Triple rule-out CT in the emergency department: protocols and spectrum of imaging findings.

Triage decisions in patients suffering from acute chest pain remain a challenge. The patient's history, initial cardiac enzyme levels, or initial electrocardiograms (ECG) often do not allow selecting the patients in whom further tests are needed. Numerous vascular and non-vascular chest problems, such as pulmonary embolism (PE), aortic dissection, or acute coronary syndrome, as well as pulmonary, pleural, or osseous lesions, must be taken into account. Nowadays, contrast-enhanced multi-detector-row computed tomography (CT) has replaced previous invasive diagnostic procedures and currently represents the imaging modality of choice when the clinical suspicion of PE or acute aortic syndrome is raised. At the same time, CT is capable of detecting a multitude of non-vascular causes of acute chest pain, such as pneumonia, pericarditis, or fractures. Recent technical advances in CT technology have also shown great advantages for non-invasive imaging of the coronary arteries. In patients with acute chest pain, the optimization of triage decisions and cost-effectiveness using cardiac CT in the emergency department have been repetitively demonstrated. Triple rule-out CT denominates an ECG-gated protocol that allows for the depiction of the pulmonary arteries, thoracic aorta, and coronary arteries within a single examination. This can be accomplished through the use of a dedicated contrast media administration regimen resulting in a simultaneous attenuation of the three vessel territories. This review is intended to demonstrate CT parameters and contrast media administration protocols for performing a triple rule-out CT and discusses radiation dose issues pertinent to the protocol. Typical life-threatening and non-life-threatening diseases causing acute chest pain are illustrated.

Conventional radiography and computed tomography of cardiac assist devices.

Patients intended for circulatory support by cardiac assist devices (CAD) usually suffer from end-stage acute or chronic heart failure. Since the introduction of CAD in 1963 by DeBakey and coworkers, the systems have gone through a substantial evolution and have been increasingly used in the intervening decades. The spectrum of CAD includes a variety of systems serving to assist the systolic function of the left ventricle, the right ventricle, or both. Conventional radiography and multislice spiral computed tomography (CT) are the most commonly used radiological techniques for imaging patients with a CAD. CT is very useful for evaluating CAD systems by using both two- and three-dimensional reconstructions of the volumetric data sets. The two techniques together allow for the comprehensive assessment of patients with devices by imaging the in- and outflow cannulae, the anastomoses, the position of the pump, as well as associated complications. A close collaboration with cardiac surgeons with expertise in the field of circulatory support is deemed necessary for adequate image interpretation. This article describes the technical diversity of the currently available CAD systems. The imaging characteristics on conventional radiography and multislice spiral CT as well as the typical complications of their use are demonstrated.

Diagnostic accuracy of high-pitch dual-source CT for the assessment of coronary stenoses: first experience.

OBJECTIVES: The objective was to prospectively investigate the diagnostic accuracy of high-pitch (HP) dual-source computed tomography coronary angiography (CTCA) compared with catheter coronary angiography (CCA) for the diagnosis of significant coronary stenoses. METHODS: Thirty-five patients (seven women; mean age 62 ± 8 years) underwent both CTCA and CCA. CTCA was performed with a second-generation dual-source CT system permitting data acquisition at an HP of 3.4. Patients with heart rates >60 bpm were excluded from study enrolment. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a four-point scale (1: excellent to 4: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). CCA served as the standard of reference. Radiation dose values were calculated using the dose-length product. RESULTS: Diagnostic image quality was found in 99% of all segments (455/459). Non-diagnostic image quality occurred in a single patient with a sudden increase in heart rate immediately before and during CTCA. Taking segments with non-evaluative image quality as positive for disease, the sensitivity, specificity and positive and negative predictive values were 94, 96, 80 and 99% per segment and 100, 91, 88 and 100% per patient. The effective radiation dose was on average 0.9 ± 0.1 mSv. CONCLUSION: In patients with heart rates ≤60 bpm, CTCA using the HP mode of the dual-source CT system is associated with high diagnostic accuracy for the assessment of coronary artery stenoses at sub-milli-Sievert doses.

Atrial myxomas and thrombi: comparison of imaging features on CT.

OBJECTIVE: The purpose of our study was to compare the imaging features of atrial myxomas and thrombi using CT and to assess the accuracy of CT for determining the origin of myxomas in comparison with surgical findings. MATERIALS AND METHODS: From July 2006 until June 2008, 23 patients (15 women, eight men; mean age, 63 +/- 14 years) with atrial myxomas (n = 13) and thrombi (n = 11) who underwent dual-source CT coronary angiography were included in this retrospective study. Two independent and blinded readers evaluated quantitative (CT attenuation and size) and qualitative (location, origin, shape, mobility, prolapse, and calcifications) parameters at CT. The shape and origin of myxomas were compared with the findings at surgery. RESULTS: No significant differences regarding the CT attenuation of myxomas in comparison with thrombi were found (43 +/- 14 HU vs 57 +/- 30 HU; p = 0.23). Myxomas were significantly larger than thrombi (33 +/- 16 mm vs 21 +/- 7 mm; p < 0.05). The lesions were found equally in the left and right atria (p = 0.11). The origin (p < 0.001), shape (p < 0.05), mobility (p < 0.01), and occurrence of prolapse (p < 0.01) differed significantly between the lesions. Calcifications did not differ between the lesions (p = 0.2). In comparison with surgery, the origin of myxomas was correctly evaluated by CT in 11 of 13 patients (fossa ovalis, n = 5; interatrial septum, n = 4; and lateral atrial wall, n = 2), whereas CT misclassified the origin of two myxomas (posterior and lateral wall left atria at CT vs fossa ovalis at surgery). CONCLUSION: Atrial myxomas and thrombi can be differentiated by their distinguishing features of size, origin, shape, mobility, and prolapse. CT is accurate in determining the origin of myxomas but may fail in some cases.

Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.

PURPOSE: To assess the diagnostic performance of dual-energy dual-source computed tomography (CT) in the detection of endoleaks after endovascular abdominal aortic aneurysm (AAA) repair. MATERIALS AND METHODS: This study was local ethics board approved, and written informed consent was obtained from all patients. One hundred eighteen patients (21 women, 97 men; mean age, 74 years +/- 8 [standard deviation]) underwent follow-up dual-energy dual-source CT during the nonenhanced, arterial, and delayed phases after AAA repair. Delayed phase CT images were acquired in the dual-energy mode for reconstruction of virtual nonenhanced images. Two blinded and independent readers evaluated the data for the presence or absence of endoleaks during three reading sessions: Standard nonenhanced, arterial phase, and delayed phase images were read during session A; virtual nonenhanced, arterial phase, and delayed phase images, during session B; and virtual nonenhanced and delayed phase images, during session C. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, with the session A image data set as the reference standard. Radiation dose parameters were estimated. RESULTS: Reading session A revealed that 52 (44%) of 118 patients had endoleaks. Overall sensitivity, specificity, NPV, and PPV for CT endoleak detection during sessions B and C were identical: 100%, 97%, 100%, and 96%, respectively. The accuracy of the session B and session C readings was not significantly different from that of the session A reading (P = .50). The effective radiation dose in the image acquisition protocol involving one dual-energy scan was significantly (P < .001) lower than the effective doses in the protocols involving standard triple-phase scanning (mean difference, 61%) and standard nonenhanced and delayed phase scanning (mean difference, 41%). CONCLUSION: Compared with standard protocols, one dual-energy dual-source CT scan performed during the delayed phase with reconstruction of virtual nonenhanced images enables detection of endoleaks after endovascular AAA repair with high accuracy and a considerably lower radiation dose.

Dual-energy contrast-enhanced computed tomography for the detection of urinary stone disease.

OBJECTIVES: To assess the value of dual-energy contrast-enhanced computed tomography (CT) imaging for the detection of urinary stone disease using dual-source CT. MATERIALS AND METHODS: Forty consecutive patients (mean age 46.6 +/- 16.2 years, range 27-85 years) suspected of having urinary stone disease underwent dual-source CT of the urinary tract. A 3-phasic CT scan protocol consisting of a standard unenhanced scan, a nephrographic, and an excretory phase of contrast enhancement was performed. The nephrographic phase scan was acquired in the dual-energy mode (80 kV/400 mA and 140 kV/95 mA) allowing reconstruction of virtual unenhanced images. Two blinded readers independently compared standard and virtual unenhanced CT for the number, size, and location of urinary stones. Measurements of anteroposterior abdominal diameters were performed to determine abdominal obesity. RESULTS: Standard unenhanced CT revealed 35 uroliths in 18 of the 40 patients (18 of 40; 45%), virtual unenhanced CT demonstrated 26 uroliths in 15 of the 40 patients (15 of 40; 38%) ([kappa] value 0.89). Three false-negative and no false-positive ratings occurred using virtual unenhanced CT, and false-negative ratings solely occurred in obese patients. Sensitivity, specificity, positive predictive, and negative predictive values for virtual unenhanced CT for the diagnosis of urinary stone disease were 83%, 100%, 100%, and 88%, respectively. CONCLUSIONS: Virtual unenhanced CT images reconstructed from contrast-enhanced dual-energy CT allow detection of urinary stones with good sensitivity and excellent specificity, but sensitivity is decreased in abdominal obese patients.

Flow and wall shear stress in end-to-side and side-to-side anastomosis of venous coronary artery bypass grafts.

PURPOSE: Coronary artery bypass graft (CABG) surgery represents the standard treatment of advanced coronary artery disease. Two major types of anastomosis exist to connect the graft to the coronary artery, i.e., by using an end-to-side or a side-to-side anastomosis. There is still controversy because of the differences in the patency rates of the two types of anastomosis. The purpose of this paper is to non-invasively quantify hemodynamic parameters, such as mass flow and wall shear stress (WSS), in end-to-side and side-to-side anastomoses of patients with CABG using computational fluid dynamics (CFD). METHODS: One patient with saphenous CABG and end-to-side anastomosis and one patient with saphenous CABG and side-to-side anastomosis underwent 16-detector row computed tomography (CT). Geometric models of coronary arteries and bypasses were reconstructed for CFD analysis. Blood flow was considered pulsatile, laminar, incompressible and Newtonian. Peri-anastomotic mass flow and WSS were quantified and flow patterns visualized. RESULTS: CFD analysis based on in-vivo CT coronary angiography data was feasible in both patients. For both types of CABG, flow patterns were characterized by a retrograde flow into the native coronary artery. WSS variations were found in both anastomoses types, with highest WSS values at the heel and lowest WSS values at the floor of the end-to-side anastomosis. In contrast, the highest WSS values of the side-to-side anastomosis configuration were found in stenotic vessel segments and not in the close vicinity of the anastomosis. Flow stagnation zones were found in end-to-side but not in side-to-side anastomosis, the latter also demonstrating a smoother stream division throughout the cardiac cycle. CONCLUSION: CFD analysis of venous CABG based on in-vivo CT datasets in patients was feasible producing qualitative and quantitative information on mass flow and WSS. Differences were found between the two types of anastomosis warranting further systematic application of the presented methodology on multiple patient datasets.

Visualization of congenital thoracic vascular anomalies using multi-detector row computed tomography and two- and three-dimensional post-processing.

Anomalies of the vascular system are caused by false embryogenesis and are therefore present from birth. Single-detector row spiral computed tomography angiography (CTA) and multi-detector row computed tomography angiography (MDCTA) have gained increasing importance in the non-invasive assessment of vascular pathologies and replace conventional angiography in many cases. High-resolution volumetric datasets that are acquired during a single breath-hold give the possibility of two- (2D) and three-dimensional (3D)-post-processing. Due to post-processing, even complex vascular malformations are visualized in an understandable way. Furthermore, CTA, in contrast to conventional angiography, depicts not only the vascular structures but also allows assessment of the surrounding anatomical structures. We present cases of rare congenital anomalies of the thoracic vessels using MDCT with special respect to 2D- and 3D-post-processing.

Image quality of volume rendering of the bronchial tree: Kymogram-gated versus retrospectively ECG-gated and non-gated multi-row detector CT.

RATIONALE AND OBJECTIVE: To compare the image quality of three different heart-cycle-synchronized computed tomography (CT) reconstruction algorithms for volume-rendered (VR) 3D visualization of the bronchial tree. MATERIALS AND METHODS: Kymogram-gated, retrospectively ECG-gated, and non-ECG-gated reconstructions of the bronchial tree were performed from 4-detector-row CT data in 10 subjects. The raw data were reconstructed in 10 phases of the cardiac cycle using ECG-gated and kymogram-gated technique, respectively. For both reconstructions, the optimal artifact-free diastolic phase was determined. VR reconstructions of the bronchial tree were generated from these two data sets and from the non-gated data. Stairstep artifacts of the main bronchi, artifacts in the lung parenchyma, and the extent of bronchial tree visualization were rated by two blinded, independent readers. RESULTS: Kymogram-gated reconstruction showed stairstep artifacts in the main bronchi to the same extent as non-gated reconstruction, but less compared to ECG-gated reconstruction (P < .001). Artifacts in the lung parenchyma were similar with kymogram-gated and non-gated reconstruction, but less compared to ECG-gated reconstruction (P < 0.01). Kymogram-gated reconstruction showed no differences in visualization of segmental and subsegmental bronchi compared to ECG-gated reconstruction, but was inferior to the non-gated reconstruction (P < 0.05). CONCLUSION: Kymogram-gated reconstruction of CT data results in fewer artifacts when compared to the ECG-gated algorithm. Best visualization of the bronchial tree at a low artifact level is obtained with non-gated CT data. It remains therefore the method of choice for VR 3D data post-processing of the bronchial tree.

Coarctation and aorto-aortic bypass: three-dimensional post-processing using multidetector row computed tomography.

We present the case of a 61-year-old man with a history of dyspnea and disparity in blood pressure of the arms and legs due to a stenotic biscupid aortic valve and a hemodynamically relevant restenosis of a resected coarctation. The coarctation was treated with an extra-anatomic transdiaphragmal aorto-aortic bypass graft. At the same time, the biscupid aortic valve was replaced. Postoperative follow-up contrast-enhanced multidetector row computed tomography (MDCT) and three-dimensional (3D) postprocessing of the axial data sets using the volume-rendering technique was performed. This case of complex vascular structures demonstrates the potency of MDCT combined with the 3D visualization technique.

Effects of exercise training on left ventricular volumes and function in patients with nonischemic cardiomyopathy: application of magnetic resonance myocardial tagging.

BACKGROUND: Exercise training is now an accepted component of the therapeutic regimen in patients with heart failure and underlying ischemia, but few data are available on the effects of training in patients with nonischemic dilated cardiomyopathy. METHODS: Twenty-four patients (mean age 55 +/- 9 years, mean ejection fraction 26.6% +/- 10%) were randomized to an exercise (n = 12) or a control (n = 12) group. Patients in the exercise group underwent 5 45-minute sessions of supervised training per week. Before and after the 2-month study period, exercise testing with respiratory gas exchange and lactate analysis was performed, left ventricular volumes and ejection fraction were measured with magnetic resonance imaging, and left ventricular rotation and relaxation velocities were measured with a novel magnetic resonance imaging tagging technique. RESULTS: Training resulted in increases in peak oxygen uptake (VO2) (21.7 +/- 4 mL/kg/min to 25.3 +/- 5 mL/kg/min, P <.05) and VO2 at the lactate threshold (12.8 +/- 4 mL/kg/min to 19.0 +/- 5 mL/kg/min, P <.01). No differences were observed within or between groups in left ventricular end-diastolic volume, end-systolic volume, or ejection fraction. Velocity of left ventricular rotation during systole was unchanged in both groups, and relaxation velocity was higher after training in the exercise group (21.2 +/- 5 degrees/s versus 29.7 +/- 12 degrees/s, P <.05). CONCLUSION: Training resulted in increases in peak VO2 and VO2 at the lactate threshold. Left ventricular volumes and systolic function (ie, ejection fraction and rotation velocity) were unchanged with training, suggesting that training in patients with dilated cardiomyopathy does not lead to further myocardial damage. However, the increase in relaxation velocity after exercise training indicates an improvement in diastolic function. The latter finding suggests an additional potential benefit of exercise training in patients with dilated cardiomyopathy.

Effects of bisoprolol fumarate on left ventricular size, function, and exercise capacity in patients with heart failure: analysis with magnetic resonance myocardial tagging.

BACKGROUND: Recent data suggest that beta-blockers can be beneficial in subgroups of patients with chronic heart failure (CHF). For metoprolol and carvedilol, an increase in ejection fraction has been shown and favorable effects on the myocardial remodeling process have been reported in some studies. We examined the effects of bisoprolol fumarate on exercise capacity and left ventricular volume with magnetic resonance imaging (MRI) and applied a novel high-resolution MRI tagging technique to determine myocardial rotation and relaxation velocity. METHODS: Twenty-eight patients (mean age, 57 +/- 11 years; mean ejection fraction, 26 +/- 6%) were randomized to bisoprolol fumarate (n = 13) or to placebo therapy (n = 15). The dosage of the drugs was titrated to match that of the the Cardiac Insufficiency Bisoprolol Study protocol. Hemodynamic and gas exchange responses to exercise, MRI measurements of left ventricular end-systolic and end-diastolic volumes and ejection fraction, and left ventricular rotation and relaxation velocities were measured before the administration of the drug and 6 and 12 months later. RESULTS: After 1 year, heart rate was reduced in the bisoprolol fumarate group both at rest (81 +/- 12 before therapy versus 61 +/- 11 after therapy; P <.01) and peak exercise (144 +/- 20 before therapy versus 127 +/- 17 after therapy; P <.01), which indicated a reduction in sympathetic drive. No differences were observed in heart rate responses in the placebo group. No differences were observed within or between groups in peak oxygen uptake, although work rate achieved was higher (117.9 +/- 36 watts versus 146.1 +/- 33 watts; P <.05) and exercise time tended to be higher (9.1 +/- 1.7 minutes versus 11.4 +/- 2.8 minutes; P =.06) in the bisoprolol fumarate group. A trend for a reduction in left ventricular end-diastolic volume (-54 mL) and left ventricular end-systolic volume (-62 mL) in the bisoprolol fumarate group occurred after 1 year. Ejection fraction was higher in the bisoprolol fumarate group (25.0 +/- 7 versus 36.2 +/- 9%; P <.05), and the placebo group remained unchanged. Most changes in volume and ejection fraction occurred during the latter 6 months of treatment. With myocardial tagging, insignificant reductions in left ventricular rotation velocity were observed in both groups, whereas relaxation velocity was reduced only after bisoprolol fumarate therapy (by 39%; P <.05). CONCLUSION: One year of bisoprolol fumarate therapy resulted in an improvement in exercise capacity, showed trends for reductions in end-diastolic and end-systolic volumes, increased ejection fraction, and significantly reduced relaxation velocity. Although these results generally confirm the beneficial effects of beta-blockade in patients with chronic heart failure, they show differential effects on systolic and diastolic function.

Vascular emergencies of the thorax after blunt and iatrogenic trauma: multi-detector row CT and three-dimensional imaging.

Multi-detector row computed tomographic (CT) angiography is an effective modality for vascular imaging in the thorax. It allows acquisition of high-resolution data sets during a single breath hold, making it the preferred method for evaluation of patients with acute vascular disease. In contrast to conventional angiography, multirow CT angiography not only depicts the vessels but also allows assessment of adjacent structures. Multirow CT angiography with two- and three-dimensional reformation can be used to diagnose vascular emergencies of the thorax after blunt and iatrogenic trauma. These include incomplete and complete aortic rupture; traumatic aortic dissection; arterial dissection and rupture after minor trauma in patients with Ehlers-Danlos syndrome; traumatic intramural hematoma; pseudoaneurysm after endovascular repair; injuries due to Swan-Ganz catheters; complications of central venous cannulation, pacemaker implantation, and percutaneous pericardial drainage; and foreign-body embolism. The diagnoses can be established with multirow CT angiography in the emergency department. Thus, the time to diagnosis can be considerably decreased by obviating conventional angiography. Knowledge of the CT findings in various vascular conditions is essential to make use of multirow CT angiography in combination with two- and three-dimensional reformation as an efficient and accurate diagnostic tool in emergency radiology.

Computed tomography of the lung in the high-pitch mode: is breath holding still required?

OBJECTIVES: To prospectively investigate whether the high-pitch mode (HPM) for computed tomography (CT) enables the diagnostic visualization of the lung parenchyma without suspended respiration. MATERIALS AND METHODS: A total of 40 consecutive patients (age, 67 ± 11 years) underwent 128-slice dual-source CT of the chest including nonenhanced, arterial, and venous phase of contrast. CT was performed in the HPM with a pitch of 3.2 during continuous breathing (group A) and during breath-hold (group B), and at standard pitch of 1 during deep-inspiratory breath-hold (group C). The 3 protocols were scanned in a random order in each patient. Two blinded readers independently assessed the image quality of 5 regions in both the lungs using a semiquantitative 3-point score. Image noise was measured as the standard deviation of attenuation. Presence and size of pulmonary nodules were noted and measured on each CT dataset. Lung volume was measured using dedicated semi-automated segmentation software. RESULTS: Interobserver agreement for image quality ratings was excellent (κ = 0.91). There were no significant differences in the number of lung regions having an image quality other than excellent between group A (2.5%) and B (1.5%, P = 0.48), whereas significantly less regions had impaired image quality in group B compared with group C (5.5%, P < 0.01). Image quality impairment in group C was because of breathing in 36% and cardiac pulsation in 64%. Image noise in group C (9 ± 2 HU) was significantly lower than that in group B (30 ± 2 HU, P < 0.001) whereas no significant difference was found between group A and B (P = 0.52). There were no significant differences for the depiction (P = 1.0) and size (P = 0.94) of lung nodules among the 3 modes. Average lung volume in group A was 75% ± 15% of that in deep inspiration (group B/C) being significantly smaller (P < 0.05). Estimated effective radiation doses in group C and group B were 5.8 ± 0.5 mSv and 1.6 ± 0.1 mSv, respectively. CONCLUSIONS: CT of the lung can be accomplished using the HPM at a low radiation dose with a diagnostic image quality even without suspended respiration.

Triple rule-out CT in patients with suspicion of acute pulmonary embolism: findings and accuracy.

RATIONALE AND OBJECTIVES: The aim of this study was to prospectively investigate the diagnostic value of triple rule-out computed tomography (CT) in patients suspected of having acute pulmonary embolism (PE). MATERIALS AND METHODS: A total of 125 patients with suspicion of PE, of whom 14 patients had the additional clinical suspicion of acute aortic syndrome, underwent electrocardiogram-gated triple rule-out dual-source CT. The contrast media application protocol was adjusted to obtain a homogenous attenuation of the pulmonary arteries, thoracic aorta, and coronary arteries. The diagnostic performance of triple rule-out CT was assessed by using adjudicated discharge diagnoses as reference standards. RESULTS: A total of 161 adjudicated cardiovascular discharge diagnoses were made in the 125 patients (including all true-positive and true-negative findings): acute PE was found in 26 (21%) and was excluded by CT in 99 (79%), coronary artery disease was found in 3 (3%) and was excluded by catheter angiography in 9 (6%), left ventricular systolic dysfunction was found in 2 (2%) and was excluded by echocardiography in 8 (6%), and acute aortic syndrome was found in 5 (4%) and was excluded by CT in 9 (7%) patients. Nonvascular chest disease was found in 34 (27%) and included pneumonia (n = 17), neoplasms (n = 5), fractures/osteolysis (n = 3), pericarditis (n = 2), and post-pneumonectomy syndrome (n = 1). Triple rule-out CT was normal in 53 (42%) patients. Overall sensitivity, specificity, and positive and negative predictive value of triple rule-out CT for cardiovascular disease were 100% (95% confidence interval [CI] 90-100%), 98% (95%CI 94-100%), 95% (95%CI 82-99%), and 100% (95%CI 97-100%, respectively). CONCLUSIONS: Triple rule-out CT is feasible in patients with suspicion of PE, reveals a wide range of vascular and non-vascular chest disease, and offers an excellent overall diagnostic performance.

Multislice computed tomography in infective endocarditis: comparison with transesophageal echocardiography and intraoperative findings.

OBJECTIVES: The aim of this study was to assess the value of multislice computed tomography (CT) for the assessment of valvular abnormalities in patients with infective endocarditis (IE) in comparison with transesophageal echocardiography (TEE) and intraoperative findings. BACKGROUND: Multislice CT has recently shown promising data regarding valvular imaging in a 4-dimensional fashion. METHODS: Thirty-seven consecutive patients with clinically suspected IE were examined with TEE and 64-slice CT or dual-source CT. Twenty-nine patients had definite IE and underwent surgery. RESULTS: The diagnostic performance of CT for the detection of evident valvular abnormalities for IE compared with TEE was: sensitivity 97%, specificity 88%, positive predictive value (PPV) 97%, and negative predictive value (NPV) 88% on a per-patient basis (n = 37; excellent intermodality agreement kappa = 0.84). CT correctly identified 26 of 27 (96%) patients with valvular vegetations and 9 of 9 (100%) patients with abscesses/pseudoaneurysms compared with the intraoperative specimen. On a per-valve-based analysis, diagnostic accuracy for the detection of vegetations and abscesses/pseudoaneurysms compared with surgery was: sensitivity 96%, specificity 97%, PPV 96%, NPV 97%, and sensitivity 100%, specificity 100%, PPV 100%, NPV 100%, respectively, without significant differences as compared with TEE. Vegetation size measurements by CT correlated (r = 0.95; p <0.001) with TEE (mean 7.6 +/- 5.6 mm). The mobility of vegetations was accurately diagnosed in 21 of 22 (96%) patients with CT, but all of 4 leaflet perforations (

Mitral annular shape, size, and motion in normals and in patients with cardiomyopathy: evaluation with computed tomography.

OBJECTIVE: To assess prospectively, in healthy subjects and in patients with dilated cardiomyopathy (DCM) and hypertrophic obstructive cardiomyopathy (HOCM), the 3-dimensional (3D) shape, size, and motion of the mitral annulus (MA) using computed tomography (CT). MATERIALS AND METHODS: Twenty patients with no cardiac abnormalities (referred to as normals), 15 with DCM, and 15 with HOCM as determined by echocardiography underwent contrast-enhanced, retrospectively electrocardiography (ECG)-gated 64-slice CT of the heart. The MA was manually segmented in 10% steps of the RR interval with dedicated 3D software employing the point-wrap algorithm. The MA shape, area size, change of the MA area, and apicobasal MA motion throughout the cardiac cycle was determined and compared between the groups. Intercommissural distances were measured with CT and compared with findings during surgery in 9 patients undergoing ring annuloplasty. RESULTS: The MA was nonplanar in all phases and subjects, being largest in diastole and smallest in systole. The MA area was significantly (P < 0.001) larger in patients with DCM (11.5 +/- 4.1 cm/m) as compared with normals (5.5 +/- 0.9 cm/m) and HOCM (4.7 +/- 0.9 cm/m). The change of MA area throughout the cardiac cycle was significantly (P < 0.017) smaller in patients with DCM (12.2 +/- 3.3%/m) as compared with normals (20.0 +/- 7.9%/m) and HOCM (20.5 +/- 7.7%/m). The mean apicobasal motion was significantly (P < 0.017) smaller in patients with DCM (2.2 +/- 1.0 mm/m) as compared with normals (3.6 +/- 0.8 mm/m) and HOCM (2.7 +/- 0.7 mm/m). Intercommissural distances as determined by CT showed a good correlation (r = 0.68, P < 0.05) with intraoperative measurements (mean difference, 0.44 mm; limits of agreement, -2.73-3.62 mm). CONCLUSION: Our study provides in vivo human data on the 3D shape, size, and motion of the MA in healthy subjects. Significant changes in size and motion of the MA were noted in patients with HOCM.

Reference values for quantitative left ventricular and left atrial measurements in cardiac computed tomography.

To assess reference values for left ventricular (LV) and left atrial (LA) dimensions, global LV function, and LV-myocardial mass for cardiac CT. We examined 120 subjects undergoing a coronary angiography using 64-slice and dual-source CT. All individuals had a low cardiovascular risk, normal ECG, negative biomarkers, and a normal cardiac CT examination. All subjects had a negative medical history of cardiovascular disease both on admission and at clinical 6-month follow-up. The following measurements were obtained: septal wall thickness (SWT), posterior wall thickness (PWT), LV inner diameter (LVID), LA anterior posterior diameter (LAD(sys)), end-systolic volume (ESV), and end-diastolic volume (EDV), LV-myocardial mass (LVMM). We found significant gender-related differences for all LV dimensions (SWT(sys), SWT(dia),PWT(sys),PWT(dia),LVID(sys),LVID(dia)). LAD(sys) showed no significant difference between males and females. Significant differences were found for global LV functional parameters including ESV, EDV, and SV, whereas no significant differences were found for the EF. LV-myocardial mass parameters showed significant gender-related differences. No significant correlation was found between any of these parameters and age. All data were transferred to percentile ranks. This study provides gender-related reference values and percentiles for LV and LA quantitative measurements for cardiac CT and should assist in interpreting results.

Dual-energy computed tomography for the differentiation of uric acid stones: ex vivo performance evaluation.

We assessed the potential of dual-energy computed tomography (CT) for the differentiation between uric acid (UA)-containing and non-UA-containing urinary stones. Forty urinary stones of 16 different compositions in two sizes (or=5 mm) were examined in an ex vivo model. Thirty stones consisted of pure calcium oxalate (whewellite or wheddellite), calcium phosphate (apatite, brushite, or vaterite), ammonium magnesium phosphate (struvite), UA, ammonium acid urate, ammonium phosphate, sodium hydrogen urate, or cystine, and ten stones were of mixed composition (UA-sodium hydrogen urate, whewellite-urate, wheddellite-urate, whewellite-brushite, or whewellite-brushite-struvite). Scans were performed using dual-source CT in a dual-energy mode with the tubes simultaneously operating at 80 and 140 kV. Two readers analysed the data with respect to stone attenuation at each energy level. The stones were classified as UA- or non-UA-containing using manual attenuation measurements and software analysis results. Sensitivity, specificity, PPV, and NPV were calculated using crystallographic stone analysis as the gold standard. Twenty-six out of 40 stones (65%) contained no UA; 14 stones (35%) contained UA. When compared with UA-containing stones, the differences in attenuation values at 80 and 140 kV were significantly (P<0.001) higher in stones containing no UA. The software automatically mapped 39/40 stones (98%). Only one (2%) 2 mm UA-stone was missed. The software correctly classified all detected stones as UA- or non-UA-containing. The attenuation values of the missed stone were manually plotted into the analysis sheet which allowed for the correct classification of the stone (containing UA). Therefore, the sensitivity, specificity, PPV, and NPV for the detection of UA-containing stones was 100%. Ex vivo experience indicates that differentiation between UA- and non-UA-containing stones can be accurately performed using dual-source dual-energy CT.