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1.  Quantitative and Semi-quantitative Measures of Regional Pulmonary Parenchymal Perfusion by Magnetic Resonance Imaging and their Relationships to Global Lung Perfusion and Lung Diffusing Capacity – The MESA COPD Study 
Investigative radiology  2013;48(4):223-230.
Objectives
To evaluate quantitative and semi-quantitative measures of regional pulmonary parenchymal perfusion in patients with COPD in relationship to global lung perfusion (GLP) and lung diffusing capacity (DLCO).
Materials and Methods
One hundred and forty three participants in the MESA COPD Study were examined by dynamic contrast-enhanced pulmonary perfusion MRI at 1.5 T. Pulmonary blood flow (PBF) was calculated on a pixel-by-pixel basis by using a dual-bolus technique and the Fermi function model. Semi-quantitative parameters for regional lung perfusion were calculated from signal-intensity time curves in the lung parenchyma. Intra- and inter-observer coefficients of variation (CV) and correlations between quantitative and semi-quantitative MRI parameters and with GLP and DLCO were determined.
Results
Quantitative and semi-quantitative parameters of pulmonary parenchymal perfusion were reproducible with CVs for all <10%. Furthermore, these MRI parameters were correlated with GLP and DLCO and there was good agreement between PBF and GLP. Quantitative and semi-quantitative MRI parameters were closely correlated (e.g., r=0.86 for maximum signal increase with PBF). In participants without COPD, the physiological distribution of pulmonary perfusion could be determined by regional MRI measurements.
Conclusion
Regional pulmonary parenchymal perfusion can reliably be quantified from dynamic contrast-enhanced MRI. MRI-derived quantitative and semi-quantitative perfusion measures correlate with GLP and DLCO.
doi:10.1097/RLI.0b013e318281057d
PMCID: PMC3952075  PMID: 23385398
Pulmonary perfusion; chronic obstructive pulmonary disease (COPD); dynamic contrast-enhanced MRI; quantitative perfusion maps; diffusing lung capacity
2.  Cardiac MRI evaluation of hypertrophic cardiomyopathy: Left ventricular outflow tract/aortic valve diameter ratio predicts severity of LVOT obstruction 
PURPOSE
To evaluate if left ventricular outflow tract /aortic valve (LVOT/AO) diameter ratio measured by cardiac magnetic resonance (CMR) imaging is an accurate marker for LVOT obstruction in patients with hypertrophic cardiomyopathy (HCM) compared to Doppler echocardiography.
MATERIALS AND METHODS
92 patients with hypertrophic cardiomyopathy were divided into 3 groups based on their resting echocardiographic LVOT pressure gradient (PG): <30mmHg at rest (non-obstructive, n=31), <30 mmHg at rest, >30mmHg after provocation (latent, n=29) and >30mmHg at rest (obstructive, n=32).The end-systolic dimension of the LVOT on 3-chamber steady state free precession (SSFP) CMR was divided by the end diastolic aortic valve diameter to calculate the LVOT/AO diameter ratio.
RESULTS
There were significant differences in the LVOT/AO diameter ratio among the 3 subgroups (non-obstructive 0.60±0.13, latent 0.41±0.16, obstructive 0.24±0.09, p<0.001). There was a strong linear inverse correlation between the LVOT/AO diameter ratio and the log of the LVOT pressure gradient (r=−0.84, p<0.001). For detection of a resting gradient >30mmHg, the LVOT/AO diameter ratio the area under the ROC curve was 0.91 (95% CI 0.85-0.97). For detection of a resting and/or provoked gradient >30mmHg, the LVOT/AO diameter ratio area under the ROC curve was 0.90 (95% CI 0.84-0.96).
CONCLUSION
The LVOT/AO diameter ratio is an accurate, reproducible, noninvasive and easy to use CMR marker to assess LVOT pressure gradients in patients with HCM.
doi:10.1002/jmri.23677
PMCID: PMC3411926  PMID: 22549972
hypertrophic cardiomyopathy; left ventricular outflow tract; MRI
3.  Pulmonary Function is Associated with Distal Aortic Calcium, not Proximal Aortic Distensibility. MESA Lung Study 
COPD  2011;8(2):71-78.
Forced expiratory volume in one second strongly predicts mortality from cardiovascular disease. FEV1 has been associated with aortic stiffness a strong independent predictor of cardiovascular mortality. However, the anatomical site and possible mechanisms linking aortic stiffness and lung function are unknown. We therefore examined if FEV1 and CT percent emphysema were associated with calcification of the abdominal aorta or reduced distensibility of the proximal thoracic aorta.
The Multi-Ethnic Study of Atherosclerosis (MESA) measured aortic calcification on cardiac and abdominal CT scans and proximal aortic distensibility using magnetic resonance among participants aged 45–84 years without clinical cardiovascular disease. Spirometry was measured following ATS/ERS guidelines and percent emphysema was measured in the lung fields of cardiac CT scans. Multivariate analyses adjusted for age, sex, race/ethnicity and cardiovascular risk factors.
Of 1,917 participants with aortic distensibility measures, 13% were current and 38% were former smokers. Eighteen percent had airflow limitation without asthma. FEV1 was associated with the extent of distal aortic calcification (0.76; 95%CI 0.60–0.97, p=0.02) but not proximal aortic calcification or proximal aortic distensibility (−0.04 mmHg−1; 95%CI −0.16–0.09 mmHg−1, p=0.60). Percent emphysema was associated with neither measure.
FEV1 was associated with severity of distal aortic calcification where it was present independently of smoking and other cardiovascular risk factors but not with distensibility or calcification of the proximal aorta.
doi:10.3109/15412555.2011.558543
PMCID: PMC3629728  PMID: 21495835
forced expiratory volume; pulmonary emphysema; aorta; calcification; compliance
4.  Semiquantified Noncalcified Coronary Plaque in Systemic Lupus Erythematosus 
The Journal of rheumatology  2012;39(12):2286-2293.
Objective
A major cause of morbidity and mortality in systemic lupus erythematosus (SLE) is accelerated coronary atherosclerosis. New technology (computed tomographic angiography) can measure noncalcified coronary plaque (NCP), which is more prone to rupture. We report on a study of semiquantified NCP in SLE.
Methods
Patients with SLE (n = 147) with no history of cardiovascular disease underwent 64-slice coronary multidetector computed tomography (MDCT). The MDCT scans were evaluated quantitatively by a radiologist, using dedicated software.
Results
The group of 147 patients with SLE was 86% female, 70% white, 29% African American, and 3% other ethnicity. The mean age was 51 years. In our univariate analysis, the major traditional cardiovascular risk factors associated with noncalcified plaque were age (p = 0.007), obesity (p = 0.03; measured as body mass index), homocysteine (p = 0.05), and hypertension (p = 0.04). Anticardiolipin (p = 0.026; but not lupus anticoagulant) and anti-dsDNA (p = 0.03) were associated with higher noncalcified plaque. Prednisone and hydroxychloroquine therapy had no effect, but methotrexate (MTX) use was associated with higher noncalcified plaque (p = 0.0001). In the best multivariate model, age, current MTX use, and history of anti-dsDNA remained significant.
Conclusion
Our results suggest that serologic SLE (anti-dsDNA) and traditional cardiovascular risk factors contribute to semiquantified noncalcified plaque in SLE. The association with MTX is not understood, but should be replicated in larger studies and in multiple centers.
doi:10.3899/jrheum.120197
PMCID: PMC3605898  PMID: 23027889
SYSTEMIC LUPUS ERYTHEMATOSUS; CARDIOVASCULAR DISEASE; RISK FACTORS; COMORBIDITY
5.  Glycemic Associations With Endothelial Function and Biomarkers Among 5 Ethnic Groups: The Multi‐Ethnic Study of Atherosclerosis and the Mediators of Atherosclerosis in South Asians Living in America Studies 
Background
The association of prediabetic states with endothelial dysfunction measured by flow‐mediated dilation (FMD) or endothelial biomarker levels remains controversial. We examined data from 5 ethnic groups to determine the association between glucose categories and FMD or endothelial biomarkers. We determined whether these associations vary by ethnic group or body mass index.
Methods and Results
We used data from 3516 participants from 5 race/ethnic groups with brachial FMD, endothelial biomarkers, and glucose category (normal, impaired fasting glucose [IFG], and diabetes) measures. There were significant ethnic differences in FMD, biomarker levels, and the prevalence of IFG and diabetes. However, all 5 ethnic groups showed similar patterns of higher FMD for the IFG group compared with the normal glucose and diabetes groups, which was most significant among whites and Asian Indians. Associations between glucose categories and endothelial biomarkers were more uniform, with the IFG and diabetes groups having higher biomarker levels than the normal glucose group. These associations did not change with further adjustment for fasting insulin levels. Whites with normal BMI had higher FMD values with higher glucose levels, but those with BMI in the overweight or obese categories had the inverse association (P for interaction=0.01).
Conclusions
The discordance of IFG being associated with higher FMD but more abnormal endothelial biomarker levels is a novel finding. This higher FMD for the IFG group was most notable in whites of normal BMI. The higher FMD among those with impaired fasting glucose may reflect differences in insulin signaling pathways between the endothelium and skeletal muscle.
doi:10.1161/JAHA.112.004283
PMCID: PMC3603246  PMID: 23525433
biomarkers; diabetes; endothelium; ethnicity; insulin resistance
7.  Increased Right Ventricular Septomarginal Trabeculation Mass is a Novel Marker for Pulmonary Hypertension: Comparison with Ventricular Mass Index and Right Ventricular Mass 
Investigative Radiology  2011;46(9):567-575.
Objective
To prospectively evaluate the cardiac magnetic resonance (MR) imaging-derived measurement of right ventricular (RV) septomarginal trabeculation (SMT) mass as a noninvasive marker for pulmonary hypertension (PH), compared to the ventricular mass index (VMI= RV mass/left ventricular mass) and RV mass.
Materials and Methods
Forty-nine patients (60 years ±12; 35 female) with suspected PH underwent cardiac MR and right heart catheterization (RHC) on the same day. Eighteen normal volunteers were also included. The performance of SMT mass, VMI and RV mass measurement, with regard to PH detection, was analyzed using receiver operating characteristic (ROC) curves. Logistic regression analysis was used to assess the association between SMT mass, RV mass, VMI, and PH.
Results
The area under the ROC curve for SMT mass/BSA, VMI and RV mass/BSA in diagnosing the presence or absence of PH was 0.88, 0.87 and 0.73 respectively. In multivariable models, both SMT mass/body surface area (BSA) (p=0.005, odds ratio 8.6) and VMI (p=0. 012, odds ratio 1.1) were found to be significant, independent predictors of PH.
Conclusion
Compared to RHC measurement, SMT mass and VMI are reproducible and non-invasive MR imaging markers for the diagnosis of PH.
doi:10.1097/RLI.0b013e31821b7041
PMCID: PMC3330237  PMID: 21577127
cardiac MRI; pulmonary hypertension; ventricular mass index; right ventricular septomarginal trabeculation
8.  In Hypertrophic Cardiomyopathy Reduction of Relative Resting Myocardial Blood Flow Is Related to Late Enhancement, T2-Signal and LV Wall Thickness 
PLoS ONE  2012;7(7):e41974.
Objectives
To quantify resting myocardial blood flow (MBF) in the left ventricular (LV) wall of HCM patients and to determine the relationship to important parameters of disease: LV wall thickness, late gadolinium enhancement (LGE), T2-signal abnormalities (dark and bright signal), LV outflow tract obstruction and age.
Materials and Methods
Seventy patients with proven HCM underwent cardiac MRI. Absolute and relative resting MBF were calculated from cardiac perfusion MRI by using the Fermi function model. The relationship between relative MBF and LV wall thickness, T2-signal abnormalities (T2 dark and T2 bright signal), LGE, age and LV outflow gradient as determined by echocardiography was determined using simple and multiple linear regression analysis. Categories of reduced and elevated perfusion in relation to non- or mildly affected reference segments were defined, and T2-signal characteristics and extent as well as pattern of LGE were examined. Statistical testing included linear and logistic regression analysis, unpaired t-test, odds ratios, and Fisher’s exact test.
Results
804 segments in 70 patients were included in the analysis. In a simple linear regression model LV wall thickness (p<0.001), extent of LGE (p<0.001), presence of edema, defined as focal T2 bright signal (p<0.001), T2 dark signal (p<0.001) and age (p = 0.032) correlated inversely with relative resting MBF. The LV outflow gradient did not show any effect on resting perfusion (p = 0.901). Multiple linear regression analysis revealed that LGE (p<0.001), edema (p = 0.026) and T2 dark signal (p = 0.019) were independent predictors of relative resting MBF. Segments with reduced resting perfusion demonstrated different LGE patterns compared to segments with elevated resting perfusion.
Conclusion
In HCM resting MBF is significantly reduced depending on LV wall thickness, extent of LGE, focal T2 signal abnormalities and age. Furthermore, different patterns of perfusion in HCM patients have been defined, which may represent different stages of disease.
doi:10.1371/journal.pone.0041974
PMCID: PMC3408401  PMID: 22860042
10.  Myocardial Delayed Enhancement in Pulmonary Hypertension: Pulmonary Hemodynamics, Right Ventricular Function, and Remodeling 
OBJECTIVE
The purpose of this study was to assess predictors of MRI-identified septal delayed enhancement mass at the right ventricular (RV) insertion sites in relation to RV remodeling, altered regional mechanics, and pulmonary hemodynamics in patients with suspected pulmonary hypertension (PH).
SUBJECTS AND METHODS
Thirty-eight patients with suspected PH were evaluated with right heart catheterization and cardiac MRI. Ten age- and sex-matched healthy volunteers acted as controls for MRI comparison. Septal delayed enhancement mass was quantified at the RV insertions. Systolic septal eccentricity index, global RV function, and remodeling indexes were quantified with cine images. Peak systolic circumferential and longitudinal strain at the sites corresponding to delayed enhancement were measured with conventional tagging and fast strain-encoded MRI acquisition, respectively.
RESULTS
PH was diagnosed in 32 patients. Delayed enhancement was found in 31 of 32 patients with PH and in one of six patients in whom PH was suspected but proved absent (p = 0.001). No delayed enhancement was found in controls. Delayed enhancement mass correlated with pulmonary hemodynamics, reduced RV function, increased RV remodeling indexes, and reduced eccentricity index. Multiple linear regression analysis showed RV mass index was an independent predictor of total delayed enhancement mass (p = 0.017). Regional analysis showed delayed enhancement mass was associated with reduced longitudinal strain at the basal anterior septal insertion (r = 0.6, p < 0.01). Regression analysis showed that basal longitudinal strain remained an independent predictor of delayed enhancement mass at the basal anterior septal insertion (p = 0.02).
CONCLUSION
In PH, total delayed enhancement burden at the RV septal insertions is predicted by RV remodeling in response to increased afterload. Local fibrosis mass at the anterior septal insertion is associated with reduced regional longitudinal contractility at the base.
doi:10.2214/AJR.09.4114
PMCID: PMC3034131  PMID: 21178051
delayed enhancement; fast strain-encoded imaging; MRI; pulmonary hypertension; tagging
11.  Bisphosphonate use and the Prevalence of Valvular and Vascular Calcification in Women: The Multi-Ethnic Study of Atherosclerosis 
Objectives
To determine whether nitrogen-containing bisphosphonate (NCBP) therapy is associated with the prevalence of cardiovascular calcification.
Background
Cardiovascular calcification correlates with atherosclerotic disease burden. Experimental data suggest that NCBP may limit cardiovascular calcification, which has implications for disease prevention.
Methods
The relationship of NCBP use to the prevalence of aortic valve, aortic valve ring, mitral annulus, thoracic aorta, and coronary artery calcification (AVC, AVRC, MAC, TAC, and CAC, respectively) detected by computed tomography was assessed in 3,636 women within the Multi-Ethnic Study of Atherosclerosis (MESA) using regression modeling.
Results
Analyses were age-stratified because of a significant interaction between age and NCBP use (interaction p-values: AVC p<0.0001; AVRC p<0.0001; MAC p=0.002; TAC p<0.0001; CAC p=0.046). After adjusting for age, body mass index, demographics, diabetes, smoking, blood pressure, cholesterol levels, and statin, hormone replacement, and renin-angiotensin inhibitor therapy, NCBP use was associated with a lower prevalence of cardiovascular calcification in women ≥65 years old (prevalence ratio [95% confidence interval]: AVC 0.68 [0.41, 1.13]; AVRC 0.65 [0.51, 0.84]; MAC 0.54 [0.33, 0.93]; TAC 0.69 [0.54, 0.88]; CAC 0.89 [0.78, 1.02]), whereas calcification was more prevalent in NCBP users among the 2,181 women <65 years old (AVC 4.00 [2.33, 6.89]; AVRC 1.92 [1.42, 2.61]; MAC 2.35 [1.12, 4.84]; TAC 2.17 [1.49, 3.15]; CAC 1.23 [0.97, 1.57]).
Conclusions
Among women in the diverse MESA cohort, NCBPs were associated with decreased prevalence of cardiovascular calcification in older subjects, but more prevalent cardiovascular calcification in younger ones. Further study is warranted to clarify these age-dependent NCBP effects.
doi:10.1016/j.jacc.2010.05.050
PMCID: PMC3004769  PMID: 21070928
bisphosphonate; calcification; coronary artery; valve; vascular
12.  Fibrinogen and Left Ventricular Myocardial Systolic Function: The Multi-Ethnic Study of Atherosclerosis 
American heart journal  2010;160(3):479-486.
Background
Increasing evidence suggests that elevated plasma fibrinogen is associated with incident heart failure. However, the underlying pathophysiological mechanisms have not been well elucidated.
Methods
We examined the relationship between plasma fibrinogen level and peak systolic mid-wall circumferential strain(Ecc) at the base, mid-cavity and apex of the left ventricle measured by magnetic resonance imaging myocardial tagging in 1,096 participants without clinical cardiovascular disease enrolled in the Multi-Ethnic Study of Atherosclerosis(MESA).
Results
After adjustment for demographics, established risk factors and body-mass-index, elevated fibrinogen was independently associated with reductions in absolute Ecc indicative of impaired systolic function in all regions(all P=0.015). The relationships were consistently significant upon further adjustment for measures of atherosclerosis(all P≤0.024), and were modestly attenuated with regional heterogeneity after additional adjustment for other inflammatory biomarker and N-terminal pro-brain-natriuretic peptide. In this fully-adjusted model, every one-standard deviation(74mg/dL) increment in plasma fibrinogen was independently associated with a reduction in left ventricular absolute Ecc of 0.29%(95%CI=0.03%–0.59%, P=0.048) at the base, 0.22%(95%CI=0.006%–0.43%, P=0.044) at mid-cavity, 0.20%(95%CI=−0.035%–0.43%, P=0.097) at the apex, and 0.24%(95%CI=0.05–0.43, P=0.015) overall.
Conclusions
Among asymptomatic individuals without clinical cardiovascular disease, elevated fibrinogen is independently associated with impaired myocardial systolic function. These findings support roles of inflammation, procoagulation and hyperviscosity underlying hyperfibrinogenemia in the pathogenesis of incipient myocardial dysfunction.
doi:10.1016/j.ahj.2010.06.001
PMCID: PMC2937158  PMID: 20826256
epidemiology; heart failure; myocardial function; fibrinogen; hyperviscosity; hypercoagulability; magnetic resonance imaging
13.  Left Ventricular Structure and Function by Cardiac Magnetic Resonance Imaging in Rheumatoid Arthritis 
Arthritis and rheumatism  2010;62(4):940-951.
Background
Heart failure is a major contributor to cardiovascular morbidity and mortality in rheumatoid arthritis. However, little is known about myocardial structure and function in this population.
Methods
Using cardiac magnetic resonance imaging, measures of myocardial structure and function were assessed in men and women with rheumatoid arthritis enrolled in ESCAPE RA, a cohort study of subclinical cardiovascular disease in rheumatoid arthritis, and compared with controls without rheumatoid arthritis enrolled in the Baltimore cohort of the Multi-Ethnic Study of Atherosclerosis.
Results
Myocardial measures were compared between 75 rheumatoid arthritis patients and 225 matched controls. After adjustment, mean left-ventricular mass was 26 grams lower for the RA group compared to controls (p<0.001), an 18% difference. After similar adjustment, mean left-ventricular ejection fraction, cardiac output, and stroke volume were modestly lower in the rheumatoid arthritis group vs. controls. Mean left-ventricular end-systolic and end-diastolic volumes did not differ by rheumatoid arthritis status. Within the rheumatoid arthritis group, higher levels of anti-CCP antibodies and current use of biologics, but not other disease activity or severity measures, were associated with significantly lower adjusted mean left-ventricular mass, end-diastolic volume, and stroke volume, but not ejection fraction. The combined associations of anti-CCP antibody level and biologic use on myocardial measures were additive, without evidence of interaction.
Conclusions
These findings suggest that the progression to heart failure in RA may occur through reduced myocardial mass rather than hypertrophy. Both modifiable and non-modifiable factors may contribute to lower levels of left-ventricular mass and volume.
doi:10.1002/art.27349
PMCID: PMC3008503  PMID: 20131277
myocardial dysfunction; heart failure; inflammation; cardiac imaging
14.  Comprehensive Adenosine Stress Perfusion MRI Defines the Etiology of Chest Pain in the Emergency Room: Comparison With Nuclear Stress Test 
Purpose
To compare standard of care nuclear SPECT imaging with cardiac magnetic resonance imaging (MRI) for emergency room (ER) patients with chest pain and intermediate probability for coronary artery disease.
Materials and Methods
Thirty-one patients with chest pain, negative electrocardiogram (ECG), and negative cardiac enzymes who underwent cardiac single photon emission tomography (SPECT) within 24 h of ER admission were enrolled. Patients underwent a comprehensive cardiac MRI exam including gated cine imaging, adenosine stress and rest perfusion imaging and delayed enhancement imaging. Patients were followed for 14 ± 4.7 months.
Results
Of 27 patients, 8 (30%) showed subendocardial hypoperfusion on MRI that was not detected on SPECT. These patients had a higher rate of diabetes (P = 0.01) and hypertension (P = 0.01) and a lower global myocardial perfusion reserve (P = 0.01) compared with patients with a normal cardiac MRI (n = 10). Patients with subendocardial hypoperfusion had more risk factors for cardiovascular disease (mean 4.4) compared with patients with a normal MRI (mean 2.5; P = 0.005). During the follow-up period, patients with subendocardial hypoperfusion on stress MRI were more likely to return to the ER with chest pain compared with patients who had a normal cardiac MRI (P = 0.02). Four patients did not finish the MR exam due to claustrophobia.
Conclusion
In patients with chest pain, diabetes and hypertension, cardiac stress perfusion MRI identified diffuse subendocardial hypoperfusion defects in the ER setting not seen on cardiac SPECT, which is suspected to reflect microvascular disease.
doi:10.1002/jmri.21899
PMCID: PMC3037112  PMID: 19787721
adenosine stress perfusion cardiac MRI; emergency room; chest pain; microvascular disease
15.  Extracoronary Abnormalities on Coronary Magnetic Resonance Angiography in the Multiethnic Study of Atherosclerosis Study: Frequency and Clinical Significance 
Objective
We examined the frequency and significance of extracoronary findings in a sample of asymptomatic of Multiethnic Study of Atherosclerosis participants who had coronary magnetic resonance angiography (MRA).
Subjects and Methods
The Multiethnic Study of Atherosclerosis is a cohort study that, at baseline, included 6814 participants 45 to 84 years old, and free of clinical cardiovascular disease. A random subset of 254 participants underwent coronary MRA. Two experienced readers evaluated all images, and a consensus reading was performed. The findings were classified based on their clinical significance.
Results
Extracoronary findings were detected in 101 (39.8%) of the 254 participants. Additional imaging or clinical referral was need for 15 (5.9%) of the 254 participants. None of the participants required emergency referral. Signal loss in a pulmonary artery branch due to navigator beam saturation occurred in 59 (23%) of the 254 participants simulating a pulmonary embolus.
Conclusions
The prevalence of reportable extracoronary findings on coronary MRA is high. Familiarity with noncardiac magnetic resonance imaging interpretation may help in avoiding unnecessary testing resulting from inconclusive identification of extracoronary abnormalities detected incidentally on coronary MRA.
doi:10.1097/RCT.0b013e318196bf2e
PMCID: PMC3034221  PMID: 19820506
coronary MRA; extracardiac findings; MR artifacts; MESA
19.  Magnetic Resonance Imaging Guided Vacuum Assisted Breast Biopsy: A Phantom and Patient Evaluation of Targeting Accuracy 
Purpose
To determine the spatial localization errors of magnetic resonance imaging (MRI) guided core biopsy for breast lesions using the hand-held vacuum assisted core biopsy device in phantoms and patients.
Materials and Methods
Biopsies were done using a 10-gauge hand-held vacuum-assisted core biopsy system (Vacora, Bard, Arizona) on a 1.5 T MRI scanner (Philips Achieva, Best, The Netherlands). A standardized biopsy localization protocol was followed by trained operators for multi-planar planning of the biopsy on a separate workstation. Biopsy localization errors were determined as the distance from needle tip to center of the target in 3 dimensions.
Results
Twenty MRI-guided biopsies of phantoms were performed by 3 different operators. The biopsy target mean size was 6.8 ± 0.6 mm. The overall mean three dimensional (3D) biopsy targeting error was 4.4 ± 2.9 mm. Thirty two MRI breast biopsies performed in 22 patients were reviewed. The lesion mean size was 10.5 ± 9.4 mm. The overall mean 3D localization error was 5.7 ± 3.0 mm. No significant differences between phantom and patients biopsy errors were found (p-value >0.5).
Conclusion
MRI guided hand-held vacuum assisted core biopsy device shows good targeting accuracy and should allow localization of lesions to within approximately 5–6 mm.
doi:10.1002/jmri.21831
PMCID: PMC2735014  PMID: 19629977
Breast cancer; MRI; biopsy; phantom study
20.  Multiple imputation for missing cardiac magnetic resonance imaging data: Results from the Multi-Ethnic Study of Atherosclerosis (MESA) 
The Canadian Journal of Cardiology  2009;25(7):e232-e235.
BACKGROUND:
Cardiac magnetic resonance imaging (MRI) is a non-invasive technique used to accurately and reproducibly measure biological parameters such as left ventricular mass. However, some subjects either refuse or are unable to complete testing, and the impact of excluding these missing data from predictive models is unknown.
METHODS:
Multiple imputation was applied to cardiac MRI data that were previously analyzed using a complete case approach. The model variables – 10 traditional cardiovascular risk factors and five sociodemographic variables – were used as a basis for imputation. Men and women were imputed separately. The primary focus was assessing the change in the cardiovascular predictors of left ventricular geometry and systolic function.
RESULTS:
Although 27% of participants were missing cardiac MRI data, multiple imputation returned results similar to those of a complete case analysis. These results were robust to the point of including additional variables in the imputation analysis above and beyond the model variables. The degree of variance explained by the models increased marginally but the statistical inference was altered for only two predictors out of 53 cardiovascular risk factors using multiple imputation.
DISCUSSION:
The results suggest that the cardiac MRI data in the Multi-Ethnic Study of Atherosclerosis (MESA) do not substantively change when missing data are handled using multiple imputation. Future analyses of cardiac MRI data may consider the complete case approach to be adequate despite the high rate of missing data in this population.
PMCID: PMC2723032  PMID: 19584978
Comparison of methods; Complete case; Magnetic resonance imaging; Multiple imputation
21.  Cardiac CT and MRI guide surgery in impending left ventricular rupture after acute myocardial infarction 
We report the case of a 67 year-old patient who presented with worsening chest pain and shortness of breath, four days post acute myocardial infarction. Contrast enhanced computed tomography of the chest ruled out a pulmonary embolus but revealed an unexpected small subepicardial aneurysm (SEA) in the lateral left ventricular wall which was confirmed on cardiac magnetic resonance imaging. Intraoperative palpation of the left lateral wall was guided by the cardiac MRI and CT findings and confirmed the presence of focally thinned and weakened myocardium, covered by epicardial fat. An aneurysmorrhaphy was subsequently performed in addition to coronary bypass surgery and a mitral valve repair. The patient was discharged home on post operative day eight in good condition and is feeling well 2 years after surgery.
doi:10.1186/1749-8090-4-42
PMCID: PMC2737537  PMID: 19674451

Results 1-21 (21)