Multidetector Computed Tomography System Research Articles

Computed Tomography Enteroclysis in the Diagnosis of Intestinal Diseases

The role of computed tomography (CT) enteroclysis in the imaging of small bowel diseases is expanded with recent technological advances in multidetector CT system. Computed tomography enteroclysis is the examination of choice for patients with symptoms of intermittent small bowel obstruction, especially when there is a history of prior complex abdominal surgery, abdominal tumor, radiation therapy, and also in high grade obstructions with suspicion of extraintestinal internal fistula. Computed tomography enteroclysis is becoming the first-line modality for the evaluation of advanced and complicated small bowel Crohn disease. Computed tomography enteroclysis can also become an important complementary imaging technique to capsule endoscopy in the assessment of small bowel neoplasms and occult gastrointestinal hemorrhage. In this study, the technique and clinical applications of CT enteroclysis are reviewed; its advantages and limitations compared with the other imaging techniques and capsule endoscopy are discussed.

64 slice MDCT generally underestimates coronary calcium scores as compared to EBT: A phantom study

The objective of our study was the determination of the influence of the sequential and spiral acquisition modes on the concordance and deviation of the calcium score on 64-slice multi-detector computed tomography (MDCT) scanners in comparison to electron beam tomography (EBT) as the gold standard. Our methods and materials were an anthropomorphic cardio CT phantom with different calcium inserts scanned in sequential and spiral acquisition modes on three identical 64-slice MDCT scanners of manufacturer A and on three identical 64-slice MDCT scanners of manufacturer B and on an EBT system. Every scan was repeated 30 times with and 15 times without a small random variation in the phantom position for both sequential and spiral modes. Significant differences were observed between EBT and 64-slice MDCT data for all inserts, both acquisition modes, and both manufacturers of MDCT systems. High regression coefficients (0.90-0.98) were found between the EBT and 64-slice MDCT data for both scoring methods and both systems with high correlation coefficients (R2>0.94). System A showed more significant differences between spiral and sequential mode than system B. Almost no differences were observed in scanners of the same manufacturer for the Agatston score and no differences for the Volume score. The deviations of the Agatston and Volume scores showed regression dependencies approximately equal to the square root of the absolute score. The Agatston and Volume scores obtained with 64-slice MDCT imaging are highly correlated with EBT-obtained scores but are significantly underestimated (-10% to -2%) for both sequential and spiral acquisition modes. System B is more independent of acquisition mode to calcium score than system A. The Volume score shows no intramanufacturer dependency and its use is advocated versus the Agatston score. Using the same cut points for MDCT-based calcium scores as for EBT-based calcium scores can result in classifying individuals into a too low risk category. System information and scanprotocol is therefore needed for every calcium score procedure to ensure a correct clinical interpretation of the obtained calcium score results.

The Emerging Role of 64-Slice Multidetector Computed Tomography (MDCT) Coronary Angiography in Risk Stratification of Patients with Low (

Background: Patients with low calcium scores (CS) considered to be at low risk for cardiac events are often reassured, and not usually considered for lipid lowering therapy. A low CS, however, does not preclude the finding of non-calcified plaque (NCP) and even ischaemia. The earlier detection of NCP by newer generation MDCT systems may play an increasing role in more accurately determining true cardiac risk by providing a more reliable estimation of overall plaque burden beyond the mere assessment of calcium.

Cardiac Computed Tomography: Is It Ready For Primetime?

INTRODUCTION The last decade has witnessed dramatic improvements in computed tomography (CT) technology with the development of both electron beam (EB) and multi-detector (MD ) CT systems. EBCT provided the first attempt at high-resolution “freeze frame” images of the heart and coronary arteries, with 50 msec image acquisition times obviating distortion and blurring of the continuously moving myocardium. Developments in MDC T have included increasing gantry speeds to improve temporal resolution and the addition of multiple detector arrays that allow submillimeter spatial resolution and reduced image acquisition times. Although EBCT has higher temporal resolution than MDCT and lower radiation exposure through prospective triggering of the X-ray beam at a specific time in the cardiac cycle, MDCT provides higher spatial resolution and is generally more accessible to the medical community. Both techniques can be used to assess cardiac structure, determine the presence and extent of coronary artery calcificati...

Diagnostic accuracy of multidetector computed tomography coronary angiography in patients with angiographically proven coronary artery disease

ObjectivesThe aim of the present study was to evaluate the diagnostic accuracy in detecting high-grade coronary stenoses in patients with known coronary artery disease (CAD) using multidetector computed tomography (MDCT). BackgroundThe MDCT systems with electrocardiographic (ECG)-gating permit visualization of the coronary arteries. However, severe calcifications and higher heart rates are known to degrade image quality and limit correct diagnosis. MethodsSixty-six patients with proven CAD as assessed by conventional coronary angiography (CCA) were studied by MDCT (mean time 24 months postangiography). Total calcium score and all coronary arteries, including distal segments and side branches, were assessed with respect to evaluability, presence of high-grade coronary artery stenoses (>70%), and correct diagnosis. Results were compared to CCA. ResultsA total of 105 lesions were detected by CCA. The MDCT correctly detected 39 lesions (sensitivity 37%, specificity 99%). The correct clinical diagnosis could be obtained in 24 patients (36%). Artifacts due to elevated heart rates or severe coronary artery calcification were the main cause of degraded image quality inhibiting correct diagnosis. In 21/66 patients (32%) all four major coronary vessel segments could be visualized. A threshold for maximum heart rate and a maximum calcification level were established (65 beats/min and an Agatston Score Equivalent of 335, respectively). A second analysis was made using these thresholds. Of all patients studied, 10/11 (91%) were correctly diagnosed when adhering to these thresholds. ConclusionsWhen using MDCT as a noninvasive diagnostic modality to assess advanced CAD, it appears to be mandatory to preselect patients in order to achieve reliable results.

Computed tomography angiography: principles and clinical applications.

Clinical applications of computed tomography (CT) angiography have increased with the improved technology of multidetector CT systems. Adequate contrast enhancement and the timing of image acquisition are key elements in producing technically adequate CT angiograms. This review article provides guidelines and protocols for four-, eight- and 16-channel multidetector systems in studies of the thoracoabdominal aorta, aortoiliac, and abdominal visceral vasculature, abdominal and extremity run-off studies, and carotid/cerebral CT angiography.