Single-source dual-energy computed tomography for the detection of bone marrow lesions: impact of iterative reconstruction and algorithms.

PURPOSE: To compare the diagnostic performance of different reconstruction algorithms of single-source dual-energy computed tomography (DECT) for the detection of bone marrow lesions (BML) in patients with vertebral compression fracture using MRI as the standard of reference. MATERIAL AND METHODS: Seventeen patients with an age over 50 who underwent single-source DECT of the spine were included. The raw data (RD) were reconstructed using filtered back-projection (FBP) and iterative reconstruction (IR) with three iteration levels (IR1-IR3). Bone marrow images were generated using a three-material decomposition (3MD) and a two-material decomposition (2MD) algorithm and an RD-based approach. Three blinded readers scored the images for image quality and the presence of bone marrow lesions (BML). Only vertebrae with height loss were included. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The different reconstructions were compared using Dunn's multiple comparison test. RESULTS: Thirty-nine vertebrae were included. IR(1-3) showed superior sensitivity (87.5%) compared to FBP (75%) using 3MD but was comparable to RD (83.3%). All 2MD images were inferior (sensitivity < 38%). The image quality score was significantly higher for 3MD-IR(1-3) compared to 3MD-FBP (p < 0.0001) and all 2MD data sets (p < 0.03). This pattern was also supported by the SNR and CNR measurements. RD showed no significant improvement compared to IR. CONCLUSION: The image quality of bone marrow images acquired with DECT can be improved by using IR compared with FBP. RD-based reconstruction does not offer significant improvement over image data-based reconstruction. 2MD algorithms are not suitable for BML detection.

Expression of BCL-2 in liver grafts after adenoviral transfer improves survival following prolonged ischemia and reperfusion in rat liver transplantation.

UNLABELLED: Apoptosis represents a crucial mechanism of ischemia-reperfusion injury after liver transplantation. Bcl-2 may inhibit apoptosis. This study investigates the effect on ischemia/reperfusion injury and survival after rat liver transplantation of adenoviral bcl-2 transfer into donor livers. METHODS: A nonreplicative adenovirus, expressing bcl-2 under control of a tetracyclin-inducible promoter (adv TetOn bcl-2) was used to treat male Lewis rats in combination with a second adenovirus transferring the TetOn repressor protein under control of a cytomegalovirus promoter (advCMVRep). Virus induction was achieved by addition of doxycyclin to the drinking water. Controls were pretreated with a control adenovirus (advCMV GFP) or with doxycycline. Liver transplantations were performed after 16-hour graft storage. Bcl-2 expression was evaluated by Western blot and immunohistology. Survival was monitored for 7 days, and tissue specimens were collected at 24 hours and 7 days post reperfusion. RESULTS: After pretreatment with advTetOn bcl-2/adv CMVRep, intrahepatic bcl-2 expression was evident at 24 hours and 7 days but was absent among controls. Bcl-2 expression was detected in hepatocytes and, to a high degree, in sinusoidal lining cells. TUNEL-positive sinusoidal lining cells were strikingly reduced after bcl-2 transfer (0.1 +/- 0.3 cells/hpf, mean +/- SD) compared to control virus (4.8 +/- 2.3) or doxycyclin-treated grafts (1.3 +/- 0.2); P < .05. After bcl-2 treatment, survival after transplantation was 100%, whereas it was 50% in both control groups (P = .035). CONCLUSION: The study shows the feasibility of transient, doxycyclin-controlled adenoviral gene transfer in a transplantation model. Bcl-2 expression increased survival after ischemia/reperfusion in rat liver transplantation, potentially through protection of sinusoidal lining cells.