Reduction of metal artifacts due to dental hardware in computed tomography angiography: assessment of the utility of model-based iterative reconstruction.

PURPOSE: The aim of this study is to assess the value of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) for reduction of metal artifacts due to dental hardware in carotid CT angiography (CTA). METHODS: Thirty-seven patients with dental hardware who underwent carotid CTA were included. CTA was performed with a GE Discovery CT750 HD scanner and reconstructed with filtered back projection (FBP), ASIR, and MBIR. We measured the standard deviation at the cervical segment of the internal carotid artery that was affected most by dental metal artifacts (SD1) and the standard deviation at the common carotid artery that was not affected by the artifact (SD2). We calculated the artifact index (AI) as follows: AI = [(SD1)2 - (SD2)2]1/2 and compared each AI for FBP, ASIR, and MBIR. Visual assessment of the internal carotid artery was also performed by two neuroradiologists using a five-point scale for each axial and reconstructed sagittal image. The inter-observer agreement was analyzed using weighted kappa analysis. RESULTS: MBIR significantly improved AI compared with FBP and ASIR (p < 0.001, each). We found no significant difference in AI between FBP and ASIR (p = 0.502). The visual score of MBIR was significantly better than those of FBP and ASIR (p < 0.001, each), whereas the scores of ASIR were the same as those of FBP. Kappa values indicated good inter-observer agreements in all reconstructed images (0.747-0.778). CONCLUSIONS: MBIR resulted in a significant reduction in artifact from dental hardware in carotid CTA.

[Comparison of the effects of prophylactic antibiotic therapy and cost-effectiveness between cefazolin (CEZ) and Sulbactam/Ampicillin (SBT/ABPC) in gastric cancer surgery employing clinical pathway].

The present study was designed to investigate the effects of prophylactic antibiotic therapy and the cost-effectiveness of Cefazolin (CEZ) and Sulbactam/Ampicillin (SBT/ABPC) in gastric cancer surgery employing clinical pathway. 157 patients (62 in the CEZ group and 95 in the SBT/ABPC group), who underwent surgery for gastric cancer at the First Department of Surgery of our hospital, were investigated. There was no significant difference between the groups with regard to sex, age, incidence of complication, stage of cancer, surgical method, operative time and blood loss, length of hospitalization, the appearance of systemic inflammatory response syndrome (SIRS), changes body temperature, white blood cell count (WBC), C-reactive protein (CRP), or clinical outcome of postoperative care by a nurse during post-operation for 7 days. The prophylactic effect of infection was also no different between the CEZ (69.4%) and SBT/ABPC (69.5%) groups. In contrast, decision analysis strongly indicated that the anticipate cost of antibiotics was higher in the latter group (yen 20402) than in the CEZ group (yen 15556), suggesting that the prophylactic effect of CEZ may be more cost-effective. Thus, evaluations of pharmacotherapy from the aspect of cost may be one of the important responsibility of hospital pharmacists in the future.