Nephrogenic systemic fibrosis and the use of gadolinium-based contrast agents

Transillumination method in total knee arthroplasty: new approach with old tools

PURPOSE

In this study, we evaluated the possibility of precise intraoperative localization of the lateral genicular arteries by an orthopaedic surgeon using the transillumination method.

METHODS

Twelve patients underwent cemented TKA with patella-friendly Zimmer Biomet NexGen Legacy Posterior Stabilized prostheses (without patellar resurfacing), seven right knees and five left knees. The mean age of patients in the study group was 66.636 ± 7.003 years. The minimal follow-up period was 13 months (mean-16.363 ± 2.5 months). Functional outcomes were assessed using Knee Society and a specific patellar questionnaire-Kujala Score. Intraoperative detection of insufficient patellar stability and/or patellar maltracking was based on the no-thumb technique. In pre- and postoperative period X-ray investigation, standard standing X-ray and Merchant view were used to evaluate implant position and patellofemoral congruency.

RESULTS

In this study, ten out of twelve knee joints (83.3%) had at least one artery visible by the proposed method in the lateral parapatellar area. Five out of ten knee joints had more than one artery that could be visualized and identified as an arterial vessel. Postoperative Knee Society Score showed significant improvement from a mean 51.181 ± 3.868 to a mean 88.727 ± 3.663. Mean hospital length of stay is 8.545 ± 1.863 days. X-ray assessment using standard anteroposterior, lateral, and Merchant skyline views showed appropriate implant positioning and patellofemoral congruency. The mean Kujala Score in the postoperative period (3 and 6 months) was 67.3 ± 6.75 and 75.6 ± 6.42, respectively.

CONCLUSIONS

Using the proposed transillumination method can help preserve the lateral blood supply to the patella and to avoid devascularized patella-related complications.

TRIAL REGISTRATION

Retrospectively registered on 5 of May 2023, Registration number - 3/3-1757.

Patient safety in magnetic resonance imaging

Image acquisition involves the use of static magnetic fields, field gradients and radiofrequency waves. These elements make the MRI a different modality. More and more centers work with 3.0 T equipment that present higher risks for the patient, compared to those of 1.5 T. Therefore, there is a need for updating for radiology staff that allows them to understand the risks and reduce them, since serious and even fatal incidents can occur. The objective of this work is to present a review and update of the risks to which patients are subjected during the performance of a magnetic resonance imaging (MRI) study.

Vascularity of the early post-natal human distal femoral chondroepiphysis: Quantitative MRI analysis

PURPOSE

Injury to or abnormality of developing distal femoral chondroepiphysis blood supply has been implicated in osteochondritis dissecans development. Progressive decrease in epiphyseal cartilage blood supply occurs in normal development; however, based on animal studies, it is hypothesized that there is greater decrease in regions more prone to osteochondritis dissecans lesions. We aimed to quantify differential regional perfusion of the immature distal femoral chondroepiphysis. We hypothesized there is decreased perfusion in the lateral aspect of the medial femoral condyle, the classic osteochondritis dissecans lesion location.

METHODS

Five fresh-frozen human cadaveric knees (0-6 months old) were utilized. The superficial femoral artery was cannulated proximally and contrast-enhanced magnetic resonance imaging performed using a previously reported protocol for quantifying osseous and soft tissue perfusion. Regions of interest were defined, and signal enhancement changes between pre- and post-contrast images, normalized to background muscle, were compared.

RESULTS

When comparing average normalized post-contrast signal enhancement of whole condyles, as well as distal, posterior, and inner (toward the notch) aspects of the medial and lateral condyles, no significant perfusion differences between condyles were found. In the medial condyle, no significant perfusion difference was found between the medial and lateral aspects.

CONCLUSION

We quantified immature distal femoral chondroepiphysis regional vascularity in the early post-natal knee. In specimens aged 0-6 months, no distinct watershed region was detected. Despite possible limitations, given small sample size, as well as resolution of magnetic resonance imaging and analysis, our results suggest the hypothesized vascular abnormality predisposing osteochondritis dissecans either does not occur universally or occurs after this developmental age.

Quantitative assessment of the vascularity of the skeletally immature patella: a cadaveric study using MRI

PURPOSE

While predominant blood supply to the adult patella enters inferomedially, little is known about skeletally immature patellar perfusion. Improved knowledge of immature patella vascularity can further understanding of osteochondritis dissecans, dorsal defects of the patella and bipartite patella, and help ensure safe surgical approaches. We hypothesized that the immature patella would exhibit more uniform blood flow. The study purpose was to quantify immature patella regional perfusion in comparison with adults.

METHODS

Ten cadaveric knees were utilized (five immature, five mature). The superficial femoral artery was cannulated proximally. Signal enhancement increases were compared from pre- to post-contrast MRI to assess relative arterial contributions to patella regions (quadrants, anterior/posterior, superior/inferior, medial/lateral, and outer/inner).

RESULTS

Quantitative-MRI analysis revealed similar distribution of enhancement between the immature and mature patella. The inferior pole exhibited significantly higher arterial contribution versus superior pole in both immature and mature groups (p = 0.009; both groups), while the inferomedial quadrant had the highest arterial contribution of all quadrants in both groups. The superolateral quadrant demonstrated the lowest arterial contribution in the immature group and second lowest in the adult group. The patella outer periphery had significantly greater arterial contribution than the inner central region in both immature (p = 0.009) and mature (p = 0.009) groups.

CONCLUSION

Distribution of arterial contributions between the immature and mature patella was similar. Our results highlight the importance of inferior and inferomedial blood supply in both immature and mature patellas. These findings have implications for paediatric and adult patients; surgical damage to inferior patellar vessels should be avoided to prevent associated complications.

Practical administration of intravenous contrast media in children: screening, prophylaxis, administration and treatment of adverse reactions

Administration of intravenous contrast media to children is a routine practice at many clinical imaging centers, that can involve special considerations. In this paper, we provide practical information to facilitate optimal performance and oversight of this task. We provide targeted screening questions that can help to identify high-risk pediatric patients for both iodine-based and gadolinium-based intravenous contrast media administration. These include children at risk for allergic-like reactions, thyroid dysfunction, contrast-induced nephropathy, and nephrogenic systemic fibrosis. We make recommendations for addressing "yes" responses to screening questions using risk stratification schema that are specific to children. We also present criteria for selecting children for premedication prior to intravenous contrast administration, and suggest pediatric regimens. Additionally, we discuss practical nuances of intravenous contrast media administration to children and provide a quick-reference table of appropriate treatments with pediatric dosages for adverse contrast reactions.

A Practical Guide to MR Imaging Safety: What Radiologists Need to Know

Magnetic resonance (MR) imaging can provide critical diagnostic and anatomic information while avoiding the use of ionizing radiation, but it has a unique set of safety risks associated with its reliance on large static and changing magnetic fields, high-powered radiofrequency coil systems, and exogenous contrast agents. It is crucial for radiologists to understand these risks and how to mitigate them to protect themselves, their colleagues, and their patients from avoidable harm and to comply with safety regulations at MR imaging sites. Basic knowledge of MR imaging physics and hardware is necessary for radiologists to understand the origin of safety regulations and to avoid common misconceptions that could compromise safety. Each of the components of the MR imaging unit can be a factor in injuries to patients and personnel. Safety risks include translational force and torque, projectile injury, excessive specific absorption rate, burns, peripheral neurostimulation, interactions with active implants and devices, and acoustic injury. Standards for MR imaging device safety terminology were first issued in 2005 and are required by the U.S. Food and Drug Administration, with devices labeled as "MR safe," "MR unsafe," or "MR conditional." MR imaging contrast agent safety is also discussed. Additional technical and safety policies relate to pediatric, unconscious, incapacitated, or pregnant patients and pregnant imaging personnel. Division of the MR imaging environment into four distinct, clearly labeled zones--with progressive restriction of entry and increased supervision for higher zones--is a mandatory and key aspect in avoidance of MR imaging-related accidents. All MR imaging facilities should have a documented plan to handle emergencies within zone IV, including cardiac arrest or code, magnet quench, and fires. Policies from the authors' own practice are provided for additional reference. Online supplemental material is available for this article.

Gadolinium and nephrogenic systemic fibrosis: an update

Nephrogenic systemic fibrosis (NSF) is a multisystem disease seen exclusively in patients with renal impairment. It can be severely debilitating and sometimes fatal. There is a strong association with gadolinium-based contrast agents used in magnetic resonance imaging (MRI). Risk factors include renal impairment and proinflammatory conditions, e.g. major surgery and vascular events. Although there is no single effective treatment for NSF, the most successful outcomes are seen following restoration of renal function, either following recovery from acute kidney injury or following renal transplantation. There have been ten biopsy-proved pediatric cases of NSF, with no convincing evidence that children have a significantly altered risk compared with the adult population. After implementation of guidelines restricting the use of gadolinium-based contrast agents in at-risk patients, there has been a sharp reduction in new cases and no new reports in children. Continued vigilance is recommended: screening for renal impairment, use of more stable gadolinium chelates, consideration of non-contrast-enhanced MRI or alternative imaging modalities where appropriate.

Guidelines and protocols for cardiovascular magnetic resonance in children and adults with congenital heart disease: SCMR expert consensus group on congenital heart disease

Cardiovascular magnetic resonance (CMR) has taken on an increasingly important role in the diagnostic evaluation and pre-procedural planning for patients with congenital heart disease. This article provides guidelines for the performance of CMR in children and adults with congenital heart disease. The first portion addresses preparation for the examination and safety issues, the second describes the primary techniques used in an examination, and the third provides disease-specific protocols. Variations in practice are highlighted and expert consensus recommendations are provided. Indications and appropriate use criteria for CMR examination are not specifically addressed.

SPECT/CT imaging of temperature-sensitive liposomes for MR-image guided drug delivery with high intensity focused ultrasound

The goal of this study was to investigate the blood kinetics and biodistribution of temperature-sensitive liposomes (TSLs) for MR image-guided drug delivery. The co-encapsulated doxorubicin and [Gd(HPDO3A)(H₂O)] as well as the ¹¹¹In-labeled liposomal carrier were quantified in blood and organs of tumor bearing rats. After TSL injection, mild hyperthermia (T=42 °C) was induced in the tumor using high intensity focused ultrasound under MR image-guidance (MR-HIFU). The biodistribution of the radiolabeled TSLs was investigated using SPECT/CT imaging, where the highest uptake of ¹¹¹In-labeled TSLs was observed in the spleen and liver. The MR-HIFU-treated tumors showed 4.4 times higher liposome uptake after 48 h in comparison with controls, while the doxorubicin concentration was increased by a factor of 7.9. These effects of HIFU-treatment are promising for applications in liposomal drug delivery to tumors.

Safety and adverse effects during 24 hours after contrast-enhanced MRI with gadobenate dimeglumine (MultiHance) in children

BACKGROUND

Gadolinium-based MR contrast agents have long been considered safe for routine diagnostic imaging. However, the advent of nephrogenic systemic fibrosis (NSF) among certain patients with severe renal insufficiency has brought the issue of safety into question. Nowhere is safety of greater concern than among children who frequently require multiple contrast-enhanced MRI examinations over an extended period of time.

OBJECTIVE

To retrospectively evaluate the safety of gadobenate dimeglumine for contrast-enhanced (CE) MRI across a range of indications.

MATERIALS AND METHODS

Two hundred pediatric inpatients (age: 4 days to 15 years) underwent CE MRI as part of clinical routine. The children received a gadobenate dimeglumine dose of either 0.05 mmol/kg body weight (liver, abdominal imaging, musculoskeletal imaging, brain and other rare indications) or 0.1 mmol/kg bodyweight (cardiovascular imaging, MR-urography). Young (< 8 years) children with congenital heart disease were intubated and underwent MRA evaluation with controlled ventilation. Monitoring for adverse events was performed for at least 24 h after each gadobenate dimeglumine injection. Depending on clinical necessity, laboratory measurements and, in some cases, vital sign and ECG determinations were made before and after contrast injection. Safety was evaluated by age group, indication and dose administered.

RESULTS

No clinically adverse events were reported among children who had one MRI scan only or among children who had several examinations. There were no changes in creatinine or bilirubin levels even in very young children.

CONCLUSIONS

No adverse events were recorded during the first 24 h following administration of gadobenate dimeglumine in 200 children.

Quantification of the plasma clearance kinetics of a gadolinium-based contrast agent by photoinduced triplet harvesting

The use of gadolinium-based contrast agents (GBCA) is integral to the field of diagnostic magnetic resonance imaging (MRI). Pharmacokinetic evaluation of the plasma clearance of GBCA is required for all new agents or improved formulations, to address concerns over toxicity or unforeseen side effects. Current methods to measure GBCA in plasma lack either a rapid readout or the sensitivity to measure small samples or require extensive processing of plasma, all obstacles in the development and characterization of new GBCA. Here, we quantify the plasma concentration of a labeled analogue of a common clinical GBCA by ligand triplet harvesting and energy transfer. The nonemittive GBCA becomes a "dark donor" to a fluorescent detector molecule, with a lower limit of detection of 10(-7) M in unprocessed plasma. On a time scale of minutes, we determine the plasma clearance rate in the wild-type mouse, using time-resolved fluorescence on a standard laboratory plate reader.

Is administration of gadolinium-based contrast media to pregnant women and small children justified?

The use of gadolinium-based contrast media in pregnant or lactating women has been discouraged at many radiology departments due to the lack of knowledge of the risks for the fetus and the unwillingness to expose neonates to unnecessary drugs. In the present review the current literature and present guidelines regarding the use of gadolinium-based contrast media have been reviewed to validate the justification for their administration to pregnant or lactating women and small children.

Monitoring early tumor response to drug therapy with diffuse optical tomography

Although anti-angiogenic agents have shown promise as cancer therapeutics, their efficacy varies between tumor types and individual patients. Providing patient-specific metrics through rapid noninvasive imaging can help tailor drug treatment by optimizing dosages, timing of drug cycles, and duration of therapy-thereby reducing toxicity and cost and improving patient outcome. Diffuse optical tomography (DOT) is a noninvasive three-dimensional imaging modality that has been shown to capture physiologic changes in tumors through visualization of oxygenated, deoxygenated, and total hemoglobin concentrations, using non-ionizing radiation with near-infrared light. We employed a small animal model to ascertain if tumor response to bevacizumab (BV), an anti-angiogenic agent that targets vascular endothelial growth factor (VEGF), could be detected at early time points using DOT. We detected a significant decrease in total hemoglobin levels as soon as one day after BV treatment in responder xenograft tumors (SK-NEP-1), but not in SK-NEP-1 control tumors or in non-responder control or BV-treated NGP tumors. These results are confirmed by magnetic resonance imaging T2 relaxometry and lectin perfusion studies. Noninvasive DOT imaging may allow for earlier and more effective control of anti-angiogenic therapy.

Nanoplatforms for constructing new approaches to cancer treatment, imaging, and drug delivery: what should be the policy?

Nanotechnology is the design and assembly of submicroscopic devices called nanoparticles, which are 1-100 nm in diameter. Nanomedicine is the application of nanotechnology for the diagnosis and treatment of human disease. Disease-specific receptors on the surface of cells provide useful targets for nanoparticles. Because nanoparticles can be engineered from components that (1) recognize disease at the cellular level, (2) are visible on imaging studies, and (3) deliver therapeutic compounds, nanotechnology is well suited for the diagnosis and treatment of a variety of diseases. Nanotechnology will enable earlier detection and treatment of diseases that are best treated in their initial stages, such as cancer. Advances in nanotechnology will also spur the discovery of new methods for delivery of therapeutic compounds, including genes and proteins, to diseased tissue. A myriad of nanostructured drugs with effective site-targeting can be developed by combining a diverse selection of targeting, diagnostic, and therapeutic components. Incorporating immune target specificity with nanostructures introduces a new type of treatment modality, nano-immunochemotherapy, for patients with cancer. In this review, we will discuss the development and potential applications of nanoscale platforms in medical diagnosis and treatment. To impact the care of patients with neurological diseases, advances in nanotechnology will require accelerated translation to the fields of brain mapping, CNS imaging, and nanoneurosurgery. Advances in nanoplatform, nano-imaging, and nano-drug delivery will drive the future development of nanomedicine, personalized medicine, and targeted therapy. We believe that the formation of a science, technology, medicine law-healthcare policy (STML) hub/center, which encourages collaboration among universities, medical centers, US government, industry, patient advocacy groups, charitable foundations, and philanthropists, could significantly facilitate such advancements and contribute to the translation of nanotechnology across medical disciplines.

Nephrogenic systemic fibrosis: UK survey of the use of gadolinium-based contrast media

AIM

To identify the current practice of administration of gadolinium-based contrast media (Gd-CM) within the UK with respect to the European Society of Urogenital Radiology (ESUR) guidelines on nephrogenic systemic fibrosis (NSF).

MATERIALS AND METHODS

One hundred and fifty-two institutions were contacted to request details regarding the use of Gd-CM at their institution, their awareness of NSF, and of the ESUR guidelines, and their departmental policy on the administration of Gd-CM agents associated with NSF (high-risk agents) in patients with diminished renal function.

RESULTS

Of the 100 institutions that replied, 72% used a cyclic agent as a first-line Gd-CM. The majority of institutions used more than one Gd-CM, and 57% used a high-risk Gd-CM. Seventy percent were aware of the ESUR guidelines, and of the 57% that used a high-risk Gd-CM, 9% did not check renal function at all prior to administration. The course of action of the remaining 48% was varied in patients with diminished renal function with some changing to a low-risk Gd-CM and others electing not to use Gd-CM at all. Five percent continued to use a high-risk Gd-CM with an estimated glomerular filtration rate <30ml/min.

CONCLUSION

The present survey shows that the majority of institutions use a low-risk Gd-CM as a first-line agent; however, a number of institutions do use a high-risk Gd-CM and their course of action for patients with diminished renal function is varied. Given current evidence, it is advisable to use a low-risk Gd-CM, such as a cyclic agent, in patients with diminished renal function.

Near infrared-fluorescent and magnetic resonance imaging molecular probe with high T1 relaxivity for in vivo multimodal imaging

A new gadolinium chelating NIR fluorescent molecular probe increases T(1) relaxivity of water protons, facilitating combined optical and magnetic resonance imaging.

Safety first: Recognizing and managing the risks to child participants in magnetic resonance imaging research

Specialized and up-to-date knowledge is required to identify and manage the risks associated with advanced biomedical research. Additional complexities need to be considered when the research involves infants or young children. In this article, we focus on recent information about the physical risks of pediatric magnetic resonance imaging research and highlight information gaps. With an eye to assisting institutional review boards and researchers, we consider strategies for the management of these risks and formulate key questions aimed at exposing hidden hazards. Institutional review boards should ask these questions, and researchers should bear them in mind as they develop research protocols.

Recommendations for cardiovascular magnetic resonance in adults with congenital heart disease from the respective working groups of the European Society of Cardiology

This paper aims to provide information and explanations regarding the clinically relevant options, strengths, and limitations of cardiovascular magnetic resonance (CMR) in relation to adults with congenital heart disease (CHD). Cardiovascular magnetic resonance can provide assessments of anatomical connections, biventricular function, myocardial viability, measurements of flow, angiography, and more, without ionizing radiation. It should be regarded as a necessary facility in a centre specializing in the care of adults with CHD. Also, those using CMR to investigate acquired heart disease should be able to recognize and evaluate previously unsuspected CHD such as septal defects, anomalously connected pulmonary veins, or double-chambered right ventricle. To realize its full potential and to avoid pitfalls, however, CMR of CHD requires training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, transposition of the great arteries, and after Fontan operations. For these and other complex CHD, CMR should be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients. We provide a table of CMR acquisition protocols in relation to CHD categories as a guide towards appropriate use of this uniquely versatile imaging modality.

Diffusion weighted imaging of pediatric and adolescent malignancies with regard to detection and delineation: initial experience

RATIONALE AND OBJECTIVE

To assess the value of diffusion weighted imaging (DWI) magnetic resonance imaging (MRI) in pediatric and adolescent tumor patients with focus on detection and delineation of malignant tumors of the central nervous system, chest, abdomen, and musculoskeletal system.

MATERIALS AND METHODS

Twenty-nine pediatric and adolescent patients (17 males, 12 females, age, 2 months-20 years, mean age: 8.9 years) with clinically suspected malignant tumors were examined with use of a 1.5-T MR scanner with open bore design without sedation or general anesthesia. DWI images were acquired with a single-shot echo planar imaging (EPI) sequence in free breathing with b-values of 0, 500, and 1000 mm/s(2). Images were assessed by two readers in consensus. Artifacts in DWI were graded as not relevant, acceptable, or nondiagnostic. DWI/apparent diffusion coefficient maps were correlated with T1-weighted post-contrast images, and the detectability and correct delineation of the tumors were graded using a three grade scale.

RESULTS

Free-breathing DWI was successfully performed in all patients. In 27 patients, no relevant artifacts were observed; acceptable artifacts were seen in two patients. In all patients, malignancies were detected both on DWI and T1-weighted gadolinium images. Detection and delineation of tumors were possible in all cases with both sequences; T1-weighted gadolinium imaging was superior to DWI in only three patients. Additionally, small diffusion restricted lymph nodes were detected in three patients.

CONCLUSION

DWI is reliable for the accurate detection and delineation of malignant pediatric and adolescent tumors.