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Erschienen in:
01.06.2015 | Computed Tomography
Image quality of low mA CT pulmonary angiography reconstructed with model based iterative reconstruction versus standard CT pulmonary angiography reconstructed with filtered back projection: an equivalency trial
Erschienen in: European Radiology | Ausgabe 6/2015
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Objective
To determine whether CT pulmonary angiography (CTPA) using low mA setting reconstructed with model-based iterative reconstruction (MBIR) is equivalent to routine CTPA reconstructed with filtered back projection (FBP).
Methods
This prospective study was approved by the institutional review board and patients provided written informed consent. Eighty-two patients were examined with a low mA MBIR-CTPA (100 kV, 20 mA) and 82 patients with a standard FBP-CTPA (100 kV, 250 mA). Region of interests were drawn in nine pulmonary vessels; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate the image quality of FBP-CTPA and low mA MBIR-CTPA.
Results
Compared to routine FBP-CTPA, low mA MBIR-CTPA showed no differences in the attenuation measured in nine pulmonary vessels, higher SNR (56 ± 19 vs 43 ± 20, p < 0.0001) and higher CNR (50 ± 17 vs 38 ± 18, p < 0.0001) despite a dose reduction of 93 % (p < 0.0001). The subjective image quality of low mA MBIR-CTPA was quoted as diagnostic in 98 % of the cases for patient with body mass index less than 30 kg/m2.
Conclusion
Low mA MBIR-CTPA is equivalent to routine FBP-CTPA and allows a significant dose reduction while improving SNR and CNR in the pulmonary vessels, as compared with routine FBP-CTPA.
Key Points
• Low mA MBIR-CTPA is equivalent to routine FBP-CTPA.
• MBIR-CTPA may be achieved with drastic (93 %) dose reduction.
• Low mA MBIR-CTPA should be studied in the setting of suspected PE.