Multislice computed tomography cardiac imaging: current status

Usefulness of helical computed tomography in detection of mitral annular calcification as a marker of coronary artery disease

BACKGROUND

Mitral annulus calcification (MAC) may be a form of atherosclerosis. The goal of the present work was to investigate whether helical CT can determine the presence of MAC and to clarify its possible association with coronary artery disease (CAD) in elderly patients.

DESIGN AND METHODS

Three hundred and twenty-nine consecutive elderly patients (165 men and 164 women, age range 60-79 years) underwent double helical CT of the heart to determine MAC and coronary calcifications (CC) according to a previously described protocol.

RESULTS

MAC was documented in 60 patients (25 men, 35 women; mean age 69 +/- 4.5 years, range 60-78 years). The non-MAC group (control) included 269 patients (140 men, 129 women; mean age 67 +/- 4.6 years, range 60-79 years). Age was the only risk factor which had significant association with MAC (p = 0.01). A significant difference was found between MAC and control group for mean total CC score and advanced CC (total CC > 300) (323 +/- 565 vs. 184 +/- 429, p = 0.033 and 30% vs. 16%, p = 0.017, respectively). A significant difference was also found between groups for the prevalent proven CAD (30% vs. 16%, p = 0.008). Stepwise logistic regression analysis identified age [odds ratio (OR) 3.3, 95% confidence interval (CI) 1.7-6.4, p < 0.001)], gender (male) (OR 3.1, 95% CI 1.6-6.0, p = 0.001), and MAC (OR 2.4, 95% CI 1.2-5.0, p = 0.016) as the independent variables significantly associated with CAD. The independent variables significantly associated with advanced CC (TCS > 300) were MAC (OR 2.6, 95% CI 1.3-5.2, p = 0.005), gender (male) (OR 2.3, 95% CI 1.2-4.2, p = 0.012) and age (OR 1.9, 95% CI 1.0-3.7, p = 0.052).

CONCLUSIONS

Our study demonstrated the usefulness of helical computed tomography in the detection of mitral annular calcification as an additional marker of prevalent CAD. However, the diagnostic significance of the MAC detection is relatively minor and should not be considered as a direct proof for coronary atherosclerosis.

Myocardial infarction on non-ECG synchronized contrast-enhanced multi-detector computed tomography

To demonstrate that myocardial infarctions can be visualized on non-ECG-synchronized, contrast-enhanced multidetector computed tomography (MDCT). Myocardial infarctions are visible on contrast-enhanced MDCT scans even when cardiac gating is not utilized. Focusing on myocardial enhancement should allow radiologists to play a greater role in the evaluation of cardiac disease.

MDCT Evaluation of the Coronary Arteries, 2004: How We Do It—Data Acquisition, Postprocessing, Display, and Interpretation

OBJECTIVE

Cardiac CT is rapidly becoming part of clinical practice. The objective of this article is to discuss and illustrate the current practice of coronary artery MDCT, including data acquisition, postprocessing, image display, and interpretation. The practice described reflects our experience with a series of patients referred in routine clinical practice.

CONCLUSION

The reader should gain an insight into the current clinical application of coronary artery CT.

Evaluation of Venous and Arterial Conduit Patency by 16-Slice Spiral Computed Tomography

Background— Computed tomography has been shown to be useful in the evaluation of aortocoronary bypass grafts (CABG). This is the first prospective study to evaluate the accuracy of a new-generation scanner in the detection of patency and significant stenoses (>50% decrease in diameter) of venous and arterial grafts in patients with previous CABG.

Methods and Results— In 96 patients (80 males, mean age 62 years) with previous CABG, a multislice computed tomography (MSCT) scan was performed (collimation 16×0.625 mm). Patients with atrial fibrillation, renal failure, severe respiratory disease, severe heart failure, heart rate >70 bpm despite therapy, or unstable angina were excluded. A total of 285 conduits implanted on the native coronary arteries at the time of CABG were evaluated. MSCT data were analyzed by 2 independent radiologists and compared with the results of conventional angiography. Three patients were excluded from analysis. All conduits were judged evaluable in 84 patients. Among these patients, MSCT correctly diagnosed 54 occluded grafts and 4 significant stenoses on the body of the grafts. Of the 17 significant anastomotic lesions, MSCT correctly diagnosed 15. For these 84 patients, diagnostic accuracy was 99%, sensitivity was 97%, and specificity was 100%. When all 93 patients were considered, the sensitivity of MSCT in diagnosing significant stenoses was 96%.

Conclusions— MSCT with the new-generation scanner allows for accurate assessment of venous and arterial conduits in patients with previous CABG with a high degree of sensitivity and specificity. Exclusion criteria and radiation exposure remain limitations of the method.

[Pericardium and cardiac valves: value of MRI and Multislice CT]

Color Doppler echocardiography has limitations, particularly in the assessment of valvular regurgitation and pericardial diseases. MRI, with the help of three dimensional morphologic data, dynamic acquisitions with cine techniques and functional evaluation with flow sensitive techniques can be envisioned as a complementary noninvasive procedure able to provide the complete information required for planning therapeutic options. Qualitative as well as accurate and reproducible quantitative information (volume measurements, cardiac function and flow velocity profiles) are unique for the evaluation of the severity of valve or pericardial diseases. Multislice CT is unique in precisely demonstrating valvular and pericardial calcifications. This article reviews both imaging techniques used in assessing valvular and pericardial disease and discusses the advantages and limitations of these techniques in current clinical applications.

Imagerie non invasive des artères coronaires : TDM et IRM

The advent of helical multidetector CT has significantly modified several traditional clinical approaches to cardiovascular diagnosis. The current availability of rapid image acquisition has provided the basis for investigating direct imaging in real time of cardiac structures using CT. Application of thin-section submillimetric image acquisitions to three-dimensional (3D) reconstruction algorithms produces 3D data sets from which images of the coronary arteries may be obtained in any anatomic plane. The advantage of the submillimetric isotropic spatial resolution is partly offset by reduced temporal resolution as well as reduced contrast resolution compared to MRI. This lack in contrast sensitivity prevents accurate perfusion imaging and restricts the clinical use to coronary artery imaging. Moreover, the large amount of iodinated contrast medium injected has potential nephrotoxic effects, which can be deleterious if coronary artery angiography must to be performed. On the other hand, MRI has less spatial resolution, and acquisitions must be performed in the plane of each coronary artery because of reduced volume coverage. Both techniques play a role in the non-invasive assessment of coronary artery disease, by providing complementary information already useful in a growing number of clinical situations.

Current concepts in multi-detector row CT evaluation of the coronary arteries: principles, techniques, and anatomy

Cardiac imaging is becoming a practical application of mechanical computed tomography (CT) with the availability of four, eight, and 16 detector row scanners. The role of imaging is progressing from simple determination of the presence of arterial calcifications on nonenhanced scans to demonstration of vascular stenoses on coronary CT angiograms. Optimization of the imaging technique and knowledge of coronary artery anatomy are both important for the development of CT of the heart. Technical factors such as a slow heart rate, a short scanning time, subcentimeter spatial resolution, high temporal resolution, and reconstruction of multiple image data sets at various intervals in the cardiac cycle result in optimal visualization of the coronary arteries. Axial, thin-slab maximum intensity projection, and volume-rendered images are used to display the normal anatomy and anomalies of the coronary arteries. The challenges of CT angiography of the coronary arteries have been partially met and will likely be overcome with continued evolution of the technology.