Noise reduction and image quality improvement of low dose and ultra low dose brain perfusion CT by HYPR-LR processing

• Published in: PloS one 2011-02, Vol.6 (2), p.e17098-e17098
• Main Authors: Krissak, Radko, Mistretta, Charles A, Henzler, Thomas, Chatzikonstantinou, Anastasios, Scharf, Johann, Schoenberg, Stefan O, Fink, Christian
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Algorithms; Attenuation; Biology; Brain; Brain - blood supply; Brain - diagnostic imaging; CAT scans; Computed tomography; Computer Science; Correlation; Correlation coefficient; Correlation coefficients; Datasets; Diagnostic systems; Drug dosages; Engineering; Evaluation; Feasibility studies; Female; Hair loss; Humans; Image quality; Image reconstruction; Male; Mathematics; Medical imaging; Medical imaging equipment; Medicine; Middle Aged; Noise; Noise control; Noise reduction; Nuclear medicine; Parenchyma; Patients; Perfusion; Perfusion Imaging - methods; Physics; Post-production processing; Quality; Quality assessment; Quality control; Quality improvement; Quality management; Radiation; Radiation (Physics); Radiation Dosage; Radiographic Image Enhancement - methods; Scanners; Sensors; Signal processing; Signal to noise ratio; Stroke; Time Factors; Tomography; Tomography, X-Ray Computed - methods; Tubes
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0017098

To evaluate image quality and signal characteristics of brain perfusion CT (BPCT) obtained by low-dose (LD) and ultra-low-dose (ULD) protocols with and without post-processing by highly constrained back-projection (HYPR)-local reconstruction (LR) technique. Simultaneous BPCTs were acquired in 8 patients on a dual-source-CT by applying LD (80 kV, 200 mAs, 14×1.2 mm) on tube A and ULD (80 kV, 30 mAs, 14×1.2 mm) on tube B. Image data from both tubes was reconstructed with identical parameters and post-processed using the HYPR-LR. Correlation coefficients between mean and maximum (MAX) attenuation values within corresponding ROIs, area under attenuation curve (AUC), and signal to noise ratio (SNR) of brain parenchyma were assessed. Subjective image quality was assessed on a 5-point scale by two blinded observers (1: excellent, 5: non-diagnostic). Radiation dose of ULD was more than six times lower compared to LD. SNR was improved by HYPR: ULD vs. ULD+HYPR: 1.9±0.3 vs. 8.4±1.7, LD vs. LD+HYPR: 5.0±0.7 vs. 13.4±2.4 (both p