Intravenous Injection Of Contrast Agent Research Articles

The Current Role of Contrast-Enhanced Ultrasound (CEUS) in the Diagnosis and Staging of Bladder Cancer: A Review of the Available Literature.

Contrast-enhanced ultrasound (CEUS) is an advanced imaging technique that integrates conventional US with the intravenous injection of specific US contrast agents (UCAs), combining the non-invasiveness of US with the higher accuracy of contrast-enhanced imaging. In contrast with magnetic resonance imaging (MRI), computed tomography (CT) and cystoscopy, CEUS has few contraindications, and UCAs are non-nephrotoxic agents that can be safely used in patients with kidney failure. CEUS is a well-established method for the detection of liver lesions and for echocardiography, and its indications are expanding. The updated 2018 WFUMB-EFSUMB guidelines have added the urinary bladder under non-hepatic applications of CEUS. The technique is able to distinguish between benign tissue, such as clots or hematoma, and malignant lesions by perfusing the mass with contrast agent. Thanks to the different perfusion rates of the various layers of the bladder wall, CEUS is also able to predict tumor invasion depth and stage. Despite that, current urological guidelines do not include CEUS as a plausible imaging technique for bladder urothelial carcinoma. The main reason for this omission might be the presence of scarce randomized evidence and the absence of large validated series. In this review, we describe the rationale behind the use of CEUS in bladder cancer and the added value of this imaging technique in the detection and staging of bladder lesions. In addition, we researched the available literature on the topic and then described the results of randomized clinical trials and a meta-analysis investigating the accuracy of CEUS in bladder cancer diagnosis and staging. The reported studies show that CEUS is a highly accurate diagnostic and staging tool for BC, reaching levels of specificity and sensitivity in differentiating between Ta-T1, or low-grade BC, and T2, or high-grade BC, that are comparable to those shown by the reference standard methods. Nonetheless, several limitations were found and are highlighted in this review. The aim of this study is to further validate and promote the use of CEUS as a quick, economic and effective diagnostic tool for this high-impact disease.

Effects of Intravenous Infusion of Iodine Contrast Media on the Tracheal Diameter and Lung Volume Measured with Deep Learning-Based Algorithm

This study aimed to investigate the effects of intravenous injection of iodine contrast agent on the tracheal diameter and lung volume. In this retrospective study, a total of 221 patients (71.1 ± 12.4 years, 174 males) who underwent vascular dynamic CT examination including chest were included. Unenhanced, arterial phase, and delayed-phase images were scanned. The tracheal luminal diameters at the level of the thoracic inlet and both lung volumes were evaluated by a radiologist using a commercial software, which allows automatic airway and lung segmentation. The tracheal diameter and both lung volumes were compared between the unenhanced vs. arterial and delayed phase using a paired t-test. The Bonferroni correction was performed for multiple group comparisons. The tracheal diameter in the arterial phase (18.6 ± 2.4 mm) was statistically significantly smaller than those in the unenhanced CT (19.1 ± 2.5 mm) (p < 0.001). No statistically significant difference was found in the tracheal diameter between the delayed phase (19.0 ± 2.4 mm) and unenhanced CT (p = 0.077). Both lung volumes in the arterial phase were 4131 ± 1051 mL which was significantly smaller than those in the unenhanced CT (4332 ± 1076 mL) (p < 0.001). No statistically significant difference was found in both lung volumes between the delayed phase (4284 ± 1054 mL) and unenhanced CT (p = 0.068). In conclusion, intravenous infusion of iodine contrast agent transiently decreased the tracheal diameter and both lung volumes.

Evaluation of tumor microvasculature with 3D ultrasound localization microscopy based on 2D matrix array.

Evaluation of tumor microvascular morphology is of great significance in tumor diagnosis, therapeutic effect prediction, and surgical planning. Recently, two-dimensional ultrasound localization microscopy (2DULM) has demonstrated its superiority in the field of microvascular imaging. However, it suffers from planar dependence and is unintuitive. We propose a novel three-dimensional ultrasound localization microscopy (3DULM) to avoid these limitations. We investigated 3DULM based on a 2D array for tumor microvascular imaging. After intravenous injection of contrast agents, all elements of the 2D array transmit and receive signals to ensure a high and stable frame rate. Microbubble signal extraction, filtering, positioning, tracking, and other processing were used to obtain a 3D vascular map, flow velocity, and flow direction. To verify the effectiveness of 3DULM, it was validated on double helix tubes and rabbit VX2 tumors. Cisplatin was used to verify the ability of 3DULM to detect microvascular changes during tumor treatment. In vitro, the sizes measured by 3DULM at 3mm and 13mm were 178 and 182 , respectively. In the rabbit tumors, we acquired 9000 volumes to reveal vessels about 30 in diameter, which surpasses the diffraction limit of ultrasound in traditional ultrasound imaging, and the results matched with micro-angiography. In addition, there were significant changes in vascular density and curvature between the treatment and control groups. The effectiveness of 3DULM was verified in vitro and in vivo. Hence, 3DULM may have potential applications in tumor diagnosis, tumor treatment evaluation, surgical protocol guidance, and cardiovascular disease. 3D ultrasound localization microscopy is highly sensitive to microvascular changes; thus, it has clinical potential for tumor diagnosis and treatment evaluation. • 3D ultrasound localization microscopy is demonstrated on double helix tubes and rabbit VX2 tumors. • 3D ultrasound localization microscopy can reveal vessels about 30 in diameter-far smaller than traditional ultrasound. • This form of imaging has potential applications in tumor diagnosis, tumor treatment evaluation, surgical protocol guidance, and cardiovascular disease.

Endolymphatic hydrops asymmetry distinguishes patients with Meniere's disease from normal controls with high sensitivity and specificity.

Many endolymphatic hydrops (EH) MRI studies in the literature do not include a normal control group. Consequently, it remains unclear which outcome measure in EH MRI can most effectively distinguish between MD patients and normal controls. Gadolinium-enhanced EH imaging was performed to quantitatively evaluate the extents of hydrops in MD patients and age-/sex-matched normal controls. Four hours after intravenous injection of contrast agent, MRI was performed using a 3-T MR platform fitted with a 32-channel phased-array coil receptor. MR images (10-15 slices) covering an inner ear were 3D-stacked. Analyses of all images that included the vestibule or the cochlea yielded the volumes (in μL) of the endolymphatic and perilymphatic spaces. For the vestibule, they were significantly greater EH% in ipsilateral (52.4 ± 12.5) than in contralateral MD ears (40.4 ± 8.5, p = 0.001) and in ipsilateral MD ears than in control ears (42.4 ± 13.7, p = 0.025). For the cochlea, the values were slightly higher EH% in ipsilateral MD ears (49.7 ± 10.4, p = 0.061) but did not significantly differ from contralateral (41.3 ± 12.6) or control ears (39.6 ± 18.9, p = 0.858). In the MD group, the EH asymmetries were 12.0 ± 10.2% (vestibule) and 8.4 ± 8.6% (cochlea), significantly larger than those of controls. Compared to conventional semiquantitative grading or quantitative EH% analysis, EH asymmetry may better distinguish MD patients from normal controls. Quantitative hydrops volumetric analysis yields clinically relevant information on inner ear function.

Influence of Contrast Materials on Dose Accuracy of MR-Linac in Patients with SBRT Liver Cancer

Objective: Intravenous injection of contrast agent during CT scanning can improve the accuracy of target area contouring, however the contrast agent will cause dose bias due to the high relative electron density. This study aims to explore the influence of contrast agent on the accuracy of dose calculation of the planning system during SBRT based on MRI-Linac for liver cancer treatment. Methods: In this study, 20 patients undergoing stereotactic body radiation therapy (SBRT) for liver cancer were selected, and their complete unenhanced CT, contrast-enhanced CT, and corresponding structures were imported into Monaco V.5.4. The target and organs at risk (OARs) in the unenhanced CT and contrast-enhanced CT were additionally contoured according to the target contouring guidelines and OARs were ranked. The average relative electron densities of OARs (lung, spinal cord, heart, rib, etc.) were calculated with Monaco TPS. The reference plan is based on unenhanced CT for plan calculation (plan1). To compare the dosimetry errors caused by the synthetic CT, the average relative electron density of all structures in unenhanced CT was forced and the plans were recalculated (plan2). To investigate dosimetric differences caused by the changes of relative electron density due to the contrast agent, the average relative electron density of all structures in contrast-enhanced CT was forced and the plans were recalculated(plan3). The dosimetric differences in groups A (plan 1 and plan2), B (plan 1 and plan3), and C (plan2 and plan3) were compared, respectively. There were not significant difference between three groups in the affected lung, heart, liver, blood, all within 3%. However, differences were significantly different in the group B. The maximum deviation of spinal cord Dmax reached 4.78%. In addition, the deviation of the dose parameters in the target area was small, except that the maximum deviation of the CI value in group B was 3.23%. For SBRT planning of liver cancer based on magnetic resonance accelerator, synthetic CT has little influence on the calculation of planned dose. The dose difference caused by contrast materials is also relatively small, although the deviation of the CI value of the target area exceeds 3%, which is also within the clinical acceptance range. However, the deviation of the maximum value of the spinal cord is relatively large, exceeding the clinically acceptable range. Therefore, when optimizing the SBRT plan for liver cancer, attention should be paid to important organs such as the spinal cord, and should be avoided as far as possible when setting the fields.

Role of abbreviated non-contrast-enhanced MR-enterography in the evaluation of Crohn's disease activity and complications as an alternative for full protocol contrast-enhanced study: A systematic review and meta-analysis.

Crohn's disease (CD) is a chronic disorder that often starts at a young age and involves periods of remission and relapse. Prompt diagnosis of relapses through screening is crucial due to the potential morbid complications of untreated active inflammation. Magnetic resonance enterography (MRE) is a noninvasive technique to screen for active inflammation. The standard protocol involves intravenous injection of contrast agents with potential side effects. Some abbreviated non-contrast-enhanced MRE protocols are proposed as alternatives for conventional MRE to identify active inflammation. Currently, there is controversy regarding the applicability and accuracy of these protocols. This study aims to describe and compare these protocols and evaluate their accuracy in detecting active inflammation and CD complications. Results from a systematic search of three databases in August 2022 were queried and screened by abstract and full text. Eligible studies were qualitatively and quantitatively analyzed by diagnostic test accuracy meta-analysis. 59 studies entered the systematic review, and 37 were eligible for meta-analysis. Diffusion-weighted imaging (DWI) and fast T2-weighted (T2w) sequences were most frequently used in abbreviated protocols and showed non-inferior accuracy compared to the full protocol in detecting active inflammation. ADC and qualitative DWI had pooled sensitivity of 90% (CI: 82-95%) and 89% (CI:82-93%) and pooled specificity of 94% (CI: 88-97%) and 89% (CI: 79-94%), respectively for detecting active inflammation. Moreover, T2w and combined T2w+DWI sequences had pooled sensitivity of 80% (CI: 64-90%) and 76% (CI: 61-86%) and pooled specificity of 90% (CI: 80-95%) and 87% (CI: 74 - 94%), respectively. Unenhanced protocols show relatively poor diagnostic accuracy in detecting penetrating complications of CD. Magnetization transfer imaging (MTI) has demonstrated excellent accuracy in detecting fibrosis. High heterogeneity was observed in all subgroups, and accuracy was reported to be highly operator dependent in most studies. An abbreviated protocol consisting of DWI and fast T2w imaging can potentially replace the full protocol MRE. Full protocol MRE will still have its role in identifying penetrating complications. MTI should be indicated in case of suspected fibrostenotic disease.

Impact of gadodiamide (Omniscan) on a beef liver catalase ex vivo model

Gadolinium is used in Magnetic Resonance Imaging scans to enhance image quality and allow doctors to more effectively diagnose patients. It is administered to patients through intravenous injection of gadolinium-based contrast agents (GBCAs). Although most of the injected gadolinium is excreted from the body soon after it is administered, studies have shown that some gadolinium remains in the body for extended periods of time. In patients with renal dysfunction, gadolinium retention has been associated with Nephrogenic Systemic Fibrosis, and even in patients with normal kidney function, long-term gadolinium deposits have been observed in the brain following exposure to GBCAs. The specific biochemical effects of gadolinium retention remain largely unknown, but it is possible that gadolinium may impact enzymatic activity. The present experiment investigated the effects of gadodiamide (brand name Omniscan), a common GBCA, on the function of catalase, a crucial biological enzyme that converts hydrogen peroxide into water and oxygen. We exposed beef liver to various concentrations of hydrogen peroxide both with and without gadodiamide, and we determined the Vmax and Km values of the catalase. We found that the presence of gadodiamide did not significantly inhibit catalase, which we hypothesize is due to the chelating agent present in gadodiamide. This work has important implications for understanding the biochemical effects of GBCAs and their potential impact on patient health.

Study of bone marrow microstructure in healthy young adults using intravoxel incoherent motion diffusion-weighted MRI.

Bone marrow is one of the most important organs in the human body. The evaluation of bone marrow microstructure and gender-related cellular and capillary networks in healthy young adults can help to better understand the process of bone metabolism. Intravoxel incoherent motion (IVIM) provides both diffusion and perfusion quantifications without requiring intravenous contrast agent injection. In this prospective study, 60 healthy young age-matched volunteers (30 men and 30 women) underwent MRI scans at 1.5 T using multi-b-value diffusion-weighted imaging on sagittal planes covering the lumbar bone marrow. The apparent diffusion coefficient (ADC), true ADC (D), pseudo-ADC (D*), and perfusion fraction (f) were calculated from the diffusion-weighted images using the mono- and bi-exponential models. Lumbar cancellous bone (L2-L4) was selected as the region of interest. An independent t-test was used to detect significant differences in ADC values and IVIM parameters between men and women. The differences in IVIM parameters among the L2, L3, and L4 groups were compared with analysis of variance. The D and f values in women were significantly higher than that in men (p = 0.001, 0.026). However, D* was significantly lower in women than that in men (p = 0.001). Furthermore, there was no significant gender difference for the conventional ADC value (p = 0.186). Moreover, there were no significant differences in the D, f, and D* values among the L2, L3, and L4 vertebras of women or men. IVIM parameters can show differences in bone marrow between young women and men. As a non-invasive method, it can assess bone marrow microstructure, such as cellularity and perfusion.

P.195 Quantitative skeletal muscle MRI of golden retriever muscular dystrophy dogs

Quantitative magnetic resonance imaging (MRI) is often proposed in clinical trials related to neuromuscular diseases. The intramuscular fat fraction (FF) is associated with functional decline while the quantification of water tissue relaxation times (T1 and T2) and the extracellular volume fraction (ECV) provides information about microstructural changes of the muscle tissue fraction that has not been replaced by fat. The Golden Retriever Muscular Dystrophy (GRMD) dog, an animal counterpart of Duchenne muscular dystrophy, represents an ideal model to evaluate the sensitivity to disease status and therapeutic response of these variables in a dystrophic context. MRI data from the pelvic limbs distal muscles of young and old GRMD (N = 14) and healthy dogs (N = 9) were acquired. A subgroup of the young GRMD dogs were under corticosteroids. The exam comprised water T2 mapping and T1 mapping before and after an intravenous injection of a gadolinium-based contrast agent from which ECV was calculated. In young dogs, we found that T1, T2 and ECV were significantly higher in all muscles of GRMD compared to healthy counterparts. Water T2 and ECV values were significantly lower in the corticosteroid compared to the naïve GRMD dogs. In old dogs, GRMD presented higher ECV values in all muscles. ECV classified dystrophic muscles with higher sensitivity and specificity than water T2 and native T1. Significant correlations were found between native T1 and water T2 in all the groups. Interestingly, ECV and water T2, as well as ECV and native T1 correlated significantly in all groups, except old GRMD dogs. In conclusion, native T1, water T2 and ECV measured by MRI are sensitive to the histological alterations encountered in dystrophic muscles. On a small cohort of GRMD dogs, the two latter variables were also sensitive to a corticosteroid treatment. By combining the different variables, we were able to distinguish different pathophysiological processes in young and old GRMD dogs.

COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF CONGENITAL HEART DISEASE

Aim of the study – Evaluate the value of multispiral computed tomography (MSCT) with intravenous contrast in the diagnosis of congenital heart disease (CHD) at the stage of preoperative preparation and choice of surgical tactics. Methods. Between January 2021 and June 2022, 30 CT cardiographies were performed in our center, of different age and mediastinal pathology. A 64-slice Somaton Siemens sensation 64 CT scanner complete with digital processing systems was used. The main vessels of the heart were examined with intravenous bolus injection of contrast agent. Image analysis included study of anatomy of the defect by three-plane tomograms and construction of multiplanar 3-D reconstructions. Results. Modern approaches to the imaging diagnosis of CHD in all age groups are presented. The role of CT-angiography with intravenous contrast in the diagnosis of congenital, acquired cardiovascular and thoracic pathology is shown. Qualitative assessment of CT-angiographic picture of CHD was performed. Conclusion. Our experience with CT cardiography in the examination of patients with CHD, in contrast to traditional ultrasound and invasive techniques, in most cases allows to obtain more valuable diagnostic information, especially extracardiac structures, which determines its significance in the examination of CHD. It details anatomy of malformations in reliable morphometric indices, diagnosis of aortic, pulmonary artery, right ventricular pathology, including pathology of its outflow tract, to assess ventricular-artery connections and atrialventricular connections.

P.62 Increased skeletal muscle extracellular volume fraction in patients with Becker muscular dystrophy assessed by quantitative magnetic resonance imaging

Quantitative magnetic resonance imaging (MRI) is increasingly proposed in clinical trials related to dystrophinopathies, including Becker muscular dystrophy (BMD). Extracellular volume fraction (ECV) is a candidate variable to characterize muscle tissues microstructure. Previous studies have demonstrated that the myocardium of BMD patients presented increased ECV. Given that cardiac muscle shares important structural features with skeletal muscles, we hypothesize that ECV could also be a sensitive biomarker to monitor pathological alterations of the skeletal muscle structure in BMD patients. We established the sensitivity of ECV quantification using magnetic resonance fingerprinting with water and fat separation (MRF T1-FF) as an imaging biomarker of skeletal muscle tissue alterations in BMD, by comparison with fat fraction (FF) and water relaxation time quantification. Data from the thighs of 28 BMD patients and 8 healthy volunteers were acquired. The MRI exam comprised FF mapping, water T2 mapping and water T1 mapping before and after an intravenous injection of a gadolinium-based contrast agent using MRF T1-FF from which ECV was calculated. Mann-Whitney tests, Kruskal-Wallis tests, ROC curves analysis and Spearman-rank correlation tests were performed. ECV was higher in dystrophic patients than in controls (0.20 [0.16 – 0.28] vs 0.07 [0.06 – 0.07], p<.001). In muscles of BMD patients with normal FF, ECV was also higher than in muscles of healthy controls (0.11 [0.10 – 0.13] vs 0.07 [0.06 – 0.09], p<.001). ECV classified dystrophic muscles with high sensitivity and specificity (AUC, 0.98; 95%CI: 0.96-0.99, p <.001), and correlated significantly with FF (ρ = .62, p < .001), water T2 (ρ = .56, p = .002), Walton score (ρ = .58, p = .001) and serum cardiac troponin-T level (ρ = .63, p < .001). In conclusion, muscle ECV measured with MRF represents a promising imaging biomarker for the early detection of skeletal muscle involvement in patients with Becker muscular dystrophy.

Should renal resistive index be considered as a routine predictor in newly diagnosed acute hydronephrosis in patients with unilateral renal colic?

Urinary tract stones are the most common causes of urinary tract obstruction, leading to patient hospitalization in the emergency room. This study is aimed to evaluate the use of the mean resistance index (mRI) to predict hydronephrosis in patients admitted for acute renal colic. This prospective study was performed on 100 patients who were admitted to the emergency department (ED) with unilateral renal colic (RC) problem. At the first visit, the following was done for all patients: 1. blood was taken from them for laboratory studies; 2. ECG and cardiological test; 3. plain film of the urinary tract; 4. аbdominal US; 5. bilateral color doppler ultrasound (CDUS) with renal RI measurement. Based on the information collected at different times during the experiment, patients were divided into two groups: the group that showed signs of dilatation (group A) and the group with hydronephrosis (group B). The obtained data were analyzed statistically by SPSS version 20. A mRI with a 0.68 cut off value was the most accurate (AUC:0.878), and Sensitive (90%) cut-off value for prediction of hydronephrosis development among patients presenting with RC and renal stone. This cut-off value also provided the highest positive (94%) and negative (76%) predictive values. CDUS with RI measurement is an easy and non-invasive method that provides useful information about urinary tract obstruction stones in patients with unilateral RC. In our study, this method was able to predict successfully the onset of acute renal dilatation. This was done with different levels of sensitivity, specificity, accuracy and diagnostic efficiency that were higher than ultrasound. Daily use of CDUS in ED can improve ultrasound, especially when other methods are contraindicated. For example, the methods by which the patient is exposed to radiation (pregnancy, allergies, renal failure, etc.) or intravenous injection of contrast agents (urography and CT).

Glymphatic MRI techniques in sleep and neurodegenerative diseases.

The purpose of this review article is to summarize the current in-vivo imaging techniques for the evaluation of the glymphatic function and discuss the factors influencing the glymphatic function and research directions in the future. The glymphatic system allows the clearance of metabolic waste from the central nervous system (CNS). The glymphatic pathway has been investigated using intrathecal or intravenous injection of a gadolinium-based contrast agent (GBCA) on MRI, so-called glymphatic MRI. The glymphatic MRI indirectly visualizes the dynamic CSF flow and evaluated the glymphatic function in the animal and human models. Several clinical and preclinical studies using glymphatic MRI have confirmed that the glymphatic function is impaired in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and idiopathic normal pressure hydrocephalus. Furthermore, physiologic process such as sleep facilitates the glymphatic clearance, thus clearing accumulation of protein deposition, such as amyloid or tau, potentially delaying the progression of neurodegenerative diseases. The glymphatic system plays a crucial role in clearing metabolic wastes in the brain. Glymphatic MR imaging using GBCA administration serves as a functional imaging tool to measure the glymphatic function and investigate various pathophysiologies of neurodegenerative diseases.

Development and Characteristics of Hearing Loss With the Progression of Endolymphatic Hydrops.

This study aims to explore how patients' hearing loss developed with the progression of endolymphatic hydrops and the characteristics of hearing loss at different stages. We collected 73 patients with definite or possible unilateral Meniere's disease or sudden hearing loss who underwent magnetic resonance imaging after intravenous contrast agent injection. There were 25 cases of isolated cochlear hydrops, 24 cases of isolated vestibular hydrops, and 24 cases of cochlear and vestibular hydrops. Primary outcome analyses included their evaluation of endolymphatic hydrops and hearing thresholds at low and high frequencies. The overall hearing threshold of patients with vestibular and cochlear hydrops was significantly higher than that of patients with isolated cochlear hydrops and patients with isolated vestibular hydrops. There was a significant correlation between low-frequency hearing loss and cochlear hydrops, and the low-frequency hearing threshold was proportional to the grade of cochlear hydrops. At low frequency, the hearing threshold of patients with isolated vestibular hydrops was lower than that of patients with isolated cochlear hydrops and patients with both cochlear and vestibular hydrops. The audiogram configurations of patients with isolated cochlear hydrops consist largely of flat type and up-sloping type. The audiogram configurations of patients with isolated vestibular hydrops and patients with both cochlear and vestibular hydrops are mainly flat type and down-sloping type. Patients present with low-frequency hearing loss in the early stage of endolymphatic hydrops. When the hydrops involves the whole cochlea and vestibule, the patients' hearing is impaired at both low and high frequencies.

PD07-08 FIBROBLAST ACTIVATION PROTEIN-SPECIFIC MRI PROVIDES IMPROVED TUMOUR MAPPING IN AN ORTHOTOPIC MODEL OF PROSTATE CANCER COMPARED TO PROSTATE SPECIFIC MEMBRANE ANTIGEN

You have accessJournal of UrologyCME1 May 2022PD07-08 FIBROBLAST ACTIVATION PROTEIN-SPECIFIC MRI PROVIDES IMPROVED TUMOUR MAPPING IN AN ORTHOTOPIC MODEL OF PROSTATE CANCER COMPARED TO PROSTATE SPECIFIC MEMBRANE ANTIGEN Nicole Dmochowska, Valentina Milanova, Anil Shetty, Ramesh Mukkamala, Madduri Srinivasarao, Eric Walser, Phil Low, and Benjamin Thierry Nicole DmochowskaNicole Dmochowska More articles by this author , Valentina MilanovaValentina Milanova More articles by this author , Anil ShettyAnil Shetty More articles by this author , Ramesh MukkamalaRamesh Mukkamala More articles by this author , Madduri SrinivasaraoMadduri Srinivasarao More articles by this author , Eric WalserEric Walser More articles by this author , Phil LowPhil Low More articles by this author , and Benjamin ThierryBenjamin Thierry More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002526.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: MRI guided focal therapies of prostate cancer have the potential to reduce treatment related side effects without sacrificing oncological outcomes. Molecular MRI with agents targeted to tumour tissues enhances tumour margin detection and consequently treatment guidance/planning. Prostate specific membrane antigen (PSMA) expression is currently the gold standard for molecular imaging of prostate cancer. Fibroblast activation protein (FAP) is an extracellular transmembrane protein expressed on cells of the tumour microenvironment, particularly in stromal and vascular components. FAP has been gaining momentum as a pan-cancer marker(DOI: 10.2967/jnumed.119.227967) as its overexpression often correlates with cancer severity, including in prostate cancer (DOI: 10.1371/journal.pone.0116683) and has been found to be negligibly expressed in healthy tissue. Our objective was to compare MRI contrast of PSMA-targeting and FAP-targeting magnetic nanoparticles (MNPs) in an orthotopic murine model of prostate cancer. METHODS: Control (no ligand), FAP and PSMA-targeted MNPs were prepared with modification of an MRI agent (FerroTrace, Ferronova) currently undergoing a phase 1 clinical trial. In vitro binding was evaluated in PSMA and FAP positive cell lines. To form orthotopic tumours, LNCaP cells (PSMA+ human prostate cancer) were injected into the prostate. After 4-6 weeks of tumour growth, mice underwent 16.4T T2-weighted 3D MRI 24 hours after intravenous injection of contrast agents. Enhancement of MRI contrast in tumours was quantified by determining the proportion of pixels with low signal intensity throughout regions of interest. Accumulation of MNPs in prostate tumours at 24 hours post injection was confirmed ex vivo by Prussian blue staining. RESULTS: PSMA and FAP-MNPs demonstrated specific binding in vitro. MRI contrast of tumours was increased in FAP (p<0.001) and PSMA-MNPs (p<0.05) but not control MNPs (p>0.05), relative to orthotopic tumours with no injected MNPs. FAP-MNPs provided increased contrast relative to PSMA-MNPs (∼10% enhancement, p<0.05). Increased accumulation of FAP-MNPs in prostate tumours was observed on tissue sections compared to PSMA-MNPs. Control-MNPs showed minimal tumour accumulation. CONCLUSIONS: These results suggest that FAP-targeting MNPs could enhance the MRI of prostate tumours and assist in the delivery of precise focal treatment. Source of Funding: NHMRC Development Grant 1158755 © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e101 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nicole Dmochowska More articles by this author Valentina Milanova More articles by this author Anil Shetty More articles by this author Ramesh Mukkamala More articles by this author Madduri Srinivasarao More articles by this author Eric Walser More articles by this author Phil Low More articles by this author Benjamin Thierry More articles by this author Expand All Advertisement PDF DownloadLoading ...

Short-Term Efficacy of Transcranial Focused Ultrasound to the Hippocampus in Alzheimer's Disease: A Preliminary Study.

Preclinical studies have suggested that low-intensity transcranial focused ultrasound (tFUS) may have therapeutic potential for Alzheimer’s disease (AD) by opening the blood–brain barrier (BBB), reducing amyloid pathology, and improving cognition. This study investigated the effects of tFUS on BBB opening, regional cerebral metabolic rate of glucose (rCMRglu), and cognitive function in AD patients. Eight patients with AD received image-guided tFUS to the right hippocampus immediately after intravenous injection of microbubble ultrasound contrast agents. Patients completed magnetic resonance imaging (MRI), 18F-fluoro-2-deoxyglucose positron emission tomography (PET), and cognitive assessments before and after the sonication. No evidence of transient BBB opening was found on T1 dynamic contrast-enhanced MRI. However, immediate recall (p = 0.03) and recognition memory (p = 0.02) were significantly improved on the verbal learning test. PET image analysis demonstrated increased rCMRglu in the right hippocampus (p = 0.001). In addition, increases of hippocampal rCMRglu were correlated with improvement in recognition memory (Spearman’s ρ = 0.77, p = 0.02). No adverse event was observed. Our results suggest that tFUS to the hippocampus of AD patients may improve rCMRglu of the target area and memory in the short term, even without BBB opening. Further larger sham-controlled trials with loger follow-up are warranted to evaluate the efficacy and safety of tFUS in patients with AD.

Utility of dual-energy contrast-enhanced spectral mammography for the diagnosis of multicentric breast cancer

Background. Breast cancer (BC) can be unifocal, multifocal, multicentric (MCBC) and bilateral according to number and localization of tumors. MCBC has different clinical and biological characteristics compared to unifocal BC, for example, a higher risk of lymph node involvement, a more aggressive natural history and a worse prognosis. Therefore, accurate diagnosis and detection of MCBC is one of the main tasks of imaging.Objective: to compare diagnostic accuracy of contrast enhanced spectral mammography (CESM) and digital mammography (DM) in the diagnosis of MCBC.Materials and methods. The study included 438 women with suspected BC. The results of DM and CESM were compared with the results of a pathomorphological study performed after surgery or biopsy to assess the effectiveness of imaging modalities. DM was performed for all women using a Senographe DS (GE, USA) unit. CESM was performed after intravenous injection of non-ionic contrast agents using injector with breast compression in the craniocaudal and mediolateral projections. The study was performed for both glands regardless of the location of the suspicious lesion in order to timely diagnose clinically asymptomatic bilateral cancer. The final diagnosis was made based on the results of the pathomorphological examination. MCBC was diagnosed when two or more tumors at a distance of 3 cm or more from each other were detected. Visualization of additional grouped calcifications of malignant type occupying a small portion of breast tissue (more than 15 pieces per 1 sq. cm) was considered as another mammographic sign of MCBC.Results. According to the pathomorphological examination BC was diagnosed in 154 (35 %) women out of 438 examined patients. MCBC was identified in 25 (16 %) of 154 patients. CESM was more effective than DM in detecting MCBC with sensitivity of 88.0 % vs 48.0 % (p = 0.002), accuracy of 92.2 % vs 90.9 %, negative predictive value of 97.6 % vs 90.8 % (p = 0.02), respectively. But the specificity was significantly higher in DM than in CESM – 99.2 % vs 93.0 % (p = 0.009), respectively, and the positive predictive value did not differ significantly (p = 0.12).Conclusion. CESM is a more sensitive method for diagnosing MCBC compared to DM with sensitivity of 88.0 % vs 48.0 %. The high negative predictive value of CESM (97.6 %) confirms the fact that this modality is an effective method for planning surgery and radiation therapy.

Computer tomography in diagnostics and treatment of inflammatory complications of diverticular disease of the colon

AIM: to evaluate the role of computed tomography (CT) in the treatment and diagnostic algorithm in patients with complicated diverticular disease (CDD).PATIENTS AND METHODS: during the period from 2014 to 2020, 165 hospitalized patients with complications of CDD included in the study. Fifteen (9.1%) patients were hospitalized for elective indications and 150 (90.9%) as emergencies. The indications for hospitalization were inflammatory complications of CDD. Computed tomography with intravenous contrast was performed in 89 (53.9%) patients. The study was performed on a 64-slice CT “Philips Brilliance 64” with intravenous bolus injection of a low-osmolar iodine-containing contrast agent. The absence of the CT in the remaining patients is due to the presence of classical symptoms of acute diverticulitis with a previously verified diagnosis of CDD, the presence of an informative transabdominal ultrasound, as well as the refusal of patients from CT.RESULTS: the CT allowed to verify the presence of diverticula in the patients, to reveal the distinctive CT signs and pathognomonic symptoms of inflammatory complications of CDD, as well as to establish the severity of the complications that occurred. The specific signs of the destruction of the diverticulum and the complications developed were abdominal mass, abscess, peritonitis, and fistula. Besides the diagnostic value, CT scan permitted to choose the treatment approach and to clarify indications for surgery. Besides that, some CDD complications revealed by CT were considered as a predictor of ineffectiveness of conservative treatment, which requires surgery.CONCLUSION: CT is a valuable diagnostic method for CDD which allows to determine timely the clinical form of inflammatory complication, to find out indications for surgery and to predict high risk of recurrence.

Comparability of coronary risk assessment methods with chest ultra-LDCT and CT coronography with ECG synchronization

Purpose. To assess the comparability of coronary calcium values measured on ultralow-dose computed tomography studies without ECG-synchronization versus a) non-contrast computed tomography with ECG synchronization, b) CT coronography with ECG synchronization.Materials and methods. The study comprised 283 studies: 68 patients who underwent contrast-free ultra-LDCT without ECG synchronization and contrast-free CT with ECG synchronization performed in a single visit, and 49 patients with contrast-free ultra-LDCT without ECG synchronization, non-contrast CT with ECG synchronization, and CT coronography with ECG synchronization and intravenous injection of contrast agent, also carried out in one visit, meeting all inclusion and exclusion criteria of the study.Quantitative coronary calcium values were calculated with the Agatston score and the CAC-DRS scale (score of calcification degree from 0 to 3 and the number of affected arteries from 0 to 4 points). The degree of coronary artery stenosis was analyzed with CAD-RADS scale (0-5).The above parameters were compared using visual/quantitative assessment of coronary calcium on ultra-LDCT without ECG synchronization and visual/quantitative assessment for CT with ECG synchronization, as well as the degree of stenosis on CT coronography in the same patients.Results. Based on the results of accuracy indices comparison, the possibility to use quantitative scale (Agatston score, CAC-DRS quantitative scale) to assess coronary calcification in the lung cancer screening in comparison with ECG-synchronized CT was determined during interpretation of ultra-LDCT without ECG synchronization. The correlation matrix to assess correlation between visual, quantitative scales of coronary artery changes and calcification at ultra-LDCT without ECG synchronization and quantitative scale at CT with ECG synchronization vs. CT coronography identifies very strong positive statistically significant correlations.Conclusion. Methods of coronary calcinosis assessment with chest ultra-LDCT and CT with ECG synchronization are comparable, therefore it is possible to assess coronary calcium in lung cancer screening by ultra-LDCT data at a reliable-high level using both quantitative and visual CAC-DRS scales.

Seeing more with less: virtual gadolinium-enhanced glioma imaging

MRI is the main modality to diagnose and monitor the evolution and treatment of brain tumours. Radiological tumour grading relies on evidence of abnormal blood–brain barrier permeability, achieved by intravenous injection of gadolinium-based contrast agents (GBCA), leading to enhanced signal intensity on T1-weighted images. The current goal in glioma surgery is resection of the enhancing tumour parts and the response assessment in neuro-oncology (RANO) criteria for monitoring glioma treatment response heavily rely on the demonstration of recurring or enlarging enhancing tumour.