materials and Methods. Based on a patient`s clinical data analysis, further examination tactic was chosen: in the pre and postoperative periods multispiral computed tomography (MSCT) angiopulmonography (on a Canon Aquillion Prime, Japan) was performed before and after intravenous administration of a iodine-containing contrast agent (Ultravist, 370 mg/ ml) at the rate of 1 ml/kg. Brain magnetic resonance tomography was performed on a Signa Voyager, General Electric, China, 1,5 Tl in the pulse sequences T1, T2, T2 FLAIR, DWI, SWAN in three mutually perpendicular planes with a slice thickness of 1-5 mm to examine the neurological complications. Interventional angiopulmonography was implemented by using General Electric Innova IGS530, France, angiographic system before and after endovascular occluder ("AMPLATZER Vascular PLUG 4", USA) and spirals ("2D-Helical-35" 9 mm in diameter and 2,7 mm long (4 spirals) and "Complex–Helical-18" 11 mm in diameter and 17 mm long, USA) placement. A literature review in Russian and English languages for the last 5 years was searched using CyberLeninka, PubMed Central, Elibrary data bases, by keywords: pulmonary arteriovenous malformation, MSCT angiopulmonography, endovascular treatment. The prospective longitudinal study was conducted in compliance with the principles of ethics in accordance with the Helsinki Declaration, and informed voluntary consent was obtained from the patient.Results. According to clinical and instrumental data, the tactics of combined endovascular treatment of a vascular malformation with subsequent postoperative control was collectively chosen. During the curation, an increase in saturation parameters, general wellbeing improvement, decrease in pulmonary pressure parameters, and diminution in the size of the right heart's parts were achieved.Conclusion. Arteriovenous malformations (AVMs) are rare vascular abnormalities that represent a pathological communication between the arterial and venous bed. The fistulous link leads to an abnormal discharge of blood, bypassing the physiological capillary channel. Radiation and interventional visualization methods play the most important diagnostic, and the latest — therapeutic role in management of patients and are able to establish indications for surgical intervention, prevent the occurrence of life-threating complications: abscesses, paradoxical embolism and heart attacks, progressive respiratory and heart failure.

Ultrasonography of the salivary glands in Sjögren's disease: own data analysis

Objective: to investigate feasibility of using ultrasonography (US) to evaluate structural changes of salivary glands (SG) in patients with Sjögren's disease (SD).Material and methods. The study included 159 patients who were examined in V.A. Nasonova Research Institute of Rheumatology from 2016 to 2022 who met V.A. Nasonova Research Institute of Rheumatology 2001, and/or ACR 2012, and/or ACR/EULAR 2016 criteria for SD, and who had not previously received immunosuppressive therapy. All patients underwent a comprehensive classical examination (ophthalmological, dental, immunological) to diagnose SD. Disease activity was determined using ESSDAI index. US of the parotid gland (PG) and submandibular SGs was performed using a GE LOGIQ 9 device, and the images obtained were scored according to the OMERACT SGUS scoring system (SGUS SS).Results and discussion. All SGUS SS scores statistically significantly correlated (p<0.05) with mouth sicca symptoms, enlargement of PG, ESSDAI activity index, presence of lymphohistiocytic infiltrate and focus score in labial SG biopsy, and parenchymatous parotitis according to sialography. No significant correlation was found with the results of sialometry. There was a significant correlation between the changes detected by US and sialography (r=0.422; p=0.001). Considering the data obtained, the consistency of the results of the different examination methods was analyzed. Bland-Altman diagrams were created to reflect the dependence of the differences between the results of US and sialography. At various stages of the comparison, not all data points were within the standardized range. In addition, 5% of the parameters were not within the interval of two standard deviations. The Bland-Altman analysis revealed a systematic discrepancy indicating a low degree of agreement between the two methods for determining structural changes in SG. According to the ROC analysis, sensitivity of ultrasound was 94% and specificity 51%. The area under the curve (AUC) was 0.787 (95% confidence interval 0.700–0.875).Conclusion. SG US and sialography are not interchangeable, but complement each other in the assessment of SG structure. SG US is a safer and non-invasive method of SG examination that does not require contrast agent administration and is likely to play an important role in the dynamic monitoring of patients during the therapy. However, sialography is a more accurate method of diagnostics and assessment of the extent of SG lesions.

Quantitative brain T1 maps derived from T1-weighted MRI acquisitions: a proof-of-concept study.

Longitudinal T1 relaxation time is a key imaging biomarker. In addition, T1 values are modulated by the administration of T1 contrast agents used in patients with tumors and metastases. However, in clinical practice, dedicated T1 mapping sequences are often not included in brain MRI protocols. The aim of this study is to address the absence of dedicated T1 mapping sequences in imaging protocol by deriving T1 maps from standard T1-weighted sequences. A phantom, composed of 144 solutions of paramagnetic agents at different concentrations, was imaged with a three-dimensional (3D) T1-weighed turbo spin-echo (TSE) sequence designed for brain imaging. The relationship between the T1 values and the signal intensities was established using this phantom acquisition. T1 mapping derived from 3D T1-weighted TSE acquisitions in four healthy volunteers and one patient with brain metastases were established and compared to reference T1 mapping technique. The concentration of Gd-based contrast agents in brain metastases were assessed from the derived T1 maps. Based on the phantom acquisition, the relationship between T1 values and signal intensity (SI) was found equal to T1 = 0.35 × SI-1.11 (R2 = 0.97). TSE-derived T1 values measured in white matter and gray matter in healthy volunteers were equal to 0.997 ± 0.096 s and 1.358 ± 0.056 s (mean ± standard deviation), respectively. Mean Gd3+ concentration value in brain metastases was 94.7 ± 30.0 μM. The in vivo results support the relevance of the phantom-based approach: brain T1 maps can be derived from T1-weighted acquisitions. High-resolution brain T1 maps can be generated, and contrast agent concentration can be quantified and imaged in brain metastases using routine 3D T1-weighted TSE acquisitions. Quantitative T1 mapping adds significant value to MRI diagnostics. T1 measurement sequences are rarely included in routine protocols. T1 mapping and concentration of contrast agents can be derived from routine standard scans. The diagnostic value of MRI can be improved without additional scan time.

Deep Learning Virtual Contrast-Enhanced T1 Mapping for Contrast-Free Myocardial Extracellular Volume Assessment.

The acquisition of contrast-enhanced T1 maps to calculate extracellular volume (ECV) requires contrast agent administration and is time consuming. This study investigates generative adversarial networks for contrast-free, virtual extracellular volume (vECV) by generating virtual contrast-enhanced T1 maps. This retrospective study includes 2518 registered native and contrast-enhanced T1 maps from 1000 patients who underwent cardiovascular magnetic resonance at 1.5 Tesla. Recent hematocrit values of 123 patients (hold-out test) and 96 patients from a different institution (external evaluation) allowed for calculation of conventional ECV. A generative adversarial network was trained to generate virtual contrast-enhanced T1 maps from native T1 maps for vECV creation. Mean and SD of the difference per patient (ΔECV) were calculated and compared by permutation of the 2-sided t test with 10 000 resamples. For ECV and vECV, differences in area under the receiver operating characteristic curve (AUC) for discriminating hold-out test patients with normal cardiovascular magnetic resonance versus myocarditis or amyloidosis were tested with Delong's test. ECV and vECV showed a high agreement in patients with myocarditis (ΔECV: hold-out test, 2.0%±1.5%; external evaluation, 1.9%±1.7%) and normal cardiovascular magnetic resonance (ΔECV: hold-out test, 1.9%±1.4%; external evaluation, 1.5%±1.2%), but variations in amyloidosis were higher (ΔECV: hold-out test, 6.2%±6.0%; external evaluation, 15.5%±6.4%). In the hold-out test, ECV and vECV had a comparable AUC for the diagnosis of myocarditis (ECV AUC, 0.77 versus vECV AUC, 0.76; P=0.76) and amyloidosis (ECV AUC, 0.99 versus vECV AUC, 0.96; P=0.52). Generation of vECV on the basis of native T1 maps is feasible. Multicenter training data are required to further enhance generalizability of vECV in amyloidosis.

Electron microscopy evidence of gadolinium toxicity being mediated through cytoplasmic membrane dysregulation.

Past functional toxicogenomic studies have indicated that genes relevant to membrane lipid synthesis are important for tolerance to the lanthanides. Moreover, previously reported imaging of patient's brains following administration of gadolinium-based contrast agents shows gadolinium lining the vessels of the brain. Taken together, these findings suggest the disruption of cytoplasmic membrane integrity as a mechanism by which lanthanides induce cytotoxicity. In the presented work we used scanning transmission electron microscopy and spatially resolved elemental spectroscopy to image the morphology and composition of gadolinium, europium, and samarium precipitates that formed on the outside of yeast cell membranes. In no sample did we find that the lanthanide contaminant had crossed the cell membrane, even in experiments using yeast mutants with disrupted genes for sphingolipid synthesis-the primary lipids found in yeast cytoplasmic membranes. Rather, we evidence that lanthanides are co-located with phosphorus outside the yeast cells. These results lead us to hypothesize that the lanthanides scavenge or otherwise form complexes with phosphorus from the sphingophospholipid head groups in the cellular membrane, thereby compromising the structure or function of the membrane, and gaining the ability to disrupt membrane function without entering the cell.

Prediction of Glioma enhancement pattern using a MRI radiomics-based model.

Contrast-MRI scans carry risks associated with the chemical contrast agents. Accurate prediction of enhancement pattern of gliomas has potential in avoiding contrast agent administration to patients. This study aimed to develop a machine learning radiomics model that can accurately predict enhancement pattern of gliomas based on T2 fluid attenuated inversion recovery images. A total of 385 cases of pathologically-proven glioma were retrospectively collected with preoperative magnetic resonance T2 fluid attenuated inversion recovery images, which were divided into enhancing and non-enhancing groups. Predictive radiomics models based on machine learning with 6 different classifiers were established in the training cohort (n = 201), and tested both in the internal validation cohort (n = 85) and the external validation cohort (n = 99). Receiver-operator characteristic curve was used to assess the predictive performance of these radiomics models. This study demonstrated that the radiomics model comprising of 15 features using the Gaussian process as a classifier had the highest predictive performance in both the training cohort and the internal validation cohort, with the area under the curve being 0.88 and 0.80, respectively. This model showed an area under the curve, sensitivity, specificity, positive predictive value and negative predictive value of 0.81, 0.98, 0.61, 0.82, 0.76 and 0.96, respectively, in the external validation cohort. This study suggests that the T2-FLAIR-based machine learning radiomics model can accurately predict enhancement pattern of glioma.

Evaluation of the Contrast Enhancement Performance of Gadopiclenol for Magnetic Resonance Angiography in Healthy Rabbits and Pigs.

Unexpected accumulations of gadolinium in various organs were reported after the administration of gadolinium-based contrast agents, making desirable to reduce the dose while maintaining equivalent diagnostic performance. The aim of this study was to evaluate the contrast enhancement performance of high relaxivity gadopiclenol compared with gadoterate meglumine in abdominal contrast-enhanced magnetic resonance angiography (CE-MRA). In a first study in healthy rabbits, axial 3D gradient echo sequences were applied at 4.7 T to study arterial enhancement as a function of gadopiclenol dose (0.025, 0.05, 0.075, and 0.1 mmol Gd/kg) or gadoterate meglumine at 0.1 mmol Gd/kg (n = 5-6/group). The increase in signal-to-noise ratio (ΔSNR) in the aorta at the first pass was measured and compared. In a second, crossover study in 6 healthy pigs, abdominal CE-MRA sequences were acquired at 3 T with gadopiclenol at 0.05 mmol Gd/kg or gadoterate meglumine at 0.1 mmol Gd/kg at a 1-week interval. Quantitatively on the maximum intensity projection (MIP) images, the mean MIP SNR within the aorta of both groups was compared. Qualitatively, a blinded comparison of the angiograms was performed by an experienced radiologist to determine the preferred contrast agent. In the rabbit, ∆SNR is linearly correlated with the gadopiclenol dose ( P = 0.0010). Compared with gadoterate meglumine 0.1 mmol Gd/kg, an increase in the ∆SNR is observed after 0.05, 0.075, and 0.1 mmol Gd/kg of gadopiclenol (+63% P = 0.0731, +78% P = 0.0081, and +72% P = 0.0773, respectively), whereas at 0.025 mmol Gd/kg, ∆SNR is in the same range as with gadoterate meglumine 0.1 mmol Gd/kg (+15% P > 0.9999). In pigs, contrast enhancement after gadopiclenol at 0.05 mmol/kg is +22% superior to MIP SNR after gadoterate meglumine at 0.1 mmol Gd/kg ( P = 0.3095). Qualitatively, a preference was shown for gadopiclenol images (3/6) over the gadoterate meglumine examinations (1/6), with no preference being shown for the remainder (2/6). First-pass CE-MRA is feasible with gadopiclenol at 0.05 mmol Gd/kg with at least the same arterial signal enhancement and image quality as gadoterate meglumine at 0.1 mmol Gd/kg.

Brain Metastases in Differentiated Thyroid Cancer: Clinical Presentation, Diagnosis, and Management.

Background: Brain metastases (BM) are the most common intracranial neoplasms in adults and are a significant cause of morbidity and mortality. The brain is an unusual site for distant metastases of thyroid cancer; indeed, the most common sites are lungs and bones. In this narrative review, we discuss about the clinical characteristics, diagnosis, and treatment options for patients with BM from differentiated thyroid cancer (DTC). Summary: BM can be discovered before initial therapy due to symptoms, but in most patients, BM is diagnosed during follow-up because of imaging performed before starting tyrosine kinase inhibitors (TKI) or due to the onset of neurological symptoms. Older male patients with follicular thyroid cancer (FTC), poorly differentiated thyroid cancer (PDTC), and distant metastases may have an increased risk of developing BM. The gold standard for detection of BM is magnetic resonance imaging with contrast agent administration, which is superior to contrast-enhanced computed tomography. The treatment strategies for patients with BM from DTC remain controversial. Patients with poor performance status are candidates for palliative and supportive care. Neurosurgery is usually reserved for cases where symptoms persist despite medical treatment, especially in patients with favorable prognostic factors and larger lesions. It should also be considered for patients with a single BM in a surgically accessible location, particularly if the primary disease is controlled without other systemic metastases. Additionally, stereotactic radiosurgery (SRS) may be the preferred option for treating small lesions, especially those in inaccessible areas of the brain or when surgery is not advisable. Whole brain radiotherapy is less frequently used in treating these patients due to its potential side effects and the debated effectiveness. Therefore, it is typically reserved for cases involving multiple BM that are too large for SRS. TKIs are effective in patients with progressive radioiodine-refractory thyroid cancer and multiple metastases. Conclusions: Although routine screening for BM is not recommended, older male patients with FTC or PDTC and distant metastases may be at higher risk and should be carefully evaluated for BM. According to current data, patients who are suitable for neurosurgery seem to have the highest survival benefit, while SRS may be appropriate for selected patient.

Detection of synovial inflammation in the sacroiliac joint space through intravoxel incoherent motion imaging: an alternative to contrast agents.

We investigated the diagnostic accuracy of simplified intravoxel incoherent motion (IVIM) imaging for detecting synovial inflammation in the sacroiliac joint (SIJ) in a population with active sacroiliitis. In accordance with the Assessment of Spondyloarthritis International Society criteria, 86 SIJs of 46 patients with active sacroiliitis were included in this retrospective study conducted between November 2020 and January 2022. Based on T1-weighted post-gadolinium images, the SIJs were divided into two groups: synovial inflammation positive (SIP) (n = 28) and synovial inflammation negative (SIN) (n = 58). Synovial areas in the SIJ space were independently and blindly reviewed for the presence of inflammation by two radiologists with differing levels of expertise in radiology. Using four b values, apparent diffusion coefficient (ADC)= ADC (0, 800) and the simplified 3T IVIM method parameters true diffusion coefficient (D1)= ADC (50, 800), D= ADC (400, 800), f1= f (0, 50, 800), f2= f (0, 400, 800), pseudodiffusion coefficient (D*)= D* (0, 50, 400, 800), ADClow = ADC (0, 50), and ADCdiff= ADClow - D were generated voxel by voxel for each patient. The IVIM and ADC parameters at the SIN and SIP joints were compared. The D parameter was significantly increased in SIP areas (1.23 ± 0.34 × 10-3 mm2/s) compared with SIN areas (1.02 ± 0.16 × 10-3 mm2/s) (P = 0.004). Conversely, the D* parameter was significantly decreased in SIP areas (21.78 ± 3.77 × 10-3 mm2/s) compared with SIN areas (16.19 ± 4.58 × 10-3 mm2/s) (P < 0.001). When the optimal cut-off value of 1.11 × 10-3 mm2/s was selected, the sensitivity for the D value was 71% and the specificity was 72% [area under the curve (AUC): 0.716)]. When the optimal cut-off value of 21.06 × 10-3 mm2/s was selected, the sensitivity for the D* value was 78.6%, and the specificity was 79.3% (AUC: 0.829). The interclass correlation coefficient was excellent for f1, f2 D*, D, and ADCdiff, good for ADClow and D1, but reasonable for ADC. The presence of synovial inflammation in the SIJ can be evaluated with high sensitivity and specificity using only four b values through the simplified IVIM method without the need for a contrast agent. IVIM imaging is a technique that allows us to gain insights into tissue perfusion without the administration of contrast agents, utilizing diffusion-weighted images. In this study, for the first time, we demonstrated the potential of detecting synovial inflammation in the SIJ using IVIM, specifically through the pseudodiffusion (D*) parameter, without the need for contrast agents.

Deposition of Gadolinium in the Central and Peripheral Nervous Systems and Its Effects on Sensory, Cognitive, and Athletic Implications after Multiple Injections of Gadolinium-Based Contrast Agents in Rats.

After repeat administration of gadolinium-based contrast agents (GBCAs), the association between gadolinium retention in the central and peripheral nervous systems and the main manifestations of myelopathy and progressive neurologic symptoms remains unclear. We investigated the effects of the repeat administration of GBCAs on gadolinium retention in the central and peripheral nervous systems and the sensory, cognitive, and athletic implications. Forty-eight male Wistar rats (6 weeks of age) were randomly divided into 4 experimental groups (12 rats in each group): the gadodiamide group (linear and nonionic GBCAs), the gadopentetate dimeglumine group (linear and ionic GBCAs), the gadoterate meglumine group (macrocyclic and ionic GBCAs), and the control group (0.9% saline solution). The brains of the rats were scanned using 9.4T MRI. Sensory behavioral tests were performed to assess the effect of GBCAs on pain sensitivity function. Gadolinium deposition in the brain, spinal cord, and peripheral nerves was determined by inductively coupled plasma mass-spectrometry. Transmission electron microscopy was used to observe the microscopic distribution of gadolinium after deposition in the spinal cord. The histopathologic features in the spinal cord were analyzed by H&E staining, Nissl staining, glial fibrillary acidic protein staining, and neuron-specific enolase staining after administration of GBCAs. All GBCAs resulted in gadolinium deposition in the central and peripheral nerve tissues, with the highest deposition in the sciatic nerve tissue (mean, 62.86 [SD, 12.56] nmol/g). Decreased muscle power, impairment of spatial cognitive function power, and pain hypersensitivity to thermal and mechanical stimuli were observed after exposure to gadodiamide. At the spinal cord, transmission electron microscopy found that the region of gadolinium depositions had a spheric structure similar to "sea urchins" and was mainly located near the vascular basement membrane. Multiple injections of GBCAs caused gadolinium deposition in the brain, spinal cord, and peripheral nerves, especially in the spinal cords of the gadodiamide group. Gadodiamide led to pain hypersensitivity and decreased muscle power and cognitive ability. For the patients who are hypersensitive to pain and need multiple MRI examinations, we recommend using macrocyclic GBCAs and the lowest dose possible.

Comparative Study of Diluted Hydrogen Peroxide and Sulfur Hexafluoride in the Contrast-Enhanced Ultrasound Assessment of Anal Fistulas.

Endoanal ultrasound for the diagnosis of anal fistulas requires the injection of hydrogen peroxide, but it is often uncomfortable for the patient and possesses potential complications. Novel ultrasound contrast is currently available. We aimed to assess the efficacy and safety of sulfur hexafluoride as an ultrasound contrast agent for the diagnosis of perianal fistula by comparing it with those of 50% diluted hydrogen peroxide. Double-blind superiority study with 4 consecutive visits to perform an ultrasound without contrast, a hydrogen peroxide-enhanced ultrasound, a sulfur hexafluoride-enhanced ultrasound and a rectal exploration in the operating room (the gold standard). The ultrasound images were independently reviewed by three expert surgeon sonographers. This study was conducted at a single university hospital. Data from 176 patients were evaluated. Demographic and exploratory data and the ultrasound findings related to the location of the internal fistula orifice, description of the primary and secondary tracts, and presence of cavities and sphincter defects were analyzed. The complications occurring before and after the contrast agent administration and the presence of pain measured using a score were considered. Eighty-eight patients were included (men: 71.5%; mean age: 48.3 years).62.5% had a complex type and 83.7% had a transsphincteric type. Sulfur hexafluoride-enhanced ultrasounds demonstrated a higher interobserver agreement in determining the secondary tracts (κ= 0.604) and anal fistula height (κ=0.604) compared with other methods. Both hydrogen peroxide-enhanced ultrasound (90.91%) and sulfur hexafluoride-enhanced ultrasound (89.77%) detected the internal orifice more frequently than ultrasounds without contrast (62.5%) (p < 0.001),with no differences between contrast agents (p = 0.810). Sulfur hexafluoride-enhanced ultrasound were less painful than peroxide-enhanced ultrasound (p < 0.001). Most of the patients had transsphincteric anal fistulas. Sulfur hexafluoride proved comparable to hydrogen peroxide in evaluating fistulous tracts and identifying the internal orifice and additionally reduced significantly pain and discomfort. Furthermore, demonstrated a higher interobserver agreement in determining the secondary tracts and anal fistula height compared with other methods. See Video Abstract.

Segmentation Guided Crossing Dual Decoding Generative Adversarial Network for Synthesizing Contrast-Enhanced Computed Tomography Images.

Although contrast-enhanced computed tomography (CE-CT) images significantly improve the accuracy of diagnosing focal liver lesions (FLLs), the administration of contrast agents imposes a considerable physical burden on patients. The utilization of generative models to synthesize CE-CT images from non-contrasted CT images offers a promising solution. However, existing image synthesis models tend to overlook the importance of critical regions, inevitably reducing their effectiveness in downstream tasks. To overcome this challenge, we propose an innovative CE-CT image synthesis model called Segmentation Guided Crossing Dual Decoding Generative Adversarial Network (SGCDD-GAN). Specifically, the SGCDD-GAN involves a crossing dual decoding generator including an attention decoder and an improved transformation decoder. The attention decoder is designed to highlight some critical regions within the abdominal cavity, while the improved transformation decoder is responsible for synthesizing CE-CT images. These two decoders are interconnected using a crossing technique to enhance each other's capabilities. Furthermore, we employ a multi-task learning strategy to guide the generator to focus more on the lesion area. To evaluate the performance of proposed SGCDD-GAN, we test it on an in-house CE-CT dataset. In both CE-CT image synthesis tasks-namely, synthesizing ART images and synthesizing PV images-the proposed SGCDD-GAN demonstrates superior performance metrics across the entire image and liver region, including SSIM, PSNR, MSE, and PCC scores. Furthermore, CE-CT images synthetized from our SGCDD-GAN achieve remarkable accuracy rates of 82.68%, 94.11%, and 94.11% in a deep learning-based FLLs classification task, along with a pilot assessment conducted by two radiologists.

Can cereal-based oral contrast agents-assisted ultrasound become an alternative to non-contrast magnetic resonance imaging (MRI) in radiological follow-up for pancreatic cystic lesions?

Pancreatic cystic lesions (PCLs) are recommended to be examined by magnetic resonance imaging (MRI), yet MRI still has limitations, such as high costs, the risk of triggering claustrophobia, and relatively low availability compared with ultrasound. Oral contrast agents-assisted ultrasound has been used to examine the gallbladder and stomach, but whether oral contrast agents could improve the accuracy of transabdominal ultrasound (TAUS) for PCLs and could be a potential alternative to non-contrast MRI for PCL follow-up has not been studied. This study aimed to explore the value of cereal-based oral contrast agents in improving the accuracy of PCLs during TAUS. This is a prospective cohort study. Patients with PCL who were admitted to our center between January 2023 and January 2024 were enrolled, and TAUS was performed before and after taking cereal-based oral contrast agents. The imaging quality of the PCL was measured by structural visualization scores. The structural visualization scores of oral contrast agent-assisted ultrasound and non-contrast MRI were also compared. A total of 27 patients with PCLs were enrolled, and 30 PCLs were detected. The sonolucency of the PCL improved after oral contrast agent administration. Before taking the agent, only 30% of patients had satisfactory sonolucency; after taking the oral contrast agent, the corresponding proportion reached 80% (P=0.002). The structural visualization score of the PCL determined by oral contrast agent-assisted TAUS was higher than that determined without the aid of an agent [1 (0-6) vs. 1 (0-3), P=0.001], which was mainly reflected in the increase in the number of visible septa after taking the agent. No significant difference was detected between the structural visualization score of the PCL examined by oral contrast agent-assisted TAUS and that examined by non-contrast MRI and the correlation between the 2 types of scores were satisfactory [1 (0-6) vs. 2 (0-7), P=0.070, Spearman correlation factor r=0.880]. This study used a structured scoring system to confirm that cereal-based oral contrast agents could improve the ultrasound quality of PCLs, and the correlation between the quality of oral contrast agent-assisted ultrasound and non-contrast MRI findings on PCLs was satisfactory. Further research to improve visualization of PCLs on TAUS using oral contrast agents could result in TAUS being a potential alternative to MRI in the follow-up of PCLs in resource-limited situations.

Sodium selenite attenuates inflammatory response and oxidative stress injury by regulating the Nrf2/ARE pathway in contrast-induced acute kidney injury in rats

BackgroundContrast-induced acute kidney injury (CI-AKI) is an acute renal complication that occurs after intravascular contrast agent administration. Sodium selenite (SS) is an inorganic source of Se and has potent antioxidant properties. This study intends to examine its anti-inflammatory and antioxidant effects in CI-AKI.MethodsA rat CI-AKI model was established with the pretreatment of SS (0.35 mg/kg). Hematoxylin-eosin staining was employed for histopathological analysis of rat kidney specimens. Biochemical analysis was conducted for renal function detection. Tissue levels of oxidative stress-related markers were estimated. Reverse transcription-quantitative polymerase chain reaction revealed the mRNA levels of proinflammatory cytokines. Western blotting showed the Nrf2 signaling-related protein expression in the rat kidney.ResultsSS administration alleviated the renal pathological changes and reduced the serum levels of serum creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin, cystatin C, and urinary level of kidney injury molecule-1 in CI-AKI rats. SS attenuated oxidative stress and inflammatory response in CI-AKI rat kidney tissues. SS activated the Nrf2 signaling transduction in the renal tissues of rats with CI-AKI.ConclusionSS ameliorates CI-AKI in rats by reducing oxidative stress and inflammation via the Nrf2 signaling.

Optimizing pseudo-spiral sampling for abdominal DCE MRI using a digital anthropomorphic phantom.

For reliable DCE MRI parameter estimation, k-space undersampling is essential to meet resolution, coverage, and signal-to-noise requirements. Pseudo-spiral (PS) sampling achieves this by sampling k-space on a Cartesian grid following a spiral trajectory. The goal was to optimize PS k-space sampling patterns for abdomin al DCE MRI. The optimal PS k-space sampling pattern was determined using an anthropomorphic digital phantom. Contrast agent inflow was simulated in the liver, spleen, pancreas, and pancreatic ductal adenocarcinoma (PDAC). A total of 704 variable sampling and reconstruction approaches were created using three algorithms using different parametrizations to control sampling density, halfscan and compressed sensing regularization. The sampling patterns were evaluated based on image quality scores and the accuracy and precision of the DCE pharmacokinetic parameters. The best and worst strategies were assessed in vivo in five healthy volunteers without contrast agent administration. The best strategy was tested in a DCE scan of a PDAC patient. The best PS reconstruction was found to be PS-diffuse based, with quadratic distribution of readouts on a spiral, without random shuffling, halfscan factor of 0.8, and total variation regularization of 0.05 in the spatial and temporal domains. The best scoring strategy showed sharper images with less prominent artifacts in healthy volunteers compared to the worst strategy. Our suggested DCE sampling strategy also showed high quality DCE images in the PDAC patient. Using an anthropomorphic digital phantom, we identified an optimal PS sampling strategy for abdominal DCE MRI, and demonstrated feasibility in a PDAC patient.

Treatment response assessment of acute pyelonephritis: A multi-reader DWI-based MRI approach

PurposeTo evaluate the diagnostic accuracy of a structured reporting score (SRS) in treatment response assessment for acute pyelonephritis (APN) using a diffusion-weighted imaging (DWI) -based MRI approach. Additionally, we explored the influence of reader experience on the interpretation of SRS and DWI, including lesion conspicuity and measurements of Apparent Diffusion Coefficient (ADC) maps. MethodsFollow-up DWI-based MRIs of 36 patients treated for APN between September 2021 and June 2023 were retrospectively reviewed by three readers. Follow-up blood inflammatory markers were used as reference standard. Treatment response was assessed using a structured reporting score (SRS). Each reader assigned a score from 1 to 3 to the "conspicuity" of the residual disease on DWI. Quantitative ADC measurements were compared with the Mann-Whitney U test. Descriptive statistics and Intraclass Correlation Coefficient (ICC) were calculated. ResultsThe diagnostic accuracy of SRS was 80.6 %, 76.9 %, and 72.2 % for the Reader 1, 2, and 3 respectively. ICC decreased from 0.82 (Reader 1 and 2), to 0.68 when considering all readers. The average conspicuity varied between 2.3 and 2.7. ADC values were significantly higher in complete responders for Reader 1 and 2 (153.5-154.5 vs 107.7-116.2, p < 0.001). The ICC was good (0.89) for Reader 1 and 2 and moderate (0.60) when considering all readers. ConclusionsTreatment response of pyelonephritis can be accurately assessed by a DWI-based MRI, potentially avoiding unnecessary contrast agent administration and radiation exposure. SRS and DWI analysis showed a good inter-observer agreement but a certain learning curve may be necessary for less expert readers.