Contrast Medium Dose Research Articles

Contrast-enhanced Mammography: How Does It Work?

Contrast-enhanced mammography (CEM) is an imaging technique that uses iodinated contrast medium to improve visualization of breast lesions and assessment of tumor neovascularity. Through modifications in x-ray energy, high- and low-energy images of the breast are combined to highlight areas of contrast medium pooling. The use of contrast material introduces different workflows, artifacts, and risks related to the contrast medium dose. In addition, the need to acquire multiple images in each view introduces different workflows, artifacts, and risks associated with the radiation dose. Although CEM and conventional mammography share many underlying principles, it is important to understand how these two mammographic examinations differ and the mechanisms that facilitate image contrast at CEM. ©RSNA, 2021.

Cardiac Computed Tomography versus 3D-Transesophageal Echocardiography in Preprocedural Planning of Left Atrial Appendage Closure

Aim: Preprocedural imaging of the left atrial appendage (LAA) plays a crucial role in the process of LAA closure (LAAC). This study aimed to compare the influence of preprocedural planning of the LAAC with 3D-transesophageal echocardiography (TEE) and cardiac computed tomography (CCT) versus 3D-TEE alone in patients who underwent LAAC with an Amplatzer Cardiac Plug or Amulet. Materials and Methods: In a retrospective study, 176 patients received a preprocedural 3D-TEE and CCT and 167 patients a 3D-TEE only. Both groups had similar patient characteristics and indications for LAAC. Results: There was no difference in terms of procedural success, procedure time, amount of contrast medium, fluoroscopy time, or radiation dose. Patients with CCT/3D-TEE had a longer hospital stay on average. Besides, there was a different incidence of renal diseases (49% for 3D-TEE versus 27% for CCT/3D-TEE; p < 0.001). The number of periprocedural adverse events was comparable. A device-related thrombus occurred three times in each group, and the peri-device leaks reported were similar. Conclusion: A preprocedural CCT does not decrease major adverse events or improve outcome in patients undergoing LAAC.

Optimization of contrast medium volume for abdominal CT in oncologic patients: prospective comparison between fixed and lean body weight-adapted dosing protocols

BackgroundPatient body size represents the main determinant of parenchymal enhancement and by adjusting the contrast media (CM) dose to patient weight may be a more appropriate approach to avoid a patient over dosage of CM. To compare the performance of fixed-dose and lean body weight (LBW)-adapted contrast media dosing protocols, in terms of image quality and parenchymal enhancement.ResultsOne-hundred cancer patients undergoing multiphasic abdominal CT were prospectively enrolled in this multicentric study and randomly divided in two groups: patients in fixed-dose group (n = 50) received 120 mL of CM while in LBW group (n = 50) the amount of CM was computed according to the patient’s LBW. LBW protocol group received a significantly lower amount of CM (103.47 ± 17.65 mL vs. 120.00 ± 0.00 mL, p < 0.001). Arterial kidney signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) and pancreatic CNR were significantly higher in LBW group (all p ≤ 0.004). LBW group provided significantly higher arterial liver, kidney, and pancreatic contrast enhancement index (CEI) and portal venous phase kidney CEI (all p ≤ 0.002). Significantly lower portal vein SNR and CNR were observed in LBW-Group (all p ≤ 0.020).ConclusionsLBW-adapted CM administration for abdominal CT reduces the volume of injected CM and improves both image quality and parenchymal enhancement.

Reducing contrast medium dose with low photon energy images in renal dual-energy spectral CT angiography and adaptive statistical iterative reconstruction (ASIR)

To evaluate the value of using low energy (keV) images in renal dual-energy spectral CT angiography (CTA) and adaptive statistical iterative reconstruction (ASIR) to reduce contrast medium dose. 40 patients with renal CTA on a Discovery CT750HD were randomly divided into two groups: 20 cases (Group A) with 600 mgI kg-1 and 20 cases (Group B) with 300 mgI kg-1. The scan protocol for both groups was: dual-energy mode with mA selection for noise index of 10 HU, pitch 1.375:1, rotating speed 0.6 s/r. Images were reconstructed at 0.625 mm thickness with 40%ASIR, Group A used the conventional 70keV monochromatic images, and Group B used monochromatic images from 40 to 70 keV at 5 keV interval for analysis. The CT values and standard deviation (SD) values of the renal artery and erector spine in the plain and arterial phases were measured with the erector spine SD value representing image noise. The enhancement degree of the renal artery (ΔCT = CT(arterial) -CT(plain)), signal-to-noise ratio (SNR=CTrenal-artery/SDrenal-artery) and contrast-to-noise ratio (CNR=(CTrenal-artery-CTerector spine)/SDerector-spine) were calculated. The single factor analysis of variance was used to analyze the difference of ΔCT, SNR and CNR among image groups with p < 0.05 being statistically significant. The subjective image scores of the groups were assessed blindly by two experienced physicians using a 5-point system and the score consistency was compared by the κ test. Contrast medium dose in the 300 mgI kg-1 group was reduced by 50% compared with the 600 mgI kg-1 group, while radiation dose was similar between the two groups. The subjective scores were 4.00 ± 0.65, 4.50 ± 0.60 and 3.70 ± 0.80 for images at 70 keV (600 mgI kg-1 group), 40 keV (300 mgI kg-1 group) and 45 keV (300 mgI kg-1 group), respectively with good consistency between the two reviewers (p > 0.05). The 40 keV images in the 300 mgI kg-1 group had similar ΔCT (469.77 ± 86.95 HU vs 398.54 ± 73.68 HU) and CNR (15.52 ± 3.32 vs 18.78 ± 6.71) values as the 70 keV images in the 600 mgI kg-1) group but higher SNR values (30.19 ± 4.41 vs 16.91 ± 11.12, p < 0,05). Contrast dose may be reduced by 50% while maintaining image quality by using lower energy images combined with ASIR in renal dual-energy CTA. Combined with ASIR and energy spectrum, can reduce the amount of contrast dose in renal CTA.

Contrast agent dose reduction in computed tomography with deep learning using a conditional generative adversarial network

ObjectivesTo reduce the dose of intravenous iodine-based contrast media (ICM) in CT through virtual contrast-enhanced images using generative adversarial networks.MethodsDual-energy CTs in the arterial phase of 85 patients were randomly split into an 80/20 train/test collective. Four different generative adversarial networks (GANs) based on image pairs, which comprised one image with virtually reduced ICM and the original full ICM CT slice, were trained, testing two input formats (2D and 2.5D) and two reduced ICM dose levels (−50% and −80%). The amount of intravenous ICM was reduced by creating virtual non-contrast series using dual-energy and adding the corresponding percentage of the iodine map. The evaluation was based on different scores (L1 loss, SSIM, PSNR, FID), which evaluate the image quality and similarity. Additionally, a visual Turing test (VTT) with three radiologists was used to assess the similarity and pathological consistency.ResultsThe −80% models reach an SSIM of > 98%, PSNR of > 48, L1 of between 7.5 and 8, and an FID of between 1.6 and 1.7. In comparison, the −50% models reach a SSIM of > 99%, PSNR of > 51, L1 of between 6.0 and 6.1, and an FID between 0.8 and 0.95. For the crucial question of pathological consistency, only the 50% ICM reduction networks achieved 100% consistency, which is required for clinical use.ConclusionsThe required amount of ICM for CT can be reduced by 50% while maintaining image quality and diagnostic accuracy using GANs. Further phantom studies and animal experiments are required to confirm these initial results.Key Points• The amount of contrast media required for CT can be reduced by 50% using generative adversarial networks.• Not only the image quality but especially the pathological consistency must be evaluated to assess safety.• A too pronounced contrast media reduction could influence the pathological consistency in our collective at 80%.

Application on different contrast media concentration in the pancreatic CT angiography scanning

Objective To compare the effects of the different contrast media concentration on the visualization of pancreatic arteries using 64-Detector Spiral CT. Methods 120 cases who underwent abdominal enhancement CT scanning were randomly divided into group A ( n = 60) and B ( n = 60). The contrast media concentration was 300 mgI/ml for group A and 370 mgI/ml for group B respectively, both groups shared the same contrast media dose algorithm and injection speed, with 0.5 gI/kg body weight and 4 ml/s respectively. Reformating the pancreatic arteries via MIP (maximum intensity projection), VR (volume rendering) and MPR (multi-planar reconstruction). Results The CT value of the abdominal aortic celiac opening of group B is significantly higher than A ( P < 0.01). The visualization scores of pancreatic arteriesin Group B are significantly higher than A ( P < 0.05). The visualization ratios of pancreatic arteriesin Group Bare higher than A, the differences of AIPDA、PIPDA、DPA、TPA、PMA、CPA between the 2 Groups have statistically significant ( P < 0.05). Conclusion Pancreatic arteries could have a better visualization by using 370 mgI/ml contrast media in pancreatic artery scanning. 摘要： 目的 比较不同浓度对比剂在 64 排螺旋 CT 胰腺动脉检查中的显示效果。 方法 将本院 120 例行腹部增强 CT 检查的患者随机分成 A、B 两组, 每组各 60 例, 分别注射 300 mgI/ml (A组) 和 370 mgI/ml (B组) 2 种浓度对比剂, 对比剂用量算法及注射速度两组一致, 分别为 0.5 gI/kg 体重和 4 ml/s。利用 MIP(最大密度投影)、VR(容积重现技 术)、MPR(多平面重组)等技术来显示胰腺动脉。 结果 B 组腹主动脉腹腔干开口处强化 CT 值明显高于 A 组, 差异 具有统计学意义 ( P < 0.01)。B 组各胰腺动脉显示评分均明显高于 A 组, 差异具有统计学意义( P < 0.05)。B 组各胰腺动脉显示率均高于 A 组, 其中 AIPDA、PIPDA、DPA、TPA、PMA、CPA 的差异具有统计学意义 ( P < 0.05)。 结论 当注射 370 mgI/ml 对比剂检查胰腺动脉时, 胰腺各动脉可获得较好的显示。

Acute Nonsuppurative Sialadenitis After Contrast Material Administration For Computed Tomography Angiography

Introduction: By the use of iodine-containing intravenous contrast agents, sialadenitis rarely occurs with a sudden expansion of the salivary glands. Its pathogenesis is uncertain, but it appears to be the result of an idiosyncratic reaction or accumulation of iodine in the ductal system of the salivary gland. In this article, we aimed to present a case of contrast-induced sialadenitis after an iodine-containing contrast agent. Case Presentation: A sixty-six-year-old male with a history of abdominal aortic aneurysm was referred for CT angiography. The patient had referred to emergency service with mildly tenderness, pain, and swelling in the bilateral submandibular region. Physical examination also revealed mildly enlarged bilateral submandibular glands, with no fever. There was no erythema, ulcer, and no symptom in both oral and oropharyngeal mucosa. The US performed bilateral diffuse homogeneous expansion of the submandibular salivary glands. In the light of clinical and radiological findings, contrast-induced non-suppurative sialadenitis was considered. Conclusion: Non-suppurative sialadenitis is a rare adverse effect of contrast material administration, which true incidence is unknown. Chronic kidney failure and repeated dose of contrast material are risk factors for this complication. We think that this adverse effect deserves more attention, and follow-up, and prevention for recurrence because its long-term importance is unknown yet.

Current Advances in Transcatheter Intervention for Children Born with Congenital Heart Defects: A Review of Literature

This review aims to sum up the improvements witnessed in the field of interventional cardiology during recent times. The last decade has witnessed significant technical advances in the field of radiological imaging and also in interventional cardiology which has helped to offer more non-invasive solutions for the management of congenital heart defects. This has resulted from the use of advanced 3-dimensional fusion imaging instead of conventional 2-dimensional angiography, applying interactive real-time enhancement and using computed tomography and Magnetic Resonance Imaging for interventional procedures. Similarly the introduction of next generation devices, have not only improved the final outcome of the procedure but also has helped in reducing the challenges that were faced before and with the initial generation of devices. These advances have helped not only in reducing the radiation exposure, the use of contrast medium dose but also have resulted in improved early survival. The field of neonatal cardiology has advanced at an unprecedented pace. The transcatheter closure of patent ductus arteriosus has evolved over time and now it has been made possible at much lower body weight. Similarly, early use of stents for aortic coarctation has been found effective in some patients, especially when surgical intervention had been denied. The application of the hybrid approach for the management of complex congenital heart defects has also been effectively applied. More recently transcatheter placement of the pulmonary valve has been introduced for severely stenotic and/or regurgitant pulmonary valve in adolescents and adults. It is anticipated that in near future, this procedure would be available for relatively younger patients. In conclusion: last 2 decades have improvised pediatric interventional cardiology to incorporate less invasive solutions for CHD. The current advances in radio-diagnostic imaging, gadgetry and technical expertise have improved significantly and led to manage many of such defects by trans-catheter approach. This has led also, to replace the early surgical intervention with a more subtle hybrid approach, thus reducing not only the major surgical trauma but also been found to be cost-effective due to a shorter hospital stay. But a learning curve for performers is required for optimum results and also such procedures should be performed in a fully developed facility with an optimum surgical backup.

A Simple Technique to Perform Endovascular Repair of Abdominal Aortic Aneurysms with a Very Low Dose of Iodine Contrast Media

Iodinated contrast media (ICM) dose is a major factor for postoperative acute kidney injury (AKI) in patients with severe chronic kidney disease (glomerular function rate [GFR] <30 mL/min) during endovascular aortic repair (EVAR). Fusion imaging in hybrid rooms and carbon dioxide angiography represent alternatives but are limited by significant cost and availability. We here describe a simple technique allowing EVAR with a limited ICM dose (<5 mL). Using a standard C-arm, the lowest renal artery and the hypogastric arteries are blindly catheterized based on noncontrast pre-operative imaging (duplex-scan associated with noncontrast computed tomography scan and/or magnetic resonance angiography). An injection of diluted ICM (1 mL ICM + 4 mL saline) can be performed to confirm the correct catheterisation and angiography catheters are let in place as landmarks. Ten patients with GFRs between 17 and 29 ml/min were successfully treated using these tips (median ICM = 3 mL) without postoperative AKI and satisfactory mid-term results.

Evaluating the Association between Contrast Medium Dosage and Acute Kidney Injury in Transcatheter Aortic Valve Replacement Using Different Predictive Models.

Recent studies have suggested that contrast medium (CM) volume is associated with acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR). However, in a high-risk elderly TAVR population, the prognostic value and ideal threshold of CM dosage for AKI is unclear. Data of 532 successive TAVR patients (age 81.1 ± 6.8 years, EuroSCORE II 4.8% ± 6.0%) were therefore retrospectively analyzed. Based on a recently published formula, the renal function (preprocedural serum creatinine: SCr) corrected ratio of CM and body weight (CM*SCr/BW) was calculated to determine the risk of postprocedural contrast-associated AKI. AKI occurred in 94 patients (18.3%) and significantly increased 1-year all-cause mortality (23.4% vs. 13.1%; p = 0.001). A significant correlation between AKI and 30-day as well as 1-year all-cause mortality was observed (p = 0.001; p = 0.007). However, no association between CM dosage or the CM*SCr/BW ratio with the occurrence of AKI was seen (p = 0.968; p = 0.442). In our all-comers, all-access cohort, we found no relationship between CM dosage, or the established risk ratio model and the occurrence of postprocedural AKI. Further research needs to be directed towards different pathophysiological causes and preventive measures as AKI impairs short- and long-term survival.

4D Digital Subtraction Angiography for the Temporal Flow Visualization of Intracranial Aneurysms and Vascular Malformations

PurposeTo assess the benefit and radiation dose of four-dimensional (4D) digital subtraction angiography (DSA) - a time resolved three-dimensional (3D) DSA application - to evaluate the flow and architecture of aneurysms and vascular malformations. MethodsAll patients with cerebrovascular disease were considered who underwent 4D-DSA at our institution between January 2015 and February 2016. For the aneurysm patients, we evaluated the image quality in terms of the visualization of contrast flow in the aneurysm on a 3-point scale (excellent, fair and poor). Interrater agreement between two raters was estimated using Cohen's Kappa statistics. For the shunt disease patients, the additional information obtained from the 4D-DSA was described for each disease. The median radiation dose and volume of contrast medium required for the acquisitions were estimated. ResultsA total of 173 patients underwent 4D-DSA; 126 intracranial aneurysms, 10 arteriovenous malformations (AVM), 15 dural arteriovenous fistula (dAVF) and 22 other diseases. For aneurysm patients, excellent and fair visualization of the intra-aneurysmal flow was observed in 27.7%, 72.3%, and excellent (κ = 0.9) agreement between the raters was found. For AVM and dAVF patients, 4D-DSA clarified the complex vasculature by viewing the discrete time phase of contrast filling. Median radiation dose for intracranial lesions was 79.6 mGy for 6s 4D-DSA, and 175 mGy for 12s 4D-DSA. The median amount of contrast medium used was 18.0 ml for 6s 4D-DSA and 21.0 ml for 12s 4D-DSA. Conclusions4D-DSA provided additional information regarding intra-aneurysmal flow and contributed to detect different component of nidus or shunt points.

Efficacy of three-dimensional road mapping by fusion of computed tomography angiography and fluoroscopy in endovascular treatment of aorto-iliac chronic total occlusion.

The efficacy of multimodality image fusion road-mapping technique for endovascular therapy has been reported recently. Our aim was to evaluate the efficacy of endovascular therapy (EVT) with three-dimensional (3D) road mapping by fusing computed tomography (CT) and angiographical volumetric data for aorto-iliac chronic total occlusion (CTO). We retrospectively analyzed 36 patients with aorto-iliac CTO from June 2017 to November 2019 and classified them into two groups: EVT using a CT fused 3D roadmap (CTf3D-RM; 3D group, n = 14) and standard EVT (standard group, n = 22). Primary endpoint was wiring time and secondary endpoints were procedural success rate, number of guidewires, procedure time, radiation dose, contrast medium dose, and complications. Wiring time was significantly shorter in the 3D group than the standard group (3D, 15.6 ± 10.23min vs. standard, 44.6 ± 35.3min; p = 0.0052). Both groups had high procedural success rates (3D, 100% vs. standard, 100%) and low complication rates (3D, 0.0% vs. standard, 9.1%; p = 0.51). There were significantly fewer guidewires in the 3D group than the standard group (3D, 2.78 ± 1.31 vs. standard, 4.36 ± 2.01; p = 0.0138). The 3D group trended towards shorter procedural time (3D, 78.8 ± 32.5min vs. standard, 107.5 ± 52.5min; p = 0.076), lower radiation dose (3D, 28.6 ± 18.9 Gycm2 vs. standard, 48.9 ± 49.2 Gycm2; p = 0.15), and lower contrast medium dose (3D, 102.2 ± 30.6 vs. standard, 127.5 ± 51.3; p = 0.11) than the standard group. Therefore, we concluded that EVT with CTf3D-RM is effective for aorto-iliac CTO. This method may improve the quality of aorto-iliac CTO interventions.

Feasibility of combined ECG-Gated and Helical acquisition mode in a pre-TAVI computed tomography angiography protocol using a fixed low-volume contrast medium injection

BackgroundTo investigate the feasibility, image quality, and clinical implications of a combined ECG-gated and helical acquisition mode in a computed tomography angiography (CTA) protocol in patients scheduled for transcatheter aortic valve implantation (TAVI) using a fixed, low-volume, contrast medium injection. MethodsBetween July and October 2019, 43 TAVI candidates underwent investigation with CTA using a 64-slice CT scanner. Images obtained were prospectively evaluated. 65 mL of low iodine dose contrast medium (CM), followed by 25 mL of saline, were administered using a fixed multiphasic injection protocol in all patients. Patients were divided into three groups based on BMI: Group 1 (n = 9) with BMI < 22 kg/m2; Group 2 (n = 22) with BMI 22−29 kg/m2; Group 3 (n = 12) with BMI > 29 kg/m2. Images were evaluated for image quality, vessel attenuation (HU), Signal-to-Noise Ratio (SNR), Contrast-to-Noise Ratio (CNR) and estimated radiation dose. Image quality of the aortic root and iliac-femoral vessels was diagnostic in all patients. ResultsVascular attenuation was > 200 HU and CNR > 3 at all vessel levels. ConclusionData from our study suggest that it is possible to image the aortic annulus and aorto-iliac anatomy and obtain high image quality in all patients by using a combined ECG-gated and helical acquisition mode in a computed tomography angiography (CTA) protocol with a fixed low-volume contrast medium injection (65 mL). This allows for accurate CT measurements of the aortic annulus, recruitment of patients for TAVI and facilitates pre-procedural planning in these high surgical risk patients.

Virtual monoenergetic images preserve diagnostic assessability in contrast media reduced abdominal spectral detector CT.

To investigate if low-keV virtual monoenergetic images (VMI40keV) from abdominal spectral detector CT (SDCT) with reduced intravenous contrast media application (RCM) provide abdominal assessment similar to conventional images with standard contrast media (SCM) dose. 78 patients with abdominal SDCT were retrospectively included: 41 patients at risk for adverse reactions who received 44 RCM examinations with 50 ml and 37 patients who underwent 44 SCM examinations with 100 ml of contrast media (CM) and who were matched for effective body diameters. RCM, SCM images and RCM-VMI40keV were reconstructed. Attenuation and signal-to-noise ratio (SNR) of liver, pancreas, kidneys, lymph nodes, psoas muscle, aorta and portal vein were assessed ROIs-based. Contrast-to-noise ratios (CNR) of lymph nodes vs aorta/portal vein were calculated. Two readers evaluated organ/vessel contrast, lymph node delineation, image noise and overall assessability using 4-point Likert scales. RCM were inferior to SCM images in all quantitative/qualitative criteria. RCM-VMI40keV and SCM images showed similar lymph node and muscle attenuation (p = 0.83,0.17), while for all other ROIs, RCM-VMI40keV showed higher attenuation (p ≤ 0.05). SNR was comparable between RCM-VMI40keV and SCM images (p range: 0.23-0.99). CNR of lymph nodes was highest in RCM-VMI40keV (p ≤ 0.05). RCM-VMI40keV received equivalent or higher scores than SCM in all criteria except for organ contrast, overall assessability and image noise, where SCM were superior (p ≤ 0.05). However, RCM-VMI40keV received proper or excellent scores in 88.6/94.2/95.4% of the referring cases. VMI40keV counteract contrast deterioration in CM reduced abdominal SDCT, facilitating diagnostic assessment. SDCT-derived VMI40keV provide adequate depiction of vessels, organs and lymph nodes even at notable CM reduction.

Comparison of four contrast medium delivery protocols in low-iodine and low-radiation dose CT angiography of the aorta

To evaluate contrast medium delivery protocols for the optimal enhancement profile of the aorta with both a reduced dose of radiation and contrast medium, called double-low computed tomography (CT) angiography (DLCTA). DLCTA was performed with 70 kVp and 200 mg iodine/kg in 205 patients following four protocols, namely slow rate (n=52), short duration (n=52), low concentration (n=50), and combined method (n=51), in comparison with a conventional group (120 kVp, 400 mg iodine/kg, n=51). The quantitative measurement of aortic attenuation, homogeneity, and subjective scores were evaluated. Overall, in the four DLCTA groups, the radiation dose was reduced by 62%, and the iodine dose was reduced by 50%. Among the four DLCTA groups, the signal to noise ratio (SNR) and contrast to noise ratio (CNR) of the thoracic aorta were similar, but a significant difference was noted in the abdominal aorta. The short-duration group had the highest peak enhancement, least homogeneity, and worst subjective scores. Good contrast enhancement and good homogeneity were significantly more frequent in the slow-rate (86.6% and 90.4%, respectively) and low-concentration groups (78% and 96.0%, respectively). Subjective scores exhibited a trend of higher scores in the low-concentration group and lower scores in the slow-rate group (p=0.071). DLCTA with 70 kVp and 200 mg iodine/kg is feasible for whole-aortic CT angiography. The low-concentration protocol is recommended owing to its most consistent optimal aortic enhancement profile. Alternatively, the slow-rate protocol can be considered for patients with limited venous access.

Acute Ischemic Strokes of Lesion Segmentation in Ct Angiogram Scans using Roi Pooling

Stroke treatment is time penetrating and up-to-date models for lesion identification involve physical subdivision, a time intense also stimulating method. Automatic segmentation methods extant probabilities of exactly recognizing lesions and refining treatment development. PSPNet, a network architecture which makes utilizes of pyramid pooling to afford worldwide and local contextual info. In this paper, acute ischemic strokes of lesion segmentation which is a process of identification of segmenting lesion as of other substances in therapeutic based images of unexpected loss of blood circulation to the part of blood and thus CT Angiogram scans may routines an dose of contrast material into blood vessels and similarly for analysing and appraise blood vessel disease by RoI pooling which used in object recognition tasks using convolutional neural networks.

Incidencia de nefropatía inducida por contraste tras una tomografía computarizada

Background and aimsThe term contrast-induced nephropathy is used to describe acute deterioration of renal function after the intravenous administration of iodinated contrast material. We aimed to estimate the incidence of contrast-induced nephropathy and to analyze the evolution of different biomarkers of renal function in patients who underwent computed tomography with intravenous contrast administration after premedication with oral hydration and N-acetylcysteine. Material and methodsThis prospective observational study included 112 patients with chronic renal failure (glomerular filtration rate (GFR) 30 mL—60 mL/min/1.73 m2) scheduled for computed tomography with intravenous iodinated contrast material. We recorded demographic variables, dose of contrast material, diabetes mellitus, hypertension, and serum hemoglobin. We measured serum creatinine and GFR after premedication and after the CT examination. We summarized variables as means, standard deviations, and percentages. We used the Wilcoxon and Mann-Whitney tests to compare pre- and post-CT values and Pearson's r to analyze correlations. ResultsIncidence acute kidney injury: 0.9%; 95%CI: 0.36—1.4. Mean difference between pre- and post-CT creatinine: 0.04; 95%CI: 0.002—0.09, p < 0.004. Mean difference between pre- and post-CT GFR: -3.06; 95%CI: -4.66— -1,47), p < 0.001. ConclusionsThe incidence of contrast-induced nephropathy in patients with chronic renal failure and GFR 30 mL—60 mL/min/1.73 m2 is low. The biomarkers of renal function analyzed improve in patients who receive premedication and the minimum dose of contrast material.

Contrast-Sparing Imaging Utilizing Spectral Detector CT for Transcatheter Aortic Valve Replacement Procedure Planning

ABSTRACT Background : Cardiac CTA is an indispensable imaging tool for TAVR procedure planning. Post-processing of the dual-energy CT utilizing dual-source and kV-switching approach enables an increase in the density of iodine and allows the reduction of iodine dose. We hypothesized that the use of a dual-layer Spectral Detector CT (SDCT) can enhance the signal of intravascular iodine contrast material, reduce iodine contrast material volume, and facilitate pre-TAVR planning. Methods : We tested this in a preclinical porcine animal model, with results suggesting that spectral imaging may be superior to conventional imaging even at 21-35% of the full contrast medium dose with regard to reader confidence, higher SNR and CNR at the level of the aortic annulus and root. We subsequently followed this up by a prospective human validation study of 24 patients undergoing TAVR. Results : We demonstrate that SNR and CNR with SDCT were significantly higher (highest in lower energy virtual mono-energetic images (VMI) (monoE 40 keV) compared to conventional images, with the spectral images preferred for procedure planning by an experienced TAVR operator and imaging specialist. This was associated with a reduction in inter-observer variability in TAVR sizing measurements in low dose contrast studies (33% of the full contrast dose) resulting in a higher rate of agreement on the choice of valve prosthesis size. Conclusion : Low contrast dose spectral images achieved similar SNR and CNR compared to full contrast dose conventional images. Taken together, our results suggest that the use of SDCT imaging may facilitate the routine use of low contrast dose as part of pre-TAVR imaging.

CT coronary angiography in asymptomatic male patients with high atherosclerosis risk: Is it justified?

PurposeTo study the necessity of coronary artery screening with computerized tomography coronary angiography (CTCA) in asymptomatic male patients. Material and methodsA total of 226 asymptomatic male patients aged over 50 years were included in this prospective study, according to a clinical protocol approved by the Heraklion University Hospital's Ethics Committee. All participants had at least 3 or more known atherosclerosis risk factors. All patients had none or normal noninvasive cardiological tests in the past and had no contraindications for CTCA. All patients gave their informed consent after being notified regarding contrast medium and radiation dose risks. ResultsSignificant stenoses were found in 52 asymptomatic males (23%). Out of them, 38 male patients underwent invasive coronography and 14 patients were lost in follow-up. In 18 patients, no lesions were found (47.4%). In the other 20 (52.6%) patients, 28 lesions were found. Stent placement was performed in 11 patients, bypass surgery was proposed in 3 patients, and in another 6 patients conservative treatment was suggested. Patients with findings in CTCA were more likely to have a family history of coronary artery disease, compared to patients with normal CTCA (P < 0.05 by using Fischer's Exact Test). Sensitivity of CTCA for significant stenosis was 74.3% with a specificity of 62%. ConclusionCTCA may be used to screen for clinically significant coronary artery disease (CAD) in asymptomatic male patients, particularly those with positive family history or potentially high-risk patients with >3 risk factors for CAD.

Image quality of late gadolinium enhancement in cardiac magnetic resonance with different doses of contrast material in patients with chronic myocardial infarction

BackgroundContrast-enhanced cardiac magnetic resonance (CMR) is pivotal for evaluating chronic myocardial infarction (CMI). Concerns about safety of gadolinium-based contrast agents favour dose reduction. We assessed image quality of scar tissue in CMRs performed with different doses of gadobutrol in CMI patients.MethodsInformed consent was waived for this Ethics Committee-approved single-centre retrospective study. Consecutive contrast-enhanced CMRs from CMI patients were retrospectively analysed according to the administered gadobutrol dose (group A, 0.10 mmol/kg; group B, 0.15 mmol/kg; group C, 0.20 mmol/kg). We calculated the signal-to-noise ratio for scar tissue (SNRscar) and contrast-to-noise ratio between scar and either remote myocardium (CNRscar-rem) or blood (CNRscar-blood).ResultsOf 79 CMRs from 79 patients, 22 belonged to group A, 26 to group B, and 31 to group C. The groups were homogeneous for age, sex, left ventricular morpho-functional parameters, and percentage of scar tissue over whole myocardium (p ≥ 0.300). SNRscar was lower in group A (46.4; 40.3–65.1) than in group B (70.1; 52.2–111.5) (p = 0.013) and group C (72.1; 59.4–100.0) (p = 0.002), CNRscar-rem was lower in group A (62.9; 52.2–87.4) than in group B (96.5; 73.1–152.8) (p = 0.008) and in group C (103.9; 83.9–132.0) (p = 0.001). No other significant differences were found (p ≥ 0.335).ConclusionsGadobutrol at 0.10 mmol/kg provides inferior scar image quality of CMI than 0.15 and 0.20 mmol/kg; the last two dosages seem to provide similar LGE. Thus, for CMR of CMI, 0.15 mmol/kg of gadobutrol can be suggested instead of 0.20 mmol/kg, with no hindrance to scar visualisation. Dose reduction would not impact on diagnostic utility of CMR examinations.