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Brugada syndrome is an inherited cardiac arrhythmia that follows autosomal dominant transmission and can cause sudden death. This paper reported a case of Brugada syndrome in a 43-year-old male patient with no clinical symptoms. Brugada-type 2-ECG changes were accidentally detected. Flecainide test was done and proved positive. Gene analysis revealed a novel missense mutation in the SCN5A gene with a genetic variation of D252N. This novel mutation has not been reported on any genetic databases related to Brugada syndrome. Functional protein analysis software suggested that the mutation occurs in the highly conserved gene and probably has a damaging effect. This is the first Brugada syndrome case reported with a mutation in the SCN5A gene in Vietnam.

Background Little is known about the quality of life (QOL) and health status of adults with congenital heart disease (CHD) in developing countries. Therefore, this study aimed to describe the QOL and health status of hospitalized adults with CHD in Vietnam and investigate the association between QOL and their biological-social characteristics. Methods A cross-sectional study was conducted with 109 adults with CHD, hospitalized in the Vietnam National Heart Institute, between June and December 2019. Validated instruments to assess QOL and health status describing patient-reported outcomes were used, including the EuroQOL-5 Dimensions-5 Level, Satisfaction with Life Scale, and Hospital Anxiety and Depression Scale. Results The mean scores on the EuroQOL-descriptive system (EQ-DS) and EuroQOL visual analogue scale (EQ-VAS) were 0.792 (SD = 0.122, 95% confidence interval [CI] 0.769–0.815) and 66.3 (SD = 12.5, 95% CI 63.9–68.7), respectively. A total of 9.2% (n = 9) patients experienced life dissatisfaction. The prevalence of anxiety and depression were 18.7% (n = 20) and 11% (n = 12), respectively. Scores of QOL in patients aged > 30 years were lower than in those aged ≤ 30 years. Stratified multivariate logistic regression revealed that poor QOL related to being unemployed/unstable employment (OR 4.43, 95% CI 1.71–11.47, p = 0.002), life dissatisfaction associated with unmarried status (OR 4.63, 95% CI 1.2–17.86, p = 0.026), anxiety regarding unemployment/unstable employment (OR 3.88, 95% CI 1.27–11.84, p = 0.017) and complex CHD/PAH (OR 4.84, 95% CI 1.33–17.54, p = 0.016), and depression regarding unemployment/unstable employment (OR 4.63, 95% CI 1.22–17.59, p = 0.003). Conclusions Reduced QOL and elevated psychological problems were common experiences among hospitalized adults with CHD in Vietnam. Biological-social characteristics such as unmarried status, unemployment/unstable employment, and complex CHD/PAH related to poor QOL, life dissatisfaction, anxiety, and depression.

Background: Little is known about the quality of life (QOL) and health status of adults with congenital heart disease (CHD) in developing countries. Therefore, this study aimed to describe the QOL and health status of adults with CHD and investigate the association between QOL and biological and social characteristics of these patients in Vietnam.Methods: A cross-sectional study was performed among 109 adults with CHD, hospitalised in the Vietnam National Heart Institute, between June 2019 and December 2019. Validated instruments to assess QOL and health status describing patient-reported outcomes were used, including the EuroQOL-5 Dimensions-5 Level, Satisfaction with Life Scale and Hospital Anxiety and Depression Scale. The data of QOL and health status were analysed using univariable and multivariable logistic regressions.Results: The overall mean scores on the EuroQOL-descriptive system (EQ-DS) and the EuroQOL visual analogue scale (EQ-VAS) were 79.2 (SD = 12.2, 95% confidence interval, CI: 76.9–81.5) and 66.3 (SD = 12.5, 95% CI: 63.9–68.7), respectively. Symptoms of anxiety and depression were common among adults with CHD (18.7%, n = 20 and 11%, n = 12; respectively). Stratified multivariate logistic regression revealed: poor QOL using the EQ-DS, and that anxiety related to suffering from a complex CHD or pulmonary artery hypertension (OR = 4.55; 95% CI: 1.26–16.4; p = 0.021 and OR = 4.19, 95% CI: 1.2–14.56; p = 0.024; respectively); poor QOL using the EQ-VAS and that anxiety and depression related to being unemployed or having an unstable employment (OR = 4.16, 95% CI: 1.64–10.56, p = 0.003; OR = 3.63, 95% CI: 1.23–10.72, p = 0.02 and OR = 7.68, 95% CI: 2.09–28.25, p = 0.002; respectively); and life dissatisfaction related to being unmarried (OR = 4.63; 95% CI: 1.2–17.86; p = 0.026).Conclusions: Adults with CHD in Vietnam experienced low QOL, and high levels of anxiety and depression. Poor QOL and psychological problems were related to being female, being unmarried, having low educational level, being unemployed or unstably employed, and having complex CHD or pulmonary artery hypertension.

Introduction: In Vietnam, knowledge about renal function in adults with congenital heart disease (CHD) is limited. Hypothesis: This study aims to estimate incidence of renal dysfunction in adults with congenital heart disease and risk factors. Methods: This is a cross-sectional study, including 365 CHD patients more than 16 years old. We collected clinical and para-clinical information, estimated glomerular filtration rate (GFR) and calculated the odds ratio (OR) for reduced GFR. Results: Totally, 52.8% patients had GFR < 90 ml/phút/1.73 m 2 . Logistic regression had confirmed the OR for GFR < 90 ml/phút/1.73 m 2 in the group > 60-years-old, the group with atrial fibrillation, the group with heart failure (based on NT-proBNP > 125 pmol/L), and the group with pulmonary arterial hypertension (based on pulmonary artery systolic pressure > 50 mmHg by echocardiography) were 6.46 (95% CI: 1.37 - 30.41), 7.58 (95% CI: 1.66 - 34.56), 2.98 (95% CI: 1.49 - 5.98) and 1.84 (95% CI: 1.02 - 3.33), respectively. Conclusions: Renal dysfunction is common in adults with CHD. Age > 60 years-old, atrial fibrillation, heart failure, and pulmonary arterial hypertension were risk factors for renal dysfunction in adults with CHD.

Familial hypercholesterolemia (FH) is underdiagnosed and undertreated in a majority of the low- and middle-income countries. FH registries could prove useful in bridging the knowledge gaps, supporting genetic and clinical research, and improving health-care planning and patient care. Here, we report the first usage experience of the Vietnam FH (VINAFH) Registry. The VINAFH Registry was established in 2016 as a long-term database for prospective cohorts. FH patients were detected based on the opportunistic and cascade screening. Diagnosis of FH was assessed using the Dutch Lipid Clinic Network criteria, plasma levels of low-density lipoprotein (LDL) cholesterol, and genetic testing. To date, a total of 130 patients with FH have been registered, with 48 index cases and 82 relatives. Of the 130 patients, 8 were homozygous FH patients and 38 were children. Of FH individuals, 46.7% was confirmed by genetic testing: 61 patients (96.8%) carried the LDLR mutation (c.681C > G, c.1427C > G, c.1187-?_2140 ± ?del, c.2529_2530delinsA), and two patients (3.2%) carried the PCSK9 (protein convertase subtilisin/kexin type 9) mutation (c.42_43insTG). The c.2529_2530delinsA mutation detected in this study is novel and reported only in the Vietnamese population. However, only 53.8% of FH patients were followed up post diagnosis, and only 15.3% of these were approved for lipid-lowering therapy and specialized care. Notably, factors such as knowledge about FH in patients and/or guardians of FH children and support of primary care physicians affected patient participation with respect to treatment strategies and follow-up. Genetic identification, screening, and treatment of FH were feasible in Vietnam. The VINAFH Registry significantly contributed to the formation of the government agencies legislative acts that established the importance of FH as a socially and medically important disease requiring appropriate management strategies. Other low- and middle-income countries could, thus, use the VINAFH Registry model as a reference to establish programs for FH management according to the current status.

Background Multiple studies investigating the use of focused cardiac ultrasound (FCU) in lower and middle-income countries and in medically underserved areas of the United States have demonstrated utility in echocardiographic screening algorithms performed by a variety of operators at different levels of training. No study to date has employed previously untrained nurses in a medically underserved setting to identify older adults with cardiac disorders. The aim of this study was to assess the accuracy of nurse-performed FCU to screen adult subjects at a village health center in Vietnam. Methods Vietnamese nurses (N = 8) underwent structured training conducted by sonographers and physicians during an outreach event sponsored by the American Society of Echocardiography Education and Research Foundation. The nurses were trained to detect abnormalities from a single echocardiographic view (parasternal long-axis) with a laptop-sized device and underwent pre- and posttraining testing. Following training, cardiac ultrasound examinations were performed on subjects >50 years of age at a village health center. First, the nurses performed focused cardiac ultrasound using two-dimensional and color Doppler imaging in the parasternal long-axis view using the M7 device and recorded their assessments. Two-dimensional color and spectral Doppler echocardiography was thereafter performed using the same machine by a sonographer (n = 5) or a Vietnamese echocardiography-trained cardiologist (n = 1). Interviews and electrocardiography were performed at the time of FCU. Results Each nurse improved from pre- to posttraining (average improvement in correct answers, 21%; range, 2%–31%). During the scanning phase, nurses' sensitivity, specificity, and accuracy for identifying subjects with any abnormality were 51.5% (85 of 165), 78.1% (82 of 105) and 61.9%, respectively. There were 60 subjects with significant findings (22.2%); all of these subjects had significant abnormalities visible on parasternal long-axis images. Overall sensitivity, specificity, and accuracy for identifying subjects with major abnormalities were 83.3% (50 of 60), 78.1% (164 of 210), and 78.6%, respectively. Nurse-performed FCU demonstrated much higher sensitivity with lower specificity than electrocardiography alone. The combination of nurse-performed FCU plus ECG identified all of the significant findings on echocardiography and increased accuracy to 91.5%. Conclusions Nurses with no prior echocardiographic experience and with limited training can identify patients with significant cardiac abnormalities using FCU with acceptable accuracy. Screening strategies involving FCU may play a role in improving access to health care and triage in underserved areas.

Background and aims Familial hypercholesterolaemia has not been previously described in the Vietnamese population. We aimed to describe the features of patients with homozygous familial hypercholesterolaemia (hoFH) in Vietnam and the outcomes of screening family members using genetic and cholesterol testing. Methods Mutation testing by massively parallel sequencing for genes causative of FH was undertaken in five index cases presenting to a single cardiac center with a presumptive diagnosis of hoFH. Cascade testing of all available family members was subsequently undertaken. The number of new cases of FH detected and commenced on lipid-lowering treatment was evaluated. Results All five index cases had true homozygous mutations in the LDL receptor gene (LDLR). Cascade screening was undertaken in four families. 107 relatives were screened and FH was identified in 56 relatives (52%), including 3 new cases of hoFH. Only 5 FH relatives (9%) were subsequently treated owing to the adverse perceptions and comparative high cost of drug treatment, and lack of awareness of FH among patients and local doctors. Conclusions HoFH due to LDLR mutations is a severe disorder in Vietnam that needs early detection and treatment with LDL-cholesterol lowering drugs. Cascade testing of families allows effective detection of new cases of FH that may also benefit from early treatment. However, convincing patients to commence statin treatment is a challenge. Extended education and awareness programs and treatment subsidies are imperative to improve the care of patients and families suffering from FH in Vietnam.

Assessment of microembolization after coronary interventions is clinically challenging, thus we longitudinally investigated microemboli effects on moderately ischemic myocardium using MRI and histopathology. Twenty-four pigs (8/group) were divided into: group I (no intervention), group II (45 min LAD occlusion) and group III (45 min LAD occlusion with microembolization). Cine, perfusion and delayed contrast enhanced MRI (DE-MRI), using 1.5T MRI, were used for assessment at 3 days and 5 weeks. Triphenyltetrazolium-chloride (TTC) and Masson-trichrome were used as gold standard references for macro and microscopic quantification of myocardial infarction (MI). Cine MRI showed differential increase in end systolic volume (1.3 ± 0.08 ml/kg group II and 1.6 ± 0.1 ml/kg group III) and decrease in ejection fraction (45 ± 2 and 36 ± 2 %, respectively) compared with controls at 3 days (2.1 ± 0.1 ml ESV and 50 ± 1 % EF, P

Background Patients with acute myocardial infarct (MI) show additional damage after coronary interventions. Purpose To longitudinally quantify structural and functional changes in the left ventricle (LV) subjected to microembolized MI using multidisciplinary computed tomography (MDCT) and independent reference methods. Material and Methods Swine ( n = 20) served as controls (group I) or were subjected to a combination of coronary occlusion, microembolization, and reperfusion and imaged at 3 days (group II) or 3 days and 5 weeks (group III). LV volumes, perfusion, and MI mass were quantified on cine, perfusion, and delayed contrast enhancement (DE) MDCT. MRI, cardiac injury biomarkers, histochemical and histopathologic stains were used as independent references. Results MDCT showed a reduction in ejection fraction and increased end systolic volume (31 ± 2% and 82 ± 3 mL, respectively) of group III compared with I (48 ± 2% and 57 ± 1 mL, respectively). It also demonstrated perfusion deficits in microembolized MI and peri-infarcts. DE-MDCT delineated microvascular obstruction (MVO) zones embedded in acute microembolized MI and microinfarct specks resulting from persistent MVO by deposited microemboli in microvessels of peri-infarct zone. Bland-Altman test showed close agreements between the extents of microembolized MI measured on DE-MDCT, DE-MRI, and histochemical TTC staining, but not between these modalities and microscopy. MI resorption was evident between 3 days and 5 weeks (13.4 ± 0.5 g and 9.8 ± 0.5 g, P Conclusion MDCT can longitudinally quantify regional perfusion deficits, LV dysfunction, and resorption of microembolized MI. MDCT or MRI can be used alternatively after coronary interventions in cases of contraindications for one modality or the other.

Purpose To provide direct evidence that mechanical obstruction of microvessels inhibits infarct resorption (healing) and enhances left ventricular (LV) remodeling using MRI. Materials and Methods Animals (n = 20 pigs) served as controls (group I) or were subjected to either 90 min left anterior descending (LAD) coronary artery occlusion/reperfusion (group II) or 90 min LAD occlusion/ microemboli delivery/reperfusion (group III). MRI (cine and delayed contrast enhanced MRI, DE-MRI) was performed at 3 days and 5 weeks after interventions and used for assessing LV function, mass, and extent of myocardial damage and microvascular obstruction (MVO) using semi-automated threshold method. Results Persistent MVO in the core of contiguous infarct was larger and more frequent (n = 8/8) in group III than group II (4/8) on DE-MRI at 3 days. Furthermore, patchy microinfarct, as a result of microembolization, was visible as hyperenhanced zone at the borders of the contiguous infarct. The reduction in ejection fraction and increase in LV volumes on cine MRI were greater in group III than group II at 3 days and 5 weeks, which may be attributed to the slow infarct resorption, MVO extents and patchy microinfarct at the borders. Conclusion This MRI study illustrates the recently raised conjecture that MVO delays/inhibits infarct resorption (healing), accentuates LV hypertrophy and pathological remodeling. J. Magn. Reson. Imaging 2014;40:906–914. © 2014 Wiley Periodicals, Inc.

To use cardiac magnetic resonance (MR) imaging indices, injury biomarkers, and microscopy for quantifying the effects of defined microemboli volume and sizes on viability, left ventricular (LV) function, and perfusion in preexisting acute myocardial infarcts in a swine model.Institutional approval was obtained to perform x-ray fluoroscopy and 90-minute left anterior descending coronary artery occlusion-reperfusion (single ischemic insult) in 16 pigs and coronary embolization in eight of the 16 pigs (32 mm(3), 40-120 μm microemboli) (double ischemic insults). Another eight pigs served as controls. Cardiac MR imaging results (viability, function, and perfusion), injury biomarkers (creatine-kinase-MB and troponin I), and histopathologic evaluations were quantified. Analysis of variance was performed, and a P value less than .02 was considered to indicate a significant difference.Delayed contrast material-enhanced MR imaging allowed simultaneous visualization of hyperenhanced large infarcts, hypoenhanced microvascular obstruction (MVO) zones, and moderately enhanced patchy microinfarcts in border zones, which represent different degrees of contraction and perfusion in the respective regions, in pigs subjected to double ischemic insults. The increase in myocardial damage was smaller in pigs with double insults (15.7% ± 1.1% of total LV mass) than in those with a single insult (12.4% ± 1.2%, P.02), but the reduction in LV ejection fraction was disproportional (32% ± 0.6% and 38% ± 1%, P.02, respectively). Delayed contrast-enhanced imaging can allow quantification of the MVO zone but can result in underestimation of the extent of myocardial damage compared with microscopy in animals subjected to double insults (18.2 ± 1.6, P.02). A significant increase in cardiac injury biomarkers was observed at 18-24 hours in both cohorts. The additional effect of microemboli on troponin I was demonstrated at 68-72 hours (3.2 ng/mL ± 0.85 [3.20 μg/L ± 0.85] vs 1.34 ng/mL ± 0.43 [1.34 μg/L ± 0.43], P.02).MR imaging has the potential to allow visualization of acute myocardial infarcts, MVO zones, and patchy microinfarcts simultaneously. The accentuated LV dysfunction caused by double ischemic insults was linked to expansion of the MVO zone, perfusion deficits, and myocardial damage.

Purpose To assess the feasibility of a magnetically assisted remote-controlled (MARC) catheter system under magnetic resonance (MR) imaging guidance for performing a simple endovascular procedure (ie, renal artery embolization) in vivo and to compare with x-ray guidance to determine the value of MR imaging guidance and the specific areas where the MARC system can be improved. Materials and Methods In concordance with the Institutional Animal Care and Use Committee protocol, in vivo renal artery navigation and embolization were tested in three farm pigs (mean weight 43 kg ± 2 [standard deviation]) under real-time MR imaging at 1.5 T. The MARC catheter device was constructed by using an intramural copper-braided catheter connected to a laser-lithographed saddle coil at the distal tip. Interventionalists controlled an in-room cart that delivered electrical current to deflect the catheter in the MR imager. Contralateral kidneys were similarly embolized under x-ray guidance by using standard clinical catheters and guidewires. Changes in renal artery flow and perfusion were measured before and after embolization by using velocity-encoded and perfusion MR imaging. Catheter navigation times, renal parenchymal perfusion, and renal artery flow rates were measured for MR-guided and x-ray-guided embolization procedures and are presented as means ± standard deviation in this pilot study. Results Embolization was successful in all six kidneys under both x-ray and MR imaging guidance. Mean catheterization time with MR guidance was 93 seconds ± 56, compared with 60 seconds ± 22 for x-ray guidance. Mean changes in perfusion rates were 4.9 au/sec ± 0.8 versus 4.6 au/sec ± 0.6, and mean changes in renal flow rate were 2.1 mL/min/g ± 0.2 versus 1.9 mL/min/g ± 0.2 with MR imaging and x-ray guidance, respectively. Conclusion The MARC catheter system is feasible for renal artery catheterization and embolization under real-time MR imaging in vivo, and quantitative physiologic measures under MR imaging guidance were similar to those measured under x-ray guidance, suggesting that the MARC catheter system could be used for endovascular procedures with interventional MR imaging. (©) RSNA, 2016.

Background MR-guided focused ultrasound (MRgFUS) might be a very safe and effective minimally invasive technique to treat facet joint pain caused by arthritis and other degenerative changes. However, there are still safety concerns for this treatment and challenges regarding MR imaging and temperature mapping due to susceptibility effects between the bone and soft tissue near the joint, which has resulted in poor MR image quality. The goal of this research was to evaluate multiple magnetic resonance imaging (MRI) pulse sequences for characterizing ablated lumbar facet joint lesions created by high-intensity focused ultrasound (FUS) and compare the findings to histological tissue assessment. In particular, we investigated the use of T2-weighted MRI to assess treatment effects without contrast administration. Methods An IACUC approved study (n = 6 pigs) was performed using a 3T widebore MRI system equipped with an MRgFUS system. Facet joints of the lumbar vertebra were ablated using 1-MHz frequency and multiple sonication energies (300–800 J). In addition to T2-weighted MRI for treatment planning, T1-, T2-, and T2*-weighted and perfusion MRI sequences were applied. Signal intensity ratios of the lesions were determined. Histopathology was used to characterize cellular changes. Results Ablation of the facet joint, using MRgFUS, was successful in all animals. T2-weighted images showed high signal intensity in the edematous facet joint and adjacent muscle, while delayed contrast-enhanced T1-weighted images showed an enhanced ring surrounding the target volume. T2*-weighted GRE images revealed inconsistent lesion visualization. Histopathology confirmed the presence of cellular coagulation (shrinkage), extracellular expansion (edema), and hemorrhage in the bone marrow. Conclusions MRgFUS provided sufficient precision and image quality for visualization and characterization of ablated facet joints directly after ablation. MRI may help in monitoring the efficacy of FUS ablation without contrast after treating patients with back pain.

To quantify, using MRI, the acute impacts of defined volume and sizes of coronary microemboli on myocardial viability and left ventricular (LV) function and to use LAD occlusion/reperfusion, as a reference. A total of 28 farm pigs were used in this study. Eight animals were used as controls. Successful coronary interventions were performed under X-ray fluoroscopy in 16 pigs to induce microinfarct (delivery of 16 mm3 of 40–120 μm) and large infarct (90 min LAD occlusion/reperfusion). On day 3, animals were imaged using contrast enhanced (in beating and non-beating hearts) and cine MRI for evaluating LV viability and function, respectively. Microscopy and cardiac injury enzymes were used to confirm the presence of necrosis. Myocardial damage was smaller after microembolization than occlusion/reperfusion (6.5 ± 0.6 %LV mass vs. 12.6 ± 1.2 %, P < 0.001). The increase in LV end-systolic volume and decreases in ejection fraction, cardiac output and regional systolic wall thickening, however, were comparable between groups, but significantly differed from controls. MRI also demonstrated microvascular obstruction after microembolization and occlusion/reperfusion as hyperenhanced and hypoenhanced regions, respectively. Microscopic examination revealed patchy necrosis, inflammatory cell infiltration, but no intramyocardial hemorrhage after microembolization and extensive intramyocardial hemorrhage and transmural damage in the occlusion/reperfusion group. Cardiac injury enzymes confirmed presence of myocardial damage in animals with interventions. Coronary microemboli have acute impact on LV function compared to control animals. Despite the difference in myocardial damage, global and regional LV dysfunction after microembolization was comparable to occlusion/reperfusion. This MR study suggests that the pattern of myocardial damage plays a role in LV dysfunction.

The purpose of this study was to test the potential of clinical imaging modalities, 64-slice multidetector computed tomography (MDCT) and 1.5T magnetic resonance imaging (MRI) for qualitative and quantitative evaluation of acute microinfarcts and to determine the effects of

To provide evidence that vascular endothelial growth factor (VEGF) genes delivered transendocardially with magnetic resonance (MR) imaging guidance may neovascularize or improve vascular recruitment in occlusive infarction.All experimental procedures received approval from the institutional committee on animal research. Dogs with permanent coronary artery occlusion were imaged twice (3 days after occlusion for assessment of acute infarction; a mean of 50 days after occlusion +/- 3 [standard error of the mean] for assessment of chronic infarction). A mixture of plasmid VEGF and plasmid LacZ (n = 6, treated animals) or plasmid LacZ and sprodiamide (n = 6, placebo control animals) was delivered to four sites. MR fluoroscopy was used to target and monitor delivery of genes. The effectiveness of this delivery approach was determined by using MR imaging methods to assess perfusion, left ventricular (LV) function, myocardial viability, and infarct resorption. Histologic evaluation of neovascularization was then performed.MR fluoroscopic guidance of injectates was successful in both groups. Treated animals with chronic, but not those with acute, infarction showed the following differences compared with control animals: (a) steeper mean maximum upslope perfusion (200 sec(-1) +/- 32 vs 117 sec(-1) +/- 15, P = .02), (b) higher peak signal intensity (1667 arbitrary units +/- 100 vs 1132 arbitrary units +/- 80, P = .002), (c) increased ejection fraction (from 27.9% +/- 1.2 to 35.3% +/- 1.6, P = .001), (d) smaller infarction size (as a percentage of LV mass) at MR imaging (8.5% +/- 0.9 vs 11.3% +/- 0.9, P = .048) and triphenyltetrazolium chloride staining (9.4% +/- 1.5 vs 12.7% +/- 0.4, P = .05), and (e) higher vascular density (as number of vessels per square millimeter) at the border (430 +/- 117 vs 286 +/- 19, P = .0001) and core (307 +/- 112 vs 108 +/- 17, P = .0001).The validity of plasmid VEGF gene delivered with MR fluoroscopic guidance into occlusive infarction was confirmed by neovascularization associated with improved perfusion, LV function, and infarct resorption.

VM202, a newly constructed plasmid human hepatocyte growth factor, was transferred intramyocardially after infarction for the purpose of evaluating this strategy as a therapeutic approach for protection from left ventricular (LV) remodeling.The institutional animal care and use committee approved this study. Pigs underwent coronary artery occlusion and reperfusion and served as either control (n = 8) or VM202-treated (n = 8) animals. VM202 was transferred intramyocardially into four infarcted and four periinfarcted sites. Cardiac magnetic resonance (MR) imaging (cine, perfusion, delayed enhancement) was performed in acute (3 days) and chronic (50 days +/- 3 [standard error of the mean]) infarction. Histopathologic findings were used to characterize and quantify neovascularization. The t test was utilized to compare treated and control groups and to assess changes over time.In acute infarction, MR imaging estimates of function, perfusion, and viability showed no difference between the groups. In chronic infarction, however, VM202 increased maximum signal intensity and upslope at first-pass perfusion imaging and reduced infarct size at perfusion and delayed-enhancement imaging. These changes were associated with a decrease in end-diastolic (2.15 mL/kg +/- 0.12 to 1.73 mL/kg +/- 0.10, P.01) and end-systolic (1.33 mL/kg +/- 0.07 to 0.92 mL/kg +/- 0.08, P.001) volumes and an increase in ejection fraction (38.2% +/- 1.3 to 47.0% +/- 1.8, P.001). In contrast, LV function deteriorated further in control animals. Compared with control animals, VM202-treated animals revealed peninsulas and/or islands of viable myocardium in infarcted and periinfarcted regions and greater number of capillaries (218 per square millimeter +/- 19 vs 119 per square millimeter +/- 17, P.05) and arterioles (21 per square millimeter +/- 4 vs 3 per square millimeter +/- 1, P.001).Intramyocardial transfer of VM202 improved myocardial perfusion, viability, and LV function.

One approach to analgesia is to block pain at the site of origin or along the peripheral pathway by selectively ablating pain-transmitting neurons or nerve terminals directly. The heat/capsaicin receptor (TRPV1) expressed by nociceptive neurons is a compelling target for selective interventional analgesia because it leaves somatosensory and proprioceptive neurons intact. Resiniferatoxin (RTX), like capsaicin, is a TRPV1 agonist but has greater potency. We combine RTX-mediated inactivation with the precision of computed tomography (CT)–guided delivery to ablate peripheral pain fibers in swine. Under CT guidance, RTX was delivered unilaterally around the lumbar dorsal root ganglia (DRG), and vehicle only was administered to the contralateral side. During a 4-week observation period, animals demonstrated delayed or absent withdrawal responses to infrared laser heat stimuli delivered to sensory dermatomes corresponding to DRG receiving RTX treatment. Motor function was unimpaired as assessed by disability scoring and gait analysis. In treated DRG, TRPV1 mRNA expression was reduced, as were nociceptive neuronal perikarya in ganglia and their nerve terminals in the ipsilateral dorsal horn. CT guidance to precisely deliver RTX to sites of peripheral pain transmission in swine may be an approach that could be tailored to block an array of clinical pain conditions in patients.

Background and purpose The rabbit small clot embolic model for large vessel occlusion (LVO) is well established, yet has limitations. Blind introduction of autologous thrombus often fails to completely occlude a target vessel and, when successful, the precise timing of occlusion and revascularization is difficult to control. Studies of cellular biology and neuroimaging of acute reversible cerebral ischemia (ie, penumbral tissue) would benefit from a rabbit model in which LVO can be reliably induced, easily confirmed, and in which the time of occlusion and revascularization can be precisely controlled. Methods Transfemoral 1.5 F microcatheterization of the posterior cerebral artery (PCA) was performed in anesthetized rabbits (n=7) using fluoroscopic guidance. LVO with the wedged microcatheter was maintained for 30–210 min followed by reperfusion. Diffusion-weighted and T2 fluid-attenuated inversion recovery (FLAIR) MRI was performed 3 h after catheter removal on a 3 T scanner. Post-mortem histopathologic analysis of brain tissue was performed using triphenyltetrazolium chloride (TTC). Results Placing of the 1.5 F microcatheter tip in the PCA was successful in all seven animals. Infarct size on matched diffusion-weighted and TTC sections was strongly correlated (r 2 =0.86). Transient PCA occlusion of 30–60 min resulted in infarction of the ipsilateral hippocampus and thalamus, sparing the cortex, while more prolonged occlusion (180–210 min) resulted in cortical infarction as well. Conclusions Image-guided microcatheter induction of PCA occlusion in rabbits can consistently produce time-dependent infarction of cortical and subcortical structures that is reliably detected by diffusion-weighted MRI, and thus may be a useful model for therapeutic studies in acute ischemic stroke.

BACKGROUND AND PURPOSE: Endovascular navigation under MR imaging guidance can be facilitated by a catheter with steerable microcoils on the tip. Not only do microcoils create visible artifacts allowing catheter tracking, but also they create a small magnetic moment permitting remote-controlled catheter tip deflection. A side product of catheter tip electrical currents, however, is the heat that might damage blood vessels. We sought to determine the upper boundary of electrical currents safely usable at 1.5T in a coil-tipped microcatheter system. MATERIALS AND METHODS: Alumina tubes with solenoid copper coils were attached to neurovascular microcatheters with heat shrink-wrap. Catheters were tested in carotid arteries of 8 pigs. The catheters were advanced under x-ray fluoroscopy and MR imaging. Currents from 0 mA to 700 mA were applied to test heating and potential vascular damage. Postmortem histologic analysis was the primary endpoint. RESULTS: Several heat-mitigation strategies demonstrated negligible vascular damage compared with control arteries. Coil currents ≤300 mA resulted in no damage (0/58 samples) compared with 9 (25%) of 36 samples for > 300-mA activations (P = .0001). Tip coil activation ≤1 minute and a proximal carotid guide catheter saline drip > 2 mL/minute also had a nonsignificantly lower likelihood of vascular damage. For catheter tip coil activations ≤300 mA for ≤1 minute in normal carotid flow, 0 of 43 samples had tissue damage. CONCLUSIONS: Activations of copper coils at the tip of microcatheters at low currents in 1.5T MR scanners can be achieved without significant damage to blood vessel walls in a controlled experimental setting. Further optimization of catheter design and procedure protocols is necessary for safe remote control magnetic catheter guidance.

AimTo use magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU), magnetic resonance imaging (MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue.MethodsSix anesthetized/mechanically-ventilated pigs underwent single/double renal sonication (n = 24) using a 3T-MRg-HIFU (1.1 MHz frequency and 3000J-4400J energies). T2-weighted fast spin echo (T2-W), perfusion saturation recovery gradient echo and contrast enhanced (CE) T1-weighted (T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically significant.ResultsAblated renal parenchyma could not be differentiated from normal parenchyma on T2-W or non-CE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images in vivo (0.12-0.36 cm(3) for single sonication 3000J, 0.50-0.84 cm(3), for double 3000J, 0.75-0.78 cm(3) for single 4400J and 0.12-2.65 cm(3) for double 4400J) and at postmortem (0.23-0.52 cm(3), 0.25-0.82 cm(3), 0.45-0.68 cm(3) and 0.29-1.80 cm(3), respectively) were comparable. The ablated volumes on 3000J and 4400J double sonication were significantly larger than single (P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively.ConclusionContrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.

Background Volumes and sizes of dislodged coronary microemboli vary during PCI so their effects at the left ventricular (LV) and cellular levels cannot be quantified. Furthermore, biopsy for tissue characterization is not an option in PCI patients. Purpose To characterize and validate microinfarct size, LAD territory where microinfarct were found using multidetector computed tomography (MDCT), histochemical staining and microscopy as a function of microemboli volumes and to scale the effects of microemboli volumes on LV function. Material and Methods Under X-ray guidance, a 3F catheter was inserted into LAD coronary artery of 14 pigs for delivering 16 mm3 or 32 mm3 of 40-120 μm microemboli. MDCT imaging/histochemical staining/ microscopy were performed 3 days later and used to characterize regional and global structural and functional changes in LV by threshold/planimetric methods. Results MDCT and ex-vivo methods were able to quantify microinfarct size and LAD territory where microinfarct was found as a function of volumes. However, MDCT and histochemical staining significantly underestimated microinfarct size and territory where microinfarct was found compared with microscopy. MDCT demonstrated the functional changes and showed a moderate correlation between LV ejection fraction and microinfarct size (r = 0.53). Microscopy provided higher spatial resolution for measuring islands of necrotic cells, which explains the difference in measuring structural changes. Conclusion MDCT showed the difference in microinfarct size and LAD territory as a function of microemboli volumes and scaled the changes in LV function. This experimental study gives clinicians a reference for the effects of defined microemboli volumes on myocardial viability and LV function and the under-estimation of microinfarct on MDCT.

Coronary filtration devices showed inadequate protection during PCI due to the inability to filter microemboli120 μm in diameter. The purpose of this study was to determine the impact of two volumes of120 μm microemboli on LV function, perfusion and viability using magnetic resonance imaging (MRI).Under X-ray guidance, pigs (n = 18) received two different volumes (16 mm(3) or 32 mm(3)) of 40-120 μm microemboli (intracoronary). At 3 days, regional myocardial perfusion and LV function were assessed using first pass perfusion and cine MRI. Viability MRI was performed in beating and non-beating hearts to delineate microinfarcts and compare with histochemical triphenyltetrazolium chloride stain, using semi-automatic threshold method. Histology and cardiac injury enzymes were used to confirm the presence of microinfarcts and characterize cellular and vascular changes.Microinfarcts were visible as enhanced specks on DE-MRI in all animals that received 32 mm(3), but only two-third of the animals that received 16 mm(3), volume. The decline in ejection fraction and increase in LV volumes and microinfarcts were volume dependent. Regional perfusion and contractility were significantly reduced in the LAD territory compared with remote myocardium. Histology showed apoptosis, edema, inflammation and vascular thrombosis.Microemboli of120 μm have deleterious effects on LV function, perfusion and viability and the effects are dependent on microemboli volume. Microinfarct visualization is crucial to ensure that myocardial dysfunction is related to dislodged microemboli and not only to pre-procedural stunning or hibernation. This noninvasive MRI method may help in evaluating the effectiveness of coronary filtration devices in protecting myocardium from microemboli.

Rationale and Objectives To determine the potential of multidetector computed tomography (MDCT) in assessing, at 72 hours, the effects of distal coronary microembolization on myocardial structure and function. Materials and Methods Microembolic material (total volume=16 mm 3 of 40–120 μm diameter) was selectively delivered in the left anterior descending coronary artery under x-ray fluoroscopy ( n = 6 pigs). After 72 hours, 64-slice MDCT was used to assess LV function, perfusion, and viability. For comparison between the measurements at 80 kV, 120 kV, and postmortem we used Bland-Altman and Pearson correlation. Histochemical and histopathological staining was used for quantitative and qualitative characterization of microinfarct. Results Cine MDCT showed the deleterious effects of microembolization on systolic wall thickening, LV volumes, and ejection fraction. Perfusion parameters, such as max upslope, peak attenuation, and time to peak, differed between microinfarct territory and remote myocardium. Inconsistency in visualizing microinfarct was observed using tube voltages of 80 kV and 120 kV. The extent of heterogeneous microinfarct was 4.5 ± 1.0 % of LV mass at 80 kV, 6.1 ± 0.9% LV at 120 kV, and 5.9 ± 1.1% LV on postmortem. There was significant difference in the extent of microinfarct measured on 80 kV MDCT compared with 120 kV and postmortem. Microscopic examination revealed the random distribution of obstructed microvessels surrounded by myocardial necrosis and inflammatory cells in all animals. Conclusion Both visible and nonvisible microinfarct cause perfusion deficit and LV dysfunction. MDCT is sensitive for quantifying early functional changes in LV caused by microembolization. Further improvement in spatial resolution of this technology is needed to improve visualization of microinfarct.

In an open-chest model of acute infarct, epicardial delivery of hepatocyte growth factor (pCK-HGF-X7) gene improved left ventricle (LV) function. This study was designed to test (a) the efficacy of HGF gene in infarct scar delivered under magnetic resonance (MR) guidance and (b) the potential of multiple MR sequences in assessing the effects of pCK-HGF-X7 (treatment) and pCK-LacZ (control) genes on myocardial structure and function.Swine (six per group) were subjected to myocardial infarct, under X-ray fluoroscopy, and developed LV remodeling at 5 weeks. Multiple clinical magnetic resonance (MR) imaging sequences were performed before delivery of gene (at 5 weeks after infarction) and 5 weeks after delivery of gene. Under MR guidance, the active endovascular catheter was introduced into LV to transendocardially deliver 3.96 × 10(11) viral copies of pCK-HGF-X7 or pCK-LacZ in the border and core of the infarct scar. Histological evaluation of the infarct scar was performed 5 weeks after delivery of gene.At 5 weeks after infarction, there was no significant difference in measured cardiovascular MR parameters between the groups. The pCK-HGF-X7 gene caused significant improvement in the following parameters (P.05 for these parameters): three-dimensional (3D) strain (radial, circumferential, and longitudinal) and perfusion (maximum upslope, peak signal intensity, and time to peak) compared with control pCK-LacZ at 5 weeks after delivery of the genes. The ejection fraction was higher in pCK-HGF-X7-treated (43 ± 1%) than in pCK-LacZ control (37 ± 1%, P.05) animals. These changes are associated with a decrease in infarct scar size (11.3 ± 2.0% in pCK-LacZ control and 6.7 ± 1.3% in pCK-HGF-X7-treated animals, P.01) and infarct transmurality in four out of five infarct scar segments (P.05) on delayed contrast-enhanced MR imaging. Microscopic study confirmed the increase in capillary (P.05) and arteriole (P.05) density of infarct scar in pCK-HGF-X7-treated animals compared with pCK-LacZ control animals.Hepatocyte growth factor gene (pCK-HGF-X7) delivered under MR guidance into infarct scar ameliorated global function and 3D strain, increased regional perfusion and infarct resorption, and enhanced angiogenesis/arteriogenesis. This feasibility study provides novel approach and analysis methods and instrumentation for delivering and evaluating new locally delivered therapies.

Methods In this study the HGF gene was injected intramyocardially in reperfused infarction (2 hr occlusion), for the purpose of evaluating this strategy as a therapeutic approach for protection from LV remodeling. MR imaging was performed at 3 days and 7–8 weeks on a 1.5-T MR clinical scanner (Philips Medical Systems). First pass perfusion, delayed contrast enhancement and cine MR imaging was used in the evaluation. Triphenyltetrazolium chloride (TTC) and histopathological (Masson's trichrome and Biotinylated Bandeiria simplicifolia isolectin B4) stains were utilized to quantify vascular density and myocardial viability. Results The peak signal intensity (SI), extents of hypoenhanced ischemic myocardium and max upslope data in the two groups were not significantly different at 3 days. At 7–8 weeks peak signal intensity was higher and maximum upslope data was steeper in treated animals compared to controls. The extent of hyperenhanced scar was significantly larger in control (13.2 ± 1.6% LV) compared with HGF treated (7.0 ± 0.5% LV) animals. TTC analysis also showed that the extent of scar tissue was significantly larger in control (12.0 ± 1.7%) compared with treated (6.6 ± 0.7% LV, P = 0.04) animals. There was no significant difference between the extent of hyperenhanced scar on MRI and TTC (P = 0.32). The infarction tended to be non-transmural with a residual thicker wall in treated compared with control animals both on MR images and TTC. Control animals showed evidence of LV remodeling, which was reflected by increased end systolic volumes and decline in ejection fraction. Treated animals showed a decrease from in end diastolic (2.15 ± 0.12 to 1.82 ± 0.12, P = 0.008) and end systolic (1.33 ± 0.07 to 1.00 ± 0.08, P = 0.001) volumes. They also showed increased ejection fraction (40.3 ± 1.3 to 45.7 ± 1.8, P = 0.001).

The objectives of the study were: (1) to compare the kinetics of a new gadolinium-based low-diffusibility magnetic resonance (MR) contrast medium, P846 and Gd-DOTA in left ventricular (LV) blood and in normal and ischemically injured myocardium using inversion recovery echo-planar imaging (IR-EPI) and (2) to compare the enhancement pattern after injection of P846 with Gd-DOTA, using T1-weighted spin-echo imaging (T1-SE). Sixteen rats were subjected to left descending artery (LAD) occlusion for 30 min, followed by 2.5 h reperfusion. MR imaging was performed before and after administration of the contrast medium in two different groups of animals: one group (n = 8) received 0.05 mmol kg(-1) P846 and the other (n = 8) 0.1 mmol kg(-1) Gd-DOTA. A blipped IR-EPI and a multislice T1-SE were performed before injection and for 90 min after injection. T1-values were derived by fitting regional signal intensity on the IR-EPI images, the R1, DeltaR1 (R(1postcontrast) - R(1precontrast)) and DeltaR1 ratios were calculated in LV blood, normal and injured myocardium. On SE-T(1), the signal intensity ratio (SI) and extent of injury were measured. True infarct size was measured using histochemical staining. Changes in DeltaR(1) were 4.8 times greater with 0.05 mmol kg(-1) P846 than with 0.1 mmol kg(-1) Gd-DOTA in LV blood (6.3 +/- 0.9 vs 0.9 +/- 0.1 s(-1), p < 0.0001), normal (1.7 +/- 0.2 vs 0.34 +/- 0.03 s(-1), p < 0.0001) and ischemically injured myocardium (5.4 +/- 0.4 vs 1.6 +/- 0.1 s(-1), p < 0.0001). MR imaging experiments showed that the signal enhancement with P846 is longer (90 min), which might be explained by a lower diffusion of P846 compared with Gd-DOTA (30 min). P846 differentiates viable and nonviable myocardium. Despite lower gadolinium dose, P846 permits differentiation of viable and nonviable myocardium owing to a high contrast and a long imaging window with conventional t1-weighted SE sequence.

This study has two objectives: (1) to compare the kinetics of low diffusion P846 with Gd-DOTA using inversion recovery echo planar (IR-EPI) magnetic resonance (MR) imaging and (2) to determine the potential of P846 in defining myocardial viability in hearts subjected to various injuries using T1-weighted spin echo (T1-SE).Rats were subjected to (1) occlusive infarcts (n = 16), (2) reperfused ischemic injuries (n = 8) or (3) reperfused infarcts (n = 16). A dose of 0.05 mmol/kg P846 was compared to 0.1 mmol/kg Gd-DOTA. IR-EPI and T1-SE images were obtained during 60 min. T(1), DeltaR(1) and DeltaR(1) ratio were measured on IR-EPI. Infarct extents were evaluated on T1-SE and compared with histochemical staining.Blood DeltaR(1) was higher at 5 min after P846 (6.36 +/- 0.32 s(-1)) than after Gd-DOTA (1.30 +/- 0.14 s(-1); P0.001). With P846, occlusive infarcts appeared as a hypoenhanced region surrounded by a hyperenhanced rim that lasted for 60 min. The increase in the DeltaR(1) ratio value was slower after P846 than with Gd-DOTA in the reperfused infarcts, suggesting low diffusion/convection of P846. Gd-DOTA homogenously enhanced both occlusive and reperfused infarcts at 30 min.P846 provides better contrast and extended discrimination between occlusive and reperfused infarcts compared with Gd-DOTA. The gadolinium dose could be reduced with P846.

To prospectively investigate the long-term effect of adeno-associated viral (AAV) vector-encoding vascular endothelial growth factor gene (VEGF) (AAV-VEGF) on left ventricular (LV) mass and volumes, as well as on regional contractility and circumferential strain, in a swine model of reperfused myocardial infarction.All experimental procedures received approval from the institutional committee on animal research. Of 16 pigs subjected to reperfused myocardial infarction, six were treated, six were controls, and four died during the ischemic intervention. In six animals, cardiac-specific AAV-VEGF was injected into the periinfarcted and infarcted myocardium 1 hour after reperfusion. Magnetic resonance (MR) imaging was performed at 3 days and 8 weeks after infarction by using cine, tagged, and delayed enhancement (with gadoterate meglumine) sequences to measure global and regional LV function and infarct size. At postmortem examination, tissue samples stained with isolectin B4, Masson trichrome, and hematoxylin-eosin were used to characterize injured myocardium. Two-tailed Student t test was used for statistical analysis.Six treated animals showed no change in mean LV ejection fraction after 8 weeks (40.3%+/-0.9 [standard error of the mean] vs 41.0%+/-0.7) in contrast to a decrease measured in six control animals (41.4%+/-0.7 vs 36.1%+/-0.6, P.001). AAV-VEGF improved wall thickening and circumferential strain in periinfarcted and remote myocardium. A greater reduction in gadoterate meglumine-enhanced infarct area was measured in treated animals (18.6%+/-1.5 of the LV mass at 3 days vs 9.8%+/-1.0 of the LV mass at 8 weeks, P.001) compared with control animals (17.7%+/-2.0 vs 14.8%+/-1.0, P=.008). Findings at histopathologic evaluation indicated an increase in vascular density and a decrease in myocyte diameter in the periinfarcted myocardium of treated, compared with control, animals.Angiogenesis and arteriogenesis induced by VEGF genes improved regional myocardial strain and wall thickening and preserved ejection fraction after infarction.

To prospectively determine in swine the effects of cardiac-specific and hypoxia-inducible vascular endothelial growth factor (VEGF) expression gene on angiogenesis and arteriogenesis by using cardiovascular magnetic resonance (MR) imaging for evaluation of infarct resorption and left ventricular (LV) function.The investigation conformed to U.S. National Institutes of Health guidelines. Twelve pigs with reperfused infarcts were studied with cardiovascular MR 3 days and 8 weeks after surgery. In six pigs, adeno-associated viral (AAV) vector-encoding VEGF (AAV-VEGF) gene was injected at eight sites 1 hour after reperfusion. Six pigs served as controls. Cardiovascular MR measurements of perfusion, area at risk, infarct size, and LV function were used in evaluation of the therapy. Hematoxylin-eosin, Masson trichrome, and biotinylated isolectin B4 stains were used to assess regional vascular density. Two-way Student t test was used to determine significant differences between means.AAV-VEGF had no effect on cardiovascular MR perfusion or infarct size measurements 3 days after infarction. At 8 weeks, the therapy increased infarct resorption, perfusion, and vascular density and prevented deterioration of ejection fraction in treated animals. These changes were associated with a significantly greater reduction in extent of enhanced region in treated (18.6% of LV surface area +/- 1.5 [standard error of mean] to 9.8% +/- 1.1) than in control animals (17.7% +/- 1.8 to 14.5% +/- 1.5, P = .028). Histopathologic findings in treated animals showed increased capillary and arterial density in infarct and periinfarct regions. These new vessels were active and thin-walled compared with thick-walled vessels of control animals.AAV-VEGF improves cardiovascular MR measurement of regional myocardial perfusion and LV function.

Purpose Using real-time MRI for solid organ embolization provides physiologic and structural information. Current embolization under x-ray guidance only visualizes the vessels and lacks a quantifiable endpoint, which could be overcome by using MRI. The purpose of this study was to use a magnetically assisted remote controlled (MARC) catheter under real-time endovascular MRI to navigate into the renal arteries, embolize with gadolinium (Gd) impregnated microspheres, and measure the reduction in flow. Method and materials The catheter device was constructed using 4.1Fr custom copper braided catheter (Penumbra Inc., Alameda, CA) with copper wires in the wall connected to a laser-lithographed saddle coil at the distal tip (Figure 1). The copper wires were connected to an in-room MRI compatible cart via an SFTP cable. A foot pedal actuator was used to deliver ± 450mA to deflect the catheter. In vivo navigation was tested in four farm pigs (40–45 kg). The renal arteries were catheterized under a real-time b-SSFP sequence at 1.5T. Embolization was visualized under a real-time contrast enhanced angiographic sequence. Renal artery blood flow rates were assessed with ECG gated velocity-encoded MR imaging before and after embolization with Gd-impregnated microspheres (100–300 μm). Workflow is diagrammed in Figure 2. Statistical analysis was performed and data were presented as mean ± SD. Results The catheter tip was clearly visible under MRI guidance. Three (75%) out of four renal arteries were successfully catheterized. Overall mean catheterization time was (956 s). The MR signal from the Gd-impregnated spheres was observed under real-time MRI (Figure 3). Flow rate was significantly different (P = 0.025) between pre and post embolization (2.20 ± 0.20 vs. 0.14 ± 0.03 mL/min/kg), accounting for a 94 percent reduction in flow. Conclusion Using a MARC catheter for renal artery catheterization and embolization under real-time MRI is feasible. The MARC catheter system provides a novel opportunity to perform endovascular procedures in interventional MRI environment. Future work will focus on developing more flexible catheters that can be used for head, neck, and brain embolization applications. Disclosures S. Hetts: 1; C; NIH-NIBIB, NIH-NCI, Penumbra, Siemens, Stryker, MicroVention Terumo. 2; C; Stryker, Penumbra, Silk Road Medical, Medina Medical. 4; C; Medina Medical. 5; C; UCSF. A. Losey: None. P. Lillaney: None. D. Cooke: None. B. Thorne: None. J. Yang: None. L. Sze: None. L. Do: None. A. Martin: None. M. Saeed: None. M. Wilson: None.

ObjectivesThe purpose of this study was to examine the potential of intravascular gadolinium (Gd)-chelates in discriminating acute from chronic myocardial infarctions (MIs).BackgroundA potential limitation of delayed contrast enhanced magnetic resonance imaging with standard extracellular Gd-chelates is its inability to distinguish acute from chronic MIs.MethodsEight pigs with MIs were studied at 3 days and 8 weeks. Inversion recovery gradient echo (IR-GRE), T1-turbo spin echo (TSE), and T2-TSE images were acquired before and after administration of intravascular and extracellular Gd-chelates. Triphenyltetrazolium chloride (TTC) was used to delineate infarctions at postmortem. Masson’s trichrome and Biotinylated Bandeiria simplicifolia Isolectin B4 stains were used to characterize scarred myocardium. Analysis of variance was used to compare signal intensity (SI) ratios and determine differences in infarct extent.ResultsThe intravascular agent produced differential enhancement of acute infarctions at 3 days (SI ratio 5.8 ± 1.3) but not at 8 weeks (1.6 ± 0.4, p < 0.01). The extracellular agent provided differential enhancement of both acute (SI ratio 7.7 ± 1.4) and chronic (7.5 ± 0.9) infarctions. The extents of enhanced regions in acute infarctions were not different after intravascular (16.0 ± 1.3%) or extracellular (17.1 ± 1.7%) agents; at 8 weeks the extent of extracellular enhanced and TTC regions were smaller (13.2 ± 1.4% and 12.0 ± 1.5%, respectively). Masson’s trichrome stain demonstrated dense scar tissue, signaling the complete healing of infarction. The vascular stain showed that scar tissue contained fewer microvessels oriented in a haphazard array.ConclusionsThe combination of intravascular and extracellular Gd-chelates discriminates acute from chronic infarctions on delayed images. This double contrast agent approach can be used to determine the age and extent of infarctions.

Purpose Interventional MRI offers the ability to provide soft tissue contrast and functional information in the absence of ionizing radiation. However, performing endovascular procedures in MRI raises safety concerns due to heating from the metallic braid incorporated into catheters. Heating in tungsten and nitinol braided catheters was assessed in an in vitro model simulating a patient undergoing a scan at specific absorption rate (SAR) level of 4 W/kg. Materials and Methods Heating adjacent to the catheters was assessed with fluoroptic temperature probes placed at the device tip, 5cm, 10cm, and 20cm proximal to the tip in a polyacrylamide gel in the head portion of a phantom. A 2.8F tungsten braided catheter (Terumo Progreat, Somerset, NJ) and a 1.9F nitinol braided catheter (eV3 Echelon, Irvine, CA) were serially embedded in a laterally offset conformation. A 5F stainless steel braided catheter (Cook Beacon Tip Torcon Advantage, Bloomington, IN) was used as a positive control and a temperature sensor was placed in background gel, well away from devices. Endovascular devices were immersed at 98cm and exposed to 2-min of scanning followed by 8-min without scanning. The immersed length was shortened by 5cm and this cycle was repeated until the immersed length was 63cm. MR scanning was based on modified fast spin echo imaging on a 1.5T scanner. Results The tungsten braided catheter did not show heating. The maximal heating for the nitinol braided catheter occurred at 20cm proximal to the tip at an immersed length of 93cm. The maximal initial rate of heating was 4.00°C/min and the maximal temperature rise during a 2-min scan was 2.32°C. Heating varied along the catheter, with the most heating at 10cm and 20cm proximal to the tip. The maximal temperature rise during a 2-min scan was 0.33°C for the background and 2.65°C for the positive control. Conclusion The study provides information on the magnitude of focal heating induced in a head simulating a “worst-case” scenario of a patient undergoing a neurovascular procedure. Nitinol displayed substantial heating when compared to the tungsten device. This tungsten braided catheter showed potential safe use in interventional MRI without substantial SAR restrictions.

Chronic treatment with glucocorticoids (GCs) leads to significant bone loss and increased risk of fractures. In chronically GC-treated patients, hip fracture risk is nearly 50%. The purpose of this investigation was to determine if there are differences in the quantities of trabecular and cortical bone and bone strength of the hip between GC-treated osteoporotic patients and controls. Methods: Study subjects were GC-treated osteoporotic postmenopausal women, and controls were postmenopausal women, recruited for separate clinical trials. Quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA) of the hip were obtained from all subjects. QCT outcome variables measured included total, cortical, and trabecular BMD of hip subregions (femoral neck and trochanter) and total hip. In addition, finite element modeling (FEM) was performed on a subset of 19 cases and 38 controls, matched on age (± 5 years), weight (± 5 kg), and history of hormone replacement (>1 year use) to assess failure load in stance and fall loading conditions. Generalized linear models were used to adjust the QCT variables for covariates between groups. Multiple regression was performed to identify independent predictors of bone strength from the QCT variables. Results: Compared with controls, GC-treated subjects were significantly (p

Purpose Interventional MRI offers the unique capability to steer catheters by creating a magnetic field near the catheter tip. Efficacy of MR guided navigation must be tested in vitro in vascular phantoms that mimic the in vivo environment. Previous vascular phantoms have shortcomings including lack of MRI compatibility, artifact creation, non-physiologic stiffness, and high frictional resistance that limits navigation capabilities. We sought to develop a vascular phantom from poly(vinyl) alcohol cryogel (PVA-C) that overcomes these limitations and provides a tool to test our magnetically-assisted remote control (MARC) endovascular catheter. Materials and Methods Design considerations for the phantom were as follows: MRI compatible, MR relaxation times similar to body tissues, smooth lumen that mimics vessel feel during navigation, compatible with flow, range of navigational difficulty, and the ability to accommodate 6 French catheters. Phantom Box Construction: To provide physiologically relevant vessel trajectories, multiple symmetric angles (30-90°) and diameters (3/16-7/8 in.) were designed from Delrin rods connected together and placed in an acrylic box. PVA-C was poured into the phantom box and cross-linked with freeze-thaw cycles. The rods were removed leaving pathways mimicking vessel lumens. PVA-C Process: A gel was created using a process previously outlined by Surry, et al. Sevol Grade 165 PVA powder (Sekisui Specialty Chemicals America, Dallas, TX) was used to create 500 ml 10% PVA-C. Four freeze-thaw cycle were performed on the gel. Images were obtained with a 1.5 T scanner using T1 and T2-weighted images, along with quantitative T1 and T2 measurements. Results T1 and T2 relaxation times (mean ± SD) for the PVA-C were 1195 ± 36 ms and 189 ± 5 ms. Radiographic T1 and T2 images of the test phantom will be shown. Conclusion The standard deviations show acceptable ranges for homogeneity, and the T1 and T2 values are in an acceptable range for tissue. These initial steps provide the foundation for a human-scale vascular phantom that can be used for testing navigation in our MARC endovascular catheter.