Iodinated Contrast Administration Research Articles

Cardiac Electrical and Structural Changes after Iodinated Contrast Media Administration: A Longitudinal Cohort Analysis.

Background: Iodinated contrast is commonly used for radiological procedures, with one dose delivering several hundred-fold the daily requirements needed for normal thyroid hormone production. Risks of excess iodine include incident thyroid dysfunction, which is associated with adverse cardiac outcomes, yet there are no prospective studies investigating the changes in cardiac physiology following iodine contrast administration. This study was conducted to investigate the longitudinal relationships between the amount of iodinated contrast administration and changes in cardiac electrophysiology and structure. Methods: A longitudinal cohort study was conducted with prospectively enrolled participants who received iodine contrast for elective computed tomography or coronary angiography. Serum thyroid function tests, electrocardiograms (EKG), and transthoracic echocardiograms were obtained serially until 36 months. Trends of electrical and structural cardiac changes following iodine contrast administration were assessed using mixed effect models. Results: The cohort was composed of 129 patients (median age, 70 [interquartile range: 63, 75] years; 98% male). Larger amounts of iodine exposure were associated with increases in QRS and QTc durations and decreased ejection fraction (EF), and these associations were still observed for follow-up EF after additionally adjusting for baseline values (the high-iodine contrast group vs. the low-iodine contrast group, -4.23% [confidence interval, -7.66% to -0.79%]). Dose-response analyses also showed lower EF with larger amounts of iodine received; these trends were not significant for the EKG parameters studied. Conclusions: Over a period of up to 36 months, a larger amount of administered iodine contrast was associated with lower EF among participants. Further investigation is needed to elucidate the long-term trends of electrical and structural cardiac function after iodine contrast administration.

Thyroid Dysfunction Risk After Iodinated Contrast Media Administration: A Prospective Longitudinal Cohort Analysis.

Iodinated contrast media (ICM) is a common source of excess iodine in medical settings, given the common use of iodinated radiologic procedures. To determine the long-term risks of thyroid dysfunction following iodinated contrast administration in a prospective study. A longitudinal cohort study was conducted of patients in the U.S. Veterans Affairs medical system who received ICM. Serum thyroid function, thyroid antibody, and inflammatory markers were measured at baseline. Thyroid function tests were repeated at 1 month, 3 months, and every 6 months thereafter until 36 months. Risk of thyroid dysfunction and longitudinal changes in thyroid hormone levels were assessed using mixed effect models. There were 122 participants (median age, 70.0 [IQR 62.2-74.0] years; 98.4% male). At baseline, six subjects had subclinical thyroid dysfunction prior to ICM receipt. During median follow-up of 18 months, iodine-induced thyroid dysfunction was observed in 11.5% (14/122); six (4.9%) developed hyperthyroidism (including one with overt hyperthyroidism) and eight (6.6%) subclinical hypothyroidism. At last follow-up, ten of 20 subjects with thyroid dysfunction (14 new-onset cases and six with preexisting thyroid dysfunction) had persistent subclinical hyperthyroidism or hypothyroidism. There were also subtle changes in thyroid hormones observed longitudinally within the reference ranges in the overall cohort. There is a rare long-term risk of an excess iodine load on thyroid dysfunction even among individuals from an overall iodine-sufficient region, supporting the need for targeted monitoring following iodinated contrast administration.

Acute Kidney Injury in Patients Undergoing Both Right and Left Heart Catheterization with Coronary Angiography Vs Right Heart Catheterization Only

BackgroundRecent studies have challenged the reported causal association between acute kidney injury and iodinated contrast administration, ascribing some cases to changes in renal function that are independent of contrast administration. MethodsWe studied 1779 consecutive patients undergoing right heart catheterization (RHC) at a Veterans Administration Medical Center. We compared the incidence of acute kidney injury and of nephropathy at 3 months in veterans undergoing right and left heart catheterization and coronary angiography (R&LHC) to the incidence of acute kidney injury and of nephropathy at 3 months in patients undergoing RHC only. ResultsThe incidence of acute kidney injury at 3 days was 47 (9.7%) in the R&LHC group and 58 (9.6%) in the RHC group (P = .99). The incidence of nephropathy at 3 months was 115 (17%) in the L&RHC group and 141 (19.2%) in the RHC group (P = 0.31). In a propensity score-paired analysis of 782 patients and after adjustment for baseline characteristics, the odds ratio for acute kidney injury at 3 days among patients undergoing R&LHC was 1.25 (95% confidence interval, 0.65-2.42; P = .50), and the odds ratio for nephropathy at 3 months was 0.69 (95% confidence interval, 0.46-1.04; P = .08). ConclusionThe incidence of changes in creatinine consistent with acute kidney injury at 3 days and of nephropathy at 3 months was not significantly different in patients undergoing R&LHC compared with patients undergoing RHC only. This supports the thesis that not all changes in creatinine after procedures involving administration of contrast are caused by the contrast.

Iodine-Induced Hypothyroidism and Long-Term Risks of Incident Heart Failure.

Background Although most individuals can adapt to a large iodine load and remain euthyroid, hypothyroidism can develop after iodine exposure. Hypothyroidism is associated with adverse cardiovascular consequences, including heart failure. This study was performed to investigate the relationships between iodine-induced hypothyroidism and incident heart failure. Methods and Results This cohort study of the US Veterans Health Administration (1998-2021) included adults aged ≥18 years with a serum thyroid-stimulating hormone (thyrotropin) <60 days of iodine contrast administration, and <1 year of a baseline normal serum thyroid-stimulating hormone. Cox proportional hazards regression ascertained risk of incident heart failure following iodine-induced hypothyroidism, adjusting for age, sex, race and ethnicity, body mass index, and history of coronary heart disease, dyslipidemia, diabetes, and hypertension. Of 45 470 veterans (mean±SD age, 61.1±14.1 years; 88% men), 3361 (7.4%) developed iodine-induced hypothyroidism. Heart failure developed in 5685 (12.5%) individuals over a median follow-up of 3.6 years (interquartile range, 1.9-7.2 years). Adjusted for risk factors, iodine-induced hypothyroidism was associated with increased risk of heart failure, compared with those who remained euthyroid after iodine exposure (adjusted hazard ratio [HR], 1.11 [95% CI, 1.01-1.22]). Women were at greater risk than men (adjusted HR: women, 1.65 [95% CI, 1.13-2.40]; men, 1.08 [95% CI, 0.98-1.19]; P for interaction, 0.02). Conclusions In the largest US study of this topic, hypothyroidism following iodine exposure was associated with an increased risk of incident heart failure, particularly in women. These findings support the need for further research to address the clinical significance of this issue, including the possible sex-specific risks of incident heart failure in more diverse data sets and study populations.

Extrapolation of CT aortic annulus derived diameter/CT aortic annulus area from 2D echocardiography aortic annulus diameter in TAVR: not a reliable tool

Abstract Funding Acknowledgements Type of funding sources: None. Background Computed tomography (CT) aortic annulus area, CT area derived diameter and two-dimensional echocardiography (2D ECHO) diameters are used for valvular sizing in transcutaneous aortic valve replacement (TAVR). According to our previous study, 2D ECHO annulus diameter was smaller in comparison to CT derived diameter (22.6±2.9 vs 25.0±5.5mm, p = 0.013), but both CT aortic annulus area derived diameter/CT aortic annulus and 2D ECHO diameter predicted correct valve size selection with the same accuracy of 79–80%. However, CT requires radiation and iodine contrast administration, which might be the limitation in patients with chronic kidney disease or history of iodine allergy. Purpose To determine if 2D ECHO diameter can be used for reliable estimation of CT area derived diameter/CT aortic annulus area. Methods 139 consecutive patients with favourable outcome of Sapien XT/Sapien S3 TAVR (no more than mild aortic regurgitation, only one valve implanted) were included in the study. 2D ECHO diameter was measured from mid oesophageal three-chamber view (110–135°) just below the anatomical aortic valve annulus. CT aortic annulus was obtained as double oblique plane by manual multiplanar reconstruction of CT dataset, defined by three lowest attachment points of valvular leaflets. Aortic annulus area was measured by manual tracking of lumen contours, area derived diameter as 2*√(area/π). Linear regression analysis between pre-implant CT area derived diameter and 2D ECHO diameter was performed; extrapolated CT annulus area diameter and CT aortic annulus area [π*(d/2)2] were calculated from 2D ECHO diameter. Concordance of valve size selection based on extrapolated CT area derived diameter vs original CT area derived diameter and extrapolated CT aortic annulus area vs original CT aortic annulus area was determined on patients where CT aortic annulus area/annulus derived diameter were falling outside the overlap of the manufacturer recommended ranges for neighbouring valve sizes. Results Significant relationship between CT aera derived diameter and 2D ECHO diameter was found (r=0.720, p&amp;lt;0.001, Fig 1,2). Extrapolated CT area derived diameter would have led to inappropriate size selection in 33/100 more cases (undersizing in 16%, oversizing in 17%), similar to extrapolated aortic annulus area, where both undersizing and oversizing was observed in 18/106 (17%) more cases in comparison to original CT based parameters. Conclusion Extrapolation of CT aortic annulus area/area derived diameter from 2D ECHO diameter is not a reliable tool in valvular sizing for balloon expandable Sapien valve. In patients with chronic kidney disease or history of iodine allergy, three-dimensional (3D) ECHO aortic annulus assessment remains the only viable alternative tool.

Correlation of ureteric jet angle (UJA) with vesicoureteral reflux grade and its assessment as a noninvasive diagnostic parameter to detect vesicoureteral reflux

BackgroundVesicoureteral reflux (VUR) is an essential urogenital entity affecting infants and younger children. Many patients present late with recurrent urinary tract infections (UTIs), which lead to chronic pyelonephritis, renal scarring, and end-stage renal disease (ESRD). This progression in disease adds to significant morbidity and mortality in the paediatric age group. Voiding cystourethrography (VCUG) is the investigation of choice which is an invasive procedure and is related to the risk of ionizing radiation and iodinated contrast administration. Ureteric jet angle (UJA) is a Doppler parameter that can be obtained by measuring the angle between the horizontal axis of the floor of the optimally distended bladder and the Doppler ureteric jet at the ureteral opening into the bladder. The study aimed (1) to investigate the correlation of UJA with VUR grade and (2) to assess the utility of UJA as a noninvasive diagnostic indicator to diagnose VUR as an alternative to VCUG.MethodAll paediatric patients with urinary complaints were evaluated by voiding cystourethrography (VCUG) for assessment of grades of VUR, followed by colour Doppler evaluation of ureteric jets. VCUG interpretations were made.UJA was calculated as the angle between the long axis of the colour Doppler jet and the horizontal axis of the floor of the optimally distended urinary bladder on colour Doppler examination. Ureteric jet angles were recorded on both sides irrespective of the presence of VUR, and data were analysed using SPSS. The correlation coefficient (r) with p value was calculated. The diagnostic efficacy of UJA (58° or more) to detect VUR was assessed by calculating sensitivity, specificity, PPV, NPV, positive LR and negative LR. The AUC was calculated to evaluate the diagnostic efficacy of UJA 58° or more to detect VUR.ResultsIn total, 34 (68 renal units) children (8 months–12 years), including 20 males (M) and 14 females (F), examined. The mean age was 4.96 ± 2.87 years for the total population, including 4.60 ± 2.02 years for boys and 5.47 ± 2.75 years for girls. Twenty-one patients (10 girls and 11 boys) showed VUR on MCUG. Eight patients showed high grades (grade III–V), including seven boys and a girl. The range of UJA in VUR-negative patients was 27–60° with a median angle of 42.03°. VUR-positive patients showed an angle range of 32–71°with a median angle of 62.13°. High-grade VUR was seen in 8 patients with an angle range of 59–84° and a median angle of 76.31°. A positive correlation (r = 0.81) was noted between UJA and VUR grading. The sensitivity and specificity of angle > 58° to detect VUR were 0.66 and 0.92 with PPV 0.93 and NPV 0.63. Yuden’s J value was 58°. The value for the area under the curve was 0.7.ConclusionsPositive linear correlation was seen between UJA and VUR grades with high specificity and positive predictive value. The Diagnostic Utility of UJA 58° as a screening method to detect severe VUR was acceptable and can be further studied with a larger sample size.

Iodine-Induced Hyperthyroidism and Long-term Risks of Incident Atrial Fibrillation and Flutter.

Although iodine-induced hyperthyroidism is a potential consequence of iodinated radiologic contrast administration, its association with long-term cardiovascular outcomes has not been previously studied. To investigate the relationships between hyperthyroidism observed after iodine contrast administration and incident atrial fibrillation/flutter. Retrospective cohort study of the U.S. Veterans Health Administration (1998-2021) of patients age ≥18 years with a normal baseline serum thyrotropin (TSH) concentration, subsequent TSH <1 year, and receipt of iodine contrast <60 days before the subsequent TSH. Cox proportional hazards regression was employed to ascertain the adjusted hazard ratio (HR) with 95% CI of incident atrial fibrillation/flutter following iodine-induced hyperthyroidism, compared with iodine-induced euthyroidism. Iodine-induced hyperthyroidism was observed in 2500 (5.6%) of 44 607 Veterans (mean ± SD age, 60.9 ± 14.1 years; 88% men) and atrial fibrillation/flutter in 10.4% over a median follow-up of 3.7 years (interquartile range 1.9-7.4). Adjusted for sociodemographic and cardiovascular risk factors, iodine-induced hyperthyroidism was associated with an increased risk of atrial fibrillation/flutter compared with those who remained euthyroid after iodine exposure (adjusted HR 1.19, 95% CI 1.06-1.33). Females were at greater risk for incident atrial fibrillation/flutter than males (females, HR 1.81, 95% CI 1.12-2.92; males, HR 1.15, 95% CI 1.03-1.30; P for interaction = .04). Hyperthyroidism following a high iodine load was associated with an increased risk of incident atrial fibrillation/flutter, particularly among females. The observed sex-based differences should be confirmed in a more sex-diverse study sample, and the cost-benefit analysis of long-term monitoring for cardiac arrhythmias following iodine-induced hyperthyroidism should be evaluated.

Rationale and design of the Dynamic Coronary Roadmap for Contrast Reduction (DCR4Contrast) in PCI randomized controlled trial

The clinical and anatomic complexity of patients undergoing percutaneous coronary interventions (PCI) has increased significantly over the past two decades. Contrast induced nephropathy (CIN) significantly impacts prognosis after PCI, therefore minimising the risk of CIN is important in improving clinical outcomes. Dynamic Coronary Roadmap (DCR) is a PCI navigation support tool which may decrease CIN by projecting a virtual coronary roadmap on the moving angiogram, potentially reducing iodinated contrast volume during PCI. The Dynamic Coronary Roadmap for Contrast Reduction trial (DCR4Contrast) is a multi-center, prospective, unblinded, stratified 1:1 randomised controlled trial investigating if DCR use reduces the total contrast volume administered during PCI compared to PCI performed without DCR guidance. DCR4Contrast aims to recruit 394 patients undergoing PCI. The primary endpoint is the total undiluted iodinated contrast volume administered during the PCI, performed with or without DCR. As of November 14, 2022, 346 subjects have been enrolled. The DCR4Contrast study will investigate the potential contrast-sparing effect of the DCR navigation support tool in patients undergoing PCI. By reducing iodinated contrast administration, DCR has the potential to contribute to reduced risk of CIN and thus increase PCI safety.

Non-enhanced abdominal Computed tomography (CT) for demonstration of painful abdominal conditions in patients not candidates for contrast-enhanced study, how does it help?

Background: There is a wide variety of abdominal painful conditions that necessitate computed tomography (CT) imaging; our study was aimed to demonstrate the utility of non-enhanced computed tomography (NECT) of the abdomen as a standalone study to detect the cause of abdominal pain in patients who are not candidates for iodinated contrast administration.

Iodinated Contrast Administration and Risks of Thyroid Dysfunction: A Retrospective Cohort Analysis of the U.S. Veterans Health Administration System.

Background: Iodine-induced thyroid dysfunction is a potential risk among susceptible individuals. Iodinated contrast media is a common source of an acute iodine load used in the health care setting and is frequently required for diagnostic computed tomography scans, coronary angiograms, and other radiologic studies. However, the epidemiologic risks of iodine-thyroid dysfunction have not been fully established in the United States. Methods: This population-based retrospective cohort study used the U.S. Veterans Health Administration database between 1998 and 2021 and included adults aged ≥18 years with a serum thyrotropin (TSH) measurement. Multivariable logistic regression was used to ascertain the risk of incident thyroid dysfunction (defined by repeated measurements of serum thyroid function) following iodine exposure, adjusting for age, sex, race/ethnicity, baseline serum TSH concentration, and duration between baseline and follow-up TSH concentration. Results: The cohort was composed of N = 4,253,119 veterans (mean ± SD = 63.5 ± 14.3 years; 92.9% men; 65.6% non-Hispanic Whites) with 8,729,155 corresponding pairs of serum TSH measurements, from which there were 499,897 TSH pairs with intervening iodine exposure. Thyroid dysfunction occurred in 4.8% of those pairs who had received iodine contrast and 3.6% of those without iodine exposure. Iodinated exposure was associated with an increased risk of thyroid dysfunction (odds ratio [OR] = 1.39, 95% confidence intervals [CI] = 1.37-1.41, p < 0.001) and consistent for all types of serum thyroid dysfunction (overt or subclinical hypo-/hyperthyroidism). Men were at higher risk for the development of thyroid dysfunction than women (men: OR = 1.42, 95% CI = 1.40-1.44; women: OR = 1.16, 95% CI = 1.11-1.21; p-for-interaction <0.001). Conclusions: In this largest analysis of U.S. adults to date, iodine exposure was associated with only clinically small absolute increased risks of thyroid dysfunction, particularly in men. These findings suggest that screening of thyroid function following iodinated contrast administration should be targeted to high-risk individuals.

Iodinated Contrast Enhancement of Breast Cancer on Prone Multidetector Computed Tomography-Preliminary Findings.

Contrast-enhanced breast imaging has gained increasing importance in the diagnosis and management of breast cancer. The aim of this study was to assess breast cancer enhancement after contrast administration on prone multidetector computed tomography (MDCT). This retrospective, unicentric, institutional review board-approved study included patients with newly diagnosed breast cancer who were submitted to contrast-enhanced MDCT in prone position, with image acquisition before and after nonionic iodinated contrast administration. Sixty breast cancer patients aged between 31 and 74 years (mean, 49 years) were included. Most patients (n = 50, 83.3%) had no special type invasive breast carcinoma and luminal subtype (n = 45, 75%). All index breast tumors were identified on prone MDCT. Forty-three cases (70.5%) presented as mass, 13 (21.3%) as nonmass enhancement and 4 (6.6%) as both mass and nonmass enhancement. Mean tumor density was 37.8 HU and 87.9 HU on precontrast and postcontrast images, respectively. Mean contrast enhancement was 50.2 HU (range, 20-109 HU). There were no statistically significant differences in tumor enhancement according to histological type, molecular subtype, nuclear grade, tumor size, or imaging presentation. Our results show that breast cancer usually can be identified and have significant contrast enhancement on prone MDCT images. This method could be used as an alternative when other contrast-enhanced breast imaging methods are not available.

Effect of intravenous iodinated contrast administration on diagnostic ability for osteoporosis using CT attenuation measurement in patients with liver cirrhosis.

To evaluate the influence of intravenous contrast agent on the diagnostic ability for osteoporosis using CT attenuation measurement in patients with liver cirrhosis. This retrospective study was approved by our institutional review board and informed consent was waived. 208 patients with liver cirrhosis (mean age, 61.25 years ± 9.43 [standard deviation]; range, 30-82 years) who underwent both unenhanced and two contrast-enhanced (arterial and venous phase) abdominal dual-energy CT examinations from January 1 to September 1, 2020, were recruited. CT attenuation values were measured in the medullary compartment of vertebral body (L1-L3) and bone mass was determined by the hydroxyapatite concentration obtained in dual-energy spectral CT and used as the reference standard. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic ability of using CT attenuation number in unenhanced, arterial, and venous phases. Area under ROC curve using unenhanced CT attenuation was different from using arterial CT attenuation (p= 0.038) and venous CT attenuation (p = 0.048) to diagnosing osteoporosis. However, there was no significant difference between unenhanced CT attenuation and arterial CT attenuation (p = 0.773) and between unenhanced CT attenuation and venous CT attenuation (p = 0.746) to distinguish low bone mass (osteoporosis or osteopenia). The diagnostic ability for osteoporosis using CT attenuation measurement in contrast-enhanced scans is decreased due to intravenous contrast contamination, however, which had no influence on the diagnostic ability of CT attenuation for low bone mass (osteoporosis or osteopenia). The diagnostic ability of using enhanced CT attenuation values for osteoporosis decreased compared to unenhanced CT attenuation values.

Incidence of Contrast-Associated Acute Kidney Injury in Renal-Competent COVID-19 Patients Undergoing Computed Chest Angiography.

PurposeCOVID-19 infection poses a significant risk of both renal injury and pulmonary embolism, producing a clinical challenge, as the criterion standard examination for pulmonary embolism, computed tomography angiography (CTA), requires the use of nephrotoxic iodinated contrast agents.Our investigation evaluated whether symptomatic COVID-19–positive patients without laboratory evidence of renal impairment are at increased risk for developing contrast-associated acute kidney injury (CA-AKI).MethodAll COVID-19–positive patients undergoing noncontrast chest computed tomography and CTA at an apex tertiary medical center between March 1 and December 10, 2020, were retrospectively evaluated. A total of 258 renal-competent (estimated glomerular filtration rate >30) patients with baseline and 48- to 72-hour postexamination creatinine measurements were identified and analyzed for incidence of acute kidney injury (AKI) meeting the criteria for CA-AKI.ResultsTwenty-five of 191 patients undergoing CTA (13.1%) and 9 of the 67 undergoing noncontrast computed tomography (13.4%) experienced creatinine increases meeting the criteria for CA-AKI. Univariate and multivariate analyses accounting for known AKI risk factors revealed no correlation between iodinated contrast administration and the incidence AKI meeting the criteria for CA-AKI (univariable odds ratio, 0.97 [95% confidence interval, 0.43–2.20]; multivariable odds ratio, 0.97 [95% confidence interval, 0.40–2.36]).ConclusionsRenal-competent COVID-19 patients undergoing chest CTA may not have an increased risk of AKI. Additional studies are needed to confirm this preliminary finding.

Comparison of intraosseous and intravenous iodinated contrast administration for CT imaging in Hispaniolan Amazon parrots (Amazona ventralis).

Establishing and maintaining intravenous access for contrast medium during CT imaging can be difficult in birds due to their small size and thin walled vessels. Intraosseous (IO) catheters are an alternative to intravenous catheters and are often used for fluid or medication administration in birds. To determine the feasibility of IO iodinated contrast enhancement for CT in birds, 10 adult Hispaniolan Amazon parrots (Amazona ventralis) weighing 260-325g, were enrolled in a prospective randomized blinded crossover group study to evaluate the differences in contrast route administration. The parrots underwent pre- and postcontrast CT scans using both routes of contrast administration with a wash-out period of at least 1week between the two methods. Scans were evaluated subjectively for diagnostic quality and objectively with Hounsfield units measured over three organs: the brain, right kidney, and liver. All scans were diagnostic, and there was no statistically significant measurable difference in contrast enhancement between the two methods in any of the three organs. Subjectively, IO catheters were technically more difficult to place, but once in place, they were easier to manipulate for the imaging procedure and provided no complications upon removal. Minimal adverse side effects were noted from the IO catheters. In this small study, IO iodinated contrast administration was comparable in enhancement characteristics to intravenous administration for CT imaging in Hispaniolan Amazon parrots.

The Role of Computed Tomography in Imaging Non-neurologic Disorders of the Head in Equine Patients.

Computed tomography (CT) imaging of the head in equine patients is now commonly performed as CT scanners are more readily available. Head CT has proven valuable in evaluating spatially complex anatomic structures, where radiographic superimposition, or restricted access via endoscopy or ultrasound, limit complete evaluation of the disease process. Head CT has been demonstrated to be incredibly valuable in the evaluation of dental and paranasal sinus disease, disease of the hyoid apparatus and ear, and in evaluation of skull trauma. CT is an excellent modality for assessment of both osseous and soft tissue structures; however, evaluation of complex vascular anatomy and determination of tissue viability is limited without the use of contrast agents. Therefore, various contrast agent protocols including intravenous and intraarterial iodinated contrast administration techniques have been established. CT also has limitations in the evaluation of brain and spinal cord disease, for which magnetic resonance imaging (MRI) has major advantages. Head CT images are most commonly evaluated in transverse planes. However, standard multiplanar reconstructions of the head including dorsal and parasagittal planes improve the understanding of spatially complex disease processes. These reconstructions can be crucial for accurate identification of diseased teeth and determination of the extent and severity of osseous and paranasal sinus disease. Head CT examinations are becoming an increasingly important diagnostic tool in the evaluation of horses with head disorders, and CT imaging findings are an important aspect in the clinical decision-making process. The following review discusses the indications, benefits, and technical considerations for the use of computed tomography (CT) in evaluating non-neurologic head pathologies in equine patients.

Fully Ultrasound-Assisted Endovascular Aneurysm Repair: Preliminary Report

Reducing fluoroscopy times and iodine contrast administration during endovascular repair (EVAR) of infrarenal aortic aneurysms remains a challenge. The purpose of this study is to evaluate the preliminary results of a fully ultrasound-assisted EVAR without iodine contrast administration. Twenty-seven consecutive patients underwent an elective intravascular ultrasound (IVUS)-assisted EVAR with final contrast-enhanced ultrasound (CEUS) control of correct aneurysm exclusion. In no case intraprocedural injection of iodine contrast medium was performed. The primary study's end points were the overall duration of the procedure, duration of fluoroscopy, cumulative radiation dose, the length of intraoperative CEUS control, and the comparison of findings between intraoperative CEUS and computed tomography (CT) scan at 1 month. Mean duration of the procedure was 130±35min. Overall duration of fluoroscopy was22±18min. Mean radiation dose was 66mGy (range 24-82). The mean length of CEUS final control was 8±2min. No type I or type III endoleak was detected either at CEUS or at angio-CT scan at 1 month from EVAR. CEUS revealed a type II endoleak in 6 patients (22%), compared to 9 type II endoleaks (33%) detected at angio-CT scan 1 month after the procedure (P=0.5). Fully ultrasound (IVUS and CEUS)-assisted EVAR is safe, feasible, and reliable, completely eliminating the need for iodine contrast medium and reducing the radiation exposure for both patients and surgeons.

Canadian Association of Radiologists Guidance on Contrast-Associated Acute Kidney Injury.

Purpose:Iodinated contrast media is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after iodinated contrast administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow-up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations.Information sources:Published literature, including clinical trials, retrospective cohort series, review articles, and case reports, along with expert opinions from radiologists and nephrologists across Canada.Methods:The leadership of the CAR formed a working group of radiologists and nephrologists with expertise in contrast administration and patient management related to contrast-associated AKI. We conducted a comprehensive review of the published literature to evaluate the evidence about contrast as a cause of AKI, and to inform evidence-based recommendations. Based on the available literature, the working group developed consensus recommendations.Key Findings:The working group developed 21 recommendations, on screening, choice of iodinated contrast media, prophylaxis, medication considerations, and post contrast administration management. The key changes from the 2012 guidelines were (1) Simplification of screening to a simple questionnaire, and not delaying emergent examinations due to a need for creatinine measurements (2) Prophylaxis considerations only for patients with estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m2 (3) Not recommending the routine discontinuation of any drugs to decrease risk of AKI, except metformin when eGFR is less than 30 mL/min/1.73 m2 and (4) Not requiring routine follow up serum creatinine measurements post iodinated contrast administration.Limitations:We did not conduct a formal systematic review or meta-analysis. We did not evaluate our specific suggestions in the clinical environment.Implications:Given the importance of iodinated contrast media use in diagnosis and management, and the low risk of AKI after contrast use, these guidelines aim to streamline the processes around iodinated contrast use in most clinical settings. As newer evidence arises that may change or add to the recommendations provided, the working group will revise these guidelines.

A Grave Initial Presentation of Graves’ Disease in a Patient With Moyamoya

Background: Moyamoya syndrome is chronic stenoocclusive disease involving the intracranial internal carotid arteries and their proximal branches along with an associated condition, such as hyperthyroidism1. The concurrence of moyamoya and Graves’ disease is rare. Ischemic stroke in moyamoya syndrome is postulated to be precipitated by thyrotoxicosis-induced hemodynamic instability. Clinical Case: A 63-year old Korean female with history of moyamoya disease with two prior ischemic strokes, hypertension and type 2 diabetes mellitus presented to the ER with 6 hours of left leg weakness and involuntary arm movements. A code stroke was activated and neurologic examination was notable for left leg paresis and left arm stereotypy. CT head showed loss of gray-white matter differentiation in the right frontal lobe concerning for acute ischemia. CT angiography of the head and neck noted diffuse stenosis of intracerebral vasculature and significant stenosis of the cavernous and supraclinoid portions of the internal carotid arteries. MRI brain later confirmed an acute infarct in the right ACA distribution. Neuroimaging incidentally showed a multinodular goiter with a 1.7 cm right thyroid nodule. Subsequently TSH was obtained and resulted as <0.030 mcIU/mL (0.27-5.00 mcIU/mL) with a reflex FT4 of >7.00 ng/dL (0.6-1.8 ng/dL). A review of her prior TFTs showed biochemical euthyroidism. Due to iodinated contrast administration on admission, RAIU scan was deferred. Thyroid ultrasound showed multinodular goiter with diffuse increased vascularity and multiple TI-RADS 4 and 5 nodules bilaterally. On further questioning, the patient reported tachycardia, diarrhea, weight loss and decreased appetite prior to hospitalization. A diagnosis of Graves’ disease was confirmed with TSI of 70.7 IU/L (0.00-0.55 IU/L). She was started on methimazole 20 mg twice daily and propranolol 20 mg q6h. FT4 downtrend from >7.00 to 3.3 ng/dL at time of discharge. Following four weeks of methimazole 20 mg daily, FT4 normalized to 1.70 ng/dL. The patient chose to continue antithyroidal drug therapy for treatment of Graves’ disease. Conclusion: Thyroid function assessment should be considered when evaluating a patient with moyamoya and acute ischemic stroke. If moyamoya syndrome associated with Graves’ disease is identified, treatment should be aimed at maintenance of euthyroidism. Reference: 1. Scott RM, Smith ER. Moyamoya disease and moyamoya syndrome. N Engl J Med. 2009 Mar 19;360(12):1226-37. Disclaimer: The views expressed herein are those of the authors and do not reflect the official policy or position of Brooke Army Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of the Army, the Department of the Air Force and Department of Defense or the U.S. Government.

Prophylaxis of Contrast-Induced Nephropathy in Intravascular Contrast Computed Tomography Procedures by Use of Low Osmolality Contrast Media and Good Hydration

Consequent to the extended use of intravenous iodinated contrast media, increased adverse effects have been recognized, with Contrast-Induced Nephropathy (CIN) constituting one of the most serious of these adverse effects. The purpose of the current study was to investigate a prophylaxis strategy for reducing the effect of intravenous contrast on the development of CIN. Data were collected from 120 patients who received intravenous iodinated contrast agents during CT procedures. CIN was defined as a relative increase of more than 25% or an absolute increase of ≥ 0.5 mg/dL (44 µmol/L) in serum creatinine levels within 48-72 hours post-CT. Our prophylaxis strategy involved intravenous administration of 500 ml normal saline within one hour before the CT procedure and 3 liters of oral hydration within 12 hours post-CT. Additionally, the volume of administered low osmolality contrast media was based on the weight of the patient. A paired t-test revealed no statistically significant differences in creatinine (t = 0.07, P = 0.942) or urea (t = 0.52, P = 0.608) pre-CT vs. post intravenous iodinated contrast media-enhanced CT. Use of low osmolality contrast media and good hydration pre and post intravenous iodinated contrast administration are effective approaches to the prevention of CIN.

Marine-Lenhart Syndrome: Role of Iodinated Contrast Administration, Case Report and A Review of Literature

Marine-Lenhart Syndrome: Role of Iodinated Contrast Administration, Case Report and A Review of Literature