Search

Rationale and Objectives Severe calcifications of the coronary arteries are still a major challenge in coronary computed tomography (CT) angiography (CCTA). Subtraction CCTA using a 320-detector row CT scanner has recently been introduced for patients with severe calcifications. However, the conventional subtraction CCTA method requires a long breath-holding time of approximately 20–40 seconds. This is a major problem in clinical practice because many patients may not be able to perform such a long breath-hold. We explored a modified subtraction CCTA method with a short breath-holding time to overcome this problem. Materials and Methods This study was approved by our institutional review board, and all patients gave written informed consent. A total of 12 patients with a coronary calcium score of >400 were enrolled in this study. All patients were unable to hold their breath for more than 20 seconds. Modified subtraction CCTA was performed using the bolus-tracking method. The acquisition protocol was adjusted so that the mask scan was acquired 10 seconds after the postcontrast scan during a single breath-hold. The subtraction image was obtained by subtracting the mask image data from the postcontrast image data. The breath-holding times were recorded. Enhancement of the coronary arteries in the subtraction images was assessed. Subjective image quality was evaluated in a total of 32 segments using a 4-point scale. Results The mean breath-holding time was 12.8 ± 0.8 seconds (range, 12–14 seconds). The average CT number in the coronary arteries was 288.6 ± 80.5 Hounsfield units (HU) in the subtraction images. Average image quality was significantly increased from 2.1 ± 0.9 with conventional CCTA to 3.1 ± 0.7 with subtraction CCTA ( P P = 0.001). Conclusions This preliminary study has shown that our modified subtraction CCTA method allows the breath-holding time to be shortened to

A 77-year-old woman presented with a 3-week history of low grade fever, appetite loss and dizziness. An electrocardiogram showed complete heart block. Echocardiography demonstrated severe aortic valve stenosis and a mass of probable vegetation 2 cm in diameter on the atrioventricular septum in the right atrium (RA), but no obvious intra-cardiac fistula. There was no growth of organism in blood cul tures. In the 4th week after admission, a harsh and continuous cardiac murmur was detected for the 1st time. Portable echocardiography revealed disappearance of the mass in the RA, and showed an intra-cardiac shunt from the left ventricle( LV) to RA. The shunt was closed by autologous pericardial patch form LV side and directly with mattress suture form RA side during the emergency operation. The aortic valve was replaced with bio-prosthetic valve (SJM Trifecta 19 mm). No organism was detected in the excised tissue, but antibiotics were continued for 2 months until a permanent pacemaker was inserted.

To explore the feasibility and diagnostic accuracy of modified subtraction coronary CT angiography (CCTA) with short breath-holding time in patients who have limited breath-hold capability and severe coronary artery calcification.11 patients with a coronary calcium score400 underwent CCTA using a modified subtraction protocol. All patients were unable to hold their breath for more than 20 s. Subjective image quality using a four-point scale and the presence of significant (50%) luminal stenosis were assessed for each calcified or stented segment on both conventional CCTA and modified subtraction CCTA images and compared with invasive coronary angiography (ICA) as the gold standard.The mean breath-holding time was 13.0 ± 0.9 s. A total of 35 calcified or stented coronary segments were evaluated. The average image quality was increased from 2.1 ± 0.9 with conventional CCTA to 3.1 ± 0.7 with subtraction CCTA (p 0.001). The segment-based diagnostic accuracy for detecting significant stenosis according to ICA revealed an area under the receiver-operating characteristic curve of 0.722 for conventional CCTA and 0.892 for subtraction CCTA (p = 0.036).Modified subtraction CCTA allows the breath-holding time to be shortened to15 s. As compared with conventional CCTA, modified subtraction CCTA showed improvement in image quality and diagnostic accuracy in patients with limited breath-hold capability and severe calcification.Modified subtraction CCTA can improve the diagnostic accuracy in patients with a high calcium score and patients who are unable to perform long breath-holds.

Severe calcifications of the coronary arteries are still a major challenge in coronary computed tomography (CT) angiography (CCTA). Subtraction CCTA using a 320-detector row CT scanner has recently been introduced for patients with severe calcifications. However, the conventional subtraction CCTA method requires a long breath-holding time of approximately 20-40 seconds. This is a major problem in clinical practice because many patients may not be able to perform such a long breath-hold. We explored a modified subtraction CCTA method with a short breath-holding time to overcome this problem.This study was approved by our institutional review board, and all patients gave written informed consent. A total of 12 patients with a coronary calcium score of400 were enrolled in this study. All patients were unable to hold their breath for more than 20 seconds. Modified subtraction CCTA was performed using the bolus-tracking method. The acquisition protocol was adjusted so that the mask scan was acquired 10 seconds after the postcontrast scan during a single breath-hold. The subtraction image was obtained by subtracting the mask image data from the postcontrast image data. The breath-holding times were recorded. Enhancement of the coronary arteries in the subtraction images was assessed. Subjective image quality was evaluated in a total of 32 segments using a 4-point scale.The mean breath-holding time was 12.8 ± 0.8 seconds (range, 12-14 seconds). The average CT number in the coronary arteries was 288.6 ± 80.5 Hounsfield units (HU) in the subtraction images. Average image quality was significantly increased from 2.1 ± 0.9 with conventional CCTA to 3.1 ± 0.7 with subtraction CCTA (P 0.001). With subtraction CCTA, the number of non-diagnostic segments was significantly reduced from 53% to 19% (P = 0.001).This preliminary study has shown that our modified subtraction CCTA method allows the breath-holding time to be shortened to15 seconds. This may substantially improve the success rate of subtraction CCTA by reducing artifacts and allowing this technique to be applied to patients who are unable to perform a long breath-hold.