Gadolinium-Based Contrast Agents: Updates and Answers to Typical Questions Regarding Gadolinium Use.

Gadolinium-based contrast agents have expanded the diagnostic usefulness and capability of magnetic resonance imaging. Despite their highly favorable safety profile, these agents have been associated with nephrogenic systemic fibrosis in a small number of patients who have advanced kidney disease. Recently, trace amounts of gadolinium deposition in the brain and other organs have been reported after contrast exposure, even in patients with normal renal function. In this review, we provide a brief overview of recent updates and discuss typical clinical situations related to the use of gadolinium-based contrast agents.

Ultrafast Computation of Left Ventricular Ejection Fraction by Using Temporal Intensity Variation in Cine Cardiac Magnetic Resonance.

Cardiac magnetic resonance enables comprehensive cardiac evaluation; however, intense time and labor requirements for data acquisition and processing have discouraged many clinicians from using it. We have developed an alternative image-processing algorithm that requires minimal user interaction: an ultrafast algorithm that computes left ventricular ejection fraction (LVEF) by using temporal intensity variation in cine balanced steady-state free precession (bSSFP) short-axis images, with or without contrast medium. We evaluated the algorithm's performance against an expert observer's analysis for segmenting the LV cavity in 65 study participants (LVEF range, 12%-70%). In 12 instances, contrast medium was administered before cine imaging. Bland-Altman analysis revealed quantitative effects of LV basal, midcavity, and apical morphologic variation on the algorithm's accuracy. Total computation time for the LV stack was <2.5 seconds. The algorithm accurately delineated endocardial boundaries in 1,132 of 1,216 slices (93%). When contours in the extreme basal and apical slices were not adequate, they were replaced with manually drawn contours. The Bland-Altman mean differences were <1.2 mL (0.8%) for end-diastolic volume, <5 mL (6%) for end-systolic volume, and <3% for LVEF. Standard deviation of the difference was ≤4.1% of LV volume for all sections except the midcavity in end-systole (8.3% of end-systolic volume). We conclude that temporal intensity variation-based ultrafast LVEF computation is clinically accurate across a range of LV shapes and wall motions and is suitable for postcontrast cine SSFP imaging. Our algorithm enables real-time processing of cine bSSFP images on a commercial scanner console within 3 seconds in an unobtrusive automated process.

Multidetector Computed Tomography (MDCT) Angiography in the Pre-Procedural Assessment of Patients Undergoing Transcatheter Aortic Valve Replacement.

Transcatheter aortic valve replacement (TAVR) initially emerged as an alternative option to surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis who were considered either inoperable or high-risk for surgery. However, since its advent the role of TAVR has been continuously evolving on the basis of clinical trials which showed that TAVR is non-inferior to SAVR in patients with moderate as well as low-risk for surgery. Because of recent technological advances, multidetector computer tomography (MDCT) is inherently suitable for the pre-procedural assessment of patients being considered for TAVR within a very short imaging time, MDCT can measure the diameter of the aortic annulus, provide detailed information regarding the status of the entire thoracoabdominal aorta, and assess the caliber of the peripheral vasculature used for transcatheter heart valve delivery. This information helps interventionists make optimal pre-procedural decisions and avoid complications. To familiarize non-imaging specialists with the role of MDCT in TAVR, we provide a concise overview of our approach to using this modality for the pre-procedural assessment of TAVR candidates.

Inflammation and Rupture of a Congenital Pericardial Cyst Manifesting Itself as an Acute Chest Pain Syndrome.

We present the case of a 63-year-old woman with a remote history of supraventricular tachycardia and hyperlipidemia, who presented with recurrent episodes of acute-onset chest pain. An electrocardiogram showed no evidence of acute coronary syndrome. A chest radiograph revealed a prominent right-sided heart border. A suspected congenital pericardial cyst was identified on a computed tomographic chest scan, and stranding was noted around the cyst. The patient was treated with nonsteroidal anti-inflammatory drugs, and the pain initially abated. Another flare-up was treated similarly. Cardiac magnetic resonance imaging was then performed after symptoms had resolved, and no evidence of the cyst was seen. The suspected cause of the patient's chest pain was acute inflammation of a congenital pericardial cyst with subsequent rupture and resolution of symptoms.

Comparison of Low-Dose Higher-Relaxivity and Standard-Dose Lower-Relaxivity Contrast Media for Delayed-Enhancement MRI: A Blinded Randomized Crossover Study.

OBJECTIVE: The gadolinium-based MRI contrast agent gadobenate dimeglumine has nearly twice the MR relaxivity of gadopentetate dimeglumine at 1.5 T. The purpose of this study was to determine whether a lower dose (0.1 mmol/kg) of gadobenate dimeglumine can be used to obtain delayed-enhancement MR images comparable to those obtained with a standard dose (0.2 mmol/kg) of gadopentetate dimeglumine. SUBJECTS AND METHODS: In this blinded randomized crossover study, 20 patients with known myocardial infarction underwent two separate delayed-enhancement MRI examinations after receiving 0.1 mmol/kg gadobenate dimeglumine and 0.2 mmol/kg gadopentetate dimeglumine (random administration). The conspicuity of lesion enhancement 5, 10, and 20 minutes after contrast administration was quantified as relative enhancement ratio (RER). RESULTS: With either gadolinium-based contrast agent, damaged myocardium had higher signal intensity than normal remote myocardium (RER > 4) on delayed-enhancement MR images, and the blood RER declined over time after contrast administration. The blood RER was not significantly higher for gadobenate dimeglumine than for gadopentetate dimeglumine at 5 and 10 minutes. Nevertheless, there was a larger reduction in blood RER for gadobenate dimeglumine than for gadopentetate dimeglumine between 5 and 10 minutes and between 10 and 20 minutes. The volumes of enhancement were similar for gadobenate dimeglumine (13.6 ± 8.8 cm(3)) and gadopentetate dimeglumine (13.5 ± 8.9 cm(3)) (p = 0.98). The mean difference in Bland-Altman analysis for delayed-enhancement volume between the agents was 0.1 cm(3). CONCLUSION: Qualitatively and quantitatively, delayed-enhancement MR images of ischemic myocardium obtained with 0.1 mmol/kg gadobenate dimeglumine are comparable to those obtained with 0.2 mmol/kg gadopentetate dimeglumine 5, 10, and 20 minutes after contrast administration.

Assessment of perfusion and wall-motion abnormalities and transient ischemic dilation in regadenoson stress cardiac magnetic resonance perfusion imaging.

Vasodilator first-pass stress cardiac magnetic resonance perfusion imaging [stress cardiac magnetic resonance (CMR)] is a reliable, noninvasive method for evaluating myocardial ischemia; however, it does not routinely evaluate metrics such as wall-motion abnormality (WMA) and transient ischemic dilation (TID). Using the new selective A2A adenosine receptor agonist regadenoson, we tested a novel protocol for assessing perfusion defects, WMA, and TID in a single stress CMR session. We evaluated 29 consecutive patients who presented for clinically indicated regadenoson stress CMR. Immediately before and after the regadenoson stress perfusion sequence, we obtained baseline and post-stress cine images in the short-axis orientation to detect worsening or newly developed WMAs. This approach also allowed evaluation of TID. Delayed-enhancement imaging was performed in the standard orientations. All patients tolerated the procedure well. Thirteen patients (45 %) had perfusion abnormalities, and four patients developed TID. Seven patients had WMAs, and three of them also had TID. Patients with TID ± WMAs had multivessel disease documented by coronary angiography. By using regadenoson to assess myocardial ischemia during stress CMR, perfusion defects, WMAs, and TID can be evaluated in a single imaging session. To our knowledge, we are the first to describe this novel approach in a vasodilator stress CMR study.

Endovascular repair of the ascending aorta: when and how to implement the current technology.

BACKGROUND: The purpose of our study was to examine when and how to implement the current endoluminal stent graft technology to treat ascending aortic disease. METHODS: During a 7-year period (March 2006 through July 2013), 7 consecutive patients (median age, 69 years; range, 61.5 to 80.5 years) with multiple comorbidities underwent endoluminal repair of the ascending aorta. Six had an ascending aortic pseudoaneurysm, and 1 had iatrogenic coarctation. The median number of prior sternotomies was 2 (range, 1 to 4). RESULTS: Technical success was achieved in all but 1 patient, with 1 death (14.3%) at 30 days. The endoluminal technology used included the Gore TAG (W.L. Gore and Associates, Flagstaff, AZ) thoracic graft (including the new C-TAG) in 6 patients, the Talent stent graft (Medtronic, Santa Rosa, CA) in 1, an Excluder cuff (W.L. Gore) in 2, and an Amplatzer occluder (AGA Medical Corp, Plymouth, MN) in 1. More than 1 stent was placed in 4 patients. Three patients required innominate artery stenting, and 1 required additional left common carotid artery stenting. One patient (14.3%) required intraoperative conversion to open surgical repair. Median follow-up was 14.4 months (interquartile [25th to 75th percentile] range, 5.5 to 22.6 months) with 66.6% overall survival. No aortic-related death was reported during the follow-up period. CONCLUSIONS: Stent grafting of the ascending aorta is feasible but limited and is reserved for high-risk individuals. Technical expertise is essential, and follow-up is mandatory. Technical points, tips, and challenges of the current endovascular technology to effectively treat the ascending aorta are described.

Acute type I aortic dissection: traditional versus hybrid repair with antegrade stent delivery to the descending thoracic aorta.

OBJECTIVE: We compared the short-term outcomes between patients who had undergone classic repair for type I aortic dissection and those who had undergone concomitant antegrade stenting in the descending thoracic aorta. METHODS: From January 2005 to December 2012, 112 patients were treated for acute type I aortic dissection. Eighty-seven patients (group A) underwent traditional operations on the ascending and proximal arch (n = 79, 90.8%), total arch (n = 7, 8.1%), or ascending aorta (n = 1, 1.2%). Twenty-five patients (group B) underwent ascending and proximal arch repair and antegrade stent grafting in the descending thoracic aorta. Various concomitant procedures were performed in both groups. The circulatory arrest times were similar between the 2 groups. RESULTS: The 30-day mortality was 13.8% (n = 12) in group A and 12% (n = 3) in group B. Nine patients in group A (10.3%) and 3 in group B (12%) experienced a postoperative stroke. In group A, 1 patients (1.5%) developed transient spinal cord ischemia, and in group B, 2 patients had transient paraparesis (8.0%). Preoperatively, 24 group A patients and 19 group B patients had malperfusion; this condition resolved postoperatively in 13 group A patients (54.2%) and 16 group B patients (84.2%; P < .037). Eight group A patients (10.8%) and 1 group B patient (4.5%) underwent additional postoperative procedures on the thoracoabdominal aorta a median of 776.5 days (range, 168.5-1102.0) and 54 days postoperatively, respectively. CONCLUSIONS: Antegrade endovascular grafting of the descending thoracic aorta during repair of acute type I aortic dissection is technically safe, does not increase the circulatory arrest time, and could help patients with preoperative malperfusion. Long-term follow-up data are needed.

Low-permeability Gore Excluder device versus the original in abdominal aortic aneurysm size regression.

We sought to compare the efficacy of a low-permeability version of the Gore Excluder™ device with that of the original device. We used volumetric analysis and maximum transverse diameter measurements to examine abdominal aortic aneurysm size regression after endovascular aneurysm repair.From November 2002 through April 2007, 101 patients (82% men; mean age, 71.5 ± 8.9 yr) underwent endovascular aneurysm repair with the Excluder stent-graft: 34 with the original device, and 67 with the low-permeability device. Only patients without endoleak and with preprocedural and 1- and 2-year follow-up computed tomographic scans were included. Eight patients with type II endoleak and 2 with type I endoleak were excluded. Maximum abdominal aortic aneurysm diameter and volume were measured before endovascular aneurysm repair and annually thereafter. Postprocessing, multiplanar computed tomography, and 3-dimensional reconstructions were compared with baseline measurements. Diameter and volume changes that were greater than 5 mm or that exceeded 10% were considered significant.At 12 months, the mean maximum transverse diameter had decreased by -0.16 ± 12.1 mm in recipients of the original device and by -4.8 ± 5.9 mm in recipients of the low-permeability device (P = NS). In addition, mean reduction in volume had changed by -17 ± 16 mL in original-device recipients and by -36.1 ± 37.9 mL in low-permeability device recipients (P < 0.01).One-year follow-up revealed that the low-permeability stent-graft resulted in a greater decrease in abdominal aortic aneurysm volume than did the original stent-graft.

A randomized study of transendocardial injection of autologous bone marrow mononuclear cells and cell function analysis in ischemic heart failure (FOCUS-HF).

BACKGROUND: Autologous bone marrow mononuclear cell (ABMMNC) therapy has shown promise in patients with heart failure (HF). Cell function analysis may be important in interpreting trial results. METHODS: In this prospective study, we evaluated the safety and efficacy of the transendocardial delivery of ABMMNCs in no-option patients with chronic HF. Efficacy was assessed by maximal myocardial oxygen consumption, single photon emission computed tomography, 2-dimensional echocardiography, and quality-of-life assessment (Minnesota Living with Heart Failure and Short Form 36). We also characterized patients' bone marrow cells by flow cytometry, colony-forming unit, and proliferative assays. RESULTS: Cell-treated (n = 20) and control patients (n = 10) were similar at baseline. The procedure was safe; adverse events were similar in both groups. Canadian Cardiovascular Society angina score improved significantly (P = .001) in cell-treated patients, but function was not affected. Quality-of-life scores improved significantly at 6 months (P = .009 Minnesota Living with Heart Failure and P = .002 physical component of Short Form 36) over baseline in cell-treated but not control patients. Single photon emission computed tomography data suggested a trend toward improved perfusion in cell-treated patients. The proportion of fixed defects significantly increased in control (P = .02) but not in treated patients (P = .16). Function of patients' bone marrow mononuclear cells was severely impaired. Stratifying cell results by age showed that younger patients (≤60 years) had significantly more mesenchymal progenitor cells (colony-forming unit fibroblasts) than patients >60 years (20.16 ± 14.6 vs 10.92 ± 7.8, P = .04). Furthermore, cell-treated younger patients had significantly improved maximal myocardial oxygen consumption (15 ± 5.8, 18.6 ± 2.7, and 17 ± 3.7 mL/kg per minute at baseline, 3 months, and 6 months, respectively) compared with similarly aged control patients (14.3 ± 2.5, 13.7 ± 3.7, and 14.6 ± 4.7 mL/kg per minute, P = .04). CONCLUSIONS: ABMMNC therapy is safe and improves symptoms, quality of life, and possibly perfusion in patients with chronic HF.