Alexander Ewald Lembcke MD, Presenter: Nothing to Disclose

Reny Luhur MD, Abstract Co-Author: Nothing to Disclose

Patrick Alexander Hein MD, Abstract Co-Author: Nothing to Disclose

Tahir Durmus MD, Abstract Co-Author: Nothing to Disclose

Kay-Geert A. Hermann MD, Abstract Co-Author: Nothing to Disclose

Bernd K. Hamm MD, Abstract Co-Author: Research Consultant, Bayer AG Research Consultant, Toshiba Corporation Stockholder, Siemens AG Stockholder, General Electric Company Research grant, Toshiba Corporation Research grant, Koninklijke Philips Electronics NV Research grant, Siemens AG Research grant, General Electric Company Research grant, Elbit Medical Imaging Ltd Research grant, Bayer AG Research grant, Guerbet AG Research grant, Bracco Group Research grant, B. Braun Melsungen AG Research grant, KRAUTH medical KG Research grant, Boston Scientific Corporation Equipment support, Elbit Medical Imaging Ltd Investigator, Copenhagen Malmo Contrast AB

To evaluate the feasibility and accuracy of 320-row detector computed tomography (CT) for measuring left ventricular (LV) dimensions and function at a radiation exposure of about 1 mSv.

A total of 23 patients (14 men, age 60.3±13.7 years, body weight 81.1±15.1 kg) underwent a contrast enhanced 320-row detector CT (AquilionOne, Toshiba, Japan). A dynamic volume data set of the entire heart was acquired during a single beat using following parameters: 100 kV tube voltage, 100 mA tube current, 350 ms rotation time and 200x0.5 or 240x0.5 mm collimation (z-axis coverage of 10 and 12 cm, respectively). A data set with 20 phases (in 5 % steps throughout the RR-interval) was created and analyzed on an offline workstation. Multiplanar reformations along the long and short heart axis were generated with 8 mm thickness. Using the implemented software end-diastolic, end-systolic and stroke volumes (EDV, ESV, SV), ejection fraction (EF) and myocardial mass (MM) were determined. Effective radiation dose was estimated using the dose-length-product displayed on the scanner. Magnetic resonance imaging was performed within 2 days and served as standard of truth.

Calculated radiation dose was 0.92±0.27 mSv (range 0.56-1.32 mSv). All data sets had sufficient image quality allowing a clear delineation of the myocardial borders. Comparison between CT and MRI revealed no significant differences for EDV, ESV, SV and EF (127.0±52.3 vs. 133.5±41.4 ml, 58.6±49.2 vs. 59.9±41.3 ml, 68.3±27.4 vs. 73.7±24.6 ml, 59.1±19.3 vs. 58.2±17.1 %, each with p>0.05) whereas a small bias was found for MM (135.3±33.2 vs. 127.6±32.5 g, p<0.05). Correlation coefficients for EDV, ESV, SV, EF and MM were r=0.84, r=0.93, r=0.81, r=0.94, and r=0.94, respectively (each with p<0.05). Limits of agreement for EDV, ESV, SV, EF and MM were +49.6/-62.8 ml,+37.3/-39.9 ml, +26.5/-37.1 ml,+13.2/-11.6 %, and +30.2/-14.8 g, respectively. For all parameters intra- and interobserver variability did not differ significantly between CT and MRI.

Dedicated CT scan techniques dramatically reduce the radiation exposure in functional cardiac imaging while maintaining a high measuring accuracy.

A low radiation exposure may facilitate the acceptance of CT as additional modality for assessing LV function, especially in patients with poor sonication conditions.

Lembcke, A, Luhur, R, Hein, P, Durmus, T, Hermann, K, Hamm, B, Quantification of Global Left Ventricular Function Using 320 Row Detector Computed Tomography: Low Radiation Exposure with Single Beat Cardiac Imaging and Adjusted X-ray Tube Settings.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11012164.html