Pericardial sinuses and recesses: findings at electrocardiographically triggered electron-beam CT.

PURPOSE: To evaluate the appearance of the pericardial sinuses and recesses at electrocardiographically triggered electron-beam computed tomography (CT). MATERIALS AND METHODS: Findings in 100 patients without known pericardial disease were reviewed. The patients underwent electron-beam CT of the heart because of suspected coronary arterial disease. Incremental electrocardiographically triggered images were obtained with a 100-msec exposure time and 1.5-mm section thickness after intravenous administration of contrast material. The appearance of the pericardial sinuses and recesses was determined. RESULTS: In each patient, at least one of the sinuses was visible at CT. The transverse and oblique sinuses (or one of their recesses) were depicted in 95 and 89 patients, respectively. The left pulmonic recess was depicted in 81 patients; inferior aortic recess, 80 patients; posterior pericardial recess, 67 patients; left pulmonic vein recess, 60 patients; right pulmonic recess, 51 patients; superior aortic recess, 47 patients; right pulmonic vein recess, 29 patients; and postcaval recess, 23 patients. CONCLUSION: Pericardial sinuses and recesses are frequently depicted on electrocardiographically triggered electron-beam CT images. Knowledge of their locations is helpful in the differentiation of normal pericardium from pericardial effusions and mediastinal processes such as lymph nodes.     

Evaluation of left and right ventricular diastolic function by electron-beam computed tomography in patients with passive epicardial constraint

OBJECTIVE: Previous investigations have shown the usefulness of electron-beam computed tomography (EBCT) to describe ventricular diastolic function and to detect constrictive filling pattern. We used EBCT to analyze diastolic function in patients who underwent passive epicardial constraint because data describing ventricular filling in these patients are still incomplete. METHODS: Ten patients with dilated cardiomyopathy (group 1) underwent EBCT examination before and again 6 months after surgery. Ten patients with normal diastolic function (group 2) and 5 male patients with constrictive pericarditis (group 3) served for comparison. Volume-time curves throughout the entire diastole were generated, and the rapidity of diastolic filling was assessed by calculating the percent filling fraction at consecutive EBCT frames throughout the diastole. Pericardial thickness was measured in a standardized fashion at different locations around both ventricles. RESULTS: Early left ventricular filling pattern in group 1 did not change postoperatively (filling fraction at third diastolic frame was 50.0 +/- 15.4% and 53.8 +/- 14.4% before and after surgery, respectively) and was not significantly different from group 2 (48.7 +/- 8.5%). In contrast, in group 3, early left ventricular filling was significantly accelerated (71.4 +/- 9.3%) when compared with groups 1 and 2. A similar pattern was observed for the right ventricle. Pericardial thickness between groups 1 (1.22 +/- 4.22 and 1.43 +/- 0.39 mm before and after surgery, respectively) and 2 (1.38 +/- 0.43 mm) did not differ significantly. In contrast, pericardium in group 3 was significantly thickened (4.93 +/- 1.11 mm) when compared with both groups 1 and 2. CONCLUSIONS: The EBCT identified an abnormal accelerated diastolic filling and thickened pericardium in patients with constrictive pericarditis. Conversely, a normal diastolic filling pattern and pericardial thickness seem to be preserved in patients after passive epicardial constraint, when compared with baseline values and with normal subjects.     

Rapid-acquisition computed tomography demonstration of chronic calcified pericardial constriction

Dynamic imaging by a new ultrafast computed tomography scanner of a patient with chronic calcified pericardial constriction is presented. Images of the heart throughout the cardiac cycle demonstrate compression of the right ventricle by calcified pericardium. Hemodynamic data was derived from the scan study to support the diagnosis of pericardial constriction, which was confirmed on cardiac catheterization.     

Coronary calcium measurements: effect of CT scanner type and calcium measure on rescan reproducibility--MESA study

PURPOSE: To evaluate the effect of scanner type and calcium measure on the reproducibility of calcium measurements. MATERIALS AND METHODS: This investigation was approved by the institutional review boards of each study site and by the Institutional Review Board of the Los Angeles Biomedical Research Institute. Informed consent for scanning and participation was obtained from all participants. The study was Health Insurance Portability and Accountability Act compliant. The Multi-Ethnic Study of Atherosclerosis (MESA) is a multicenter observational study of 6814 participants undergoing demographic, risk factor, and subclinical disease evaluations. Coronary artery calcium was measured by using duplicate CT scans. Three study centers used electron-beam computed tomography (CT), and three used multi-detector row CT. Coronary artery calcium was detected in 3355 participants. Three calcium measurement methods-Agatston score, calcium volume, and interpolated volume score-were evaluated. Mean absolute differences between calcium measures on scans 1 and 2, excluding cases for which both scans had a measure of zero, was modeled by using linear regression to compare reproducibility between scanner types. A repeated measures analysis of variance test was used to compare reproducibility across calcium measures, with mean percentage absolute difference as the outcome measure. Rescan reproducibility in relation to misregistrations, noise, and motion artifacts was also examined. Variables were log transformed to create a more normal distribution. RESULTS: Concordance for presence of calcium between duplicate scans was high and similar for both electron-beam and multi-detector row CT (96%, kappa = 0.92). Mean absolute difference between calcium scores for the two scans was 15.8 for electron-beam and 16.9 for multi-detector row CT scanners (P = .06). Mean relative differences were 20.1 for Agatston score, 18.3 for calcium volume, and 18.3 for interpolated volume score (P < .01). Reproducibility was lower for scans with versus those without image misregistrations or motion artifacts (P < .01 for both). CONCLUSION: Electron-beam and multi-detector row CT scanners have equivalent reproducibility for measuring coronary artery calcium. Calcium volumes and interpolated volume scores are slightly more reproducible than Agatston scores. Reproducibility is lower for scans with misregistrations or motion artifacts.     

Symptomatic pericardial constriction without active pericarditis

The decision to undergo pericardectomy for symptomatic pericardial constriction is usually dictated by an image of an abnormal pericardium. We report a case of symptomatic pericardial constriction despite radiographic and pathological evidence of a normal pericardium. The patient was successfully treated with a pericardectomy, with resolution of constrictive hemodynamics and symptoms. Our report suggests that a normal pericardium by computed tomography and biopsy should not preclude pericardectomy for patients who have refractory symptoms, physical findings, and intracardiac pressures diagnostic of constrictive pericarditis.     

Primary heart angiosarcoma detected by magnetic resonance imaging

We present a case of primary heart angiosarcoma in a 38-year-old male. The patient presented with severe dyspnoe and arrhythmia. Echocardiography showed multiple solid masses in the pericardium and pericardial effusion. Chest radiography revealed left-sided pleural effusion and suspicion of a mass projected on the right atrium. Non-enhanced chest computed tomography raised the suspicion of a pericardial neoplasm projected on the right atrium adjacent to ascending aorta with markedly thickened pericardium and multiple round-shaped masses around the heart. Cardiac-gated magnetic resonance imaging demonstrated an inhomogeneous mass in the free wall of the right atrium adjacent to ascending aorta and multiple pericardial masses. Biopsy performed through thoracoscopy confirmed the diagnosis of a primary heart angiosarcoma.     

Appearance of the Normal Pericardium on Coronary MR Angiograms

We evaluated the appearance of the normal pericardium on breath-hold MR images used to visualize coronary arteries. A coronary MR angiogram was obtained in 23 subjects (17 healthy volunteers and six patients with no known pericardia! disease) using a breath-hold K-space segmented gradient-recalled echo sequence with fat suppression. Each coronary MR angiographic study included imaging planes equivalent to the following echocardiographic planes: four-chamber view, vertical two-chamber view, and two short-axis views (at base and mid ventricular level). The average pericardial thickness was 1.7 mm (range, 1.5–2.0 mm), and an average length of 60 mm (range, 20–110 mm) of pericardium was visualized. A significantly longer portion of the pericardium was seen in the vertical two-chamber view and the basal short-axis view than in the two other views (P <.001). Normal anatomic variations and overlapping structures and image artifacts can alter the appearance of the pericardium. Breath-hold MR imaging techniques used for coronary MR angiography allow routine, time-efficient evaluation of large portions of the pericardium.     

Simple single-section method for measurement of left and right atrial volumes with electron-beam CT

RATIONALE AND OBJECTIVES: The authors estimated left and right atrial volumes by using a simple method of measurement with nonenhanced electron-beam computed tomography (CT). MATERIALS AND METHODS: One hundred sixty-four contrast material-enhanced electron-beam CT studies were divided into two groups. Group 1, which included 104 studies, was used to develop the measurement method (i.e., the formulas) for measuring left and right atrial volumes from a nonenhanced study. Group 2 consisted of 60 studies on which the validity of the method was tested. Measurement of left and right atrial volumes was performed on all section levels by tracing the respective atrial borders for each section, then multiplying the area by section thickness and summing the resultant volumes. RESULTS: Calculated left and right atrial volumes were derived by using the biggest atrial area and cephalic-caudal span. The span was equal to section thickness times the number of sections in which the atria were present. Linear regression analysis formulas were acquired with the biggest atrial area and cephalic-caudal span. Left and right atrial calculated volumes were obtained with these formulas and demonstrated a significant good relation (r > .95, P < .001) and a difference of less than 11% (P < .05) in absolute values between measured and calculated volumes. Intraobserver, interobserver, and interstudy reproducibility were excellent, with less than 10% difference in absolute values. CONCLUSION: Left and right atrial volumes can be accurately estimated from a single midventricular section by using nonenhanced electron-beam CT.     

Computed tomography and magnetic resonance imaging of the pericardium: anatomy and pathology.

The purpose of this article is to review the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI) of the pericardium and pericardial diseases. Because patients with pericardial diseases usually present with nonspecific symptoms, these diseases may not be detected until they have reached an advanced stage. It is therefore important to distinguish between normal pericardial structure and disease. Multiplanar reconstruction images of CT and MRI are useful for evaluating faint changes of the pericardium. The specific pericardial diseases described in this article include pericardial cyst, constrictive pericarditis, pericarditis with radiation pericarditis, postoperative pericardial hematoma, and cardiac tamponade due to a paracardiac mass (lymphoma).     

In-plane coronary arterial motion velocity: measurement with electron-beam CT

PURPOSE: To determine the speed of and changes in the speed of coronary arterial movement during the cardiac cycle with electron-beam computed tomography (CT). MATERIALS AND METHODS: With electron-beam CT, 20 consecutive cross-sectional images were acquired at the mid right coronary artery (with 50-msec acquisition time, 8-msec intersection delay, 7-mm section thickness, and intravenous administration of 40 mL of contrast agent) in 25 patients. On the basis of the displacement of the left anterior descending, left circumflex, and right coronary arterial cross sections from image to image, movement velocity in the transverse imaging plane was calculated and was correlated with the simultaneously recorded electrocardiogram. RESULTS: The velocity of in-plane coronary arterial motion varied considerably during the cardiac cycle. Peaks were caused by ventricular systole and diastole and by atrial contraction. The mean velocity was 46.6 mm/sec +/- 12. 5 (SD). The mean velocity of right coronary arterial movement (69.5 mm/sec +/- 22.5) was significantly faster than that of the left anterior descending (22.4 mm/sec +/- 4.1) or the left circumflex coronary artery (48.4 mm/sec +/- 15.0). The lowest mean velocity (27. 9 mm/sec) was at 48% of the cardiac cycle. CONCLUSION: The lowest velocity of coronary arterial movement, which displays considerable temporal variation, was at 48% of the cardiac cycle.     

Quantitative parameters of image quality in 64-slice computed tomography angiography of the coronary arteries

We explored quantitative parameters of image quality in consecutive patients undergoing 64-slice multi-detector computed tomography (MDCT) coronary angiography for clinical reasons. Forty-two patients (36 men, mean age 61 +/- 11 years, mean heart rate 63 +/- 10 bpm) underwent contrast-enhanced MDCT coronary angiography with a 64-slice scanner (Siemens Sensation 64, 64 mm x 0.6 mm collimation, 330 ms tube rotation, 850 mAs, 120 kV). Two independent observers measured the overall visualized vessel length and the length of the coronary arteries visualized without motion artifacts in curved multiplanar reformatted images. Contrast-to-noise ratio was measured in the proximal and distal segments of the coronary arteries. The mean length of visualized coronary arteries was: left main 12 +/- 6 mm, left anterior descending 149 +/- 25 mm, left circumflex 89 +/- 30 mm, and right coronary artery 161 +/- 38 mm. On average, 97 +/- 5% of the total visualized vessel length was depicted without motion artifacts (left main 100 +/- 0%, left anterior descending 97 +/- 6%, left circumflex 98 +/- 5%, and right coronary artery 95 +/- 6%). In 27 patients with a heart rate < or = 65 bpm, 98 +/- 4% of the overall visualized vessel length was imaged without motion artifacts, whereas 96+/-6% of the overall visualized vessel length was imaged without motion artifacts in 15 patients with a heart rate > 65 bpm (p < 0.001). The mean contrast-to-noise ratio in all measured coronary arteries was 14.6 +/- 4.7 (proximal coronary segments: range 15.1 +/- 4.4 to 16.1 +/- 5.0, distal coronary segments: range 11.4 +/- 4.2 to 15.9 +/- 4.9). In conclusion, 64-slice MDCT permits reliable visualization of the coronary arteries with minimal motion artifacts and high CNR in consecutive patients referred for non-invasive MDCT coronary angiography. Low heart rate is an important prerequisite for excellent image quality.     

Motion artifacts in subsecond conventional CT and electron-beam CT: pictorial demonstration of temporal resolution.

To visually demonstrate the effective temporal resolution of subsecond conventional (slip-ring) and electron-beam computed tomographic (CT) systems, two phantoms containing high-contrast test objects were scanned with a slip-ring CT system (effective exposure time, 0.5 second) and an electron-beam CT system (exposure time, 0.1 second). Images were acquired of each phantom at rest, during translation along the x axis at speeds of 10-100 mm/sec, and during rotation about isocenter at speeds of 0.1 and 0.5 revolution per second. Motion artifacts and loss of spatial resolution were judged to be absent, noticeable, or severe. For 0.5-second conventional CT images, motion artifacts and loss of spatial resolution were noticeable at 10 mm/sec and 0.1 revolution per second and were severe at speeds greater than or equal to 20 mm/sec and at 0.5 revolution per second. For 0.1-second electron-beam CT scans, noticeable, but not severe, motion artifacts and loss of spatial resolution occurred at speeds between 40 and 100 mm/sec and at 0.5 revolution per second. Over the range of physiologic speeds examined, the images provide visually compelling evidence of the effect of improving temporal resolution in CT.     

Computed tomography and magnetic resonance imaging of the pericardium

Computed tomography is an established modality for the evaluation of the pericardium. It is used to evaluate complicated pericardial effusions, pericardial thickening, calcific pericarditis, pericardial cysts, postoperative changes and primary and metastatic neoplasms of the pericardium. Magnetic resonance imaging is being used with increasing frequency in the evaluation of pericardial disease. It offers advantages over computed tomography, including a potential for tissue characterization, absence of ionizing radiation or need for intravenous contrast medium, and the ability to scan in any plane. Disadvantages include greater cost, longer examination times and the inability to identify calcification positively.     

How to differentiate benign versus malignant cardiac and paracardiac 18F FDG uptake at oncologic PET/CT

Patients undergoing 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) whole-body oncologic positron emission tomography (PET)/computed tomography (CT) are studied while fasting. Cardiac FDG uptake in fasted patients has been widely reported as variable. It is important to understand the normal patterns of cardiac FDG activity that can be seen in oncologic FDG PET/CT studies. These include focal and regional patterns of increased FDG myocardial activity. Focal activity can be observed in papillary muscles, the atria, the base, and the distal anteroapical region of the left ventricle. Regional increased cardiac FDG activity may be diffuse or localized in the posterolateral wall or the base of the left ventricle. Abnormal patterns of cardiac FDG activity not related to malignancy include those associated with lipomatous hypertrophy of the interatrial septum, epicardial and pericardial fat, increased atrial activity associated with atrial fibrillation or a prominent crista terminalis, cardiac sarcoidosis, endocarditis, myocarditis, and pericarditis. Knowledge of these patterns of cardiac FDG activity is important to be able to recognize malignant disease involving the paracardiac spaces, myocardium, and pericardium. With a better understanding of the range of normal and abnormal patterns of cardiac FDG activity, important benign and malignant diseases involving the heart and pericardium can be recognized and diagnosed.     

Optimal electrocardiographically triggered phase for reducing motion artifact at electron-beam CT in the coronary artery

RATIONALE AND OBJECTIVES: The authors performed this study to (a) investigate coronary movement with electron-beam computed tomography (CT) and (b) find the optimal electrocardiographic (ECG) triggering phase for eliminating motion artifact. MATERIALS AND METHODS: One hundred fifty-one patients without arrhythmia were examined with electron-beam CT. First, movie scans were obtained to create displacement and velocity graphs of coronary artery movement. Then, a volume scan with an exposure time of 100 msec was obtained with various ECG trigger settings. RESULTS: Movement patterns of coronary arteries varied with heart rate. Optimal triggering phase was before atrial systole (near 71% of the R-R interval) when heart rate was slower than 68 beats per minute and at ventricular end systole when heart rate was fast. Rate of severe motion artifacts decreased from 43% to 0% when triggering was altered from 80% of the R-R interval to the individual optimal value. Experimental values of the optimal phase at different heart rates were derived, and severe motion artifact was only 3.0% with these values. CONCLUSION: ECG triggering set according to the heart rate enables a great reduction in motion artifacts at electron-beam CT with a 100-msec exposure time. The results may have implications for magnetic resonance imaging of the coronary artery.     

Computed tomography of cardiac and pericardial tumors

Computed tomography (CT) scans in 30 patients with neoplastic involvement of the heart and pericardium were retrospectively reviewed. Computed tomography was compared with echocardiography in three of four patients with large primary cardiac tumors and in three patients with metastatic pericardial disease. Computed tomography was superior to echocardiography in determining tumor extent and site of origin of a right atrial sarcoma, as well as in assessing tumor extent and presence of pulmonary arterial hypertension in a left atrial malignant fibrous histiocytoma and a left atrial myxoma. Pericardial effusions were detected by echocardiography in two out of three patients with metastatic pericardial disease, but the malignant nature of the effusion was not recognized; in all three cases CT showed nodular pericardial thickening. Of the 23 patients with evidence on CT of direct extension of anterior mediastinal masses, bronchogenic carcinoma or mesothelioma to the pericardium 21 had nodular pericardial thickening and 2 diffuse thickening; only 6 had pericardial effusion. We conclude that CT is useful in the characterization of large primary cardiac tumors that are incompletely visualized with echocardiography. Computed tomography is superior to echocardiography in assessing tumor involvement of the pericardium because pericardial effusions are often absent; CT is also superior in identifying nodular pericardial thickening.     

Imaging the pericardium: appearances on ECG-gated 64-detector row cardiac computed tomography

Multidetector row computed tomography (MDCT) with its high spatial and temporal resolution has now become an established and complementary method for cardiac imaging. It can now be used reliably to exclude significant coronary artery disease and delineate complex coronary artery anomalies, and has become a valuable problem-solving tool. Our experience with MDCT imaging suggests that it is clinically useful for imaging the pericardium. It is important to be aware of the normal anatomy of the pericardium and not mistake normal variations for pathology. The pericardial recesses are visible in up to 44% of non-electrocardiogram (ECG)-gated MDCT images. Abnormalities of the pericardium can now be identified with increasing certainty on 64-detector row CT; they may be the key to diagnosis and therefore must not be overlooked. This educational review of the pericardium will cover different imaging techniques, with a significant emphasis on MDCT. We have a large research and clinical experience of ECG-gated cardiac CT and will demonstrate examples of pericardial recesses, their variations and a wide variety of pericardial abnormalities and systemic conditions affecting the pericardium. We give a brief relevant background of the conditions and reinforce the key imaging features. We aim to provide a pictorial demonstration of the wide variety of abnormalities of the pericardium and the pitfalls in the diagnosis of pericardial disease.The rapid technological development of multidetector row computed tomography (MDCT) with its greatly improved spatial and temporal resolution and sophisticated ECG-gated image acquisition software has led to the more widespread use of dedicated cardiac imaging. Not only does this technology enable assessment of the coronary arteries [1, 2], but the same acquired data set also provides imaging detail of the overall cardiac morphology including the normal and diseased pericardium, features of which may also be readily appreciated on the non-ECG-gated thoracic CT [3]. It is important for the general radiologist to be familiar with both normal and variant pericardial anatomy and with that of the pericardial recesses, which can mimic some pathological processes. Several disease processes, either primary or secondary, can affect the pericardium. This review aims to illustrate normal pericardial anatomy, diagnostic pitfalls, commonly encountered abnormalities (some of which may be quite subtle) and some more unusual entities.     

Pericardium – Radiological diagnostics

Summary Evaluation of the pericardium using the capabilities of computed tomography (CT) and magnetic resonance imaging (MRI) remains one of the last requests to the radiologists within the spectrum of cardiac diagnostics. New technical developments in CT and MRI improve diagnostic acuracy in diagnosing pericardial disease and help to define adequate therapeutic management. The purpose of this article is to review the diagnostic possibilities of the radiologist in pericardial diseases with emphasis on CT and MRI. The anatomy of the normal pericardium including pericardial recessus and sinuses is reviewed followed by a brief discussion of congenital abnormalities. Particular attention is paid to acquired pericardial diseases including the potential characterization of pericardial effusions. Pericardial thickening and pericardial constrictions are discussed and the differentiation between pericardial constriction and restrictive cardiomyopathy is highlighted because of the therapeutic implications. Finally a brief review of primary and metastatic pericardial tumours is given. Eingegangen am 30. Januar 1997 Angenommen am 5. Februar 1997     

Effect of motion on cardiac SPECT imaging: Recognition and motion correction

Cardiac motion is likely to occur during long single photon emission computed tomography acquisitions or if there is considerable patient discomfort. Motion causes data misregistration and may decrease the accuracy of interpretation of cardiac single photon emission computed tomography by introducing image artifacts, such as smearing of counts around the ventricle ("hurricane sign"), distortion and discontinuities of the ventricular walls, nonanatomic defects, and hot spots. Although motion should be avoided during data acquisition, motion correction techniques have been developed to allow for manual or semiautomated compensation of cardiac displacement and should be used when motion cannot be eliminated.     

Motion artifacts on coronary CT angiography images in patients with a pericardial effusion

BackgroundPatients with a pericardial effusion can have a pendulum-like movement of the heart. No reports associate the presence of pericardial fluid with coronary CT angiography (CTA) images that are degraded by motion artifact.ObjectiveWe tested the hypothesis that patients with pericardial effusion have coronary CTA images compromised by motion artifacts, even when other known causes of motion artifact in coronary imaging are minimized.MethodsAmong the prospectively electrocardiogram-gated single heart beat 320-detector row coronary CTA studies performed from September 2009 to May 2013, 13 consecutive studies acquired with a heart rate <60 beats/min that indicate a pericardial effusion formed an effusion cohort. A control cohort included 13 studies with no pericardial fluid performed by the same CT scanner; these were pair-matched to the effusion cohort for heart rate, sex, age, and body mass index. All studies were free of arrhythmia and respiratory motion. Motion artifact was separately assessed (3-point scale) at 8 coronary segments by 2 cardiovascular imaging teams.ResultsThe mean pericardial effusion volume for the effusion cohort was 129 ± 57 mL (range, 39–222 mL). Intra-observer/interobserver reproducibility of the motion artifact scores were good (κ = 0.636–0.791). Motion artifacts were more frequently observed in the effusion cohort for the left circumflex (no, mild, severe artifact, 54%, 46%, 0% vs 81%, 19%, 0%, respectively, for effusion vs control; P = .039) and right coronary arteries (no, mild, severe artifact = 41%, 44% 15% vs 79%, 21%, 0%, respectively, for effusion vs control; P < .001), especially for the middle or distal segments. Larger effusion volumes were associated with more severe motion artifacts.ConclusionPatients with pericardial effusion have coronary CTA images compromised by cardiac motion artifacts, particularly in the left circumflex and right coronary arteries.