When, Why, and How to Examine the Heart During Thoracic CT: Part 2, Clinical Applications

Detection of incidental cardiac findings in noncardiac chest computed tomography

The aim of the study was to estimate the rate of incidental cardiac findings (ICF) in patients undergoing noncardiac chest CT.An experienced radiologist retrospectively reviewed 237 consecutive patients (147 males and 90 females with median age of 69 years) undergoing a noncardiac chest CT. ICF at targeted review were compared to those mentioned in original reports (χ test).At review, ≥1 ICF was detected in 124/237 patients (52%), for a total of 229 ICF, 158 of them (69%) not originally mentioned. Valvular calcifications were unmentioned in 23/23 (100%) patients, main pulmonary artery dilation in 21/22 (96%), coronary calcifications in 69/86 (80%), right or left atrial dilation in 7/11 (64%), aortic atherosclerosis in 29/62 (47%), and ascending aorta dilatation in 8/18 (44%). All 6 pericardial effusions were originally mentioned. No association with sex (P ≥ .189); positive correlation with age (P < .001).Half of patients undergoing noncardiac chest CT presented ≥1 ICF, independently from sex but increasing with age. Moreover, 69% of detectable ICFs were not originally mentioned.

Every second counts: signs of a failing heart on thoracic CT in the ED

Impending cardiac failure is often difficult to recognize and requires a multidisciplinary approach. Upon arrival in the emergency department, patients are promptly screened for potentially life-threatening conditions through a history and physical examination. In many cases, the diagnosis is not clear until confirmatory laboratory or imaging tests are performed. Unfortunately, patients can rapidly decompensate as this diagnostic information is being obtained. Emergent CT plays a key role in identifying conditions that may result in cardiovascular collapse, including severe congestive heart failure, myocardial infarction, cardiac tamponade, and impending cardiac failure. Characteristic imaging findings can prompt the physician to take immediate action and prepare for resuscitation.

Detection of Cardiac Incidental Findings on Routine Chest CT: The Impact of Dedicated Training in Cardiac Imaging

PURPOSE

Routine chest CT and cardiac CT angiography (CTA) both image the heart, albeit with different precision and intent. The aim of this study was to evaluate the diagnostic ability of radiologists with different levels of cardiac training to identify cardiac findings on chest CT without electrocardiographic gating compared with a reference standard of electrocardiographically gated cardiac CTA.

METHODS

Electrocardiographically gated cardiac CT angiographic studies performed between January 2005 to January 2010 in patients with routine chest CT within six months were retrospectively identified. Fourteen radiologists at four stages of training (stage 1, residents with no cardiac training [n = 4]; stage 2, residents who had completed at least one dedicated rotation of cardiac imaging [n = 3]; stage 3, radiologists without cardiac training [n = 3]; and stage 4, radiologists with formal cardiac fellowship training [n = 4]) performed blinded, anonymized cardiac readings of chest CT images. Findings were categorized (coronary arterial, noncoronary vessel, cardiac chamber, myocardial, pericardial, and valve findings) with cardiac CTA as a reference standard.

RESULTS

Overall, 140 cardiac CT angiographic findings were reported in 63 of 77 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of nongated CTA were 43.6%, 96.8%, 83.0%, 81.6%, and 81.8%, respectively, for all readers. Increasing training was associated with higher sensitivity (30.3%, 35.7%, 45.7%, and 61.2% from stages 1 to 4) but similar specificity (96.4%, 96.7%, 96.3%, and 97.6% from stages 1 to 4). Frequently missed findings categories were coronary arterial, myocardial, and cardiac chamber findings.

CONCLUSIONS

Increasing cardiac imaging training correlates with increased sensitivity and stable specificity to detect cardiac findings on routine chest CT without electrocardiographic gating. Cardiac findings should be noted on chest CT when observed, and cardiac training should be encouraged.

Left atrio-vertebral ratio: A new computed-tomography measurement to identify left atrial dilation

BACKGROUND

Left cardiac chambers dilation, interstitial lung changes and pleural effusions are the characteristics of cardiogenic pulmonary oedema on computed tomography (CT) of the chest but mensuration of the left atrial size is not routinely performed. Cardiac chambers normal dimensions are known to be proportional to the patient's build and anthropomorphic data but adjustment of chambers dimensions to available elements seen on the axial CT images has never been evaluated before.

OBJECTIVES

Our objective was to use data easily available on axial images to directly scale the left atrium. We chose to divide the left atrial diameter by the thoracic vertebral diameter, using the latter as a body-mass indicator. As a preliminary study, we aimed to evaluate the range of values of this left atrio-vertebral ratio (LAVR) by comparing patients suffering from cardiogenic pulmonary oedema with patients free of cardiac disease. We hypothesized that if the difference of values in these two populations of patients was significant enough, this ratio would be relevant and could be used as a quick criterion in different clinical situations.

METHOD

Two radiologists reviewed CT scans of 32 of patients free of cardiac disease and 40 patients in acute cardiac failure. The maximum diameter of the left atrium at the level of the right inferior pulmonary vein was divided by the vertebral transverse diameter to generate a left atrio-vertebral ratio. Receiver operating characteristic curves identified the threshold associated with pulmonary oedema.

MEASUREMENTS AND MAIN RESULTS

The mean LAVR was 1.85 ± 0.27 in asymptomatic patients and 2.48 ± 0.35 in patients with pulmonary oedema. A LAVR of 2.1 yielded 85% sensitivity and 88% specificity for the diagnosis of cardiogenic pulmonary oedema.

CONCLUSIONS

LAVR is a simple new measure directly scaling the left atrial diameter to the anthropomorphic characteristics of the patient. In our series, a ratio above 2.1 is strongly associated with cardiogenic pulmonary oedema indirectly suggesting left atrial dilation. The results were significantly different between the two populations of patients (no heart condition versus cardiogenic pulmonary oedema) suggesting a high potential for clinical application.

Comprehensive CT cardiothoracic imaging: a new challenge for chest imaging

In the past, thoracic and cardiac imaging were two distinct specialties of radiology. The technical evolution, however, has changed their boundaries with an important impact on CT imaging practices and has opened the new era of "cardiothoracic" imaging, due to the strong anatomic, mechanical, physiologic, physiopathologic, and therapeutic cardiopulmonary correlations. Modern thoracic radiologists can no longer avoid the assessment of heart and coronary arteries, as they used to do with earlier generations of CT scanner. The advent of ECG gating and state-of-art CT scanner faster rotation speed, high spatial and temporal resolution, high-pitch mode, shorter acquisition time, and dedicated cardiac reconstruction algorithms has opened new possibilities for chest imaging, integrating cardiac morphologic and even functional information within a diagnostic chest CT scan. The aim of this review is to briefly show and summarize the concept of integrated cardiothoracic imaging, which redefines the boundaries of chest CT imaging, opening the door to a new radiologic specialty.

Approach to chest computed tomography

Computed tomography (CT) is central to the detection and diagnosis of a wide variety of pulmonary, cardiovascular, and other diseases of the chest. Successful interpretation of thoracic CT requires both an appreciation of the spectrum of normal appearances of the chest and a systematic approach to the characterization of thoracic pathology. This article provides an introduction to basic CT techniques and protocols, a review of normal CT anatomy, and an overview of commonly encountered abnormalities.

Imaging pulmonary arterial thromboembolism: challenges and opportunities

Magnetic resonance (MR) angiography of the pulmonary arteries is a rapidly evolving technique with proven clinical usefulness. Multiple-step protocols, such as MR perfusion followed by high-spatial resolution MR angiography, seem to be a good approach for the assessment of different vascular diseases affecting the pulmonary arteries. In combination with other imaging sequences, MR imaging is one of the most comprehensive potential noninvasive imaging techniques available.

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.

Morphological and functional imaging in COPD with CT and MRI: present and future

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. COPD is defined by irreversible airflow obstruction. It is a heterogeneous disease affecting the airways (i.e. chronic bronchitis, airway collapse), the parenchyma (i.e. hyperinflation, air trapping and emphysematous destruction) as well as the vasculature (i.e. hypoxic vasoconstriction, rarefication and pulmonary arterial hypertension) with different severity during the course of the disease. These different aspects of COPD can be best addressed by imaging using a combination of morphological and functional techniques. Three-dimensional high-resolution computed tomography (3D-HRCT) is the technique of choice for morphological imaging of the lung parenchyma and airways. This morphological information is to be accomplished by functional information about perfusion, regional lung mechanics, and ventilation mainly provided by MRI. The comprehensive diagnostic possibilities of CT complemented by MRI will allow for a more sensitive detection, phenotype-driven characterization and dedicated therapy monitoring of COPD as presented in this review.

Posttraumatic ventricular pseudoaneurysm in a 7-year-old child diagnosed with multidetector CT of the chest: a case report

We report the CT findings on a 7-year-old male who developed a left ventricular pseudoaneurysm involving the anterior septal left ventricular wall after blunt chest trauma.