Radiation Doses in Patients Undergoing Computed Tomographic Coronary Artery Calcium Evaluation With a 64-Slice Scanner Versus a 256-Slice Scanner.

Computed tomographic coronary artery calcium scanning enables cardiovascular risk stratification; however, exposing patients to high radiation levels is an ongoing concern. New-generation computed tomographic systems use lower radiation doses than older systems do. To quantify comparative doses of radiation exposure, we prospectively acquired images from 220 patients with use of a 64-slice GE LightSpeed VCT scanner (control group, n=110) and a 256-slice GE Revolution scanner (study group, n=110). The groups were matched for age, sex, and body mass index; statistical analysis included t tests and linear regression. The mean dose-length product was 21% lower in the study group than in the control group (60.2 ± 27 vs 75.9 ± 22.6 mGy·cm; P <0.001) and also in each body mass index subgroup. Similarly, the mean effective radiation dose was 21% lower in the study group (0.84 ± 0.38 vs 1.06 ± 0.32 mSv) and lower in each weight subgroup. After adjustment for sex, women in the study group had a lower dose-length product (50.4 ± 23.4 vs 64.7 ± 27.6 mGy·cm) than men did and received a lower effective dose (0.7 ± 0.32 vs 0.9 ± 0.38 mSv) (P=0.009). As body mass index and waist circumference increased, so did doses for both scanners. Our study group was exposed to radiation doses lower than the previously determined standard of 1 mSv, even after adjustment for body mass index and waist circumference. In 256-slice scanning for coronary artery calcium, radiation doses are now similar to those in lung cancer screening and mammography.

Anti-N-methyl-d-aspartate Receptor Encephalitis Related Sinus Node Dysfunction and the Lock-Step Phenomenon.

Described in 2007, anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE) is a rare autoimmune limbic encephalitis affecting young adults (predominantly women of reproductive age) and is a paraneoplastic manifestation of ovarian teratoma in about half of the cases. ANMDARE is characterized by psychiatric changes, neurological changes, autonomic instability and cardiac dysrhythmias. In this report, we present a 36-year-old woman who was 16 weeks pregnant and brought to the hospital with confusion and subsequently had a seizure with Electroencephalography (EEG) demonstrated an extreme delta brush pattern consistent with ANMDARE. Patient developed sinus nodal dysfunction and was also found to have ovarian teratoma, a rather typical presentation for ANMDARE, that is considered a paraneoplastic syndrome for ovarian teratoma. In this report, we highlight the cardiac manifestation of ANMDARE, the pathophysiology associated with autonomic instability, and management strategies of this rare, and largely devastating illness.

Lower Radiation Dosing in Cardiac CT Angiography: The CONVERGE Registry.

Coronary artery disease is the leading cause of morbidity and mortality. Tools have been developed to accurately diagnose and evaluate coronary artery disease. Coronary CT angiography (CCTA) provides detailed imaging to deliver precise analysis and prognostic information. We sought to compare the radiation dose from a 256-detector-row CT scanner with that from a 64-detector-row CT scanner across a similar profile of patients. Methods: Consecutive patients were screened for the Converge Registry study and, after consenting to be included, were enrolled in accordance with an Institutional Review Board-approved protocol. A control group who underwent 64-row CCTA were matched by age, sex, and body mass index (BMI) with a group who underwent 256-row CCTA. Results: We compared 110 patients in each group. We found that mean dose-length product (DLP) was significantly lower in the 256-row group than in the 64-row group (P < 0.05). The radiation dose was reduced by 32% with use of the 256-row scanner for BMIs of 18.5-24.9 (DLP, 111.2 vs. 76.1 mGy-cm [1.56 vs. 1.07 mSv]; P < 0.05). For each BMI subgroup, there was a significant decrease in dose. Regression analysis found that with increasing BMIs, DLP significantly increased for both scanners. Conclusion: The 256-row scanner provided CCTA scans at significantly lower radiation doses than the 64-row scanner in different BMI groups, with all other variables accounted for. Lower radiation exposure along with lower contrast requirements can provide images with high diagnostic accuracy and less risk to the patient.

Lower Radiation Dosing in Cardiac Computed Tomographic Angiography: the CONVERGE Registry.

Intro: Coronary artery disease is the leading cause for morbidity and mortality. Tools have been developed to accurately diagnose and evaluate coronary artery disease. Coronary computed tomographic angiography (CCTA) scans provide detailed imaging along with analysis to in order to deliver precise analysis and prognostic information. We sought to evaluate the radiation doses of the 256 detector CT scanner to a 64 slice scanner across a similar profile of patients. Methods: Consecutive patients were screened, enrolled, and consented for the Converge Registry study, in accordance with the Institutional Review Board (IRB) approved protocol. 110 patients underwent CCTA using the GE Revolution 256 detector CT scanner. We matched patients by age, gender and body mass index (BMI) who underwent 64 slice CT scanning. Results: We compared 110 patients in each group. We found that mean dose length product (DLP, presented also in the tables below in millisieverts (mSv)) was significantly lower in the Revolution 256 detector group compared to the 64 slice control group (p<0.05). The radiation dose was reduced 32% with use of Revolution 256 detector scanner for BMI between 18.5 and 24.9 (DLP = 111.2 vs 76.1; 1.56 vs 1.07 mSv; p<0.05). For each BMI subgroup, there was a significant decrease in dose. Regression analysis found that with the increase in BMI both scanners experienced a significant increase in DLP. Conclusion: We are able to demonstrate that the 256 slice CT scanner is able to provide CCTA scans at significantly lower radiation doses compared to the 64 row scanner at different BMI groups, with all other variables accounted for. Lower radiation exposures along with lower contrast requirements can provide quality imaging with high diagnostic accuracy and less risk to the patient.

Overview of Impella and mechanical devices in cardiogenic shock.

INTRODUCTION: Cardiogenic shock (CS) is a life-threatening condition associated with significant morbidity and mortality. The Impella (Abiomed Inc.) is an axial flow pump on a pigtail catheter that is placed across the aortic valve to unload the left ventricle by delivering non-pulsatile blood flow to the ascending aorta. It is used for high-risk percutaneous coronary intervention and CS. AREAS COVERED: Percutaneous mechanical support devices are placed in a minimally invasive manner and provide life-saving assistance. We review Impella and other percutaneous devices such as intra-aortic balloon pump, TandemHeart, and extracorporeal membrane oxygenation (ECMO) and the evidence supporting their use in the setting of CS. EXPERT COMMENTARY: Impella has been proven to be safe and may be superior to other mechanical support devices in CS.

Risk stratification of non-contrast CT beyond the coronary calcium scan.

Coronary artery calcification (CAC) is a well-known marker for coronary artery disease and has important prognostic implications. CAC is able to provide clinicians with a reliable source of information related to cardiovascular atherosclerosis, which carries incremental information beyond Framingham risk. However, non-contrast scans of the heart provide additional information beyond the Agatston score. These studies are also able to measure various sources of fat, including intrathoracic (eg, pericardial or epicardial) and hepatic, both of which are thought to be metabolically active and linked to increased incidence of subclinical atherosclerosis as well as increased prevalence of type 2  diabetes. Testing for CAC is also useful in identifying extracoronary sources of calcification. Specifically, aortic valve calcification, mitral annular calcification, and thoracic aortic calcium (TAC) provide additional risk stratification information for cardiovascular events. Finally, scanning for CAC is able to evaluate myocardial scaring due to myocardial infarcts, which may also add incremental prognostic information. To ensure the benefits outweigh the risks of a scanning for CAC for an appropriately selected asymptomatic patient, the full utility of the scan should be realized. This review describes the current state of the art interpretation of non-contrast cardiac CT, which clinically should go well beyond coronary artery Agatston scoring alone.

Identification of noncalcified plaque in young persons with diabetes: an opportunity for early primary prevention of coronary artery disease identified with low-dose coronary computed tomographic angiography.

PURPOSE: Coronary computed tomographic angiography (CTA) is a valuable tool for assessing coronary artery disease (CAD). Although statin use is widely recommended for persons with diabetes older than age 40, little is known about the presence and severity of CAD in younger patients with diabetes mellitus (DM). We evaluated coronary artery calcium (CAC) and coronary CTA in young persons with both DM1 and DM2 in an attempt to detect the earliest objective evidence of arteriosclerosis eligible for primary prevention. METHODS AND MATERIALS: We prospectively enrolled 40 persons with DM (25 type 1 and 15 type 2) between the ages of 19 and 35 presenting with diabetes for 5 years or longer. All patients underwent coronary CTA and CAC scans to evaluate for early atherosclerotic disease. Each plaque in the coronary artery was classified as noncalcified or calcified-mixed. We also evaluated all segments with stenosis, dividing them into mild (<50%), moderate (50-70%), and severe (>70%). RESULTS: The average age of the DM1 subjects were 26 ± 4 (SD) years and 30 ± 4 years for DM2 patients (P < .01), with duration of diabetes of 8 ± 5 years and average HbA1c% of 8.7 ± 1.6 (norm = 4.6-6.2). Abnormal scans were present in 57.5%, noncalcified in 35% and calcified-mixed plaque in 22.5%. Persons with DM2 had a higher prevalence of positive coronary CTA scans than DM1: 80% versus 44% (P < .03) and more positive CAC scores 53% versus 4%, (P < .01). The total segment score of 2.1 ± 3.4 (P < .01) and total plaque score 1.9 ± 2.8 (P < .01) were highly correlated to each other. Plaque was almost uniformly absent below age 25, and became increasingly common in individuals over the age of 25 years for both groups. The average radiation exposure was 2.5 ± 1.3 mSv. CONCLUSION: Our study verifies that early CAD can be diagnosed with coronary CTA and minimal radiation exposure in young adults with DM. A negative CAC score was not sufficient to exclude early CAD as we observed a preponderance of noncalcified plaque in this cohort. Coronary CTA in young DM patients older than age 25 may provide earlier identification of disease than does a CAC because only noncalcified plaque is frequently present. Coronary CTA provides an opportunity to consider initiation of earlier primary CAD prevention rather than waiting for the age of 40 as currently recommended by the American Diabetes Association guidelines.

Pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms representing <5% of all pancreatic malignancies with an estimated incidence of 1-1.5 cases/100,000. PNETs are broadly classified as either functional or nonfunctional. Functional PNETs include insulinomas, gastrinomas, vasoactive intestinal peptideomas, glucagonomas, and somatostatinomas. The clinical manifestations associated with these tumors are the result of excessive hormonal secretion and action. The functional nature of these tumors makes pancreatic hormone testing critical not only for initial diagnosis but also for follow-up, because they are important tumor markers. Nonfunctional PNETs typically remain clinically silent until a substantial mass effect occurs. Although the majority of PNETs occur sporadically, it is important to recognize that these tumors may be associated with a variety of familial syndromes and in many cases genetic testing of PNET patients is warranted. This article familiarizes the reader with the clinical presentation and the biochemical, radiologic, and genetic testing indicated for diagnosis and follow-up of patients with PNET.

Coronary artery calcium and plaque association with left ventricular mass, assessed by multi-row detector computed tomography.

INTRODUCTION: Few studies have been published describing the association of coronary plaques and coronary artery calcium (CAC) to left ventricular (LV) mass and LV function using multi-detector computed tomography (MDCT). Coronary plaques can potentially influence the LV function. We sought to evaluate LV mass and function on MDCT and its correlation with CAC and plaque burden in the coronary arteries. METHODS: We included 197 symptomatic patients from the multicenter ACCURACY Study. The LV mass was measured manually using Advantage 4.4 workstation. Interobserver variability of LV mass was assessed using 34 randomly selected studies. LV mass was indexed to the body surface area. The coronary plaque severity was assessed in each segment using MDCT, following the 15 segment American Heart Association model. Plaque and segment scores were calculated accordingly. Statistical analysis using multiple logistic regression analysis was performed. RESULTS: We divided the cohort into those with CAC=0 [n=67 (34%)] and those with CAC greater than 0 [n=130 (66%)]. A significant correlation was found between indexed LV mass and CAC, plaque, and segment scores in both adjusted and unadjusted models. A significant association was observed between nonindexed LV mass with CAC, MDCT plaque score and segment score upon adjusting for various cardiovascular risk factors. A significant correlation was found between hyperlipidemia, hypertension, family history of CAD, and greater than 50% and greater than 70% stenosis on invasive cardiac catheterization with LV mass (all P<0.05). CONCLUSION: To our knowledge, this is the first study evaluating coronary plaque on computed tomographic angiography with LV mass. We were able to show a significant correlation of LV mass with CAC score, and with total plaque and total segment scores. The poor prognosis associated with increased CAC scores may be partially explained by this association with increased LV mass.

Interobserver variations of plaque severity score and segment stenosis score in coronary arteries using 64 slice multidetector computed tomography: a substudy of the ACCURACY trial.

BACKGROUND: Assessing the severity of coronary plaque for the risk stratification and management of coronary artery disease is important. Multidetector computed tomography has been shown to be a useful tool to measure coronary plaque; however, interreader variability is a concern. OBJECTIVE: We measured interobserver variations of plaque severity score (PSS) and segment stenosis score (SSS) as measured by the total plaque severity score (TPS) and total segment stenosis score (TSS). METHODS: Cardiac CT scans (n = 221) of the ACCURACY trial were interpreted by 3 different readers blinded to patient characteristics. PSS (mild, 1; moderate, 2; and severe, 3) and SSS (stenosis 1%-29%, 1; 30%-49%, 2; 50%-69%, 3; and ≥70%, 4) were calculated with the 15-segment American Heart Association model. TPS and TSS were determined by summing the segments for each interpreter. TPS and TSS were compared for correlation and variation among any 2 of the 3 readers. RESULTS: A highly significant correlation was observed among any 2 of the 3 readers for both TPS and TSS. For TPS, the r = 0.91, 0.93, 0.94 (P < 0.001) for A vs B, B vs C, A vs C, respectively, and for TSS, r = 0.91, 0.92, 0.93 (P < 0.001) for A vs B, B vs C, A vs C, respectively. On Bland Altman plot, the mean difference between the scores of any 2 readers was 3.33 ± 3.93, 1.65 ± 2.88, and 1.68 ± 2.92 for TPS and 4.19 ± 4.73, 2.54 ± 4.02, and 1.65 ± 3.18 for TSS. CONCLUSION: Semiquantitative measures of coronary plaque burden, including the TPS and TSS, can be determined with a high degree of interobserver agreement, suggesting their potential role as tools to aid in the assessment of coronary heart disease.

The degree of stenosis on cardiac catheterization compared to calcified coronary segments on multi-detector row cardiac computed tomography MDCT.

RATIONALE AND OBJECTIVES: Cardiac computed tomography is increasingly being used to assess the degree of stenosis in coronary arteries. It has been shown in multiple studies to have high negative predictive value for obstructive disease compared to invasive cardiac catheterization (ICA). However, calcified segments are interpreted differently in each study. The aim of this study was to examine the association of calcified plaques on multi-detector row cardiac computed tomography (MDCT) with the degree of stenosis on ICA. MATERIALS AND METHODS: A total of 129 consecutive patients who underwent coronary evaluation on MDCT and also underwent ICA within 1 month of MDCT were included in the study. Each segment in the coronary artery was classified as mixed, calcified, or noncalcified. All segments with calcified plaque were evaluated, further classifying them as mild, moderate, or severe, and obstructive disease on ICA was used as the reference standard, in a blinded fashion. RESULTS: The average age of the patients was 60.8 9.5 years. A total of 379 calcified segments were included in the study. Among these segments, 363 (95.8%) were found to be nonobstructive (<70% stenosis) on ICA. Calcifications were categorized as mild, moderate, and severe in 283 (74.7%), 58 (15.3%), and 38 (10.0%) segments, respectively. When calcium was incomplete in the cross-section of the lumen (mild or moderate calcification), 98.5% of these segments (336 of 341) were associated with nonobstructive disease, decreasing to 71% with severe calcification. CONCLUSION: Calcified plaques seen on MDCT were commonly associated with nonobstructive disease on invasive angiography. Increasing focal calcification increased the likelihood of obstructive disease, but only 29% of severe segments were associated with significant obstructive disease.