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Endoleak and in-stent thrombus detection with CT angiography in a thoracic aortic aneurysm phantom at different tube energies using filtered back projection and iterative algorithms
- Source :
- Radiology, vol. 271, no. 2, pp. 574-584
- Publication Year :
- 2014
-
Abstract
- PURPOSE: To determine the lower limit of dose reduction with hybrid and fully iterative reconstruction algorithms in detection of endoleaks and in-stent thrombus of thoracic aorta with computed tomographic (CT) angiography by applying protocols with different tube energies and automated tube current modulation. MATERIALS AND METHODS: The calcification insert of an anthropomorphic cardiac phantom was replaced with an aortic aneurysm model containing a stent, simulated endoleaks, and an intraluminal thrombus. CT was performed at tube energies of 120, 100, and 80 kVp with incrementally increasing noise indexes (NIs) of 16, 25, 34, 43, 52, 61, and 70 and a 2.5-mm section thickness. NI directly controls radiation exposure; a higher NI allows for greater image noise and decreases radiation. Images were reconstructed with filtered back projection (FBP) and hybrid and fully iterative algorithms. Five radiologists independently analyzed lesion conspicuity to assess sensitivity and specificity. Mean attenuation (in Hounsfield units) and standard deviation were measured in the aorta to calculate signal-to-noise ratio (SNR). Attenuation and SNR of different protocols and algorithms were analyzed with analysis of variance or Welch test depending on data distribution. RESULTS: Both sensitivity and specificity were 100% for simulated lesions on images with 2.5-mm section thickness and an NI of 25 (3.45 mGy), 34 (1.83 mGy), or 43 (1.16 mGy) at 120 kVp; an NI of 34 (1.98 mGy), 43 (1.23 mGy), or 61 (0.61 mGy) at 100 kVp; and an NI of 43 (1.46 mGy) or 70 (0.54 mGy) at 80 kVp. SNR values showed similar results. With the fully iterative algorithm, mean attenuation of the aorta decreased significantly in reduced-dose protocols in comparison with control protocols at 100 kVp (311 HU at 16 NI vs 290 HU at 70 NI, P ≤ .0011) and 80 kVp (400 HU at 16 NI vs 369 HU at 70 NI, P ≤ .0007). CONCLUSION: Endoleaks and in-stent thrombus of thoracic aorta were detectable to 1.46 mGy (80 kVp) with FBP, 1.23 mGy (100 kVp) with the hybrid algorithm, and 0.54 mGy (80 kVp) with the fully iterative algorithm.
- Subjects :
- medicine.medical_specialty
Endoleak
medicine.medical_treatment
Contrast Media
Iterative reconstruction
Radiation Dosage
Thoracic aortic aneurysm
Imaging phantom
Aortic aneurysm
Postoperative Complications
medicine
Humans
Radiology, Nuclear Medicine and imaging
Thrombus
Aortic Aneurysm, Thoracic
medicine.diagnostic_test
Phantoms, Imaging
business.industry
Angiography
Stent
Thrombosis
medicine.disease
Algorithms
Angiography/methods
Aortic Aneurysm, Thoracic/radiography
Aortic Aneurysm, Thoracic/surgery
Contrast Media/diagnostic use
Endoleak/etiology
Endoleak/radiography
Postoperative Complications/etiology
Postoperative Complications/radiography
Radiographic Image Interpretation, Computer-Assisted
Stents
Thrombosis/etiology
Thrombosis/radiography
Tomography, X-Ray Computed/methods
Imaging
Radiology
Tomography
Tomography, X-Ray Computed
business
Algorithm
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Radiology, vol. 271, no. 2, pp. 574-584
- Accession number :
- edsair.doi.dedup.....1ae91435cbf455716c265d92726f06fc