Abstract
To compare the image characteristics, effective dose and estimated organ dose to the female breast in pulmonary MDCT angiography (MDCTA), reconstructed with either standard filtered back projection (FBP), or iterative reconstruction in image space (IRIS). Pulmonary MDCTA performed in 116 females (age 18 - 77 years; body mass index 15 - 48) was reconstructed with FBP (n=52) or IRIS (n=64). Scans were acquired on a 128-row MDCT system using automatic tube current modulation, 100 kV tube voltage, and a quality reference mAs value of 120 (FBP) and 80 (IRIS). Dose was calculated from CT dose index (CTDIvol) and dose length product (DLP) values utilising ImPACT software. Image noise was measured within the pulmonary artery. Qualitative visual assessment of the scans was performed (1=negligible noise, 5=noise obscuring diagnostic information). The average CTDIvol yielded 4.33 mGy for FBP and 3.54 mGy for IRIS, respectively (18.2% decrease). The average effective scan dose was 2.73±0.57 mSv (FBP) and 2.29±0.68 mSv (IRIS), respectively (16.1% decrease). The estimated average organ dose to the breast decreased from 5.1±1.1 mGy (FBP) to 4.2±1.2 mGy (IRIS, 17.6% decrease). No non-diagnostic scans (score 5) were encountered in either group. Significant improvement in image noise levels (P<0.01) and subjective image quality (P<0.02) were noted in IRIS group. Pulmonary MDCTA utilizing a 100 kV technique, automatic tube current modulation, and iterative image reconstruction offers robust results in routine conditions among an unselected female population, with breast doses being comparable to two-view digital mammography. Moreover, iterative reconstruction offers improvements in both image noise and visual perception of the scans, thus suggesting a potential for further dose reduction.
Highlights
Radiation dose resulting from medical exposure is continuously rising in the population
The purpose of this study is to compare the image characteristics and effective and estimated organ dose to the female breast in pulmonary multidetector CT angiography (MDCTA) using both the standard filtered back projection (FBP) technique and iterative reconstruction in image space (IRIS)
The groups of FBP and IRIS scans showed no statistically significant differences when evaluating the mean attenuation values measured within the pulmonary artery (FBP: 358 HU; IRIS: 371 HU; P=0.66); craniocaudal coverage of scans (FBP: 262 mm; IRIS: 271 mm; P=0.09); or body mass index of the subjects
Summary
Radiation dose resulting from medical exposure is continuously rising in the population. Computed tomography is the major contributor, accounting for more than two thirds of the entire cumulative medical exposure[2]. To reverse this unfavourable trend, attributed mainly to the continuously increasing number of CT procedures, the adoption of adequate precautions is of utmost importance. Among the more promising approaches to dose reduction is the technique of iterative reconstruction of CT images which reduces radiation exposure by significantly supressing image noise[3,4]. The purpose of this study is to compare the image characteristics and effective and estimated organ dose to the female breast in pulmonary multidetector CT angiography (MDCTA) using both the standard filtered back projection (FBP) technique and iterative reconstruction in image space (IRIS). A brief review of the literature covering the topics of effective and breast dose in pulmonary MDCTA as well as dose saving strategies is performed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
