Adaptive temporal resolution optimization in helical cardiac cone beam CT reconstruction

Abstract

Cone beam computed tomography scanners in combination with heart rate adaptive reconstruction schemes have the potential to enable cardiac volumetric computed tomography (CT) imaging for a larger number of patients and applications. In this publication, an adaptive scheme for the automatic and patient-specific reconstruction optimization is introduced to improve the temporal resolution and image quality. The optimization method permits the automatic determination of the required amount of gated helical cone beam projection data for the reconstruction volume. It furthermore allows one to optimize subvolume reconstruction yielding an increased temporal resolution. In addition, methods for the assessment of the temporal resolution are given which enable a quantitative documentation of the reconstruction improvements. Results are presented for patient data sets acquired in low pitch helical mode using a 16-slice cone beam CT system with parallel ECG recording.

Usefulness of Coronary Flow Reserve Measured by Echocardiography to Improve the Identification of Significant Left Anterior Descending Coronary Artery Stenosis Assessed by Multidetector Computed Tomography

“…Other scan parameters were adjusted according to the patient's body habitus (tube voltage 120 to 140 kVp, tube current 450 to 850 mAs). The spiral pitch (0.2 to 0.3) was adjusted according to the patient's heart rate, resulting in an average temporal resolution of 125 to 210 ms, using an adaptive multisegment reconstruction algorithm 14 and a gantry rotation time of 0.42 second. In 52 patients with a stable heart rate Ͻ60 beats/min at rest and no arrhythmia during scan preparation, electrocardiographically based dose modulation was implemented at a singlephase or dual phases according to the patient's heart rate.…”

“…Images were reconstructed at a thickness of 0.64 mm and a 180 to 220-mm field of view at several predetermined consistent physiologic phases of the cardiac cycle according to the heart rate. 14,15 The reconstructed axial slices were stacked in a volume to generate a 3-dimensional data set. In patients with a LAD stent, not only the stented tract, but also the entire coronary vessel was evaluated.…”

Significant Coronary Artery Disease in Patients with a Negative Calcium Scan and Suspicious Ischemic Heart Disease in a Racially Diverse Patient Population~!2009-10-05~!2010-01-26~!2010-06-08~!

“…Additional phases with 5% increments were reconstructed such as 70%-80%, if motion artifacts were noted from the 75% data. Adaptive cardiac multicycle (or multi-segment) algorithms were used to combine data from multiple cardiac cycles (up to 4) to optimize temporal resolution [13].…”

Evaluation of Coronary Venous Anatomy by Multislice Computed Tomography

“…Prior to placement of the pacemaker lead, patients would undergo an invasive cardiac venogram to see if they have suitable veins for CRT. Up to 10% -20% patients will not have suitable veins for CRT and will need to go for surgical placement of left ventricular pacemaker lead [12][13][14].…”