Contrast Injection Research Articles

An Accelerated Spectroscopic MRI Metabolite Quantification Based on a Deep Learning Method for Radiation Therapy Planning in Brain Tumor Patients

Background: Spectroscopic MRI (sMRI) is a quantitative imaging technique that maps infiltrated tumors in the brain without contrast injections. In a previous study (NCT03137888), sMRI-guided radiation treatment extended patient survival, showing promise for clinical translation. The spectral fitting of individual voxels in an sMRI dataset generate metabolite concentration maps that guide treatment. The established spectral analysis methods use iterative least-squares fitting (FITT) that are computationally demanding. This study compares the performance of NNFit, a neural network-based, accelerated spectral fitting model, to the established FITT for metabolite quantification and radiation treatment planning. Methods: NNFit is a self-supervised deep learning model trained on 50 ms echo-time (TE) sMRI data to estimate metabolite levels of choline (Cho), creatine (Cr), and NAA. We trained the model on 30 GBM patients (56 scans) and tested it on 17 GBM patients (29 scans). NNFit’s performance was compared to the FITT using structural similarity indices (SSIM) and the Dice coefficient. Results: NNFit significantly improved processing speed while maintaining strong agreement with FITT. The radiation target volumes defined by Cho/NAA ≥ 2x were visually comparable, with fewer artifacts in NNFit. Structural similarity indices (SSIM) indicated minimal bias and high consistency across methods. Conclusions: This study highlights NNFit’s potential for rapid, accurate, and artifact-reduced metabolic imaging, enabling faster radiotherapy planning.

"Synthetic" DSC Perfusion MRI with Adjustable Acquisition Parameters in Brain Tumors Using Dynamic Spin-and-Gradient-Echo Echoplanar Imaging.

Normalized relative cerebral blood volume (nrCBV) and percentage of signal recovery (PSR) computed from dynamic susceptibility contrast (DSC) perfusion imaging are useful biomarkers for differential diagnosis and treatment response assessment in brain tumors. However, their measurements are dependent on DSC acquisition factors, and CBV-optimized protocols technically differ from PSR-optimized protocols. This study aimed to generate "synthetic" DSC data with adjustable synthetic acquisition parameters using dual-echo gradient-echo (GE) DSC datasets extracted from dynamic spin-and-gradient-echo echoplanar imaging (dynamic SAGE-EPI). Synthetic DSC was aimed at: 1) simultaneously create nrCBV and PSR maps using optimal sequence parameters, 2) compare DSC datasets with heterogeneous external cohorts, and 3) assess the impact of acquisition factors on DSC metrics. Thirty-eight patients with contrast-enhancing brain tumors were prospectively imaged with dynamic SAGE-EPI during a non-preloaded single-dose contrast injection and included in this cross-sectional study. Multiple synthetic DSC curves with desired pulse sequence parameters were generated using the Bloch equations applied to the dual-echo GE data extracted from dynamic SAGE-EPI datasets, with or without optional preload simulation. Dynamic SAGE-EPI allowed for simultaneous generation of CBV-optimized and PSR-optimized DSC datasets with a single contrast injection, while PSR computation from guideline-compliant CBV-optimized protocols resulted in rank variations within the cohort (Spearman's ρ = 0.83-0.89, i.e. 31%-21% rank variation). Treatment-naïve glioblastoma exhibited lower parameter-matched PSR compared to the external cohorts of treatment-naïve primary CNS lymphomas (PCNSL) (p<0.0001), supporting a role of synthetic DSC for multicenter comparisons. Acquisition factors highly impacted PSR, and nrCBV without leakage correction also showed parameter-dependence, although less pronounced. However, this dependence was remarkably mitigated by post-hoc leakage correction. Dynamic SAGE-EPI allows for simultaneous generation of CBV-optimized and PSR-optimized DSC data with one acquisition and a single contrast injection, facilitating the use of a single perfusion protocol for all DSC applications. This approach may also be useful for comparisons of perfusion metrics across heterogeneous multicenter datasets, as it facilitates post-hoc harmonization.

A Systematic Review of Indocyanine Green Lymphography (ICGL) Imaging for the Diagnosis of Primary Lymphoedema.

This systematic review aims to evaluate the use of Indocyanine Green Lymphography (ICGL) for the investigation of the lymphatics in the lower limbs of primary lymphoedema patients. MEDLINE and EMBASE articles from 01/01/2000 to 01/09/2023 were searched for. A total of 11 studies were included in the review after a two-stage screening process. Data on patient demographics, ICG contrast injection technique, imaging protocols and imaging outcomes were summarised and reviewed in detail. The review highlights the lack of commonality in protocols used. Factors important for good imaging are highly variable, particularly the number of injections, their location and whether they are delivered intradermally or subcutaneously. ICGL has strong potential to become a diagnostic tool to diagnose lymphoedema, due to its non-ionising nature and cost-effectiveness. However due to the lack of thorough phenotyping and genotyping of patients included in the studies, uncertainty still exists as to the value of the described imaging features such as splash, starburst and diffuse dermal rerouting patterns. Future studies, therefore, should aim to explore the diagnostic utility of ICGL for lymphoedema further through the imaging of primary lymphoedema patients with a confirmed genetic diagnosis and using standardised imaging protocols. ICGL is a strong candidate for advancing the diagnosis and understanding of primary lymphoedema, and monitoring response to treatment, but protocol heterogeneity and a lack of consistency in reporting imaging details and patient phenotyping currently hold it back.

PEGylated Ultrasmall Iron Oxide Nanoparticles as MRI Contrast Agents for Vascular Imaging and Real-Time Monitoring.

Accurate imaging evaluations of pre- and post-treatment of cardiovascular diseases are pivotal for effective clinical interventions and improved patient outcomes. However, current imaging methods lack real-time monitoring capabilities with a high contrast and resolution during treatments. This study introduces PEGylated ultrasmall iron oxide nanoparticles (PUSIONPs), which have undergone comprehensive safety evaluations, boasting an r1 value of 6.31 mM-1 s-1, for contrast-enhanced magnetic resonance angiography (MRA). Systematic comparisons against common clinical methods in rabbits reveal that PUSIONPs-enhanced MRA exhibited improved vascular contrast, clearer vascular boundaries, and superior vessel resolution. Moreover, owing to their nanosize, PUSIONPs demonstrate significantly prolonged blood circulation compared to small molecular contrast agents such as Magnevist and Ultravist. This extended circulation enables captivating real-time monitoring of thrombolysis treatment for up to 4 h in rabbit models postsingle contrast agent injection. Additionally, in larger animal models such as beagles and Bama minipigs, PUSIONPs-enhanced MRA also showcases superior contrast effects, boundary delineation, and microvessel visualization, underscoring their potential to transform cardiovascular imaging, particularly in real-time monitoring and high-resolution visualization during treatment processes.

Ultrasound-guided needle positioning confirmation with injection of saline solution for nodal dynamic contrast-enhanced MR-lymphangiography in pediatric patients.

To assess the success rate of confirmation of ultrasound-guided intranodal needle positioning by saline injection for dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) in pediatric patients. Data from children undergoing nodal DCMRL after ultrasound-guided needle positioning into inguinal lymph nodes and validation of the needle position by injection of plain saline solution between 05/2020 and 12/2022 were reviewed. On injection of saline solution, adequate needle position was confirmed by lymph node distension without leakage. Detection rates and lymph node diameters were recorded. Technical success of needle placement was defined as enhancement of ipsilateral iliac draining lymph vessels on DCMRL, while clinical success was based on enhancement of central lymphatics and/or lymphatic pathologies being observed. One hundred sixteen DCMRLwere performed in 90 children (58 male, mean age 6.1 years, range 3 weeks-18 years). In 232/232 groins lymph nodes were identified on ultrasound with a mean diameter of 2.5 mm (smallest diameter 1 mm in n = 24 patients). Due to skin inflammation, no puncture was performed in 2/232 groins. Saline injection showed lymph node distension in 230/230 punctured nodes. On MR contrast injection enhancement of draining lymph vessels was seen in 228/230 nodes. In 1/230 nodes, in-bore needle retraction led to lymphatic enhancement, so a total of 229/230 needle placements were technically successful. One of the 230 DCMRLs was successful with only a unilateral contrast application. Overall, 116/116 DCMRLs were clinically successful. Confirmation of ultrasound-guided needle positioning for nodal DCMRL using saline injection is a reliable technique with a very high success rate in pediatric patients with small lymph nodes. Question Evaluation of ultrasound-guided injection needle positioning for dynamic contrast-enhanced MR-lymphangiography in children requires validation. Findings Confirmation of needle positioning by ultrasound-guided saline injection is a reliable technique with a very high success rate for MR-lymphangiography in pediatric patients. Clinical relevance Intranodal needle position for dynamic contrast-enhanced lymphangiography can be confirmed with a very high success rate using saline injection alone in a pediatric cohort.

Iatrogenic aorto-coronary dissection triggered by contrast injection during coronary evaluation with optical frequency domain imaging.

Iatrogenic aorto-coronary dissection triggered by contrast injection during coronary evaluation with optical frequency domain imaging.

Long-term effects of linear versus macrocyclic GBCAs on gene expression in the central nervous system of mice

BackgroundWe examined chronic gadolinium retention impact on gene expression in the mouse central nervous system (CNS) after injection of linear or macrocyclic gadolinium-based contrast agents (GBCAs).MethodsFrom 05/2022 to 07/2023, 36 female mice underwent weekly intraperitoneal injections of gadodiamide (2.5 mmol/kg, linear), gadobutrol (2.5 mmol/kg, macrocyclic), or saline. Mice were sacrificed on day 29 or 391 after a 1-year washout. Assessments included magnetic resonance imaging (MRI), mechanical hyperalgesia tests, and inductively coupled plasma mass spectrometry to measure gadolinium levels. Ribonucleic acid (RNA) sequencing and bioinformatic analyses identified differentially expressed genes (DEGs), with validation by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB).ResultsPost-gadodiamide, MRI showed increased signal intensity in the deep cerebellar nuclei (pre, 0.997 ± 0.006 versus post, 1.086 ± 0.013, p < 0.001). Mechanical hyperalgesia tests indicated transient sensory changes. After 1-year, gadolinium retention was noted in the brain (5.92 ± 0.32 nmol/kg) and spinal cord (1.23 ± 0.66 nmol/kg) with gadodiamide, compared to saline controls (0.06 ± 0.02 nmol/kg in brains and 0.28 ± 0.06 nmol/kg in spinal cords). RNA sequencing identified 17 shared DEGs between brain and spinal cord in the gadodiamide group on day 391, with altered Hmgb2 and Sgk1 expression confirmed by qRT-PCR and WB. Reactome pathway analysis showed enrichment in neuroinflammation pathways. No DEGs were detected in brains on day 29.ConclusionChronic gadolinium deposition from repeated linear GBCA but not macrocyclic administration causes significant gene expression alterations in the mouse CNS, particularly affecting neuroinflammation pathways.Relevance statementThis study examined the long-term impact of chronic gadolinium retention on gene expression in the mouse CNS, uncovering significant changes associated with neuroinflammation pathways after repeated administration of linear GBCA, but not with macrocyclic GBCA. These findings highlight the importance of further research on the long-term safety of linear GBCA in medical imaging.Key PointsChronic gadolinium retention alters gene expression in the mouse central nervous system.Significant neuroinflammatory pathway changes were observed after linear gadodiamide exposure.MRI showed increased signal intensity in deep cerebellar nuclei after gadodiamide injection.Graphical

Comparison of 3D BFFE and 3D TRANCE on pulmonary artery imaging with two T-SLIP placement strategies.

3D BFFE and TRANCE can provide a visualization of pulmonary vessels without injection of contrast agent. T-SLIP can observe a large area of vessels using an arterial spin labeling technique. 3D BFFE and TRANCE with two T-SLIP placement strategies were compared on pulmonary artery imaging. Ten male and thirteen female healthy volunteers were recruited in the present study. Each subject underwent non-contrast-enhanced pulmonary MRA. Four protocols were involved in the present study as follows: 3D BFFE with T-SLIP covering vena cava (VC) and right atrium and ventricle (RV), respectively; 3D TRANCE with T-SLIP covering VC and RV, respectively. The SNR were measured at eight ROIs, while CNR were measured at five ROIs. The number of visualized branch and image quality were analyzed by two radiologists. The differences of metrics among different imaging strategies were compared. SNR and CNR were compared between two T-SLIP placement strategies using a paired t-test. The branches number and image quality were compared between two T-SLIP placement strategies using a rank-sum test. The agreement of subjective assessment was conducted using a Kappa test. There were significant differences at all ROIs between TRANCE and BFEE with T-SLIP on RV (all P values <0.01). TRANCE with T-SLIP on RV exhibited a higher CNR at all five ROIs compared with BFFE with T-SLIP on RV. TRANCE with T-SLIP on RV performed better on the number of observed branches and image quality compared with BFFE with T-SLIP on RV. 3D TRANCE with T-SLIP on RV can provide a higher SNR and image quality among four MR protocols, and thus may be a potential non-contrast enhanced technique in the visualization of pulmonary artery.

Pancreatic tuberculosis revealed by a mass with neoplastic appearance: a case report

Introduction. Pancreatic tuberculosis is an extremely rare form of extrapulmonary tuberculosis. This condition can be challenging to diagnose due to its rarity, nonspecific symptoms and radiological features that may mimic a neoplastic origin. Case report. A 46-year-old immunocompetent patient with no past history of tuberculosis exposure presented with spontaneously resolving jaundice over the past month, accompanied by nonspecific fever episodes and general fatigue with no other associated digestive symptoms. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) scans revealed a poorly defined, partially necrotic mass in the pancreatic head with heterogeneous hypodensity and enhancement after contrast injection. Additionally, there were nodal and hilar macro-nodal lesions with necrotic appearances, as well as peripancreatic lymphadenopathy. The patient was scheduled for an endoscopic ultrasound (EUS) examination, which revealed the presence of a heterogeneous lesion with areas of necrosis in the posterosuperior aspect of the head and isthmus of the pancreas, accompanied by perilesional and coeliac lymphadenopathies with necrotic centres. EUS-guided tissue sampling allowed the diagnosis of pancreatic tuberculosis, with both histological examination and GeneXpert MTB/RIF testing rapidly positive for Mycobacterium tuberculosis, followed by culture on solid Loewenstein–Jensen medium. The patient responded well to antitubercular chemotherapy. Conclusion. Pancreatic tuberculosis, though rare, should be considered in cases of pancreatic masses, especially in endemic regions. Tissue samples with necrosis should be tested for M. tuberculosis using GeneXpert and Loewenstein–Jensen culture. This work highlights the GeneXpert MTB/RIF test as highly sensitive, specific and fast, making it ideal for diagnosing extrapulmonary tuberculosis, particularly when smear results are negative.

Application value of split-bolus contrast injection combined with dual-energy CT scanning technology in pediatric CTU imaging.

To explore the clinical value of combining split-bolus contrast injection with dual-energy CT(DECT) scanning technology in pediatric computed tomography urography (CTU) imaging. A total of 128 children aged 0-17years were prospectively selected and randomly assigned to three groups: A, B, and C. For Group A, a high-pitch flash mode was employed, where a single bolus of contrast agent was followed by four-phase scanning (noncontrast, cortex, medulla, and excretory phases). In Group B, a dual-energy scanning mode was used with a split-bolus injection technique (50% of the contrast agent was administered initially, followed by the remaining 50% after 37-43s), and the children underwent two-phase scanning (corticomedullary and excretory phases). In Group C, dual-energy scanning was similarly used with a split-bolus injection technique (65% contrast agent was administered initially, followed by the remaining 35% after 37-43s), along with two-phase scanning (corticomedullary and excretory phases). Virtual noncontrast (VNC) images were obtained from the corticomedullary phase images using iodine subtraction techniques for Groups B and C. The image quality and radiation dose across the groups were compared and analysed. When the CT values of the renal cortex, erector spinae muscles, and standard deviation (SD) values were compared between Group A's cortical phase and Groups B and C's corticomedullary phases, the order was Group B > Group C > Group A (P < 0.05). The comparison of the cortical CNR and SNR between Group A's cortical phase and Groups B's and C's corticomedullary phases (cortices) revealed that Group C > Group B > Group A (P < 0.05). The comparison of the medullary CNR and SNR between Group A's medullary phase and Groups B and C's corticomedullary phases (medulla) showed that Group A > Group C > Group B (P < 0.05). The scores for the VNC images in Groups B and C were lower than those for the true noncontrast (TNC) images in Group A (P > 0.05). In the subjective evaluations of the corticomedullary and excretory phase images, Group B > Group C > Group A (P < 0.05). The comparison of radiation doses revealed that Group B < Group C<Group A (P < 0.05). A significant correlation was found between BMI and the effective radiation dose (P < 0.01), with a correlation coefficient of 0.62. The combination of split-bolus contrast injection and DECT enhances image quality in pediatric CTU while reducing radiation dosage.

Triphasic Computed Tomography for Characterization of Liver Lesions Identified on Ultrasonography

Background: Liver disease is the leading cause of death in Pakistan and Asia. Liver carcinoma is the most prevalent cancer in the world. Identification of cancer at an early stage can help in better management of the disease and improved prognosis. Computed tomography can perform scans at different phases after contrast is administered. It is the most effective tool for the diagnosis of tumors and different types of lesions. Our objective of the study was to characterize the liver lesions identified on ultrasonography and differentiate between benign and malignant lesions at Bilal Hospital Rawalpindi. Methods: This cross-sectional quantitative study was conducted at Bilal Hospital, Rawalpindi, Pakistan, to evaluate liver lesions using triphasic CT. Data from 50 reports were analyzed, focusing on hepatic lesions, hepatomegaly, cirrhosis, and portal hypertension identified through ultrasonography. Patients over 30 were included, while those under 30, pregnant, contrast-allergic, or with abnormal renal function tests were excluded. Triphasic CT scans were performed with a 64-slice scanner, capturing arterial, portal venous, and delayed phases after contrast injection. Radiologists reported the scans, and data were analyzed using SPSS-25, ensuring patient consent, confidentiality, and privacy. Results: In this study, 28% of patients had benign liver lesions, with focal nodular hyperplasia (14%) being the most common, followed by hepatic cysts (4%) and hemangiomas (10%). Malignant lesions were observed in 62% of patients, with hepatocellular carcinoma (36%) being the most prevalent, followed by secondary metastases (10%), cholangiocarcinoma (8%), and focal hepatic lesions (8%). The most frequently observed condition was hepatocellular carcinoma. Conclusions: The study concludes that there is a significant prevalence of both benign and malignant liver lesions in patients over 30 years, with hepatocellular carcinoma being the most common malignancy and focal nodular hyperplasia, the most frequent benign lesion. The findings emphasize the crucial role of triphasic CT in accurately diagnosing and differentiating liver lesions, aiding in effective treatment planning.

Reliability of post-contrast deep learning-based highly accelerated cardiac cine MRI for the assessment of ventricular function.

The total examination time can be reduced if high-quality two-dimensional (2D) cine images can be collected post-contrast to minimize non-scanning time prior to late gadolinium-enhanced imaging. This study aimed to assess the equivalency of the pre-and post-contrast performance of 2D deep learning-based highly accelerated cardiac cine (DL cine) imaging by evaluating the image quality and the quantification of biventricular volumes and function in the clinical setting. Thirty patients (20 men, mean age 53.7 ± 17.8 years) underwent cardiac magnetic resonance on a 1.5 T scanner for clinical indications, and pre- and post-contrast DL cine images were acquired with a short-axis view. Image-quality was scored according to three main criteria: the blood-to-myocardial contrast, endocardial edge delineation, and presence of motion artifacts throughout the cardiac cycle. Biventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and left ventricular mass (LVM) were analyzed and compared between the pre- and post-contrast DL cine images. The actual median time of 2D DL cine acquisition was 38.4 ± 9.1 s. There were no significant differences in the image quality scores between pre- and post-contrast DL cine images (p > 0.05). In the volume and functional analysis, there was no significant difference in terms of biventricular EDV, ESV, SV, EF, and LVM (p > 0.05). The performance of 2D DL cine is equivalent before and after contrast injection for the assessment of image quality and ventricular function in the clinical setting.

Diagnostic capabilities of cardiac computed tomography in the preoperative diagnosis of hypertrophic cardiomyopathy

BACKGROUND: A comprehensive approach to studying hypertrophic cardiomyopathy with diagnostic equipment and the latest scanning methods will ensure quality control and effective treatment of patients with this condition. The implementation of innovative technologies and computer calculation using next-generation scanners may become relevant and promising in studying various phenotypes of left ventricular remodeling in combination with abnormalities of the chordopapillary apparatus of the mitral valve and myocardial structure. AIM: To examine the diagnostic capabilities of computed tomography in the preoperative examination of various hypertrophic cardiomyopathy phenotypes. MATERIALS AND METHODS: The retrospective data analysis included 47 patients with hypertrophic cardiomyopathy (mean age, 52±7 full years) before surgical correction. computed tomography was performed using our protocol with automatic bolus tracking in the left atrium with a 90 HU threshold and biphasic contrast injection to assess the heart chambers and coronary arteries anatomy and mitral valve morphology. Moreover, to assess myocardial structure remodeling, iodine dual-energy computed tomography maps obtained with delayed contrast enhancement were analyzed. All patients with hypertrophic cardiomyopathy were classified by morphological types. The anatomy of chordopapillary apparatus was evaluated in each case. RESULTS: This study demonstrated variability in hypertrophic cardiomyopathy phenotypes, which were conventionally divided into five morphological categories, but not restricted by them. Among the patients, 26 (55%) had diffuse septum hypertrophic cardiomyopathy, 5 (11%) had midventricular hypertrophic cardiomyopathy, 2 (4%) had midventricular obstruction and apical aneurysm, 8 (18%) had focal basal septum hypertrophic cardiomyopathy, 4 (8%) had concentric hypertrophic cardiomyopathy, and the remaining 4 (8%) had apical hypertrophic cardiomyopathy. Most patients were diagnosed with chordopapillary abnormalities of the mitral valve, categorized by papillary muscle number and position, and the ratio of chords to muscles. In 10 (21%) patients, data on the myocardial bridge of a coronary artery were obtained, whereas 3 (14%) of them had dynamic stenosis. All patients had focal iodine uptake on dual-energy computed tomography maps. An extracellular volume increase was observed in 10 out of 13 (76%) patients. As shown by dual-energy computed tomography, the mean extracellular volume of the left ventricular myocardium was 30.58% (95% confidence interval, 27–34%). CONCLUSION: Our scanning protocols developed with computed tomography scanners of various generations enable to evaluate the specific morphological patterns of hypertrophic cardiomyopathy in a single study and provide a detailed interpretation of the geometry of cardiac valves and chambers, left ventricular function, state of the coronary bed, and structural changes of the left ventricular myocardium.

A feasibility study of using virtual noncontrast images synthesized from dual-energy computed tomography for radiotherapy treatment planning.

In the traditional computed tomography (CT) simulation process, patients need to undergo CT scans before and after injection of iodine-based contrast agent, resulting in a cumbersome workflow and additional imaging dose. Contrast-enhanced spectral CT can synthesize true contrast-enhanced (TCE) images and virtual noncontrast (VNC) images in a single scan without geometric misalignment. To improve work efficiency and reduce patients' imaging dose, we studied the feasibility of using VNC images for radiotherapy treatment planning, with true noncontrast (TNC) images as references and explored its dosimetric advantages compared to using TCE images. Specifically, this study examined tumors near bones, including cases of bone metastasis and myeloma. A total of 54 patients (20 patients with cervical cancer, 15 patients with esophageal cancer, and 15 patients with laryngeal cancer, and 4 patients with bone metastasis or hip replacement) who underwent non-contrast-enhanced and contrast-enhanced spectral CT simulation were retrospectively enrolled between July 2023 and March 2024. The study was approved by the institutional review board. The CT images were acquired using a second-generation fast kilovoltage peak-switching CT. Treatment plans for photon radiotherapy were optimized and calculated using TNC images and recalculated based on TCE and VNC images. To evaluate image and dosimetric equivalent, several metrics, including Hounsfield unit (HU) value differences, gamma pass rates and dose-volume histogram (DVH) parameters of planning target volume (PTV), and organs at risk (OARs), were compared. In terms of HU value difference, for the majority of patients, the HU value differences of the PTV between TCE and TNC images (36.7±23.9 and 27.8±2.1 in esophageal and laryngeal cancer, respectively) were greater than those between VNC and TNC images (10.59±25.8 and 3.55±1.9 in esophageal and laryngeal cancer, respectively). Regarding dosimetry, the gamma pass rates between VNC and TNC were 1 in 2%/2 mm and 3%/3 mm. Most DVH parameter differences were less than 1% between the VNC and TNC plans and between TCE and TNC plans. Meanwhile, in some blood-rich OARs such as heart and small intestine, VNC shows dosimetric potential compared to TCE based on the statistically significant DVH parameters differences. By analyzing radiotherapy treatment plans with target areas located in different locations, including tumors near bones such as bone metastasis, we preliminarily verified the feasibility of using VNC images for photon dose calculation. This approach can effectively improve clinical workflow and reduce the image dose to patients.

Can preoperative percutaneous injection of ultrasound contrast agent locate sentinel lymph nodes of breast cancer?

We evaluated the ability and accuracy of preoperative identification and localization of sentinel lymph nodes (SLNs) using intradermal injection of ultrasound contrast agent. Prospectively recruited 191 early breast cancer patients with clinically negative axillary lymph nodes (ALNs). All participants received intradermal injection of microbubble contrast agent. Following the identification and localization of SLNs using contrast-enhanced ultrasound (CEUS), Markers were deployed in the SLNs US-guided. Subsequently, the SLNs with Markers were stained and marked with a suspension of nano-carbon US-guided to assist in intraoperative localization of SLNs. Standard SLNB with methylene blue tracing was performed intraoperatively to assess the consistency between the two methods of SLNs localization, thereby determining the ability and accuracy of CEUS in identifying and localizing SLNs. A total of 179 patients were included in the final evaluation analysis, in which a microbubble contrast agent was injected subcutaneously in the areolar region. A total of 201 SLNs were identified, with a median of 1 SLN per patient. Each SLN was identified in 157 patients, and two SLNs were identified in 22 patients. Among the 201 SLNs from the 179 patients, the proportion that could be individually matched between CEUS and the blue dye method was 95.5% (192/201), and the consistency evaluation in SLNs identification between CEUS and blue dye staining was excellent (Kappa value = 0.62, P < 0.001). The consistency of identification and localization of SLNs in early breast cancer patients between CEUS and the blue dye method was strong.

Prevalent findings on low-dose CT scan lung cancer screening: a French prospective pilot study.

Despite significant therapeutic advances, lung cancer remains the biggest killer among cancers. In France, there is no national screening program against lung cancer. Thus, in this perspective, the Foch Hospital decided to implement a pilot and clinical low-dose CT screening program to evaluate the efficiency of such screening. The purpose of this study was to describe the prevalent findings of this low-dose CT screening program. Participants were recruited in the screening program through general practitioners (GPs), pharmacists, and specialists from June 2023 to June 2024. The inclusion criteria included male or female participants aged 50 to 80 years, current smokers or former smokers who had quit less than 15 years prior, with a smoking history of over 20 pack-years. Chest CT scans were conducted at Foch Hospital using a low-dose CT protocol based on volume mode with a multi-slice scanner (≥60 slices) without contrast injection. In total, 477 participants were recruited in the CT scan screening, 235 (49%) were males with a median age of 60 years [56-67] and 35 smoke pack-years [29-44] and 242 females (51%) with a median age of 60 years [55-60] and 30 smoke pack-years [25-40]. Eight participants showed positive nodules on CT scan, as a 1.7% rate. 66.7% of diagnosed cancers were in early stages (0-I). It is feasible to implement structured lung cancer screening using low-dose CT in a real-world setting among the general population. This approach successfully identifies most early-stage cancers that could be treated curatively.

Pre-Stroke Frailty Negatively Affects Leptomeningeal Collateral Flow in Proximal Middle Cerebral Artery Occlusion

Introduction: The adequacy of blood flow from the leptomeningeal collaterals is considered one of the most important factors determining the rate of infarct progression and response to acute stroke treatments in the setting of large vessel occlusions. Several patient-related variables, including age, vascular risk factors, and laboratory parameters, have been proposed to explain the interindividual variability of collateral flow among stroke patients. This study aimed to assess how pre-stroke frailty, an aging-related syndrome characterized by a loss in the physiologic reserve of numerous body functions, affected the degree of leptomeningeal collateral flow in the setting of acute ischemic stroke. Methods: A consecutive series of patients presenting with proximal middle cerebral artery occlusion were enrolled in this prospective, multicenter observational study. Collateral flow was determined by the regional leptomeningeal collateral (rLMC) score on admission computed tomography angiography images. Pre-stroke frailty was assessed by the Edmonton Frailty Scale (EFS), based on the information obtained from patients or their next of kin. The relationship between collateral flow and frailty was evaluated by bivariate and multivariate analyses taking into consideration the demographic, clinical, and imaging characteristics of the patients. Results: The study population was comprised of 116 patients (median [interquartile range] age 78 [71–84] years; 60% female). The EFS scores were negatively correlated with the rLMC score (r = −0.264; p = 0.004). A vulnerable or frail (EFS ≥6) status before stroke, higher blood pressure levels at admission, having imaging studies performed at an earlier phase after contrast injection, and presenting with thrombi extending to the proximal half of the M1 portion of the middle cerebral artery were significantly related to poor collateral circulation (rLMC score ≤10). After adjustment for potential confounders in multivariable analyses, a vulnerable/frail status was independently associated with poor leptomeningeal collateral flow (OR: 2.97 [95% CI: 1.15–7.69]; p = 0.025). Conclusion: Our findings highlight that the leptomeningeal collateral flow is also compromised as part of the diminished physiologic reserve characterizing the frailty status in patients with acute ischemic stroke. Future studies are needed to understand how this interplay contributes to the unfavorable clinical outcomes observed in frail patients after stroke.

Feasibility of Non-Invasive Sentinel Lymph Node Identification in Early-Stage NSCLC Through Ultrasound Guided Intra-Tumoral Injection of 99mTc-Nanocolloid and Iodinated Contrast Agent During Navigation Bronchoscopy.

Background: As the first sentinel lymph nodes (SLN) in lung cancer are most likely to harbor metastasis, their non-invasive identification could have a significant role in future treatments. We investigated the feasibility of adding an SLN procedure to a diagnostic navigation bronchoscopy. Methods: Thirty-one patients were included for injection of 99mTc-nanocolloid and an iodinated contrast agent intra-/peritumorally and assessment of tracer dissipation via SPECT and CBCT imaging. Injections were performed endobronchially using a multi-modal catheter (Pioneer Plus), combining radial ultrasound and an angulated retractable needle to place injections under fluoroscopy and real-time ultrasound. Results: The injection of an imaging tracer was feasible in all cases using the catheter. Ultrasound visualized 29/30 tumors, and tracer injection was performed in 100% of patients. An SLN was subsequently identified in 10 out of 31 cases (32.3%) via SPECT/CT imaging. Iodinated contrast agent injection under CBCT imaging prior to 99mTc nanocolloid injection visualized dissipation pathways and enabled needle relocation for subsequent 99mTc-nanocolloid injection. Conclusions: Performing imaging tracer injections with a multi-modal catheter provided safe and local depot placement immediately following diagnostic navigation bronchoscopy. SPECT/CT imaging using 99mTc-nanocolloid showed inconsistent results for SLN identification.

Contrast Kinetics in CT Coronary Angiography

AbstractComputed tomography coronary angiography (CTCA) is a technically demanding radiological investigation that requires adequate opacification of coronary arteries at peak aortic enhancement phase, with minimal or no contrast in the superior vena cava and right-sided cardiac chambers to avoid streak artifacts of dense contrast. Therefore, it is prudent to know about contrast media, contrast kinetics, and contrast injection protocols. This article attempts to describe the essentials of various aspects of contrast media that should be considered for CTCA along with an in-depth analysis of contrast kinetics that every radiologist should know for obtaining adequate opacification of coronary arteries.

Real-time volumetric imaging of cells and molecules in deep tissues with Takoyaki ultrasound.

Acoustic contrast agents and reporter genes play a critical role in allowing ultrasound to visualize blood flow, map molecules and track cellular function in opaque living organisms. However, existing ultrasound methods to image acoustic contrast agents predominantly focus on 2D planar imaging, while the biological phenomena of interest unfurl in three dimensions. Here, we introduce a method for efficient, dynamic imaging of contrast agents and reporter genes in 3D using multiplexed matrix array transducers. Our "Takoyaki" pulse sequence uses the simultaneous scanning of multiple focal points to excite contrast agents with sufficient acoustic pressure for nonlinear imaging while efficiently covering 3D space. Through in vitro experiments, we first show that the Takoyaki sequence produces highly sensitive volume images of gas vesicle contrast agents and compare its performance with alternative imaging schemes. We then establish its utility in cellular imaging in vivo by visualizing acoustic reporter gene-expressing tumors in a mouse model of glioblastoma. Finally, we demonstrate real-time volumetric imaging by tracking the dynamics of fluid motion in brain ventricles after intraventricular contrast injection. Takoyaki imaging enables a more comprehensive understanding of biological processes by providing spatiotemporal information in 3D within the constraints of accessible multiplexed matrix array systems.