Alexander Sevrukov

Electron-Beam Tomography Coronary Artery Calcium and Cardiac Events A 37-Month Follow-Up of 5635 Initially Asymptomatic Low- to Intermediate-Risk Adults

Background—Conventional coronary artery disease (CAD) risk factors fail to explain nearly 50% of CAD events. This study examines the association between electron-beam tomography (EBT) coronary artery calcium (CAC) and cardiac events in initially asymptomatic low- to intermediate-risk individuals, with adjustment for the presence of hypercholesterolemia, hypertension, diabetes, and a history of cigarette smoking. Methods and Results—The study was performed in 8855 initially asymptomatic adults 30 to 76 years old (26% women) who self-referred for EBT CAC screening. Conventional CAD risk factors were elicited by use of a questionnaire. After 37±12 months, information on the occurrence of cardiac events was collected and confirmed by use of medical records and death certificates. In men, events (n=192) were associated with the presence of CAC (RR=10.5, P <0.001), diabetes (RR=1.98, P =0.008), and smoking (RR=1.4, P =0.025), whereas in women, events (n=32) were linked to the presence of CAC (RR=2.6, P =0.037) and not risk factors. The presence of CAC provided incremental prognostic information in addition to age and other risk factors. Conclusions—The association between EBT CAC and cardiac events observed in this study of initially asymptomatic, middle-aged, low to intermediate-risk individuals presenting for screening suggests that in this group, knowledge of the presence of EBT CAC provides incremental information in addition to that defined by conventional CAD risk assessment.

Inflammatory Pseudotumor: The Great Mimicker

OBJECTIVE The purpose of this review is to describe the pathophysiologic findings, differential diagnosis, imaging features, and management of inflammatory pseudotumor in various locations throughout the body. CONCLUSION Inflammatory pseudotumor is a rare benign process mimicking malignant processes and has been found in almost every organ system. Radiologists should be familiar with this entity as a diagnostic consideration to avoid unnecessary surgery.

The prevalence of coronary artery calcium among diabetic individuals without known coronary artery disease

OBJECTIVES We sought to examine the age and gender distribution of coronary artery calcium (CAC) by diabetes status in a large cohort of asymptomatic individuals. BACKGROUND Among individuals with diabetes, coronary artery disease (CAD) is a major cause of morbidity and mortality. Electron-beam tomography (EBT) quantifies CAC, a marker for atherosclerosis. METHODS Screening for CAC by EBT was performed in 30,904 asymptomatic individuals stratified by their self-reported diabetes status, gender, and age. The distribution of CAC across the strata and the association between diabetes and CAC were examined. RESULTS Compared with nondiabetic individuals (n = 29,829), those with diabetes (n = 1,075) had higher median CAC scores across all but two age groups (women 40 to 44 years old and men and women > or =70 years old). Overall, the likelihood of having a CAC score in the highest age/gender quartile was 70% greater for diabetic individuals than for their nondiabetic counterparts. CONCLUSIONS Younger diabetic individuals appear to have calcified plaque burden comparable to that of older individuals without diabetes. These findings call for future research to determine if EBT-CAC screening has an incremental value over the current CAD risk assessment of individuals with diabetes.

Conventional coronary artery disease risk factors and coronary artery calcium detected by electron beam tomography in 30,908 healthy individuals.

PURPOSE Electron beam tomography (EBT) is a noninvasive measure of coronary artery calcium (CAC), a marker for atherosclerosis. In this study we examined the association between conventional risk factors for coronary artery disease (CAD) and CAC. METHODS EBT CAC screening was performed on 30,908 asymptomatic individuals aged 30 to 90 years. Prior to EBT screening, individuals provided demographic and CAD risk factor information. EBT utilized a C-100 EBT scanner, and the amount of CAC was determined using the Agatston scoring method. RESULTS The results of this study demonstrate that for both men and women, all conventional risk factors were significantly associated with the presence of any detectable CAC, and the mean CAC score increased in proportion to the number of CAD risk factors. In age-adjusted (multivariable) logistic regression analysis, cigarette use, histories of hypercholesterolemia, diabetes, and hypertension were each significantly associated with mild to extensive CAC scores (> or =10.0). CONCLUSION CAD risk factors are associated with higher atherosclerotic plaque burden in both men and women. The odds ratios associated with each risk factor relative to the extent of CAC are similar to those reported for the development of clinical CAD, suggesting the existence of an association between CAC (subclinical disease) and CAD (clinical disease).

Coronary calcification and osteoporosis in men and postmenopausal women are independent processes associated with aging

The objective of this study was to investigate whether low bone mass is directly associated with the severity of coronary atherosclerosis in men and postmenopausal women self-referred for evaluation of coronary atherosclerosis and osteoporosis. Low bone mass was evaluated by measurement of bone mineral density (BMD) using quantitative computerized tomography (QCT). Coronary atherosclerosis was evaluated by measurement of coronary calcium (CC) burden using electron beam computerized tomography (EBCT). Using a cross-sectional design, we tested the hypothesis that osteoporosis and coronary atherosclerosis are correlated, age-dependent processes. Study variables were BMD, CC scores, and other known risk factors for osteoporosis and atherosclerosis. Qualifying for the study were 313 postmenopausal women and 167 men. Men had higher baseline CC scores and higher body mass indexes compared to women. In females, those patients with coronary calcification were older and had significantly lower BMD compared to those without calcification. In males, those patients with coronary calcification were older. By univariate correlation analysis, the degree of coronary calcification was inversely associated with BMD in postmenopausal women (P < 0.0001) but not in men. However, after controlling for age, this association was absent for both men and postmenopausal women. Using multivariate logistic regression analysis in women and men separately, age was the only significant predictor of positive CC status and low BMD. Our study suggests that in postmenopausal women and in men, after controlling for age, osteoporosis and coronary atherosclerosis are independent processes.

Serial Electron Beam CT Measurements of Coronary Artery Calcium: Has Your Patient's Calcium Score Actually Changed?

OBJECTIVE The objective of our study was to develop a model for determining the smallest statistically significant change in the coronary artery calcium score (CAC) between serial measurements in a given subject. MATERIALS AND METHODS We assembled a convenience sample of 2,217 pairs of repeated electron beam CT coronary calcium scans acquired in quick succession. Each scan consisted of forty 100-msec, 3-mm sections obtained at 60% of the ECG R-R interval. A single observer quantified calcium in each scan independent of knowledge of calcium quantity in the repeated scan. We then modeled a relationship between the variation of the differences between repeated measurements of calcium and the magnitude of the calcium score and formulated 95% repeatability coefficient equations for the Agatston and volumetric CAC score. The equations allow determining the smallest statistically significant interval change in the calcium score between two serial measurements in a given subject. RESULTS In a subject with measurable CAC at baseline, the smallest statistically significant interval change is +/- (4.930 x square root of baseline Agatston CAC score) or +/- (3.445 x square root of baseline volumetric CAC score). In a subject with no measurable CAC at baseline, a follow-up CAC score exceeding 11.6 Agatston units or 9.5 mm3 qualifies for statistically significant progression. The results were similar in men and women. CONCLUSION By examining repeatability of quantitative electron beam CT measurements of coronary calcium as a function of the magnitude of the calcium score, we developed a model to determine the smallest statistically significant change between serial measurements in a given subject.

Identifying the course of an anomalous left coronary artery using contrast-enhanced electron beam tomography and three-dimensional reconstruction.

Coronary anomalies are a rare but recognized cause of myocardial ischemia and sudden death. Until recently, invasive coronary arteriography was the diagnostic method of choice. However, contrast‐enhanced electron beam tomography has the advantage of three‐dimensional visualization of anomalous coronary arteries. We describe a case of anomalous origin of the left coronary artery. Cathet Cardiovasc Intervent 2002;57:532–536.

Quantitative analysis of vascular heterogeneity in breast lesions using contrast-enhanced 3-D harmonic and subharmonic ultrasound imaging

Ability to visualize breast lesion vascularity and quantify the vascular heterogeneity using contrast-enhanced 3-D harmonic (HI) and subharmonic (SHI) ultrasound imaging was investigated in a clinical population. Patients (n = 134) identified with breast lesions on mammography were scanned using power Doppler imaging, contrast-enhanced 3-D HI, and 3-D SHI on a modified Logiq 9 scanner (GE Healthcare). A region of interest corresponding to ultrasound contrast agent flow was identified in 4D View (GE Medical Systems) and mapped to raw slice data to generate a map of time-intensity curves for the lesion volume. Time points corresponding to baseline, peak intensity, and washout of ultrasound contrast agent were identified and used to generate and compare vascular heterogeneity plots for malignant and benign lesions. Vascularity was observed with power Doppler imaging in 84 lesions (63 benign and 21 malignant). The 3-D HI showed flow in 8 lesions (5 benign and 3 malignant), whereas 3-D SHI visualized flow in 68 lesions (49 benign and 19 malignant). Analysis of vascular heterogeneity in the 3-D SHI volumes found benign lesions having a significant difference in vascularity between central and peripheral sections (1.71 ± 0.96 vs. 1.13 ± 0.79 dB, p <; 0.001, respectively), whereas malignant lesions showed no difference (1.66 ± 1.39 vs. 1.24 ± 1.14 dB, p = 0.24), indicative of more vascular coverage. These preliminary results suggest quantitative evaluation of vascular heterogeneity in breast lesions using contrast-enhanced 3-D SHI is feasible and able to detect variations in vascularity between central and peripheral sections for benign and malignant lesions.

Contrast-enhanced nonlinear 3D ultrasound imaging of breast lesions in a clinical population

The ability to visualize breast lesion vascularity and quantify the vascular heterogeneity using contrast-enhanced 3-D nonlinear ultrasound imaging was investigated in a clinical population. Patients (n = 236) identified with breast lesions on mammography were scanned using power Doppler imaging, contrast-enhanced 3D HI, and 3D SHI on a modified Logiq 9 scanner (GE Healthcare). Time-intensity curve volumes were developed corresponding to ultrasound contrast agent flow in the lesions after being identified in 4D View (GE Medical Systems). Time points corresponding to, wash-in, baseline, peak intensity, and washout of ultrasound contrast agent were identified and used to generate and compare vascular heterogeneity plots for malignant and benign lesions. Vascularity was observed with power Doppler imaging in 93 lesions (69 benign and 24 malignant). The 3D HI showed flow in 8 lesions (5 benign and 3 malignant), whereas 3D SHI visualized flow in 83 lesions (58 benign and 25 malignant). Analysis of vascular heterogeneity in the 3D SHI volumes found benign lesions having a significant difference in vascularity between central and peripheral sections (1.8 ± 0.16 vs. 1.2 ± 0.09 dB, p = 0.0003, respectively), whereas malignant lesions showed no difference (1.7 ± 0.33 vs. 1.3 ± 0.21 dB, p = 0.23), indicative of more vascular coverage. Parametric volumes, that contained a single parametric value for every voxel within the 3D volume in order to visualize localized variations, were generated based on perfusion (PER) and area under the curve (AUC). These maps highlighted the variations in the vascularity for individual voxels in the lesion volume. Finally, a preliminary measure for lesion characterization, based on vascular heterogeneity, achieved an area under the ROC of 0.72. These preliminary results suggest quantitative evaluation of vascular heterogeneity in breast lesions using contrast-enhanced 3D SHI is feasible and able to detect variations in vascularity between central and peripheral sections for benign and malignant lesions to aid in characterization.

4D harmonic and subharmonic contrast-enhanced ultrasound for the characterization of breast masses: Update on a multi-center prospective study

While mammography has high sensitivity in the detection of breast cancer, its low specificity results in a false-positive rate of roughly 80 %. Thus, a secondary tool for the characterization of breast masses would be highly beneficial. This ongoing study investigates the use of 4D harmonic and subharmonic imaging (HI and SHI) for the characterization of breast masses identified by mammography. Patients scheduled for an ultrasound guided biopsy of a mammographically-identified breast mass provided informed consent to undergo a contrast ultrasound study prior to biopsy. Scanning was performed using a modified Logiq 9 scanner with a 4D10L probe (GE Healthcare, Milwaukee, WI). Experimental software provided 4D HI (transmitting 2 cycle pulses at 5 MHz and receiving at 10 MHz) and 4D SHI (transmitting 4 cycle pulses at 5.8 MHz and receiving at 2.9 MHz). Subjects underwent 2D B-mode and power Doppler imaging (PDI), before receiving a 0.25 ml injection of the contrast agent Definity (Lantheus Medical Imaging, N. Billerica, MA) for 4D HI. After 30 minutes, subjects received a second injection of 20 μl/kg (up to 1.25 ml) for 4D SHI of the lesion. To date, 157 women have been enrolled and 149 have completed the study. Incomplete studies resulted from a failure to gain IV access (n=5), equipment malfunction (n=2), and a previously undisclosed contraindication to the contrast agent (n=1; unstable pulmonary status). 3D volume rates ranged from 1.7 Hz (for a 3.7×1.3×2.0 cm lesion) to 6.1 Hz (for a 6x4x6 mm lesion). SHI resulted in improved tissue suppression in 146 cases, equal tissue suppression in 2 cases, and inferior tissue suppression in 1 case relative to HI. Malignancy has been confirmed by pathology in 37 cases. Flow visualization (in all lesions) was evident in 82 cases on PDI, 8 cases on 4D HI, and 68 cases on 4D SHI. Thus, while the diagnostic value has yet to be determined by the radiologists, initial results indicate that 4D SHI provides improved tissue suppression and visualization of flow in breast masses.