Acute intracranial hemorrhage in CT: benefits of sinogram-affirmed iterative reconstruction techniques

• Published in: American journal of neuroradiology : AJNR 2014-03, Vol.35 (3), p.445-449
• Main Authors: Bodelle, B, Klein, E, Naguib, N N N, Bauer, R W, Kerl, J M, Al-Butmeh, F, Wichmann, J L, Ackermann, H, Lehnert, T, Vogl, T J, Schulz, B
• Format: Article
• Language: English
• Subjects: Acute Disease; Adolescent; Adult; Aged; Aged, 80 and over; Evidence-Based Medicine Level 1; Humans; Image Interpretation, Computer-Assisted - methods; Image Processing, Computer-Assisted - methods; Intracranial Hemorrhages - diagnostic imaging; Middle Aged; Patient Safety; Tomography, X-Ray Computed; Young Adult
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.a3801

Acute intracranial hemorrhage represents a severe and time critical pathology that requires precise and quick diagnosis, mainly by performing a CT scan. The purpose of this study was to compare image quality and intracranial hemorrhage conspicuity in brain CT with sinogram-affirmed iterative reconstruction and filtered back-projection reconstruction techniques at standard (340 mAs) and low-dose tube current levels (260 mAs). A total of 94 consecutive patients with intracranial hemorrhage received CT scans either with standard or low-dose protocol by random assignment. Group 1 (n=54; mean age, 64 ± 20 years) received CT at 340 mAs, and group 2 (n=40; mean age, 57 ± 23 years) received CT at 260 mAs. Images of both groups were reconstructed with filtered back-projection reconstruction and 5 iterative strengths (S1-S5) and ranked blind by 2 radiologists for image quality and intracranial hemorrhage on a 5-point scale. Image noise, SNR, dose-length product (mGycm), and mean effective dose (mSv) were calculated. In both groups, image quality and intracranial hemorrhage conspicuity were rated subjectively with an excellent/good image quality. A higher strength of sinogram-affirmed iterative reconstruction showed an increase in image quality with a difference to filtered back-projection reconstruction (P < .05). Subjective rating showed the best score of image quality and intracranial hemorrhage conspicuity achieved through S3/S4-5. Objective analysis of image quality showed in an increase of SNR with a higher strength of sinogram-affirmed iterative reconstruction. Patients in group 2 (mean: 744 mGycm/1.71 mSv) were exposed to a significantly lower dose than those in group 1 (mean: 1045 mGycm/2.40 mSv, P < .01). S3 provides better image quality and visualization of intracranial hemorrhage in brain CT at 260 mAs. Dose reduction by almost one-third is possible without significant loss in diagnostic quality.