JACC Cardiovasc Interv. . 2010; 3(821-7):82

Ntalianis A, Trana C, Muller O, Mangiacapra F, Peace A, De Backer C, De Block L, Wyffels E, Bartunek J, Vanderheyden M, Heyse A, Van Durme F, Van Driessche L, De Jans J, Heyndrickx GR, Wijns W, Barbato E, De Bruyne B.

OBJECTIVES: This study sought to define the additional effective radiation dose, procedural time, and contrast medium needed to obtain fractional flow reserve (FFR) measurements after a diagnostic coronary angiogram.

BACKGROUND: The FFR measurements performed at the end of a diagnostic angiogram allow the obtaining of functional information that complements the anatomic findings.

METHODS: In 200 patients (mean age 66 +/- 10 years) undergoing diagnostic coronary angiography, FFR was measured in at least 1 intermediate coronary artery stenosis. Hyperemia was achieved by intracoronary (n = 180) or intravenous (n = 20) adenosine. The radiation dose (mSv), procedural time (min), and contrast medium (ml) needed for diagnostic angiography and FFR were recorded.

RESULTS: A total of 296 stenoses (1.5 +/- 0.7 stenoses per patient) were assessed. The additional mean radiation dose, procedural time, and contrast medium needed to obtain FFR expressed as a percentage of the entire procedure were 30 +/- 16% (median 4 mSv, range 2.4 to 6.7 mSv), 26 +/- 13% (median 9 min, range 7 to 13 min), and 31 +/- 16% (median 50 ml, range 30 to 90 ml), respectively. The radiation dose and contrast medium during FFR were similar after intravenous and intracoronary adenosine, though the procedural time was slightly longer with intravenous adenosine (median 11 min, range 10 to 17 min, p = 0.04) than with intracoronary adenosine (median 9 min, range 7 to 13 min). When FFR was measured in 3 or more lesions, radiation dose, procedural time, and contrast medium increased.

CONCLUSIONS: The additional radiation dose, procedural time, and contrast medium to obtain FFR measurement are low as compared to other cardiovascular imaging modalities. Therefore, the combination of diagnostic angiography and FFR measurements is warranted to provide simultaneously anatomic and functional information in patients with coronary artery disease.

PMID: 20723854

J Interv Card Electrophysiol. 2010; 28(1):1123-1128

Kapa S, Martinez MW, Williamson EE, Ommen SR, Syed IS, Feng D, Packer DL, Brady PA

OBJECTIVES: Left atrial ablation is increasingly used to treat patients with symptomatic atrial fibrillation (AF). Prior to ablation, exclusion of left atrial appendage (LAA) thrombus is important. Whether ECG-gated dual-source computed tomography (DSCT) provides a sensitive means of detecting LAA thrombus in patients undergoing percutaneous AF ablation is unknown. Thus, we sought to determine the utility of ECG-gated DSCT in detecting LAA thrombus in patients with AF.

METHODS: A total of 255 patients (age 58 +/- 11 years, 78% male, ejection fraction 58 +/- 9%) who underwent ECG-gated DSCT and transesophageal echocardiography (TEE) prior to AF ablation between February 2006 and October 2007 were included. CHADS2 score and demographic data were obtained prospectively. Gated DSCT images were independently reviewed by two cardiac imagers blinded to TEE findings. The LAA was either defined as normal (fully opacified) or abnormal (under-filled) by DSCT.

RESULTS: An under-filled LAA was identified in 33 patients (12.9%), of whom four had thrombus confirmed by TEE. All patients diagnosed with LAA thrombus using TEE also had an abnormal LAA by gated DSCT. Thus, sensitivity and specificity for gated DSCT were 100% and 88%, respectively. No cases of LAA filling defects were observed in patients <51 years old with a CHADS2 of 0.

CONCLUSIONS: In patients referred for AF ablation, thrombus is uncommon in the absence of additional risk factors. Gated DSCT provides excellent sensitivity for the detection of thrombus. Thus, in AF patients with a CHADS2 of 0, gated DSCT may provide a useful stand-alone imaging modality.

PMID: 20809409

J Am Coll Cardiol. 2010; 56(8):617-626

Van Mieghem NM, Piazza N, Anderson RH, Tzikas A, Nieman K, De Laat LE, McGhie JS, Geleijnse ML, Feldman T, Serruys PW, de Jaegere PP

Mitral regurgitation (MR) poses a significant clinical burden in the adult population, which is expected to increase even more with the ever prolonging life expectancies in developed countries. New technology has brought MR, once exclusively the arena of cardiac surgeons, to the attention of interventional cardiologists. A variety of device-oriented transcatheter strategies have evolved in recent years. A comprehensive understanding of mitral valvular anatomy is crucial for the selection of patients, the implementation of devices, and further refinements of these transcatheter techniques if they are eventually to produce procedural and clinical success. The aim of this review is to elucidate the morphology of the mitral valvular complex, integrating key anatomical features into the developing transcatheter options for the treatment of MR.

PMID: 20705218

Clin Radiol. 2010; 65(10):815-822

Cheng Z, Wang X, Duan Y, Wu L, Wu D, Liang C, Liu C, Xu Z

OBJECTIVES: To retrospectively evaluate the clinical value of dual-source computed tomography (DSCT) coronary angiography in the diagnosis of coronary artery anomalies.

METHODS: A large cohort of 3625 consecutive patients, who underwent DSCT coronary angiography in our institute, was reviewed for coronary artery anomalies. All images were evaluated by two experienced readers using axial source images, multi-planar reformations (MPR), maximum intensity projections (MIP) and volume rendering (VR). Coronary artery anomalies were found in 36 patients (male 20, female 16, mean age 48 years, range 15-76 years). Of the 36 patients, 19 patients also underwent conventional coronary angiography (CCA).

RESULTS: The incidence of coronary artery anomalies was 0.99% (36/3625). Six different types of coronary artery anomalies were diagnosed by DSCT coronary angiography: (1) 11 anomalies of the right coronary artery; (2) five anomalies of the left coronary artery; (3) 10 anomalies of the left circumflex artery; (4) two single coronary artery; (5) one anomalous pulmonary origin of the coronary artery; (6) seven coronary artery fistula. Evaluation of the CCA resulted in a precise diagnosis in 53% (10/19) patients.

CONCLUSION: DSCT coronary angiography is a good diagnostic tool to examine coronary artery anomalies.

PMID: 20797468

Circ Arrhythm Electrophysiol. 2010; 3(4):345-350

Thanassoulis G, Massaro JM, O'Donnell CJ, Hoffmann U, Levy D, Ellinor PT, Wang TJ, Schnabel RB, Vasan RS, Fox CS, Benjamin EJ

OBJECTIVES: Obesity represents an important risk factor for atrial fibrillation (AF). We tested the hypothesis that pericardial fat, a unique fat deposit in close anatomic proximity to cardiac structures and autonomic fibers, is associated with prevalent AF.

METHODS: Participants from the Framingham Heart Study underwent multidetector computed tomography from 2002 to 2005. We estimated the association between quantitative pericardial, intrathoracic and visceral adipose tissue volumes (per standard deviation of volume) with prevalent AF adjusting for established AF risk factors (age, sex, systolic blood pressure, blood pressure treatment, PR interval, and clinically significant valvular disease).

RESULTS: Of the 3217 eligible participants (mean age, 50.6+/-10.1 years; 48% women), 54 had a confirmed diagnosis of AF. Pericardial fat but not intrathoracic or visceral abdominal fat was associated with prevalent AF in multivariable-adjusted models (odds ratio per standard deviation of pericardial fat volume, 1.28; 95% confidence intervals, 1.03 to 1.58). Further adjustments for body mass index, heart failure, myocardial infarction, and intrathoracic fat volume did not materially change the association between pericardial fat and AF.

CONCLUSIONS: Pericardial fat was associated with prevalent AF even after adjustment for AF risk factors, including body mass index. If this association is replicated, further investigations into the mechanisms linking pericardial fat to AF are merited.

PMID: 20558845

American Journal or Roentgenology. 2010; 195(3):655661

Jonathon Leipsic, Troy M. LaBounty, Brett Heilbron, James K. Min, G. B. John Mancini, Fay Y. Lin, Carolyn Taylor, Allison Dunning, James P. Earls

OBJECTIVES: The objective of our study was to assess the impact of Adaptive Statistical Iterative Reconstruction (ASIR) on radiation dose and study quality for coronary CT angiography (CTA).

METHODS: We prospectively evaluated 574 consecutive patients undergoing coronary CTA at three centers. Comparisons were performed between consecutive groups initially using filtered back projection (FBP) (n = 331) and subsequently ASIR (n = 243) with regard to patient and scan characteristics, radiation dose, and diagnostic study quality.

RESULTS: There was no difference between groups in the use of prospective gating, tube voltage, or scan length. The examinations performed using ASIR had a lower median tube current than those obtained using FBP (median [interquartile range], 450 mA [350–600] vs 650 mA [531–750], respectively; p < 0.001). There was a 44% reduction in the median radiation dose between the FBP and ASIR cohorts (4.1 mSv [2.3–5.2] vs 2.3 mSv [1.9–3.5]; p < 0.001). After adjustment for scan settings, ASIR was associated with a 27% reduction in radiation dose compared with FBP (95% CI, 21–32%; p < 0.001). Despite the reduced current, ASIR was not associated with a difference in adjusted signal, noise, or signal-to-noise ratio (p = not significant). No differences existed between FBP and ASIR for interpretability per coronary artery (98.5% vs 99.3%, respectively; p = 0.12) or per patient (96.1% vs 97.1%, p = 0.65).

CONCLUSIONS: ASIR enabled reduced tube current and lower radiation dose in comparison with FBP, with preserved signal, noise, and study interpretability, in a large multicenter cohort. ASIR represents a new technique to reduce radiation dose in coronary CTA studies.

PMID:

J Am Coll Cardiol Img . 2010; 3():811-820

Kheng-Thye Ho, Kia-Chong Chua, Ernst Klotz, Christoph Panknin

OBJECTIVES: This study sought to describe a protocol for myocardial perfusion imaging using dipyridamole stress, with 128-slice dual-source computed tomography (CT), and to assess the ability of CT myocardial perfusion imaging (MPI) to detect abnormal flow reserve and infarction in comparison with nuclear MPI (NMPI). CT MPI has not been previously described with the 128-slice dual-source CT scanner, or with the complete evaluation of dynamic time-attenuation curves of the myocardium.

METHODS: Thirty-five patients underwent a stress CT MPI protocol. Complete time-attenuation curves of the myocardium were acquired using a novel scan mode, which acquires prospectively electrocardiogram (ECG)-triggered axial images at 2 rapidly alternating positions. Myocardial blood flow (MBF) values of fixed and reversible defects obtained were compared between rest and stress. Findings on CT MPI were correlated to NMPI. Perfusion defects detected on CT were correlated to coronary stenoses detected on CT angiography (CTA) and invasive coronary angiography (ICA).

RESULTS: There was a 1.5-fold difference between stress (1.21 ± 0.31 cc/cc/min) and rest (0.82 ± 0.22 cc/cc/min) MBF in normal tissue. In reversible defects, MBF was 0.65 ± 0.21 cc/cc/min and 0.63 ± 0.18 cc/cc/min at stress and rest, respectively. In fixed defects, the MBF was 0.57 ± 0.22 cc/cc/min at stress and 0.54 ± 0.23 cc/cc/min at rest. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT MPI for identifying segments with perfusion defects was 0.83, 0.78, 0.79, and 0.82, respectively. ICA results were available for 30 patients. Sensitivity, specificity, PPV, and NPV of CT MPI compared with ICA were 0.95, 0.65, 0.78, and 0.79, respectively. The radiation dose for CT MPI was 9.15 ± 1.32 mSv for the stress scan and 9.09 ± 1.40 mSv for the rest scan.

CONCLUSIONS: Vasodilator-stress CT MPI may be feasible in human subjects at a radiation dose similar to NMPI. It identifies areas of abnormal flow reserve and infarction with a high degree of correlation to NMPI as well as to stenoses detected in CTA and ICA.

PMID:

Int J Cardiovasc Imaging. 2010; 26(6):567-569

Nagao M, Kido T, Watanabe K, Saeki H, Okayama H, Kurata A, Hosokawa K, Higashino H, Mochizuki T

OBJECTIVES: We attempted to assess coronary artery flow using adenosine-stress and dual-energy mode with dual-source CT (DE-CT).

METHODS: Data of 18 patients with suspected coronary arteries disease who had undergone cardiac DE-CT were retrospectively analyzed. The patients were divided into two groups: 10 patients who performed adenosine stress CT, and 8 patients who performed rest CT as controls. We reconstructed an iodine map and composite images at 120 kV (120 kV images) using raw data with scan parameters of 100 and 140 kV. We measured mean attenuation in the coronary artery proximal to the distal portion on both the iodine map and 120 kV images. Coronary enhancement ratio (CER) was calculated by dividing mean attenuation in the coronary artery by attenuation in the aortic root, and was used as an estimate of coronary enhancement. Coronary stenosis was identified as a reduction in diameter of >50% on CT angiogram, and myocardial ischemia was diagnosed by adenosine-stress myocardial perfusion scintigraphy.

RESULTS: The iodine map showed that CER was significantly lower for ischemic territories (0.76 +/- 0.06) or stenosed coronary arteries (0.77 +/- 0.06) than for non-ischemic territories (0.95 +/- 0.21, P = 0.02) or non-stenosed coronary arteries (1.07 +/- 0.33, P < 0.001). The 120 kV images showed no difference in CER between these two groups. Use of CER on the iodine map separated ischemic territories from non-ischemic territories with a sensitivity of 86% and a specificity of 75%.

CONCLUSIONS: Our quantification is the first non-invasive analytical technique for assessment of coronary artery flow using cardiac CT. CER on the iodine map is a candidate method for demonstration of alteration in coronary artery flow under adenosine stress, which is related to the physiological significance of coronary artery disease.

PMID: 20686853

Pacing Clin Electrophysiol. 2010; 33(8):546-555

Girsky MJ, Shinbane JS, Ahmadi N, Mao S, Flores F, Budoff MJ

OBJECTIVES: Cardiovascular computed tomographic angiography (CTA) can visualize the coronary veins. We sought to assess the ability of CTA to facilitate resynchronization therapy (CRT) procedures using a prospective randomized single-center pilot study.

METHODS: Patients underwent CTA for characterization of cardiomyopathy prior to biventricular implantable cardiac-defibrillator implant. Randomization was performed with operator review of the CTA for coronary venous anatomy prior to CRT in one-half of the cases. Invasive coronary venous angiograms were used in all procedures. Analysis included procedure times and utilization of contrast, fluoroscopy, and guide catheters.

RESULTS: Characteristics of the 26 patients enrolled were mean age 55 +/- 11 years, male 76.9%, ischemic etiology 35%, ejection fraction 25 +/- 3%, class III congestive heart failure 100%, and QRS duration 179 +/- 29 ms. Of patients enrolled, 22 had both CTA and procedure initiation. Three patients (two with CTA review and one without CTA review) had aborted procedures due to hemodynamic issues. Analysis of the 22 patients (nine with preprocedure CTA review and 13 without CTA review) demonstrated that preprocedure review of CTA coronary venous anatomy led to significantly decreased procedure times and utilization of contrast, fluoroscopy, and guide catheters.

CONCLUSIONS: Preprocedure review of CTA coronary venous anatomy may lead to decreased procedural times and utilization of contrast, fluoroscopy, and guide catheters. These preliminary results will need to be evaluated in larger heart failure populations undergoing CRT.

PMID: 20579305

Eur Radiol. 2010; 20(9):1045-1054

Karlo C, Leschka S, Goetti RP, Feuchtner G, Desbiolles L, Stolzmann P, Plass A, Falk V, Marincek B, Alkadhi H, Baumüller S

OBJECTIVES: To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition.

METHODS: 120 patients(mean age 68 +/- 13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch(group A; n = 40), non-ECG-gated high-pitch(group B; n = 40) or retrospectively ECG-gated standard-pitch(C; n = 40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated.

RESULTS: Interobserver agreement was good(kappa = 0.64-0.78). Image quality was diagnostic in 38/40 patients(group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p = 0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C(each, p < 0.01). Average image noise was significantly different between all groups(p < 0.05). Mean radiation dose estimates in groups A and B(each; 2.4 +/- 0.3 mSv) were significantly lower compared to group C(17.5 +/- 4.4 mSv; p < 0.01).

CONCLUSIONS: High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition.

PMID: 20677006