A Novel Bioreactor System Capable of Simulating the In Vivo Conditions of Synovial Joints.

Any significant in vitro evaluation of cartilage tissue engineering and cartilage repair strategies has to be performed under the harsh conditions encountered in vivo within synovial joints. To this end, we have developed a novel automated physiological robot reactor system (PRRS) that is capable of recapitulating complex physiological motions and load patterns within an environment similar to that found in the human knee. The PRRS consists of a mechanical stimulation unit (MSU) and an automatic sample changer (ASC) within an environment control box in which the humidity, temperature, and gas composition are tightly regulated. The MSU has three linear (orthogonal) axes and one rotational degree of freedom (around the z-axis). The ASC provides space for up to 24 samples, which can be allocated to individual stimulation patterns. Cell-seeded scaffolds and ex vivo tissue culture systems were established to demonstrate the applicability of the PRRS to the investigation of the effect of load and environmental conditions on engineering and maintenance of articular cartilage in vitro. The bioreactor is a flexible system that has the potential to be applied for culturing connective tissues other than cartilage, such as bone and intervertebral disc tissue, even though the mechanical and environmental parameters are very different.

Visualization of hypervascular liver lesions During TACE: comparison of angiographic C-arm CT and MDCT.

OBJECTIVE: The purpose of our study was to evaluate the diagnostic accuracy and scan coverage of flat-detector C-arm CT compared with that of biphasic MDCT for depicting malignant hepatic lesions in patients with hypervascular liver tumors before they undergo transarterial chemoembolization (TACE). MATERIALS AND METHODS: Fifteen patients with either hepatocellular carcinoma (HCC, n = 8) or hypervascular liver metastases from uveal melanoma (n = 7) underwent arterial and portal venous C-arm CT of the liver using intraarterial contrast media administration directly before TACE. The number and location of their hepatic malignancies were compared with those on MDCT. The scan coverage was documented and the liver diameter measured on MDCT. RESULTS: Compared with MDCT, the sensitivity and specificity for segmental tumor involvement were 97% (76/78) and 85% (28/33), respectively, for reader 1, and 99% (77/78) and 79% (24/29), respectively, for reader 2. Complete scan coverage of the liver was obtained in five of the 15 patients with C-arm CT. In patients with incomplete scan coverage on C-arm CT, the craniocaudal liver diameter was significantly larger than in those patients with complete scan coverage (mean [95% CI], 22.7 [19.5-25.9] cm vs 20.2 [15.4-25.0] cm, p = 0.0193). CONCLUSION: Biphasic arterial and portal venous C-arm CT showed a high sensitivity for the detection of malignant liver lesions. However, the liver could not be visualized completely in two thirds of the patients. Therefore, the current scan range limitations need to be overcome to make C-arm CT a valuable adjunct to MDCT for preprocedure evaluation and postprocedure follow-up imaging.

Three-dimensional reconstruction allows accurate quantification and length measurements of coronary artery stenoses.

AIMS: The aim of this prospective study was to evaluate the feasibility and accuracy of a recently developed 3D system (CardiOp-B; Paieon Medical Ltd., Israel) as compared to a validated quantitative coronary angiography (QCA) system (Siemens Quantcor, Siemens Medical Solutions). METHODS AND RESULTS: In patients scheduled for heart catheterisation, minimal lumen diameter (MLD) and diameter-derived percent stenosis (DPS) were obtained for CAS (>50%) using both QCA and the 3D-system. To estimate stenosis length, a non-inflated balloon was inserted into the stenosis and the distance between balloon markers was measured using both methods and then compared to the known distance between the markers. In 61 patients 79 lesions were analysed. MLD measurements showed a good agreement between QCA and 3D with a mean difference of 0.08+/-0.035 mm. Reference diameter was 2.61+/-0.67 for 3D and 2.42+/-0.61 mm for QCA and 54.79+/-9.20% vs. 58.75+/-8.15% for the %-stenosis range, respectively. The mean true balloon length was 12.8 mm+/-3.8 mm. Lengths determined by the 3D system were 13.0+/-4.0 mm and 11.3+/-3.8 mm by QCA, respectively. CONCLUSIONS: Evaluation of CAS using the novel 3D system was feasible and showed equivalent results to validated QCA measurements. Length measurements seemed to be more accurate by the 3D system as compared to QCA. Therefore, this 3D-system can be used to guide decisions in interventional cardiology.