Objective
To compare coronary artery visibility in free-breathing young children with congenital heart disease on cardiac 64-slice CT between dual-source ECG-triggered sequential (DSET) scan and single-source non-ECG-synchronized spiral (SSNE) scan.

Materials and methods
In 93 young children, 108 cardiac 64-slice CT examinations were performed during free-breathing. Visibility of coronary arteries and side branches was compared between SSNE and DSET scans. Heart rates and trigger delays for DSET scan were recorded. Effective dose of each scan technique was calculated.

Results
Visual grades were significantly higher (P < 0.001 or = 0.011) on DSET scan than on SSNE scan except for the distal left anterior descending artery. Coronary arteries were traceable in 79.3 % on DSET scan and 54.3 % on SSNE scan in the overlapped scan range (P < 0.0001), and 97.1% and 71.9 % for the origins and proximal segments (P < 0.0001). Visibility of side branches was improved on DSET scan by a factor of 2.0. Heart rates and trigger delays for DSET scan were 131 +/- 24 beats per min and 199 +/- 44 ms, respectively. Effective doses of DSET and SSNE scans were 0.36 +/- 0.12 mSv and 0.99 +/- 0.23 mSv, respectively.

Conclusion
DSET scan improves visibility of coronary arteries on cardiac 64-slice CT in free-breathing young children with congenital heart disease, compared with SSNE scan.

Full text: Pediatr Radiol. 2010 May 13

Authors: Goo HW, Yang DH

Materials and Methods
DECT examinations acquired with a dual source CT of 71 regions from 41 patients were evaluated with respect to image quality, amount of urate deposits and their location. The amount of urate deposits was described using a 4-stage scale: none (1), minimal punctual (up to 2 mm) (2), at least moderate (bigger than 2 mm) (3), soft tissue or osseus tophi (4). The DECT results were compared with the findings of the diagnostic tools currently in use.

Results
The DECTs of peripheral regions showed excellent image quality, while the image quality was poor in the regions of the trunk. Patients (n) and regions (r) with a score of 3 (n = 23, r = 44), 4 (n = 5, r = 8 ) and 1 (n = 2, r = 2) showed a highly significant correlation (p < 0.01) with the currently available diagnostic tools. In patients or regions with a score of 2 (n = 7, r = 11), the urate deposits were asymptomatic, the serum urate levels were partly elevated (43 %) and partly normal (57 %). The symptoms were ultimately able to be associated with a differential diagnosis. The urate deposits were found in tendons (57), articular synovia (25), cartilage (17), soft tissue tophi (8), osseus tophi (5), cruciate ligaments (7), and menisci (7).

Conclusion
DECT allows specific and quantitative visualization of urate deposits in peripheral regions. Taking into account the amount of urate deposits shown in DECT, the diagnosis of gout can be stated reliably. Based on our experience and results, DECT greatly benefits the routine diagnosis of gout in peripheral regions.

Authors: A. Artmann, M. Ratzenböck, I. Noszian, K. Trieb

Full Text: Rofo. 2010 Mar;182(3):261-6. Epub 2009 Oct 27.

Conclusion: The ability of dual-energy CT to diagnose early gout and its use as a problem-solving tool is shown here. Diagnosis of subclinical gout could avert associated long-term complications, thereby reducing disease burden and improving overall quality of life.

Full text: AJR Am J Roentgenol. 2010 Apr;194(4):1072-8.

Authors: Savvakis Nicolaou, Charlotte Jane Yong-Hing, Sandro Galea-Soler, Daniel J. Hou, Luck Louis, Peter Munk

Materials and Methods
An anthropomorphic Alderson phantom was assembled with thermoluminescent detectors (TLD) and its chest was scanned on a Dual Source CT (Siemens Somatom Definition) in dual energy mode at 140 and 80 kVp with 14 x 1.2 mm collimation. The same was performed on another Dual Source CT (Siemens Somatom Definition Flash) at 140 kVp with 0.8 mm tin filter (Sn) and 100 kVp at 128 x 0.6 mm collimation. Reference scans were obtained at 120 kVp with 64 x 0.6 mm collimation at equivalent CT dose index of 5.4 mGy*cm. Syringes filled with water and 17.5 mg iodine/mL were scanned with the same settings. Dose was calculated from the TLD measurements and the dose length products of the scanner. Image noise was measured in the phantom scans and CNR and spectral contrast were determined in the iodine and water samples. E/DLP conversion factors were calculated as ratio between the measured dose form the TLDs and the dose length product given in the patient protocol.

Results
The effective dose measured with TLDs was 2.61, 2.69, and 2.70 mSv, respectively, for the 140/80 kVp, the 140 Sn/100 kVp, and the standard 120 kVp scans. Image noise measured in the average images of the phantom scans was 11.0, 10.7, and 9.9 HU (P > 0.05). The CNR of iodine with optimized image blending was 33.4 at 140/80 kVp, 30.7 at 140Sn/100 kVp and 14.6 at 120 kVp. E/DLP conversion factors were 0.0161 mSv/mGy*cm for the 140/80 kVp protocol, 0.0181 mSv/mGy*cm for the Sn140/100 kVp mode and 0.0180 mSv/mGy*cm for the 120 kVp examination.

Conclusion
Dual Energy CT is feasible without additional dose. There is no significant difference in image noise, while CNR can be doubled with optimized dual energy CT reconstructions. A restriction in collimation is required for dose-neutrality at 140/80 kVp, whereas this is not necessary at 140 Sn/100 kVp. Thus, CT can be performed routinely in Dual Energy mode without additional dose or compromises in image quality.

Full text: Invest Radiol. 2010 Jun;45(6):347-53

Authors: Schenzle JC, Sommer WH, Neumaier K, Michalski G, Lechel U, Nikolaou K, Becker CR, Reiser MF, Johnson TR.

Authors: Thomas C, Patschan O, Ketelsen D, Tsiflikas I, Reimann A, Brodoefel H, Buchgeister M, Nagele U, Stenzl A, Claussen C, Kopp A, Heuschmid M, Schlemmer HP.

Full text: Eur Radiol. 2009;19:1553-9.

Methods
Fifty-one consecutive patients pre- or post-cardiovascular surgery were examined with adaptive sequential tube current modulated (pECG(dual-step)) 128-slice dual-source CT without heart rate control (main padding window: 40 % RR interval > 65 bpm/70 % RR interval < 65 bpm). Image quality of coronary arteries was graded (4-point scale), and cardiac function was evaluated.

Results
Mean HR was 68 bpm. Thirty-seven patients were in stable sinus rhythm (SR); 14 had arrhythmia. Image quality of coronary arteries was diagnostic in 804/816 (98 %) of segments. The number of non-diagnostic segments was higher in patients with arrhythmia as compared to those in SR (4 % vs. 0.5 %; p = 0.01), and there were fewer segments with excellent image quality (79 % vs. 94 %; p < 0.001) and more segments with impaired image quality (p < 0.001 and p = 0.002). Global and regional LV function could be evaluated in 41 (80 %) and 47 (92 %) patients, and valvular function in 48 (94 %). In 11/14 of patients with arrhythmia, the second step switched to full mAs, increasing radiation exposure to 8.6 mAs (p < 0.001). The average radiation dose was 3.8 mSv (range, 1.7-7.9) in patients in SR.

Conclusion
pECG(dual-step)128-slice DSCT is feasible for the evaluation of coronary arteries and cardiac function without heart rate control in patients in stable sinus rhythm at a low radiation dose.

Authors: Feuchtner G, Götti R, Plass A, Baumueller S, Stolzmann P, Scheffel H, Wieser M, Marincek B, Alkadhi H, Leschka S.

Full text available: Eur Radiol. 2010 Apr 21. [Epub ahead of print]

We have the pleasure to welcome Fabian Bamberg M.D., M.P.H. in our Dual Source CT community. He is Fellow in Clinical Radiology at the Department of Clinical Radiology Ludwig-Maximilians-University of Munich, Germany.

His fields of expertise are: cardiovascular imaging, coronary CTA, myocardial perfusion imaging, cost-effectiveness analysis

Read more about Dr. Florian Bamberg or ask him questions about DSCT.